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  • Ultrastructure  (51)
  • phosphorus  (38)
  • hypertension  (31)
  • Springer  (120)
  • Cambridge University Press
  • Frontiers Media
  • 2020-2022
  • 1980-1984  (120)
  • 1975-1979
  • 1982  (120)
Collection
Keywords
Publisher
  • Springer  (120)
  • Cambridge University Press
  • Frontiers Media
Years
  • 2020-2022
  • 1980-1984  (120)
  • 1975-1979
Year
  • 1
    Electronic Resource
    Electronic Resource
    Effects of nitrogen and phosphorus fertilizers on unshaded Amazon cocoa in Nigeria (1982)
    Springer
    Nutrient cycling in agroecosystems 3 (1982), S. 13-16 
    Details
    ISSN: 1573-0867
    Keywords: cocoa ; nitrogen ; phosphorus ; soil analysis ; Nigeria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract No extensive investigation on the effect of fertilizers on Amazon cocoa variety (Theobroma cacao L.) has been performed in Nigeria. Therefore eight fertilizer treatments involving nitrogen and phosphorus, replicated six times at four locations across southern Nigeria, were established in 1973. The four N levels (N0, N1, N2, N3) involved were 0, 80, 160 and 240 kg ha−1 y−1, and the two P levels (P0, P1) were 0 and 67 kg ha−1 y−1. Results of the first 5 years of fertilizer application are reported. Response to P was observed at all locations, and the response was statistically significant at 2 of the locations. There was no response to the application of nitrogen. The data suggest, however, that there is only a response to phosphorus when nitrogen is applied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01063405
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural localization and gradient of activity of alkaline phosphatase activity during rodent odontogenesis (1982)
    Springer
    Calcified tissue international 34 (1982), S. 273-279 
    Details
    ISSN: 1432-0827
    Keywords: Odontogenesis ; Ultrastructure ; Alkaline phosphatase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The ultrastructural localization and gradient of activity of alkaline phosphatase were studied with respect to cell differentiation, matrix synthesis, and matrix mineralization in the incisor and molar teeth of 4-day-old Sprague-Dawley rats. The animals were perfused intracardially at room temperature with 2.5% glutaraldehyde in 0.1M sodium cacodylate (pH 7.4) with 3–4% sucrose. The jaws were dissected, immersion-fixed for 24 h, and the incisor and molar tooth germs removed. These were demineralized in 10% EDTA in NaOH (pH 7.4) with 7% sucrose. After reactivation of the enzyme with 0.1M MgCl in Tris-maleate buffer (pH 7.4) at 4°C, the teeth were incubated for alkaline phosphatase in a medium consisting of 6 ml 3% sodiumβ-glycerophosphate, 4 ml 0.2M Tris-HCl buffer (pH 9.2), 3 ml 1.6% MgSO4, 12 ml 0.5% lead citrate (pH⋍12), and 2.1 g sucrose. The pH was adjusted to 9.2 with 0.2M HCl, the volume made up to 30 ml, and the solution centrifuged for 10 min at 5000 rpm. Control teeth were incubated in medium minus the substrate. Finally, the specimens were routinely post-fixed and embedded for sectioning and examination with a Philips 300 electron microscope. A gradient of alkaline phosphatase activity was mapped along the developing teeth in the cells of the stratum intermedium, the proximal borders of the ameloblasts, the early dentine matrix, the predentine-dentine border, matrix vesicles, and the plasma membranes of odontoblasts and subodontoblast cells. The gradient of alkaline phosphatase activity was evident in the forming tooth from the cervical loop to the crown apex and was related to the cellular events, matrix synthesis, and matrix mineralization occurring during odontogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411250
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  • 3
    Electronic Resource
    Electronic Resource
    Electron microscopy of avian osteopetrosis induced by retrovirus MAV.2-O (1982)
    Springer
    Calcified tissue international 34 (1982), S. 382-390 
    Details
    ISSN: 1432-0827
    Keywords: Avian osteopetrosis ; Avian oncornavirus ; Ultrastructure ; Calcification ; Bone cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Diaphyseal tibial bone of 12.5 – 13-day and 19-day-old embryos and 20-day-old hatched chicks infected with retrovirus MAV.2-O were examined by transmission electron microscopy. The viruses were associated with lining osteoblasts and osteocytes. Whereas the infection of the osteoblast layer seemed to be a transient stage, virus association with osteocytes was a constant and main ultrastructural feature. The viruses were found either in the osteoid or in the periosteocytic space of the bone lacunae. They arose from dense cytoplasmic areas located near the cell plasmalemma via a budding process. The newly budded virus particles often had a large tail or a fine stalk-like process lost in the extracellular space. The viruses underwent calcification by deposition of inorganic material and were incorporated in the bone trabeculae. No production of virus was observed in typical osteoclasts with well-differentiated ruffled borders. The viral-induced avian osteopetrosis seemed to result from increased bone deposition through stimulation of osteoblast and osteocyte activities, whereas osteoclastic bone resorption seemed to be undisturbed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411272
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of food on the pharmacokinetics and pharmacodynamics of tolmesoxide in essential hypertensives (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 287-291 
    Details
    ISSN: 1432-1041
    Keywords: tolmesoxide ; hypertension ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Tolmesoxide is a new, direct-acting vasodilator drug for use in the management of both hypertension and cardiac failure. In 6 essential hypertensives inadequately controlled by combined β-blocker and diuretic therapy (average supine blood pressure 178/103 mm Hg) the addition of tolmesoxide (300–900 mg daily) was associated with a significant improvement in blood pressure control (average supine blood pressure 161/89 mmHg). The effect of food on the pharmacokinetics and pharmacodynamics of tolmesoxide have also been studied because, particularly at higher doses, the drug has been associated with upper gastrointestinal upset and it has been empirically recommended that it be taken with food. The blood pressure and heart rate responses were not significantly different when tolmesoxide was taken fasting or with food. Food resulted in a significant reduction in the peak plasma tolmesoxide concentration (2.14 µg/ml compared to 2.97 µg/ml) and a significant increase in the time to reach peak plasma concentration (1.67 h compared to 0.63 h). Although there was no impairment of its hypotensive effect, food significantly altered the pharmacokinetics of tolmesoxide and may therefore be useful in reducing the gastrointestinal disturbance associated with its use. In the treatment of inadequately controlled hypertension, tolmesoxide has a limited role as an alternative vasodilator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637615
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of labetalol and clonidine in hypertension (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 363-367 
    Details
    ISSN: 1432-1041
    Keywords: labetalol ; clonidine ; hypertension ; dose titration ; bendrofluazide ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of labetalol (L) was compared with that of clonidine (C) in a randomized cross-over study in 17 hypertensive outpatients on bendrofluazide (B). After treatment for two weeks with B (5 mg qd), either L (100 mg tid) or C (0.1 mg tid) was given and their doses were titrated at 2-weekly visits until normotension was achieved, or intolerable side-effects occurred. The treatment with B and L or C was then continued in a cross-over fashion for two 6-week periods, with 3 week diuretic washouts and subsequent dose-titration periods between the treatment periods. At the end of B, the supine blood pressure (BP) was 156/101, and at the end of B + L and B + C it was 136/91 (p〈0.001) and 137/91 (p〈0.001), respectively, pooling the data from both periods. At the end of B, the standing BP was 155/115, and at the end of B + L and B + C 134/100 (p〈0.001) and 139/106 (p〈0.001), respectively. The mean daily doses required were L 476mg and C 0.335 mg. On a weight basis, labetalol had about 1/1400 of the potency of clonidine. 12 patients complained of tiredness and dry mouth on clonidine and 2 patients of unsteadiness on labetalol. Labetalol caused a psoriasiform rash on the hands in one patient and limb weakness in one patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542319
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  • 6
    Electronic Resource
    Electronic Resource
    Prazosin depression of baroreflex function in hypertensive man (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 7-14 
    Details
    ISSN: 1432-1041
    Keywords: prazosin ; baroreflexes ; hypertension ; reflex tachycardia ; alpha adrenergic blockade ; dopamine-beta-hydroxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Prazosin is a post synaptic alpha adrenergic blocker effective in hypertension, whose hypotensive effect is unaccompanied by reflex tachycardia or hyperreninemia, nor by other evidence of increased sympathetic activity. We studied the baroreceptor reflex arc as a potential mediator of these effects. Twenty-two essential hypertensive men were treated with prazosin alone versus placebo, and experienced a blood pressure fall (from 114.8±3.6 down to 101.1±2.5 mm Hg,p〈0.005) unaccompanied by any change in heart rate, plasma renin activity, or several other indices of sympathetic nervous system activity (plasma dopamine-β-hydroxylase activity; urinary excretion of free catecholamines and vanillyl mandelic acid; allp〉0.1). Concomitant with the blood pressure fall, there was a significant depression of baroreflex arc sensitivity, from 11.4±2.0 ms/mmHg down to 6.6±1.9 ms/mmHg (p〈0.05), without an associated change in cardiac vagal inhibition (291.2±46.2 versus 300.3±19.2 ms,p〉0.1). Baroreflex arc sensitivity depression may in part explain the lack of reflex sympathetic outflow noted during prazosin treatment of hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00606418
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  • 7
    Electronic Resource
    Electronic Resource
    Interaction between oxprenolol and indomethacin on blood pressure in essential hypertensive patients (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 197-201 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; oxprenolol ; indomethacin ; drug interaction ; hypotensive effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A double-blind, cross-over study in 16 patients with essential hypertension was carried out, to evaluate any possible interference by indomethacin, a known prostaglandin-synthetase inhibitor, with the antihypertensive effect of oxprenolol, a non-selective beta-adrenoceptor blocking agent. Both indomethacin and oxprenolol, as well as the two drugs combined, inhibited plasma renin activity; no change was found in urinary sodium excretion or body weight. Oxprenolol alone caused a highly significant decrease in the systolic (−10.4 mmHg,p〈0.001), diastolic (−7.4 mmHg,p〈0.001) and mean (−7.7 mmHg,p〈0.01) blood pressures, whereas indomethacin did not influence blood pressure. When the two drugs were given in combination, blood pressure decreased (systolic: −5.9 mmHg; diastolic: −4.0 mmHg; mean: −4.6 mmHg), but the changes induced in blood pressure were reduced by about 50% when compared with those in the oxprenolol alone period. The data show that indomethacin seems to interfere with the antihypertensive effect of oxprenolol, by an action which may be due to the inhibition of prostaglandin synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00545214
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  • 8
    Electronic Resource
    Electronic Resource
    Antihypertensive, saluretic and hypokalaemic effects of cyclothiazide in comparison with hydrochlorthiazide with amiloride supplement (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 495-499 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; cyclothiazide ; hydrochlorthiazide ; thiazide diuretics ; potassium-sparing diuretics ; saluretic effect ; hypokalaemia ; hyperuricaemia ; amiloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive, saluretic and hypokalaemic effects of a small dose of cyclothiazide (2.5 mg daily) were compared with those of a conventional dose of an hydrochlorthiazide-amiloride hydrochloride combination (50+5 mg daily). Both preparations were given to 13 patients with mild (WHO I) hypertension in a cross-over manner for six weeks, with an intervening wash-out phase of three weeks. The antihypertensive efficacy of cyclothiazide was well comparable to that of the hydrochlorthiazide-amiloride combination, although cyclothiazide tended to inhibit renal sodium reabsorption less than the combination. Cyclothiazide tended to cause hypokalaemia, apparently due to increased potassium loss, but with the present dosage none of the 13 patients developed marked hypokalaemia (serum potassium less than 3.3 mmol/l). Both drugs led to a comparable increase in serum urate concentration. Neither of the preparations affected creatinine or free-water clearance. The results suggest that even in relatively small doses thiazides effectively decrease blood pressure, and combining thiazides with potassium-sparing diuretics is advantageous only in patients with marked hypokalaemia and its associated risks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609621
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  • 9
    Electronic Resource
    Electronic Resource
    Response of blood pressure and plasma norepinephrine to propranolol, metoprolol and clonidine during isometric and dynamic excercise in hypertensive patients (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 275-279 
    Details
    ISSN: 1432-1041
    Keywords: beta-blocker ; hypertension ; clonidine ; plasma catecholamines ; metoprolol ; propranolol ; blood pressure responses ; isometric work ; dynamic work
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of metropolol (beta1-selective), propranolol (nonselective) and clonidine (central alpha-stimulant) on plasma norepinephrine, blood pressure and heart rate were assessed at rest, during isometric work and dynamic exercise in 15 patients with moderate hypertension. Metroprolol resulted in a lower diastolic blood pressure during isometric and dynamic exercise than propranolol, which was paralleled by a lower plasma norepinephrine level during dynamic work; both beta-adrenergic blocking compounds resulted in a lower heart rate in all test situations than that obtained with clonidine; clonidine produced similar control of diastolic blood pressure to that obtained with the beta-adrenergic blocking agents, but did not clearly attenuate the systolic blood pressure response to dynamic exercise. Plasma norepinephrine concentrations tended to be lowest following clonidine, especially during dynamic work. The findings support the hypothesis that the central action of clonidine inhibits peripheral release of norepinephrine, but is insufficient to attenuate cardiac stimulation by physical exercise. The fact that propranolol caused higher plasma norepinephrine concentrations than metoprolol during exercise may explain the difference in the blood pressure responses during exercise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637613
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  • 10
    Electronic Resource
    Electronic Resource
    Simplified antihypertensive therapy with pindolol retard (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 445-449 
    Details
    ISSN: 1432-1041
    Keywords: pindolol ; hypertension ; retard formulation ; plasma levels ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary 36 out of 52 patients with essential hypertension, whose blood pressure was not normalized with pindolol 15 mg per day, were treated with 30 mg per day for four to six weeks. Pindolol was administered in random order, either as 15 mg twice daily or as one 30 mg retard tablet once daily. Blood pressure was lowered from mean pretreatment levels of 174/111 mmHg to 149/98 mmHg by 15 mg b.d., and to 145/97 mmHg by 30 mg retard. In five patients diurnal variations in blood pressure and plasma pindolol levels were determined. At all times during the day blood pressure was at least as well controlled by 30 mg retard as by 15 mg b.d. Plasma concentration maxima were similar with both forms, but a higher concentration was maintained for a longer time after the retard tablet. Pindolol 30 mg was well tolerated and the incidence of side effects was lower than during treatment with 15 mg b.d. Thus, patients requiring high doses of pindolol for control of hypertension can safely and conveniently be treated with a single tablet of 30 mg pindolol retard.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542036
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  • 11
    Electronic Resource
    Electronic Resource
    Haemodynamic changes in heart failure induced by a new vasodilator tolesmoxide (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 473-477 
    Details
    ISSN: 1432-1041
    Keywords: tolmesoxide ; vasodilators ; heart failure ; haemodynamics ; hypertension ; sulphoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The haemodynamic effect of Tolmesoxide, a new sulphoxide chemically dissimilar from other vasodilators, was investigated in eight patients with chronic heart failure subsequent to ischaemic heart disease and/or hypertension. Tolmesoxide significantly increased the cardiac output and reduced the indices of systemic vascular resistance, the mean pulmonary arterial pressure and left ventricular filling pressure in most patients studied. These changes were observed both as acute and chronic effects. No significant effect on the mean arterial pressure, heart rate or myocardial oxygen supply/demand was observed. Tolmesoxide appeared to be therapeutically potent by both intravenous and oral routes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542041
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  • 12
    Electronic Resource
    Electronic Resource
    Studies on the autonomic nervous system in borderline hypertension (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 285-288 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; plasma adrenaline ; plasma noradrenaline ; isoprenaline response ; noradrenaline response ; salivation ; parasympathetic nervous system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Parameters of the autonomic nervous system were studied in normotensive subjects (NT; standing blood pressure (BP)≤125/85 mmHg) and in subjects with borderline hypertension (BHT; 140/90≤standing BP〈60/100 mmHg). No differences in plasma noradrenaline and adrenaline levels were found between NT and BHT subjects, neither at rest nor during exercise at 75% of maximum work capacity. The dose of noradrenaline required to increase systolic BP by 10 mmHg was significantly higher in NT than in BHT subjects (5.13±0.42 vs 3.50±0.57 µg · min−1). No difference between NT and BHT subjects was found in the dose of isoprenaline required to increase heart rate by 20 beats · min−1 (1.21±0.12 vs 1.09±0.11 µg · min−1). Resting salivary flow was significantly lower in BHT than in NT subjects (0.39±0.06 vs 0.98±0.06 g · min−1), suggesting decreased parasympathetic activity in the former group. The enhanced pressor effect of noradrenaline, together with the decreased parasympathetic activity, could explain the elevated blood pressure and heart rate in subjects with borderline hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00548394
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  • 13
    Electronic Resource
    Electronic Resource
    Effects of a new long-acting beta-blocker bopindolol (LT 31-200) on blood pressure, plasma catecholamines, renin and cholesterol in patients with arterial hypertension (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 491-493 
    Details
    ISSN: 1432-1041
    Keywords: bopindolol ; hypertension ; beta-blocker ; blood pressure ; plasma renin ; plasma catecholamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Bopindolol (LT 31-200), a new, long-acting, non-selective beta-blocker, was given as monotherapy to 13 patients, 12 with essential hypertension and 1 with renovascular hypertension. After a placebo period of 4–6 weeks, bopindolol was given once daily, starting with 1 mg and subsequently increasing at two-weekly intervals to 2 and 4 mg once daily until a diastolic blood pressure⩽90 mmHg was achieved. The effective dose was continued for 12 weeks. In 10 patients plasma levels of renin, noradrenaline, adrenaline and cholesterol were measured during placebo and after 3 months of therapy. Blood pressure and heart rate were lowered significantly during bopindolol treatment. The mean effective dose was 2.2 mg per day. In 10/13 patients a diastolic blood pressure⩽90 mmHg was achieved. Side effects were minimal. Changes in plasma noradrenaline and adrenaline were small and not significant, but renin and cholesterol were significantly reduced. Thus, LT 31-200 is an effective and well tolerated beta-blocker when given in a once daily dosage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609620
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  • 14
    Electronic Resource
    Electronic Resource
    Long-term therapy of arterial hypertension with nifedipine given alone or in combination with a beta-adrenoceptor blocking agent (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 101-103 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; nifedipine ; beta-adrenoceptor blockade ; long-term treatment ; adverse effects ; propranolol ; timolol ; metoprolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of nifedipine during long-term therapy was investigated in 5 patients receiving nifedipine as the sole drug and in 10 patients who had nifedipine in combination with a beta-adrenoceptor blocking drug. Nifedipine monotherapy was problematic because of side-effects and development of resistance to therapy after a few months. In patients who received the combined therapy significant and stable blood pressure reductions were maintained during the whole observation period (12–33 months). However, the occurrence of peripheral oedema in 4 of the patients necessitated the addition of a thiazide diuretic. It is concluded that nifedipine is not a first choice drug for the long-term treatment of arterial hypertension. When given in addition to a beta-blocker it is well tolerated and powerful but fluid retention may occur and if not counteracted by a diuretic it will limit the antihypertensive potential of the drug.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542452
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  • 15
    Electronic Resource
    Electronic Resource
    Acute and long-term hypotensive effects and plasma concentrations of nifedipine in patients with essential hypertension (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 197-201 
    Details
    ISSN: 1432-1041
    Keywords: nifedipine ; hypertension ; low dose ; plasma concentration ; acute and long-term treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The acute and long-term hypotensive effects of low doses of nifedipine, and the correlation between the fall in the blood pressure (BP) and the plasma nifedipine concentration, were investigated in patients with essential hypertension. The oral administration of nifedipine 5 mg rapidly decreased BP from 163±22/101±10 to 127±12/82±9 mmHg (mean±SD; p〈0.001), and increased heart rate from 72±8 to 76±6 beats/min (p〈0.05), plasma renin activity rose from 1.2±0.6 to 1.4±0.8 ng/ml/h (p〈0.05), and plasma nifedipine concentration was 75.6±22.0 ng/ml 30 min after administration (n=7). The nifedipine concentration was significantly correlated both with the fall in BP (r=0.410, p〈0.02, n=31) and the rise in the heart rate (r=0.412, p〈0.02, n=31). Treatment with nifedipine 5 mg t.d.s. alone or in combination either with propranolol 10 mg t.d.s., or thiazide 1 tablet daily, or propranolol and thiazide, controlled BP in 36 patients during the 22 week study period. During the long-term nifedipine therapy, the plasma nifedipine level was significantly correlated with the fall in systolic (r=0.577, p〈0.01, n=20) and diastolic (r=0.595, p〈0.01, n=20) BP. It was concluded that the plasma nifedipine concentration could be correlated with the fall in BP, and that low doses of nifedipine, either as monotherapy or in combination, were effective in the acute and long-term treatment of patients with essential hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00547553
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  • 16
    Electronic Resource
    Electronic Resource
    Antihypertensive mechanism of the diuretic muzolimine in mild renal failure (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 215-220 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; muzolimine ; mild renal functional impairment ; diuretic treatment ; body sodium ; catecholamines ; cardiovascular pressor responsiveness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eighteen patients with mild impairment of renal function (glomerular filtration rate 65±5 ml/min: m±SEM) and hypertension (168/105±6/3 mmHg) were shown on average to have abnormally increased cardiovascular pressor responsiveness to infused norepinephrine (NE; p〈0.05), whereas plasma and urinary NE, exchangeable body sodium and blood-volume did not differ significantly from normal. A slightly increased pressor responsiveness to angiotensin II was associated with a tendency to low plasma renin activity (PRA). Compared to placebo conditions, treatment with the loop-diuretic muzolimine in a mean dose of 35±2 mg/day for six weeks decreased blood-pressure and exchangeable sodium (p〈0.05), and NE pressor responsiveness was restored to normal values, whilst plasma and urinary NE were not significantly changed. This was consistent with improvement of the initially abnormal relationship between NE levels and NE responsiveness factors. In contrast, the pressor dose of angiotensin II and PRA were increased to an approximatively similar extent during muzolimine treatment. These observations suggest that removal of body sodium and a decrease in NE reactivity without an equivalent increase in sympathetic nervous activity may be important complementary factors in the antihypertensive mechanisms of diuretic treatment in patients with mild renal functional impairment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00547556
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  • 17
    Electronic Resource
    Electronic Resource
    Acute effects of prizidilol on blood pressure, heart rate, catecholamines, renin and aldosterone in essential hypertension (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 289-296 
    Details
    ISSN: 1432-1041
    Keywords: prizidilol ; vasodilator ; hypertension ; beta blocker ; plasma renin ; aldosterone ; catecholamines ; acetylator type
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Prizidilol is a new antihypertensive agent reported to possess combined precapillary vasodilator and betareceptor-blocking properties. To clarify the profile of the acute effects of prizidilol in man, a variable dose study was performed in 8 patients with benign essential hypertension. Blood pressure, heart rate, plasma renin activity, aldosterone, plasma and urinary catecholamines and electrolytes were determined at short intervals before and up to 23 h after oral administration of placebo and prizidilol 150, 300 and 600 mg. The 4 studies were performed at weekly intervals according to a Latin square design. Prizidilol produced dose-dependent decreases in supine and upright blood pressure, with an initial change after about 2 h and maximal effects from 4 to 8 h after drug ingestion. Following a high dose of prizidilol, supine mean blood pressure (average 128 mmHg prior to treatment) was normalised (〈107 mmHg) from 3 to 7 h and was still below predose levels 23 h after ingestion. The only reported side effects were postural dizziness in 2 cases (corresponding to a fall in systolic upright blood pressure to 〈95 mmHg) and headache in one case. A biphasic variation in heart rate and plasma renin activity, with an early drop and a subsequent tendency to a slight rise, was observed after an intermediate or high dose of prizidilol. Plasma norepinephrine levels were increased by a high dose of prizidilol, while plasma epinephrine, aldosterone and plasma and urinary electrolytes were not consistently changed. Prizidilol in a single oral dose appeared to be a potent antihypertensive agent. The profile of heart rate and plasma renin point to early dominance of beta-blockade followed by appearance of the concomitant vasodilator properties of prizidilol.
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    URL: http://dx.doi.org/10.1007/BF00613608
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  • 18
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    Effect of spironolactone on systemic blood pressure, limb blood flow and response to sympathetic stimulation in hypertensive patients (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 263-267 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; spironolactone ; hypotensive action ; peripheral circulation ; plethysmography ; handgrip test ; cold pressure test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Since there is only scanty, indirect information about the mechanism of the hypotensive effect of spironolactone, 9 patients with essential hypertension were studied according to a randomised double-blind, cross-over protocol. Spironolactone 100mg b.i.d. and placebo were each given for one month and the following parameters were studied: blood pressure, heart rate, response to cold pressure and hand-grip tests, as well as blood flow in the calf and finger vessels. Flow in the calf and fingers representing muscle and skin arteries, respectively, was measured semicontinuously with an ECG-triggered venous occlusion plethysmograph. After spironolactone there was a significant decrease in the systolic and diastolic blood pressures in the supine, sitting and standing positions; the sitting systolic and diastolic blood pressure decreased by (mean ± SE) 27±4mm Hg (p〈0.001) and 11±4mm Hg (p〈0.02), respectively. No orthostatic response was observed. Heart rate remained unchanged. Blood flow through muscle and skin vessels increased in 6 out of 9 patients, and in these patients calculated vascular resistance in these areas decreased. Spironolactone did not significantly change the response of systemic blood pressure to the handgrip and cold pressure tests. The present data confirm the hypotensive properties of spironolactone and show that this effect is associated with dilatation of muscle and skin arteries in many but not in all the patients. The data do not support the hypothesis that spironolactone decreases the responsiveness of systemic blood pressure to orthosympathetic stimulation.
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    URL: http://dx.doi.org/10.1007/BF00637611
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  • 19
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    Effects of once daily indapamide and pindolol on blood pressure, plasma aldosterone concentration and plasma renin activity in a general practice setting (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 191-196 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; indapamide ; pindolol ; plasma renin activity ; plasma aldosterone concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Sixteen patients with essential hypertension completed a double blind factorial trial comparing the effects of indapamide (2.5 mg daily) and pindolol (10 mg daily) on blood pressure, heart rate, plasma renin activity and plasma aldosterone concentration. There were four randomised test phases of eight weeks each during which patients received indapamide alone, pindolol alone, indapamide plus pindolol and no active treatment (placebo). Blood pressure and heart rate were measured every two weeks. Supine mean arterial pressure fell from 117 mm Hg in the placebo phase to 111 mm Hg in the indapamide phase, 106 mm Hg in the pindolol phase and 103 mm Hg in the combined indapamide plus pindolol phase. Factorial analysis confirmed that the hypotensive effects of the two drugs were additive, without evidence of potentiation or antagonism. Indapamide caused significant reductions in plasma potassium and chloride, and increases in plasma bicarbonate and urate concentrations; it also caused increases in plasma renin activity and aldosterone concentration. These changes are similar to those observed with thiazide diuretics.
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    URL: http://dx.doi.org/10.1007/BF00545213
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  • 20
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    Titration of nadolol in the treatment of hypertension (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 487-489 
    Details
    ISSN: 1432-1041
    Keywords: nadolol ; hypertension ; effective dose range ; compliance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary An open, observer-blind, therapeutic titration trial was carried out in 28 patients with mild or moderate essential hypertension to determine the effective dose range of nadolol given once a day. 11 patients became normotensive (supine diastolic blood pressure 90 mm Hg or below) with 80 mg, 4 with 120 mg and 1 with 160 mg. The largest step in the reduction of blood pressure was achieved with the first dose step of 80 mg, and only a small, non-significant further decrease was obtained with higher dose levels. Thus, nadolol, unlike propranolol, has a narrow effective dose range, and this should permit a brief dose adjustment period, which would be important in improving patient compliance.
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    URL: http://dx.doi.org/10.1007/BF00609619
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  • 21
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    The clinical pharmacology of tolmesoxide (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 93-97 
    Details
    ISSN: 1432-1041
    Keywords: tolmesoxide ; vasodilator ; hypertension ; pharmacokinetics ; haemodynamics ; plasma renin activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The haemodynamic response and pharmacokinetics of single dose oral tolmesoxide were studied at various dose levels in 4 patients with severe hypertension. There was a reproducible fall in mean arterial pressure from baseline of 24.2% and a rise in heart rate of 37.6% following administration of tolmesoxide. The onset of antihypertensive action occurred within 1 h, with a peak effect at 3 h after dosing. The mean duration of action was up to 12.0 h. Tolmesoxide had a mean half-life of 3.0 h. It was rapidly absorbed with a mean peak plasma level occurring at 1.0 h. Plasma levels correlated well with the doses administered. Side-effects included mild nausea, facial flushing and postural symptoms.
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    URL: http://dx.doi.org/10.1007/BF00545961
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  • 22
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    Comparison of labetalol, propranolol and hydralazine in hypertensive out-patients (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 457-460 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; propranolol ; hydralazine ; labetalol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a randomised cross-over trial the combination labetalol/hydrochlorothiazide was compared with the combination of propranolol/hydralazine/hydrochlorothiazide in 34 uncomplicated hypertensive patients, who were not satisfactorily controlled with hydrochlorothiazide 50 mg alone. The elevated diastolic pressure (D.P.) in 27 patients responded satisfactorily to the labetalol schedule and in 28 patients to the propranolol/hydralazine schedule. No difference was found in the rate of decrease of D.P., nor in the disappearance of hypertension — related complaints. Although the duration of the washout between treatments was at least one month, treatment was significantly more efficacious during the second period. Labetalol pre-treatment especially seemed to enhance the effect of subsequent propranolol/hydralazine administration. Side effects due to therapy were rare and were not related to any particular treatment. The median daily dose of labetalol in responders was 600 mg and that of propranolol/hydralazine 120/60 mg (in both therapies hydrochlorothiazide 50 mg was given in addition). Patients showed a slight preference for the labetaol medication. It is concluded that labetalol/hydrochlorothiazide and propranolol/hydralazine/hydrochlorothiazide are equally satisfactory in the treatment of uncomplicated hypertension.
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    URL: http://dx.doi.org/10.1007/BF00542038
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  • 23
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    Ticrynafen and hydrochlorothiazide a comparison in hypertensive patients with renal impairment (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 203-206 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; ticrynafen ; hydrochlorothiazide ; renal impairment ; uricosuria ; diuretic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The efficacy of ticrynafen in the treatment of hypertension in patients with moderate renal impairment was compared with that of hydrochlorothiazide in a randomised, double-blind crossover trial in eleven subjects with renal insufficiency. Significant reductions in blood pressure occurred with both treatments, with the maximum responses occurring at different time intervals and to different degrees in individual patients. Thus, although ticrynafen caused a significant reduction in blood pressure in this group of hypertensive patients with renal insufficiency, it was not consistently different from that which could be achieved with hydrochlorothiazide. Ticrynafen also significantly reduced the serum uric acid concentration, compared with a significant rise with hydrochlorothiazide. No major biochemical abnormalities or side-effects were encountered in any subject. Thus, in these patients with renal insufficiency, ticrynafen still demonstrated a uricosuric effect as well as a useful anti-hypertensive action.
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    URL: http://dx.doi.org/10.1007/BF00545215
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  • 24
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    Clinical evaluation of labetalol alone and combined with chlorthalidone in essential hypertension: A double-blind multicentre controlled study (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 289-293 
    Details
    ISSN: 1432-1041
    Keywords: labetalol ; chlorthalidone ; hypertension ; fixed combination ; antihypertensive therapy ; side effects ; multicentre study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a multicentre, double-blind, crossover, placebo-controlled study, the antihypertensive effect of labetalol 100 mg and chlorthalidone 10 mg, given alone or in combination, has been assessed in 32 hypertensive patients. The combination had a greater effect in reducing blood pressure than did its separate components. This was particularly evident after exercise. Heart rate increased during chlorthalidone therapy, decreased during labetalol therapy, and a summation effect was observed during treatment with the combination. In most cases additivity was observed, as no interaction between the single components was observed, except for heart rate after exercise, and for diastolic blood pressure in the upright position. No interaction was observed either in the biochemical indices or in the clinical side-effects.
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    URL: http://dx.doi.org/10.1007/BF00548395
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  • 25
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    Effects of treatment with nifedipine and metoprolol in essential hypertension (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 389-390 
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    ISSN: 1432-1041
    Keywords: nifedipine ; metoprolol ; hypertension ; calcium antagonist ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a double-blind trial 26 patients with essential hypertension were treated with nifedipine or placebo for 8 weeks, following a 4-week run-in place-bo period in all patients. The daily dosage of nifedipine during this phase was 10mg 3 times daily. Metoprolol was then added to the therapeutic regimen of both groups for a further 12 weeks. Both nifedipine and metoprolol used as mono-therapy caused statistically significant reductions of arterial pressure. The addition of metoprolol to nifedipine tended to reduce blood pressure further, but blood pressures were not significantly lower than during nifedipine mono-therapy. Side-effects were few and only two patients had to be withdrawn during active therapy, one for headaches during nifedipine therapy, and another for asthma during metoprolol treatment. Combined therapy with a beta-adrenoceptor blocking agent, such as metoprolol, and a calcium antagonist with vasodilating properties, such as nifedipine, offers a theoretically interesting approach in the treatment of hypertension, even though the practical outcome in the present study probably suffered from an inadequate dose of nifedipine during the period of combined therapy.
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    URL: http://dx.doi.org/10.1007/BF00542324
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  • 26
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    Penbutolol (Hoe 893 d) in primary hypertension (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 95-99 
    Details
    ISSN: 1432-1041
    Keywords: penbutolol ; hypertension ; primary hypertension ; blood pressure response ; plasma concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Penbutolol (Hoe 893 d), a long-acting non-selective beta-adrenoceptor blocking agent, was given once daily to 23 patients with primary hypertension, WHO Stages I–II. The dose (50–100 mg) needed to achieve the therapeutic goal, i.e. supine diastolic BP〈95 mm Hg, was titrated individually. On a daily dose of penbutolol 83±19 mg (mean±SD) blood pressure (BP, mean±SD) fell from 180±21/112±8 mmHg on placebo to 154±25/94±14 mmHg. 18 patients who reached the therapeutic goal (responders) continued in a double blind, cross-over study versus placebo, during which the supine BP fell on average 20/10 mmHg on the same dose of penbutolol, and 2/1 mmHg on placebo. Plasma concentrations (mean±SD) of free 0.10±0.07 µg/ml) and total (2.02±1.39 µg/ml) penbutolol did not differ between responders and nonresponders, and were not correlated with the fall in BP. Side effects were mild and mostly well tolerated. One patient developed dermatitis and another an elevation of liver enzymes.
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    URL: http://dx.doi.org/10.1007/BF00542451
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  • 27
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    In vitro and in vivo down-regulation of human plateletα 2-adrenoceptors by clonidine (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 403-409 
    Details
    ISSN: 1432-1041
    Keywords: alpha-2-adrenoceptors ; hypertension ; clonidine ; human platelets ; 3H-yohimbine binding ; receptor regulation ; clonidine withdrawal ; desensitization ; GTP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of clonidine on the number ofα 2-adrenoceptors in human platelet membranes, determined by3H-yohimbine binding, was investigatedin vitro andin vivo. Incubation of platelet membranes with clonidine (1–100 µM) for 16 h at 25 °C led to a concentration-dependent decrease in the number of3H-yohimbine binding sites of 10–25%; the affinity of3H-yohimbine to the sites was not changed (KD approximately 3–4 nM). In such “desensitized” membranes, inhibition of3H-yohimbine binding by clonidine resulted in steep, monophasic displacement curves, which in comparison to the curves from control membranes (IC50 for clonidine 90 nM), were shifted to the right (IC50: 321 nM) and were not affected by 10−4M guanosine-5′-triphosphate (GTP). Treatment of 3 hypertensive patients with clonidine (3×150 µg/d for 7 days) reduced blood pressure and heart rate. Simultaneously, both3H-yohimbine binding sites on platelet membranes and plasma catecholamine levels decreased within three days and remained at a reduced level during treatment. After abrupt cessation of clonidine treatment, blood pressure, heart rate and plasma catecholamines rapidly increased, reaching values after two days similar to or higher than those before treatment.3H-yohimbine binding sites, however, initially decreased further before returning to control values. In platelet membranes derived from hypertensive patients treated with clonidine for at least three weeks, GTP (10−4M) had no influence on inhibition of3H-yohimbine binding by (—)-adrenaline and clonidine. It is concluded that clonidine desensitizesα 2-adrenoceptors in human platelet membranesin vitro andin vivo. An important step in the desensitization process is the uncoupling of receptor occupancy by agonists and adenylate cyclase activity, as indicated by loss of the regulatory activity of GTP on desensitized membranes. The clonidine withdrawal syndrome may be caused by enhanced release of endogenous catecholamines not adequately regulated by presynapticα 2-adrenoceptors, which have become subsensitive after chronic clonidine treatment.
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    URL: http://dx.doi.org/10.1007/BF00605989
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  • 28
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    Comparison of two doses of betaxolol and placebo in hypertension: A randomized, double-blind cross-over trial (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 491-494 
    Details
    ISSN: 1432-1041
    Keywords: betaxolol ; hypertension ; double-blind trial ; cross-over trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Betaxolol is a cardioselective beta-blocker, which has a bioavailability of 90% and a T1/2 of 20 h. A four group, cross-over double-blind trial was conducted to select between betaxolol 20 mg and 40 mg for long term trials. 60 patients were allocated randomly to one of the sequences placebo-20 mg, 20 mg-placebo, placebo-40 mg and 40 mg-placebo, each treatment lasting for 2 weeks. Groups were homogenous for baseline diastolic blood pressure (DBP), age and male/female ratio, and were slightly unbalanced for weight. A two-way ANOVA (3 treatments, 2 sequences) showed no treatment-sequence interaction nor sequence effect. The mean reduction in DBP was 14.2±1.8 mm Hg following 20 mg and 18.0±1.8 following 40 mg betaxolol, and 4.0±1.2 mm Hg during placebo (p〈0.001). Age, weight, baseline DBP and duration of hypertension did not influence the treatment effect. The 95% confidence intervals of the reduction in DBP were 10.4–17.9 for 20 mg and 14.3–21.6 mm Hg for betaxolol 40 mg. Aiming at a mean reduction to 90 mm Hg, betaxolol 20 mg would appear to be adequate in similar patient populations.
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  • 29
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    Prizidilol (SK & F 92657), a new vasodilator with beta-blocking properties in the treatment of essential hypertension (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 411-415 
    Details
    ISSN: 1432-1041
    Keywords: prizidilol ; hypertension ; side effects ; chronic treatment ; antihypertensive effect ; anaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of a new vasodilator with betablocking properties (SK & F 92657) was investigated in 10 patients with mild to moderate essential hypertension. After a mean treatment period of 26,5 weeks (6,5–49 weeks) blood pressure was significantly reduced, from 168±22/106±6 mmHg to 144±19/94±12 mmHg (p〈0.05 and 0.025). The mean dose was 410 mg (100–700 mg). Heart rate decreased slightly from 77±12 to 70±8 beats/min. Plasma renin activity and plasma aldosterone showed only minor changes. Nausea, heavy dreams, facial and hand flushing and mild depression were reported as side effects. In most patients the symptoms disappeared without reduction in the dose. In one patient anaemia developed after 7 weeks and treatment with prizidilol was stopped. A slight but statistically significant decrease in haemoglobin concentration of 1.1±0.6 g/dl was observed in 5 of the 10 patients (p〈0.02). Thus, a mean dose of prizidilol of 410±242 mg/day had a mean blood pressure lowering effect of 24/12 mmHg. In 7 of the 10 patients (70%) diastolic blood pressure could be reduced to 95 mmHg or less. However, the observed haematological side-effects should be carefully monitored in further studies and may limit the clinical use of prizidilol.
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    URL: http://dx.doi.org/10.1007/BF00605990
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  • 30
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    The use of long-acting propranolol (‘Inderal’ LA) in the management of elderly hypertensive patients (1982)
    Springer
    European journal of clinical pharmacology 22 (1982), S. 379-381 
    Details
    ISSN: 1432-1041
    Keywords: propranolol ; hypertension ; elderly patients ; long-acting propranolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Fifteen elderly patients whose hypertension was controlled by conventional propranolol 80 mg twice a day had their medication changed to one capsule of ‘Inderal’ LA1 (160 mg) daily. The blood pressure, heart rate and propranolol concentrations were measured at various time points when the patients were receiving the conventional preparation and these assessments were repeated when the long-acting preparation was administered. Although the heart rate was lower with conventional propranolol than with ‘Inderal’ LA there was no significant difference in the blood pressure levels. The mean peak blood level of propranolol was, however, significantly lower with ‘Inderal’ LA compared with conventional propranolol and occurred later. At 12 h the plasma propranolol levels were higher after ‘Inderal’ LA than following the intake of conventional propranolol (p〈0.01); there was no difference in the plasma levels at 24 h. The area under the concentration time curve was significantly higher on conventional propranolol. Compared with published data, the plasma levels were higher than those in younger patients. ‘Inderal’ LA was well tolerated and side effects were minimal.
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    URL: http://dx.doi.org/10.1007/BF00542538
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  • 31
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    Within patient comparison of prazosin and UK-33,274. A new alpha-adrenoceptor-antagonist (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 397-401 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; prazosin ; alpha-adrenoceptors ; alpha-blocking drugs ; UK-33,274
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eleven patients with uncomplicated essential hypertension received increasing single daily doses of UK-33,274, a new alpha-1 adrenoceptor antagonist, and prazosin for 4 days, in a open cross-over study. Doses were increased until a satifactory blood pressure response was obtained. Average doses reached were 4.5 mg for UK-33,274 and 2.4 mg for prazosin. The maximum effect of the two drugs on standing blood pressure was similar, but prazosin was more effective in the supine position. Both drugs had a greater effect on standing than on supine blood pressure. UK-33,274 caused a consistent increase in heart rate while prazosin did not. Whereas there was no clear difference between the two compounds in the duration of the reduction in blood pressure the onset of action was more gradual for UK-33,274. The incidence of side-effects was similar for both drugs. The data suggest that UK-33,274 is less effective than prazosin in reducing blood pressure.
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    URL: http://dx.doi.org/10.1007/BF00605988
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  • 32
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    Comparative evaluation of the new vasodilator carprazidil and minoxidil in the treatment of moderate to severe hypertension (1982)
    Springer
    European journal of clinical pharmacology 23 (1982), S. 483-489 
    Details
    ISSN: 1432-1041
    Keywords: carprazidil ; minoxidil ; hypertension ; catecholamines ; renin ; aldosterone ; blood volume ; hypertrichosis ; side effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The efficacy and side effects of the new vasodilator carprazidil and the established vasodilator minoxidil were compared in 18 hypertensive patients inadequately controlled by 2 to 4 conventional drugs; the latter included diuretics, beta-blockers and/or sympatholytics and, in half the cases, vasodilators, such as hydralazine, diazoxide or the postsynaptic alpha-blocker prazosin. The vasodilators were withdrawn and, using a crossover design all patients received carprazidil (mean final dose 88 mg) and minoxidil (20 mg) for an average period of 5 to 6 months. The effects of the 2 agents appeared to be qualitatively and quantitatively similar. Both tended to cause sodium retention and an increase in heart rate, which required an increased dose of diuretic in one third of the cases or of a beta-blocker in a quarter. With this approach mean body weight and blood volume were not altered in the established phase of carprazidil or minoxidil treatment; heart rate and plasma norepinephrine tended to be only minimally increased, plasma renin was slightly increased, and plasma aldosterone and epinephrine were largely unchanged. Supine and upright blood pressure were reduced from initial values of 189/113 and 167/113 mm Hg, to 149/95 and 138/95 mm Hg (−18 and −17%), respectively, during carprazidil, and to 154/95 and 141/96 mm Hg (−17 and −15%) during minoxidil therapy. Hypertrichosis occurred with both agents in almost all patients, and limits their more prolonged use in females. No adverse side effects on haematological parameters, liver or renal function were observed, nor was antinuclear antibody detected. It is concluded that carprazidil and minoxidil are equivalent vasodilator agents in the treatment of severe hypertension, particularly in males.
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  • 33
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    Ultrastructure of the cyanobacterium,Mastigocladus laminosus (1982)
    Springer
    Archives of microbiology 133 (1982), S. 11-19 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the thermophilic cyanobacteriumMastigocladus laminosus were examined by scanning and transmission electron microscopy. Mature cultures consisted of relatively old, wide filaments that branched frequently to form younger, thinner filaments. The cells of the younger filaments had a consistently cylindrical morphology, while those of older filaments were rounded and pleomorphic. The internal ultrastructure of the cells depended somewhat on their age. As young cells became larger and wider, their thylakoids underwent slight rearrangement and spread out toward the center of the cytoplasm. Polyphosphate bodies, carboxysomes (polyhedral bodies), and lipid-body-like structures increased in number as the cells aged, but ribosomes and cyanophycin granules were depleted. Cell division involved septum formation followed by ingrowth of the outer membrane and sheath. Cells in older filaments were separated from each other by a complete layer of sheath material. Septum formation in older cells was also seen to occur parallel to the long axis of the filament, thereby confirming that true branching took place.
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  • 34
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    Effects of metronidazole on growth, chloroplast structure and differentiation in gametophytes ofAnemia phyllitidis L. Sw. (1982)
    Springer
    Protoplasma 113 (1982), S. 144-149 
    Details
    ISSN: 1615-6102
    Keywords: Anemia phyllitidis ; Chloroplast ; Gametophyte ; Metronidazole ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Metronidazole inhibits cell division in gametophytes of the fernAnemia phyllitidis without changing morphogenetic patterns. Simultaneously the sensitivity of the prothallia against gibberellins which substitute for the natural sexual pheromone “antheridiogen A”, is increased. The inhibition of cell division is accompanied by a loss of chlorophyll and by severe changes in the ultra-structure of the chloroplasts.
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    Nuclear and nucleolar inclusions in root tip ofBrassica napus L. (1982)
    Springer
    Protoplasma 113 (1982), S. 189-192 
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    ISSN: 1615-6102
    Keywords: Brassica napus ; Membrane ; Nucleolus ; Nucleus ; Ultrastructure ; Vacuole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Vacuole-like structures were found in the nuclei of root tip cells ofBrassica napus. The cells containing the unusual nuclear inclusions were found to be adjacent to zones of degenerating cells. Such groups of cells occurred irregularly in the meristematic regions of the young root tips. The possibility that they represent changes which have occurred in old seeds is discussed. The “vacuole-like” structures seen in the cells adjacent to the degenerating zones were bounded by a membranous layer 12 nm thick. This is thicker than most cellular membranes. The “vacuoles” frequently contained inclusions and showed similarities to protein bodies reported elsewhere. The structures are thought to represent rearrangements of cell products which may have accumulated through an imbalance of metabolism in consequence of the imminent cell degeneration.
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    Hyphal tip ultrastructure ofAspergillus nidulans andAspergillus giganteus and possible implications of woronin bodies close to the hyphal apex of the latter species (1982)
    Springer
    Protoplasma 113 (1982), S. 209-213 
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    ISSN: 1615-6102
    Keywords: Aspergillus nidulans ; Aspergillus giganteus ; Hyphal apex ; Ultrastructure ; Woronin body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hyphal tip ultrastructure ofAspergillus nidulans andAspergillus giganteus indicates that their apical organization is very similar to that found in other filamentous fungi. Both species have an area immediately behind the hyphal apex free of all large organelles and containing a high concentration of vesicles. InA. giganteus only one size class of vesicle is clearly evident, with a mean diameter of 72 nm. InA. nidulans two size classes of vesicle were found, with mean diameters of 75 nm and 31 nm. A Spitzenkörper is evident inA. nidulans as an area very close to the tip containing only the smaller vesicles. InA. giganteus one or more apparently mature Woronin bodies were found within the first 1 μm of some hyphal apices. The possible significance of their presence is discussed.
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    Ultrastructure of meiosis in the mossRhynchostegium serrulatum I. Prophasic microtubules and spindle dynamics (1982)
    Springer
    Protoplasma 110 (1982), S. 23-33 
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    ISSN: 1615-6102
    Keywords: Meiosis ; Microtubules ; Polarity ; Ultrastructure ; Mosses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An extensive system of microtubules develops during meiotic prophase in the mossRhynchostegium serrulatum (Hedw.)Jaeg. &Sauerb. Development of the cytoskeleton can be traced to early prophase when the nucleus is acentric and the single plastid divides into four plastids. The cytoskeletal microtubules are associated with equidistant positioning of the four plastids at the distal tetrad poles and with migration of the nucleus to a central position in the sporocyte. The cytoskeleton, which interconnects plastids and encloses the nucleus, contributes to the establishment of moss sporocyte polarity. Just prior to metaphase I evidence of the prophase cytoskeleton is lost as the bipolar metaphase I spindle develops in association with discrete polar organizers located in opposite cleavage furrows between plastids.
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    Ultrastructural localization of polysaccharides in the motile diatomNavicula cuspidata (1982)
    Springer
    Protoplasma 113 (1982), S. 10-22 
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    ISSN: 1615-6102
    Keywords: Diatom ; Motility ; Mucopolysaccharide ; Secretion ; Staining ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Generation of movement in benthic diatoms is thought to be intimately associated with secretion at the raphe, a slit in the silica cell wall. The presence and distribution of extracellular substances and their source was investigated cytochemically by transmission electron microscopy. Extracellular material, possibly-acid mucopolysaccharide, was observed consistently within the entire length of the raphe of both valves and also as a sheath enveloping the silica frustule. Such quantities of extracellular material are absent in conventionally fixed motile diatoms. Numerous cytoplasmic vesicles, with fibrillar contents, distributed peripherally but concentrated along the raphe and at the cell poles, react strongly with a polysaccharide specific stain; their distribution in the cell and polysaccharide content suggest these may be the source of raphe and sheath material. Results support the most recent theories on the mechanism of locomotion in outline only; the details cannot be clarified. Localization procedures using alcian blue and silver staining of peroxidised sections are discussed briefly.
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    Isolation and ultrastructural identification of membranes from the fungusGilbertella persicaria (1982)
    Springer
    Protoplasma 111 (1982), S. 87-106 
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    ISSN: 1615-6102
    Keywords: Fungi ; Gilbertella persicaria ; Membranes ; Mitochondria ; Organelle isolation ; Plasma membrane ; Ultrastructure ; Vacuoles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Methods are described for isolating and identifying subcellular membranes from walled hyphae ofGilbertella persicaria. Differences in thickness and symmetry of membranes and in contents of vesicles were used to distinguish different types of membranes. Mitochondria, vacuoles, plasma membrane, and vesicles with attached ribosomes from homogenized germlings equilibrated at the 1.2/1.4 M interface in discontinuous sucrose gradients. Accelerated flotation in centrifuged Ficol-sucrose gradients resulted in the additional separation of the mixed membranes into three fractions: one contained predominantly intact mitochondria, another was composed of vacuoles and vesicles coated with ribosomes, and a third was enriched in plasma membranes. Based upon morphometric analysis, these fractions contained 92% mitochondria, 53% vacuoles, and 89% plasma membranes, respectively. The source of vesicles coated with ribosomes was investigated since rapidly growing hyphae ofG. persicaria contained little rough endoplasmic reticulum as compared with other classes of membranes. Reconstruction from electron micrographs of mitochondrial fragmentation and vesiculation suggested that most of the ribosome-coated vesicles originated from disrupted mitochondria rather than from rough endoplasmic reticulum. The study demonstrates the utility of ultrastructural markers to identify membranesin vitro independent of, or as an adjunct to, cytochemical and biochemical markers.
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    A light and electron microscopic study of stigmas inAneilema andCommelina species (Commelinaceae) (1982)
    Springer
    Protoplasma 112 (1982), S. 26-36 
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    ISSN: 1615-6102
    Keywords: Aneilema ; Commelina ; Cytochemistry ; Evolution ; Papillae ; Pollination ; Secretion ; Stigmas ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The stigmas of species inAneilema andCommelina are trifid and comprise elongate papillae. Progressive degeneration of papular cells is observed in stigmas from open flowers and at anthesis papillae may be moribund and collapsed. Fluid emanating from the hollow style flows onto the surface through ruptures in the cuticle at the interpapillar junctions into the interstices at maturity. This secretion stains positively for protein. Stigmas are of the “wet” type. The cuticle overlying the papillar cells is ridged and at the final stages prior to flowering this cuticle becomes detached from the underlying cellulosic wall. The sub-cuticular space so formed is filled with secretion. InAneilema species detachment of cuticle is at the papillar tip and along the lateral walls. InCommelina species the anticlinal walls of adjacent papillae are strongly attached for much of their length and thus detachment of cuticle is restricted to the papillar tip. The cell wall at the tip in both genera may proliferate forming a rudimentary transfer-cell type wall. The secretion is considered to be produced by the papillar cells. It is PAS positive but fails to stain for protein and in both the light and electron microscopes appears heterogenous. Pollen attachment, hydration, germination and early tube growth are very rapid following self-pollination, the pollen tubes entering the neck of the style within ten minutes of attachment. A unique character combination involving pollen and stigmas in these genera indicates a monophyletic origin.
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    Microcyst formation in the plasmodial slime moldDidymium iridis (1982)
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    Protoplasma 112 (1982), S. 81-91 
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    ISSN: 1615-6102
    Keywords: Didymium iridis ; Microcyst-encystment ; Ultrastructure ; Differentiation ; Myxomycete
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Myxamoebae ofDidymium iridis were removed from the bacterial food source and induced to encyst by transfer to 10 mM phosphate buffer. After 24 hours of induction approximately 90% of the myxamoebae had differentiated into microcysts. The kinetics of encystment were not significantly affected by pH or osmolarity of the encystment medium. Early stages of encystment were distinguished by the appearance of autophagic vacuoles and an extracellular “slime-like” sheath. The outer wall layer, consisting of dense fibrils, was unevenly deposited after 4 hours. An electron-lucent, second wall layer appeared between 5–10 hours followed by a densely packed, third wall layer adjacent to the plasma membrane. Wall formation appeared to involve smooth-membraned vesicles of possible Golgi origin. The vesicle contents and outer wall layer reacted with the periodic acid-silver methenamine stain for polysaccharide. The density of intramembrane particles of the protoplasmic fracture face increased during encystment with a gradual formation of aggregates of particles.
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    Tentacle contraction and ultrastructure inDiscophrya collini: The response to cations (1982)
    Springer
    Protoplasma 112 (1982), S. 92-100 
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    ISSN: 1615-6102
    Keywords: Discophrya ; Tentacle contraction ; Cations ; Calcium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Discophrya collini is a suctorian protozoan with contractile tentacles containing a microtubule-lined canal and microfilaments. The effects of a range of cations on tentacle contraction and ultrastructure have been determined. Treatment with 80 mM CaCl2 and 95 mM MgCl2 causes contraction to 28% and 57% of the control length respectively. Re-extension takes over 4 hours in the culture medium, but CaCl2-treated tentacles are re-extended after a 5 minutes treatment with 10−2 M EDTA or 5 × 10−3 M EGTA. CuCl2 causes a significant contraction at 10−5 M (to 77%); LaCl3 at 10−4 M (to 65%); ZnCl2 at 10−2 M (to 65%), but BaCl2, CoCl2, MnCl2, NiCl2, and SrCl2 cause significant changes only at 10−1 M. The cytoplasm of CaCl2-treated cells contains two forms of membraneous structures when viewed in TEM; that of MgCl2-treated cells reveals granular areas of medium electron density. None of these features are seen in control cells. The microtubules of the tentacle canal appear to be intact upon its retraction into the cell with no change occurring in the numbers or relative positions of the microtubules. The tentacle cortex is wrinkled. It is suggested from this and previous work that tentacle contraction may be mediated by a microfilament-based mechanism, and that calcium may be involved.
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    Cross-linking bridges associated with the microbody-lipid globule complex inChytriomyces aureus andChytriomyces hyalinus (1982)
    Springer
    Protoplasma 112 (1982), S. 181-188 
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    ISSN: 1615-6102
    Keywords: Fungus ; Zoospore ; Ultrastructure ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Determining how the orientation and association among organelles are maintained within zoospores of theChytridiales is important to understanding the control of zoospore motility. Zoospores of the aquatic fungi,Chytriomyces aureus andC. hyalinus, contain microbody-lipid globule complexes with an elongate microbody adjacent to the portion of a lipid globule facing the cell's interior and a fenestrated cisterna (the rumposome) opposed to the surface of the lipid globule toward the plasma membrane. Mitochondria are intimately associated with the microbody. Electron microscopy of the microbody-lipid globule complex fixed in glutaraldehyde and osmium tetroxide, with or without tannic acid, reveals cross-linking bridges connecting the rumposome to the plasma membrane, to the microbody, and to microtubules of the rootlet extending from the kinetosome. It is concluded that these bridges are responsible, at least in part, for the consistent location of the microbody-lipid globule complex in the zoospore body. The possible role of the rumposome as a receptor organelle is discussed.
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    Rapidly-secreting, cultured oat cells serve as a model system for the study of cellular exocytosis. Characterization of cells and isolated secretory vesicles (1982)
    Springer
    Protoplasma 112 (1982), S. 196-204 
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    ISSN: 1615-6102
    Keywords: Secretion ; Vesicles ; Ultrastructure ; Cultured cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Callus-derived suspension cultures of oats dramatically increase the viscosity of the culture media after one month in culture. Colorimetric assays for sugars and protein, as well as measurements of viscosity, suggest that the released material is a long-chain polysaccharide, probably a pectinaceous substance. These cells grow slowly in liquid culture, yet despite their low cell density, they are able to increase the viscosity of the media several fold within seven days after media transfer. Ultrastructural observations show that oat cells have features common to actively-secreting cells; especially evident are numerous dictyosomes with hypertrophied cisternae. Using a combination of filtering and centrifugation techniques we were able to recover large numbers of intact secretory vesicles. The interior of the vesicles stain with periodic acid-silver hexamine, and colormetric analysis of the vesicle pellet for total sugars confirms the presence of polysaccharides in this vesicle fraction. Because of the uniformity of these cells, the high rate of secretion, and the accessability of a large vesicle population, this culture system is'a useful model for studying the secretory process in plant cells.
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    Effect of adaptation to high altitude hypoxia on catecholamine metabolism in spontaneously hypertensive rats (1982)
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    Bulletin of experimental biology and medicine 93 (1982), S. 24-26 
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    ISSN: 1573-8221
    Keywords: catecholamines ; hypertension ; hypoxia ; adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Hemodynamic response of normotensive and hypertensive rats to prostaglandins and indomethacin (1982)
    Springer
    Bulletin of experimental biology and medicine 94 (1982), S. 1063-1066 
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    ISSN: 1573-8221
    Keywords: prostaglandins ; hemodynamics ; baroreflex ; hypotension ; hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1007/BF00830713
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    Primary productivity and nutrients in the sediment retention basin of Lake Monroe (1982)
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    Hydrobiologia 87 (1982), S. 193-200 
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    ISSN: 1573-5117
    Keywords: primary productivity ; phosphorus ; EDTA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Monroe is the largest body of water in Indiana with a daily mean productivity of 220 mg · C · m−2 · day−1 in an observed range from 26 to 714 m · C · M−2 day−1. It is a medium soft reservoir; the acid combining capacity varies from 0.28 to 0.71 meq · l−1 with a mean slightly above 0.5 meq · l−1. The results of diurnal changes in major nutrients, the C, N, and P ratios, and bioassay experiments indicated that phosphorus is the major limiting nutrient on algal photosynthesis in this lake. Surface photo-inhibition may be used to indicate the sufficiency of light for the species of algae in the water. The low productivity in December, January, February, and early March can be attributed to light limitation due to low water transparency.
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    Epilimnetic nutrient loading by metalimnetic erosion and resultant algal responses in Lake Waramaug, Connecticut (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 501-510 
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    ISSN: 1573-5117
    Keywords: phosphorus ; nutrient cycling ; stratification ; epilimnion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphorus regeneration from lake sediments, and subsequent migration to trophogenic surface water, significantly contributes to the lake nutrient budgets and algal bloom conditions in some lake types. Decomposition of organic matter in deep water and sediments results in the accumulation of regenerated nutrients, alternate electron acceptors (reduced products of anaerobic respiration = COD), carbon dioxide, and depletion of dissolved oxygen (electron acceptor in aerobic respiration). Thermal stratification creates spatial segregation of trophogenic and tropholytic environments in the lake, resulting in gradients between sediments, hypolimnion, and the epilimnion. Exchange of oxygen, nutrients, and reduced alternate electron acceptors between the hypolimnion and epilimnion affects the productivity of a lake. Secchi depth, temperature, and dissolved oxygen profiles were determined twice each week from May 1980 to October 1980 at each of five lake stations. Nutrient concentration profiles, including total soluble and total phosphorus, ammonium-N, nitrate, soluble Kjeldahl, and total Kjeldahl nitrogen were determined twice each month. Epilimnetic algal samples were collected twice each week using Kemmerer and water column ‘straw’ amplers. Cell counts of total, green, bluegreen, and diatom algae groups were made. Three methods were used to describe hypolimnetic-epilimnetic exchange, including coefficients of eddy diffusion (based on lake heat budget), a graphical method of defining thermocline location, and relative thermal resistance to mixing (RTRM, based on density differences). All three methods yeilded comparable estimates of net seasonal transport. The graphical and RTRM methods described events occurring at shorter intervals (greater resolution). We find general agreement between the three methods of describing hypolimnetic-epilimnetic transport. The frequency of sampling resulted in increased resolution of thermal profiles (in time), allowing accurate estimation of short-term nutrient flux into epilimnetic waters. An algal bloom event occurred 5 to 12 days following erosion of the top of the metalimnion to below the aerobic-anaerobic interface. The lag time to peak algal concentration, following such events, decreased through the summer (June = 12 days, September = 5 days)
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    Acidified lakes: sediment treatment with sodium carbonate — a remedy? (1982)
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    Hydrobiologia 91-92 (1982), S. 537-547 
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    ISSN: 1573-5117
    Keywords: lake acidification ; neutralization ; buffer capacity ; liming ; cation exchange ; humic sediment ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Until now, additions of lime have been used to restore the buffering capacity of acidified lakes, but an alternative method which is more effective in the treatment of lakes with organogenic sediments has recently been applied in a full-scale experiment. The method, called CONTRACID, is based on the cation exchange properties of lake sediment. A sodium carbonate (soda ash) solution is injected into the sediment (by a harrow), so that the sediment becomes sodium stocked. A reverse exchange occurs during subsequent acidification. Liming has a limited effect on humic lakes, since Ca-humates have a reduced reverse exchange ability and also the lime, which remains undissolved, is rendered inactive. Ionic exchange processes and nutrient transport were studied in water/sediment cores and in situ enclosures after additions of soda ash-, lye- and lime solutions with subsequent re-acidification. Sodium carbonate additions in laboratory systems resulted in a sorption to the sediment of 42–62% of the added sodium ions (5 eq m−2) and a release of 14–78 mg Pm−2 sediment. Similar results were obtained in the enclosures where phosphorus release stimulated algal growth. Sediment pH, elevated by the sodium base addition, was lowered by re-acidification. Limed systems released no phosphorus and only about 25% of the added lime remained active for future neutralization. With the injection of the sodium carbonate solution into the sediment, only about 12% of the added sodium was recovered in lake water by spring circulation. Lake water alkalinity was then 0.12 meq l−1 and pH 6.7. Total phosphorus had been raised by 0.007 mg P l−1 causing an increase in phytoplankton biomass. Observations indicate that manipulations of acidic lake sediment according to the CONTRACID method create a long-lasting neutralizing capacity and a biological stimulation (through phosphorus release), which makes the method an attractive alternative to frequent liming.
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    Lake Trehörningen restoration project. Changes in water quality after sediment dredging (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 549-558 
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    ISSN: 1573-5117
    Keywords: lake restoration ; sediment dredging ; nitrogen ; phosphorus ; algal assays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An increased load of domestic wastewater to Lake Trehörningen induced oxygen-poor water conditions and the development of a reduced sulphide-rich sediment layer. Severely polluted, the lake did not recover, even after advanced wastewater treatment and sewage diversion. Restoration measures with suction dredging and macrophyte elimination were applied in 1975 and 1976. The loose topmost sediment was pumped into an embanked and overgrown bay which was used as a settling pond. The activities also included a restoration of the shorelines. This project is the largest restoration programme carried out in Sweden on a single lake, corresponding to a cost of about US $2 000 000. The restoration of Lake Trehörningen was followed by a highly intensive research programme which included water chemistry and algal assays. The concentrations of phosphate and total phosphorus decreased by 73 and 50% respectively, as summer average values, two years after the restoration. However, the concentrations of phosphorus are still too high to permit this element to act as a prime algal growth-limiting nutrient. The algal biomass has also remained at the same magnitude as before the restoration. Nitrate-N concentrations showed a tenfold increase, based on average values for the summer period. However, based on the results of the algal assays, a rapid and marked response was obvious, with a drastic decline in the algal growth potential. In addition, the water quality of the tributaries was frequently of an objectionable character (0.1–0.2 g P m−3). The nutrient loading from these sources exceeds the critical level for the lake, and measures have now been carried out to treat all the inflowing waters for the removal of phosphorus.
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    Sedimentation rates in a Swiss-Italian lake measured with sediment traps (1982)
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    Hydrobiologia 91-92 (1982), S. 603-610 
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    ISSN: 1573-5117
    Keywords: phytoplankton ; tripton ; phosphorus ; mineralization ; regeneration and diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tripton sedimentation was investigated in the eutrophic Lake Lugano (Ponte Tresa basin) from October 1979 to October 1980. The annual amount of tripton collected was 748 g · m−2 · y−1. Phosphorus, nitrogen and organic carbon fluxes into the hypolimnion were estimated to be 1.9, 16.2 and 121 g · m−2y−1 respectively. Mineralization rates into the trophogenic layer varied from 11% to 19% per day during summer stratification. The regeneration processes contribute about 60% of the calculated P deficit in the epilimnion. The tripton is decomposed mostly in the metalimnion, out of the euphotic zone; from here the phosphorus is carried back to the overlying waters by diffusion processes.
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    Colonisation par les micro-organismes, evolution chimique des feuilles de différentes espèces d'arbres (peuplier, aulne, myrique) dans des eaux oligotrophes du Bouclier canadien et incidence sur leur utilisation par les macro-invertébrés (1982)
    Springer
    Hydrobiologia 96 (1982), S. 65-75 
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    ISSN: 1573-5117
    Keywords: leaf-conditioning ; microorganisms ; nitrogen ; carbon ; phosphorus ; Alnus rugosa ; Populus tremuloides ; Myrica gale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Myrica gale, Alnus rugosa and Populus tremuloides leaves were incubated ‘in situ’ in the oligotrophic acid waters of the Canadian Shield (James Bay, Quebec) in order to follow microorganic decomposition, respiration and chemical transformations. Respiratory activities in decomposing speckled alder and trembling aspen leaves were more important than that in sweet gale. In spite of low nutrient concentrations in the water, nitrogen concentration increased in the three species while phosphorus levels increased only in the speckled alder during decomposition.
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    Benthic phosphorus regeneration in the Potomac River Estuary (1982)
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    Hydrobiologia 91-92 (1982), S. 431-446 
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    ISSN: 1573-5117
    Keywords: phosphorus ; regeneration ; fluxes ; estuarine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment.In situ benthic fluxes (0.1 to 2.0 mmoles m−2 day−1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles m−2 day−1). The discrepancy between the two flux estimates is greatest in the transition zone (river mile 50 to 70) and is attributd to macrofaunal irrigation. Bothin situ and diffusive fluxes of dissolved reactive phosphate from Potomac tidal river sediments are low while those from anoxic lower estuarine sediments are high. The net accumulation rate of phosphorus in benthic sediment exhibits an inverse pattern. Thus a large fraction of phosphorus is retained by Potomac tidal river sediments, which contain a surficial oxidized layer and oligochaete worms tolerant of low oxygen conditions, and a large fraction of phosphorus is released from anoxic lower estuary sediments. Tidal river sediment pore waters are in equilibrium with amorphous Fe (OH)3 while lower estuary pore waters are significantly undersaturated with respect to this phase. Benthic regeneration of dissolved reactive phosphorus is sufficient to supply all the phosphorus requirements for net primary production in the lower tidal river and transition-zone waters of the Potomac River Estuary. Benthic regeneration supplies approximately 25% as much phosphorus as inputs from sewage treatment plants and 10% of all phosphorus inputs to the tidal Potomac River. When all available point source phosphorus data are put into a steady-state conservation of mass model and reasonable coefficients for uptake of dissolved phosphorus, remineralization of particulate phosphorus, and sedimentation of particulate phosphorus are used in the model, a reasonably accurate simulation of dissolved and particulate phosphorus in the water column is obtained for the summer of 1980.
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    Acidified lakes: sediment treatment with sodium carbonate — a remedy? (1982)
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    Hydrobiologia 91-92 (1982), S. 537-547 
    Details
    ISSN: 1573-5117
    Keywords: lake acidification ; neutralization ; buffer capacity ; liming ; cation exchange ; humic sediment ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Until now, additions of lime have been used to restore the buffering capacity of acidified lakes, but an alternative method which is more effective in the treatment of lakes with organogenic sediments has recently been applied in a full-scale experiment. The method, called CONTRACID, is based on the cation exchange properties of lake sediment. A sodium carbonate (soda ash) solution is injected into the sediment (by a harrow), so that the sediment becomes sodium stocked. A reverse exchange occurs during subsequent acidification. Liming has a limited effect on humic lakes, since Ca-humates have a reduced reverse exchange ability and also the lime, which remains undissolved, is rendered inactive. Ionic exchange processes and nutrient transport were studied in water/sediment cores andin situ enclosures after additions of soda ash-, lye- and lime solutions with subsequent re-acidification. Sodium carbonate additions in laboratory systems resulted in a sorption to the sediment of 42–62% of the added sodium ions (5 eq m−2) and a release of 14–78 mg Pm−2 sediment. Similar results were obtained in the enclosures where phosphorus release stimulated algal growth. Sediment pH, elevated by the sodium base addition, was lowered by re-acidification. Limed systems released no phosphorus and only about 25% of the added lime remained active for future neutralization. With the injection of the sodium carbonate solution into the sediment, only about 12% of the added sodium was recovered in lake water by spring circulation. Lake water alkalinity was then 0.12 meq l−1 and pH 6.7. Total phosphorus had been raised by 0.007 mg P l−1 causing an increase in phytoplankton biomass. Observations indicate that manipulations of acidic lake sediment according to the CONTRACID method create a long-lasting neutralizing capacity and a biological stimulation (through phosphorus release), which makes the method an attractive alternative to frequent liming.
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    Carbon, phosphorus and nitrogen budgets of the littoral Equisetum belt in an oligotrophic lake (1982)
    Springer
    Hydrobiologia 86 (1982), S. 41-53 
    Details
    ISSN: 1573-5117
    Keywords: oligotrophic lakes ; Equisetum ; carbon ; phosphorus ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stores and flows of carbon, phosphorus and nitrogen in a littoral Equisetum stand were studied in 1978–1980 in the oligotrophic, mesohumic lake Pääjärvi, southern Finland. The major carbon and nutrient stores were sediment and Equisetum. The seasonal cycle of the macrophyte vegetation had a profound influence on the whole littoral ecosystem. In spring, when only dead remains of Equisetum were present above ground, there were few differences in nutrient, chlorophyll a and zooplankton concentrations between the littoral and the open lake; phytoplankton and epiphytes were the major producers. In early June, when new shoots of Equisetum reached the water surface, water exchange between the littoral and the open lake started to diminish, and the characteristic features of a closed macrophyte zone gradually developed: by August the P, Chl a and zooplankton concentrations in the littoral were 5–10 times those in the open lake. From late June until autumn Equisetum was overwhelmingly dominant both in biomass and in production. The measured total primary production and respiration values indicated a high rate of internal cycling of carbon and nutrients. The daily P requirements of plant growth exceeded the total P stored in the water by a factor of 2–4, and also exceeded the release of nutrients in excretion. High N:P ratios in the water (total 10–64, inorganic 18–171) suggested that P was probably always the limiting nutrient. The P content of the annual production of Equisetum in Pääjärvi was 2.3% of the mean annual P load, and 5.3% of the mean total P storage in the water volume of the lake.
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    Temperature dependence of sediment-water exchange in Lake Grevelingen, SW Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 489-490 
    Details
    ISSN: 1573-5117
    Keywords: laboratory experiments ; sediment types ; phosphorus ; silicon ; sediment-water exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Extended abstract Lake Grevelingen is a brackish water lake in the SW Netherlands. The lake has an area of 108 km2, a mean depth of 5.3 m (maximum 48 m), a mean chlorinity of 13 to 16%0 Cl−, and a hydraulic residence time of about 8 years. Mass budget studies have shown a consistent seasonal pattern in the phosphorus sediment-water exchange in Lake Grevelingen (Kelderman 1980). From May to August a P mobilization from the sediment takes place, estimated atca. 12.5 mg P · m−2 · day−1. The sediment accumulatesca. 5.5 mg P · m−2 · day−1 during the rest of the year. Temperature may be an important factor in establishing this pattern. Sediment-water exchange was studied by means of laboratory experiments under specified conditions. Sediment cores (30 cm depth, 11 cm diameter) were taken at four stations in the lake, with sediment types varying from medium- to muddy sand (Fig. 1). The cores with overlying water (ca. 21) were placed in the dark at 5 °C in thermostatically controlled water baths. After a week's incubation time the temperature was slowly raised, such that after three weeks eight cores (four sediment types, duplicates) were at 5 °C, eight were at 10 °C, eight at 15 °C and eight at 20 °C. The same procedure was applied to the four control cores, containing lake water.
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    Acidified lakes: sediment treatment with sodium carbonate — a remedy? (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 537-547 
    Details
    ISSN: 1573-5117
    Keywords: lake acidification ; neutralization ; buffer capacity ; liming ; cation exchange ; humic sediment ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Until now, additions of lime have been used to restore the buffering capacity of acidified lakes, but an alternative method which is more effective in the treatment of lakes with organogenic sediments has recently been applied in a full-scale experiment. The method, called CONTRACID, is based on the cation exchange properties of lake sediment. A sodium carbonate (soda ash) solution is injected into the sediment (by a harrow), so that the sediment becomes sodium stocked. A reverse exchange occurs during subsequent acidification. Liming has a limited effect on humic lakes, since Ca-humates have a reduced reverse exchange ability and also the lime, which remains undissolved, is rendered inactive. Ionic exchange processes and nutrient transport were studied in water/sediment cores andin situ enclosures after additions of soda ash-, lye- and lime solutions with subsequent re-acidification. Sodium carbonate additions in laboratory systems resulted in a sorption to the sediment of 42–62% of the added sodium ions (5 eq m−2) and a release of 14–78 mg Pm−2 sediment. Similar results were obtained in the enclosures where phosphorus release stimulated algal growth. Sediment pH, elevated by the sodium base addition, was lowered by re-acidification. Limed systems released no phosphorus and only about 25% of the added lime remained active for future neutralization. With the injection of the sodium carbonate solution into the sediment, only about 12% of the added sodium was recovered in lake water by spring circulation. Lake water alkalinity was then 0.12 meq l−1 and pH 6.7. Total phosphorus had been raised by 0.007 mg P l−1 causing an increase in phytoplankton biomass. Observations indicate that manipulations of acidic lake sediment according to the CONTRACID method create a long-lasting neutralizing capacity and a biological stimulation (through phosphorus release), which makes the method an attractive alternative to frequent liming.
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    URL: http://dx.doi.org/10.1007/BF00940142
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    Microbial metabolism in surface sediments and its role in the immobilization of phosphorus in oligotrophic lake sediments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 261-268 
    Details
    ISSN: 1573-5117
    Keywords: microbial metabolism ; phosphorus ; sediments ; oligotrophic lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rapid microbial metabolism and a large phosphorus uptake potential were observed in surface sediments of Lake George, New York. This sediment (termed the flocculent layer) also exhibited a phosphorus limited condition and a large reservoir of inorganic phosphorus associated with humic substances. These observations suggest that the empirically observed phosphorus retention in oligotrophic lake sediments may be promoted by a rapid cycling of phosphorus between microflora and its associated organic matter.
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    The phosphorus-chlorophyll a relationship in periphytic communities in a controlled ecosystem (1982)
    Springer
    Hydrobiologia 94 (1982), S. 173-176 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; chlorophyll a ; microcosm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The correlation between total dissolved phosphorus input concentrations and periphytic chlorophyll a concentrations was examined after a four-week colonization period on artificial substrates in large, continuous-flow microcosms. A significant correlation was established; the data produced a linear regression and substantiated a recently proposed curvilinear regression analysis. The curvilinear equation can be used in future microcosm studies as a predictive aid for regulating phosphorus input concentrations.
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    URL: http://dx.doi.org/10.1007/BF00010897
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    Algal-availability of particulate phosphorus from diffuse and point sources in the lower Great Lakes basin (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 111-119 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; bioavailability ; point source ; diffuse source ; Great Lakes ; bioassay ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Control of phytoplankton production in the Great Lakes can be achieved most efficiently by limiting inputs of biologically available P. We report the results of studies performed to characterize the chemical forms and availability of particulate P in wastewater and tributaries which enter the lower Lakes, the eroding bluffs which border Lake Erie, and bottom samples from the near-shore of western Lake Erie. Rates of release of available P were estimated from a simple first-order model of the process, as observed during algal bioassays. Available P in wastewater samples, as a fraction of total particulate P, was affected minimally by wastewater treatment, including chemical precipitation and filtration; it correlated well with levels of total particulate P. Available particulate P levels in fluvial suspended sediments showed regional uniformity, but appeared to be strongly dependent on levels of both NaOH-P and CDB-P. Rates of release of available P decreased during wastewater treatment to values which were similar in magnitude to those observed for fluvial sediments. Release rates, however, were not related to any of the particulate P fractions which were measured. Analysis of the bluff and bottom samples indicated that P availability in the former was negligible, but the latter contained levels which approached those of wastewater particulates, though available P was released from the bottom sediments at relatively low rates.
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    An analysis of total phosphorus transport in river systems (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 241-252 
    Details
    ISSN: 1573-5117
    Keywords: pollution ; rivers ; transport ; calculation ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Human activities generate many pollutants from different land uses. These pollutants include nutrients (e.g., phosphorus and nitrogen), toxic substances (e.g., heavy metals and pesticides), and other substances (e.g., chlorides and salts). These materials often enter a river at some upstream point and are transported downstream by the flowing water. Many substances are transported both during storms and during normal river flow and often the major portion of the transport occurs during the storms. This paper considers the quantification of transport primarily during storms. First, the characteristics of storm transport are discussed. Then, a calculation method for estimating the distance of travel for sediment related materials is presented. Third, a technique to estimate the amount of a given chemical passing a point in a stream over a specified period of time is presented. The last part of this paper contains a technique for tracing the movement of substances through a river network. In particular, this procedure yields information as to the source of given pollutants over the entire Storm period.
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    Kinetics of nitrogen and phosphorus release in varying food supplies byDaphnia magna (1982)
    Springer
    Hydrobiologia 96 (1982), S. 105-111 
    Details
    ISSN: 1573-5117
    Keywords: nitrogen ; phosphorus ; exrretion ; food quality ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of nitrogen and phosphorus release from individualDaphnia magna were determined by measuring ammonia and soluble reactive phosphorus in successive 10-min incubations in small (0.05 ml) vessels after the animals were removed from their food. Release rates of both nutrients were generally highest initially and decreased with time after removal. The ratio of nitrogen to phosphorus released increased with time after animals were removed from an artificial detritus/bacterial food; ratios were lower and changed with time less for animals fed algae. These data suggest errors may be introduced by assumptions of constant stoichiometry for nutrient release in varying environments.
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    URL: http://dx.doi.org/10.1007/BF02185425
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    Nutrient dependence of phytoplankton production in brown-water lakes with special reference to Lake Päijänne (1982)
    Springer
    Hydrobiologia 86 (1982), S. 129-132 
    Details
    ISSN: 1573-5117
    Keywords: aquatic models ; phytoplankton primary production ; chlorophyll a ; phosphorus ; humic water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method for predicting the mean seasonal chlorophyll a concentration, the mean seasonal in vitro phytoplankton primary productivity per unit volume, the maximum daily production per unit volume and the seasonal integral production in brown-water lakes is presented. The production values can be calculated when the mean annual concentration of total phosphorus and the mean annual colour of the water are known. This method has been developed especially for practical water pollution studies to permit rapid and inexpensive estimates of major biological consequences of changes in effluent loads. The method can be applied for brown-water lakes where phosphorus is the limiting nutrient for primary production.
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    Temperature dependence of sediment-water exchange in Lake Grevelingen, SW Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 489-490 
    Details
    ISSN: 1573-5117
    Keywords: laboratory experiments ; sediment types ; phosphorus ; silicon ; sediment-water exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Extended abstract Lake Grevelingen is a brackish water lake in the SW Netherlands. The lake has an area of 108 km2, a mean depth of 5.3 m (maximum 48 m), a mean chlorinity of 13 to 16%0 Cl−, and a hydraulic residence time of about 8 years. Mass budget studies have shown a consistent seasonal pattern in the phosphorus sediment-water exchange in Lake Grevelingen (Kelderman 1980). From May to August a P mobilization from the sediment takes place, estimated at ca. 12.5 mg P · m−2 · day−1. The sediment accumulates ca. 5.5 mg P · m−2 · day−1 during the rest of the year. Temperature may be an important factor in establishing this pattern. Sediment-water exchange was studied by means of laboratory experiments under specified conditions. Sediment cores (30 cm depth, 11 cm diameter) were taken at four stations in the lake, with sediment types varying from medium- to muddy sand (Fig. 1). The cores with overlying water (ca. 21) were placed in the dark at 5 °C in thermostatically controlled water baths. After a week's incubation time the temperature was slowly raised, such that after three weeks eight cores (four sediment types, duplicates) were at 5 °C, eight were at 10 °C, eight at 15 °C and eight at 20 °C. The same procedure was applied to the four control cores, containing lake water.
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    Sedimentation rates in a Swiss-Italian lake measured with sediment traps (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 603-610 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton ; tripton ; phosphorus ; mineralization ; regeneration and diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tripton sedimentation was investigated in the eutrophic Lake Lugano (Ponte Tresa basin) from October 1979 to October 1980. The annual amount of tripton collected was 748 g · m−2 · y−1. Phosphorus, nitrogen and organic carbon fluxes into the hypolimnion were estimated to be 1.9, 16.2 and 121 g · m−2y−1 respectively. Mineralization rates into the trophogenic layer varied from 11% to 19% per day during summer stratification. The regeneration processes contribute about 60% of the calculated P deficit in the epilimnion. The tripton is decomposed mostly in the metalimnion, out of the euphotic zone; from here the phosphorus is carried back to the overlying waters by diffusion processes.
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    Benthic phosphorus regeneration in the Potomac River Estuary (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 431-446 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; regeneration ; fluxes ; estuarine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment.In situ benthic fluxes (0.1 to 2.0 mmoles m−2 day−1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles m−2 day−1). The discrepancy between the two flux estimates is greatest in the transition zone (river mile 50 to 70) and is attributd to macrofaunal irrigation. Bothin situ and diffusive fluxes of dissolved reactive phosphate from Potomac tidal river sediments are low while those from anoxic lower estuarine sediments are high. The net accumulation rate of phosphorus in benthic sediment exhibits an inverse pattern. Thus a large fraction of phosphorus is retained by Potomac tidal river sediments, which contain a surficial oxidized layer and oligochaete worms tolerant of low oxygen conditions, and a large fraction of phosphorus is released from anoxic lower estuary sediments. Tidal river sediment pore waters are in equilibrium with amorphous Fe (OH)3 while lower estuary pore waters are significantly undersaturated with respect to this phase. Benthic regeneration of dissolved reactive phosphorus is sufficient to supply all the phosphorus requirements for net primary production in the lower tidal river and transition-zone waters of the Potomac River Estuary. Benthic regeneration supplies approximately 25% as much phosphorus as inputs from sewage treatment plants and 10% of all phosphorus inputs to the tidal Potomac River. When all available point source phosphorus data are put into a steady-state conservation of mass model and reasonable coefficients for uptake of dissolved phosphorus, remineralization of particulate phosphorus, and sedimentation of particulate phosphorus are used in the model, a reasonably accurate simulation of dissolved and particulate phosphorus in the water column is obtained for the summer of 1980.
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    URL: http://dx.doi.org/10.1007/BF00940132
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    Modelling the influence of bioturbation on the vertical distribution of sedimentary phosphorus in L. Esrom (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 197-206 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; modelling ; sediment ; phosphorus ; Chironomus anthracinus ; Potamothrix hammoniensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A multilayer sediment-water exchange model was used to evaluate the importance of bioturbation in the profundal sediments of L. Esrom. The temporal variation of the vertical distribution of sedimentary phosphorus fractions was modelled with an objective function of 1.50. Deviations between measured and simulated values occurred in the spring, where the measured pool of sedimentary phosphorus sharply declined in the surface sediments. The application of a model for the activity ofChironomus anthracinus based on biomass, oxygen consumption and temperature improved the model in the spring period. The downwards transport of easy-degradable surface sediments reduced the average release of sedimentary phosphorus from 12 mg P · m−2 · day−1 to 11 mg P · M−2 · day−1. The introduction of a similar model for the other important burrowing species in L. Esrom,Potamothrix hammoniensis, lowered the objective function to 1.37 and increased the average release to 12.5 mg P · m−2 · day−1. The minor role of bioturbation in sediment processes is discussed.
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    An analysis of total phosphorus transport in river systems (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 241-252 
    Details
    ISSN: 1573-5117
    Keywords: pollution ; rivers ; transport ; calculation ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Human activities generate many pollutants from different land uses. These pollutants include nutrients (e.g., phosphorus and nitrogen), toxic substances (e.g., heavy metals and pesticides), and other substances (e.g., chlorides and salts). These materials often enter a river at some upstream point and are transported downstream by the flowing water. Many substances are transported both during storms and during normal river flow and often the major portion of the transport occurs during the storms. This paper considers the quantification of transport primarily during storms. First, the characteristics of storm transport are discussed. Then, a calculation method for estimating the distance of travel for sediment related materials is presented. Third, a technique to estimate the amount of a given chemical passing a point in a stream over a specified period of time is presented. The last part of this paper contains a technique for tracing the movement of substances through a river network. In particular, this procedure yields information as to the source of given pollutants over the entire Storm period.
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    Lake Trehörningen restoration project. Changes in water quality after sediment dredging (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 549-558 
    Details
    ISSN: 1573-5117
    Keywords: lake restoration ; sediment dredging ; nitrogen ; phosphorus ; algal assays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An increased load of domestic wastewater to Lake Trehörningen induced oxygen-poor water conditions and the development of a reduced sulphide-rich sediment layer. Severely polluted, the lake did not recover, even after advanced wastewater treatment and sewage diversion. Restoration measures with suction dredging and macrophyte elimination were applied in 1975 and 1976. The loose topmost sediment was pumped into an embanked and overgrown bay which was used as a settling pond. The activities also included a restoration of the shorelines. This project is the largest restoration programme carried out in Sweden on a single lake, corresponding to a cost of about US $2 000 000. The restoration of Lake Trehörningen was followed by a highly intensive research programme which included water chemistry and algal assays. The concentrations of phosphate and total phosphorus decreased by 73 and 50% respectively, as summer average values, two years after the restoration. However, the concentrations of phosphorus are still too high to permit this element to act as a prime algal growth-limiting nutrient. The algal biomass has also remained at the same magnitude as before the restoration. Nitrate-N concentrations showed a tenfold increase, based on average values for the summer period. However, based on the results of the algal assays, a rapid and marked response was obvious, with a drastic decline in the algal growth potential. In addition, the water quality of the tributaries was frequently of an objectionable character (0.1–0.2 g P m−3). The nutrient loading from these sources exceeds the critical level for the lake, and measures have now been carried out to treat all the inflowing waters for the removal of phosphorus.
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    The fractionation of iron-phosphorus compounds in sediments studied by Mössbauer spectroscopy (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 697-700 
    Details
    ISSN: 1573-5117
    Keywords: sediments ; Mössbauer spectroscopy ; iron ; phosphorus ; geochemistry ; analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron compounds of phosphorus form a large part of the phosphorus bound in sediments. Mössbauer spectroscopy is a technique that enables us to study, directly, chemical forms of iron in solid samples. Mössbauer spectroscopy allowed us to check, directly, the selectivity of the extraction scheme for soil phosphorus proposed by Chang & Jackson (1957), but only as far as the iron compounds are concerned. It appears that selectivity of the extraction method leaves much to be desired.
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    URL: http://dx.doi.org/10.1007/BF00940159
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    Microbial metabolism in surface sediments and its role in the immobilization of phosphorus in oligotrophic lake sediments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 261-268 
    Details
    ISSN: 1573-5117
    Keywords: microbial metabolism ; phosphorus ; sediments ; oligotrophic lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rapid microbial metabolism and a large phosphorus uptake potential were observed in surface sediments of Lake George, New York. This sediment (termed the flocculent layer) also exhibited a phosphorus limited condition and a large reservoir of inorganic phosphorus associated with humic substances. These observations suggest that the empirically observed phosphorus retention in oligotrophic lake sediments may be promoted by a rapid cycling of phosphorus between microflora and its associated organic matter.
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    URL: http://dx.doi.org/10.1007/BF00940117
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    Temperature dependence of sediment-water exchange in Lake Grevelingen, SW Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 489-490 
    Details
    ISSN: 1573-5117
    Keywords: laboratory experiments ; sediment types ; phosphorus ; silicon ; sediment-water exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Extended abstract Lake Grevelingen is a brackish water lake in the SW Netherlands. The lake has an area of 108 km2, a mean depth of 5.3 m (maximum 48 m), a mean chlorinity of 13 to 16%0 Cl−, and a hydraulic residence time of about 8 years. Mass budget studies have shown a consistent seasonal pattern in the phosphorus sediment-water exchange in Lake Grevelingen (Kelderman 1980). From May to August a P mobilization from the sediment takes place, estimated atca. 12.5 mg P · m−2 · day−1. The sediment accumulatesca. 5.5 mg P · m−2 · day−1 during the rest of the year. Temperature may be an important factor in establishing this pattern. Sediment-water exchange was studied by means of laboratory experiments under specified conditions. Sediment cores (30 cm depth, 11 cm diameter) were taken at four stations in the lake, with sediment types varying from medium- to muddy sand (Fig. 1). The cores with overlying water (ca. 21) were placed in the dark at 5 °C in thermostatically controlled water baths. After a week's incubation time the temperature was slowly raised, such that after three weeks eight cores (four sediment types, duplicates) were at 5 °C, eight were at 10 °C, eight at 15 °C and eight at 20 °C. The same procedure was applied to the four control cores, containing lake water.
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    Epilimnetic nutrient loading by metalimnetic erosion and resultant algal responses in Lake Waramaug, Connecticut (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 501-510 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; nutrient cycling ; stratification ; epilimnion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphorus regeneration from lake sediments, and subsequent migration to trophogenic surface water, significantly contributes to the lake nutrient budgets and algal bloom conditions in some lake types. Decomposition of organic matter in deep water and sediments results in the accumulation of regenerated nutrients, alternate electron acceptors (reduced products of anaerobic respiration = COD), carbon dioxide, and depletion of dissolved oxygen (electron acceptor in aerobic respiration). Thermal stratification creates spatial segregation of trophogenic and tropholytic environments in the lake, resulting in gradients between sediments, hypolimnion, and the epilimnion. Exchange of oxygen, nutrients, and reduced alternate electron acceptors between the hypolimnion and epilimnion affects the productivity of a lake. Secchi depth, temperature, and dissolved oxygen profiles were determined twice each week from May 1980 to October 1980 at each of five lake stations. Nutrient concentration profiles, including total soluble and total phosphorus, ammonium-N, nitrate, soluble Kjeldahl, and total Kjeldahl nitrogen were determined twice each month. Epilimnetic algal samples were collected twice each week using Kemmerer and water column ‘straw’ amplers. Cell counts of total, green, bluegreen, and diatom algae groups were made. Three methods were used to describe hypolimnetic-epilimnetic exchange, including coefficients of eddy diffusion (based on lake heat budget), a graphical method of defining thermocline location, and relative thermal resistance to mixing (RTRM, based on density differences). All three methods yeilded comparable estimates of net seasonal transport. The graphical and RTRM methods described events occurring at shorter intervals (greater resolution). We find general agreement between the three methods of describing hypolimnetic-epilimnetic transport. The frequency of sampling resulted in increased resolution of thermal profiles (in time), allowing accurate estimation of short-term nutrient flux into epilimnetic waters. An algal bloom event occurred 5 to 12 days following erosion of the top of the metalimnion to below the aerobic-anaerobic interface. The lag time to peak algal concentration, following such events, decreased through the summer (June = 12 days, September = 5 days)
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    The fractionation of iron-phosphorus compounds in sediments studied by Mössbauer spectroscopy (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 697-700 
    Details
    ISSN: 1573-5117
    Keywords: sediments ; Mössbauer spectroscopy ; iron ; phosphorus ; geochemistry ; analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron compounds of phosphorus form a large part of the phosphorus bound in sediments. Mössbauer spectroscopy is a technique that enables us to study, directly, chemical forms of iron in solid samples. Mössbauer spectroscopy allowed us to check, directly, the selectivity of the extraction scheme for soil phosphorus proposed by Chang & Jackson (1957), but only as far as the iron compounds are concerned. It appears that selectivity of the extraction method leaves much to be desired.
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    Modelling the influence of bioturbation on the vertical distribution of sedimentary phosphorus in L. Esrom (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 197-206 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; modelling ; sediment ; phosphorus ; Chironomus anthracinus ; Potamothrix hammoniensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A multilayer sediment-water exchange model was used to evaluate the importance of bioturbation in the profundal sediments of L. Esrom. The temporal variation of the vertical distribution of sedimentary phosphorus fractions was modelled with an objective function of 1.50. Deviations between measured and simulated values occurred in the spring, where the measured pool of sedimentary phosphorus sharply declined in the surface sediments. The application of a model for the activity ofChironomus anthracinus based on biomass, oxygen consumption and temperature improved the model in the spring period. The downwards transport of easy-degradable surface sediments reduced the average release of sedimentary phosphorus from 12 mg P · m−2 · day−1 to 11 mg P · M−2 · day−1. The introduction of a similar model for the other important burrowing species in L. Esrom,Potamothrix hammoniensis, lowered the objective function to 1.37 and increased the average release to 12.5 mg P · m−2 · day−1. The minor role of bioturbation in sediment processes is discussed.
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    URL: http://dx.doi.org/10.1007/BF02391936
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    Excretion of total phosphorus, dissolved reactive phosphorus, ammonia, and urea by Lake MichiganMysis relicta (1982)
    Springer
    Hydrobiologia 93 (1982), S. 145-154 
    Details
    ISSN: 1573-5117
    Keywords: Mysidacea ; Mysis relicta ; Lake Michigan ; phosphorus ; nitrogen ; nutrient cycling ; urea ; ammonia ; vertical migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of nutrient release byMysis relicta in Lake Michigan were measured on five nights at a 45-m station near Milwaukee, Wisconsin, U.S.A., in the summer of 1977. Nocturnal vertical migrations of the mysids were monitored with both echosounder tracings and vertical net tows. Estimates of the total areal dry mass of the mysids ranged from 600 to 1 820 mg m−2. Rates of release of dissolved reactive phosphorus, total phosphorus, ammonia, and urea were measured in dark incubations on shipboard. Excretion experiments were initiated immediately after mysids were collected from each of several vertical net hauls. The depths of maximum mysid densities corresponded approximately with a deep phytoplankton peak located in the vicinity of the thermocline. Semiquantitative ‘demands’ for N and P by phytoplankton within this peak were obtained from14C estimates of primary production from a previous study, assuming a constant C:N:P ratio for the algae. These algal nutrient ‘demands’ were compared to potential N and P release by the mysids to obtain a first approximation of the relative rates of nutrient supply and demand for the field phytoplankton populations. Our analysis indicates that mysids may directly supply about 1–10% of the daily N and P ‘demands’ of the phytoplankton in the deep peak. However, indirect interactions betweenMysis relicta and other organisms, such as small zooplankton and fishes, could be major factors in nutrient recycling within the metalimnion and subthermocline region of Lake Michigan.
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    URL: http://dx.doi.org/10.1007/BF00008107
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    The phosphorus economy of a hypertrophic seepage lake in Scania, south Sweden groundwater influence (1982)
    Springer
    Hydrobiologia 86 (1982), S. 153-158 
    Details
    ISSN: 1573-5117
    Keywords: lake water ; phosphorus ; sedimenting material ; groundwater ; water and nutrient budget ; hypertrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus dynamics and economy of Lake Bysjön, a hypertrophic seepage lake in Scania, southern Sweden, were investigated during 1973–1977. The mean dissolved inorganic phosphorus concentration (1973–1977) was 580 µg · l−1. There were no correlations between dissolved inorganic P, total organic P, dissolved organic P, particulate P and phytoplankton biomass. Groundwater inflow and lake water outflow through the ground are the most important factors for maintaining a constant water volume. Groundwater seepage is also important for water quality. Groundwater inflow, together with planktonic activity, keeps the P concentration high in the lake water.
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    URL: http://dx.doi.org/10.1007/BF00005803
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    The fractionation of iron-phosphorus compounds in sediments studied by Mössbauer spectroscopy (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 697-700 
    Details
    ISSN: 1573-5117
    Keywords: sediments ; Mössbauer spectroscopy ; iron ; phosphorus ; geochemistry ; analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron compounds of phosphorus form a large part of the phosphorus bound in sediments. Mössbauer spectroscopy is a technique that enables us to study, directly, chemical forms of iron in solid samples. Mössbauer spectroscopy allowed us to check, directly, the selectivity of the extraction scheme for soil phosphorus proposed by Chang & Jackson (1957), but only as far as the iron compounds are concerned. It appears that selectivity of the extraction method leaves much to be desired.
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    URL: http://dx.doi.org/10.1007/BF00000069
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    Algal-availability of particulate phosphorus from diffuse and point sources in the lower Great Lakes basin (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 111-119 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; bioavailability ; point source ; diffuse source ; Great Lakes ; bioassay ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Control of phytoplankton production in the Great Lakes can be achieved most efficiently by limiting inputs of biologically available P. We report the results of studies performed to characterize the chemical forms and availability of particulate P in wastewater and tributaries which enter the lower Lakes, the eroding bluffs which border Lake Erie, and bottom samples from the near-shore of western Lake Erie. Rates of release of available P were estimated from a simple first-order model of the process, as observed during algal bioassays. Available P in wastewater samples, as a fraction of total particulate P, was affected minimally by wastewater treatment, including chemical precipitation and filtration; it correlated well with levels of total particulate P. Available particulate P levels in fluvial suspended sediments showed regional uniformity, but appeared to be strongly dependent on levels of both NaOH-P and CDB-P. Rates of release of available P decreased during wastewater treatment to values which were similar in magnitude to those observed for fluvial sediments. Release rates, however, were not related to any of the particulate P fractions which were measured. Analysis of the bluff and bottom samples indicated that P availability in the former was negligible, but the latter contained levels which approached those of wastewater particulates, though available P was released from the bottom sediments at relatively low rates.
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    URL: http://dx.doi.org/10.1007/BF00940100
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    Benthic phosphorus regeneration in the Potomac River Estuary (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 431-446 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; regeneration ; fluxes ; estuarine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment. In situ benthic fluxes (0.1 to 2.0 mmoles m−2 day−1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles m−2 day−1). The discrepancy between the two flux estimates is greatest in the transition zone (river mile 50 to 70) and is attributd to macrofaunal irrigation. Both in situ and diffusive fluxes of dissolved reactive phosphate from Potomac tidal river sediments are low while those from anoxic lower estuarine sediments are high. The net accumulation rate of phosphorus in benthic sediment exhibits an inverse pattern. Thus a large fraction of phosphorus is retained by Potomac tidal river sediments, which contain a surficial oxidized layer and oligochaete worms tolerant of low oxygen conditions, and a large fraction of phosphorus is released from anoxic lower estuary sediments. Tidal river sediment pore waters are in equilibrium with amorphous Fe (OH)3 while lower estuary pore waters are significantly undersaturated with respect to this phase. Benthic regeneration of dissolved reactive phosphorus is sufficient to supply all the phosphorus requirements for net primary production in the lower tidal river and transition-zone waters of the Potomac River Estuary. Benthic regeneration supplies approximately 25% as much phosphorus as inputs from sewage treatment plants and 10% of all phosphorus inputs to the tidal Potomac River. When all available point source phosphorus data are put into a steady-state conservation of mass model and reasonable coefficients for uptake of dissolved phosphorus, remineralization of particulate phosphorus, and sedimentation of particulate phosphorus are used in the model, a reasonably accurate simulation of dissolved and particulate phosphorus in the water column is obtained for the summer of 1980.
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    URL: http://dx.doi.org/10.1007/BF00000042
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    Epilimnetic nutrient loading by metalimnetic erosion and resultant algal responses in Lake Waramaug, Connecticut (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 501-510 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus ; nutrient cycling ; stratification ; epilimnion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phosphorus regeneration from lake sediments, and subsequent migration to trophogenic surface water, significantly contributes to the lake nutrient budgets and algal bloom conditions in some lake types. Decomposition of organic matter in deep water and sediments results in the accumulation of regenerated nutrients, alternate electron acceptors (reduced products of anaerobic respiration = COD), carbon dioxide, and depletion of dissolved oxygen (electron acceptor in aerobic respiration). Thermal stratification creates spatial segregation of trophogenic and tropholytic environments in the lake, resulting in gradients between sediments, hypolimnion, and the epilimnion. Exchange of oxygen, nutrients, and reduced alternate electron acceptors between the hypolimnion and epilimnion affects the productivity of a lake. Secchi depth, temperature, and dissolved oxygen profiles were determined twice each week from May 1980 to October 1980 at each of five lake stations. Nutrient concentration profiles, including total soluble and total phosphorus, ammonium-N, nitrate, soluble Kjeldahl, and total Kjeldahl nitrogen were determined twice each month. Epilimnetic algal samples were collected twice each week using Kemmerer and water column ‘straw’ amplers. Cell counts of total, green, bluegreen, and diatom algae groups were made. Three methods were used to describe hypolimnetic-epilimnetic exchange, including coefficients of eddy diffusion (based on lake heat budget), a graphical method of defining thermocline location, and relative thermal resistance to mixing (RTRM, based on density differences). All three methods yeilded comparable estimates of net seasonal transport. The graphical and RTRM methods described events occurring at shorter intervals (greater resolution). We find general agreement between the three methods of describing hypolimnetic-epilimnetic transport. The frequency of sampling resulted in increased resolution of thermal profiles (in time), allowing accurate estimation of short-term nutrient flux into epilimnetic waters. An algal bloom event occurred 5 to 12 days following erosion of the top of the metalimnion to below the aerobic-anaerobic interface. The lag time to peak algal concentration, following such events, decreased through the summer (June = 12 days, September = 5 days)
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    Sedimentation rates in a Swiss-Italian lake measured with sediment traps (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 603-610 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton ; tripton ; phosphorus ; mineralization ; regeneration and diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tripton sedimentation was investigated in the eutrophic Lake Lugano (Ponte Tresa basin) from October 1979 to October 1980. The annual amount of tripton collected was 748 g · m−2 · y−1. Phosphorus, nitrogen and organic carbon fluxes into the hypolimnion were estimated to be 1.9, 16.2 and 121 g · m−2y−1 respectively. Mineralization rates into the trophogenic layer varied from 11% to 19% per day during summer stratification. The regeneration processes contribute about 60% of the calculated P deficit in the epilimnion. The tripton is decomposed mostly in the metalimnion, out of the euphotic zone; from here the phosphorus is carried back to the overlying waters by diffusion processes.
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    URL: http://dx.doi.org/10.1007/BF00940149
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    Lake Trehörningen restoration project. Changes in water quality after sediment dredging (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 549-558 
    Details
    ISSN: 1573-5117
    Keywords: lake restoration ; sediment dredging ; nitrogen ; phosphorus ; algal assays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An increased load of domestic wastewater to Lake Trehörningen induced oxygen-poor water conditions and the development of a reduced sulphide-rich sediment layer. Severely polluted, the lake did not recover, even after advanced wastewater treatment and sewage diversion. Restoration measures with suction dredging and macrophyte elimination were applied in 1975 and 1976. The loose topmost sediment was pumped into an embanked and overgrown bay which was used as a settling pond. The activities also included a restoration of the shorelines. This project is the largest restoration programme carried out in Sweden on a single lake, corresponding to a cost of about US $2 000 000. The restoration of Lake Trehörningen was followed by a highly intensive research programme which included water chemistry and algal assays. The concentrations of phosphate and total phosphorus decreased by 73 and 50% respectively, as summer average values, two years after the restoration. However, the concentrations of phosphorus are still too high to permit this element to act as a prime algal growth-limiting nutrient. The algal biomass has also remained at the same magnitude as before the restoration. Nitrate-N concentrations showed a tenfold increase, based on average values for the summer period. However, based on the results of the algal assays, a rapid and marked response was obvious, with a drastic decline in the algal growth potential. In addition, the water quality of the tributaries was frequently of an objectionable character (0.1–0.2 g P m−3). The nutrient loading from these sources exceeds the critical level for the lake, and measures have now been carried out to treat all the inflowing waters for the removal of phosphorus.
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    Fine structure of the larval rhinophores of the nudibranch, Rostanga pulchra, with emphasis on the sensory receptor cells (1982)
    Springer
    Cell & tissue research 225 (1982), S. 235-248 
    Details
    ISSN: 1432-0878
    Keywords: Rhinophore ; Larva ; Nudibranch ; Sensory cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rhinophores of the veliger larva of Rostanga pulchra are located in the intravelar field near the base of the velar lobes. Each rhinophore is a cylindrical structure, tapering distally, and covered with a dense meshwork of microvilli. A conspicuous row of ciliary tufts runs along each side of the rhinophore and several stiffer tufts, composed of fewer cilia, are positioned around the tip or at the base. The rhinophoral epithelium consists of supporting cells, ciliated cells (giving rise to the ciliary rows), dendritic terminals (giving rise to the tufts around the apex), and sinuses containing occasional amebocytes. The lumen of the rhinophore is occupied by the rhinophoral ganglion and muscle cells that are oriented in two perpendicular planes. Cell bodies of the dendritic endings are located within the rhinophoral ganglion, which in turn joins into the optic and cerebral ganglia. Rhinophoral ganglionic neurons do not synapse with each other, but numerous neuromuscular synapses are found in the lumen of the rhinophore. Morphological evidence suggests that the dendritic endings are chemoreceptors and the ciliated cells are possibly mechanoreceptors but are not functional at this stage in development. The functional role of the rhinophores is discussed in relation to larval behavior at settlement and metamorphosis.
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    Ultrastructure of pinealocytes of the kangaroo rat (Dipodomys ordi) (1982)
    Springer
    Cell & tissue research 226 (1982), S. 167-175 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Ultrastructure ; Kangaroo rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the pinealocytes of the wild-captured ord kangaroo rat (Dipodomys ordi) was examined. A homogeneous population of pinealocytes was present in the pineal gland of the kangaroo rat. The Golgi apparatus, granular endoplasmic reticulum, mitochondria, lysosomes, dense-core vesicles, vacuoles containing a flocculent material and lipid droplets were consistent components of the pinealocyte cytoplasm, whereas infrequently-observed organelles included centrioles, multivesicular bodies, subsurface cisternae, “synaptic” ribbons and cilia. The number of dense-core vesicles was relatively high and dense-core vesicles and vacuoles containing a flocculent material were present in the same cell. Although it has been recently suggested that two different secretory processes, i.e., neurosecretory-like (Golgi apparatus — dense-core vesicles) and ependymal-like (granular endoplasmic reticulum — vacuoles containing a flocculent material) may be involved in different regulatory mechanisms in the pinealocytes, the definitive answer to this is still far from clear. Therefore, the pineal gland of the kangaroo rat appears to be a good model for the study of the potential relationship between these two secretory processes, especially in respect to seasonal changes.
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    The fine structure of the polymorphic spermatozoa of Fusitriton oregonensis (Mollusca: Gastropoda), with notes on the cytochemistry of the internal secretions (1982)
    Springer
    Cell & tissue research 227 (1982), S. 235-255 
    Details
    ISSN: 1432-0878
    Keywords: Sperm polymorphism ; Ultrastructure ; Mollusca ; Prosobranchia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The prosobranch Fusitriton oregonensis exhibits an unusual form of sperm polymorphism. The viable, eupyrene sperm are attached in groups of about fifty to worm-shaped, apyrene, carrier sperm. There is a second apyrene sperm, which is lancet-shaped and has a different internal organization than the carrier, but does not transport eupyrene sperm. The eupyrene sperm are filiform (185 μm long), with a conical acrosome, elongate nucleus and midpiece. They contain large stores of glycogen in the principal piece, together with an unusually high proportion of protein. The latter is due to a complex interconnecting system of fibres that supports the tail internally. A distinct annulus is located, characteristically, at the junction between midpiece and principal piece. The carrier sperm has a core of about 112 axonemes that arise from basal bodies in the anterior end and extend through its entire length of 36 μm. The basal bodies have unstriated rootlets that are embedded in a granular cap. Large membrane-bound “yolk bodies” are arranged along the length of the carrier sperm, on either side of the median axonemal core. Dense bodies, which may be indigestible residues formed from the degeneration of the nucleus, are excreted by exocytosis. Individual carrier sperm are capable of “corkscrew” propulsion, resembling that of spirochaetes. The lancet sperm is three times as long as the carrier. The sixteen or so axonemes, which are arranged peripherally like a cage enclosing the cytoplasm, originate from a dense centriolar plate in the anterior end. The cytoplasm is filled with secretions including small yolk granules, dense bodies (also excreted), clear vesicles, and a membranated granular secretion that resembles mucus. The possible functions of the lancet and carrier sperm are discussed.
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    Three-dimensional organization of smooth muscle cells in blood vessels of laboratory rodents (1982)
    Springer
    Cell & tissue research 227 (1982), S. 429-437 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Arteriole ; Three-dimension ; Ultrastructure ; Laboratory rodents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three-dimensional aspects of smooth muscle cells of the microvas-culature were studied ultrastructurally in laboratory rodents by means of serial thin sections and reconstruction of muscle cell models. It was demonstrated that a muscle cell of an arteriole (luminal diameter (LD) 17 μm) in hamster striated muscle was spindle-shaped, 70 μm long, and wound twice round the vessel axis. The volume of the cell was calculated as 750 μm3 and its surface area as 1330 μm2. A muscle cell in an arteriole (LD 6 μm) in the rat retina was irregular in shape, about 22 μm long, and had branched processes. The cell volume was calculated as 139 μm3 and its surface area as 298 μm2.
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    The interstitial cells in the colon of the rabbit (1982)
    Springer
    Cell & tissue research 222 (1982), S. 41-51 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Interstitial cell ; Myenteric plexus ; Colon ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The interstitial cells associated with the myenteric plexus of the rabbit colon were studied by scanning and transmission electron microscopy. It was demonstrated that the interstitial cells were stellate or fusiform in shape and located over the ganglia, over nerve bundles and between muscle cells. They were characterized by many slender processes, and resemble fibroblasts. No basal lamina was observed between the interstitial cells and muscle cells. It was concluded that structural features of the interstitial cells are distinctly different from those of neurons, Schwann cells, or of smooth muscle cells, while they show clear similarities to those of fibroblasts. By scanning electron microscopy the shapes and the relations of these cells could be demonstrated in great detail.
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    Noradrenergic axon terminals in the substantia gelatinosa of the rat spinal cord (1982)
    Springer
    Cell & tissue research 222 (1982), S. 359-378 
    Details
    ISSN: 1432-0878
    Keywords: Axon terminals ; Substantia gelatinosa ; Spinal cord ; Noradrenaline ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The noradrenergic terminals in the substantia gelatinosa of the dorsal horn of the cervical spinal cord of the rat were investigated by means of the histofluorescence technique and electron-microscopic cytochemistry using the glyoxylic acid-KMnO4 fixation technique. In accordance with the topographical distribution of fluorescent catecholaminergic fibers, noradrenergic terminals containing small granular vesicles were frequently observed electron microscopically in the outer layer of the substantia gelatinosa. These terminals were most frequently found to appose without showing typical synaptic features, small-caliber dendrites, spine apparatus, and rarely, large caliber dendrites. Only in a few cases, the noradrenergic terminals exhibited typical synaptic contacts with dendritic elements of small size. In addition, noradrenergic terminals apposed non-noradrenergic terminals containing small agranular vesicles. In rats bearing surgical lesions of the dorsal roots, no noradrenergic terminal were found in contact with the degenerated axon terminals in the substantia gelatinosa. These findings suggest that the noradrenergic afferents to the substantia gelatinosa may exert their influence on sensory transmission via dorsal horn cells.
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    Presence of dense-core vesicles in pinealocytes of the cat (1982)
    Springer
    Cell & tissue research 222 (1982), S. 695-698 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Ultrastructure ; Dense-core vesicles ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dense-core vesicles, 90–200 nm in diameter, were found in pinealocytes of the cat. They were present both in perikarya and cell processes.
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    URL: http://dx.doi.org/10.1007/BF00213868
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    Ultrastructural immunocytochemical characterization of isotocin, vasotocin and neurophysin neurons in the magnocellular preoptic nucleus of the goldfish (1982)
    Springer
    Cell & tissue research 223 (1982), S. 685-694 
    Details
    ISSN: 1432-0878
    Keywords: Immunoelectron microscopy ; Preoptic nucleus ; Goldfish ; Magnocellular neuroendocrine cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We describe the ultrastructural localization of isotocin, vasotocin and neurophysin in the magnocellular preoptic nucleus of the goldfish. With the aid of immunocytochemical techniques, we see staining both in classical neurosecretory granules and in diffuse agranular form throughout somata and processes. Signs of cellular and synaptic interactions between chemically identified neurons include axon terminals which contain vasotocin immunoreactivity and membrane specializations (puncta adhaerentia) between adjacent somata. Our investigations provide an anatomical basis for neuroendocrine and neurotransmitter-like functions of peptidergic neurons in the teleost preoptic nucleus.
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    URL: http://dx.doi.org/10.1007/BF00218487
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  • 92
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    The pinealocyte nucleolus (1982)
    Springer
    Cell & tissue research 224 (1982), S. 195-206 
    Details
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Nucleolus ; Rat ; Ultrastructure ; Twenty-four-hour changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and morphometric analysis was made of the nucleolar components in pinealocytes of 40 male Fischer rats sampled at eight times in an LD 12∶12 photoperiod cycle. Comparisons of results from the eight times showed variation in estimated mean volume of the granular component of ±29%, and of the fibrillar component ±11%, in relation to daily means. Peaks in mean volume of total nucleolus and its granular component occurred at 1 h of light. Near maximal and minimal mean volumes of the fibrillar component both occurred during both light and dark. Fibrillar centers (nucleolar organizer regions) of different sizes were found at all sampling times. It is concluded that temporal patterns in 24-h changes in the nucleolar components are most prominent in the granular component, and are more complex than suggested by changes in total nucleolar size or mean dimensions, and than represented by a simple biphasic circadian rhythm. Examples of different stages in the migration of the granular component, and of possible sites of nucleo-cytoplasmic transfer of nucleolar material, are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217279
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  • 93
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    Ultrastructure of gut-associated lymphoid tissue (GALT) in the amphibian urodele, Pleurodeles waltlii (1982)
    Springer
    Cell & tissue research 224 (1982), S. 663-671 
    Details
    ISSN: 1432-0878
    Keywords: GALT (gut-associated lymphoid tissue) ; Urodeles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'ultrastructure du tissu lymphoïde associé au tube digestif (GALT) a été étudiée chez l'amphibien urodèle, Pleurodeles waltlii. Les follicules lymphoïdes se présentent comme de vrais infiltrés entre les éléments conjonctifs de la muqueuse. Ils se trouvent principalement constitués par des plasmocytes mûrs et en développement, des macrophages et des granulocytes. Les cellules lymphoïdes migratrices provoquent une invasion massive de l'épithelium intestinal qui présente des modifications notables comme la disparition de la membrane basale et une diminution du nombre de cellules muqueuses. D'après son organisation et ses composants cellulaires, le GALT de P. waltlii semble représenter un précurseur phylogénétique primitif de la “barrière immunologique intestinale” des mammifères.
    Notes: Summary The ultrastructure of gut-associated lymphoid tissue (GALT) has been studied in the salamander, Pleurodeles waltlii. Lymphoid accumulations appear as true infiltrates scattered throughout the lamina propria cell elements. The most important components of these infiltrates are small and medium sized lymphocytes, and, in lesser amounts, developing and mature plasma cells, macrophages and granulocytes. Migrating lymphoid cells massively invade the intestinal epithelium inducing noticeable modifications, such as the disappearance of the basement membrane and decreased numbers of mucous cells. Thus, in its organization and cell composition, the GALT of P. waltlii appears to represent a primitive phylogenetic precursor of the mammalian “intestinalimmunologic ” barrier.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213761
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  • 94
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    Histotopography and ultrastructure of the thin limbs of the loop of Henle in the hamster (1982)
    Springer
    Cell & tissue research 225 (1982), S. 111-127 
    Details
    ISSN: 1432-0878
    Keywords: Loops of Henle ; Thin limbs ; Kidney (hamster) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the kidney of the Syrian hamster the descending thin limbs of both the short and long loops of Henle are not spatially separated from each other and descend between the vascular bundles. Ultrastructurally, five different epithelial types are distinguished in the thin limbs of the short and long loops of Henle. Short loops possess only a descending thin limb with a simply organized epithelium (type 1). Long loops comprise an upper and a lower part of the descending thin limb and the ascending thin limb. The upper part of the long descending thin limb is equipped with a complex and highly interdigitating epithelium with shallow junctions (type 2), which gradually transforms into the simple noninterdigitating type-3 epithelium of the lower part. In a minor portion of long descending thin limbs, however, the upper part begins with an even more complexly organized epithelium (type 2a) than type 2. Type-2a epithelium is conspicuously thicker and possesses a more elaborate mode of cellular interdigitation. Along the descent of this tubular part through the inner stripe of the outer medulla, type-2a epithelium transforms into type-2 epithelium. It is suggested that the long descending thin limbs, which start with type-2a epithelium, belong to the longest loops. The type-4 epithelium of the ascending thin limbs is characterized by flat and extensively interdigitating cells with shallow junctions. The unique pattern of the type-2 a epithelium favors the assumption that solute secretion essentially contributes to the increase in concentration of tubular fluid in long descending thin limbs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216222
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  • 95
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    Effects of acute opiate-peptide administration on pro-opiomelanocortin cells of the intermediate lobe of the rat pituitary (1982)
    Springer
    Cell & tissue research 225 (1982), S. 217-222 
    Details
    ISSN: 1432-0878
    Keywords: Opiate peptides ; Pituitary ; Pro-opiomelanocortin cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of acute injections of synthetic opiate peptides into the lateral cerebral ventricle of young adult male rats on cells of the intermediate lobe of the pituitary were studied. Met-enkephalin (100/μg) injected into anesthetized rats, or 20 μg beta-endorphin administered via a previously implanted cannula to unanesthetized animals, will lead to cell degranulation and often to expanded Golgi zones and prominent regions of rough endoplasmic reticulum in secretory cells when tissue is fixed 45–60 min after peptide administration. Treatment of animals with the opiate antagonist naloxone hydrochloride prior to enkephalin injection appeared to prevent the cellular changes elicited with peptide alone. Observations suggest that opiate peptides administered to the cerebrospinal fluid may stimulate release of pro-opiomelanocortin-peptide from pituitary cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216230
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  • 96
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    Development of the ovarian surface and associated germ cells in the human fetus (1982)
    Springer
    Cell & tissue research 226 (1982), S. 493-510 
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    ISSN: 1432-0878
    Keywords: Ovarian cords ; Surface epithelium ; Fetal germ cells ; Mesonephros ; Ultrastructure ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ovarian surface and associated germ cells have been studied in human fetuses from 12 weeks of age until near term, using light, TEM and SEM techniques. The surface epithelium and related cords proliferate extensively, especially at midterm. The cords in the ovarian cortex appear to be linked with ingrowths from the surface epithelium, and both structures have a common basal lamina. Germ cells are always interspersed among the somatic cells of the surface epithelium and associated cords. These results indicate that both the proliferating cords and surface epithelium may contribute to the formation of early follicles. Furthermore, the occurrence, of elements having some of the features of primitive steroidogenic cells in the regions of cordsurface epithelium continuity, suggests that both structures (surface epithelium and cords) contribute somatic cells, which in addition to becoming granulosa cells, might also contribute to the provision of primitive interstitial cells. Gonocytes tend to migrate through the developing ovarian tissue towards the surface where they become extruded into the peritoneal cavity. This phenomenon might contribute to the reduction in the number of germ cells at birth and parallels the atretic processes within the ovary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214779
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  • 97
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    A quantitative ultrastructural analysis of changes in hamster cheek-pouch epithelium treated with vitamin A (1982)
    Springer
    Cell & tissue research 226 (1982), S. 541-554 
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    ISSN: 1432-0878
    Keywords: Oral epithelium ; Cell differentiation ; Vitamin A ; Ultrastructure ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes induced by the topical application of retinol acetate on hamster cheek pouch epithelium were evaluated using stereological analysis. Electron micrographs were prepared of the basal and superficial regions of the nucleated cell layer of the epithelium obtained from 3 treated and 3 control animals and examined at two levels of magnification. A total of 528 micrographs were analyzed using a coherent double lattice test system. Although the mean thickness of the nucleated cell layer did not change significantly after 10 days of treatment with retinol acetate the formation of keratinized squames was completely inhibited. This was paralleled by significant changes in the volume density of a number of organelles in both the basal and superficial strata. Rough endoplasmic reticulum increased significantly whereas filaments, which maintained a constant diameter of approximately 9 nm, keratohyalin granules and membrane-coating granules decreased in both strata. Desmosomes also showed a significant decrease in numerical area density in the treated tissues. In contrast, no changes were observed in the volume density of the Golgi apparatus, free ribosomes or mitochondria in the treated epithelium. It is concluded that this treatment provides an epithelium lacking all features of keratinization and may be a useful model for examining metabolic activities specifically associated with keratinization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214783
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    The structure of a hair mechanoreceptor in the antennule of crayfish (Crustacea) (1982)
    Springer
    Cell & tissue research 226 (1982), S. 565-578 
    Details
    ISSN: 1432-0878
    Keywords: Mechanosensory hair ; Chordotonal organ ; Ultrastructure ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this study we examine the fine structure of mechanosensory hairs in the antennule of crayfish. The sensory hair is a stiff shaft with feather-like filaments. The hair's base is a large expansion of membrane which allows the hair shaft to deflect. The sensory transducing elements are located far from the hair, but are coupled mechanically with the hair shaft by a fine extracellular chorda. The sensory element is a type of scolopidium which consists of a scolopale cell and three sensory cells with a 9 + 0 type ciliary process. This type of scolopidium is characteristic of the chordotonal organ that has no cuticular structure on the surface of the exoskeleton. In this crustacean hair receptor, the deflection of the cuticular hair is transmitted through the chorda to the scolopidium which is a tension-sensitive transducer. The present study reveals that the mechanosensory hair of decapod crustaceans is a chordotonal organ accompanied by a cuticular hair structure. We also discuss comparative aspects of cuticular and subcuticular chordotonal organs in arthropods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214785
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  • 99
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    Correlation of mitochondrial form and function in vivo: Microinjection of substrate and nucleotides (1982)
    Springer
    Cell & tissue research 227 (1982), S. 129-137 
    Details
    ISSN: 1432-0878
    Keywords: Mitochondria ; Ultrastructure ; Microinjection ; ATP ; ADP ; Amoeba proteus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microinjection of adenine nucleotides and substrates into the cytoplasm of Amoeba proteus followed by EM examination has been used in an attempt to relate alterations in mitochondrial morphology with functional changes. Contracted mitochondria with dark matrix and wide cristae (Type I), and expanded mitochondria with light matrix and narrower cristae (Type II) coexist in normal active amoebae, but their numbers can be varied according to different cell activity states. Following injection of ATP, the mitochondria of the amoebae showed a time-dependent movement towards a predominately Type II form, whilst injections of ADP produced predominately the Type I form. Injection of succinate or deionised water, even in large amounts, had little effect on the numbers of Type I or Type II forms. The change induced by ATP was of long duration; that induced by ADP was influenced by both concentration injected and the cell's substrate levels. With 3 mM solutions of ADP the mitochondrial population was primarily of Type I organelles; higher ADP concentrations or the simultaneous injection of succinate, however, resulted in a switch with time to increased proportions of Type II mitochondria. The results extend the findings of previous in vivo and in vitro mitochondrial studies and are discussed in the light of these.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00206336
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  • 100
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    A light- and electron-microscopic study on the migration of primordial germ cells in the teleost, Oryzias latipes (1982)
    Springer
    Cell & tissue research 227 (1982), S. 139-151 
    Details
    ISSN: 1432-0878
    Keywords: Migration ; Primordial germ cell ; Teleost ; Oryzias latipes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The primordial germ cells (PGCs) of Oryzias latipes in migration to the gonadal anlage have been investigated by light and electron microscopy. The ultrastructure of the PGCs, which occur in the subendodermal space on the syncytial periblast, differ conspicuously from that of the surrounding endodermal cells. After the PGCs move to the cavity between lateral plate and ectoderm, they are taken into the somatomesodermal layer and transferred to the dorsal mesentery where they form gonadal anlage with mesodermal cells. During their translocation to the dorsal mesentery through the somatic mesoderm, apparently without formation of pseudopods, the PGCs are completely surrounded by mesodermal cells. Since these conditions seem unfavorable to the active translocation of the PGCs to the dorsal mesentery, it is more likely that the PGCs are transferred passively by the morphogenic activity of the lateral-plate mesoderm. Counts of the number of the PGCs revealed that they are mitotically dormant during the migratory period. After the completion of the migration, they regain their proliferative activity. The PGCs in the female proliferate more actively than those in the male, which provides the first morphological indication of sex differentiation in this species of fish.
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    URL: http://dx.doi.org/10.1007/BF00206337
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