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  • Ultrastructure  (116)
  • hypertension  (59)
  • Springer  (175)
  • Cambridge University Press
  • Frontiers Media
  • 2020-2022
  • 1980-1984  (175)
  • 1975-1979
  • 1984  (93)
  • 1982  (82)
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  • 2020-2022
  • 1980-1984  (175)
  • 1975-1979
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 34 (1982), S. 273-279 
    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.
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  • 2
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    Calcified tissue international 36 (1984), S. 550-555 
    ISSN: 1432-0827
    Keywords: Enamel crystals ; Length ; Shape ; Apatite ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary An original method for fractionating and preparing isolated crystals of homogeneous size was developed. It was demonstrated that enamel apatite crystals are at least 100 µm long. The flexibility of the very long crystallites was demonstrated. Crystal curvatures, accounting for the irregular course of the prisms through the enamel thickness, were visualized and measured. It was shown that in the deep forming enamel layer, lateral branches may grow out of the crystals and crystal fusing often occurs, inducing the crystallites to assume pyramidal shapes with their wide bases pointing toward the dentino-enamel junction and one or two tops toward Tomes' processes. During the maturation process, the two tops of the still immature crystals also fuse so that the mature crystals acquire a rodlike aspect, with parallel faces and steplike graduations along thec axis, allowing a close contact between the crystals. These results support the hypothesis that the crystallites would be continuous from the dentino-enamel junction to the surface.
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  • 3
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    Calcified tissue international 34 (1982), S. 382-390 
    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.
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  • 4
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    European journal of clinical pharmacology 21 (1982), S. 287-291 
    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.
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  • 5
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    European journal of clinical pharmacology 21 (1982), S. 363-367 
    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.
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  • 6
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    European journal of clinical pharmacology 22 (1982), S. 7-14 
    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.
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  • 7
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    European journal of clinical pharmacology 22 (1982), S. 197-201 
    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.
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  • 8
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    European journal of clinical pharmacology 22 (1982), S. 495-499 
    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.
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  • 9
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    European journal of clinical pharmacology 26 (1984), S. 309-313 
    ISSN: 1432-1041
    Keywords: clonidine ; hypertension ; therapeutic window ; steady state concentration ; pharmacokinetics ; cardiovascular effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Clonidine was given orally as monotherapy in increasing daily doses from 3.1 to 25.7 µg/kg to patients with essential hypertension (n=6). When a steady state concentration in plasma was reached at each dose level, the blood pressure (BP) and heart rate were measured during a dosage interval. Effect time — plasma concentration data were submitted to nonlinear regression analysis, which showed that the observed BP effects could be dissociated into depressor and pressor components. A window for the antihypertensive effect was established. At a plasma clonidine concentration of 0.65±0.07 ng/ml 50% of the maximal depressor effect was found, and it was only separated by a factor of 2 from the half maximal pure pressor concentration in plasma. No relationship between the change in heart rate and the plasma clonidine was observed. The findings strengthen the importance of close monitoring of clonidine therapy.
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  • 10
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    European journal of clinical pharmacology 26 (1984), S. 331-334 
    ISSN: 1432-1041
    Keywords: metoprolol ; oxprenolol ; hypertension ; beta-blockers ; HDL-cholesterol ; intrinsic sympathomimetic activity ; cardioselectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The aim of the present study was to evaluate whether a reduction in HDL-cholesterol is peculiar to non cardioselective beta blockers or whether it is also produced by cardioselective beta1-blockers. 16 patients with primary arterial hypertension on a balanced isocaloric diet were given oxprenolol 120 to 240 mg/day or metoprolol 100 to 200 mg/day in a random cross-over study. No significant change was observed after either treatment in fasting blood glucose, serum total cholesterol and triglycerides. HDL-cholesterol concentration was significantly decreased on metoprolol, from 41 to 36 mg/dl (p〈0.05), while oxprenolol did not affect it at all. The difference might depend on intrinsic sympathomimetic activity which is possessed by oxprenolol and which metoprolol lacks.
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  • 11
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    European journal of clinical pharmacology 26 (1984), S. 549-553 
    ISSN: 1432-1041
    Keywords: pafenolol ; hypertension ; antihypertensive therapy ; beta1-blocking agent ; exercise tests ; plasma levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Pafenolol, a new selective adrenergic beta1-blocking agent, has been tested for the first time in 6 hypertensive patients. After single oral doses of pafenolol 25 to 100 mg, there was a marked reduction in heart rate and systolic blood pressure during exercise tests. These effects were dose dependent. A significant positive correlation was found between the reduction in heart rate during exercise and the plasma level of pafenolol 5 hours after drug intake (correlation coefficient r=0.94). Side effects were mild and seemed to be dose dependent. It is concluded that this new beta1-blocking agent was effective in reducing blood pressure and was well tolerated.
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  • 12
    ISSN: 1432-1041
    Keywords: etozolin ; ozolinone ; furosemide ; hypertension ; renin ; catecholamines ; chronic renal failure ; steady state kinetics ; plasma levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect on urinary electrolyte excretion, renin release and plasma norepinephrine of single oral doses of 400 mg etozolin (E) and of 40 mg furosemide (F) were studied in hypertensive patients with normal (n=6) and impaired kidney function (n=6). E caused a marked saluresis up to 24 hours, showing its long duration of action. F, however, displayed a brief, brisk peak diuresis, followed by a rebound from the 4th to the 24th hours. The brisk peak diuresis induced by F was associated with pronounced release of renin, almost twice that induced by E. In chronic renal failure the renin release in relation to the magnitude of the diuresis was increased, i.e. the sensitivity of these patients to changes in water homeostasis was increased. E and F stimulated the sympathetic system to roughly the same extent. Patients with essential hypertension had higher plasma levels of norepinephrine than hypertensive patients with chronic renal failure. In addition, hypertensive patients with normal renal function (n=4) and varying degrees of renal impairment (n=11) were also given 400 mg daily for 2 weeks. Effects on blood pressure and electrolyte homeostasis were monitored, as well as the plasma kinetics of metabolite I, ozolinone. At the end of the 2 week treatment E had significantly lowered systolic (−12 mm Hg) and diastolic (−9 mm Hg) blood pressure, and had produced a significant loss of body weight, without altering plasma electrolytes or blood chemistry. There was no accumulation of the effective metabolite ozolinone under conditions of severe impairment of kidney function. It is concluded that E can effectively control high blood pressure in patients with normal and impaired kidney function. Its effective metabolite ozolinone did not accumulate in chronic renal failure.
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  • 13
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    European journal of clinical pharmacology 27 (1984), S. 397-405 
    ISSN: 1432-1041
    Keywords: indapamide ; hypertension ; cardiovascular reflexes ; diuretic effect ; blood pressure variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Nine elderly and 11 young hypertensives underwent continuous ambulatory monitoring of blood pressure (BP), assessment of cardiovascular reflexes and M-mode echocardiography as hospital in-patients prior to treatment with once-daily indapamide (2.5 mg). They were followed as out-patients for 4 months during which time casual BP was measured at monthly intervals. The patients were then readmitted to hospital and studied using the same protocol under similar standardised conditions. The results showed that indapamide reduced casual and ambulatory BP in both young and elderly although the most marked effect was seen on systolic BP. Assessment of cardiovascular reflexes indicates that at least part of the hypotensive action of indapamide is due to a diuretic effect. Treatment with indapamide has comparable results on both young and elderly.
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  • 14
    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.
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  • 15
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    European journal of clinical pharmacology 21 (1982), S. 445-449 
    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.
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  • 16
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    European journal of clinical pharmacology 21 (1982), S. 473-477 
    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.
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  • 17
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    European journal of clinical pharmacology 22 (1982), S. 285-288 
    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.
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  • 18
    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.
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  • 19
    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.
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  • 20
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    European journal of clinical pharmacology 23 (1982), S. 197-201 
    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.
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  • 21
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    European journal of clinical pharmacology 23 (1982), S. 215-220 
    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.
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  • 22
    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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  • 23
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    European journal of clinical pharmacology 26 (1984), S. 315-323 
    ISSN: 1432-1041
    Keywords: captopril ; hypertension ; glomerular filtration ; para-aminohippuric acid ; renal function ; severe drug reaction ; nephrotic syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of captopril up to 450 mg/day on blood pressure and renal function were investigated during sustained treatment of 10 patients whose severe hypertension had not responded to previous therapy. All the patients were kept on diuretics and most of them on β-blockers, too. A control determination of glomerular filtration rate (GFR) and para-aminohippuric acid clearance (CPAH) was performed during the prior treatment. The effect of the addition (or substitution) of captopril were assessed after an average of 25 days (short-term) and 26 weeks (long-term). Short-term treatment produced a 15.5% decrease in mean blood pressure and interindividually variable effects on renal function. On average GFR was somewhat lower and CPAH slightly higher than the control values (not significant). This pattern is quite similar to the effects of most other antihypertensive drugs. On long-term therapy GFR rose by a mean of 9% (NS) and CPAH by 17% (p〈0.02). However, in a patient who developed a captopril-induced nephrotic syndrome, GFR dropped to 56% and CPAH to 50% of the control values. In another patient a transient rise in serum creatinine accompanied a severe drug reaction.
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  • 24
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    European journal of clinical pharmacology 21 (1982), S. 263-267 
    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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  • 25
    ISSN: 1432-1041
    Keywords: hypertension ; indapamide ; pindolol ; plasma renin activity ; plasma aldosterone concentration
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    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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  • 26
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    European journal of clinical pharmacology 22 (1982), S. 487-489 
    ISSN: 1432-1041
    Keywords: nadolol ; hypertension ; effective dose range ; compliance
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    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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  • 27
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    European journal of clinical pharmacology 23 (1982), S. 93-97 
    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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  • 28
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    European journal of clinical pharmacology 21 (1982), S. 457-460 
    ISSN: 1432-1041
    Keywords: hypertension ; propranolol ; hydralazine ; labetalol
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    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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  • 29
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    European journal of clinical pharmacology 22 (1982), S. 203-206 
    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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  • 30
    ISSN: 1432-1041
    Keywords: labetalol ; chlorthalidone ; hypertension ; fixed combination ; antihypertensive therapy ; side effects ; multicentre study
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    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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  • 31
    ISSN: 1432-1041
    Keywords: beta-blocking drugs ; insulin sensitivity ; pancreatic beta-cell function ; hypertension ; propranolol ; atenolol ; insulin secretion ; plasma GIP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of two beta-blocking drugs on endogenous insulin secretion and insulin sensitivity were investigated in a double blind cross-over study in 13 hypertensive patients. The patients were randomly allocated to each of three 2-week treatment periods with propranolol 80 mg b.i.d., atenolol 50 mg b.i.d. and placebo b.i.d. Endogenous insulin secretion was assessed by measuring serum insulin and C-peptide before and 6 min after iv administration of glucagon; insulin sensitivity was determined by measuring insulin binding to erythrocytes, and as the glucose disappearance rate (KITT) after i.v. insulin. Fasting concentrations of serum free fatty acids (S-FFA) and plasma gastric inhibitory polypeptide (P-GIP) were also recorded during the three study periods. Both propranolol and atenolol reduced blood pressure, heart rate and S-FFA concentrations compared to placebo, and all patients showed measurable plasma concentrations of propranolol and atenolol. The results can be considered representative, therefore, of clinical beta-blockade. The two drugs did not significantly influence the fasting blood glucose level. There was an increase in fasting and glucagon-stimulated serum C-peptide concentration during propranolol therapy compared with placebo (p=0.037 and p=0.030, respectively), although this was not reflected by a significant change in serum insulin. Propranolol and atenolol did not significantly influence insulin binding to erythrocytes, but they clearly reduced the glucose disappearance rate KITT was compared to placebo (p=0.0036 and p=0.0003, respectively). The findings support the view that beta-blocking drugs can influence glucose metabolism by mechanisms other than inhibition of endogenous insulin secretion.
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  • 32
    ISSN: 1432-1041
    Keywords: acetylator phenotype ; hydralazine response ; hypertension ; blood pressure control ; lupus syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The role of acetylator phenotype in determining the response to hydralazine when it was added to diuretic and β-blocker at doses not exceeding 200 mg daily was examined in 57 hypertensive patients. 81% of rapid acetylators needed 200 mg hydralazine daily compared to 38% of slow acetylators (p〈0.01). Despite higher doses of hydralazine the blood pressure was controlled in only 27% of rapid acetylators compared to 65% of slow acetylators (p〈0.02). The relation of acetylator phenotype to blood pressure response was statistically independent of initial blood pressure, age, sex, body weight and serum creatinine (p〈0.005). Current recommendations on hydralazine dosage are unsatisfactory for the 40% of hypertensive patients who are rapid acetylators. We suggest measurement of the acetylator phenotype in patients who respond incompletely to 200 mg hydralazine daily. About 70% of these patients will be rapid acetylators in whom the dose of hydralazine can be increased safely.
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  • 33
    ISSN: 1432-1041
    Keywords: Tobanum® ; beta-blocker ; chloranolol ; hypertension ; angina pectoris ; arrhythmia ; detection methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The incidence of side-effects on administration of chloranolol (Tobanum®), a beta-adrenergic receptor blocking drug, to 2066 patients with hypertension, angina pectoris or arrhythmias was measured by three different methods. In 600 patients in an efficacy trial (Group 1) both spontaneously reported complaints and objective signs were tabulated. A side effect — directed method, utilising a questionnaire containing a list of possible side-effects was also used, with the questionnaire being completed by the physician. 35 questions referred to anticipated and other side-effects. The trial was performed in two groups: in 537 patients a placebo was also given (Group 2), and in another set of 929 patients (Group 3) the questionnaire inquiry was performed uncontrolled, without placebo. All three groups were comparable in their distribution of sexes, ages and diagnoses, the mean daily dose of chloranolol its use alone or in combination, and in a similar duration of treatment. 55% of all patients received chloranolol therapy for a period of more than 3 months. The ratio of in- and outpatients was 1:5. The side-effect incidence was independent of the age and sex of the patients and of the dose of chloranolol. The incidence was also unaffected whether chloranolol was used alone or in combination. The number of side-effects differed markedly between the three groups, their ratio was 1:10:24 in Groups 1, 2 and 3. Two-thirds of the side-effects subsided spontaneously within 1 month of their onset. The duration of the side-effects varied according to their character: cardiorespiratory side-effects were of the shortest duration and those affecting the central nervous system were the most enduring. The appreciable differences in incidence could be attributed to the methods of collection of the data. It has been stated that placebo controlled trials using a detailed questionnaire are the most suitable for estimating the incidence of side-effects; recording side-effects spontaneously reported by patients are insufficiently sensitive, and uncontrolled trials using a questionnaire have been shown to be too sensitive. The revealed incidence of side effects leading to interruption of treatment is less affected by the method chosen. In 100 patients (4.8%) therapy had to be suspended because of the side-effects of chloranolol (Group 1: 1%, Group 2: 6.20%, Group 3: 6.6%). Comparison of the incidence of cessation of therapy due to side-effects did not show an appreciable difference between the various beta-adrenergic receptor blocking agents, including chloranolol.
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  • 34
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    European journal of clinical pharmacology 26 (1984), S. 1-6 
    ISSN: 1432-1041
    Keywords: hypertension ; beta-blockers ; propranolol ; metoprolol ; labetalol ; exercise ; heart rate ; blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a double blind, within patient investigation of twenty-four patients (nineteen males and five females) with a mean age of 46.3 years (SD 10.9 years) with mild to moderate essential hypertension a comparison between equipotent beta-blocking doses of propranolol, metoprolol and labetalol was carried out. Blood pressure and pulse rate were measured in lying, sitting and standing positions and before, during and after isometric and dynamic exercise. Peak expiratory flow was recorded before and during dynamic exercise. All the active treatments were better than placebo in reducing blood pressure and heart rate. Comparing the effects of treatment, labetalol lowered sitting diastolic pressure significantly more than propranolol and standing diastolic pressure than both propranolol and metoprolol. Metoprolol and propranolol were more effective in reducing heart rate. Propranolol significantly reduced peak flow rate compared to labetalol. During the exercise, both isometric and dynamic, the heart rate and the blood pressure, both systolic and diastolic, of the treated patients were lower than those on placebo. There was little difference between the drugs in the influence on blood pressure, but metoprolol and propranolol were significantly more effective than labetalol in lowering the heart rate.
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  • 35
    ISSN: 1432-1041
    Keywords: alpha-methyldopa ; propranolol ; hypertension ; side effects ; blood pressure control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A multicentre study of 6–10 weeks duration was performed in 60 ambulant hypertensive patients aged over 60 years to compare the efficacy of methyldopa and propranolol with particular reference to the occurrence of cold extremities and sleep disturbances. Blood pressure was effectively controlled by both drugs being reduced from a mean of 180/108 mmHg to 161/93 with methyldopa and 180/108 to 162/94 with propranolol. More patients treated with methyldopa (74%) achieved the target diastolic blood pressure of 95 mmHg or below compared with those treated with propranolol (58%). Side effects were more frequent in the propranolol group necessitating the withdrawal of four patients from the study. Only one patient on methyldopa was withdrawn. The incidence of cold extremities was significantly greater with propranolol. The occurrence of sleep disturbances was similar in both groups. In this group of elderly patients methyldopa was better tolerated than propranolol.
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  • 36
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    European journal of clinical pharmacology 26 (1984), S. 543-547 
    ISSN: 1432-1041
    Keywords: indapamide ; hypertension ; glomerular filtration ; arginine vasopressin ; free water clearance ; blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Renal plasma flow (RPF), glomerular filtration rate (GFR), arginine vasopressin in plasma (AVP), free water clearance ( $${\text{C}}_{{\text{H}}_{\text{2}} {\text{O}}}$$ ) and blood pressure (BP) were determined in 11 patients with essential hypertension at the end of 3 consecutive periods of observation each of 6 of weeks duration; indapamide 2.5 mg daily was given in period 2 and placebo in periods 1 and 3. RPF and GFR were reduced by 9% and BP by 9%/14% supine and 14%/12% standing during indapamide treatment. Changes in renal haemodynamics were not correlated with those in BP. AVP was not significantly altered by indapamide and was not correlated with BP. Indapamide reduced $${\text{C}}_{{\text{H}}_{\text{2}} {\text{O}}}$$ possibly due to the reduction in GFR. It is concluded that indapamide evidently induces redistribution of the cardiac output, with enhanced muscle blood flow and reduced renal perfussion, and that AVP does not seem to be involved in blood pressure regulation in mild to moderate essential hypertension under basal conditions.
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  • 37
    ISSN: 1432-1041
    Keywords: beta-blockers ; hypertension ; ISA ; CS ; cold extremities
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Patients with essential hypertension were interviewed prior to entering therapeutic studies in general practice. Patients' age, sex and details of antihypertensive therapy (if any) were noted, as were their spontaneously reported symptoms. Complaints of cold extremities were highest in those taking a beta-blocker (4.1%). Those untreated or taking other therapies complained less often. Those patients taking a beta-blocker with ISA complained less often (3.1%) of cold extremities than those taking a beta-blocker without ISA (5.2%).
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  • 38
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    European journal of clinical pharmacology 27 (1984), S. 13-17 
    ISSN: 1432-1041
    Keywords: nifedipine ; hypertension ; blood pressure decrease ; drug combination
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The medication of patients receiving hydralazine, captopril and minoxidil was replaced by a new galenical form, long-acting nifedipine. An additional decrease in blood pressure was observed in most of the patients. Renal function was maintained in all of them. Adverse reactions may be reduced by the use of long-acting nifedipine, which would permit a reduction in the dosage of captopril and minoxidil.
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  • 39
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    European journal of clinical pharmacology 27 (1984), S. 23-27 
    ISSN: 1432-1041
    Keywords: hypertension ; alpha2-adrenoceptors ; blood pressure ; clonidine ; guanfacine ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The time courses of the changes in plasma growth hormone and noradrenaline concentrations in response to 15 min infusions of clonidine 0.2 mgs and guanfacine 2 mgs, were studied in six normal volunteers, in a double-blind, randomised, crossover study. Plasma noradrenaline fell within 15 min of the commencement of drug administration, by 36±14% after clonidine (p〈0.05) and by 32±11% (p〈0.05) after guanfacine. Plasma growth hormone was not significantly elevated until the 30th minute to 12.0±4.7 lU/ml (p〈0.05) after clonidine and 14.7±11.5 lU/ml (p〈0.05) after guanfacine, having been undetectable prior to both drugs. The reduction in plasma noradrenaline by these α2-adrenergic agonists, prior to activation of central adrenoceptors as detected by changes in plasma growth hormone, is evidence for a peripheral component in their sympatholytic effect.
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  • 40
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    European journal of clinical pharmacology 27 (1984), S. 147-152 
    ISSN: 1432-1041
    Keywords: moxonidine ; clonidine ; hypertension ; double-blind crossover ; side-effects ; withdrawal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive effect of moxonidine·HCl·H2O (MOX) was compared with that of clonidine·HCl (CLON) in a randomized double-blind crossover study in 20 hypertensive outpatients (BP range 154–178/96–108 mmHg). After 2 weeks without antihypertensive medication, either MOX 0.2 mg daily or CLON 0.2 mg daily was given and the dose was titrated until the diastolic blood pressure fell below 90 mmHg. The first treatment period was continued for 2 weeks and, after crossover without a wash-out period, it was followed by the second treatment for a further 2 weeks. Within the first 4 days of administration 0.2–0.4 mg of either agent caused a significant decrease in BP (p〈0.001) from a mean of 166/100 mmHg to 149/86 mmHg after CLON (approx. −10/−14%), and 163/99 mmHg to 146/84 mmHg after MOX (approx. −10/−15%). No significant difference in the fall in BP or pulse rate was detected between the two drugs. In the mean daily dose of 0.3 mg both drugs showed the same antihypertensive activity, but on CLON a higher incidence of side effects (p=0.003) was noted, and after discontinuation of therapy a more rapid rise in BP (systolic BP p〈0.01, diastolic BP p〈0.02) was found. 17 patients on CLON complained of side effects, especially tiredness and dry mouth, whilst only 6 patients on MOX were affected (p=0.003).
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  • 41
    ISSN: 1432-1041
    Keywords: guanfacine ; hydrallazine ; hypertension ; sympathetic nervous activity ; plasma renin activity ; cardiac and systemic haemodynamics ; blood pressure ; limb blood flow ; limb vascular resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of guanfacine and hydrallazine on cardiovascular haemodynamics and on sympathetic nervous activity has been studied in 16 patients with essential hypertension. Two groups of patients were investigated: in Group A guanfacine brought the blood pressure back to normal (diastolic blood pressure ⩽90 mmHg), and in Group B diastolic blood pressure was 〉 90 mmHg and required the addition of hydrallazine. Guanfacine significantly decreased heart rate, plasma renin activity and urinary excretion of noradrenaline, without altering cardiac contractility. In Group B, guanfacine 2 to 6 mg/day produced a significant decrease in blood pressure from 178.7/112.4 to 164.4/102.9 mmHg and in heart rate from 77.1 to 62.7 beats/min after 4 weeks of treatment. Guanfacine did not significantly alter preejection period, cardiac output or total peripheral resistance. Hydrallazine 50 to 300 mg/day caused a further reduction in blood pressure from 164.4/102.9 to 150.7/90.2 mmHg and an increase in heart rate from 62.7 to 72.1 beats/min. Limb blood flow was increased from 4.55 to 5.93 ml/100 g/min and limb vascular resistance was decreased from 39.55 to 23.6 mmHg 100 g·min/ml. Hydrallazine also caused a slight increase in plasma renin activity and urinary excretion of noradrenaline. It is concluded that guanfacine is a useful agent to block a hydrallazine-induced increase in sympathetic nervous activity.
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  • 42
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    European journal of clinical pharmacology 27 (1984), S. 407-414 
    ISSN: 1432-1041
    Keywords: piretanide ; hypertension ; triamterene ; double blind comparison ; potassium ; magnesium ; side-effects ; serum electrolytes ; serum parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a randomized, double blind, parallel group study in out patients with mild to moderate essential hypertension the effects of piretanide on serum electrolytes and on blood pressure were compared with those of triamterene alone and the combination piretanide + triamterene. 136 patients entered the study; 18 patients did not fulfill the inclusion criteria (RRdiast was below 95 mmHg or above 120 mmHg) at the end of the placebo period, 6 dropped out due to side effects, and 1 due to lack of efficacy. Data from 1 patient were not evaluated because the patient did not come regularly for checkups. The results for 110 patients were analyzed. Piretanide 6 mg b.d. and piretanide 6 mg + triamterene 50 mg b.d. produced a significant reduction both in supine and erect blood pressure, which was evident at 2 weeks and which increased over the ensuing 12 week trial period. A mean maximal fall of 16.5% was noted in the piretanide group and 15% in the piretanide + triamterene group. Triamterene alone (50 mg b.d.) also reduced diastolic and systolic blood pressures but the reduction was significantly less (diastolic blood pressure) than in both the piretanide groups, and it showed a more rapid return to pretreatment level during a placebo washout phase at the end of the study. A reduction in standing diastolic blood pressure below 95 mmHg was attained in 84% of patients in the piretanide group, 82% in the piretanide + triamterene group and in only 58% of the triamterene group. There were no significant changes within groups nor differences between the three groups in serum potassium or magnesium. 7 patients were withdrawn from the study because of side-effects due to too marked a clinical action (polyuria, orthostatic disorders and hypotension), one from the piretanide group, and the others in the piretanide + triamterene group. One patient in the triamterene group left the study prematurely due to the lack of effect.
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  • 43
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    European journal of clinical pharmacology 27 (1984), S. 529-534 
    ISSN: 1432-1041
    Keywords: beta-adrenoceptor blocking agents ; hypertension ; adverse reactions ; atenolol ; bopindolol ; pindolol
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The efficacy of once-daily bopindolol, a nonselectiveβ-adrenoceptor blocking agent with partial agonist activity, and of pindolol and atenolol in the treatment of essential hypertension has been compared. 369 patients were investigated in a double-blind parallel-group study. The treatment period was 10 weeks. Blood pressure normalisation (diastolic BP equal to or less than 90 mmHg) was to be achieved by a stepwise increase in the dose of the test drugs, and, if required, by addition of a diuretic. Normalisation of blood pressure was achieved in 71 to 76% of the subjects, with no significant differences between bopindolol, pindolol, and atenolol. Special attention was given to evaluation of side effects by using two methods for registration of all adverse events during the study. A low incidence of drug-induced side effects was observed, with no significant difference between bopindolol, pindolol, and atenolol. There was no evidence of unsuspected adverse reactions due to bopindolol.
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  • 44
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    European journal of clinical pharmacology 21 (1982), S. 389-390 
    ISSN: 1432-1041
    Keywords: nifedipine ; metoprolol ; hypertension ; calcium antagonist ; side effects
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    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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  • 45
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    European journal of clinical pharmacology 22 (1982), S. 95-99 
    ISSN: 1432-1041
    Keywords: penbutolol ; hypertension ; primary hypertension ; blood pressure response ; plasma concentration
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    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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  • 46
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    European journal of clinical pharmacology 23 (1982), S. 403-409 
    ISSN: 1432-1041
    Keywords: alpha-2-adrenoceptors ; hypertension ; clonidine ; human platelets ; 3H-yohimbine binding ; receptor regulation ; clonidine withdrawal ; desensitization ; GTP
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    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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  • 47
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    European journal of clinical pharmacology 23 (1982), S. 491-494 
    ISSN: 1432-1041
    Keywords: betaxolol ; hypertension ; double-blind trial ; cross-over trial
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    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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  • 48
    ISSN: 1432-1041
    Keywords: prizidilol ; hypertension ; side effects ; chronic treatment ; antihypertensive effect ; anaemia
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    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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  • 49
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    European journal of clinical pharmacology 22 (1982), S. 379-381 
    ISSN: 1432-1041
    Keywords: propranolol ; hypertension ; elderly patients ; long-acting propranolol
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    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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  • 50
    ISSN: 1432-1041
    Keywords: hypertension ; hydrochlorothiazide ; atenolol ; side effects ; therapeutic efficacy
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After screening a local population in the northern part of The Netherlands for hypertension, 119 patients with a diastolic pressure (DP) between 95 and 120 mmHg were randomised and treated either with 50 mg hydrochlorothiazide (n=59) or 100 mg atenolol (n=60). After 1 month of treatment 6 patients in the hydrochlorothiazide group and 24 patients in the atenolol group had reached a DP⩽90 mmHg (p〈0.001). 43 of the 50 non-responders to hydrochlorothiazide were switched to atenolol and 30 of the 35 non-responders to atenolol were changed to hydrochlorothiazide. One month after the switch 19 patients in the atenolol group and 2 patients in the hydrochlorothiazide group had reached a DP⩽90 mmHg (p〈0.001). After 6 months of treatment 32 of the 43 atenolol responders and 7 of the 8 hydrochlorothiazide responders were still receiving the same medication, as their DP was still⩽90 mmHg. Non-responders to either medication were given the combination (n=46). 21 patients now became normotensive as did a further 10 after increasing the dose of atenolol to 200 mg. Thus, in all 70 patients had a blood pressure ⩽90 mmHg after treatment for 4 months. Both drugs induced a significant reduction in the total of number of complaints after 1 month of treatment. They did not differ from each other. The reduction was seen both in responders and non-responders and persisted during treatment for 6 months. It is concluded that in terms of short-term efficacy the cardioselective, hydrophilic beta adrenoceptor-blocking drug atenolol is preferable to hydrochlorothiazide in the treatment of uncomplicated hypertension.
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  • 51
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    European journal of clinical pharmacology 23 (1982), S. 397-401 
    ISSN: 1432-1041
    Keywords: hypertension ; prazosin ; alpha-adrenoceptors ; alpha-blocking drugs ; UK-33,274
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    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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  • 52
    ISSN: 1432-1041
    Keywords: carprazidil ; minoxidil ; hypertension ; catecholamines ; renin ; aldosterone ; blood volume ; hypertrichosis ; side effects
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    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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  • 53
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    European journal of clinical pharmacology 26 (1984), S. 603-608 
    ISSN: 1432-1041
    Keywords: pinacidil ; hypertension ; pinacidil pyridine-N-oxide ; urinary excretion ; protein binding ; pharmacokinetics ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Preliminary investigation in 3 healthy volunteers suggested that intravenous pinacidil in a dose of 0.2 mg/kg had a potent but well-tolerated hypotensive action in the supine position. Facial flushing, uncomfortable chest sensation and distressing postural hypotension occurred at serum concentrations above 300 ng/ml. Pinacidil, 0.2 mg/kg, was given intravenously over 4 min to 15 healthy volunteers in the supine position. Maximum fall in mean arterial pressure (MAP) was 15.7±6.0 mmHg. Maximum rise in heart rate was 23.8±6.6 beats/min. Pinacidil serum distribution half-life ( $${\text{T}}_{{\raise0.7ex\hbox{${\text{1}}$} \!\mathord{\left/ {\vphantom {{\text{1}} {{\text{2}}\alpha }}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${{\text{2}}\alpha }$}}}$$ ) was 13.4±8.5 min and elimination half-life ( $${\text{T}}_{{\raise0.7ex\hbox{${\text{1}}$} \!\mathord{\left/ {\vphantom {{\text{1}} {{\text{2}}\beta }}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${{\text{2}}\beta }$}}}$$ ) was 2.13±0.49 h. The apparent volume of distribution (Vdβ) was 90.3±13.21 and total body clearance was 31.1±9.61/h. Pinacidil was approximately 40% bound to plasma protein over the concentration range 40–400 ng/ml. Urinary excretion of unchanged pinacidil accounted for 5.7 ± 1.3% of the administered dose over 24 hours and urinary excretion of the major metabolite, pinacidil pyridine-N-oxide, was 31.6±9.2% of the administered dose. It was concluded that intravenous pinacidil is a potent vasodilator hypotensive compound, with a duration of action between 1.5 and 2 h.
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  • 54
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    European journal of clinical pharmacology 26 (1984), S. 661-661 
    ISSN: 1432-1041
    Keywords: endralazine ; hypertension ; elimination half-liefe ; compartment model
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  • 55
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    European journal of clinical pharmacology 27 (1984), S. 13-17 
    ISSN: 1432-1041
    Keywords: nifedipine ; hypertension ; blood pressure decrease ; drug combination
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The medication of patients receiving hydralazine, captopril and minoxidil was replaced by a new galenical form, long-acting nifedipine. An additional decrease in blood pressure was observed in most of the patients. Renal function was maintained in all of them. Adverse reactions may be reduced by the use of long-acting nifedipine, which would permit a reduction in the dosage of captopril and minoxidil.
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  • 56
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    European journal of clinical pharmacology 27 (1984), S. 23-27 
    ISSN: 1432-1041
    Keywords: hypertension ; alpha2-adrenoceptors ; blood pressure ; clonidine ; guanfacine ; healthy volunteers
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The time courses of the changes in plasma growth hormone and noradrenaline concentrations in response to 15 min infusions of clonidine 0.2 mgs and guanfacine 2 mgs, were studied in six normal volunteers, in a double-blind, randomised, crossover study. Plasma noradrenaline fell within 15 min of the commencement of drug administration, by 36±14% after clonidine (p〈0.05) and by 32±11% (p〈0.05) after guanfacine. Plasma growth hormone was not significantly elevated until the 30th minute to 12.0±4.7 lU/ml (p〈0.05) after clonidine and 14.7±11.5 lU/ml (p〈0.05) after guanfacine, having been undetectable prior to both drugs. The reduction in plasma noradrenaline by these α2-adrenergic agonists, prior to activation of central adrenoceptors as detected by changes in plasma growth hormone, is evidence for a peripheral component in their sympatholytic effect.
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  • 57
    ISSN: 1432-1041
    Keywords: beta-blockers ; hypertension ; ISA ; CS ; cold extremities
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Patients with essential hypertension were interviewed prior to entering therapeutic studies in general practice. Patients’ age, sex and details of antihypertensive therapy (if any) were noted, as were their spontaneously reported symptoms. Complaints of cold extremities were highest in those taking a beta-blocker (4.1%). Those untreated or taking other therapies complained less often. Those patients taking a beta-blocker with ISA complained less often (3.1%) of cold extremities than those taking a beta-blocker without ISA (5.2%).
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  • 58
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    European journal of clinical pharmacology 27 (1984), S. 287-289 
    ISSN: 1432-1041
    Keywords: pinacidil ; hypertension ; vasodilator ; patients ; side-effects
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A new vasodilator drug, pinacidil, N″-cyano-N-4-pyridyl-N′-1, 2,2-trimethylpropylguanidine, was studied in an open trial in 15 patients with moderate to severe hypertension. Four patients received pinacidil monotherapy, and in 11 patients it was used with a diuretic or a beta-blocker. In all but one patient normotension was achieved with a mean daily pinacidil dose of 46.7 mg b.i.d. (range 20–100 mg). Side effects were few and were action-related. There was no evidence of early toxicity. Pinacidil is a promising new antihypertensive vasodilator, which deserves further clinical evaluation.
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  • 59
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    Archives of microbiology 133 (1982), S. 11-19 
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
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    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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  • 60
    ISSN: 1432-072X
    Keywords: Methanogenium tatii ; Ultrastructure ; Physiology ; Glycoproteins ; DNA-DNA Homology ; Taxonomy ; Archaebacteria
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    Topics: Biology
    Notes: Abstract A new coccoid methanogen, Methanogenium tatii, was isolated and characterized. The mesophilic isolate can grow on and produce methane from H2:CO2 and formate. For growth acetate is strictly required. The cell shape, the G+C content of 54 mol% and DNA-DNA homology data suggest it to be a Methanogenium species.
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  • 61
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    Archives of microbiology 138 (1984), S. 229-232 
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces torulosus ; Morphology ; Ultrastructure ; Verrucate spores ; Knobby ornamentation ; Sheath
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    Topics: Biology
    Notes: Abstract The type strain of Streptomyces torulosus Lyons and Pridham (1971) was studied by scanning- and transmission electron microscope. Spore chains were formed in spirals by aerial mycelium. The spores were connected by nozzles in which small channels could be observed. The knobby ornamentations of the spores arised on a thin fibrous sheath, enveloping the spore chains. These irregular blunt projections, called knobs, had varying diameters of 100 to 250 nm. The base of the knob, consisting of globose to flattened electron dense material, was sitting directly on the sheath. It was covered by several small vesicles of the same material. Each hollow vesicle beared a thin bowlshaped shell of electron transparent material. In general, the cupular bowls and their supporting vesicles became easily depressed on their base, but not detached from the surface of the spores. This type of knobby spore ornamentation was suggested to be designated as a verrucate spore type.
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  • 62
    ISSN: 1432-072X
    Keywords: Nitrobacter hamburgensis ; Nitrite oxidoreductase ; Nitrate reductase ; Molybdenum iron-sulfur protein ; Ultrastructure
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    Topics: Biology
    Notes: Abstract Nitrite oxidoreductase, the essential enzyme complex of nitrite oxidizing membranes, was isolated from cells of the nitrifying bacterium Nitrobacter hamburgensis. The enzyme system was solubilized and purified in the presence of 0.25% sodium deoxycholate. Nitrite oxidoreductase oxidized nitrite to nitrate in the presence of ferricyanide. The pH optimum was 8.0, and the apparent K m value for nitrite amounted to 3.6 mM. With reduced methyl-and benzylviologen nitrite oxidoreductase exhibited nitrate reductase activity with an apparent K m value of 0.9 mM for nitrate. NADH was also a suitable electron donor for nitrate reduction. The pH optimum was 7.0. Treatment with SDS resulted in the dissociation into 3 subunits of 116,000, 65,000 and 32,000. The enzyme complex contained iron, molydbenum, sulfur and copper. A c-type cytochrome was present. Isolated nitrite oxidoreductase is a particle of 95±30 Å in diameter.
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  • 63
    ISSN: 1432-234X
    Keywords: Ultrastructure ; Gills ; Epithelial cells ; Polychaeta
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    Topics: Biology
    Notes: Summary The ultrastructure of gill epidermal cells of Diopatra neapolitana and their relationship with blood spaces are described. The existence of a basal infolding complex, related to the blood spaces, is also reported. A possible involvement of these cells in osmoregulation and ion interchange, apart from their well-known role in respiration, is suggested.
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  • 64
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    Theoretical and applied genetics 68 (1984), S. 305-309 
    ISSN: 1432-2242
    Keywords: Impatiens ; Microspore mitosis ; Plastid distribution ; Ultrastructure
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    Topics: Biology
    Notes: Summary This paper describes the unequal distribution of plastids in the developing microspores of Impatiens walleriana and Impatiens glandulifera which leads to the exclusion of plastids from the generative cell. During the development from young microspore to the onset of mitosis a change in the organization of the cytoplasm and distribution of organelles is gradually established. This includes the formation of vacuoles at the poles of the elongate-shaped microspores, the movement of the nucleus to a position near the microspore wall in the central part of the cell, and the accumulation of the plastids to a position near the wall at the opposite side of the cell. In Impatiens walleriana, the accumulated plastids are separated from each other by ER cisterns, and some mitochondria are also accumulated. In both Impatiens species, the portion of the microspore in which the generative cell will be formed is completely devoid of plastids at the time mitosis starts.
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  • 65
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    Cell & tissue research 235 (1984), S. 309-318 
    ISSN: 1432-0878
    Keywords: Ascidian ; Gut ; Cell involution ; Ultrastructure ; Phagocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Degenerative changes in the digestive tract of zooids of Botryllus schlosseri were studied by light and electron microscopy. Three main processes occurred in the tissues: contraction, involution and phagocytosis. The contraction of epidermis and peribranchial epithelium in which cytoplasmic microfilaments probably participate, seemed to have a special role in compressing the underlying organs. During contraction most of the body cavities collapsed, the branchial walls disintegrated and the fragments were rapidly taken up by large phagocytes. The gut epithelium retained its apparent continuity longer, though isolated phagocytes infiltrated it to eliminate single cells. Cell degeneration came about chiefly either through swelling and lysis of cells or through loss of water and condensation of cytoplasm and nucleus. The fate of all regressed tissues was to be engulfed and digested by wandering phagocytes. However, it was also observed that numerous cells of different epithelia could act as fixed phagocytes by engulfing cell debris and entire cells into heterophagic vacuoles.
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  • 66
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    Cell & tissue research 235 (1984), S. 347-356 
    ISSN: 1432-0878
    Keywords: Blastocyst ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Between days 8 and 11 of pregnancy spherical blastocysts from 0.3 to 10 mm in diameter were flushed from the uterine horns of Dutch Landrace pigs. A description of their ultrastructure is given, and the uptake of horseradish peroxidase and ferritin is demonstrated. The ultrastructure of the trophoblast was similar at all ages studied. The trophoblast which has many apical microvilli is able to take up and digest the macromolecules which were offered in the in vitro incubation medium. The hypoblast consists of flattened cells. In blastocysts 2 mm and larger, compact cells bearing microvilli are found below the embryoblast. Cell organelles indicating protein synthesis are found within hypoblast cells of such blastocysts. In the embryoblast, local concentrations of cell organelles are visible, indicating that differentiation has started. After the disappearance of Rauber's layer, which takes place when the blastocyst reaches a diameter of about 2 mm, superficial embryoblast cells develop short microvilli. The cells do not absorb ferritin or peroxidase but are dependent on the trophoblast for their food requirements. All cell layers in the blastocyst contain mitochondria that have characteristics of those found in steroidproducing cells. The significance of the uptake and digestion of macromolecules by trophoblast cells, the synthesis of protein by hypoblast cells and the possible synthesis of steroids is discussed with respect to the relationship between the cell layers of the blastocyst and in the context of conceptomaternal relationships.
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  • 67
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    Cell & tissue research 236 (1984), S. 365-372 
    ISSN: 1432-0878
    Keywords: Skeletal muscles ; Myofibrils ; Ultrastructure ; Exertion ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of muscle fibres from m. vastus lateralis of nine healthy males (mean age 26 years) was investigated. Four individuals constituted non-exercised controls while five subjects participated in a two-months eccentric muscular training program. Specimens from the controls showed a well-preserved, regular myofibrillar band pattern while changes in the myofibrillar architecture were constantly found in specimens taken after the training program. These changes consisted of Z-band alterations, Z-bands being out of register, extra sarcomeres, Z-band extensions and bisected Z-bands. Between the separated Z-band halves, thin and thick myofilaments as well as abundant glycogen particles and/or ribosomes, were observed. Type-2 (fast-twitch) fibres were predominantly affected. Contrary to the controls the trained individuals constantly showed a greater variation in sarcomere lengths in Type-2 fibres than in Type-1 fibres. It is concluded that muscular work of high tension can induce fine-structural alterations. When repeated over a long period of time, extreme tension demands seem to initiate reorganization in the muscle fibres, predominantly in the, ultrastructurally defined, Type-2 fibres. This adaptation probably results in a better stretchability of the muscle fibres, reduces the risk for mechanical damage and brings about an optimal overlap between actin and myosin filaments.
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  • 68
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    Cell & tissue research 236 (1984), S. 393-397 
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Salamander, Amphiuma ; Ultrastructure ; Stereology ; Volume: surface area ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and stereological examination was performed on stomach smooth muscle of the salamander Amphiuma. This tissue has very large cells, ranging up to 12×1500 μm when relaxed. The extracellular space is 31% of the tissue volume, and the tissue contains 84.6% water. These values are similar to those of other amphibian and mammalian gastrointestinal smooth muscle. The cells possess the usual smooth muscle organelles. Thick, thin and intermediate filaments are present, along with membrane-associated and cytoplasmic dense regions. There is a well-developed sarcoplasmic reticulum and many microtubules. Caveolae are found in rows along the cellular surface; the caveolae increase the cellular surface area by about 70%. The ratio mean volume: surface area of the cells is 1.26 μm. This tissue appears to be typical of gastrointestinal smooth muscle, with the exception of the very large size of the cells.
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  • 69
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    Cell & tissue research 236 (1984), S. 619-628 
    ISSN: 1432-0878
    Keywords: Gastrotricha, freshwater ; Sperm, reduced ; Ultrastructure ; Spermatogenesis ; Temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatogenesis and spermiogenesis in Lepidodermella squammata are confined to the postparthenogenic phase of the life cycle and coincide with developmental changes in the bilateral female gonads. Male stages are bilateral but asynchronous, in the lateral abdomen anterior to the female gonads. Maximum observed sperm production is two packets per side, or 64 sperm. Sperm formation occurs more rapidly at 27° C than at 20° C (p〈0.001), requiring as little as 1 day. Two spermatogonial mitotic divisions produce a clone of four primary spermatocytes connected by bridges (stage 1). Centrioles are absent. Development occurs within a cyst. Meiotic divisions produce 16 spermatids (stage 2), each containing a dense, elongate, tapered nucleus. Cytoplasmic membranes enclose one end of the nuclear rod, excluding all other organelles. Completion of this process results in stage 3, a packet of 16 sperm associated with one dense sphere, a modified ‘residual body’ containing cytoplasmic debris. The residual body then disappears, leaving the sperm packet of stage 4. Each mature sperm is a dense nuclear rod with surrounding membranes, lacking acrosome, mitochondrion, centrioles, and flagellum. Function of sperm has not been demonstrated. The spermatozoa are of a reduced type not previously described.
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    Cell & tissue research 236 (1984), S. 629-636 
    ISSN: 1432-0878
    Keywords: Oocytes, primary ; Gastrotricha, freshwater ; Ultrastructure ; Synaptonemal complex ; X-body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Six small cells are present in each of the bilateral gonads of parthenogenically reproductive Lepidodermella squammata. Early in the extended postparthenogenic phase of the life history, these cells undergo limited proliferation followed by differentiation. Primary oocytes of three types are present 0.3 days after deposition of the final parthenogenic egg: small oocytes with presynaptic nuclei; intermediate oocytes with nuclei containing synaptonemal complexes; and larger oocytes with a germinal vesicle. Oocytes persist without further development at least until day four of the postparthenogenic phase. Older isolated animals may contain and even deposit an enlarged egg, but successful progeny does not result. Oocytes are located at the anterior pole of each of the bilateral gonads, adjacent to developing male tissues producing sperm. More posterior cells in the gonad are initially undifferentated in the postparthenogenic phase. Dorsal and central cells first show specialization for secretory activity, and by day four contain peripheral layers of RER and central accumulations of polymorphic secretion droplets. The posterior and ventral cells produce secretion droplets that aggregate into an enlarging bilobed structure called the X-body. Two or three cells in each gonad contribute secretions to the X-body, which is intracellular in a secondary syncytium formed by the contributing cells. Functions for the postparthenogenic gametes and for the X-body are not yet demonstrated.
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  • 71
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    Cell & tissue research 236 (1984), S. 693-697 
    ISSN: 1432-0878
    Keywords: Intermediate filaments ; Microtubules ; Caveolae ; Bullfrog ; Arachnoid mater ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the bullfrog, the meninges surrounding the central nervous system include an arachnoid mater that contains layers of cells with abundant intermediate filaments (IFs) having unique organizational characteristics. This membrane contains an inner lamina of cells that resemble fibroblasts and an outer lamina of flattened cells that are almost filled with IFs. The IFs of the outer arachnoid are arranged in compact, arching bundles that lie parallel to the outer surface of the central nervous system. Thus, sections cut tangentially to the membrane reveal bending of filament bundles, whereas transverse sections do not. In some cells bordering the subdural space, bundles of filaments are organized into highly-ordered spiral arrays. Attachments to the numerous desmosomes and, apparently, to the nuclear envelope suggest anchoring of cytoplasmic structures by the IF system. Microtubules occur primarily near the plasma membrane and the nucleus. Numerous caveolae also are associated with the plasma membrane. The unusual abundance, organization, and cytoplasmic relations of IFs in the bullfrog arachnoid suggest that this membrane may serve as an important model for study of fundamental cytoskeletal relations and function.
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  • 72
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    Cell & tissue research 237 (1984), S. 277-284 
    ISSN: 1432-0878
    Keywords: Swimbladder ; Teleost ; Cholinergic nerves ; Adrenergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The general structure, ultrastructure and innervation of the swimbladder of the smooth toadfish, Tetractenos glaber, were examined with light-microscopic, fluorescence-histochemical, and transmission electron-microscopic techniques. The structure of the swimbladder is similar to that of other euphysoclists. Fluorescence histochemistry showed adrenergic fibres in both the secretory and resorptive areas of the swimbladder. Transmission electron microscopy revealed two morphologically distinct axon profiles type-I profiles containing many small, flattened vesicles; type-II profiles containing both large, granular vesicles and rounded, small clear vesicles in varying proportions. The gas-gland cells and surrounding muscularis mucosae are innervated by both type-I and type-II fibres. Type-I fibres also innervate pre-rete arteries. The rete- and gas-gland capillaries do not appear to be innervated. Arteries running to the resorptive area are innervated by type-I fibres. Both type-I and type-II profiles make contact with the muscularis mucosae in the resorptive area. Only type-I fibres innervate the radial dilator muscle in the oval sphincter region, whereas only type II fibres innervate the circular muscle of the oval sphincter. Type-I fibres took up α-methyl-noradrenaline, and could not be found after pre-treatment with 6-hydroxydopamine. They are, therefore, assumed to be adrenergic. Type-II fibres were tentatively identified, by exclusion, as cholinergic.
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    Cell & tissue research 237 (1984), S. 537-547 
    ISSN: 1432-0878
    Keywords: Scale ; Regeneration ; Ultrastructure ; Cichlid ; Hemichromis bimaculatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scale regeneration has been studied in Hemichromis bimaculatus. The removed scale, which serves as a control, is covered by its surrounding scleroblasts as can be seen with scanning electron microscopy. Subsequently, during regeneration, a population of scleroblasts arises in the empty dermal pocket as shown with transmission electron microscopy. At first, an elongated papilla of regeneration forms, probably from the differentiation of dermal fibroblasts. A scale anlage composed of the osseous layer appears in the middle of the papilla, which becomes a regenerating bag. All the surrounding large scleroblasts are involved in scale formation, although later three populations of scleroblasts specialize according to their location around the scale. Superficial scleroblasts flatten when the final thickness of the osseous layer of the scale is attained; the deep scleroblasts are responsible for the formation of the basal plate whereas marginal scleroblasts increase the diameter of the osseous layer of the scale. During scale regeneration, scleroblasts are more numerous and larger than during scale ontogenesis. In particular, deep scleroblasts form a columnar epithelium when the basal plate is laid down, a feature which is not found during scale ontogenesis. Moreover, the regenerated basal plate exhibits an orthogonal “plywood” arrangement that is never seen in the embryonic scale where the “plywood” is of the intermediate type.
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  • 74
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    Keywords: Epididymis (marsupials) ; Ultrastructure ; Sperm maturation
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    Notes: Summary The ductus epididymidis of the tammar is lined by an epithelium composed of principal, mitochondria-rich, apical and basal cells, and intraepithelial leucocytes. The epithelium is structurally differentiated into 6 zones referred to as the initial segment, middle segment (3 subdivisions) and terminal segment (2 subdivisions). The occurrence of the initial, middle and terminal segments corresponds quite closely to the anatomical differentiation of the epididymis into a head, body and tail. The initial segment epithelium in the tammar is lower and has shorter and more slender stereocilia than in other mammals which have been described. Otherwise, the structure of the epithelium has similar characteristics in the tammar to that described in other mammals. Spermatozoa begin to develop the capacity for motility within the initial segment, but only show structural signs of maturation in the middle segment. The sperm head rotates through 90 degrees in the proximal subdivision of the middle segment. The cytoplasmic droplet is detached and spermatozoa develop the capacity for motility in the middle subdivision of the middle segment. The cytoplasmic droplets are phagocytosed by the epididymal epithelium of the middle segment. Sperm storage appears to be the main function of the terminal segment.
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  • 75
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    Keywords: Peptidergic neurotransmission ; Lymnaea stagnalis ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Three neuronal systems of the pond snail Lymnaea stagnalis were immunocytochemically investigated at the ultrastructural level with the unlabeled peroxidase-antiperoxidase technique. Preliminary electrophysiological and cell-filling investigations have shown that a cluster of neurons which reacts positively with an antiserum against the molluscan cardio-active peptide FMRFamide, sends axons to the penis retractor muscle. In this muscle anti-FMRF-amide (aFM) positive axons form neuro-muscular synapses with (smooth) muscle fibers. The morphological observations suggest the aFM immunoreactive system to be involved in peptidergic neurotransmission. In the right parietal ganglion a large neuron (LYAC) is penetrated by aFM positive axons which form synapse-like structures (SLS) with the LYAC. The assumption that the SLS represent the morphological basis for peptidergic transmission is sustained by the observation that iontophoretical application of synthetic FMRFamide depolarizes the LYAC. The axons of a group of pedal anti-vasopressin (aVP) positive cells run in close vicinity to the cerebral ovulation (neuro-)-hormone producing cell system (CDC system) Synapses or SLS between the two systems were not observed. The fact that (bath) application of arg-vasopressin induces bursting in the CDC, may indicate that the vasopressin-like substance of the aVP cells is released non-synaptically.
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  • 76
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    Keywords: Photoperiods ; Pituitary gland, pars tuberalis ; Ultrastructure ; Phodopus sungorus
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    Notes: Summary Conspicuous cytological differences are found between specific secretory cells of the hypophysial pars tuberalis of Djungarian hamsters exposed to long and short photoperiods. The cells differ with respect to the shapes of perikarya and nuclei and show diverse amounts of secretory granules, lysosome-like bodies and glycogen.
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  • 77
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    Keywords: Pituitary gland, pars anterior (distalis) ; Gonadotrops ; Thyrotrops ; Ultrastructure ; Immunolabeling ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Pituitaries of the African catfish (Clarias lazera) were studied with immunocytochemical methods, at the light-microscopic and ultrastructural levels, for the characterization and localization of gonadotropic and thyrotropic cells. Two immunostaining procedures with the use of different markers were carried out: (i) with peroxidase-antiperoxidase, (ii) with protein A-gold. In routinely stained sections for light microscopy two types of basophils were identified in the proximal pars distalis: (1) large, round, purple cells, and (2) small, angular, light-blue cells. Both types were immunolabeled with antibodies against Clarias α,β-gonadotropin (GTH) and salmon G100-GTH. Only the large basophils were immunolabeled with anti-carp β-GTH, whereas the small basophils were the only cells immunolabeled with anti-human thyrotropin beta subunit (anti-h TSH-β). It was concluded that the large basophils represent the gonadotrops and the small basophils the thyrotrops. At the ultrastructural level the immunostaining of the GTH-cells was confined to three types of inclusions: (i) secretory vesicles, (ii) globules, and (iii) electron-dense, membrane-bound irregular masses. Especially the protein A- gold method, in combination with the use of a highly diluted homologous antiserum, resulted in a distinct localization of GTH. The presence of two types of nerve fibres, synaptically contacting the gonadotrops, is discussed with regard to the presence of a peptidergic (stimulatory) and an aminergic (inhibitory) control of GTH-secretion.
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    Cell & tissue research 238 (1984), S. 497-502 
    ISSN: 1432-0878
    Keywords: D2 glycoprotein ; Adrenal gland ; Immunocytochemistry ; Ultrastructure ; Cell adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of the glycoprotein D2 in rat adrenal gland was investigated using immunohistochemical methods, and D2 localization in cultures of adult bovine chromaffin cells was studied by immunofluorescence. D2 was found to be situated on nerve fibers passing through the adrenal cortex and in the medulla zone, and also on the surface of all chromaffin cells. In addition, it was strongly expressed on the surface of glial (Schwann) cells. Cortical cells were unreactive to the antiserum. In cultures, all adrenalin and noradrenalin [dopamine-β-hydroxylase (DBH)-positive] cells were surface labelled for D2. A less frequent second cell type was recognized in vitro which was DBH negative but D2 positive. Such cells were presumed to be Schwann cells. These data are discussed in terms of the developmental origin of the cells and with regard to the putative functional rôle of D2 in cell adhesion phenomena.
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  • 79
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    Keywords: Lymphocytes ; Phytohemagglutinin stimulation ; Nucleolar organizer region ; Three-dimensional reconstruction ; Ultrastructure ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in the spatial organization of nucleolar DNA in lymphocytes during phytohemagglutinin (PHA) stimulation was studied in guinea pigs by means of oxidized diaminobenzidine (DAB) at low pH as a differentially contrasting stain for nucleic acids and by the use of reconstruction of serial sections. The extended DNA filaments situated inside the fibrillar area originate from a large aggregation of heterochromatin, which is closely associated with the nucleolus, and from the perinucleolar shell of condensed chromatin. It is suggested that these two distinct regions of chromatin might be associated with different functions.
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    Cell & tissue research 235 (1984), S. 177-186 
    ISSN: 1432-0878
    Keywords: Retinal pigment epithelium ; Myeloid bodies ; Diurnal variation ; Morphometrics ; Ultrastructure ; Lipid metabolism ; Endoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myeloid bodies (MBs) occur in the newt (Notophthalmus viridescens) retinal pigment epithelium (RPE) and are similar to areas of specialized endoplasmic reticulum found in a variety of other cell types. The function of these structures is unknown, although a role in lipid metabolism has been strongly suggested. Random samples from conventionally-fixed and sectioned newt RPE, obtained over a 24-hr cycle (LD 12∶12), were examined by electron microscopy. Myeloid bodies appear as stacks of flattened endoplasmic reticulum-associated saccules which increase in length and number as the RPE accumulates shed outer segment material, prior to increase in the amount of stored lipid. Associations of MBs with the nuclear envelope can be related to this increased length. Myeloid bodies decrease numerically in the cell as phagosomes are removed from the cytoplasm, but a decrease in mean sectional MB area, seen in the light phase, is counteracted in darkness where individual MBs are larger than those found in the light. The total sectional area of MBs within a cell and their mean length varied depending on the lighting condition; differences were also found between eyes after extended periods of continuous light and dark. Ribosomes were found in association with the surfaces of both flattened and circular MBs, but they were consistently more densely associated with the shorter concave surfaces of curved regions. A new hypothesis for MB function is presented, which is concerned with their role in isolating toxic lipids such as retinoids, which are accumulated during phagocytosis of shed outer segment tips, and which are capable of disrupting membrane-bound systems necessary for their eventual metabolism and safe storage.
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    Cell & tissue research 235 (1984), S. 691-693 
    ISSN: 1432-0878
    Keywords: Plasma cells ; Ultrastructure ; Immunology ; Myxinoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hagfishes, the most primitive vertebrates, are of special interest for the evolution of immune responses. Eptatretus stoutii, the Pacific hagfish, is able to mount cellular and humoral immune responses but all attempts to demonstrate in them the presence of plasma cells have failed. In the present study we demonstrate for the first time plasma cells identifiable by ultrastructural criteria in the pronephros, a primitive lymphohaemopoietic organ, of Myxine glutinosa, the Atlantic hagfish.
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  • 82
    ISSN: 1432-0878
    Keywords: Granular endoplasmic reticulum ; Ultrastructure ; Pinealocyte ; Mole
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    Notes: Summary Ten or more straight tubules, each of which consists of a double unit membrane of granular endoplasmic reticulum with a cylindrical profile, are joined side by side in a raft-like configuration in the cytoplasm of the pinealocytes of Japanese moles. They measure about 60 nm and 100 nm in their inner and outer diameters, respectively, and are often partially connected to unspecialized granular endoplasmic reticulum. Cisterns held between the inner and outer unit membranes with cylindrical profiles vary from 15 nm to 30 nm in width. Ensheathed portions of the cytoplasm are contiguous with cytoplasm outside the tubular units. The inner unit membranes of the tubules bear fewer ribosomal particles than the outer ones.
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    Cell & tissue research 236 (1984), S. 431-438 
    ISSN: 1432-0878
    Keywords: Satellite cells ; Satellite fibres ; Tail muscle ; Urodela ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incidence and ultrastructure of satellite cells in the tail muscles of urodelan larvae were examined during development during which the number of satellite cells is gradually reduced. They are found more frequently in red than in the white fibres in all four stages examined (stage 53, 64, 66+ and juvenile). As development proceeds, intercellular space between satellite cell and muscle fibre is in general gradually extended and is mostly filled with basal lamina. Small muscle cells, satellite fibres, which are situated under the basal lamina of the parent fibre, are morphologically similar to satellite cells but contain a small amount of myofibrils. Three types of satellite fibres are distinguishable on the basis of differences in K2-EDTA-treated ATPase activity, width of Z line, and parent fibre type. Neuromuscular junctions are visible in satellite fibres.
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    Cell & tissue research 236 (1984), S. 465-470 
    ISSN: 1432-0878
    Keywords: Tendon ; Collagen fibrils ; Morphometry ; Ultrastructure ; Loading ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study was designed to gain more detailed morphological information on skeletal tendons in the course of adaptation to physical loading. The effect on collagen fibrils was investigated in 6-week-old mice by means of electron microscopy. Physical loading was performed on a treadmill 5 days a week for 1, 3, 5, 7 and 10 weeks. Morphometric analysis of collagen fibrils revealed the mean diameter, the diameter distribution, the number and the cross-sectional area. The principal observations included: 1. After one week of physical loading an increase in mean fibril diameter (30%, p≦0.01), in number (15%, p≦ 0.05), and in cross-sectional area (15%, p≦0.05), as well as a change in mean fibril diameter distribution. 2. From the third to the seventh week a fall under the level of the controls in mean diameter (26%, p≦0.01), in number (26%, p≦0.01), and a reduced cross-sectional area (17%, p≦0.01), accompanied by signs of splitting of individual collagen fibrils. 3. In the long-term study an increase in fibril number (29%, p≦0.01), a fall in mean diameter from 189 nm in the controls to 179 nm (p≦0.05) but no statistically significant change in the relative cross-sectional area (32%) per unit in comparison to unloaded tendons. The possible physiological implications of the findings are discussed in the light of several regulatory mechanisms known to appear during the course of physical loading in connective tissues.
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  • 85
    ISSN: 1432-0878
    Keywords: Steroids ; Vitellogenesis ; Metabolism ; Ultrastructure ; Teleosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Estradiol injections increase serum level of calcium, amino acid, glucose, protein, ammonia and creatinine in immature Epinephelus akaara, and also increase levels of total lipid, cholesterol, phospholipid and esterified fatty acids. Hepatic protein, glycogen and lipid concentrations also rise after estradiol treatment, and some hepatic enzymes participating in the metabolism of nitrogen, lipid and carbohydrate, show increased activity. Serum vitellogenin levels are increased. Testosterone treatment increases serum protein, total lipid, cholesterol, amino acid and ammonia levels, and also hepatic glycogen content, but in contrast to estradiol treatment, testosterone does not change serum vitellogenin, glucose, calcium, phospholipid, esterified fatty acid and creatinine levels, nor the hepatic lipid and protein content. A small number of hepatic enzymes shows an increased activity. Vitellogenic fish show biochemical changes similar to that of estradiol-treated fish, but are different from those of immature fish. Estradiol treatment induces ultrastructural changes in the hepatocytes of immature fish that are similar to those found in vitellogenic fish. These include a proliferation of rough endoplasmic reticulum and Golgi apparatus, and an increase in glycogen and lipid, all indicative of enhanced metabolic activity.
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    Cell & tissue research 236 (1984), S. 677-683 
    ISSN: 1432-0878
    Keywords: Interneuron ; Synaptology ; Ultrastructure ; Horseradish peroxidase ; Helix pomatia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology, axonal arborization and ultrastructure of synaptic connections of the V21 giant neuron in the visceral ganglion of the snail Helix pomatia has been investigated following intracellular labelling with horseradish peroxidase. The V21 neuron establishes several afferent and efferent axo-axonic connections, mainly along the first half of the primary axon. Collaterals of 200–300 μm length originate from the primary axon, which shows further arborization, and both afferent and efferent synaptic contacts are formed on these fine axon profiles. Afferent and efferent contacts of the cell occur within very short distances of a few micrometers. On the basis of ultrastructure and vesicle and granule content, several afferent terminals can be distinguished on V21 labelled axon profiles. The majority of these afferent terminals resembles peptidergic-(neurosecretory)-like terminals. This finding supports the possible transmitter role of neuropeptides in the central nervous system of gastropods. Our results are consistent with and provide morphological evidence for recent electrophysiological observations suggesting that, in addition to integrating input, the V21 neuron functions as an interneuron in Helix central nervous system.
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  • 87
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    Cell & tissue research 237 (1984), S. 357-362 
    ISSN: 1432-0878
    Keywords: Leydig-Sertoli cell interaction ; FSH stimulation ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Interactions between Leydig and Sertoli cells, as well as a stimulatory effect of FSH on Leydig cell activity, have been reported in many studies. In order to investigate these interactions, the ultrastructure of immature pig Leydig cells under different culture conditions has been studied. When cultured alone in a chemically defined medium, there is a marked regression of the Leydig cell smooth endoplasmic reticulum and a swelling of the mitochondria. Addition of FSH or hCG does not prevent these phenomena. Co-culturing of Leydig cells with Sertoli cells from the same animal maintains the smooth endoplasmic reticulum at the level seen in vivo and in freshly isolated Leydig cells. The addition of FSH to the co-culture stimulates its development and increases Leydig cell activity, as assessed by an increase in hCG binding sites and an increased steroidogenic response to hCG. These results suggest that Sertoli cells exert a trophic effect on Leydig cells, and that the stimulatory effect of FSH on Leydig cell function is mediated via the Sertoli cells. These results reinforce the concept of a local regulatory control of Leydig cell steroidogenesis.
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  • 88
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    Cell & tissue research 238 (1984), S. 221-230 
    ISSN: 1432-0878
    Keywords: Fiber type ; Ultrastructure ; Stereology ; Stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When fast-twitch skeletal muscles of the adult rabbit are subjected to continuous low-frequency activity by electrical stimulation of the corresponding motor nerves, the fibers undergo an ultrastructural transformation, so that after 6 weeks they have acquired an appearance typical of slow-twitch fibers. In the present study, stimulation was discontinued at this stage in order to follow the reverse transformation, in which the fibers recovered their original morphological characteristics under conditions of normal endogenous activity. Stereological techniques were used to assess the time course of this process over a period of 20 weeks in terms of fiber cross-sectional area, extent of T-system, thickness of the Z-band, and volume fraction of mitochondria in the fiber core. Fibers of transformed muscles were smaller than those of control muscles, but the differences were no longer evident after 9 weeks of recovery. After 2 weeks the T-system was still of limited extent, as is characteristic of slow-twitch fibers; it increased toward the amount typical of fast-twitch fibers between 2 and 4 weeks, and had reached its full extent by 12 weeks. The wide Z-bands characteristic of slow-twitch fibers were retained for 4 weeks, but the thickness had begun to decrease by 8 weeks and recovery was complete by 12 weeks. The mitochondrial volume did not increase during recovery, in contrast to the large increases which had been observed to take place between 2 and 6 weeks during the fast-to-slow transformation. Overall, the recovery of fast-twitch ultrastructural characteristics was complete, but followed a more extended time course, and involved less myofibrillar disruption at an intermediate stage, than the original fast-to-slow transformation.
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  • 89
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Autoradiography ; Oocytes ; Nucleolus-like bodies ; Teleost
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytoplasmic granulo-fibrillar masses, usually termed nucleolus-like bodies (NLB) or nuages, have been described in several different cell types. They are sometimes associated with a mitochondrial arrangement, this association often being marked during certain phases of the oocyte cycle. In Xiphophorus helleri, NLB consist of fibrillar and granular material that gradually becomes more granular during meiotic prophase I, and is associated with mitochondrial arrangements during diplotene and dictyate of meiosis. Autoradiographic studies of uridine incorporation into the nucleolus and subsequently into NLB suggest that the latter represent a reserve of ribonucleoproteins that is later used in ribosomal maturation during vitellogenesis.
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  • 90
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    Cell & tissue research 238 (1984), S. 271-288 
    ISSN: 1432-0878
    Keywords: Compound eye ; Ultrastructure ; Grass shrimp, Palaemonetes pugio ; Light adaptation ; Dark adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cone cells and corneagenous cells possess extensive networks of smooth tubular endoplasmic reticulum that may be involved in optical reflectance and light-adaptational responses, respectively. The extracellular basal lamina of the basement membrane is confluent with glial cell capillary walls and may prove to be a viaduct for the transmission of hemolymph-borne substances to the retina or of retinal degradation products to the hemolymph. In addition to dense pigment granules, the distal pigment cells are shown for the first time to contain migratory reflecting platelets that are usually polymorphic in light-adapted eyes but are rectangular in dark-adapted eyes. In the latter these plates become aligned against the crystalline cones and presumably contribute to the reflection superposition optics of the grass shrimp. Dark-adapted retinular cells possess well-developed perirhabdomal cisternae, oblong or ovoid mitochondria, generally vesicular rough endoplasmic reticulum, and occasional, spherical, calcium-like intrarhabdomal inclusions. Light-adapted retinular cells possess poorly developed perirhabdomal cisternae, lamelliform rough endoplasmic reticulum, and condensed mitochondria frequently associated with lipid droplets and pigment granules. The cytoplasmic boundaries of the reflecting pigment cells expand into the extracellular spaces between individual ommatidial retinular cells during dark adaptation and recede to the interommatidial extracellular spaces during light adaptation. Cytoplasmic microfilament bundles found only at the bases of partially light-adapted rhabdomeric microvilli may be involved in microvillar shortening.
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  • 91
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    Cell & tissue research 235 (1984), S. 295-301 
    ISSN: 1432-0878
    Keywords: Tfm/Y mouse ; Submandibular gland ; Sexual ; dimorphism ; Androgens ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the submandibular gland of the mouse with testicular feminization (Tfm/Y) was studied by light and electron microscopy. The architecture of the Tfm/Y gland proved to be rather similar to that of the normal female mouse in both tubular ratio and structure. Granular convoluted tubular cells in Tfm/Y mice characteristically had fewer secretory granules and increased cytoplasmic vacuoles than normal littermates, suggesting an altered synthesis of secretory granules in this cell type of the Tfm/Y mouse. Moreover, there were differences in the ultrastructure of submandibular glands between Tfm/Y and normal female mice. In the gland of the Tfm/Y mouse, basal striations of the striated secretory tubular cells were not so developed and granular intercalated duct cells were less than those of normal females. These findings support the evidence that the secretory tubule of the mouse submandibular gland responds to androgens, resulting in accentuated development in the male, while also suggesting the possibility that the mouse submandibular gland is regulated by other factors which lead to the prominent sexual dimorphism observed in this gland.
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  • 92
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    Cell & tissue research 235 (1984), S. 463-466 
    ISSN: 1432-0878
    Keywords: Endocytosis ; Kidney (rat) ; Proximal tubule ; Apical vacuoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Following perfusion fixation of the rat kidney with glutaraldehyde the proximal tubule cells display small apical vacuoles, large apical vacuoles, and apical vacuoles in which a part of the limiting membrane is invaginated into the vacuole. These invaginated apical vacuoles occur more frequently in proximal convoluted tubules than in proximal straight tubules. One tubular cell may contain apical vacuoles of different sizes and stages of invagination, ranging from larger vacuoles with a wide lumen and a small area of invaginated membrane to smaller elements with no apparent lumen and a large area of invaginated membrane. Invaginated apical vacuoles lie either singly in the cytoplasm or close to the membranes of other apical vacuoles, but never in contact with the cell membrane or the membranes of lysosomes, endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes. These findings suggest that the invaginated apical vacuoles are not fixation artifacts, but rather develop in living state in cells of the proximal tubule from spherical endocytotic elements.
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  • 93
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    Cell & tissue research 236 (1984), S. 339-343 
    ISSN: 1432-0878
    Keywords: Moulting ; Mechanosensory hair ; Chordotonal organ ; Ultrastructure ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of hair mechanoreceptors in crayfish during moulting was investigated with special attention to the interface apparatus between cuticular hairs and sensory cells: the chorda. The chordae are lost with old exuviae at every moulting. They are drawn out from a moulting canal at the tip of the new hair. The chordae are regenerated from a material secreted by sheath cells after moulting. Therefore, the chorda is an inward projection of the cuticular exoskeleton, and it has direct contact with the sensory element, the scolopidium. The scolopidium has been found in both hair mechanoreceptors and subcuticular chordotonal organs in crustaceans, and is thought to be a primitive type of mechano-sensory transducing element. The present observation gives additional evidence for the homology of two sensory elements in arthropods, i.e., the cuticular hair sensilla and subcuticular chordotonal organs.
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  • 94
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    Cell & tissue research 236 (1984), S. 87-97 
    ISSN: 1432-0878
    Keywords: Iodination ; Membrane shedding ; Peroxidase ; Thyroid follicle cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Clusters of luminal dense bodies, limited by a triple-layered membrane, were found in all follicle lumina in thyroid glands of mice. After thyroxine treatment the number of luminal dense bodies increased, especially in the periphery of the lumen, where the intraluminal bodies often displayed a striking resemblance to microvilli. In hyperplastic goiters, obtained by feeding mice with propylthiouracil, luminal dense bodies were replaced by intraluminal vesicles. During goiter involution the vesicles were gradually replaced by luminal dense bodies; the presence of intermediate forms suggests that vesicles and dense bodies are basically the same formations. Luminal dense bodies were observed in colloid droplets indicating their removal by endocytosis. As demonstrated by electron-microscopic cytochemistry, luminal dense bodies contain a membranebound peroxidase, and electron-microscopic autoradiography after administration of 125I indicate that they possess an iodinating capacity. Our observations on mouse thyroid glands suggest that the luminal dense bodies, which appear as vesicles in hyperplastic glands, are formed by shedding of the apical plasma membrane of the follicle cell. The shedding process might be of importance for the turnover of plasma-membrane material.
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  • 95
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    Cell & tissue research 236 (1984), S. 171-180 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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  • 96
    ISSN: 1432-0878
    Keywords: Peripolar cells ; Juxtaglomerular apparatus ; Newborn sheep ; Dexamethasone ; Ultrastructure ; Cytoplasmic granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the renal juxtaglomerular region of newborn sheep, it was found that glomerular peripolar cells and their granules were very much larger than those found in fetal lambs or adult sheep. Similar peripolar cell hypertrophy was triggered in fetal lambs treated in utero with intraperitoneal injections of dexamethasone. Ultrastructurally, granules of peripolar cells from newborn lambs resembled closely the enlarged zymogen granules described in the pancreas of newborn rats. Such peripolar cell hypertrophy may reflect a functional adaptation of the kidney to immediate postnatal life.
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  • 97
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    Keywords: Development ; Enterocytes ; Fish ; Mitosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The processes of proliferation, cell division and differentiation of intestinal epithelial cells have been studied during development of the fish, Barbus conchonius. On the 3rd day, nearly all cells of the presumptive gut proliferate. Once the intestinal epithelium begins to differentiate, a decreasing percentage of proliferative cells can be found. On the 7th day, when intestinal folds start to develop, the proliferative cells become restricted to the future basal parts of the folds. Ultrastructural examination of 3H-thymidine-labeled cells and mitotic cells of 6-day-old larvae shows that functional enterocytes are proliferative. The same feature is suggested for older fish. Proliferating undifferentiated “dark” cells, characterized by many free ribosomes and a few organelles, are also present in the intestinal epithelium of larval fish; they are considered to be stem cells, mainly for goblet cells. Proliferating goblet cells and enteroendocrine cells were not observed. The latter cell type is scarce and has a long turnover time. A common feature of all these dividing cells is the presence of isolated spherical to cylindrical lamellar structures which may have lost contact with the cell membrane during prophase; they probably regain this contact by fusion with the cell membrane at the end of mitosis.
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  • 98
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    Cell & tissue research 237 (1984), S. 123-129 
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine (rat) ; Ultrastructure ; Morphometry ; Development, ontogenetic ; Zymogen granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic acinar cells of rats obtained at 1,2, 3, 5, 7 and 14 days of age were examined using fine structural and morphometric techniques. From 5 days of age onwards, the acinar cells were analysed twice per day, at 20.00 h and 08.00 h. The present study demonstrates changes in the average volume of the cell, nucleus and cytoplasm, and volume densities of various cytoplasmic organelles during the first two weeks after birth. During early postnatal life, the volume density of rER increases, whereas that of zymogen granules decreases. From 5 days of age onwards, the volume densities of these two organelles differ significantly at 20.00 h and 08.00 h. During the first 2–3 days after birth, inclusion body-like structures appear in the cytoplasm of acinar cells; they contain aggregated zymogen granules and, sometimes, amorphous structures or cytoplasmic organelles. These structures also occur in interstitial cells and cells located in the intercalated region between acinar and ductal epithelial cells. Serum level of α-amylase activity is high at birth, compared with other stages during the first three weeks. Degenerating acinar cells and cell debris can be seen in the acinar and ductal lumina during these stages, a feature suggesting holocrine secretion. Cellular polarity appears to be incomplete during the first two or three days after birth.
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  • 99
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    Cell & tissue research 238 (1984), S. 1-12 
    ISSN: 1432-0878
    Keywords: Lung ; Amphibia ; Ultrastructure ; Smooth muscle ; Extracellular matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lung of the giant salamander, Amphiuma tridactylum, is divided into respiratory alveoli by muscular septa that increase the surface area of the lung as well as provide a mechanism for its almost complete collapse during exhalation. The epithelium of the internal surface is of two types: respiratory, composed of a single layer of pneumocytes overlying anastomosing capillaries, and non-respiratory, composed of ciliated cells and mucus-secreting goblet cells. Non-respiratory epithelium covers the apical edges of the septa, whereas the respiratory epithelium lines the alveoli. The smooth muscle of the septa and walls of the lung was studied in preparations of uninflated and acetylcholine-contracted lung. The muscle cells are ultrastructurally similar to other types of smooth muscle but are surrounded by extraordinary amounts of extracellular matrix, containing collagen and elastic fibers and numerous fine fibrils of unknown composition. Smooth muscle in isolated lung strips contracted in a dose-dependent manner when treated with acetylcholine or methacholine; contraction was blocked by atropine. Responses of lung strips to adrenergic agents were limited; only high doses of adrenalin caused slight relaxation of previously contracted muscle. These observations support the hypothesis that contraction of pulmonary smooth muscle is responsible for the ventilatory efficiency of the lung.
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  • 100
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Secretory granules ; Secretory process ; Ultrastructure ; Natrix maura (Reptilia, Ophidia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two different types of ependymal cells were found in the subcommissural organ (SCO) of Natrix maura. Most secretory cells showed morphological features resembling the general structure and ultrastructure of cells in the SCO of other vertebrates. This report describes a second population of cells lining a portion of the dorsal groove of the SCO. These cells were not selectively stained by chromalum-hematoxylin and, under the electron microscope, they were characterized by scarce surface differentiations, sparse apical cytoplasm and short basal processes. Flat, parallel cisternae of the rough endoplasmic reticulum produced vesicles that appeared to be transported to the well-developed Golgi apparatus. Dense secretory granules about 200 nm in diameter were found in the Golgi region. Similar granules were seen in the vicinity of the apical plasma membrane; some of them opened toward the ventricle. All these characteristics clearly differentiate this cell group from the other secretory cells lining the SCO laterally and ventrally.
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