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  • calcium  (38)
  • hypertension
  • Springer  (61)
  • Cell Press
  • 1985-1989  (61)
  • 1989  (61)
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  • 1985-1989  (61)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Dystrophin and the integrity of the sarcolemma in Duchenne muscular dystrophy (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 175-177 
    Details
    ISSN: 1420-9071
    Keywords: Dystrophin ; calcium ; skeletal muscle ; muscular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It is suggested that in Duchenne muscular dystrophy the absence of dystrophin, which is probably a cytoskeletal protein underlying the sarcolemma, causes changes in stretch-activated cation channels rather than direct mechanical tearing of the surface membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01954866
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  • 2
    Electronic Resource
    Electronic Resource
    Cerebrovascular autoregulation is resistant to calcium channel blockade with nimodipine (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 305-306 
    Details
    ISSN: 1420-9071
    Keywords: Baboon ; 133xenon ; cerebral blood flow ; cerebrovascular resistance ; autoregulation ; nimodipine ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In normal baboons cerebrovascular resistance changed along with blood pressure to maintain blood flow constant. This ‘autoregulation’ was not significantly altered in animals treated with a dose of the calcium channel blocker nimodipine causing selective cerebral vasodilation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951818
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  • 3
    Electronic Resource
    Electronic Resource
    Morphological evidence for calcium storage in the chromatoid body of rat spermatids (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 377-378 
    Details
    ISSN: 1420-9071
    Keywords: Chromatoid body ; spermatids ; calcium ; microtubules ; morphology ; pyroantimonate ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological evidence for probable Ca2+ storage in the vesicular elements of the rat spermatid chromatoid body is documented using the K-pyroantimonate method, combined with EDTA chelation. Some vesicles are related to the microtubules associated with the chromatoid body. A possible involvement of Ca2+ in the intracellular movement and/or structural integrity of the chromatoid body is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01957484
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  • 4
    Electronic Resource
    Electronic Resource
    Involvement of a Ca2+-calmodulin interaction in the yeast-mycelial (Y-M) transition of Candida albicans (1989)
    Springer
    Mycopathologia 108 (1989), S. 47-54 
    Details
    ISSN: 1573-0832
    Keywords: Candida albicans ; dimorphism ; yeast-mycelium transition ; calcium ; calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A yeast-mycelium (Y-M) transition of Candida albicans (3153A) was induced by 1.5 mM CaCl2 · 2H2O in defined liquid medium, pH 7, at 25 °C. Germ tube formation was detected after approximately 8 h and peaks of maximum germination occurred at approximately 20 h in all experimental treatments. Non-toxic concentrations of the calmodulin inhibitor R24571 almost completely suppressed germ tube formation whereas trifluoperazine (TFP) and the Ca2+ ionophore A23187 were only about half as effective. Further Ca2+ addition failed to reverse the inhibitory effect of R24571 and induced only about 10% of the cells inhibited by TFP or A23187 to germinate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00436783
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  • 5
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of ramipril in hypertensive patients with renal insufficiency (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 249-256 
    Details
    ISSN: 1432-1041
    Keywords: ramipril ; renal insufficiency ; hypertension ; pharmacokinetics ; ramiprilat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In an open trial, the pharmacokinetics of ramipril and its active metabolite ramiprilat were studied in 25 hypertensive patients with various degrees of renal insufficiency given 5 mg ramipril p.o. for 14 days. Ramipril was rapidly absorbed and reached a peak concentration after 1–2 h. Cmax was greater in patients with severe renal insufficiency, which might indicate a reduced renal elimination rate, although, the rapid decline of the concentration-time curve for ramipril was almost independent of renal function. The mean initial apparent half-lives on Days 1 and 12, respectively, were 2.8 and 3.4 h (Group I: creatinine clearance 5–15 ml/min), 1.8 and 2.3 h (Group II: creatinine clearance 15–40 ml/min), and 1.9 and 1.9 h (Group III: creatinine clearance 40–80 ml/min). No accumulation was observed after multiple dosing. In contrast, the kinetics of its active acid metabolite ramiprilat was significantly influenced by renal function. The mean times to the peak plasma concentration were 5.7 h in Group I, 4.4 h in Group II and 3.8 h in Group III. The initial decline in plasma ramiprilat was dependent upon renal function; the mean initial apparent half-lives (Days 1 and 12, respectively) were 16.0 and 14.8 h (Group I), 10.1 and 9.5 h (Group II) and 10.6 and 8.0 h (Group III). Mean trough concentrations and absolute accumulation also increased with worsening renal function, and the renal clearance of ramiprilat was significantly correlated with the creatinine clearance. The subsequent long terminal phase at low plasma ramiprilat concentrations represented slow dissociation of the ACE-inhibitor complex. The study indicates that in patients with severe renal insufficiency (creatinine clearance below 30 ml/min) smaller doses of ramipril are required than in patients with normal or borderline renal function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00679779
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  • 6
    Electronic Resource
    Electronic Resource
    Renal and hormonal effects of alpha1-adrenoceptor blockade by bunazosin in essential hypertension (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 575-578 
    Details
    ISSN: 1432-1041
    Keywords: bunazosin ; hypertension ; alpha1-adrenoceptor blocker ; blood pressure ; renal blood flow ; renal function ; renin ; aldosterone ; atrial natriuretic peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The renal and hormonal effects of the α1-adrenoceptor blocker bunazosin were examined in 6 patients with essential hypertension. Oral bunazosin for 4 to 12 weeks significantly decreased mean blood pressure by 10%, increased effective renal blood flow and creatinine clearance by 34% and 37%, respectively, the plasma norepinephrine concentration was elevated by 60%, and the plasma atrial natriuretic peptide level was lowered by 22%. The plasma renin activity and aldosterone concentration were unchanged. Thus, a moderate reduction in blood pressure was produced by bunazosin treatment while maintaining renal perfusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637738
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  • 7
    Electronic Resource
    Electronic Resource
    Haemodynamic effects and pharmacokinetics of felodipine at rest and during exercise in hypertensive patients treated with metoprolol or atenolol (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 459-465 
    Details
    ISSN: 1432-1041
    Keywords: felodipine ; metoprolol ; atenolol ; hypertension ; exercise ; pharmacokinetics ; adverse effects ; hypotensive action
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A study has been performed in thirteen patients with essential hypertension, WHO Class I–II, and a diastolic blood pressure ≥95 mm Hg, on beta-blocker (metoprolol or atenolol) monotherapy, who were also given felodipine 10 mg b.d. for 28 days. The acute and steady state blood pressure response at rest and during exercise, and the pharmacokinetics of felodipine and metoprolol, were examined. Felodipine in combination with the beta-blocker reduced the systolic and diastolic blood pressures acutely and at steady-state. The duration of the effect was longer at steady-state. There was a significant correlation between the plasma concentration of felodipine and the change in blood pressure. The increase in systolic blood pressure during exercise was of the same magnitude before and after felodipine administration. No change in resting supine heart rate was found after the administration of felodipine. There were no significant differences in the pharmacokinetics of felodipine during long-term treatment, except for the trough plasma concentration, which was increased at steady-state, even though cumulation of felodipine and its metabolite did not occur. There was a significant decrease in the maximal plasma concentration and AUC of metoprolol after 28 days of treatment with felodipine, but its elimination half-life was not changed. The adverse reactions reported during this study were those generally seen after dihydropyridines and, except for two patients who were withdrawn after the first study day, the effects were well tolerated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558124
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  • 8
    Electronic Resource
    Electronic Resource
    Enalapril and hydrochlorothiazide in hypertensive Africans (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 229-234 
    Details
    ISSN: 1432-1041
    Keywords: enalapril ; hydrochlorothiazide ; hypertension ; side-effects ; Africans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The antihypertensive efficacy both of angiotensin converting enzyme (ACE) inhibitors and thiazide diuretics has been claimed to be influenced by plasma renin activity, which declines with age and is low in blacks. In a double-blind, placebo-controlled, double-dummy, randomized, parallel-group preliminary study, the antihypertensive efficacy and tolerability of the ACE inhibitor enalapril (20 mg day−1) and hydrochlorothiazide (50 mg day−1) were evaluated and compared for 4 weeks in 20 African patients with essential hypertension. The two groups had similar baseline clinical features and serum Na+ and K+ levels. Hydrochlorothiazide caused a significant and sustained fall in erect blood pressure with a reflex tachycardia. Enalapril exerted only a modest antihypertensive action, but significantly reduced erect heart rate. Direct comparison of hydrochlorothiazide — and enalapril — induced hypotension suggested a greater fall in subjects on the thiazide. The 95% confidence limits for the thiazide-enalapril difference in antihypertensive action at the end of the study was 39.5 to −7.5 mm Hg systolic and 22.0 to −6.6 mm Hg diastolic. The maximal blood pressure fall after hydrochlorothiazide was positively correlated with age (r=0.50;p〈0.05), whilst that of enalapril was inversely related age to (r=−0.57,p〈0.05). The results are compatible with the notion that ACE inhibitor monotherapy may be less effective than thiazide diuretic treatment in African and black patients with essential hypertension. The findings also support the concept that age and racial factors may influence the response to antihypertensive treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558152
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  • 9
    Electronic Resource
    Electronic Resource
    Acute calcium entry blockade inhibits the blood pressure but not the hormonal responses to angiotensin II (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 567-573 
    Details
    ISSN: 1432-1041
    Keywords: isradipine ; hypertension ; blood pressure ; calcium entry blockade ; renin angiotensin system ; aldosterone plasma renin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of acute calcium entry blockade by isradipine (IS) and placebo (P) on the haemodynamic and humoral responses to angiotensin II (A II) have been compared in two groups of 9 patients with essential hypertension. During 4 sequential periods each of 20 min, an i.v. infusion of A II 0, 2, 4 and 8 ng · kg−1 · min−1 was given before (control) and 30 min after the oral administration either of IS or P. After IS, both the blood pressure and the angiotensin II-induced pressor effect were significantly reduced. Isradipine increased the heart rate and this cardio-acceleration was potentiated by A II. In contrast, when A II was infused in the absence of IS, heart rate tended to decrease. IS stimulated plasma renin activity and reduced plasma aldosterone. However, it did not affect either the inhibition of plasma renin activity or the rise in plasma aldosterone in response to A II. In conclusion, acute calcium entry blockade in patients with essential hypertension reduces the pressor response to A II, but not the A II-induced inhibition of renin and increase in plasma aldosterone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637737
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  • 10
    Electronic Resource
    Electronic Resource
    Ambulatory blood pressure monitoring during sustained treatment with conventional and extended-release felodipine in mild-to-moderate hypertension (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 555-557 
    Details
    ISSN: 1432-1041
    Keywords: felodipine ; hypertension ; ambulatory blood pressure monitoring ; slow-release formulation ; side-effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To assess the duration of the antihypertensive effect of the dihydropiridine calcium antagonist felodipine in conventional (C-F) and slow-release (ER-F) formulations, 12 patients with essential hypertension underwent ambulatory blood pressure monitoring (ABPM) at the end of a 2-week treatment period with C-F 5 mg b.d., ER-F 10 mg once daily (o.d.) and placebo. C-F, ER-F and placebo were given in a double-blind 3×3 latin square design 4 times replicated. There was no systematic change in the ABP profile over the three study periods regardless of the treatment. In comparison to placebo, the mean 24-h systolic and diastolic blood pressures showed a significant and similar reduction after both formulations of F. Compared to placebo, C-F and ER-F induced a significant reduction in systolic blood pressure for 15 and 21 h, respectively, and of diastolic blood pressure for 16 and 21 h, respectively. Three patients complained of headache (mild in 2, moderately severe in 1), and two patients of nocturia, with either formulation of F.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00562543
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  • 11
    Electronic Resource
    Electronic Resource
    Effect of nicardipine on insulin secretion, glucose and lipid metabolism in hypertensive, non-insulin dependent diabetics (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 1-4 
    Details
    ISSN: 1432-1041
    Keywords: nicardipine ; insulin ; glucose ; diabetes ; hypertension ; metabolic effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Certain acute and chronic metabolic effects of nicardipine have been studied in 20 patients with non-insulin dependent diabetes (NIDD). An intravenous glucose tolerance test (i.v. GTT, glucose 0.33 g/kg as a bolus) and the corresponding insulin response were assessed at the end of a 4 week placebo period, after the first dose and on administration for 12 weeks of nicardipine 20 mg t.i.d. The glucose and insulin responses to the i.v. GTT, evaluated as incremental AUCs, did not change significantly (glucose 30.5 mg/dl·90 min on placebo, 33.1 mg/dl·90 min acutely and 31.4 mg/dl·90 min on chronic administration of nicardipine; insulin 2.08 µU/ml·90 min on placebo, 1.87 µU/ml·90 min acutely and 1.93 µU/ml·90 min after chronic nicardipine). Glucose removal rate (KG) following the i.v. GTT was 0.73%/min on placebo 0.75%/min on acute administration and 0.8%. min−1 with chronic nicardipine. Active treatment produced a significant reduction of blood pressure (from 187/96 mm Hg on placebo to 166/89 mm Hg acutely and 152/83 mm Hg after 12 weeks of nicardipine treatment). It is concluded that the calcium antagonist nicardipine was an effective antihypertensive drug, and that it did not cause deterioration of metabolic control in hypertensive patients with NIDD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561014
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  • 12
    Electronic Resource
    Electronic Resource
    Is captopril effective in controlling blood pressure when administered once daily? An assessment using 24-h ambulatory blood pressure monitoring (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 11-15 
    Details
    ISSN: 1432-1041
    Keywords: hypertension ; captopril ; once-daily administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twelve patients with essential hypertension receiving captopril monotherapy or captopril in conjunction with a diuretic had their 24-h blood pressure profiles monitored using an automatic, non-invasive ambulatory method. The study examined the efficacy of once a day versus twice a day administration of the ACE inhibitor in controlling blood pressure. Six untreated subjects with borderline hypertension were also studied using the same monitoring equipment and with the same frequency, to act as controls because of the possibility of repeated use of the device causing a ‘familiarisation’ effect. The results obtained indicated that if anything, the once daily dosing produced marginally better blood pressure values. The amplitude of the diurnal blood pressure variation was reduced on a ‘second-wearing’ of the monitoring equipment suggesting some degree of familiarisation with the apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561016
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  • 13
    Electronic Resource
    Electronic Resource
    Effect of carteolol on renal function in healthy subjects and patients with hypertension (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 83-86 
    Details
    ISSN: 1432-1041
    Keywords: carteolol ; hypertension ; chronic renal failure ; renal function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of short- and long-term administration of carteolol on renal function has been examined in healthy subjects and in hypertensive patients with or without renal failure. In healthy subjects neither a single dose of 10 mg carteolol nor continuous administration of 20 mg/day for 7 days had any effect on creatinine clearance and renal blood flow. In all subjects the clearance rate of carteolol was about 400 ml/min and its fractional excretion of carteolol exceeded 300%, suggesting that the drug is secreted actively from renal tubules. Twenty-three hypertensive patients with or without renal dysfunction were given carteolol 10 to 20 mg/day for more than 50 weeks in addition to their standard antihypertensive regimens, which were left changed. Laboratory results were compared with the mean values of 50 weeks before and after the addition of carteolol, and none, including plasma creatinine, blood urea nitrogen and electrolytes, were significantly changed. Neither the estimated glomerular filtration rate nor the effect of the drug on blood pressure changed significantly during this prolonged treatment. It is concluded that carteolol had no effect on renal function in healthy subjects and in hypertensive patients with or without renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00561030
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  • 14
    Electronic Resource
    Electronic Resource
    Cardiovascular regulation and lipoprotein profile during administration of co-dergocrine in essential hypertension (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 119-125 
    Details
    ISSN: 1432-1041
    Keywords: co-dergocrine ; hypertension ; presynaptic dopamine2-receptors ; norepinephrine ; haemodynamic effects ; side-effects ; renin-angiotensin-aldosterone system ; lipoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Co-dergocrine has recently been demonstrated acutely to lower plasma norepinephrine (NE) and blood pressure (BP) in patients with essential hypertension, and similar results have been obtained during chronic administration of co-dergocrine to healthy men. The present study investigated the effect of 3 weeks of treatment with co-dergocrine 4 mg/day on BP, plasma catecholamines, certain other BP-regulating factors and serum lipoproteins in patients with essential hypertension. Compared to placebo conditions, co-dergocrine decreased supine BP and heart rate by −7% and the upright plasma NE level by −24%. Supine plasma NE also fell (−24%). Total cholesterol and the LDL + VLDL-cholesterol lipoprotein fraction were lowered by −6%. No significant change was observed in plasma renin activity, angiotensin II, aldosterone and epinephrine levels, whole blood and plasma volume, exchangeable sodium, and the cardiovascular responsiveness to NE, angiotensin II and isoproterenol. The findings suggest that in patients with essential hypertension, chronic treatment with co-dergocrine may slightly decrease sympathetic outflow and, at least in the short-term, lower the potentially atherogenic serum LDL + VLDL − cholesterol fraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00609182
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  • 15
    Electronic Resource
    Electronic Resource
    Antihypertensive and hypouricaemic effects of nitrendipine in chronic renal failure (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 223-227 
    Details
    ISSN: 1432-1041
    Keywords: nitrendipine ; renal failure ; hypertension ; uric acid excretion ; metabolic effects ; cardiovascular risk factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary To evaluate the potential therapeutic value of calcium antagonists in hypertension associated with impaired renal function, blood pressure (BP), certain regulatory factors, and metabolic correlates of cardiovascular risk have been assessed in 15 patients with mild to marked chronic renal failure before and after 6 weeks of therapy with nitrendipine. Compared to placebo, nitrendipine (mean final dose 55 mg/day) decreased supine BP from 173/102 to 146/81 mm Hg and upright BP from 170/105 to 145/86 mm Hg. Heart rate, body weight (+0.8 kg) and exchangeable sodium (+176 mmol, not significant) were minimally increased, and plasma and whole blood volume, plasma angiotensin II and creatinine concentrations, and urinary electrolyte and creatinine excretion were not significantly changed. Nitrendipine increased uric acid excretion and lowered plasma uric acid by 24%; glucose, insulin, serum total lipids, and lipoprotein fractions were unchanged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558151
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  • 16
    Electronic Resource
    Electronic Resource
    Responses of glomerular filtration, renal blood flow and salt-water handling to acute cardioselective and non-selective β-adrenoceptor blockade in essential hypertension (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 343-345 
    Details
    ISSN: 1432-1041
    Keywords: metoprolol ; pindolol ; renal haemodynamics ; salt-water handling ; hypertension ; beta-adrenoceptor blockade ; ISA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects on renal hemodynamics and salt-water handling of equipotent doses of the cardioselective β-blocker metoprolol (M, 100 mg) and of the non-selective (intrinsic sympathetic activity) β-antagonist pindolol (P, 10 mg) were compared in 30 WHO Grade 1–2 hypertensive men. M lowered pulse rate more than P. Systolic pressure was equally reduced by both agents, and diastolic and mean pressures were decreased only after P. Glomerular filtration rate was not significantly altered by either antagonist, and renal blood flow decreased by approximately 11% both after M and P. Renal vascular resistance was unchanged after P, and was increased by 10% after M. It is concluded that, like the effects on central haemodynamics, ISA is more important in the renal response to β-adrenoceptor blockade than is β-receptor selectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558292
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  • 17
    Electronic Resource
    Electronic Resource
    Long-term effect of pindolol on lipids and lipoproteins in men with newly diagnosed hypertension (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 347-350 
    Details
    ISSN: 1432-1041
    Keywords: pindolol ; hypertension ; hyperlipidaemia ; chronic treatment ; cholesterol ; HDL ; LDL ; triglycerides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary This is the first long-term study of pindolol in a population-based sample of men with newly diagnosed hypertension. Eighty-two patients, with a diastolic pressure of 100 mm Hg or more, were identified after screening 6000 men. Many patients were overweight. 82 population controls, matched by sex, age and body mass index, were also recruited. Fourty-eight per cent of the patients and 25% of the controls had a family history of hypertension. Serum triglyceride and urate values were higher in patients than controls at the baseline investigation. Seventy-four patients were followed for 1 year. The dose of pindolol averaged 7.7 mg once daily after 1 year. The diastolic blood pressure was reduced by 13.4 mm Hg. The target pressure of 95 mm Hg or less was achieved in 89% of the patients. The HDL-cholesterol concentration was normal and did not change, whereas the LDL-cholesterol concentration decreased by 0.15 mmol · l−1 during treatment. The total triglyceride values increased transiently up to 6 months, but no significant increase was seen after one year. It is concluded that pindolol had no adverse effect on serum cholesterol and its HDL- and LDL-fractions during 1 year of treatment.
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    URL: http://dx.doi.org/10.1007/BF00558293
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  • 18
    Electronic Resource
    Electronic Resource
    Antihypertensive effect of slow-release nicardipine. A placebo-controlled cross-over study (1989)
    Springer
    European journal of clinical pharmacology 36 (1989), S. 439-442 
    Details
    ISSN: 1432-1041
    Keywords: calcium antagonists ; nicardipine ; hypertension ; placebo effect ; slow-release preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The magnitude and duration of the anti-hypertensive effect of slow-release nicardipine (SR-Nicardipine) have been compared with placebo in 36 uncomplicated essential hypertensives (diastolic BP 95 to 115 mm Hg after 1-month placebo washout). According to a double-blind, randomized, cross-over design they received SR-Nicardipine 40 mg b.d. and placebo for 1 month. At the end of each treatment period, blood pressure and heart rate were measured 12 h after the evening dose and 1, 2, 3 and 4 h after the morning dose. SR-Nicardipine significantly reduced systolic (SBP) and diastolic (DBP) blood pressure at each time after dosing. The absolute decrements peaked 4 h after dosing (−18.3 and −11.7 mm Hg, respectively) and more than 90% of the peak effect persisted 12 h after dosing, both for SBP and DBP. The heart rate was slightly increased by SR-Nicardipine. Adverse effects monitored with a check-list occurred in 31% of patients during SR-Nicardipine treatment and in 28% on placebo. Thus, SR-Nicardipine 40 mg b.d. has a maintained and significant antihypertensive effect lasting up to 12 h in essential hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558066
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  • 19
    Electronic Resource
    Electronic Resource
    Dependent oedema and attenuation of postural vasoconstriction associated with nifedipine therapy for hypertension in diabetic patients (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 333-335 
    Details
    ISSN: 1432-1041
    Keywords: diabetes mellitus ; nifedipine ; hypertension ; oedema ; vasodilator ; blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary We studied the incidence of oedema 2 weeks following initation of nifedipine therapy for hypertension in a group of 10 diabetic subjects, and also measured skin blood flow (SBF) with a laser Doppler flowmeter, before and after lowering the foot. SBF with the foot horizontal increased after nifedipine from 0.31V (arbitrary units of flow) to 0.51V (NS). The postural fall in blood flow in dependency was significantly attenuated by nifedipine from 64.4 to 24.0%. Five patients developed ankle oedema. Results were similar in a small group of non-diabetic subjects starting nifedipine. The attenuation of reflex postural vasoconstriction is therefore likely to contribute to development of the oedema associated with starting nifedipine therapy, which should be monitored carefully in diabetic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558495
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  • 20
    Electronic Resource
    Electronic Resource
    Comparative haemodynamic effects of ketanserin and ritanserin in the proximal and distal upper limb circulations of hypertensive patients (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 215-220 
    Details
    ISSN: 1432-1041
    Keywords: ketanserin ; ritanserin ; hypertension ; haemodynamics ; alpha1-adrenoceptor blockade
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of ketanserin (40 mg p.o.) on blood pressure and brachial haemodynamics (brachial artery diameter, brachial blood velocity and blood flow) have been compared in a double-blind study with those of ritanserin (10 mg p.o.) and placebo. Haemodynamic parameters were measured before and 1 h after treatment. Patients with mild to moderate essential hypertension participated in this study, 6 each on ketanserin, ritanserin and placebo. Placebo significantly reduced heart rate and did not modify the other parameters. Compared to placebo, ketanserin significantly reduced systolic and diastolic blood pressure, increased brachial blood velocity and flow, and decreased forearm vascular resistance. Compared to placebo, ritanserin slightly decreased blood pressure and slightly increased blood flow, but neither effect was significant. When blood circulation to the hand was excluded, neither ketanserin nor ritanserin modified the proximal arterial resistance or blood flow. It is concluded that the actions of ketanserin and ritanserin essentially occurred in the distal part of the upper limb, and alpha1-receptor blockade is probably involved.
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    URL: http://dx.doi.org/10.1007/BF00679772
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    The effect of nisoldipine on renal function in the long-term treatment of hypertension in patients with and without renal impairment (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 437-441 
    Details
    ISSN: 1432-1041
    Keywords: nisoldipine ; hypertension ; renal function/-impairment ; calcium antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of nisoldipine on renal function after 6 weeks treatment was investigated in hypertensive patients with and without renal impairment. Nisoldipine was well tolerated and an effective antihypertensive agent when administered over a period of 6 weeks. There were no significant changes in glomerular filtration, cardiac output, plasma renin activity or serum biochemistry during nisoldipine administration. Effective renal plasma flow was unaffected by treatment in the patients with normal renal function, but in the patients with renal insufficiency, the value decreased by a mean of 12%. Nisoldipine had no major untoward effects on renal function after 6 weeks administration, but minor changes in renal haemodynamics in the patients with renal insufficiency would suggest that careful monitoring of renal function is indicated in such patients.
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    URL: http://dx.doi.org/10.1007/BF00558120
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    Once daily nisoldipine in hypertension: cuff and ambulatory intra-arterial blood pressure (1989)
    Springer
    European journal of clinical pharmacology 37 (1989), S. 551-554 
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    ISSN: 1432-1041
    Keywords: nisoldipine ; hypertension ; ambulatory monitoring ; cuff blood pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Cuff blood pressure data has suggested that the calcium channel antagonist nisoldipine has full twenty four hour efficacy. To test this, 24 h ambulatory intra-arterial blood pressure monitoring was performed on 18 untreated hypertensive subjects (12 men, 6 women) (cuff blood pressure 〉150/95 mm Hg) before and after chronic treatment with 10–20 mg oral nisoldipine taken daily at 08.00 h. Twelve patients completed the study, six being withdrawn, four because of side-effects. After baseline intra-arterial monitoring patients were started on 10 mg nisoldipine daily. Response was assessed by cuff pressures taken 24 h after dosing at fortnightly intervals, and if not controlled (〈150/95 or at least 10 mm Hg reduction in diastolic BP) the dose was increased to 20 mg. All patients received at least six weeks' therapy before the second intra-arterial blood pressure monitoring. There was a slight but insignificant reduction in mean daytime heart rate of 3 beats·min−1. Mean significant reduction in daytime systolic and diastolic BP was 19 mm Hg and 13 mm Hg respectively but there was no significant mean night-time reduction. By comparison 8 out of 12 patients were apparently controlled more than 24 h post dose according to cuff pressures. This study suggests that this formulation of nisoldipine does not control blood pressure over a full 24-h period, and emphasises the importance of 24 h ambulatory monitoring in assessing the efficacy of once-daily antihypertensive agents.
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    URL: http://dx.doi.org/10.1007/BF00562542
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    Calcium movements during each heart beat (1989)
    Springer
    Molecular and cellular biochemistry 89 (1989), S. 103-108 
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    ISSN: 1573-4919
    Keywords: heart ; relaxation ; calcium ; sodium-calcium exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Transsarcolemmal calcium movements are closely related to force generation in the heart. It is important to understand the transport pathways that control these movements of calcium across the sarcolemmal membrane. In the normal, beating heart, sodium-calcium exchange appears to be an important mechanism for the extrusion of calcium from the cell. The kinetics of this exchange are dependent upon the characteristics of the cell action potential. Calcium efflux via sodium-calcium exchange may be sufficient to balance calcium entry through calcium channels during the action potential.
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    URL: http://dx.doi.org/10.1007/BF00220760
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    Sodium-calcium exchange in mammalian heart: current-voltage relation and intracellular calcium concentration (1989)
    Springer
    Molecular and cellular biochemistry 89 (1989), S. 97-102 
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    ISSN: 1573-4919
    Keywords: calcium ; sodium ; fura-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Membrane currents and changes in intracellular calcium ion concentration ([Ca2+]i) have been recorded that can be attributed to the operation of an electrogenic, voltage-dependent sodium-calcium (Na-Ca) exchanger in mammalian heart cells. Single guinea-pig ventricular myocytes under voltage clamp were perfused internally with the fluorescent Ca2+-indicator, fura-2, and changes in [Ca2+]i and membrane current that resulted from Na-Ca exchange were isolated through the use of various organic channel blockers (verapamil, TTX), impermeant ions (Cs+, Ni2+), and inhibitors of sarcoplasmic reticulum (ryanodine). The I-V relation of Na-Ca exchange was obtained from the Ni2+-sensitive current elicited by ramp repolarization from +90 mV to −80 mV. Ramps were sufficiently rapid that little change in [Ca2+]i occured during the ramp. The (constant) [Ca2+]i during the ramp was varied over the range 100 nM to 1000 nM by varying the amplitude and duration of a pre-pulse to the ramp. The reversal potential of the Ni2+-sensitive ramp current varied linearly with 1n([Ca2+])i. The I-V relations at different [Ca2+]i over the range −60 mV to +140 mV were in reasonable accord with the predictions of a simple, simultaneous scheme of Na-Ca exchange, on the basis that only [Ca2+]i had changed. The relationship between [Ca2+]i and current at a constant membrane voltage was also in accord with this scheme. We suggest that Ca2+-fluxes through the exchanger during the cardiac action potential can be understood quantitatively by considering the binding of Ca2+ to the exchanger during the [Ca2+]i-transient and the effects of membrane voltage on the exchanger.
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    URL: http://dx.doi.org/10.1007/BF00220759
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    Appraisal of the physiological relevance of two hypotheses for the mechanism of calcium release from the mammalian cardiac sarcoplasmic reticulum: calcium-induced release versus charge-coupled release (1989)
    Springer
    Molecular and cellular biochemistry 89 (1989), S. 135-140 
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    ISSN: 1573-4919
    Keywords: calcium ; heart ; sarcoplasmic reticulum ; excitation-contraction coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies correlating the calcium current with, respectively, the clamp-imposed voltage and the calcium current in intact isolated mammalian cardiac myocytes are reviewed. The major findings are the following: [1] With the exception of one group, all investigators agree that a calcium transient is never observed in the absence of a calcium current. In addition, there is a good correlation between voltage dependence of the calcium current and that of the calcium transient, although this correlation may vary among the cardiac tissues from different animal species. [2] Repolarization clamp pulses from highly positive potentials produce a ‘tail current’ which is associated with a ‘tail calcium transient’. [3] The calcium transient is inhibited when the calcium current is blocked by calcium deprivation or substitution, or by the addition of calcium current antagonists, despite the fact that sarcoplasmic reticulum still contains calcium that can be released by caffeine (with inhibition of this release by ryanodine). These three findings are strongly in favor of a calcium-induced release of calcium and against the hypothesis of charge-movement-coupled release of calcium from the sarcoplasmic reticulum. [4] The only finding that would be more in favor of the latter hypothesis (although till reconciliable with the former) is that repolarization occurring before the rapid rise of calcium transient is complete curtails the calcium transient. Thus, the possibility that charge movement might somehow regulate calcium-induced release of calcium cannot be excluded.
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    URL: http://dx.doi.org/10.1007/BF00220765
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    The effect of acidosis on excitation-contraction coupling in isolated ferret heart muscle (1989)
    Springer
    Molecular and cellular biochemistry 89 (1989), S. 169-173 
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    ISSN: 1573-4919
    Keywords: pH ; calcium ; heart muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The contractile response to acidosis is the final product of a number of different changes in the excitation-contraction coupling pathway: (i) Cai increases and subsequently decreases during acidosis; (ii) the action potential becomes longer; (iii) the sensitivity of the contractile proteins to Ca2+ decreases. The increase of Cai and the lengthening of the action potential may help to maintain contractile function, although this advantage may be offset if spontaneous Ca2− release from the s.r. occurs, secondary to the increase of Cai. The recovery of force shown in figure 1 occurs at a time when the calcium transient is decreasing, and therefore represents an increasing sensitivity of the contractile proteins to Cai, probably due to a recovery of intracellular pH(6), although it is also possible that a disappearance of spontaneous Ca2+ releases from the s.r. may be contributing [2].
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    Membrane transport and disease (1989)
    Springer
    Molecular and cellular biochemistry 91 (1989), S. 3-11 
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    ISSN: 1573-4919
    Keywords: calcium ATPase ; glucose transport ; herpes virus ; hypertension ; leaks ; pore-formation ; sodium channels ; stress ; toxins ; transport ; viruses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Four situations in which membrane transport is altered by disease are discussed: (a) non-specific leaks induced by poreforming agents; (b) glucose transport and cellular stress; (c) Ca+-ATPase and hypertension; (d) Na− channels and HSV infection.
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    URL: http://dx.doi.org/10.1007/BF00228073
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    The contribution of mitochondrial calcium ion exchange to relaxation of tension in cardiac muscle (1989)
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    Molecular and cellular biochemistry 89 (1989), S. 127-133 
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    ISSN: 1573-4919
    Keywords: mitochondria ; sarcoplasmic reticulum ; calcium ; myocytes ; caffeine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The possible contribution of mitochondrial Ca2+ accumulation and release to contractile phenomena has been investigated. Two intracellular fractions of Ca2+ sequestration can be identified in cardiac myocytes, one ascribed to mitochondria. Two modes of Ca2+ transport exist within the mitochondrial fraction, one dependent upon mitochondrial respiration and the other upon extramitochondrial [Na+]. Experiments with trabeculae show that under appropriate conditions, the rate of relaxation and the amount of tension developed is dependent on these two modes of Ca2+ transport. A model is presented quantifying the contribution of the mitochondria to relaxation.
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    The control of calcium influx by cytoplasmic calcium in mammalian heart muscle (1989)
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    Molecular and cellular biochemistry 89 (1989), S. 109-113 
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    ISSN: 1573-4919
    Keywords: heart muscle ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The role of Ca2+ in the initiation and maintenance of contraction has been extensively studies. Many of these studies have focused on how Ca2+ influx and efflux affect cytoplasmic Ca2+ (Cai) and, therefore, contraction in cardiac muscle. However, it has recently become apparent that Cai itself may play a major role in the control of Ca2+ influx and efflux from cardiac muscle. Here we review current ideas on the mechanisms underlying Ca2+ homeostasis in cardiac muscle, with specific attention to how Cai may control Ca2+ influx, both under normal and pathological conditions.
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    Redistribution of subcellular calcium in rat liver on administration of vanadate (1989)
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    Molecular and cellular biochemistry 90 (1989), S. 155-164 
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    ISSN: 1573-4919
    Keywords: polyvanadate ; mitochondria ; calcium ; pyruvate dehydrogenase ; receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Mitochondria isolated from the livers of rats administered with sodium meta-, ortho-, or polyvanadate, but not vanadyl sulphate, exhibited enhanced Ca2+ — stimulated respiration and uptake of calcium. These effects were shown also by mitochondria isolated from livers perfused with polyvanadate. The concentration of acid-soluble calcium decreased significantly in the mitochondrial fraction on vanadate treatment, while that in the cytosol showed a corresponding increase. Phenoxybenzamine, an antagonist to a-adrenergic receptors, effectively inhibited vanadate-induced Ca2+ mobilization, but surgical sympathectomy was without effect. This is the first demonstration of vanadate mimicking α-adrenergic agonists in vivo.
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    URL: http://dx.doi.org/10.1007/BF00221215
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    ATP inhibits onset of exocytosis in permeabilised mast cells (1989)
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    Bioscience reports 9 (1989), S. 99-109 
    Details
    ISSN: 1573-4935
    Keywords: mast cells ; exocytosis ; G-protein ; GE ; calcium ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract ATP is not required for exocytosis from permeabilised mast cells, and therefore there is no direct role for protein phosphorylation in the late stages of the activation pathway. We have measured the timecourse of exocytosis from permeabilised cells triggered to release hexosaminidase following addition of Ca2+ to cells equilibrated for 2 min with GTP-γ-S. If ATP is included at the time of permeabilisation, then exocytosis commences after a delay, the duration of which depends on the square root of the product [Ca2+][GTP-γ-S], and which may extend to beyond 3 min. When ATP is excluded then the maximal rate of exocytosis is established within 3 secs of completing the effector combination. These results suggest that the achievement of a new steady-state, induced by Ca2+ and GTP-γ-S, and required for exocytosis is inhibited by ATP. From this we conclude that dephosphorylation of an unknown regulator protein may comprise a step in the exocytotic pathway.
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    A comparison of bradykinin, angiotensin II and muscarinic stimulation of cultured bovine adrenal chromaffin cells (1989)
    Springer
    Bioscience reports 9 (1989), S. 243-252 
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    ISSN: 1573-4935
    Keywords: secretion ; exocytosis ; chromaffin cell ; calcium ; bradykinin ; angiotensin II, muscarinic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Bradykinin, angiotensin II and a mascarnic agonist, acetyl-B-methacholine (methacholine) were all found to elict catecholamine release from cultured bovine adrenal chromaffin cells. Bradykinin was the most potent of these secretagogues and methacholine the weakest, with angiotenin II intermediate in efficacy. All three secretagogues were much less effective than nicotinic stimulation. The three secretagogues all produced a rise in cytoplasmic free calcium concentration ([Ca2+]i), measured with the fluorescent indicator fura2, which was partially independent of external calcium. In the case of bradykinin the full rise in ([Ca2+]i) may involve a component of calcium entry in addition to release of calcium from an internal store. Secretion was also found to be partially independent of external calcium. The different efficacies of the three secretagogues in elicting secretion were correlated with the rise in ([Ca2+]i) produced. The differeing efficacies of the three secretagogues may be due to the extent of release of calcium from an intracellular store which itself is less effective in eliciting secretion than a rise in [Ca2+]i following calcium entry due to nicotine. Bradykinin also stimulates calcium entry, and this may increase the efficacy of the initial rise in [Ca2+]i. Treatment with pertussis toxin resulted in an enhancement of secretion in response to all of the secretagogues.
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    A nonselective cation channel activated by membrane deformation in oocytes of the ascidianBoltenia villosa (1989)
    Springer
    The journal of membrane biology 107 (1989), S. 179-188 
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    ISSN: 1432-1424
    Keywords: stretch-activated channel ; calcium ; oocyte ; development ; patch clamp ; tunicate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Cell-attached patch clamp recordings from unfertilized oocytes of the ascidianBoltenia villosa reveal an ion channel which is activated by mechanical deformation of the membrane. These channels are seen when suction is applied to the patch pipette, but not in the absence of suction or during voltage steps. The estimated density of these stretch-activated channels is about 1.5/μm2, a figure equal to or greater than the density of known voltage-dependent channels in the oocyte. Ion substitution experiments done with combined whole-cell and attached patch recording, so absolute potentials are known, indicate that the channel passes Na+, Ca2+ and K+, but not Cl−. The channel has at least two open and two closed states, with the rate constant that leaves the longer-lived closed state being the primary site of stretch sensitivity. External Ca2+ concentration affects channel kinetics: at low calcium levels, long openings predominate, whereas at high calcium virtually all openings are to the short-lived open state. In multiple channel patches, the response to a step change in suction is highly phasic, with channel open probability decreasing over several hundred milliseconds to a nonzero steady-state level after an initial rapid increase. This channel may play a role in the physiological response of cells of the early embryo to the membrane strains associated with morphogenetic events.
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    URL: http://dx.doi.org/10.1007/BF01871723
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    Role of calcium and calmodulin in the regulation of the rabbit ileal brush-border membrane Na+/H+ antiporter (1989)
    Springer
    The journal of membrane biology 108 (1989), S. 207-215 
    Details
    ISSN: 1432-1424
    Keywords: calcium ; calmodulin ; absorption ; ileum ; brush-border vesicle ; phosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary In rabbit ileum, Ca2+/calmodulin (CaM) appears to be involved in physiologically inhibiting the linked NaCl absorptive process, since inhibitors of Ca2+/CaM stimulate linked Na+ and Cl− absorption. The role of Ca2+/CaM-dependent phosphorylation in regulation of the brush-border Na+/H+ antiporter, which is believed to be part of the neutral linked NaCl absorptive process, was studied using purified brush-border membrane vesicles, which contain both the Na+/H+ antiporter and Ca2+/CaM-dependent protein kinase(s) and its phosphoprotein substrates. Rabbit ileal villus cell brush-border membrane vesicles were prepared by Mg precipitation and depleted of ATP. Using a freezethaw technique, the ATP-depleted vesicles were loaded with Ca2+, CaM, ATP and an ATP-regenerating system consisting of creatine kinase and creatine phosphate. The combination of Ca2+/CaM and ATP inhibited Na+/H+ exchange by 45±13%. This effect was specific since Ca2+/CaM and ATP did not alter diffusive Na+ uptake, Na+-dependent glucose entry, or Na+ or glucose equilibrium volumes. The inhibition of the Na+/H+ exchanger by Ca2+/CaM/ATP was due to an effect on theV max and not on theK m for Na+. In the presence of CaM and ATP, Ca2+ caused a concentration-dependent inhibition of Na+ uptake, with an effect 50% of maximum occurring at 120nm. This Ca2+ concentration dependence was similar to the Ca2+ concentration dependence of Ca2+/CaM-dependent phosphorylation of specific proteins in the vesicles. The Ca2+/CaM/ATP-inhibition of Na+/H+ exchange was reversed by W13, a Ca2+/CaM antagonist, but not by a hydrophobic control, W12, or by H-7, a protein kinase C antagonist. we conclude that Ca2+, acting through CaM, regulates ileal brush-border Na+/H+ exchange, and that this may be involved in the regulation of neutral linked NaCl absorption.
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    Ca2+-activated K+ channels from cultured renal medullary thick ascending limb cells: Effects of pH (1989)
    Springer
    The journal of membrane biology 110 (1989), S. 49-55 
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    ISSN: 1432-1424
    Keywords: loop of Henle ; potassium secretion ; channels ; acid/base balance ; thick ascending limb ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Ca2+-activated K+ channels were studied in cultured medullary thick ascending limb cells (MTAL) using the patch-clamp technique. The purpose was to determine the effect of acidic pH on channel properties in excised patches of apical cell membrane. At pH 7.4, increasing Ca2+ on the intracellular side or applying positive voltages increases channel open probability. Reducing pH to 5.8 on the intracellular face of the channel decreases channel open probability at each voltage and Ca2+ concentration. Channel mean open times display two distributions and mean closed times display three distributions. Increasing Ca2+ or applying depolarizing voltages lengthens each of the mean open times and shortens each of the closed times. Lowering pH to 5.8 decreases the mean open times and increases mean closed times at each Ca2+ and voltage with the greatest effect on the mean closed times. In contrast, both single-channel conductance and channel kinetics are unaffected when pH is reduced to 5.8 on the extracellular face of the membrane. We conclude that protons interfere with Ca2+ binding to the gate of Ca2+-activated K+ channels reducing the probability of channel opening.
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    Ca2+ and cAMP activate K+ channels in the basolateral membrane of crypt cells isolated from rabbit distal colon (1989)
    Springer
    The journal of membrane biology 110 (1989), S. 19-28 
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    ISSN: 1432-1424
    Keywords: colon ; ion transport ; ion channel ; cyclic nucleotides ; calcium ; potassium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Using patch-clamp techniques, we have studied Ca2+-activated K+ channels in the basolateral membrane of freshly isolated epithelial cells from rabbit distal colon. Epithelial cell clusters were obtained from distal colon by gentle mechanical disruption of isolated crypts. Gigaohm seals were obtained on the basolateral surface of the cell clusters. At the resting potential (approximately −45 mV), with NaCl Ringer's bathing the cell, the predominant channels had a conductance of 131±25 pS. Channel activity depended on voltage as depolarization of the membrane increased the open probability. In excised inside-out patches, channels were found to be selective for K+ over Na+. Channel activity correlated directly with bath Ca2+ concentration in the excised patches. Channel currents were blocked by 5mm TEA+ and 1mm Ba2+. In cell-attached patches, after addition of the Ca2+ ionophore A23187, which increases intracellular Ca2+, open probability was markedly increased. Channel activity was also regulated by cAMP as addition of 1mm dibutyryl-cAMP in the bath solution in cell-attached patches increased channel open probability over 20-fold. Channels that had been activated by cAMP were further activated by Ca2+. We conclude that the basolateral membrane of epithelial cells from descending colon contains a class of potassium channels, which are regulated by intracellular Ca2+ and cAMP.
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    c-src Locus determines increased rate of Na+, K+-cotransport and increased calcium content in (SHR×WKY)F2 hybrid erythrocytes (1989)
    Springer
    Bulletin of experimental biology and medicine 108 (1989), S. 1634-1636 
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    ISSN: 1573-8221
    Keywords: c-src locus ; calcium ; Na+, K+-cotransport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1007/BF00839709
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    Hemodynamics in emotional responses and in emotional stress (1989)
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    Neuroscience and behavioral physiology 19 (1989), S. 399-407 
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    ISSN: 1573-899X
    Keywords: hemodynamics ; stress ; hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the article, we present experimental data indicating that negative emotional states evoked by electrical stimulation of the ventromedial hypothalamus or by behavioral conflicts are accompanied by a predominance of vascular responses of a presser character possessing the property of summation. In contrast, positive emotional states during a self-stimulation reaction or when animals attain behavioral results satisfying their major biological demands are accompanied by a predominance of pressor-depressor vascular reactions. In individual animals under conditions of experimental emotional stress in conflicting situations of a prolonged character, pronounced disturbances of cardiac-vascular functions occur. Predominantly pressor vascular reactions arise in response to forced stimulation of the ventromedial hypothalamus in such cases. It is shown that changes in vascular tonus plays a leading role in disturbances of AP regulation during stress of immobilization. The most frequent cause of death in animals under such conditions is a progressive fall of AP due to an abrupt decrease in the total peripheral resistance. The resistance of the cardiac-vascular functions to emotional stress is determined to a significant degree by genetic mechanisms.
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    URL: http://dx.doi.org/10.1007/BF01197872
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    Desensitization of the nicotinic acetylcholine receptor: Molecular mechanisms and effect of modulators (1989)
    Springer
    Cellular and molecular neurobiology 9 (1989), S. 141-178 
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    ISSN: 1573-6830
    Keywords: specific desensitization ; nicotinic acetylcholine receptor ; molecular mechanisms ; affinity transitions ; modulators of desensitization ; noncompetitive blockers ; calcium ; substance P ; thymic hormones ; thymopoietin ; thymopentin ; calcitonin gene-related peptide ; receptor phosphorylation ; receptor methylation ; myasthenia gravis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. Loss of response after prolonged or repeated application of stimulus is generally termed desensitization. A wide variety of phenomena occurring in living organisms falls under this general definition of desensitization. There are two main types of desensitization processes: specific and non-specific. 2. Desensitization of the nicotinic acetylcholine receptor is triggered by prolonged or repeated exposure to agonists and results in inactivation of its ion channel. It is a case of specific desensitization and is an intrinsic molecular property of the receptor. 3. Desensitization of the nicotinic acetylcholine receptor at the neuromuscular junction was first reported by Katz and Thesleff in 1957. Desensitization of the receptor has been demonstrated by rapid kinetic techniques and also by the characteristic “burst kinetics” obtained from single-channel recordings of receptor activity in native as well as in reconstituted membranes. In spite of a number of studies, the detailed molecular mechanism of the nicotinic acetylcholine receptor desensitization is not known with certainty. The progress of desensitization is accompanied by an increase in affinity of the receptor for its agonist. This change in affinity is attributed to a conformational change of the receptor, as detected by spectroscopic and kinetic studies. A four-state general model is consistent with the major experimental observations. 4. Desensitization of the nicotinic acetylcholine receptor can be potentially modulated by exogenous and endogenous substances and by covalent modifications of the receptor structure. Modulators include the noncompetitive blockers, calcium, the thymic hormone peptides (thymopoietin and thymopentin), substanceP, the calcitonin gene-related peptide, and receptor phosphorylation. Phosphorylation is an important posttranslational covalent modification that is correlated with the regulation and desensitization of the receptor through various protein kinases. 5. Although the physiological significance of desensitization of the nicotinic receptor is not yet fully understood, desensitization of receptors probably plays a significant role in the operation of the neuronal networks associated in memory and learning processes. Desensitization of the nicotinic receptor could also possibly be related to the neuromuscular disease, myasthenia gravis.
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    Effects of addition of calcium and magnesium salts on ammonia volatilization during manure decomposition (1989)
    Springer
    Plant and soil 115 (1989), S. 53-58 
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    ISSN: 1573-5036
    Keywords: ammonia volatilization ; calcium ; magnesium ; manure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ammonia volatilization during aerobic decomposition of poultry manure was significantly reduced through additions of calcium and magnesium salts. The percentage reduction in ammonia loss decreased during the 48 day decomposition period from 85–100% in the first 2–3 weeks, to 23–52% at the end of the experiment. The maximum amount of ammonia which was retained (i.e. maximum reduction in ammonia loss) through addition of the chloride salts of Mg2+ or Ca2+ was independent of the type of cation. However, CaCl2 released some of the ammonia initially retained as production of CO2 and NH3 from the manure decreased after 3 weeks of decomposition, whereas both MgCl2 and MgSO4 did not release any of the initially retained ammonia over the 7 week incubation period. Over the entire incubation period MgCl2 therefore retained more ammonia than CaCl2. Magnesium sulphate was considerably less effective in retaining ammonia than either chloride salts.
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    Aluminium and manganese and their relation to calcium in soil solution and needles in three Norway spruce (Picea abies, L. Karst.) stands of Upper Austria (1989)
    Springer
    Plant and soil 114 (1989), S. 257-267 
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    ISSN: 1573-5036
    Keywords: aluminium ; calcium ; manganese ; needles ; soil solution ; spruce ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil solution and needles of three mature spruce stands in Upper Austria were analysed in order to investigate the uptake and possible toxic effects of Mn and Al, as these two elements become highly mobilised in the soil due to increasing acidity. The Ca/Al molar ratio in the soil solution was below 0.2 in the most damaged stand during almost the whole vegetation period. Despite different dynamics, Al reaches almost identical values in all stands at the end of the vegetation period in both 1-year (current) and 2-year-old needles, respectively. Therefore, needle analysis is not a useful tool for estimation of free Al in the soil. Needle contents of other elements could provide a better information for understanding the forest decline. Mn in the needles correlates significantly with Mn concentrations in the soil solution. As soil Mn will be mobilised by acidic input, Mn needle content can increase to very high levels. Manganese distribution, its interaction with calcium, and possible toxic effects are discussed.
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    In situ ion exchange resin bags to estimate forest site quality (1989)
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    Plant and soil 119 (1989), S. 186-190 
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    ISSN: 1573-5036
    Keywords: ammonium ; calcium ; forest soil ; ion exchange resin ; magnesium ; manganese ; nitrate ; phosphorus ; soil analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cation and anion exchange resin bags were placed just under the humus layer at five adjacent forest sample sites with differing site quality classes in order to assess the available nutrient supply. For comparison, humus samples were collected from the same sites. Nutrients were extracted from humus samples by conventional extraction methods and by shaking together with ion exchange resin bags. Ca and Mg corresponded best to differences in site quality class, of all analysed ions in thein situ resin bag eluates. Thein situ resin bag adsorption of NH4−N, Na and Mn also showed a positive correlation with site quality. The adsorption of PO4−P was negatively correlated to site quality class. Inadequate amounts of exchange resin, or leaving resin bagsin situ for too long a time result in the replacement of already adsorbed ions by ions with higher ion exchange constants.
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    Honeylocust (Gleditsia triacanthos L.) root response to aluminium and calcium (1989)
    Springer
    Plant and soil 119 (1989), S. 181-185 
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    ISSN: 1573-5036
    Keywords: aluminium toxicity ; calcium ; honeylocust ; root biomass ; root branching ; soil acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Honeylocust (Gleditsia triancanthos L.) root growth response to varying levels of Al and Ca in soil solutions was examined in two horizons each of two forest soils. With results from all four horizons combined, multiple regression analysis indicated that both Ca and Al were significant (p〈0.01) factors affecting root elongation, branching and biomass production. Over a wide range of Al and Ca concentrations in soil solutions from four different soil horizons, the Ca:Al ratio was a significantly better predictor of honeylocust root response to acid soils than Al or Ca alone.
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    Ca2+ interaction with phospholipid bilayers studied by multifrequency phase fluorometry (1989)
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    Bioscience reports 9 (1989), S. 497-502 
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    ISSN: 1573-4935
    Keywords: calcium ; phosphatidate ; DPH ; phase fluorometry ; distributional analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Calcium interaction with phospholipid membranes containing phosphatidic acid is studied by multifrequency phase fluorometry, using DPH as fluorescent molecule. DPH decay is analysed by a continuous distribution of lifetimes. The results suggest an increase of membrane heterogeneity at low calcium concentrations, without changes in the polarity of the environment surrounding the probe.
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    Calcium absorption in man: Some dosing recommendations (1989)
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    Journal of pharmacokinetics and pharmacodynamics 17 (1989), S. 631-644 
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    ISSN: 1573-8744
    Keywords: calcium ; absorption ; efficiency ; dosing ; regimens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The absorption of calcium involves a saturable (active) and a nonsaturable (passive) component. The work of several investigators indicates that an inverse relationship exists between calcium intake and absorption efficiency. Human calcium absorption data from the literature were analyzed using a model which included both an active and a passive absorption component. Simulations were provided to illustrate the suitability of this model, and another previously reported model, to fit the data and to estimate the absorption efficiency of calcium when using different dosing regimens. Comparisons of the values predicted in this study with some literature values are provided and some assumptions and potential limitations associated with the use of this method are discussed. The division of the daily dose into equal increments taken at equally spaced intervals over the course of the day is recommended as a useful procedure for increasing the absorption efficiency and efficacy of calcium.
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    Effect of deicing chloride salts on ion accumulation in spruce (Picea abies (L.) sp.) (1989)
    Springer
    Plant and soil 113 (1989), S. 3-11 
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    ISSN: 1573-5036
    Keywords: calcium ; chlorine ; ion selectivity ; injury ; Picea ; potassium ; retranslocation ; sodium ; uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Among the inorganic chloride salts, NaCl, CaCl2 and in a minor proportion KCl and MgCl2 are used as deicing agents. Mixturs of these salts were merely applied with respect to their physico-chemical properties, but their effect on roadside vegetation has never been studied so far. From a screening of different salt mixtures on ion accumulation in needles and twigs of spruce tress (Picea abies sp.) it was shown that the presence of a small amount of calcium in the salt treatments had some beneficial effects on ion regulation. In the presence of calcium, sodium accumulation could be reduced. But more straightforward was its effect on the selectivity between sodium and potasium in favour of the latter. Chloride concentrations did not alter very much; their role in the presence of monovalent cations is nevertheless obvious and is discussed. The study also confirms the presence of potassium retranslocation in conifer trees. The ion characteristics are briefly discussed with respect to the ecological effects of chloride salts on tress.
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    Coupling of strontium and calcium cycles in Lake Constance (1989)
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    Hydrobiologia 176-177 (1989), S. 323-329 
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    ISSN: 1573-5117
    Keywords: strontium ; calcium ; coprecipitation ; Lake Constance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The contents of Sr and Ca were measured weekly in Lake Constance in 1986. Epilimnetic concentrations of Ca changed between 1.30 × 10-3 mol l-1 (during homothermy) and 0.9 × 10 -3 mol l-1 (during thermal stratification). The seasonal fluctuations of Ca were correlated with those of Sr (between 4.61 and 5.36 μmol l-1). The epilimnion was permanently oversaturated with respect to calcite but not with respect to SrCO3. Analysis of the settling process by use of sedimentation traps revealed two short episodes of very high authigenic settling fluxes of CaCO3, triggered by phytoplankton diatoms. Seasonal changes of the Ca contents (between 4.1 and 30.7 percent of the dry weight) and of the Sr concentrations (from 12 to 75 × 10-3 percent) in the settling material were closely correlated. This suggests a coprecipitation mechanism with a nearly constant stoichiometry of (atoms Sr/atoms Ca) × 1000 of 0.84. Coprecipitation of Sr or Ca with organic matter was insignificant. In the hypolimnion some Sr and Ca were released from the settling material. These results strongly suggest that the cycle of Sr in Lake Constance is driven predominantly by coprecipitation with calcite. The principal chemical mechanisms leading to coprecipitation are discussed.
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    Contribution of dissolved calcium and magnesium to phytoplanktonic particulate phosphorus concentration at the heads of two river reservoirs (1989)
    Springer
    Hydrobiologia 183 (1989), S. 185-193 
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    ISSN: 1573-5117
    Keywords: reservoir ; phytoplanktonic particulate phosphorus ; regulation ; calcium ; magnesium ; multiple regression analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract At the heads of two river reservoirs, the Ishitegawa Dam and the Nomura Dam Reservoirs in Japan, the concentrations of phytoplanktonic particulate phosphorus (PP) were compared with those of dissolved calcium (Ca) and magnesium (Mg), using multiple regression analyses on the data taken from samples which registered more than 6.0 µg l−1 in chlorophyll a concentration. Of the 27 monthly samples, 16 from the Ishitegawa Reservoir and 17 from the Nomura Reservoir were used. A significant regression line, logPP = k 1F + k 2, was obtained, where k 1 (〉 0) and k 2 were constants and F (named the Ca-Mg index) consisted of log(Ca/Mg) − 0.5 log(ca + Mg) in mol concentration in Ca and Mg, in common with the two reservoirs (r 2 = 0.730 & 0.913).
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    Signals controlling renin release in aglomerular toadfish (1989)
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    Fish physiology and biochemistry 7 (1989), S. 323-329 
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    ISSN: 1573-5168
    Keywords: renin release ; aglomerular teleost ; toadfish ; isoproterenol ; cyclic AMP ; cyclic GMP ; calcium ; calcium channel ; K+ depolarization ; baroreceptor ; calcium channel antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The toadfish,Opsanus tau, lacks renal glomeruli and macula densa, but has high renal renin activity and abundant granulated cells in renal arteries and arterioles. Reduction of blood pressure (BP) or blood volume by hemorrhage or vasodilatory drugs causes renin release, indicating that an intrarenal or extrarenal pressure- or volume-sensitive mechanism exists for controlling renin release in the toadfish. Thus, we examined whether 1) β-adrenergic receptor-mediated activation of renin release, and 2) calcium influx which may underlie the baroreceptor mechanism are involved in the cellular control of renin release. Acute injection of isoproterenol (1 μg/kg, n = 6) decreased BP and increased plasma renin activity (PRA) 4–5 fold in unanesthetized toadfish. Propranolol abolished both effects, but did not decrease basal PRA levels.In vitro superfusion of renal slices with bicarbonate Ringer's solution showed a steady secretion of renin, and addition of 50 mM K+ (K+ methylsulfate replacing NaCl, n = 10) to the superfusate markedly suppressed renin secretion. Nifedipine (10−5 M, n = 8) completely restored the high K+-induced inhibition of renin secretion from renal slices, whereas isoproterenol (10−4 M, n = 6) neither increased basal renin secretion nor restored K+-induced renin suppression. These results suggest that calcium influx may mediate inhibitory messages for renin secretion, while the β-adrenoceptor-mediated activation of granulated cells appears absent in toadfish.
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    Studies on the structure and physiology of salmon teleocalcin (1989)
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    Fish physiology and biochemistry 7 (1989), S. 367-374 
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    ISSN: 1573-5168
    Keywords: teleocalcin ; calcium ; corpuscles of Stannius ; gill function ; prolactin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structure and physiology of salmon teleocalcin, a Ca+2 regulating hormone from the corpuscles of Stannius (CS) is reviewed. Teleocalcin is produced by the PAS+, type 1 cells in the CS. The hormone is a disulfide-linked homodimer, with a unique amino acid sequence and a carbohydrate moiety on residue 29. The teleocalcin monomer has a MW of 30 KD, whereas the pro-form of the monomer is 32 KD. The hormone is positively regulated by Ca+2 and its function is to slow the active transport of Ca+2 across the gill epithelium. In conjunction with prolactin, which stimulates Ca+2 transport, teleocalcin is one of the major factors involved in Ca+2 homeostasis in fish.
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    Effect of pod zone moisture content on reproductive growth in three cultivars of peanut (Arachis hypogaea) (1989)
    Springer
    Plant and soil 116 (1989), S. 111-114 
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    ISSN: 1573-5036
    Keywords: calcium ; moisture ; peanut ; pod zone ; reproductive growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Very little research has been done to investigate the effect of a dry podding zone on reproductive development in peanut plants that are otherwise well hydrated via subsoil moisture extraction. The influence of podding zone moisture content on reproductive development and growth of three peanut cultivars (McCubbin, Gajah and Robut 33-1) was investigated in pots grown in the glasshouse. In two cultivars (McCubbin and Gajah) seed yield was reduced in a dry (air-dry) compared to a wet (field capacity) podding zone. Seed yield of Robut 33-1 was unaffected by podding zone moisture content, indicating that cultivar variation in reproductive performance in response to podding zone moisture may exist.
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    Adsorption ofRhizobium meliloti to alfalfa roots: Dependence on divalent cations and pH (1989)
    Springer
    Plant and soil 117 (1989), S. 67-74 
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    ISSN: 1573-5036
    Keywords: bacterial adsorption ; calcium ; magnesium ; Medicago sativa ; pH ; Rhizobium meliloti ; root surface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Adsorption ofRhizobium meliloti L5-30 in low numbers to alfalfa (Medicago sativa L.) roots was dependent on the presence of divalent cations, and required neutral pH. Adsorption was proportional to Ca and/or Mg concentrations up to 1.5 mM. Ca was not substituted by Sr, Ba or Mn. Adsorption was abolished and viability decreased at pH≤6. When lowering pH, higher Ca concentrations were required to attain similar adsorption levels, indicating a marked interactive effect between Ca and H ions. Pretreatment of the roots with Ca and low pH did not affect subsequent adsorption of the bacteria. However, Ca pretreatment ofR. meliloti sustained further adsorption at low Ca levels and low pH substantially affected their ability to adsorb. Low pH appears to affect the stability of binding causing desorption of the previously bound bacteria. The presence of saturating concentrations of heterologousR. leguminosarum bv.trifolii A118, did not prevent the expression of divalent cations and pH requirements, as well as their interaction. Our results suggest that rhizobial binding to the root surface already shows the Ca and pH dependence of alfalfa nodulation, which was generally associated to some event prior to rhizobial penetration of root hairs.
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    Adenine and pyridine nucleotide levels during calcium-induced conidiation in Penicillium notatum (1989)
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    Antonie van Leeuwenhoek 56 (1989), S. 191-199 
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    ISSN: 1572-9699
    Keywords: calcium ; conidiation ; nucleotides ; nucleotide charges ; Penicillium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Concentrations of adenine and pyridine nucleotides and the associated charge values were examined in extracts of mycelium of Penicillium notatum during vegetative growth and reproductive development promoted by the addition of Ca2+ (10 mmol dm-3). The significant increase in adenylate energy charge promoted by Ca2+ was due to a fall in intracellular AMP and a concomitant rise in ATP concentration. Intracellular concentrations of NADH and NAD fell within 1 h of the addition of Ca2+. The catabolic reduction charge was unchanged by Ca2+ whilst the anabolic reduction charge increased in Ca2+-induced mycelium due to lowered intracellular NADP concentration. Reduced concentration of NADPH in Ca2+-induced mycelium, relative to the vegetative controls, lowered the phosphorylated nucleotide fraction. The results are discussed in relation to metabolic economy during morphogenesis in P. notatum.
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    Nutritional disturbances of young pines in a dry heath forest (1989)
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    Plant and soil 113 (1989), S. 229-235 
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    ISSN: 1573-5036
    Keywords: aluminium ; calcium ; foliar analysis ; magnesium ; nitrogen ; nutritional disturbance ; Pinus sylvestris L. ; potassium ; soil analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tree decline has been observed recently in 25–30 year old pine stands inCladina andCalluna-type heath forests in the Hämeenkangas and Pohjankangas areas of southwestern Finland. The trees had grown more or less normally for 15 years. During the following 7 to 8 years increased growth occurred. From 1982 to 1984, however, the trees revealed a sudden reduction in height increment. Additionally, some trees were marked by poor apical shoot dominance. Occasionally complete crown dieback was observed. The trees retained only one to three years' needles. These needles often were characterized by a brownish yellow discoloration. Chemical foliar and soil analysis indicate both a nitrogen deficiency and a deficiency in calcium and magnesium related to the relatively high aluminium levels in the soil. In the needles of affected trees phosphorus and especially potassium concentrations were higher than normally. The low content of nitrogen, calcium and magnesium in the soil is related to the acidic, nutrient-poor bedrock, and the low cation exchange capacity. Also the leaching of nutrients, the shallow and poor quality of the humus layer, and the removal of nutrients by tree harvesting may have effected on the nutritional disturbances.
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    Effect of deicing NaCl and CaCl2 on spruce (Picea abies (L.) sp.) (1989)
    Springer
    Plant and soil 120 (1989), S. 203-211 
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    ISSN: 1573-5036
    Keywords: calcium ; chlorine ; climate ; injury ; Picea ; rating ; sodium ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract NaCl and CaCl2 are frequently used as deicing agents during the winter season. The present study compares the effect of these deicing salts on salt injury on spruce trees (Picea abies sp.). From two field experiments carried out for ten weeks during the winter period of 1986–1987, and a total dose of 1.5 kg m−2 NaCl, CaCl2 or a 75/25 NaCl/CaCl2 mixture, it was found that the presence of calcium clearly reduced the salt injury as was indicated by salt tolerance ratings. These ratings corresponded well to the Cl− concentrations found in needles and twigs. Though an equal dose of Cl− was given, in the presence of CaCl2 the uptake of Cl− was inhibited. Surely the role of calcium on ion permeability in salinized soil should have its effect, together with the regulatory role that calcium has on ion accumulation and transport. Furthermore it was found that the climatic conditions and the calcium status of the soil only have an effect on the time of appearance of the injury.
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    The Role of Calcium Ions and Bile Salts on the Pancreatic Lipase-Catalyzed Hydrolysis of Triglyceride Emulsions Stabilized with Lecithin (1989)
    Springer
    Pharmaceutical research 6 (1989), S. 449-457 
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    ISSN: 1573-904X
    Keywords: pancreatic lipase ; lipase ; lipolysis ; triglycerides ; kinetics ; mechanism ; calcium ; bile salts ; lecithin ; emulsions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Lecithin-stabilized triglyceride emulsions are subject to hydrolysis by pancreatic lipase. The time profiles of these reactions are characterized by a lag-phase and a zero-order phase. Lag phases are more pronounced with long-chain triglycerides. Ca2+ is effective in reducing the lag-phase and activating lipase. Kinetic analysis of the reactions suggests that, like previous findings by others, taurodeoxycholate (TDC) micellar solutions combine with the lipase–colipase complex to form another catalytically active enzyme form. This enzyme form exhibits reduced activity in the absence of Ca2+. In the presence of Ca2+ the mixed micelle–lipase complex becomes more active and opens a new pathway for lipolysis. It is suggested that this enzyme form can bind more easily to interfaces with different physicochemical properties. Under these conditions, Ca2+ activates the lipolysis of short-, medium-, and long-chain triglycerides by a similar mechanism. Maximum activities were measured in the presence of approximately 6 mM TDC and 30 mM Ca2+. The experimental conditions approximate the physiological conditions in the gastrointestinal tract since all of the factors studied here have been reported to be necessary for in vivo lipolysis and/or absorption of triglycerides. A mechanistic model for lipolysis in the presence of Ca2+ and the bile salt TDC is proposed which accounts for most of the experimental observations in a quantitative manner.
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    Platelet Na+/H+ exchange in spontaneously hypertensive rats (1989)
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    Bulletin of experimental biology and medicine 107 (1989), S. 200-202 
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    ISSN: 1573-8221
    Keywords: hypertension ; platelets ; sodium-proton exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Autoradiographic study of human epidermocytes cultured in a low calcium medium (1989)
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    Bulletin of experimental biology and medicine 107 (1989), S. 574-577 
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    ISSN: 1573-8221
    Keywords: epidermocytes ; calcium ; multiplication ; autoradiographic investigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Permeability of erythrocyte membranes for monovalent cations (Na+, K+) and their transformation in essential symptomatic (renal) hypertension (1989)
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    Bulletin of experimental biology and medicine 107 (1989), S. 632-635 
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    ISSN: 1573-8221
    Keywords: hypertension ; erythrocyte membrane permeability ; electron microscopy ; erythrocyte transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Course of wound healing in spontaneously hypertensive rats under the influence of morphine, substance P, and its SP1–4 fragment (1989)
    Springer
    Bulletin of experimental biology and medicine 107 (1989), S. 867-871 
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    ISSN: 1573-8221
    Keywords: wound healing ; morphine ; hypertension ; substance P
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    Electronic Resource
    Electronic Resource
    Cellular mechanisms of transient contraction of coronary arterial smooth muscles in hypoxia: Role of intracellular Ca++ (1989)
    Springer
    Bulletin of experimental biology and medicine 107 (1989), S. 3-6 
    Details
    ISSN: 1573-8221
    Keywords: hypoxia ; coronary spasm ; calcium ; sarcoplasmic reticulum ; inositol-1,4,5-triphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00837042
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