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Biomedical subjects

W Zidek

Publications and source records attributed to W Zidek.

At least 289 records · Page 16Linked to original sources
PubMed1984

Intracellular sodium and calcium in vascular smooth muscle of spontaneously hypertensive rats.

Intracellular Na+ and Ca2+ activities in arterial smooth muscle cells and red blood cells from normotensive and spontaneously hypertensive rats were measured by ion-selective electrodes. In red blood cells and aortic smooth muscle cells from spontaneously hypertensive rats examined immediately after isolation, intracellular Na+ and Ca2+ activities were elevated. In aortic smooth muscle cells from spontaneously hypertensive rats, which had been cultured in artificial medium for 10-14 days, intracellular Na+ activity, but not intracellular Ca2+ activity, was elevated. From these observations it is concluded that (a) increased intracellular Na+ activity is associated with a genetic disposition to hypertension, whereas humoral factors are necessary for intracellular Ca2+ activity to be elevated; and (b) the electrolyte abnormalities in red blood cells from spontaneously hypertensive rats reflect concomitant changes in arterial smooth muscle, so that the findings in red blood cells can be regarded as reliable indicators of a generalized defect in cellular electrolyte metabolism.

Animals↗
PubMed1984

Scintigraphic localization of phaeochromocytomas.

131I-meta-iodobenzylguanidine scanning was performed in 14 patients with phaeochromocytomas. In all but one patient scintigraphy successfully localized the lesion(s). The results confirm that scintigraphic imaging with 131I-meta-iodo-benzylguanidine, a noninvasive method, is a valid and reliable procedure for imaging and localization of adrenal and extra-adrenal phaeochromocytomas, both benign and malignant.

3-Iodobenzylguanidine↗
PubMed1984

Intracellular electrolytes and hormonal parameters during weight reduction.

The mechanisms of the blood pressure lowering effect of weight reduction have not yet been fully elucidated. In this study the intracellular electrolyte composition and hormonal parameters were monitored in 12 obese subjects during a 10-day diet with 800 kcal/day. A decrease in intracellular free Na+ (p less than 0.05) and Mg2+ (p less than 0.01) and in total intracellular K+ (p less than 0.05) was observed. Furthermore, plasma aldosterone and renin activity (p less than 0.05) increased, probably due to a moderate simultaneous salt restriction. There was also an increase in plasma PGI2 concentration (p less than 0.05). The observed decrease in intracellular free Na+ may be caused by salt restriction. The decrease in intracellular K+ and free Mg2+ may be induced by hormonal factors, e.g. an altered insulin secretion. Possible causes for the known hemodynamic effects of weight reduction are the diminution of intracellular Na+ and the increase in plasma PGI2.

Adult↗
PubMed1984

Intracellular electrolytes during antihypertensive treatment with a loop diuretic.

The effect of the loop diuretic, piretanide (12 mg/day on blood pressure and intracellular electrolyte composition in red blood cells during a six-week treatment period was studied in 14 previously untreated essential hypertensive patients. Blood pressure fell continuously during the six weeks, intracellular Na+ activity in red blood cells increased slightly (P less than 0.05), and there was a marked decrease in intracellular Ca2+ activity (P less than 0.01). Intracellular K+ concentration was not altered. It is concluded therefore, that intracellular free Na+ does not correlate with the actual blood pressure, whereas the fall in blood pressure is associated with a decrease in intracellular free Ca2+, suggesting that intracellular free Ca2+ is involved in the regulation of vascular tone.

Adult↗
PubMed1984

Diagnosis and treatment of phaeochromocytoma with 131I-metaiodobenzylguanidine.

131I-meta-iodobenzylguanidine scintigraphy was performed in 30 patients with biochemically proven catecholamine excess. In all but two patients scintigraphy localised the lesion(s) correctly. In high concentrations the same radiopharmaceutical agent was used for treatment of 3 patients with a malignant multilocular and one patient with an intra-adrenal unilocular phaeochromocytoma. The results confirm that 131I-meta-iodobenzylguanidine is suitable for scintigraphic imaging of intra-adrenal and extra-adrenal phaeochromocytomas, both benign and malignant, as well as for treatment of malignant phaeochromocytoma.

3-Iodobenzylguanidine↗
PubMed1984

Intracellular calcium in essential hypertension. A parameter for assessing effective antihypertensive treatment.

The effects of the loop diuretic piretanide on blood pressure and intra-erythrocytic free Na+ and Ca2+ were examined in 14 essential hypertensives. Intra-erythrocytic Ca2+ activity was found to decrease (P less than 0.01) and Na+ activity to increase (P less than 0.05). In spontaneously hypertensive rats (SHRs) hypovolaemia abolished the humoral transmission of hypertension to normotensive rats. Therefore the decrease in intracellular Ca2+, which may be responsible for the diminished vascular tone under diuretic treatment, could be mediated by a suppression of humoral factors due to diuretic-induced hypovolaemia.

Adult↗
PubMed1984

Role of kidney and adrenals in the humoral pathogenesis of primary hypertension.

In 18 spontaneously hypertensive rats (SHR) of the Münster strain the circulation was connected to that of normotensive animals using the carotid arteries and external jugular veins. The circulations were mixed by a peristaltic pump. In this model the normotensive rats were made hypertensive after a 10-min cross-perfusion cross unidentified humoral factors causing vasoconstriction play an essential role for the development of hypertension in SHRs.

Adrenal Glands↗
PubMed1983

Obesity, hypertension and intracellular electrolytes.

Intracellular activities of sodium and calcium were determined in red cells of patients with obesity. Compared to normal people mean intracellular sodium and calcium were higher in obese patients. However, increased intracellular sodium and calcium could only be observed in those patients with obesity suffering from hypertension or showing a familial disposition to hypertension. In contrast there was no difference in intracellular sodium and calcium between obese normotensives lacking a familial disposition to hypertension and normal people. Thus, our results suggest, that the observed variations in intracellular sodium and calcium in obesity are due to an enhanced blood pressure or a familial disposition to hypertension and not specific for obesity.

Calcium↗
PubMed1983

Intracellular Na+ and Ca2+ in aortic smooth muscle cells after enzymatic isolation in spontaneously hypertensive rats.

In aortic smooth muscle cells from spontaneously hypertensive and normotensive rats, which were separated from the blood vessels by enzymatic digestion, intracellular Na+ and Ca2+ activities were measured. The determinations were made by ion-selective electrodes. In smooth muscle cells from spontaneously hypertensive rats intracellular Na+ and Ca2+ activities were elevated as compared to cells from normotensive rats (P less than 0.001 for Na+ and P less than 0.01 for Ca2+). Since in cultured aortic smooth muscle cells from spontaneously hypertensive rats intracellular Ca2+ is known to be not significantly increased, primarily humoral factors may account for the changes in intracellular Ca2+ reported.

Animals↗
PubMed1983

Potassium load in spontaneously hypertensive rats. Effects on blood pressure, renin-angiotensin, aldosterone, and intracellular electrolytes.

To study the mechanisms by which K+ influences vascular tone in hypertension, spontaneously hypertensive and normotensive rats were examined during an oral K+ load. There was a marked decrease in blood pressure in spontaneously hypertensive but not in normotensive rats. Intraerythrocytic K+ concentration and activity increased in normotensive but not in spontaneously hypertensive rats. Intraerythrocytic Na+ concentration and activity declined in both strains, the decrease in Na+ activity being more prominent in spontaneously hypertensive rats (P less than 0.05). Intraerythrocytic Ca2+ activity decreased in spontaneously hypertensive rats (P less than 0.01) but not in normotensive rats. In both strains plasma aldosterone concentration increased during K+ load, the plasma renin activity being suppressed. The basal levels of plasma aldosterone in spontaneously hypertensive rats exceeded those in normotensive rats. It is concluded that intraerythrocytic Ca2+, and to a lesser extent Na+, correlate best with the blood pressure changes. These ionic changes may be mediated by hormonal factors. The significance of the elevated plasma aldosterone levels has not yet been entirely clarified.

Aldosterone↗
PubMed1983

Sodium and calcium in lymphocytes and erythrocytes in essential hypertension.

The present study compared protein-related sodium concentrations in lymphocytes with the sodium and calcium activities in erythrocytes from 12 untreated patients with essential hypertension and 15 normal control subjects. It appeared that protein-related Na+ in lymphocytes was elevated about threefold in essential hypertensives. Comparable increases were also noted in intracellular Na+ and Ca2+ activities. The correlation between Na+ in lymphocytes and in erythrocytes was not close. These results suggest that the determination of protein-related Na+ in lymphocytes discriminates between normotensives and essential hypertensives as well as measurements of ion activities in erythrocytes. Altered intracellular ion binding may be partly responsible for the changes in intracellular protein-related Na+.

Calcium↗
PubMed1982

[Intracellular electrolytes and serum lipids in relation to dietary fatty acid intake].

In 12 moderately obese female probands without metabolic abnormalities, intracellular Mg++ activity, Na+ activity and Na+ concentration, and serum triglycerides, total cholesterol and HDL cholesterol were measured under a diet with fatty acids varying in the degree of saturation. During the diet with mainly saturated fatty acids the intracellular Na+ activity and concentration fell from 7.34 +/- 2.02 to 6.37 +/- 1.43 (p less than 0.05) and from 5.28 +/- 0.57 to 4.98 +/- 0.80 mmol/l respectively (mean values +/- SD). Intracellular Mg++ activity fell from 1.36 +/- 0.23 to 1.20 +/- 0.17 mmol/l (p less than 0.05). During the subsequent diet consisting of mainly polyunsaturated fatty acids, intracellular Na+ activity and concentration rose to 7.95 +/- 2.81 and 5.17 +/- 0.91 mmol/l respectively (p less than 0.05). The intracellular Mg++ activity showed a further decrease to 1.04 +/- 0.14 mmol/l (p less than 0.01). During the diet consisting of mainly saturated fatty acids there was a significant correlation between the changes in HDL cholesterol and intracellular Na+ activity (r = -0,78; p less than 0.01). The initial values of intracellular Mg++ correlated with HDL cholesterol (r = 0.53; p less than 0.05). Thus, moderate obesity at any rate was not associated with intracellular electrolyte disturbances. The composition of dietary fatty acids affects intracellular electrolyte composition. This may be caused on the one hand by modified membrane function due to the uptake of the various fatty acids into the membrane, and on the other hand by changes in the synthesis of prostaglandins depending on the intake of precursors.

Adult↗
PubMed1982

Intracellular sodium and calcium in essential hypertension.

Intracellular sodium and calcium activities were measured by ion-selective electrodes in red blood cells of primary hypertensives and of normotensives with and without a familial disposition to hypertension. Intraerythrocytic sodium activity was markedly elevated in patients and normotensives with a familial disposition to hypertension (15.16 +/- 2.35 mmol/l in hypertensives and 9.74 +/- 1.43 mmol/l in normotensives, respectively, mean value +/- SD) as compared to the corresponding group without such a history (8.35 +/- 2.08 mmol/l in hypertensives and 7.00 +/- 1.38 mmol/l in normotensives). Mean intraerythrocytic calcium activity showed the highest values in patients with hypertension (32.8 +/- 32.5 mumol/l in patients with and 25.3 +/- 19.0 mumol/l in those without a familial disposition to hypertension), whereas in normotensives mean calcium activity was much lower (9.6 +/- 9.7 and 4.8 +/- 4.5 mumol/l, respectively). Our results document that a disturbed intraerythrocytic sodium metabolism is limited to patients with essential hypertension and a familial disposition to hypertension and, to a lesser extent, to normotensives showing a familial disposition to hypertension. Thus, a genetically determined alteration in intracellular sodium can be assumed. Furthermore, the observation of an enhanced intraerythrocytic calcium in some essential hypertensives with and without a familial disposition suggests additional factors, other than sodium, responsible for the disturbed intracellular calcium balance in these patients.

Adolescent↗
PubMed1982

Plasma fibronectin in man after a severe paraquat intoxication.

Fibronectin is a cell surface glycoprotein and belongs to the opsonic system. It can be easily determined in human plasma by laser nephelometry. Patients in shock or with septicemia have extremely low concentrations of fibronectin in plasma which seems to correlate with a depression of the reticuloendothelial system (RES). Determination of fibronectin in human plasma may be a useful parameter for monitoring RES function. Severe intoxication with Paraquat causes a reduction of fibronectin and possibly influences RES function as well.

Adult↗
PubMed1982

Adrenal scintigraphy in primary aldosteronism. Spironolactone as a cause of incorrect classification between adenoma and hyperplasia.

In primary aldosteronism the type of adrenal lesion was correctly identified in 28 of 40 patients (70%) by standard adrenal scintigraphy. Suppression scintigraphy did not improve the validity of the method. In all patients the diagnosis was confirmed by surgery (unilateral adenoma n = 32; bilateral adrenal hyperplasia n = 11). False classification of the adrenal lesion(s) by standard scintigraphy was mostly due to a bilateral adrenal isotopic uptake in patients with an unilateral aldosteronoma. However, a substantial number of these patients (6 of 11 patients) received long-term spironolactone treatment prior to the examination. Thus, in primary aldosteronism adrenal changes induced by chronic spironolactone administration are probably a major cause for incorrect differentiation between adenoma and hyperplasia by adrenal scintigraphy.

19-Iodocholesterol↗