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Biomedical subjects

W Zidek

Publications and source records attributed to W Zidek.

At least 271 records · Page 15Linked to original sources
PubMed1985

Zinc metabolism during captopril treatment.

In 14 hypertensives the effect of captopril (angiotensin-converting enzyme inhibitor) treatment on red blood cell Na+, K+, Mg2+ and Zn2+ concentrations and on plasma Zn2+ concentrations were studied. Intraerythrocytic Zn2+ concentrations increased slightly, whereas plasma zinc concentrations decreased. The concurrence of hypozincemia with side effects resembling the symptoms of zinc deficiency such as loss of smell and taste suggests a role of alterations in zinc metabolism for the pharmacodynamics of captopril.

Adult↗
PubMed1985

Long-term ECG in pheochromocytoma.

In 13 patients with pheochromocytoma (in all but 2 cases localization by scintigraphy) investigations using Holter long-term ECG were performed under medication with alpha- and beta-sympathicolytic drugs under bed rest conditions. The incidence of ventricular dysrhythmias hardly exceeded the extent of a normal control group. In 1 case alpha-methyltyrosine caused a first to second degree AV block and beyond this a stable high frequency sinus rate without any adaptation to the environmental requests. In 12 patients the frequency profile showed sudden and inadequate rises of heart rate up to 200% of very short duration, reaching their maximum within about 20 s of the onset of muscular activity. Although less pronounced, these characteristics were still found 1-2 weeks after operation. In our opinion the heart rate profiles described reveal a dysfunction of the entire autonomus nervous system in pheochromocytoma.

Adolescent↗
PubMed1985

[Typical spontaneous changes in heart rate in pheochromocytoma].

Investigations in 13 hospitalized patients with pheochromocytomata showed peculiar characteristics of heart rate variation at rest, when compared with normals. All patients were given alpha- and beta-sympatholytic drugs. In one case alpha-methyl-Tyrosine caused I-II degree AV blocks and a stable high frequency sinus rate without physiological variations. Resting heart rate in pheochromocytoma varied interindividually from 55-105/min, in the absence of clinical attacks of the underlying disease. The frequency profile was characterized in 12 patients by sudden and inadequate rises of heart rate (200%) of short duration, which were often recorded within 20 seconds of the onset of muscular activity. A similar but less pronounced heart rate modulation was found 1-2 weeks after operation in 3 cases. Our observations indicate that the heart rate profile described may be a sensitive parameter of dysfunction of the autonomous nervous system in pheochromocytoma. Whether the heart rate characteristics are of diagnostic value has to be assessed by further studies.

Adolescent↗
PubMed1985

Ca2+ analysis in arteries of spontaneously hypertensive rats by proton-induced X-ray emission.

Numerous investigations have shown that Ca2+ plays an important role in the pathogenesis of hypertension. Intracellular Ca2+ measurements have been carried out with Ca(2+)-selective electrodes and the Quin 2 method. The present study used particle induced X-ray emission to investigate the Ca2+ distribution in arterial smooth muscle. This method correlates Ca2+ distribution with the morphological structure of the tissue. The Ca2+ content of the aortas and renal arteries was measured in 22 spontaneously hypertensive and 11 normotensive rats. The findings demonstrate significant Ca(2+)-elevation in the aortas of spontaneously hypertensive rats compared with the aortas of normotensive rats (3124.9 +/- 790.0 versus 2031 +/- 478 micrograms Ca2+/g; P < 0.05), whereas there was only a tendency to Ca2+ elevation in the renal arteries of spontaneously hypertensive rats compared with normotensive rats (3336.0 +/- 1798.0 versus 1533.2 +/- 1082.0 micrograms Ca2+/g; NS). The Ca2+ was mainly detected in the muscle containing tunica media.

Animals↗
PubMed1985

Intracellular sodium and calcium during antihypertensive treatment.

In 49 untreated essential hypertensives the effects of the loop diuretic, piretanide, in a dose of 12 mg daily (n = 14) and of 6 mg daily (n = 18) as well as of beta blockers (pindolol, metipranolol, atenolol, n = 17) on blood pressure, intracellular Ca++ and Na+ activity in red blood cells were examined. Intracellular ion activities were measured by ion-selective electrodes. The higher dose of piretanide caused a decrease of intracellular Ca++ activity and an increase of intracellular Na+ activity. Under the lower dose of piretanide there was a comparable decrease of intracellular Ca++ activity but no significant change of intracellular Na+ activity. Beta blockers decreased intracellular Ca++ activity but left intracellular Na+ activity unchanged. It is concluded that intracellular free Ca++ plays an important role in the regulation of vascular tone in essential hypertension. There seems to be no direct relation between intracellular free Na+ and blood pressure under antihypertensive therapy.

Adrenergic beta-Antagonists↗
PubMed1985

Humoral factors in primary hypertension.

In 56 spontaneously hypertensive rats of the Muenster strain, either parabiosis or cross circulation was performed with normotensive Wistar Kyoto rats. Crossed circulation was made through the common carotid arteries and external jugular veins using a peristaltic pump. In parabiosis and in cross-circulation experiments, hypertension was transmitted from spontaneously hypertensive to normotensive rats. Nephrectomy or adrenalectomy in the spontaneously hypertensive rat before cross circulation abolished this effect. After volume depletion in the hypertensive animals, hypertension was not transmitted either. Furthermore, the effect of plasma fractions from essential hypertensives (n = 20) on blood pressure of normotensive rats was studied. Substances with molecular weights higher than 6000-8000 and lower than 500 were removed from 60-ml plasma by ultrafiltration and dialysis. After chromatography on a Bio-Gel P-4 or P-2 column, three to four fractions were formed according to the results of UV spectrophotometry and concentrated to 0.5 ml. One fraction from hypertensive plasma containing substances with molecular weights between 1000 and 2000 increased blood pressure in the rat by 16.3 +/- 8.2 mmHg within 10 minutes when injected intravenously. The respective fractions from normotensive rat plasma increased blood pressure by 3.6 +/- 2.1 mmHg (p less than 0.01). The results demonstrate a circulating hypertensive factor both in spontaneously hypertensive rats and in essential hypertensives, which may be crucial for the pathogenesis of essential hypertension.

Animals↗
PubMed1985

Evidence for a hypertensive factor in the blood of essential hypertensives.

From plasma of essential hypertensives and normotensives several fractions were obtained after: (1) removing proteins with a relative molecular mass greater than 6,000-8,000, and (2) chromatography on a Biogel P4 or Biogel P2 column. The eluate was separated into 3-4 fractions. These fractions were concentrated to a small volume of 0.5 ml and were injected intravenously in normotensive rats, the mean arterial pressure of which was monitored. One of the fractions from normotensive plasma increased blood pressure in the rat in some but not in all cases. Using the fractions from hypertensive plasma there was an increase in blood pressure in the fraction corresponding to that of normotensive plasma increasing blood pressure and in another fraction of lower molecular weight. Angiotensin II is unlikely to be responsible, since it could be identified in another fraction than that containing the hypertensive factor. It can be concluded that in the blood of essential hypertensives a hypertensive factor is present, which increases blood pressure even in normotensive animals. Its secretion may represent the critical step in the pathogenesis of essential hypertension.

Animals↗
PubMed1985

Essential hypertension versus secondary hypertension: discrimination by intracellular electrolytes.

Intracellular activities of sodium and calcium were determined in red blood cells in a group of 106 patients, consisting of essential and renal hypertensives and of normotensives with and without renal insufficiency. Calcium and sodium activities were elevated in essential hypertensives as compared to hypertensives suffering from renal insufficiency. Compared to normotensives without renal insufficiency higher sodium and calcium activities were measured in normotensives without renal impairment. Thus the results suggest that the determination of intracellular electrolytes might be a useful tool for the distinction of secondary hypertension. Furthermore, as yet unidentified humoral factors produced in the kidney might be involved in the regulation of the blood pressure, as a decrease in production of these hypothetic humoral factors (following the destruction of renal tissue) could be the cause for the changes in electrolyte composition.

Adult↗
PubMed1985

Influence of low and high cadmium diet in normotensive and hypertensive SH-rats.

Normotensive and SH-rats (Münster strain) were fed a cadmium-rich, normal or cadmium-poor diet. The blood pressure was slightly increased in normotensive rats after feeding a cadmium-rich diet and decreased after a cadmium-poor diet. In contrast, in SH-rats blood pressure was decreased after a cadmium-rich and increased after a cadmium-poor diet. This behavior of the blood pressure corresponded with the intra-erythrocytic Ca2+ activities. Whereas the calcium activities increased in the normotensive group after a cadmium-rich diet, the calcium activities decreased in the SH-group after cadmium feeding. It should be pointed out that normally the calcium activities were found to be elevated in SH-rats. Thus, cadmium feeding here had the same effect as a calcium antagonist.

Animals↗
PubMed1985

The evaluation of tissue Ca2+ by proton-induced x-ray emission in the arteries of spontaneously hypertensive and normotensive rats.

Numerous investigations have shown that Ca2+ plays a critical role in the pathogenesis of hypertension. The intracellular Ca2+ measurements were mainly carried out with Ca2+ selective electrodes. In the present study the particle-induced x-ray emission (PIXE) was used for investigating the Ca2+ distribution of arterial smooth muscle of spontaneously hypertensive and normotensive rats. PIXE yields a correlation of the Ca2+ distribution with the morphological structure of the arterial muscle. The Ca2+ content of the aortic wall of six spontaneously hypertensive and four normotensive rats was investigated. The results demonstrate that the tissue Ca2+ measurements found mainly in the smooth muscle containing tunica media of hypertensive rats are much higher (3105 micrograms Ca2+/g tissue +/- 569 micrograms Ca2+/g tissue) than of normotensive rats (2031 micrograms Ca2+/g tissue +/- 478 micrograms Ca2+/g tissue).

Animals↗
PubMed1985

Humoral factors in the pathogenesis of primary hypertension.

In 42 spontaneously hypertensive rats of the Münster strain either parabiosis or cross circulation with normotensive Wistar Kyoto rats was performed. Cross circulation was made through the common carotid arteries and external jugular veins using a peristaltic pump. In parabiosis and in cross circulation experiments hypertension was transmitted from the spontaneously hypertensive rats to normotensive rats. Nephrectomy or adrenalectomy in the spontaneously hypertensive rat before cross circulation abolished this effect. After volume depletion in the hypertensive animals hypertension was not transmitted either. It is concluded that humoral factors causing vasoconstriction play an essential role in the development of hypertension in the spontaneously hypertensive rat.

Adrenal Glands↗
PubMed1984

[Nuclear medical therapy of pheochromocytoma].

131I-metaiodobenzylguanidine (131I-MIBG) is used for localization procedures in patients with phaeochromocytoma. In high doses and concentrations the same radiopharmaceutical agent can be used for treatment of adrenomedullary tumors. In 4 of our patients, treatment with 131I-MIBG improved the clinical symptoms. In 2 patients with a multilocular phaeochromocytoma, a tumor reduction of some 61% after a total dose of 415 mCi, and of about 10% in the second patient after 365 mCi 131I-MIBG, was measured by computed tomography. In a unilocular intra-adrenal phaeochromocytoma treated with 131I-MIBG, initial clinical improvement was followed by an obstruction of the large abdominal vessels by the growing tumor. There was no close correlation between therapeutic effect and catecholamine secretion. No severe side effects were observed. This new nuclear medical treatment appears to be a reliable therapeutic method for malignant phaeochromocytoma.

3-Iodobenzylguanidine↗
PubMed1984

Assessment of magnesium and aluminum in erythrocytes by the laser microprobe mass analyzer (LAMMA).

The erythrocyte magnesium content was determined using two different analytical systems (atomic absorption spectrometry and the laser microprobe mass analyzer) with specimens from 18 patients with normal renal function and from 10 patients with chronic renal insufficiency. There was a good correlation (r = 0.73) between the two analytical systems. Additionally, the laser microprobe mass analyzer was used to determine the aluminum content of plasma and erythrocytes in specimens from patients who ingested moderate quantities of aluminum hydroxide for several months. Results showed a significant elevation of the plasma aluminum concentration, but a normal erythrocyte aluminum content. The laser microprobe mass analyzer may be useful in studies of mineral metabolism in humans.

Adult↗