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Biomedical subjects

H Zumkley

Publications and source records attributed to H Zumkley.

At least 55 records · Page 3Linked to original sources

Intracellular Na+ as a genetic marker of essential hypertension.

In 1960 the pathophysiological mechanisms by which Na+ is involved in human essential hypertension were first elucidated by the finding that intracellular Na+ is elevated in red blood cells of essential hypertensives. Furthermore it was found that (1) transmembranous Na+ fluxes in red blood cells of essential hypertensives are changed in parallel with intracellular Na+ concentration, reflecting the metabolic disturbances better than the Na+ concentration measurements, (2) in normotensives with a familial disposition of essential hypertension intracellular Na+ and transmembranous Na+ fluxes are elevated, (3) uremia affects intracellular Na+ levels similarly as essential hypertension, and (4) intracellular free Na+ and free Ca++ is increased in spontaneously hypertensive rats. It can be assumed that elevated intracellular Na+ plays a causative role in essential hypertension.

Animals↗

[Disturbed sodium and calcium exchange in erythrocytes of spontaneously hypertensive rats (author's transl)].

In red blood cells of spontaneously hypertensive and of normotensive rats intracellular NA+ activity (a(i)Na), Na+ concentration (]Na+]i) and Ca2+ activity (a(i)Ca) were measured by ion-selective electrodes and flame photometry, respectively. In spontaneously hypertensive rats a(i)Na and a(i)Ca were significantly elevated as compared with the normotensive controls, whereas [Na+]i showed no significant difference. In hypertensive animals a(i)Na, exceeded [Na+]i, in normotensive rats a(i)Na was lower than [Naf+]i. From these results it can be concluded: (1) In spontaneously hypertensive rats the transmembraneous distribution of free Na+ is altered, (2) an elevation of intracellular free Ca2+ may contribute to increased vascular contractility in hypertensive animals, (3) the described abnormalities may be caused by a lowered binding-capacity of intracellular macromolecules for Na+ and Ca2+.

Animals↗

[Renin-angiotensin-aldosterone system in essential hypertension. Inappropriately high plasma aldosterone in young patients with severe hypertension and in older hypertensives].

Both in male (n = 353) and in female patients (n = 211) with essential hypertension supine (basal) plasma renin activity showed an age-dependent significant decrease whereas plasma aldosterone remained almost unchanged in women or was even slightly increased with age in men. In younger hypertensives (15-34 years) a significant inverse correlation between plasma renin activity and mean arterial blood pressure could be observed. On the other hand, middle-aged men (35-50 years) showed a positive relationship between renin and blood pressure whereas in females of the same age group no correlation between these two parameters was found. In older patients (greater than 50 years) of both sexes a positive correlation between renin activity and mean arterial blood pressure was obtained. In all age-groups and in both sexes there was either no correlation, or only a weak (positive) one, between plasma aldosterone and mean arterial blood pressure. These findings suggest that in essential hypertension renin secretion is regulated mainly by blood pressure. The observed sex and age-related differences may be due to changes in the renovascular system. The inappropriately high plasma aldosterone concentrations (compared to the relatively low renin levels) in younger hypertensives with severe hypertension, and in the older population, document disturbed aldosterone secretion which probably contributes to the elevated blood pressure in these patients.

Acute Disease↗

Lateralization procedures in primary aldosteronism.

The diagnostic validity of adrenal isotopic scanning, adrenal venous aldosterone, adrenal phlebography and computed abdominal tomography (CT) was studied in 44 patients with primary aldosteronism. In all patients the diagnosis was confirmed by surgery (unilateral adrenal adenoma n = 32, bilateral adrenal hyperplasia n = 12). Both adrenal scintiscan, adrenal venous aldosterone and CT allowed in a comparable high percentage of patients (71%0 the exact classification of the adrenal lesion(s), whereas adrenal phlebography could distinguish adenoma from hyperplasia in 57%. Marked differences between the lateralization procedures, however, were observed in predicting incorrect preoperative indentification: adrenal scintiscan 29%, adrenal venous aldosterone 3%, adrenal veno-graphy 6% and CT 0%. Finally, the percentage of patients in whom no differentiation between the two main subgroups of primary aldosteronism could be obtain varied between 0% with adrenal isotopic scanning and 37% with adrenal phlebography (CT 29% and adrenal venous aldosterone 26%). Both scintiscan and adrenal venous aldosterone were not improved by the administration of dexamethasone. Our findings document that adrenal venous aldosterone determinations, adrenal isotopic scanning and computed tomography are equally valid in differentiating unilateral adenoma from bilateral adrenal hyperplasia in primary aldosteronism. However, adrenal scintiscan is hampered by a relative high percentage of incorrect results independant whether dexamethasone was used or not. Contrary, adrenal venous aldosterone and computed tomography seemed to have no or only a minor risk in assuming an incorrect classification of the adrenal lesion(s).

Adenoma↗

Plasma zinc and magnesium alterations in acute myocardial infarction.

In 31 patients suffering from acute myocardial infarction plasma zinc and magnesium concentrations were measured. In acute infarction plasma zinc concentrations were strikingly decreased and plasma magnesium concentration slightly decreased. A close correlation between fall in zinc concentrations and the rise of serum CPK in these patients could be observed. No correlations were found between infarct localisation and sex and alterations in zinc concentrations. In contrast, a close correlation between fall in zinc content and severity of infarction occurred. Thus, the observed alterations in plasma zinc probably can be used as a diagnostic and prognostic indicator. Furthermore it should be considered whether zinc substitution would be of therapeutical benefit in patients suffering from acute myocardial infarction.

Creatine Kinase↗

Aluminum, zinc and copper concentrations in plasma in chronic renal insufficiency.

Plasma aluminium, zinc and copper were determined in 68 patients with chronic renal insufficiency and in 20 healthy individuals. In the renal insufficiency group 16 patients had received aluminium containing substances particularly phosphate binding drugs (aluminium hydroxide) for a long time. We observed that only the patients taking aluminium hydroxide showed elevated aluminium levels in plasma (controls: 0.86 +/- 0.27 mumoles/l; renal insufficiency: 3.05 +/- 1.63 mumoles/l). In two of these patients with symptoms of "dialysis dementia", plasma aluminium concentrations were markedly increased. The zinc concentrations in plasma of patients with renal insufficiency were slightly decreased (controls: 14.48 +/- 2.65 mumoles/l; renal insufficiency: 11.77 +/- 2.35 mumoles/l); the plasma copper concentrations were slightly increased (controls: 17.3 +/- 2.83 mumoles/l; renal insufficiency: 22.98 +/- 4.7 mumoles/l). There was a distinct decrease of plasma zinc concentrations in patients with raised aluminium levels. The clinical aspects of these changes are discussed.

Aluminum↗

[Enzyme activities of beta-hexosaminidase in urine from patients with renal diseases (author's transl)].

Enzymatic activities of beta-hexosaminidase and beta-galactosidase were determined in 24 h urine specimens from patients with renal diseases, from individuals with essential hypertension and patients with other diseases. Patients suffering from various renal diseases had significantly higher activities of the beta-hexosaminidase than individuals with essential hypertension or other diseases. However for beta-galactosidase only the mean value of the enzymatic activities was elevated. The possible mechanisms causing an increase of these enzymes in 24 h urine samples are discussed.

Galactosidases↗