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Biomedical subjects

H Zumkley

Publications and source records attributed to H Zumkley.

At least 37 records · Page 2Linked to original sources

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↗

New aspects concerning the 22sodium influx into red cells in essential hypertension.

The different components of the total 22Na influx into red cells (RC) of 21 normotensive subjects and 38 patients with essential hypertension were measured and correlated together. We found that the acceleration of total net 22Na influx in essential hypertension is predominantly caused by an increase of the Na leak and only in a small part effected by an elevated phloretin-sensitive Na countertransport. The 22Na influx mediated by the anion exchange system and the furosemide inhibitable Na-K cotransport were not significantly altered. The correlations suggest that the total 22Na influx into RC of normotensive subjects is very strong and equally defined by both the Na leak and the anion exchange system, whereas an influence of the Na countertransport is not detectable. On the contrary we found a clear decreased dependence upon the anion exchange system in favour of the countertransport in patients with essential hypertension, while the influence of Na leak was unaltered.

Adult↗

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↗

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↗

Magnesium, potassium and hormonal regulation.

Clinical and experimental data demonstrate that hormonal factors are involved in magnesium regulation. It is possible that the parathyroid hormone could play an important role in the maintenance of normal calcium and magnesium concentrations. The action of other hormones in magnesium metabolism appears to be an indirect response to factors such as calcium concentration or changes in volume. Alterations of the magnesium concentrations are important for the intracellular potassium, sodium and calcium content. Magnesium deficiency appears to lower intracellular potassium and to increase intracellular sodium and calcium concentrations. Therefore, magnesium is essential to avoid cardiovascular diseases (acute myocardial infarction, arrhythmias, hypertension) and to restore cellular potassium concentrations.

Animals↗

Side effects of diuretics.

Diuretics are amongst the most widely used drugs. Fortunately enough, there are rather few clinically relevant side effects. The following side effects are discussed in this paper: disturbances of electrolyte, acid-base- and water balance, metabolic changes (uric-acid, carbohydrate-metabolism, lipid metabolism), unspecific side effects and drug interactions. Finally the prevention of side reactions of diuretics is briefly mentioned.

Calcium↗

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↗

Intracellular Na+ and Ca2+ activities in aortic smooth muscle cells from spontaneously hypertensive rats.

Elevations of intracellular Na+ and Ca2+ in essential hypertension have up to now only been demonstrated in blood cells. Therefore, intracellular Na+ and Ca2+ activities were determined in cultured aortic smooth muscle cells from nine spontaneously hypertensive rats of the Münster strain and from nine normotensive Wistar rats. Intracellular ion activities were determined by ion-selective electrodes. In muscle cells from spontaneously hypertensive rats intracellular Na+ activity was markedly elevated (P less than 0.01), whereas intracellular Ca2+ was not significantly different. This points to the preponderance of genetic causes for the elevation of intracellular Na+, whereas the disturbances in cellular Ca2+ metabolism may additionally require humoral factors to become manifest.

Animals↗

Renal excretion of magnesium and trace elements during cisplatin treatment.

Plasma and urine concentrations of platinum, magnesium, zinc and copper were measured in 15 patients treated with cisplatin. The renal excretion rates of platinum, magnesium, zinc and copper were markedly increased. In plasma markedly elevated levels of platinum could be found and were accompanied by decreased concentrations of magnesium, potassium and calcium. The plasma concentrations of zinc and copper showed only slight changes. Our results indicate, that cisplatin may influence renal excretion of some electrolytes and trace elements by a specific factor and/or by alteration in renal function.

Cisplatin↗

Zinc concentrations in plasma and erythrocytes in digitalized patients.

Determination of zinc, sodium, potassium and magnesium in plasma and red blood cells were performed in 31 controls and 63 patients treated with digitalis. In digitalized patients sodium and zinc concentrations in red blood cells were significantly increased. The intraerythrocyte magnesium and potassium levels as well as all investigated electrolytes in plasma remained within the normal range. There was a close relationship between the increase of sodium and zinc content in red blood cells, indicating alterations in transmembrane transport mechanisms induced by digitalis therapy.

Digitalis Glycosides↗

[Intracellular sodium and calcium as a genetic marker in essential hypertension].

In 33 normotensive probands with a familial disposition to hypertension and in 18 normotensives without a family history of hypertension, aged 15 to 24 years, intracellular Na+ and Ca2+ activity in red blood cells was determined by ion-selective electrodes. The activities represent the free, i.e. unbound intracellular fraction of each ion. In the group with a family history of hypertension the mean intracellular Na+ activity was 9.74 +/- 1.43 mmol/l and clearly exceeded that in the group without predisposition to hypertension, which was 7.74 +/- 1.06 mmol/l. Even larger differences were found in mean intracellular Ca2+ activity (9.54 +/- 9.56 mumol/l in the group with familial disposition and 1.87 +/- 3.47 mumol/l in the control group). However, due to the relatively wide range of the values, especially with respect to the Ca2+ activities in probands with familial disposition to hypertension, the values from the two groups overlapped. The results suggest that elevation of intracellular Na+ and Ca2+ activity may be evidence for a genetically determined later development of hypertension.

Adolescent↗

Intracellular cation activities and concentrations in spontaneously hypertensive and normotensive rats.

1. The intracellular concentrations of Na+,K+ and Ca2+ were measured in the erythrocytes of spontaneously hypertensive rats and normotensive Wistar rats. 2. The intracellular Na+ concentration in hypertensive rats was slightly elevated at 3.16 +/- 0.25 compared with 2.85 +/- 0.35 mmol/l (P approximately 0.05) and intracellular Na+ activity was markedly increased in hypertensive rats. 3. Intracellular Ca2+ activity was 7519 +/- 28990 nmol/l of free water in hypertensive rats compared with 123 +/- 98 in controls (P less than 0.01). 4. The cytoplasm of hypertensive animals did not buffer Ca2+ as effectively as that of normal animals. 5. It is concluded that a decreased binding capacity of intracellular macromolecules for Na+ and Ca2+ may explain the disturbances of intracellular electrolyte composition in spontaneously hypertensive rats.

Animals↗