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Biomedical subjects

D Ben-Ishay

Publications and source records attributed to D Ben-Ishay.

At least 91 records · Page 5Linked to original sources

Experimental hypertension and catecholamine distribution in the rat brain.

Hypertension was induced in rats (Hebrew University strain) by three different procedures: (1) deoxycorticosterone acetate (DOCA)--salt treatment; (2) unilateral renal artery clip or (3) chronic salt-loading. Noradrenaline (NA) and dopamine (DA) distribution in different brain areas was assayed following induction of hypertension. NA content increased significantly in various areas: the increase of NA in the pons-medulla was common to all procedures inducing hypertension. NA content increased also in the mesencephalon, the hypothalamus and the rest of the forebrain (DOCA--salt hypertension), in the mesencephalon, the hypothalamus and the cortex (in renal clip hypertension). No significant changes in DA content were observed in any region of the brain following induction of hypertension by the three different methods. In two substrains, selected from the Hebrew University strain, for their respective sensitivity (H) or immunity (N) to hypertension induced by DOCA--salt treatment, there were no significant increases in NA or DA in any part of the brain following DOCA--salt treatment. Comparison of NA concentrations in these strains showed that NA was significantly higher in the pons-medulla of the untreated N strain rats than in the medulla of untreated H strain or in untreated rats of the original strain (Hebrew University). A model is presented suggesting that central NA-containing neurons plays a major role in controlling hypertension.

Animals↗

Clinical and pathological relevance of erythrocyte cation fluxes measurement in hypertension.

1. The clinical applications of a simple laboratory test for the diagnosis of essential hypertension were further investigated on a large number of patients (124 individuals). 2. The reduced erythrocyte ratio of Na+/K+ net fluxes observed in essential hypertensives might be secondary to a functional defect in a Na+-K+ cotransport system. 3. A similar reduction in the ratio of Na+/K+ net fluxes was also observed in erythrocytes of some normotensive subjects born of hypertensive parents and of genetically hypertensive rats. This suggests that the erythrocyte membrane defect follows the genetic transmission of hypertension.

Animals↗

Effect of co-trimoxazole on normal creatinine clearance.

The effect of co-trimoxazole on creatinine clearance was studied in six individuals with normal kidney function. The mean decrease in creatinine clearance during treatment was 47 ml/min and the mean increase in plasma-creatinine was 0.27 mg/dl (P less than 0.01). Although creatinine clearance decreased by 29%, sodium excretion increased by 22%. Discontinuation of co-trimoxazole resulted in a prompt return of creatinine clearance to pretreatment values, and a consistent antinatriuresis.

Adult↗

Hypertension and brain catecholamine distribution in the Hebrew University Sabra, H and N rats.

1. The concentration of catecholamines was measured in several brain areas of the Hewbrew University Sabra rat (SB rat), and in two substrains selected for their respective sensitivity (H) or immunity (N) to hypertension. 2. Hypertension was induced in SB rats by DOCA-salt, renal artery constriction and NaCl 1.7% drinking. The noradrenaline content was consistently elevated in the medulla oblongata of hypertension animals. In other brain areas the rise in noradrenaline varied in the different types of hypertension. 3. Administration of DOCA-salt to H and N rats, while causing marked hypertension in the former, had no effect on noradrenaline in either strain. 4. Untreated, normotensive N rats had in the medulla oblongata, significantly higher concentrations of noradrenaline than did H rats. 5. Differences in brain noradrenaline may explain the inherited susceptibility or resistance to hypertension in H and N rats.

Animals↗

Sodium chloride preference in hypertensive (H) and normotensive (N) rats.

Salt consumption was compared in two strains of rats, selected for their disparate proneness (strain "H") or resistance (strain "N") to Doca-salt hypertension. NaCl intake was similar in "H" and "N" rats prior to an following administration of Doca, while their respective blood pressures at the end of this experiment was 178 +/- 5mm Hg vs. 134 +/- 3 mm Hg. Thus, disparate responses of the blood pressure to Doca in the two strains cannot be ascribed to differences in salt intake. In another study, salt preference was tested in "H" and "N" rats by two-bottle self-selecting technique. Before Doca, saline preference in "H" rats averaged 60.3 +/- 5.8% of total daily fluid consumption, vs 18 +/- 4.2% in "N" rats. Following Doca treatment for 3 weeks the respective values were 96 +/- 1.7% vs 67 +/- 6.6%. Thus Doca treatment enhanced salt appetite in both strains, but salt preference remained significantly higher in the "H" rats. The increased susceptibility to hypertension and enhanced salt appetite in the "H" rat, corroborates similar reports in the Okamoto "SH" rat. In the Brookhaven "S" rat, however, susceptibility to hypertension is associated with salt avoidance. The conflicting data do not support a unified concept of a genetically determined link between salt appetite and proneness to hypertension.

Animals↗

Experimentally produced hypertension and aortic acid esterase.

The effect of hypertension, which is known to enhance atherosclerosis, on acid esterase activity of rat aortic wall was studied histochemically. The purpose was to test our notion that atherogenesis depends on the balance between supply of lipids to the arterial smooth muscle cells and the lysosomal esterase activities. Hypertension was produced in rats by unilateral nephrectomy and administration of desoxycorticosterone acetate and sodium chloride. The animals reacted with varying degrees of hypertension. In rats with hypertension of a sufficiently high degree and of long duration, inhibition of aortic acid esterase activities occurred. No inhibition of these enzymes occurred in the other organs examined.

Animals↗

Obstructive jaundice associated with carcinoma of the prostate.

An unusual case of prostatic carcinoma presenting as severe obstructive jaundice is reported. After treatment with stilbestrol and bilateral orchidectomy, liver function tests became normal and lung metastases disappeared. During a second episode of jaundice due to serum hepatitis, liver function deteriorated following stilbestrol administration, and the drug was temporarily discontinued. The patient has been followed up for three years and liver function tests remain normal.

Adenocarcinoma↗