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Biomedical subjects

F Gross

Publications and source records attributed to F Gross.

At least 73 records · Page 4Linked to original sources
PubMed1982

Effect of dihydralazine on the renal kallikrein-kinin system of the rat.

Dihydralazine (0.1 mg/kg), injected intravenously into male Sprague-Dawley rats, caused a decrease in mean arterial blood pressure and an increase in renal plasma flow, while urine volume remained unchanged. Dihydralazine had no effect on kallikrein excretion in the urine and on kallikrein activity in the renal cortex. No correlation was found between renal kallikrein and either renal plasma flow or mean arterial blood pressure. The excretion of kinins in the urine rose markedly after the administration of dihydralazine; no correlation between urinary kinins and urinary or renal kallikrein was observed. Dihydralazine had no influence on the kininogen content of blood-free renal cortex. The enzymatic activity of kininase II in renal cortex was not impaired by dihydralazine. It is suggested that the increased formation of kinins within the kidney could be involved in the vasodilating and blood pressure lowering effect of dihydralazine.

Animals↗
PubMed1982

Assessment of susceptibility to measles and rubella.

We conducted a serological and questionnaire study of 755 US Merchant Marine Academy cadets (aged 16 to 29 years) and their parents to determine the cadets' susceptibility rate to measles and rubella and to see if there was any difference in the accuracy of cadet and parental histories of previous infection and vaccination. Approximately 4% of the cadets were susceptibility. We also determined the costs and the effectiveness of three alternative strategies for vaccinating susceptible adolescents and young adults: (1) vaccinating all persons regardless of past history; (2) serologically screening all persons and vaccinating only those who were susceptible; and (3) vaccinating all individuals who do not have physician-documented proof of proper vaccination, past infection (measles only), or serological immunity. The cost savings among the three alternatives are dependent on the proportion of potential vaccinees with records available for review and must be balanced against the proportion of susceptible persons protected by each alternative. We also found that a combined vaccination program for both measles and rubella is less costly than a program aimed at providing immunity to only one of the two diseases.

Adolescent↗
PubMed1982

Renal kallikrein activity and urinary kallikrein excretion in rats with experimental renal hypertension.

1. Rats were made hypertensive by ligating the aorta between the origins of both renal arteries. Sham-operated animals served as controls. Urinary and renal kallikrein activities, as well as plasma and renal renin activities, were measured 8 and 90 days after surgery. 2. Blood pressure was 155 +/- 6 mmHg on day 8 after aortic ligature and 142 +/- 6 mmHg on day 90; in controls pressures were 107 +/- 3 and 110 +/- 5 mmHg respectively. 3. Eight days after aortic ligature, kallikrein activity in the ischaemic kidneys was about 6.5 times, and in the non-ischaemic kidneys almost 2 times, that in controls. After 90 days the kallikrein activity was reduced to one-half of that in the controls in the ischaemic kidneys and it was normal in the contralateral. 4. The urinary kallikrein excretion of hypertensive rats was about one-third of that of the controls at both 8 and 90 days after aortic ligature. 5. The plasma renin activity in hypertensive rats was approximately seven times that in control animal 8 days after aortic ligature and did not differ from the control value after 90 days. Renin activity in the kidneys showed the same pattern as in other models of renovascular hypertension: elevation in the ischaemic kidney and reduction in the non-ischaemic one.

Animals↗
PubMed1982

Vasopressin in brain of spontaneously hypertensive rats.

In stroke-prone spontaneously hypertensive rats (SHRSP) and in normotensive Wistar-Kyoto rats (WKY), arginine vasopressin (AVP) was measured by means of a radioimmunoassay in the plasma, the pituitary gland, the hypothalamus, and the brain stem. In 6- and 14-wk-old SHRSP, the plasma concentration of AVP was lower than in age-matched WKY (P less than 0.01), whereas it was elevated at 28 wk of age (P less than 0.01). In the pituitary of 6-wk-old SHRSP, AVP was higher than in WKY (P less than 0.05), but no such difference was found in older rats. In the hypothalamus and the brain stem, AVP content was reduced in all age groups of SHRSP. Plasma osmolality was diminished in 28-wk-old SHRSP only (P less than 0.01), whereas hematocrit in all age groups was higher in SHRSP than in WKY. It is concluded that the secretion of AVP and possibly its synthesis in the hypothalamus are reduced in SHRSP. Whether the reduced AVP content in the brain stem is related to the sustained elevation of blood pressure has to be studied further.

Aging↗
PubMed1982

Contralateral renal function following unilateral renal artery constriction.

The acute (0.5-3.0 h) response of the contralateral kidney to unilateral renal artery constriction was studied in 7 pentobarbital-anesthetized dogs. Within 30 min after unilateral renal artery constriction to a pressure of about 60 mm Hg, contralateral vascular resistance, sodium excretion and filtration fraction increased significantly while glomerular filtration rate, blood flow and plasma flow did not change. Renin secretion decreased dramatically within 30 min, demonstrating a negative venous minus arterial plasma renin activity in some dogs. Unilateral renal artery constriction did not change the rate of angiotensin II extraction across the contralateral kidney or the urinary renin activity (measured in 4 dogs). These results indicate that the acute response of the contralateral kidney to unilateral renal artery constriction is somewhat different from that seen in the chronic state.

Angiotensin II↗
PubMed1981

[Captopril - profile of a new antihypertensive (author's transl)].

Captopril is a specific inhibitor of kininase II which is responsible for the conversion of angiotensin I into the active angiotensin II and also for the inactivation of bradykinin. In different types of experimental and clinical hypertension, Captopril has a pronounced blood pressure-reducing action particularly when it is given together with a diuretic. Serious side-effects have hitherto restricted the use of Captopril to patients who do not respond or do not respond satisfactorily to routine antihypertensives. Since it has been shown that a considerable improvement in disturbed hemodynamics in hypertension and in certain forms of heart failure can be achieved with quite low doses of the preparation (2 x 2 mg daily) the use of Captopril may be indicated in greater amounts in moderate and severe hypertension.

Angiotensin II↗
PubMed1981

Plasma catecholamines, noradrenaline metabolism and vascular response in desoxycorticosterone acetate hypertension of rats.

Mineralocorticoid hypertension was induced in male Wistar rats by the injection of desoxycorticosterone acetate (DOCA) in oily solution (2 X 5 mg/kg daily for 7 days) and of desoxycorticosterone trimethylacetate in a microcrystalline suspension (15 mg/kg every third day for 4 weeks). A 1% NaCl solution or demineralized water was given as drinking fluid. Four weeks after the beginning of treatment, mean arterial blood pressure was 161 +/- 3.8 mmHg in DOCA-saline treated and 140 +/- 5.9 mmHg in DOCA-water-treated rats. Basal plasma levels of noradrenaline and adrenaline did not differ in conscious, unrestrained DOCA-treated rats and in control rats 3, 7 and 28 days after the beginning of hormone administration. Furosemide (50 mg/kg) caused within 30 min the same degree of diuresis and natriuresis in DOCA-treated and in control rats, but the plasma noradrenaline concentration in DOCA-treated rats rose to a higher level than in the controls. The isolated perfused hearts of rats which received DOCA for 7 and 28 days, respectively, had a reduced uptake of [3H]noradrenaline as compared to the controls. In isolated perfused hindlimb preparations from rats which had received DOCA for 7 days, the dose-response curve to noradrenaline but not that to KCl was shifted to the left. However, when DOCA and saline were given for 28 days, besides a higher sensitivity to noradrenaline an increased maximum response was observed with both noradrenaline and KCl. It is concluded that adrenergic tone is enhanced during the development of DOCA hypertension. Since the changes in the sympathetic nervous system in DOCA-water-treated rats, which had a less pronounced hypertension, were similar to those in DOCA-NaCl-treated rats, alterations in adrenergic vascular tone were not directly related to the level of the blood pressure.

Animals↗
PubMed1981

Yohimbine diastereoisomers: cardiovascular effects after central and peripheral application in the rat.

The cardiovascular effects of four yohimbine diastereoisomers, yohimbine, rauwolscine, corynanthine, and 3-epi-alpha-yohimbine, were compared in urethane-anaesthetized and conscious, normotensive Sprague-Dawley rats. Intravenous cumulative infusions (10--500 microgram) of the drugs to anaesthetized rats decreased blood pressure and blunted the pressor response to intravenous adrenaline injections. Corynanthine was the most potent isomer in this regard, followed by yohimbine, rauwolscine, and 3-epi-alpha-yohimbine. Depressor responses following intravenous bolus doses (40 microgram) showed a similar ranking. Intraventricular injections of yohimbine to anaesthetized rats decreased blood pressure dose-dependently, as did injections of corynanthine and rauwolscine. Responses indicated the ranking to be yohimbine greater or equal to rauwolscine greater than corynanthine for this effect at the 40 microgram dose. Heart rate was also decreased by these isomers, but not in a dose-dependent fashion. In conscious rats, the intraventricular injection of these isomers (20 microgram) increased blood pressure and heart rate. No differences were noted in terms of blood pressure responses; but, in causing tachycardia, the ranking was rauwolscine greater than yohimbine greater than corynanthine. These data suggest that after intraventricular application in anaesthetized rats, the effects of these alpha-adrenoceptor blockers are related to their individual affinity for the alpha 2 adrenoceptor.

Animals↗