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Biomedical subjects

I Kobrin

Publications and source records attributed to I Kobrin.

At least 73 records · Page 4Linked to original sources
PubMed1984

Long-term renal hemodynamic effects of nadolol in patients with essential hypertension.

Renal and systemic hemodynamic effects of nadolol, a nonselective beta-adrenergic-blocking agent, were determined over a 2-year period in eight patients with essential hypertension. Arterial pressure and heart rate remained significantly reduced for the full 2 years in all eight patients. Renal blood flow and plasma volume remained unchanged, and renal vascular resistance significantly decreased. Serum creatinine levels decreased from pretreatment values, suggesting improved glomerular filtration rates. These data demonstrate the favorable renal hemodynamic effects of nadolol monotherapy in patients with uncomplicated essential hypertension during a prolonged treatment program.

Adrenergic beta-Antagonists↗
PubMed1984

Reduced cardiac mass by nitrendipine is dissociated from systemic or regional haemodynamic changes in rats.

The effects of prolonged treatment (3 weeks) with nitrendipine (10 mg X kg-1 twice daily) on systemic and regional haemodynamics and cardiac mass were studied in SHR and WKY rats. Nitrendipine markedly decreased mean arterial pressure (26.0 +/- 0.4 vs 19.9 +/- 0.6 kPa, P less than 0.01) and total peripheral resistance (0.090 +/- 0.004 vs 0.066 +/- 0.004 U X kg-1, P less than 0.01) in SHR without significantly affecting cardiac output and heart rate, whereas in the WKY rats no significant systemic haemodynamic changes were noted. Increased splanchnic blood flow and a reduced splanchnic vascular resistance were found in the WKY rats; however, in the SHR rats, blood flows (ml X min-1 X g tissue-1) increased and organ vascular resistances (kPa X ml-1 X min-1 X 100 g tissue-1) decreased significantly (P less than 0.01) in the heart (5.25 +/- 0.28 vs 7.27 +/- 0.31 and 0.04 +/- 0.00 vs 0.02 +/- 0.00; P less than 0.01) and kidneys (6.53 +/- 0.4 vs 7.98 +/- 0.2 and 0.03 +/- 0.00 vs 0.02 +/- 0.00; P less than 0.01), respectively. Nevertheless, in both rat strains, absolute cardiac mass and left ventricular weight were reduced; but in the SHR rats, the relative weight of the heart and left ventricle to body weight was also reduced significantly (3.79 +/- 0.06 vs 3.31 +/- 0.09; P less than 0.01 and 2.85 +/- 0.06 vs 2.70 +/- 0.06; P less than 0.01, respectively). Thus, these studies show that nitrendipine, a slow-entry channel calcium blocker, regressed cardiac mass in rats through mechanisms that may be dissociated from their haemodynamic changes.

Animals↗
PubMed1984

Diurnal variation of blood pressure in elderly patients with essential hypertension.

Twenty-one elderly patients with essential hypertension, all over 65 years of age, were subjected to automated noninvasive 24-hour blood pressure measurement. Readings were obtained every 7.5 minutes throughout the day. The data were analyzed with respect to: correlation between office and ambulatory pressure measurements; possible differences in the circadian blood pressure pattern; and the existence of hypertensive or atherosclerotic cardiovascular complications. In all patients, the office systolic pressures were significantly higher than the ambulatory daytime pressures; diastolic pressures were similar. At night, two patterns of blood pressure emerged. In one there was a further fall in both systolic and diastolic pressures to normotensive levels, whereas the other pattern revealed no change in diastolic pressure, although systolic pressure increased significantly to similar levels as measured in the office. The prevalence of hypertensive or atherosclerotic cardiovascular complications in the patients with the first pattern was significantly less than in the group of patients with the second pattern (chi square, P less than 0.025). The data reported herein indicate that ambulatory blood pressure monitoring may help in the overall clinical evaluation of elderly patients with hypertension.

Aged↗
PubMed1984

Role of site of microsphere injection and catheter position on systemic and regional hemodynamics in rat.

The influences of the site of microsphere injection (intra-atrial vs. intraventricular) and positioning of the left ventricular catheter (aortoventricular vs. atrioventricular) on systemic, renal, and coronary hemodynamics were evaluated in anesthetized rats. The effect of anesthesia on aortoventricular catheter positioning was also evaluated. In anesthetized and open-chest preparations, the systemic and renal hemodynamics were not affected by catheter position or site of microsphere injection; however, myocardial blood flow was dependent on these variables. Variations in coronary blood flow were significantly greater when the catheter was in the aortoventricular position (34 +/- 3%) than with an atrioventricular catheter (11 +/- 2%, P less than 0.01), irrespective of whether the microspheres were injected into the atrium or ventricle. Comparison of anesthetized and conscious rats with aortoventricular catheter indicated lesser variability in coronary blood flow in the conscious rats (P less than 0.01). Therefore, the greater variability of coronary flow measurements in anesthetized rats was caused by the position of the cardiac catheter in the aortoventricular route. However, the variability caused by the aortoventricular catheter was much less in conscious rats. Therefore, coronary flow hemodynamic measurements (microsphere technique) are less variable when they are made in conscious rats.

Anesthesia, General↗
PubMed1984

Immediate hemodynamic effects of a dopamine-receptor agonist (fenoldopam) in patients with essential hypertension.

Systemic, splanchnic, and renal hemodynamics, intravascular volume, and reflexive and endocrine changes were measured before and after a single dose of fenoldopam, a novel antihypertensive agent that acts through stimulation of specific dopamine receptors. A 13% reduction in mean arterial pressure was mediated by a fall in total peripheral resistance association with an increase in cardiac index, heart rate, stroke volume, left ventricular ejection rate, and circumferential fiber shortening. Renal blood flow increased, thereby reducing the renal vascular resistance by more than 40%. In contrast, splanchnic hemodynamics failed to change. Likewise, there were no changes in intravascular volume, plasma renin activity, or norepinephrine, serum aldosterone, or prolactin levels.

Administration, Oral↗
PubMed1984

Immediate hemodynamic changes produced by urapidil in normotensive and spontaneously hypertensive rats.

The immediate effects on regional and systemic hemodynamics of urapidil (1 mg/kg IV), a recently synthesized vasodilator with a possible combined central and peripheral action, were studied in spontaneously hypertensive (SHR) and normotensive (WKY) rats. Maximal decrease in mean arterial pressure was achieved within the first minute after injection (154 +/- 4 vs 113 +/- 6 mm Hg in SHR and 111 +/- 4 vs 82 +/- 4 mm Hg in WKY, p less than 0.01). This effect was accompanied by a transient (10 min) significant increase in heart rate in both strains. There was a significant fall in total peripheral resistance (0.43 +/- 0.02 vs 0.30 +/- 0.02 U/kg in WKY and 0.62 +/- 0.03 vs 0.43 +/- 0.03 U/kg in SHR, p less than 0.01) and rise in cardiac index 15 min after drug injection (371 +/- 9 vs 425 +/- 12 ml/min/kg in WKY and 395 +/- 8 vs 432 +/- 112 ml/min/kg in SHR, p less than 0.01). Organ vascular resistance decreased significantly in all the organs of /KY and most of the organs of SHR rats. However, a significant increase in blood flow was observed only in skeletal muscle. The data indicate that urapidil is a potent hypotensive agent. The pressure fall is mediated through a decreased total peripheral resistance that is distributed through all circulations. The increased cardiac output and heart rate are most likely reflexly induced.

Animals↗
PubMed1984

Nitrendipine: hemodynamic effects in conscious normotensive and spontaneously hypertensive rats.

The effects of immediate (1 h) and prolonged (3 weeks) treatment with nitrendipine on systemic and regional hemodynamics were investigated in Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Mean arterial pressure (MAP) was significantly (p less than 0.05) decreased in both WKY (125 +/- 2 versus 108 +/- 3 mm Hg) and SHR (189 +/- 5 versus 141 +/- 10 mm Hg) 1 h following oral nitrendipine administration (10 mg/kg). This was associated with a significant (p less than 0.05) decrease in total peripheral resistance index (TPRI) (0.48 +/- 0.03 versus 0.38 +/- 0.02 units/kg, WKY; 0.69 +/- 0.04 versus 0.56 +/- 0.05 units/kg SHR) but no change in cardiac index (CI). A significant (p less than 0.05) increase in heart rate (HR) (374 +/- 14 versus 407 +/- 11 beats/min) was observed only in WKY. Vascular resistances were reduced significantly (p less than 0.05) in heart and kidney in both SHR and WKY as well as the brain and splanchnic organs of the WKY. Resistance increased significantly in SHR skin. The MAP reduction with prolonged treatment (196 +/- 3 versus 181 +/- 4 and 150 +/- 5 mm Hg) was also associated with a reduced TPRI (0.73 +/- 0.03 versus 0.64 +/- 0.07 and 0.50 +/- 0.03 units/kg) in SHR treated for 3 weeks with nitrendipine (10 and 20 mg/kg/day, respectively). No changes in systemic hemodynamics were observed in similarly treated WKY. Skeletal muscle and splanchnic vascular resistances were reduced (p less than 0.05) in nitrendipine-treated WKY (20 mg/kg/day).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Systemic and renal effects of enalapril and its effects on cardiac mass.

Enalapril is a new angiotensin converting enzyme (ACE) inhibitor and has been shown to be of benefit in the treatment of both renovascular and essential hypertension. We have studied the systemic and renal haemodynamic, biochemical and cardiac adaptive changes induced by this agent in eight patients with essential hypertension before and after 12 weeks of therapy. Mean arterial pressure fell from 110 to 90 mmHg (P less than 0.01) and this was mediated through a fall in total peripheral resistance, cardiac index and heart rate remaining unchanged. Renal plasma flow rose in six patients. Renal vascular resistance fell in all patients (P less than 0.01). Left ventricular mass index was reduced from a mean of 166 +/- 29 to 117 +/- 8 g/m2 (P less than 0.05) and systolic ventricular function remained unchanged. Thus, enalapril lowers arterial pressure by reducing total peripheral resistance, has favourable haemodynamic effects on the kidney, and produces a reduction in left ventricular mass within three months of the start of therapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1984

Urapidil in normotensive and spontaneously hypertensive rats: the effects on systemic and regional haemodynamics and cardiac mass.

The effects of treatment for three weeks with urapidil (10 mg/kg p.o. twice daily) on systemic and regional haemodynamics and cardiac mass were studied in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Urapidil decreased mean arterial pressure and total peripheral resistance index (176 +/- 3 versus 145 +/- 5 mmHg and 0.61 +/- 0.02 versus 0.49 +/- 0.02 units, respectively; each P less than 0.01) in SHR without affecting heart rate, cardiac index or cardiac mass. No systemic haemodynamic changes were observed in WKY rats. All organ vascular resistances decreased significantly in SHR and blood flow increased to skin (P less than 0.01) and kidneys (P less than 0.05). These data indicate that urapidil is a potent antihypertensive agent in SHR which reduced mean arterial pressure through a decreased total peripheral resistance that was distributed throughout all circulations. Despite these haemodynamic changes, cardiac mass did not change.

Animals↗
PubMed1984

Stable red cell mass despite contracted plasma volume in men with essential hypertension.

Red blood cell mass, plasma volume, and renal and systemic hemodynamic measurements were evaluated in 24 normotensive men (group 1), 45 men with mild essential hypertension (group 2), and 43 men with moderate to severe essential hypertension (group 3). Despite significant hemodynamic differences between the groups and although plasma volume was contracted, the increased hematocrit in the third group of patients was not explained by an increase in red blood cell mass. Because this was the case in all groups, it demonstrates that the increased hematocrit in patients with more severe essential hypertension is solely attributable to the contracted plasma volume.

Adult↗
PubMed1983

Kidney involvement in systemic lupus erythematosus and Fabry's disease.

A young female patient with both systemic lupus erythematosus (SLE) glomerulonephritis and glomerular glycolipid storage of Fabry's disease is described. The causal relationship between the two conditions is discussed and it is suggested that accumulated immunogenic galactocerebroside may have incited an autoimmune disease such as SLE.

Adolescent↗
PubMed1983

The combination of propranolol and nifedipine in the treatment of hypertension: acute and long term effects.

The long term efficacy and tolerability of nifedipine combined with propranolol was assessed in a group of hypertensive patients inadequately controlled on propranolol alone. Twenty-six subjects were initially treated with propranolol in a constant daily dose of 160-240 mg, for up to 4 weeks. Nifedipine, 30 mg/day, was added and the dose was titrated upwards to 90 mg/day to achieve normal blood pressure. In 22 patients receiving the combined therapy for 14-30 weeks, mean arterial pressure dropped from 138 +/- 3 mmHg to 102 +/- 2 mmHg. Thirteen patients experienced untoward effects, and 4 discontinued the study. In the remaining 9, side effects were mild and well tolerated. Seventeen patients were subsequently treated sequentially with propranolol alone, combined therapy and nifedipine alone, to assess the efficacy of each regimen and the additive effect of each drug. The combined regimen was found to be more effective than either drug alone. A subgroup continued either combined therapy (14) or nifedipine monotherapy (3) and was followed for up to 9 months. Blood pressure control was maintained in the majority, but 4 more patients dropped out because of side effects. We conclude that the long term use of nifedipine combined with propranolol is effective and relatively well tolerated, and may offer an alternative approach to the treatment of moderately severe hypertension.

Adult↗