Prevalence of carotid artery lesions in renal fibromuscular dysplasia.
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Carotid Artery Diseases↗
Biomedical subjects
M Bursztyn
Publications and source records attributed to M Bursztyn.
Insulin resistance in spontaneously hypertensive rats but not in deoxycorticosterone-salt or renal vascular hypertension.
OBJECTIVE: To investigate whether the reported association between insulin resistance and hypertension in spontaneously hypertensive rats (SHR) is a primary defect or a secondary phenomenon in hypertension. DESIGN: Comparisons of glucose metabolism between three groups of hypertensive rats: deoxycorticosterone (DOCA)-salt hypertensive rats; two-kidney, one clip renovascular hypertensive (RVH) rats; SHR; and their respective control groups. There was also an additional group of weight-matched SHR and respective Wistar-Kyoto (WKY) controls. METHODS: A trace amount of 3H-deoxyglucose (3H-DOG) was administered in vivo to evaluate its plasma half-life and tissue uptake. In vitro adipose tissue segments were incubated with 14C-glucose and increasing doses of insulin. RESULTS: Compared with age-matched WKY rats, SHR had significantly higher insulin levels, longer plasma half-life and lower 3H-DOG uptake by heart and striated muscle. Plasma glucose levels and incorporation of 14C-glucose into CO2, triglycerides and glycogen by adipose tissue in response to increasing insulin concentrations was similar for both groups of SHR and WKY rats. No differences were found between hypertensive rats and controls in either the DOCA or RVH groups. CONCLUSION: Evidence of insulin resistance in spontaneous, but not secondary, rat hypertension indicates that the resistance is a primary rather than a secondary event in hypertension.
Animals↗
Improved kidney function with cilazapril in hypertensive type II diabetics with chronic renal failure.
The purpose of this study was to determine efficacy and safety of the angiotensin converting enzyme inhibitor, cilazapril, in the treatment of hypertensive diabetics with renal insufficiency. Fifteen type II diabetics with hypertension and chronic renal insufficiency aged (mean +/- SD) 64 +/- 7 years were studied in a regional clinic and university hospital hypertension unit. The blood pressure was measured biweekly. Urinary collections were done after 2 weeks of placebo and 8 weeks of cilazapril treatment. The blood pressure decreased from 176 +/- 15/105 +/- 9 to 164 +/- 11/95 +/- 9 mm Hg and serum creatinine from 197 +/- 69 to 179 +/- 73 mumol/L. The creatinine clearance rose from 41.6 +/- 11.4 to 47.4 +/- 14.9 ml/min, while protein excretion decreased from 0.8 +/- 1.3 to 0.5 +/- 0.8 g/24 h (p less than 0.05). The blood pressure change was inversely correlated with the creatinine clearance change (r = -0.5, n = 15, p less than 0.05). In these high-risk patients, 8 weeks of cilazapril treatment improved both blood pressure control and renal function but renal function improved most in the patients whose blood pressure changed the least.
Aged↗
Effects of a novel renin inhibitor in patients with essential hypertension.
The effects of A-64662, a new specific renin inhibitor, on plasma renin activity (PRA) and blood pressure (BP) were studied for the first time in patients with essential hypertension. A single intravenous bolus of vehicle, 0.001, 0.003, 0.01, 0.03, and 0.1 mg/kg was given to the first four patients, maintained on a constant 100 mEq Na diet. PRA was promptly reduced from 3.4 +/- 2.9 (mean +/- SEM) to 0.2 +/- 0.06 ng/ml/h, a 94% inhibition with the smallest dose, and to undetectable levels (less than 0.1 ng/ml/h) with the larger ones. However, BP did not change within this dose range. The subsequent seven patients received larger doses ranging from 0.2 to 1.0 mg/kg. In three cases, there was reduction in BP on the second dosing day, at doses of 0.4, 0.7, and 1 mg/kg. All responses were late (at 110 min after the injection), transient, and unrelated to baseline PRA. These results strongly suggest that there is a dissociation between the effectiveness of A-64662 in inhibiting PRA and its blood pressure lowering effect in hypertensive patients.
Adult↗
Effect of aging on vasopressin, catecholamines, and alpha 2-adrenergic receptors.
To characterize normal changes with aging, we measured plasma levels of epinephrine, norepinephrine, and vasopressin, as well as alpha 2-adrenergic receptor numbers (Bmax) and the antagonist dissociation constant (Kd) from platelet-derived membranes of white, younger (aged 28 +/- 6 years, n = 30) and older (aged 70 +/- 4 years, n = 41) normotensive, healthy volunteers. There were no differences in resting vasopressin or epinephrine levels at 0.83 +/- 0.83 and 360 +/- 120 pmol/L in the younger versus 1.0 +/- 0.2 and 450 +/- 420 in the older subjects, respectively. However, plasma norepinephrine was significantly higher in the older (2.87 +/- 1.34 nmol/L) versus the younger subjects (1.50 +/- 0.53 nmol/L, P less than .01). Platelet alpha 2-receptor numbers were significantly lower in the older subjects at 289 +/- 79 fmol/mg protein versus 388 +/- 81 fmol/mg protein in the younger subjects (P less than .01), compatible with but not proof of down-regulation by norepinephrine. However, Kd, representing receptor affinity, was similar in both groups. Therefore, studies of hormone and receptor status in various pathologic conditions should always take into account the normal changes attributable to the age of the subject population.
Adult↗
Pressor hormones in elderly hypertensive persons. Racial differences.
The purpose of this study was to examine pressor hormones and platelet alpha 2-adrenergic receptors in elderly unmedicated free-living subjects. Eighty-seven subjects, 70 +/- 5 years old (mean +/- SD), hypertensive or normotensive (blood pressure less than 160/90 mm Hg) were recruited for measurement of blood levels of norepinephrine, epinephrine, and vasopressin, as well as density and affinity of alpha 2-adrenergic receptors from platelet membranes, assessed by maximal binding (Bmax) and dissociation constant (Kd) of rauwolscine. They were separated into white hypertensive (n = 22) or normotensive (n = 41), and black hypertensive (n = 11) or normotensive (n = 13) groups, with similar age distribution throughout and similar blood pressure levels in the hypertensive and normotensive groups. Vasopressin was higher in the black hypertensive than white hypertensive group (1.5 +/- 1.0 vs. 0.7 +/- 0.5 pg/ml, respectively, p less than 0.005), whereas epinephrine correlated inversely with diastolic blood pressure (r = -0.7, p less than 0.02, in the black hypertensive group). Kd was higher in the black normotensive group than in the other groups (1.6 +/- 0.6 vs. 1.0 +/- 0.2, 1.1 +/- 0.3, or 1.0 +/- 0.3 nM in the white normotensive, black hypertensive, or white hypertensive group, respectively, p less than 0.002). Bmax was no different among groups but was significantly correlated with vasopressin levels for the whole group (r = 0.4, p less than 0.0004) although no such correlation existed within the black hypertensive group. The data suggest that various vasoconstrictor systems participate to different extents in the mechanisms generating and sustaining hypertension in elderly white and black subjects.
Aged↗
Renin inhibition with A-64662: effect on blood pressure and hormonal response in man.
We studied the effects of intravenous injections of the renin inhibitor A-64662 on blood pressure, plasma renin activity (PRA), angiotensin II (Ang II) and aldosterone levels in patients with essential hypertension. While PRA was completely suppressed with doses as small as 0.001 microgram/kg, blood pressure was affected only in a few instances in doses of 0.4-1.0 mg/kg. In the six patients in whom Ang II and aldosterone results were available these hormones were concomitantly reduced with PRA, although the PRA inhibition lasted much longer (up to 24 h). There was little relationship between the blood pressure changes and plasma levels of renin activity, Ang II and aldosterone, suggesting that the plasma pool of these variables may not be the crucial factor determining blood pressure responses in patients with essential hypertension.
Aldosterone↗
Hypertension in the aging patient. Implications for the selection of drug therapy.
Although earlier debates had questioned the wisdom of treating hypertension in elderly patients, it is now becoming apparent that such treatment is warranted. Systolic hypertension, which prevails in this population, is more closely correlated to hypertensive complications than is diastolic blood pressure. Recent multicenter trials have demonstrated that in this age group, as in younger patients, control of hypertension can significantly decrease the rate of cardiovascular and cerebrovascular events. Many effective antihypertensive agents are available today, but elderly patients, because of their hemodynamic and biochemical characteristics, are particularly vulnerable to the common side effects of most drugs. However, the two newer classes of drugs (the angiotensin-converting enzyme inhibitors and the calcium channel blockers) offer several advantages in terms of favorable hemodynamic and biochemical profiles, convenience of dosing, and maintenance of quality of life. These characteristics justify choosing these agents as first-line therapy for hypertension.
Aged↗
Intravenous dilevalol in the treatment of severe hypertension.
Dilevalol, the stereoisomer of labetalol, was given in repeated incremental intravenous bolus injections to 10 patients with severe hypertension requiring urgent blood pressure lowering. The mean cumulative dose of dilevalol was 445 +/- 165 mg. Blood pressure was reduced from 201 +/- 33/131 +/- 13 to 150 +/- 12/109 +/- 7 mm Hg (p less than 0.01) and heart rate did not change significantly. In only one patient was the study discontinued because of side effects (nausea and dizziness). There were no other clinically significant adverse reactions and no change was observed in electrocardiogram or routine biochemical and hematologic tests. Five of these patients, who achieved diastolic blood pressure of less than or equal to 105 mm Hg, participated in a subsequent outpatient phase of the study with combination of oral dilevalol with hydrochlorothiazide. Of these only one achieved good blood pressure control. We concluded that in such severely hypertensive patients intravenous dilevalol was safe and effective for the short-term lowering of blood pressure. However, long-term outpatient maintenance with this drug needs further evaluation.
Adult↗
The absence of long-term therapeutic effect of calcium channel blockade in the primary aldosteronism of adrenal adenomas.
The absence of long-term effect of calcium channel blockers in primary aldosteronism due to adrenal adenoma is described in two patients. Calcium entry channel blockers, which were claimed to be a new medical therapy for primary aldosteronism, neither prevented the increase of plasma aldosterone nor decreased potassium levels over time in these patients. The drugs did not even lower blood pressure in one patient. Whereas calcium channel blockers may be effective in adrenal hyperplasia, they are apparently not effective enough in the long term treatment of patients with primary aldosteronism due to adrenal adenoma.
Adenoma↗
Nifedipine in the treatment of hypertension in systemic lupus erythematosus.
Treatment of hypertension in systemic lupus erythematosus (SLE) may be complicated by unwanted immunologic vascular and renal side effects of drugs. The safety of long-acting nifedipine tablets was studied in 8 SLE hypertensive subjects for six months. Nifedipine reduced blood pressure from a mean 151.9 +/- 10/103.7 +/- 8.6 mmHg to a mean of 130 +/- 14.1/87.5 +/- 5 mmHg. There was no deterioration of renal function or of hematologic or immunologic indices during that period. We believe nifedipine is a safe and effective hypotensive drug in SLE, either alone or combined with beta blockers and diuretics.
Antibodies↗
Myelodysplastic syndrome: a review of 35 patients.
Thirty-five patients with myelodysplastic syndromes were retrospectively classified according to the FAB classification (French-American-British Cooperative Study Group). Their prognosis was found to be dependent mainly on the presence of blasts in bone marrow examination. Those with an excess of blasts in their bone marrow had a median survival of 30 months in contrast to 66 months in those without blasts. These results were compared with those of seven recent reported series.
Adult↗
Muscle enzyme elevation in carbamazepine intoxication.
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Adult↗
Hypertensive crisis associated with nifedipine withdrawal.
A 71-year-old hypertensive patient experienced a severe hypertensive crisis. His blood pressure was 300/200 mm Hg three days after nifedipine therapy was discontinued. He had been taking nifedipine together with methyldopa. During five months on the combined treatment, his blood pressure had not risen higher than 170/100 mm Hg. A severe hypertensive crisis following abrupt nifedipine withdrawal has not been previously reported, to our knowledge. We recommend that caution be used when abrupt cessation of nifedipine therapy is considered in the treatment of hypertension.
Aged↗
Nifedipine-induced periorbital edema.
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Angina Pectoris↗
Long-acting nifedipine in moderate and severe hypertensive patients with serious concomitant diseases.
Long-acting nifedipine tablets were given to 47 severely and moderately hypertensive patients with renal insufficiency, cardiovascular, cerebrovascular, and peripheral vascular disease, diabetes mellitus, asthma, and systemic lupus erythematosus. Nifedipine substituted vasodilators (n = 22), was added to beta blockers and thiazides (n = 14), and was used alone (n = 11). In all three groups blood pressure was significantly reduced without aggravation of angina pectoris, intermittent claudication, cerebrovascular disease, or renal failure. Side effects were mild and transient. We found nifedipine tablets convenient and safe, as well as efficacious in patients with serious conditions.
Adult↗
Nifedipine as a substitute for converting enzyme inhibitors in the treatment of renovascular hypertension.
Nifedipine long acting tablets were substituted for converting enzyme inhibitors in eight patients with renovascular hypertension. A significant drop in blood pressure was observed. Nifedipine was shown to be as effective (in lowering blood pressure) as a drug that acts directly on the renin angiotensin system. These data offer support for previously reported findings that the action of angiotensin II is calcium mediated.
Adult↗