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Biomedical subjects

M D Blaufox

Publications and source records attributed to M D Blaufox.

At least 19 recordsLinked to original sources
PubMed1992

Renin predicts diastolic blood pressure response to nonpharmacologic and pharmacologic therapy.

OBJECTIVE: Plasma renin activity was measured at baseline and 6 months in a trial of nonpharmacologic therapy of mild hypertension to determine whether plasma renin activity predicts the diastolic blood pressure (DBP) response to nonpharmacologic therapy. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial of volunteers from the general community with mild hypertension (DBP between 90 and 100 mm Hg), off all antihypertensive therapy at baseline, treated in special research clinics (n = 593). INTERVENTIONS: Subjects were randomly assigned to usual, weight loss, or low sodium/high potassium diet and then randomly assigned to receive placebo, chlorthalidone, or atenolol. MAIN OUTCOME MEASURES: Renin was analyzed as plasma renin activity and as a renin index (logarithm of 24-hour urinary sodium excretion times logarithm of plasma renin activity) (593 patients at baseline and 6 months) to correct for varied sodium intakes. The DBP was measured using the random zero device. RESULTS: Change in DBP at 6 months could be predicted from baseline plasma renin activity or renin index. The DBP was decreased after 6 months of therapy by 2 mm Hg for each unit increase in baseline plasma renin activity and by 0.16 mm Hg for each unit increase in baseline renin index. Patients in the highest renin index quartile had a greater DBP response to atenolol therapy, and patients in the lowest renin index quartile had a greater DBP response to chlorthalidone therapy. Weight loss diet achieved a greater reduction in DBP in patients with higher baseline renin index and had an additive effect on DBP response in both of the drug groups. Patients on a weight loss diet receiving placebo in the highest baseline renin index quartile had a reduction in DBP of 12.4 mm Hg, compared with 4.4 mm Hg in the lowest baseline renin index quartile (P = .009). A low sodium/high potassium diet had a lesser effect than a weight loss diet on pharmacologic therapy. As with the weight loss diet, patients on a low sodium/high potassium diet in the highest baseline renin index quartile had a greater reduction in DBP than patients in the lowest baseline renin index quartile. CONCLUSIONS: These data suggest a significant relationship between baseline levels of plasma renin index and the likelihood of success of nonpharmacologic treatment of hypertension.

Adult↗
PubMed1992

The Trial of Antihypertensive Interventions and Management (TAIM) Study. Final results with regard to blood pressure, cardiovascular risk, and quality of life.

The Trial of Antihypertensives Interventions and Management (TAIM) was a multicenter double-blind placebo-controlled clinical trial of drug and diet combinations for the treatment of mild hypertension among 878 participants, ages 21 to 65, 110% to 160% ideal weight, and with baseline diastolic blood pressure 90 to 100 mm Hg. The drugs used were placebo, chlorthalidone (25 mg/daily) or atenolol (50 mg/daily). The diets studied were usual, weight loss, sodium reduction/potassium increase. Trial end points were 6-month diastolic blood pressure change, cardiovascular risk change, and quality of life change. Either drug combined with weight loss produced the greatest blood pressure reduction of 15 mm Hg, compared to 8 mm Hg on placebo/usual diet. Adding sodium restriction to either drug did not enhance blood pressure lowering effect. Drugs outperformed diet in terms of antihypertensive effect. However, those on placebo and assigned to weight reduction who lost more than 4.5 kg and those on sodium restriction who reduced sodium to less than 70 mEq daily lowered blood pressure to a similar extent as those on either of the two drugs alone. Cardiovascular risk at 6 months relative to baseline ranged from 0.85 in weight loss/atenolol subgroup to 1.04 in the usual diet/chlorthalidone subgroup. Blacks were more responsive to chlorthalidone plus weight loss and whites to atenolol plus weight loss. Quality of life, as measured by scales of distress and well-being, was favorably affected by weight reduction. Although there were few side effects of the drugs and most patients improved on most parameters, sexual complaints were worsened among those on chlorthalidone and usual diet compared to placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of antihypertensive therapy on weight loss. The Trial of Antihypertensive Interventions and Management Research Group.

We report the effect of weight changes of the type of antihypertensive medication prescribed in a trial of the relative efficacy of drug and dietary measures in mild hypertension. The Trial of Antihypertensive Interventions and Management studied 878 mildly hypertensive individuals randomly assigned, in a 3 x 3 design, to no diet change, weight loss, or a low sodium-high potassium diet and to placebo, 25 mg chlorthalidone, or 50 mg atenolol. The type of drug prescribed affected weight change with all diets. The drug effect on weight change, present in all groups at 6 months, was most pronounced in those randomly assigned to the weight loss diet, where the placebo group lost 4.4 kg, the atenolol group lost 3.0 kg, and the chlorthalidone group lost 6.9 kg. The group differences were attenuated but persisted at 24 months. We suggest that the antihypertensive drug prescribed affects the success of a conjoint weight loss program and speculate that the difference between the drugs may be due to their intrinsic effects on the sympathetic nervous system and related metabolic changes.

Atenolol↗
PubMed1992

The effect of captopril on glucoheptonate uptake in experimental renal artery stenosis.

This study attempted to evaluate the role of glucoheptonate (GHA) in captopril renography in an in vivo laboratory investigation in which postcaptopril glucoheptonate uptake was analysed in awake 2KlC hypertensive rats. Clamped kidney uptake in a previous study was greater in the poststenotic kidney than in the normal kidney (P = 0.01) in rats with mild renal artery stenosis. A glucoheptonate renogram protocol was developed for use in rats anaesthetized with sodium pentobarbital. An 123I-hippuran scan was performed to determine the relative renal function, followed by a control 99Tcm-GHA scan. Five minutes after administering captopril, another 99Tcm-GHA scan was performed. Relative renal uptake was determined between 30 and 90 s postinjection. 99Tcm-GHA uptake in the clamped kidney was more than 50% of total uptake in 3/9 of the abnormal rats' control scans. No abnormal rats clamped kidney 99Tcm-GHA uptake was greater than 50% in the postcaptopril scans. Captopril reduced GHA uptake in all nine of the animals with baseline scans. These findings suggest that the laboratory observation of captopril induced paradoxically increased 99Tcm-GHA uptake in renal artery stenosis may not be observed scintirenographically. Moreover, the data support a potential value of glucoheptonate in captopril renography.

Animals↗
PubMed1992

Renal functional response to captopril during diuretic therapy.

Antihypertensive agents may modify the renal effects of angiotensin converting enzyme inhibition (ACEI). This potential interaction, which is important in the diagnosis of renovascular hypertension was studied in two rat models with and without diuretic treatment prior to ACEI. Acute intravenous administration of furosemide or hydrochlorothiazide in one-kidney, one-clamp animals (1K1C) did not change glomerular filtration rate (GFR) or effective renal plasma flow (ERPF). ACEI administration after furosemide and hydrochlorothiazide decreased GFR (p less than 0.001, p less than 0.01) but not ERPF. Chlorothiazide administered to 1K1C prior to ACEI, decreased GFR (p less than 0.02) but not ERPF captopril administration to 1K1C which received hydrochlorothiazide intraperitoneally for 7-10 days decreased GFR (p less than 0.007) and ERPF (p less than 0.02), while two-kidney, one-clamp animals (2K1C) decreased GFR only in the clamped kidney (p less than 0.005). ERPF in 2K1C increased only in the contralateral kidney (p less than 0.01). Without diuretic 1K1C animals decreased GFR and ERPF after ACEI (p less than 0.005, P less than 0.001). In the clamped kidney of 2K1C rats, GFR and ERPF decreased significantly (p less than 0.0005, p less than 0.004) and contralateral kidney ERPF increased (p less than 0.001), but GFR did not. The consequences of ACEI on GFR are similar with or without diuretic. These data suggest that diuretic therapy may not significantly interfere with ACEI evaluation of renovascular hypertension.

Animals↗
PubMed1992

The Trial of Antihypertensive Interventions and Management (TAIM) study. Adequate weight loss, alone and combined with drug therapy in the treatment of mild hypertension.

This report examines the effect of weight loss, alone and in combination with drugs, on diastolic blood pressure change in the Trial of Antihypertensive Interventions and Management (TAIM), which is a randomized, multicenter, placebo-controlled clinical trial of drug and diet combinations in the treatment of mild hypertension among 787 patients. Diastolic blood pressure drop (11.6 mm Hg) at 6 months among those patients who were randomized to weight reduction and placebo drug treatment was greater among those who lost 4.5 kg or more, than the 7-mm Hg drop for those who lost less than 2.25 kg or for the placebo-treated control group, and it was statistically equivalent to the reduction achieved by 25 mg of chlorthalidone or 50 mg of atenolol (11.1- and 12.4-mm Hg drop, respectively). Weight loss potentiated effects of drugs, with reductions of 18.4 mm Hg, for those patients who were taking atenolol and had a 4.5-kg or more weight loss, and of 15.4 mm Hg, for those patients who were taking chlorthalidone and had at least a 2.25-kg weight loss. We concluded that effective weight loss (greater than or equal to 4.5 kg) lowers blood pressure similarly to low-dose drug therapy and potentiates drug effects, with the apparent 4.5-kg threshold being lowered to 2.25 kg for those patients who receive chlorthalidone.

Atenolol↗
PubMed1991

Effect of antihypertensives on sexual function and quality of life: the TAIM Study.

OBJECTIVE: To evaluate treatment of mild hypertension using combinations of diet and low-dose pharmacologic therapies. DESIGN: Multicenter, randomized, placebo-controlled clinical trial. SETTING: Three university-based tertiary care centers. PATIENTS: Patients (697) 21 to 65 years of age with diastolic blood pressure between 90 and 100 mm Hg as well as weight between 110% and 160% of ideal weight. INTERVENTION: Patients were stratified by clinical center and race and were randomly assigned to one of three diets (usual, low-sodium and high-potassium, weight loss) and one of three agents (placebo, chlorthalidone, and atenolol). MEASUREMENTS: Changes in measures of sexual problems, distress, and well-being after 6 months of therapy were analyzed. MAIN RESULTS: Low-dose chlorthalidone and atenolol produced few side effects, except in men. Erection-related problems worsened in 28% (95% CI, 15% to 41%) of men receiving chlorthalidone and usual diet compared with 3% (CI, 0% to 9%) of those receiving placebo and usual diet (P = 0.009) and 11% (CI, 2% to 20%) of those receiving atenolol and usual diet (P greater than 0.05). The weight loss diet ameliorated this effect. The low-sodium diet with placebo was associated with greater fatigue (34%; CI, 23% to 45%) than was either usual diet (18%; CI, 10% to 27%; P = 0.04) or weight reduction (15%; CI, 7% to 23%; P = 0.009). The low-sodium diet with chlorthalidone increased problems with sleep (32%; CI, 22% to 42%) compared with chlorthalidone and usual diet (16%; CI, 8% to 24%; P = 0.04). The weight loss diet benefited quality of life most, reducing total physical complaints (P less than 0.001) and increasing satisfaction with health (P less than 0.001). Total physical complaints decreased in 57% to 76% of patients depending on drug and diet group, and were markedly decreased by weight loss. CONCLUSION: In general, low-dose antihypertensive drug therapy (with chlorthalidone or atenolol) improves rather than impairs the quality of life; however, chlorthalidone with usual diet increases sexual problems in men.

Adult↗
PubMed1991

The role and rationale of nuclear medicine procedures in the differential diagnosis of renovascular hypertension.

The use of radionuclides in the differential diagnosis of renovascular hypertension has gone through many periods of enthusiasm and of disappointment. Regardless of the problems with the routine renogram, the availability of gamma camera renal evaluation makes possible meaningful preintervention of screening. The use of the test as a follow-up procedure is an extremely important but often overlooked application of radionuclides in the evaluation of renovascular hypertension. The radionuclide technique is a sensitive and accurate method of evaluating the results of percutaneous angioplasty or surgery or renal function in the affected kidney of patients with renovascular disease. A major change in our approach to the nuclear medicine diagnosis of renovascular hypertension has been the introduction of captopril renography. Although there is still a great deal of work to be done and many investigators are actively studying captopril renography, the potential of the test is clear. Captopril renography should include a baseline renogram, followed by the administration of 25 mg of captopril and a repeat study. Specificity and sensitivity data on this test probably will not be available for several years, but preliminary results are encouraging enough to justify routine use at this time in clinics in which screening for renovascular hypertension is carried out.

Diagnosis, Differential↗
PubMed1991

Captopril renography. Considerations in the selection of radiopharmaceuticals, provocative agents, and hypertensive subjects.

Captopril renography is an excellent technique for investigating renovascular hypertension and other renal disturbances. However, many variables affect the usefulness of renographic data. The choices of radiopharmaceutical, converting enzyme inhibitor, and the type of imaging done must be made with care. Additionally, the method for selecting a study population must be carefully examined. Incorrect choices can render a study's data valueless. In this paper we delineate the questions that need to be considered before undertaking a renographic study.

Captopril↗
PubMed1991

The Einstein/Cornell collaborative protocol to assess efficacy and methodology in captopril scintirenography. Early results in patients with essential hypertension. Report of the Einstein/Cornell Collaborative Hypertension Group.

We have established an ongoing prospective investigation of hypertensive patients to examine the rates of false results in captopril scintirenography. This study is being conducted at the Albert Einstein College of Medicine and the Cornell University Medical Center. Two large populations will allow an accurate assessment of both false positive and false negative results. We report here the results from the first 30 patients, results which will be useful in defining the bounds for future studies.

Adult↗
PubMed1991

Report of the Working Party Group on Determining the Radionuclide of Choice.

There are a variety of radiopharmaceuticals that can be used to perform captopril renography effectively. We examined a number of technetium and iodine compounds and the circumstances under which each radiopharmaceutical compound is the compound of choice. Considerations of cost, ease of use, reliability, dosage, and the effects of different protocols were all examined.

Captopril↗
PubMed1991

Procedures of choice in renal nuclear medicine.

The uronephrologic applications of nuclear medicine have reached a stage of maturity where procedures of choice for many specific clinical problems can be identified. This review attempts to achieve this aim as objectively as possible. It must be emphasized that the opinions expressed here are those of the author and in many areas there may be a lack of consensus.

Humans↗
PubMed1990

Pharmacologic and nutritional treatment of mild hypertension: changes in cardiovascular risk status.

OBJECTIVE: To evaluate the 6-month change in cardiovascular (coronary heart disease) risk as a function of diet and drug therapy for mild hypertension. DESIGN: Collaborative randomized, controlled clinical trial to assess the efficacy of alternative regimens in treating mild hypertension. SETTING: Three university-based tertiary care centers-the Trial of Antihypertensive Interventions and Management (TAIM). PATIENTS: Six hundred and ninety-two men and women ages 21 to 65 years with diastolic blood pressure between 90 and 100 mm Hg and weight between 110% and 160% of ideal weight. MEASUREMENTS AND MAIN RESULTS: Patients stratified by clinical center and race were randomized into diet (usual, low sodium-high potassium, weight loss) and drug (placebo, chlorthalidone, and atenolol) groups resulting in nine diet plus drug combinations. The cardiovascular risk at 6-month follow-up was estimated relative to baseline in 692 participants using the Framingham Study model. Due to the blood pressure reduction, cardiovascular risk declined from baseline for all treatment groups (except the usual diet plus chlorthalidone group because of increased cholesterol levels). The relative cardiovascular risk at 6 months compared to baseline ranged from 0.83 in the weight loss plus atenolol subgroup to 1.03 in the usual diet plus chlorthalidone subgroup. The active drug plus weight loss groups showed the lowest relative cardiovascular risk at 6 months. CONCLUSIONS: Mild hypertension was generally reduced to desirable levels within 6 months by monotherapy. Evaluating blood pressure changes together with the risk factors indicated a differential effect on overall cardiovascular risk depending on the diet and drug used. Dietary therapy, particularly weight reduction, was important adjunctive treatment in reducing overall cardiovascular risk.

Adrenergic beta-Antagonists↗