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Biomedical subjects

C Fairchild

Publications and source records attributed to C Fairchild.

28 records · Page 2Linked to original sources

Relationships among the TRH, REM latency, and dexamethasone suppression tests: preliminary findings.

The DST and TRH stimulation test (TRHST) were administered to 68 depressed in- and outpatients; 28 subjects also received 2 nights of sleep EEG. Results indicated that (1) the TRHST differentiated RDC endogenous from nonendogenous unipolar subtypes at the 5 but not the 7 IuU/ml threshold, (2) neither order nor timing of DST and TRHST testing affected TRHST response, (3) the TRHST detected subjects not identified by the DST, and (4) REM latency detected some patients (23%) not identified by either the TRHST or DST.

Ambulatory Care↗

Renin classification for diuretic and beta-blocker treatment of black hypertensive patients.

Renin classification has been proposed to guide initial treatment of hypertensive patients with diuretics vs beta-blockers. Most previous studies evaluating this issue have utilized patient populations that were white or predominantly white. Black hypertensives have been noted to differ from white hypertensives in several respects. To evaluate the clinical utility of renin classification in black hypertensives, we compared the blood pressure response of low vs normal renin patients during double-blind treatment with either hydrochlorothiazide or beta blocker (metoprolol or oxprenolol). Hydrochlorothiazide a significantly (P less than 0.05-0.01) larger blood pressure fall than beta-blocker, though there was no difference in the response of low vs normal renin patients. Thus, renin classification does not appear to guide initial selection of diuretic vs beta blocker therapy of black hypertensives, and diuretic therapy is more effective.

Adrenergic beta-Antagonists↗

The effect of dosage on the dexamethasone suppression test in normal controls.

A sample of 23 drug-free, normal adult subjects, aged 23 to 50 years, received 1 mg dexamethasone p.o. at midnight. Serum cortisols were obtained at 0800h, 1600h, and 2330h pre- and postdexamethasone. Only 1 of these 23 subjects (4.3%) evidenced nonsuppression, as defined by any postdexamethasone serum cortisol value of greater than 4.0 micrograms/dl. A dose of 0.75 mg dexamethasone was administered to 23 drug-free, normal adult subjects, 20 of whom participated in the above 1 mg trial. Six of these 23 (26.1%) showed nonsuppression at a threshold of 4.0 micrograms/dl. Another 11 normal adults who were taking various prescription medications (e.g., sympathomimetics, nasal decongestants, birth control pills, thyroid hormones) or who were suffering from untreated upper respiratory infections, venereal infections, or allergies were tested with 1 mg of dexamethasone. In this sample, 7 of 13 (53.8%) showed nonsuppression. These findings suggest that: (1) 1 mg of dexamethasone is the lowest effective dose that can be used in diagnostic testing for melancholic depression; (2) a false-positive response to the dexamethasone suppression test (DST) may occur with infections, allergies, or possibly with certain prescription medications. Further studies of the effects of illness and/or medications on DST responses are needed.

Adult↗

Effect of guanabenz and hydrochlorothiazide on blood pressure and plasma renin activity.

Patients with mild to moderate essential hypertension were treated with guanabenz plus placebo (26 patients) or guanabenz plus hydrochlorothiazide (26 patients) for one year. Ambulatory plasma renin activity was determined during placebo treatment, after four weeks and one year of treatment with the study drugs, and one month after discontinuation of guanabenz while continuing the same hydrochlorothiazide dosage. Treatment with guanabenz plus hydrochlorothiazide proved more satisfactory than treatment with guanabenz plus placebo in that fewer patients were treatment failures, a smaller dosage of guanabenz was required, better control of supine blood pressure was achieved, and no increase in guanabenz dosage was needed to maintain chronic blood pressure control. Drowsiness, dry mouth, and dizziness were the side effects noted most commonly. Plasma renin activity was not significantly suppressed by chronic guanabenz therapy. Thus, guanabenz is an effective new antihypertensive that provides optimal blood pressure control when used with a diuretic.

Adult↗

Role of renin classification for diuretic treatment of black hypertensive patients.

Previous studies in white and mixed-race hypertensive patient populations have generally found patients with low renin activity more responsive to diuretic therapy than patients with normal renin activity. Twenty-nine black patients (26 women and three men) with placebo diastolic blood pressure of 90 to 115 mm Hg were treated with spironolactone (100 to 400 mg/day) and hydrochlorothiazide (100/mg/day). Renin status was categorized by (1) the intravenous furosemide test, (2) ambulation during placebo, and (3) ambulation during spironolactone and hydrochlorothiazide treatment. Only seven patients were categorized identically with all methods. No method identified a low renin subgroup that was more responsive to either spironolactone or hydrochlorothiazide. Diastolic blood pressure fall with hydrochlorothiazide (18 mm Hg) and 400 mg/day of spironolactone (15 mm Hg) was similar. Thus, since black women with both low and normal renin activity are quite responsive to diuretics, renin classification to guide initial antihypertensive selection is not warranted.

Adult↗

Withdrawal syndrome following cessation of guanabenz therapy.

A withdrawal syndrome consisting of nervousness, palpitations, diaphoresis, and insomnia appeared in three patients within 16--48 hours following discontinuation of guanabenz, a new centrally acting antihypertensive agent. A similar syndrome of sympathetic overactivity has been described with abrupt withdrawal of clonidine. Three of four patients treated with 48 mg/day but none of 20 other patients treated with 32 mg/day or less guanabenz developed this syndrome. None of the three patients developed hypertensive crisis, though one had a modest rise in the blood pressure above baseline levels. It is concluded that guanabenz therapy should not be discontinued abruptly and that, when possible, the dosage should be limited to less than 48 mg/day.

Adult↗

Alprazolam in bipolar-I depressions.

In an open-label study of alprazolam in five bipolar-I depressed patients, three patients remitted completely, one failed to respond, and one responded transiently, based on the Hamilton Rating Scale and Beck Depression Inventory scores. Further studies of alprazolam as an antidepressant are warranted.

Adult↗

Further evaluation of saline infusion for the diagnosis of primary aldosteronism.

Normal subjects, normal-renin hypertensive patients, and low-renin hypertensive patients were evaluated by intravenous saline infusion and with a fludrocortisone acetate (Florinef) protocol to clarify diagnostic criteria for primary aldosteronism that are recommended for the saline infusion protocol. The patients consumed a 200 mEq sodium, 70 mEq potassium diet for 6 days, and on the last 3 days received Florinef 0.5 mg orally twice daily. On Days 3 and 6, urinary aldosterone and tetrahydroaldosterone excretions were determined, and on Days 4 and 7 plasma aldosterone (PA) was determined at 0600 after overnight recumbency and at 0800 after 2 hours of walking. Although the level of normal PA suppression by saline infusion has been commonly defined as 10 ng/dl, a value of 5 ng/dl was originally recommended. In 20 normal subjects and 45 normal-renin hypertensive patients, we found that the PA was almost always suppressed below 5 ng/dl. In 18 of 75 low-renin patients including five with aldosterone-producing adenoma (APA), the PA was never suppressed below 10 ng/dl; thus, these 18 patients had classical primary aldosteronism by generally accepted criteria. The Florinef protocol was performed in eight of these 18 patients and was abnormal in all. An abnormal Florinef protocol was also found in seven of 15 patients studied with PA suppression after saline infusion to between 5 and 10 ng/dl, but in only one of 24 patients studied with PA suppression below 5 ng/dl. Additional studies in the subgroup with abnormal results from the Florinef protocol indicated that none of these patients had evidence of APA, so they had nontumorous primary aldosteronism (NTPA).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗