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Biomedical subjects

P S Hall

Publications and source records attributed to P S Hall.

9 recordsLinked to original sources
PubMed1997

Salt and blood pressure responses to calcium antagonism in hypertensive patients.

Since salt intake may affect blood pressure response to antihypertensive drugs, an individual's salt-sensitivity status may be an important consideration in the selection of a medication. The purpose of this single-blind study was to assess the impact of salt sensitivity on the antihypertensive effects of isradipine. A total of 21 evaluable hypertensive patients (10 white, 11 black) 35 to 73 years of age (mean 55.9 years) were randomized to a low-salt diet (mean 24-hour urine sodium 100+/-14 mmol) or a high-salt diet (mean 24-hour urine sodium 210+/-22 mmol) for 7 weeks, followed by crossover to the other diet after a 2-week washout period. On each diet regimen, patients received placebo for 2 weeks, followed by optimal titration of isradipine (2.5 to 10 mg BID) for blood pressure control during the last 5 weeks. On the high-salt diet, salt-sensitive hypertensives (mean arterial blood pressure increase > or = 5 mm Hg, n=5) exhibited a systolic/diastolic blood pressure change of -18.7/-19.6 mm Hg from 157.2/102.9 mm Hg after 5 weeks of isradipine treatment, whereas on a low-salt diet, blood pressure change was -6.9/-12.0 mm Hg from 148.7/97.3 mm Hg. Non-salt-sensitive patients (n=16) exhibited a systolic/diastolic blood pressure change of -12.6/-7.6 mm Hg from 155.3/98.6 mm Hg on the high-salt diet and -19.2/-10.9 mm Hg from 161.0/102.6 mm Hg on the low-salt diet after treatment with isradipine. The absolute blood pressure attained in both salt-sensitive and non-salt-sensitive patients was almost identical with isradipine therapy despite variation in dietary salt, although slightly higher doses of isradipine were required in the salt-sensitive group. Consequently, isradipine, and perhaps calcium antagonists in general, manifests a more robust blood pressure-lowering effect in the setting of high sodium intake. This effect does, however, appear to be largely confined to individuals who are salt sensitive.

Adult↗
PubMed1996

Useful DNA polymorphisms are identified by snapback, a midrepetitive element in Tribolium castaneum.

The red flour bettle, Tribolium castaneum, is both a pest of stored grain products and an important experimental organism. To improve its facility as a genetic model, we are developing DNA fingerprinting methods for this insect. A Tribolium DNA fragment, snapback-1 (SBI), identified among sequences that reassociate before a Cot of 0.03 mol.s/L, was found to produce a banding pattern in restriction endonuclease digested genomic DNA that is characteristic of a midrepetitive element. DNA fingerprints of individual beetles demonstrated that unvarying inherited DNA polymorphism is revealed, and that polymorphism is inherited in a dominant Mendelian fashion. Linkage between bands was minimal. The sequence of SBI was determined, and hybridization experiments indicated that SBI is a fragment of a larger midrepetitive element. Fingerprinting individuals with known inbreeding coefficients indicated that SBI loci have relatively high mutation rates. The possibility that SBI is a fragment of a transposable element is discussed.

Animals↗
PubMed1991

Minimization of indomethacin-induced reduction in renal function by misoprostol.

A prospective, randomized, open-label, triple crossover comparison of the effects of indomethacin, misoprostol, or the combination, on renal function was performed to assess the ability of an oral prostaglandin E analogue, misoprostol, to minimize indomethacin-induced decline in renal function in middle-aged women. Twelve healthy women (mean age: 60.5 +/- 1.6 yr) with normal renal function (serum creatinine: 81 +/- 9 umol/L) were studied; six women were normotensive, and six women were hypertensive with their blood pressure controlled with 50-mg hydrochlorothiazide daily. All patients were placed on a 2-g sodium daily diet for 2 weeks before initiation of the study. The subjects were prospectively randomized to receive each of three 4-day treatments of indomethacin (25 mg q 6hr), misoprostol (200 mcg q 6hr), or the combination of drugs with a 4-day washout between each treatment period. Measurements of GFR (urine accumulation of 99mTc-DTPA) and RPF (serum disappearance 131I-Hippuran), and urine collections for electrolytes were obtained before the first treatment period and on the fourth day of each treatment period. Three of the six hypertensive patients and three of the six normotensive patients had a decrease (greater than 10%) in GFR associated with indomethacin therapy. When misoprostol was given with the indomethacin, four of these six patients did not experience a decline in GFR (baseline GFR for six patients: 75.4 +/- 6.6 mL/min/1.73m2, GFR after indomethacin: 57.8 +/- 9.5 mL/min/1.73m2, GFR with combination of indomethacin and misoprostol: 69.7 +/- 3.5 mL/min/1.73m2. RPF was not consistently altered by subacute/chronic dosing of indomethacin, misoprostol, or the combination of the drugs. The authors conclude that misoprostol ameliorates indomethacin-induced renal dysfunction in salt-restricted and diuretic-treated middle-aged women with normal serum creatinine.

Alprostadil↗
PubMed1988

Simple procedures for comprehensive vision screening.

Visual problems can cause poor academic performance or inappropriate behavior. This article explains simple, easily administered procedures to determine if students have problems with acuity, accommodation, binocularity, or eye movements. The evaluator can use vision screening in conjunction with associated learning or behavior problems to initiate referral to the family vision care specialist.

Accommodation, Ocular↗
PubMedDate not supplied

The relationship between ocular functions and reading achievement.

Students in grades 1 through 6 were assessed on 11 ocular functions. A multivariate correlation was made between these ocular functions and the students' reading ability, as measured on the Stanford Achievement Test. There were no significant multivariate correlations between the ocular functions and the students' reading ability. It was concluded that for students with small heterophorias and no significant refractive errors, a relationship did not exist between ocular functions and reading ability.

Achievement↗
PubMedDate not supplied

Efficacy and tolerability of enalapril and sustained-release verapamil in older patients with mild to moderate essential hypertension.

The study involved 113 patients over age 50 years with mild to moderate essential hypertension, randomly assigned to treatment with enalapril (n = 54) or sustained-release verapamil (n = 59). During an eight-week titration period, doses were adjusted to achieve supine diastolic blood pressures (DBP) below 90 mmHg; patients were then given maintenance doses for eight weeks. Mean blood pressures were reduced significantly from 147.7/93.9 mmHg at baseline to 137.7/84.5 mmHg at the end of the maintenance period in the enalapril group and from 155.1/95.1 to 142.4/86.2 mmHg in the verapamil group. In the patients who completed treatment, the mean daily doses required to maintain DBP below 90 mmHg were 9.6 mg of enalapril and 244.9 mg of verapamil. There were 11 treatment failures in the enalapril group and 22 in the verapamil group: eight of the enalapril and 17 of the verapamil patients did not attain goal blood pressures and three and five were withdrawn because of side effects. It is concluded that both enalapril and sustained-release verapamil were generally effective and well tolerated in the treatment of mild to moderate hypertension in the middle-aged and older patients.

Aged↗
PubMedDate not supplied

Blood pressure and heart rate changes in children when they read aloud in school.

The 52 children in the study were recruited from two fifth grade classes in Baltimore city. The blood pressures and heart rates were recorded both at rest and while they read aloud in a classroom setting. A computerized monitoring system was used to measure blood pressures. Rapid and highly significant increases in blood pressure and heart rate were observed when the children read aloud. A total of 84 measurements of 312 systolic and diastolic readings were not within the 95th percentile of normal pressure for the child's age and sex. The data indicate that a routine school task, that is, reading aloud, may have significant effects on the cardiovascular system. These findings are discussed in terms of previously unexamined links between certain childhood school experiences and potential problems with adult hypertension.

Black People↗