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Biomedical subjects

H Williams

Publications and source records attributed to H Williams.

At least 253 records · Page 14Linked to original sources
PubMed1980

Interaction between cigarettes and propranolol in treatment of angina pectoris.

To determine whether cigarette smoking interferes with the medical management of angina pectoris, 10 patients with angina pectoris who smoked at least 10 cigarettes a day were studied before, during, and after a standardised maximal exercise test. This was done at the end of four randomly allocated one-week treatment periods during which the patients took glyceryl trinitrate while not smoking, took glyceryl trinitrate while smoking, took glycerly trinitrate and propranolol (380 mg/day) while not smoking, and took glyceryl trinitrate and propranolol while smoking. Carboxyhaemoglobin was measured to ensure compliance. Smoking was associated with a significantly higher heart rate, blood pressure, number of positions with ST-segment depression, and total ST-segment depression after exercise than non-smoking (p < 0.01) whether or not the patients were taking propranolol. These results suggest that smoking aggravates the simple haemodynamic variables used to assess myocardial oxygen requirements and the exercise-induced precordial electrocardiographic signs of myocardial ischaemia. These effects were still evident after treatment with propranolol and represent a hindrance to the effective medical treatment of angina pectoris.

Adult↗
PubMed1980

Diagnosis of twin zygosity by self-assessment and by genetic analysis.

For 173 pairs of like-sex adult twins, self-assessment of zygosity was verified by laboratory diagnosis. Seventeen percent of twins who were very likely monozygous (MZ) believed themselves dizygous (DZ), frequently citing two placentas at their delivery as "evidence." We suggest that twins be asked what leads them to their assessment of their own zygosity. For 93% of Caucasian and 89% of American Black like-sex twins in our sample, DZ twins could be differentiated based on six polymorphic markers retrievable from frozen sera. MZ twins who believe themselves DZ can be considered "environmentally DZ, genetically MZ" twins, and might be used to study genetic and environmental influences on the treatment of twins and on twins' choices of social characteristics.

Alleles↗
PubMed1980

Toxoplasmosis in farmed red deer (Cervus elaphus) in Scotland.

Farming of red deer began in Scotland in 1970 when an experimental nucleus was established on a hill farm in Kincardineshire. From 1972 to 1977 sera from these animals were tested by the haemagglutination test (HA) and the Sabin-Feldman dye test (DT) for the presence of antibodies to Toxoplasma gondii. Overall, dye test antibodies (greater than or equal to 1/16) were detected in 32.5 per cent of sera and HA antibodies in only 9.8 per cent. On average 14.1 per cent of the deer tested in 1972, 1973 and 1975 were DT positive while a sharp rise to 51.4 per cent was noted in the 1974 animals. These antibody titres were not sustained nor were they reflected by the HA. Marked animals bled serially throughout the survey confirmed the general low level of antibody in the herd and the spasmodic rise in 1974. Experimentally infected deer showed a rise and subsequent fall in DT antibody levels with persistently low HA titres. Since the correlation between HA and DT antibody titres was generally poor the HA would be of limited value in screening for Toxoplasma antibody in farmed red deer sera. The direct agglutination test was used to examine selected sera and the results indicated its potential screening value.

Animals↗
PubMed1979

Renal hemodynamics and the renin--angiotensin system in cirrhosis: relationship to sodium retention.

Renal hemodynamics and the renin-angiotensin-aldosterone system were investigated in 15 cirrhotic patients without renal failure on controlled sodium intake of 140-160 mEq/day and related to the degree of sodium retention as measured by urinary sodium excretion. Fourteen patients were free of clinical ascites when studied. The distribution of renal blood flow was measured by the noninvasive technique of computerized radioisotope renography. In 11 patients, outer cortical renal plasma flow, expressed as a percentage of total effective renal plasma flow, was directly proportional to sodium excretion (P less than or equal to 0.01). Three patients with severe sodium retention (UNa.V less than or equal to 10 mEq) had estimated outer cortical renal plasma flows of less than or equal to 274 ml/min/1.73 M2 as compared to eight cirrhotics with better (UNa.V greater than or equal to 50 mEq) sodium tolerance (mean = 438 ml/min/1.73 M2). A significant inverse correlation (P less than or equal to 0.01) existed between outer renal cortical blood flow and plasma renin activity. No significant relationship was observed between glomerular filtration rate, total effective renal plasma flow, plasma aldosterone concentration and sodium excretion. These results provide further evidence that a renal vascular abnormality exists in cirrhosis, and that diminished outer cortical renal perfusion is related to the elevated renin levels and sodium intolerance observed in cirrhotic patients.

Angiotensin II↗
PubMed1979

The Mamprobi Survey--a screening survey for cardiovascular disease and risk factors in Africa: methodology and validity.

The Mamprobi Survey is a cardiovascular disease prevalence sample survey in an African community in Ghana. This preliminary paper describes its methodology and validity. Response rate corrected for migration from the area was 73%. Subsequent sampling of non-respondents revealed only trivial reasons for non-attendance and only minor differences in health status, suggesting that estimates of disease prevalence by the survey were likely to be accurate.

Adolescent↗
PubMed1979

Identification of benzhydrol as a urinary metabolite of diphenylmethane in the rat.

Liquid-liquid extraction and preparative thin-layer chromatography were used to isolate 30 micromoles of benzhydrol from the beta-glucuronidase treated 24 hour urine of rats administered 5.3 mmoles of diphenylmethane. The benzhydrol was identified by its melting point, elemental analysis, infrared, nuclear magnetic resonance, and mass spectra.

Animals↗