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Biomedical subjects

K Matthews

Publications and source records attributed to K Matthews.

82 records · Page 5Linked to original sources
PubMed1985

Desmopressin and bleeding time in patients with cirrhosis.

Desmopressin acetate 0.3 microgram/kg was given intravenously to nine patients with chronic liver disease and to a further six such patients in a double blind controlled study versus placebo. Desmopressin acetate significantly shortened the bleeding time compared with basal values in both groups and compared with placebo. There was also a significant decrease in partial thromboplastin time (but not prothrombin time) and significant increases in factor VIII and its components, von Willebrand factor and ristocetin cofactor activity, but not in factors VII, IX, X, XI, or XII. Increased fibrinolysis could be blocked by concomitant administration of tranexamic acid. No important side effects were seen. The multimer pattern of von Willebrand factor was studied for the first time in chronic liver disease. It was normal, but after administration of desmopressin acetate the percentage of multimers of higher molecular weight increased significantly. This may be an important mechanism in the shortening of the bleeding time in cirrhosis, as has been shown in uraemia and other conditions after administration of desmopressin acetate. Desmopressin acetate may be useful in correcting defects in primary haemostasis in chronic liver disease.

Bleeding Time↗
PubMed1985

Occupational noise exposure, noise-induced hearing loss, and the epidemiology of high blood pressure.

The role of noise exposure in the etiology of high blood pressure is unclear. A cross-sectional study of occupational noise exposure and high blood pressure was conducted in March 1981-August 1982 in a group of blue-collar workers from a noisy (greater than or equal to 89 dBA) and a less noisy plant (less than 81 dBA). There were 197 randomly sampled men from the noisier plant and 169 from the comparison factory. Clinical examinations, audiograms and a psychologic inventory were conducted. Body mass index, alcohol intake, and family history of hypertension were comparable for the two groups. There was no difference in mean systolic or diastolic blood pressure between workers in the two plants. There was, however, a strong relationship between severe noise-induced hearing loss (greater than or equal to 65 dBA loss at 3, 4, or 6 k Hz) and high blood pressure (greater than or equal to 90 mmHg diastolic or taking blood pressure medication) in the 56+ age group in both plants after adjusting for risk factors (p less than 0.02). Multiple regression analysis revealed that in the noisier plant, body mass index, severe noise-induced hearing loss, and noisy hobbies explained a significant amount of the variation in diastolic pressure (p less than 0.05) R2 = 0.19. This suggests that there may be a population at increased risk for hearing loss and high blood pressure.

Adult↗
PubMed1977

Osmotic opening of the blood-brain barrier in the rhesus monkey without measurable brain edema.

The blood-brain barrier in the rhesus monkey was opened to intravascular Evans blue-albumin, without causing brain edema or altering brain electrolytes, by perfusing 2.5 molal recrystallized D,L-lactamide into the internal carotid artery for 20--30 sec. Gross neurological and behavioral sequelae were absent in 7 of 8 animals with barrier opening, and 2 days after perfusion no statistically significant changes were observed in sodium, potassium or water contents of perfused as compared to unperfused gray and white matters of brains of the 7 normal animals. Brain endema may not have developed because parenchymal albumin was excreted or metabolized by 2 days. It is suggested also that closure of the barrier after several hours prevents salt from accompanying plasma fluid into the brain. Entry of fluid without salt would reduce, before measurable edema developed, any transcapillary osmotic gradient established by prior entry of plasma albumin.

Animals↗
PubMedDate not supplied

Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat.

OBJECTIVE: Excessive central fat puts one at greater risk of disease. In animal studies, stress-induced cortisol secretion has been shown to increase central fat. The objective of this study was to assess whether women with central fat distribution (as indicated by a high waist-to-hip ratio [WHR]), across a range of body mass indexes, display consistently heightened cortisol reactivity to repeated laboratory stressors. METHODS: Fifty-nine healthy premenopausal women, 30 with a high WHR and 29 with a low WHR, were exposed to consecutive laboratory sessions over 4 days (three stress sessions and one rest session). During these sessions, cortisol and psychological responses were assessed. RESULTS: Women with a high WHR evaluated the laboratory challenges as more threatening, performed more poorly on them, and reported more chronic stress. These women secreted significantly more cortisol during the first stress session than women with a low WHR. Furthermore, lean women with a high WHR lacked habituation to stress in that they continued to secrete significantly more cortisol in response to now familiar challenges (days 2 and 3) than lean women with a low WHR. CONCLUSIONS: Central fat distribution is related to greater psychological vulnerability to stress and cortisol reactivity. This may be especially true among lean women, who did not habituate to repeated stress. The current cross-sectional findings support the hypothesis that stress-induced cortisol secretion may contribute to central fat and demonstrate a link between psychological stress and risk for disease.

Adaptation, Psychological↗
PubMedDate not supplied

Effects of exercise training on cardiovascular function and plasma lipid, lipoprotein, and apolipoprotein concentrations in premenopausal and postmenopausal women.

This study examined the effects of aerobic exercise on lipid levels in premenopausal and postmenopausal women. Fifty healthy middle-aged women (mean age, 50 years) were randomly assigned to 12 weeks of either aerobic exercise (walking and jogging) or nonaerobic strength exercise (circuit Nautilus training). Concentrations of total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, and very low density lipoprotein cholesterol were assessed, along with apolipoprotein (apo) A-I, apo A-II, apo B, and triglycerides. To document changes in aerobic capacity, maximum treadmill testing was performed with expired-gas analysis before and after the exercise program. Aerobic exercise was associated with an 18% improvement in peak VO2. Women in the aerobic group had an increased VO2, from 26.7 to 31.4 ml/kg/min (p less than 0.0001), while the VO2 of the women in the strength training group did not change (25.8 ml/kg/min before and after). There were no differential changes in lipid levels because all subjects experienced slight reductions in high density lipoprotein cholesterol and total cholesterol and increases in apo A-I and the apo A-I to apo B ratio. There was a tendency for the aerobic group to exhibit lower levels of apo A-II and a greater apo A-I to apo A-II ratio, however. We conclude that premenopausal and postmenopausal women experience similar changes in aerobic capacity and lipid levels with exercise and that the short-term effects of aerobic and nonaerobic exercise on lipid profiles are generally comparable.

Analysis of Variance↗