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Biomedical subjects

S A Hussain

Publications and source records attributed to S A Hussain.

At least 19 recordsLinked to original sources
PubMed1996

Relationship of peak exercise capacity with indexes of peripheral muscle vasodilation.

Since leg muscles receive the majority of cardiac output and consume a large proportion of total oxygen consumption (VO2) during cycle exercise, maximum leg blood flow may be an important determinant of peak VO2 (VO2peak). We investigated the relationships between parameters of active hyperemia after thigh tourniquet occlusion (alone or with calf exercise) with whole body peak exercise capacity during maximum cycle exercise. Twenty-one healthy male subjects, aged 19-39 yr. performed maximum incremental cycle exercise. Calf blood flow, conductance (blood flow/mean blood pressure), vasodilatory capacity (peak/baseline conductance), and duration of vasodilation were then determined with venous occlusive plethysmography under two conditions: 1) after thigh tourniquet occlusion for 10 min; 2) after ischemic calf exercise (thigh tourniquet occlusion with calf exercise to exhaustion). Group mean VO2peak was 120 +/- 35% (standard deviation) predicted. There was a significant relationship between VO2peak/ lean body mass and peak calf conductance after maximum ischemic calf exercise (r = 0.556; P < 0.01). However, VO2peak/lean body mass was more closely correlated with the duration of vasodilation after thigh tourniquet occlusion with ischemic calf exercise (r = 0.861; P < 0.001). These results suggest that the duration of calf vasodilation after maximal ischemic calf exercise appears to be a better index of cycle exercise capacity in healthy subjects.

Adult↗
PubMed1995

Protective effects of antioxidants against uraemia-induced lipid peroxidation and glutathione depletion in humans.

The effects of uraemias and antioxidant therapy for 40 days with vitamin A, vitamin C and vitamin E on blood and erythrocyte sulfhydryl (glutathione, GSH) content and on erythrocyte glutathione-S transferase (GST), glutathione reductase (GSR) and glutathione peroxidase activities were studied in six uraemic patients maintained on haemodialysis. In addition, the effect of antioxidant therapy on erythrocyte lipid peroxidation was determined, and erythrocyte haemoglobin content was measured. Uraemic patients in dialysis exhibited significant decreases in blood and erythrocyte GSH content as well as significant decreases in the activities of GST, GSR and GSH-peroxidase relative to control subjects. Furthermore, the uraemic patients had elevated erythrocyte malondialdehyde levels. Blood and erythrocyte GSH content from uraemic patients was significantly elevated after 20 days of antioxidant treatment and remained elevated thereafter throughout the remaining 20 days of the study (130% and 173%, respectively). Antioxidant therapy also produced significant increases in GSR and GSH-peroxidase activities after 20 days of treatment which remained relatively constant thereafter. No significant change in GST activity was observed. Erythrocyte malondialdehyde levels, as an index of oxidative tissue damage, exhibited a significant decrease (70%) in the patients after 40 days of antioxidant therapy. A gradual increase in erythrocyte haemoglobin content was observed following treatment of the uraemic subjects (45% at day 40). The results suggest that antioxidant therapy may protect against oxidative stress associated with uraemia.

Antioxidants↗
PubMed1991

Prediction of airway responsiveness to allergen from skin sensitivity to allergen, airway responsiveness to histamine and serum IgE levels.

Immediate allergic reaction of the skin, non allergic airway responsiveness of the bronchi, and serum IgE levels were estimated in 25 atopic non asthmatic subjects and 15 controls. A good correlation was observed between these three parameters i.e. patients with positive skin response to allergen had increased airway responsiveness and significantly increased levels of serum IgE. However, the serum levels of IgE provided a significantly better indication of the likely presence of bronchial allergic reactivity than did the skin reactivity. The results indicate that knowledge of the airway responsiveness to histamine, skin sensitivity to allergen and serum IgE levels can predict the presence of airways responsiveness to an allergen. In all atopic non asthmatic individuals with a significant correlation between these parameters, the relevant allergen could stand identified as having the potential to provoke attacks of clinical asthma.

Adult↗
PubMed1988

Risk to surgeons: a survey of accidental injuries during operations.

A survey was conducted with the participation of eight consultant general surgeons, two consultant urologists, four consultant orthopaedic surgeons and four surgical residents to find the incidence of accidental injuries to surgeons and their assistants during operations. Of the total of 2016 operations over a one year period there were 112 reported accidental injuries. These included 107 needle stick injuries, 4 knife cuts and 1 diathermy burn. We found that accidental injuries to surgeons during operations were inevitable.

Accidents, Occupational↗
PubMed1988

Effect of age on the pharmacokinetics of coumarin.

Coumarin was administered i.v. to male beagle dogs, ranging in age from 0.33 to 11.08 years. Some of these dogs were used more than once in the study as their ages progressed. When divided into two groups, young (less than 5 years) and elderly (greater than 5 years), the total plasma clearance decreased significantly as a function of age from 30.67 +/- 9.86 ml/min/kg in the young group (n = 7) to 17.31 +/- 4.35 ml/min/kg in the elderly group (n = 10). No significant changes were found in apparent volume of distribution and elimination half-life. Because coumarin is a drug of high extraction ratio, and liver blood flow decreases with age, the reduction in total clearance is blood flow dependent. 7-Hydroxycoumarin, the major metabolite, did not show any change in elimination half-life as function of age. The ratio of AUC parent drug: metabolite increased about 10-fold as function of age, indicating decreased hydroxylation and glucuronidation.

Aging↗
PubMed1988

Transdermal absorption and topical bioavailability of coumarin.

Coumarin was administered I.V., P.O. and topically to male Sprague-Dawley rats. The concentration-time profile after I.V. administration could be best described by an open-two compartment model. After P.O. administration the fraction of drug absorbed was 0.21 +/- 0.08 (S.D.). 1 g of hydrophilic ointment (U.S.P. XIX) containing 5% w/w of coumarin was applied on the shaven back skin. When the area of application was 4.91 cm2 the drug was absorbed in a zero-order fashion. The fraction of administered drug absorbed in 6 h was 0.086 +/- 0.02 (S.D.). Increasing the area of application to 30.0 cm2 resulted in deviation from the zero-order absorption characteristic. This is attributed to decrease in the concentration gradient as more drug is absorbed and to the change in formulation characteristics as a function of time. The fraction of drug absorbed in 24 h was 0.66 +/- 0.21 (S.D.).

Administration, Cutaneous↗