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Biomedical subjects

B Clark

Publications and source records attributed to B Clark.

25 records · Page 2Linked to original sources
PubMed1976

Indications for beta-adrenoceptor blocking drugs in hypertension.

The past 10 years have firmly established the role of beta-adrenoceptor blocking agents in the treatment of hypertension. They have been shown to lower systolic and diastolic blood pressure in the lying and standing position in mild, moderate and severe hypertension. Precise indications for beta-blockade have not yet been completely defined. Some authorities regard them as the drug of first choice in the management of most grades of idiopathic hypertension. There are in addition certain situations where beta-blockade seems especially suitable. These include the presence of associated coronary heart disease manifest either as angina pectoris or dysrhythmia. These agents can be introduced when side effects from other drugs are severe or intolerable and are valuable in the management of hypertensive young males since beta-blocking drugs do not interfere with sexual function. Compared with normotensive subjects 'stress' has been shown to produce excessive rise of blood pressure in those with labile or sustained idiopathic hypertension. After therapy with beta-blocking agents the rise in blood pressure after 'stress' is reduced. If labile and/or mild hypertension are the precursors of subsequently more severe sustained hypertension, then long term beta-blockade may help to control this response.

Adrenergic beta-Antagonists↗
PubMed1975

Tissue concentrations of mercury after chronic dosing of squirrel monkeys with thiomersal.

Squirrel monkeys were dosed intranasally with saline or thiomersal (sodium ethylmercurithiosalicylate, 0.002 percent w/v) daily for six months. The total amounts of thiomersal given during the six months period were 418 mug (low dose group) and 2280 mug (high dose group). This was equivalent to 207 and 1125 mug mercury. The dose differential was achieved by more frequent administration to the high dose group. Mercury concentrations were significantly raised over control values in brain (high dose group only), liver, muscle and kidney, but not in blood. Concentrations were highest in the kidney, moderate in liver and lowest in brain and muscle. Much of the mercury was present in the inorganic form (37-91 percent). No evidence of toxicity due to thiomersal was seen in any animal. Nevertheless accumulation of mercury from chronic use of thiomersal-preserved medicines is viewed as a potential health hazard for man.

Animals↗
PubMed1975

Choice reaction time to visual motion during prolonged rotary motion in airline pilots.

Thirteen airline pilots were studied to determine the effect of preceding rotary accelerations on the choice reaction time to the horizontal acceleration of a vertical line on a cathode-ray tube. On each trial, one of three levels of ratary and visual acceleration was presented with the ratary stimulus preceding the visual by one of seven periods. The two accelerations were always equal and were presented in the same or opposite directions. The reaction time was found to increase with increases in the time the rotary acceleration preceded the visual acceleration, and to decrease with increased levels of visual and rotary acceleration. The reaction time was found to be shorter when the accelerations were in the same direction than when they were in opposite directions. These results suggest that these findings are a special case of general effect that the authors have termed "gyrovisual modulation."

Acceleration↗