Search PubMed⌕ Search

Biomedical subjects

E D Bennett

Publications and source records attributed to E D Bennett.

90 records · Page 5Linked to original sources
PubMed1984

Increased forearm vascular resistance after dopamine blockade.

The peripheral haemodynamic effects of a 40 mg intravenous injection of domperidone (a dopamine antagonist) have been studied in 10 normal subjects. In four subjects domperidone was infused directly into the brachial artery and the effects on forearm blood flow were measured. When administered systemically, domperidone significantly decreased forearm blood flow by 9% (P less than 0.01) and significantly increased calculated forearm vascular resistance by 11% (P less than 0.01). The drug produced no measurable changes in forearm blood flow at any dose when infused directly into the brachial artery. A further study was carried out into the effects of a systemic injection of domperidone on peripheral sympathetic tone. Reduction of sympathetic tone in the forearm was achieved by passively raising the legs of eight recumbent subjects. Before domperidone administration, passive leg elevation significantly increased forearm blood flow by 39% and decreased forearm vascular resistance by 13%. After drug administration the absolute values of vascular resistance increased and the changes between the supine and elevated position values when compared with those of the corresponding values prior to drug administration were significantly lower. These results suggest that the role of domperidone in increasing peripheral vascular tone is unlikely to be mediated by a direct local effect on peripheral resistance vessels. Any effect the drug may have is suggested to be mediated via a central control mechanism.

Adult↗
PubMed1982

Abolition, by dopamine blockade, of the natriuretic response produced by lower-body positive pressure.

1. In a preliminary study, a positive pressure of 25 mmHg applied to the lower body raised right atrial pressure by a mean of 7 mmHg. 2. Sustained application of lower-body positive pressure (LBPP) in six normal adult males increased sodium excretion ([Na]V) from a control level of 126.5 +/- 10 mumol/min to 213 +/- 21 mumol/min (P = 0.003) and fractional sodium excretion (EfNa) from 0.7 +/- 0.1 to 1.2 +/- 0.1 (P = 0.001). 3. Urine flow (UF) increased from 0.85 +/- 0.07 ml/min to 4.1 +/- 0.8 ml/min (P = 0.002), osmolar clearance (Cosm) from 2.6 +/- 0.13 ml/min to 4.2 +/- 0.4 ml/min (P = 0.003) and free water clearance (CH2O) from -1.75 +/- 0.1 ml/min to -0.1 +/- 0.01 ml/min (P = 0.001). Creatinine clearance (Ccr) showed no significant change. 4. After dopamine blockade with domperidone, LBPP did not cause a rise in [Na]V or EfNa. However, urine flow, Cosm. and CH2O remained significantly above control values, implying persistent suppression of antidiuretic hormone. 5. Dopamine blockade without positive pressure did not affect basal sodium excretion.

Adolescent↗
PubMed1980

Changes in red cell deformability and other haemorrheological variables after myocardial infarction.

Haemorrheological variables were studied in 43 patients after acute myocardial infarction. Red cell deformability, by a filtration method, was significantly lower within 12 hours of infarction than subsequently. This drop was greater in the presence of haemodynamic complications. Blood viscosity, particularly when adjusted to a standard haematocrit, rose in the week after infarction, as did plasma viscosity and plasma fibrinogen. Haematocrit, however, fell over this period. These changes could increase myocardial ischaemia and lead to extension of the area of infarction.

Adult↗
PubMed1979

Effect of glyceryl trinitrate on echocardiographic left ventricular dimensions during exercise in the upright position.

Changes in left ventricular size may be of importance in the development of angina and in its amelioration by glyceryl trinitrate, but left ventricular dimensions have not been measured during exercise in the upright position, the circumstance in which angina most often occurs. To assess changes in left ventricular end-systolic and end-diastolic dimensions, echocardiograms were obtained from 5 normal subjects and 6 patients with angina during rest and exercise upright, both before and after glyceryl trinitrate. The end-systolic dimension was considered an index of regional performance rather than an estimate of overall left ventricular behaviour. During exercise the end-diastolic dimension rose both in the normal subjects and in the patients. The end-systolic dimension fell progressively with exercise in the normal subjects but changed inconsistently in the patients. Glyceryl trinitrate lowered the end-diastolic dimension during exercise below comparable pretreatment values in both groups; the glyceryl trinitrate-induced decrease in end-diastolic dimension in the patients diminished at higher exercise levels. In all normal subjects and in 4 of the 6 patients with normal systolic shortening (= end-diastolic--end-systolic dimension) glyceryl trinitrate caused relatively small changes in the end-systolic dimension and systolic shortening on exercise. In contrast, in the 2 patients with hypokinetic ventricles glyceryl trinitrate conspicuously decreased the end-systolic dimension and increased systolic shortening. Thus, during exercise, in the normal subjects and in the patients with normally functioning left ventricles on echocardiography, glyceryl trinitrate caused a modest fall in the end-diastolic dimension and little change in the end-systolic dimension, but in patients with ventricular hypokinesia it greatly improved regional contractile performance. Alleviation of ischaemic hypokinesia during exercise may be an important part of the benefit of glyceryl trinitrate.

Adult↗
PubMed1976

Pulmonary oedema in meningococcal meningitis.

Two cases of meningococcal meningitis complicated by pulmonary oedema are described. The pulmonary arterial wedge pressure was raised in the one case studied. Profound sympathetic over-activity may be the cause of the pulmonary oedema occurring in this situation. If this is so, adrenergic blockade would appear to be a rational approach to therapy.

Adult↗
PubMedDate not supplied

Intravascular oxygenation with the IVOX.

Improvements in hollow fibre gas transfer membranes have enabled the development of an intravascular oxygenator which for the first time provides gas exchange without the need for an extracorporeal circuit. We describe all aspects of the clinical utilization of the intravascular oxygenator device.

Animals↗
PubMedDate not supplied

Independent evaluation of the California Tobacco Education Program.

OBJECTIVE: To monitor the implementation of tobacco control programs and research in accordance with California's Proposition 99, approved by the voters in 1988, which increased the state's cigarette tax by 25 cents and designated one quarter of the increased revenue-approximately $100 million per year-to develop statewide media campaigns and to fund local health departments, community-based organizations, schools, and agencies working with high risk populations. METHODS: The authors evaluated the extent and the effectiveness of the implementation independently with standardized forms developed to track any tobacco-related information and activities, local media campaigns, changes in local policies and ordinances, training sessions, and prevention and cessation programs. Activities were reported on the forms to the authors monthly or quarterly. RESULTS: The evaluation indicated that local health departments, community-based organizations, and other group produced an exceedingly high volume of diverse tobacco control activities throughout the state. They reached a variety of ethnic groups and high risk populations with their programs. The data also show that local health departments and competitive grantees responded with an overall shift in their approach to tobacco control and moved from interventions focused primarily on individual people to broader, more community- and environment-oriented interventions. Additionally, analysis of the wholesale tobacco tax revenues revealed that per capita purchasing continued to decline in California at a rate greater than in the rest of the United States. CONCLUSION: The evaluation demonstrated that Proposition 99 accomplished much of what it set out to do-reducing tobacco prevalence, reaching out to underserved populations, and heightening the awareness of the dangers of environmental tobacco smoke.

Adolescent↗