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Biomedical subjects

A Ward

Publications and source records attributed to A Ward.

At least 199 records · Page 11Linked to original sources
PubMed1983

Amrinone. A preliminary review of its pharmacological properties and therapeutic use.

Amrinone is a bipyridine derivative with positive inotropic effects and vasodilatory properties. However, in the clinical setting of congestive heart failure, the relative contribution of these factors remains a matter of conjecture. Its mode of action appears to be related to alterations in extracellular and intracellular calcium balance, probably mediated by increased levels of tissue cyclic adenosine monophosphate and possibly involving a sodium-dependent pathway. Clinical experience has mostly been short term and is limited to a relatively small number of patients with severe congestive heart failure, refractory to conventional treatment. Amrinone rapidly improves cardiac performance by decreasing systemic vascular resistance (afterload), decreasing the determinants of left ventricular filling pressure (preload) and improving the cardiac contractility. Improvements in exercise performance and clinical symptomatology occur without an increase in heart rate or decrease in mean arterial pressure. Amrinone has been compared with dopamine, dobutamine, pirbuterol and prazosin in preliminary short terms studies in patients with severe congestive heart failure, although more studies are needed before any relative clinical advantages or disadvantages can be ascribed to amrinone. Initial experience suggests that the addition of vasodilators such as hydralazine and isosorbide dinitrate to amrinone therapy may confer additional haemodynamic benefits. Preliminary medium term studies suggest that tolerance to the haemodynamic effects of amrinone does not usually occur, but long term studies are needed to determine whether amrinone alters the normal progression of the disease and whether overall mortality is affected. Amrinone has usually been administered as intravenous bolus doses (totalling 1.5 to 3.6 mg/kg/day) and/or continuous intravenous infusion, with varied results. Generally, an oral dose greater than the intravenous dose is required to achieve an equivalent level of response. Reversible, usually asymptomatic, thrombocytopenia occurs in about 20% of patients treated with amrinone. Arrhythmias and gastrointestinal disturbances have been reported, but wider clinical experience is required to determine the side effect profile of the drug.

Absorption↗
PubMed1983

Access of the black urban elderly to medical care.

Access to medical care of 492 black urban respondents 60 years of age and older was measured in a house-to-house survey in a large midwestern city. Of those in this study, 93 percent indicated that they had a regular source of medical care, and 88 percent reported a visit to a physician or clinic within the past year. These percentages are higher than those reported for the general population of elderly people in the United States. Physical limitation, general health, and mental health were related to access to medical care. Respondents who reported poorer physical and mental health were more likely to have a regular source of care and to have seen a physician in the past year.

Black or African American↗
PubMed1982

Comparative analysis of physiologic responses to three different maximal graded exercise test protocols in healthy women.

The purpose of this study was to compare the three most commonly used maximal graded exercise test (GXT) protocols in healthy women. Submaximal and maximal metabolic and hemodynamic responses were determined from two treadmill protocols, Bruce and Balke, and a bicycle protocol, in 49 women. Maximum oxygen uptake (VO2 max) was significantly different among protocols (Bruce=40.3, Balke=38.4, and Bike=36.6 ml/kg . min -1). Maximum heart rate (HR max) was significantly lower during Bike (178 beats/min) than during Bruce (182) and Balke (183) protocols. No differences in rate of increase in HR or systolic blood pressure (BP) per increase in multiples of the rest metabolic (METs) were found between Bruce and Balke protocols. The rate of recovery of HR and systolic BP was not different among tests. Comparisons of active and sedentary groups showed differences in VO2 max and submaximal HR and recovery HR at common minutes; however, the rate of increase in HR and systolic BP during exercise and the rate of decrease during recovery were not significantly different. Prediction of VO2 max with Bruce and Balke protocols from treadmill time was r=0.91 (SEE +/- 2.7 ml/kg . min -1) and r=0.94 (SEE 2.2 ml/kg . min -1), respectively. These data suggest a difference between men and women in increased HR and systolic BP per METs increase in exertion.

Adipose Tissue↗
PubMed1982

Propranolol absorption in untreated coeliac disease.

1. To compare the bioavailability and the elimination of propranolol in seven untreated coeliac patients and six normal subjects, plasma concentrations were measured after oral and intravenous propranolol. The bioavailability and clearance of propranolol were similar in both groups. 2. With the use of a perfusion technique, propranolol absorption in the proximal jejunum was found to be decreased by 71% in five untreated coeliac patients, compared with the absorption in four normal subjects. 3. There results indicate that propranolol absorption is decreased in the proximal jejunum in untreated coeliac disease but overall absorption in the small bowel is not impaired.

Absorption↗
PubMed1981

Chemotherapy responsiveness of human tumors as first transplant generation xenografts in the normal mouse: six-day subrenal capsule assay.

Feasibility of utilizing human tumors as first transplant generation xenografts in the normal immunocompetent mouse for determining tumor sensitivity to chemotherapeutic agents was demonstrated by applying subrenal capsule (SRC) assay methodology to fresh surgical explants in a six-day time frame. A total of 37 human breast tumors were tested in assays in which 254 xenografts were implanted into control animals. Fifty (20%) of the controls showed some degree of partial regression in the six-day assay period. Using a mean control growth having a positive change in tumor size as the criterion for evaluability, first transplant generation human breast tumors provided an evaluable assay rate of 86%. A tumor response profile was obtained as a result of testing seven clinically active drugs against 32 previously untreated breast cancers. The pattern of responses obtained indicated that no single agent was active against all tumors, nor were tumors which were responsive to one agent necessarily responsive to another, suggesting the feasibility of predicting individual tumor response to specific chemotherapeutic agents. Had these seven drugs been developmental agents of unknown activity which were being tested for the first time against such a panel of human tumors the result would have not only predicted their clinical activity, but the tumor response rates would have also provided an indication of the relative potential of each drug for the specific treatment of breast cancer.

Adenocarcinoma↗
PubMed1981

Surgical audit.

Explore the source record for details and available documents.

Data Collection↗
PubMed1980

Distinction between obstructive and atrophic dilatation of ventricles in children.

The computed tomography (CT) scans of 92 infants and children were reviewed. Thirty-three had proven atrophy, and 44 had proven obstructive hydrocephalus. Twelve CT measurements were made, and the results were subjected to computer analysis. The pathologic patients were divided into three groups by ventricular size index: mild (33--39%), moderate (40--46%), and severe (greater than 46%) enlargement. Obstructive patients showed much greater measurements for the temporal horn diameter and the frontal horn radius. The angle of the frontal horn was narrower in the obstructed group than in the atrophic patients. As expected, there were significantly more sulci visualized in the atrophic group than in the obstructed group. Three of these four parameters were directly related to concentric expansion of the ventricles in the presence of obstructive hydrocephalus. This is contrasted with passive dilatation of the ventricular system with preservation of the normal ventricular configuration in atrophy. The temporal horn diameter, frontal horn radius, the angle of the frontal horn, and the number of sulci all distinguish between obstruction and atrophy with individual probabilities of less than 0.05. When used together, they assure a high probability of separating obstruction from atrophy. Preliminary data suggest that these findings may have application in adults, but the number of confirmed observations has been too small for statistical analysis.

Atrophy↗
PubMed1980

Generalized equations for predicting body density of women.

Previous research with women has shown that body composition regression equations derived from anthropometric variables were population specific. This study sought to derive generalized equations for women differing in age and body composition. The hydrostatic method was used to determine body density (BD) and percent fat (%F) on 249 women in 18 to 55 years (X = 31.4 +/- 10.8 yrs) and 4 to 44 %F (X = 24.1 +/-7.2 %F). Skinfold fat (S), gluteal circumference (C) and age were independent variables. The quadratic form of the sum of three, four and seven S in combination with age and gluteal C produced multiple correlations that ranged from 0.842 to 0.867 with standard errors of 3.6 to 3.8 %F. The equations were cross-validated on a different sample of 82 women with similar age and %F characteristics. The correlations between predicted and hydrostatically determined %F ranged from 0.815 to 0.820 with standard errors of 3.7 to 4.0 %F. This study showed that valid generalized body composition equations could be derived for women varying in age and body composition, but care need to be exercised with women over an age of forty.

Adipose Tissue↗
PubMed1979

Mean steady-state plasma concentrations of labetalol in patients undergoing antihypertensive therapy.

1 Mean steady-state plasma concentrations of labetalol (labetalol Css) in 17 hypertensive patients undergoing chronic treatment with this drug, have been examined in relation to dose, fall in BP, and beta-blockade. 2 A significant relationship (rs = 0.81, P less than 0.001) was observed between labetalol Css and daily dose. 3 No correlation was found between labetalol Css and antihypertensive response. 4 In thirteen patients, there seemed to be significant relationship between labetalol Css and beta-blockade (rs = 0.72, P less than 0.005). In three patients, the degree of beta-blockade was disproportionate to the drug concentration.

Adult↗