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Biomedical subjects

W R Davis

Publications and source records attributed to W R Davis.

At least 37 records · Page 2Linked to original sources
PubMed1989

Cerebral function and preservation during cardiac arrest.

Neurologic impairment remains a serious consequence of cardiac arrest. While current investigations are difficult to compare due to their lack of standardization, our understanding of the pathophysiology of CNS ischemia has been greatly increased. Ion fluxes, especially K and Ca, may contribute to injury by initiating a cascade of events culminating in free fatty acid, prostaglandin, and free radical formation, with their related pathogenetic potential. Treatment measures currently consist of CPR (although disagreement exists as to which form of CPR), standard supportive measures, and attention to intracranial pressure control. There is some experimental evidence to support the use of calcium channel-blockers, phenytoin, prostaglandin inhibitors, and free-radical scavengers or inhibitors; however, no human trials have been performed. Steroids and barbiturates have been investigated in human trials and do not appear to be efficacious in ameliorating CNS injury after cardiac arrest.

Animals↗
PubMed1989

Intravenous nicardipine for the treatment of severe hypertension. A double-blind, placebo-controlled multicenter trial.

A placebo-controlled, double-blind multicenter trial was conducted in 123 patients with severe hypertension to examine the efficacy and safety of intravenously administered nicardipine hydrochloride in controlling blood pressure. Seventy-three patients were initially randomized to receive nicardipine treatment. This group had an initial blood pressure of 213 +/- 3/126 +/- 2 mm Hg. Sixty-seven patients achieved the therapeutic goal (diastolic blood pressure less than or equal to 95 mm Hg; systolic blood pressure less than or equal to 160 mm Hg). Fifty patients were randomized to receive placebo solution. Blood pressure in these patients was 216 +/- 3/125 +/- 2 mm Hg. No patient in this group achieved the therapeutic goal during the "blinded" portion of the study. Forty-four of 49 patients who did not respond to placebo administration responded to subsequent treatment with nicardipine. Patients with end-organ damage were included in the study. These included patients with left ventricular hypertrophy, retinopathy, and renal insufficiency. Patients with and without end-organ damage responded equally well to nicardipine treatment. Serious adverse experiences were infrequent, the most common adverse reaction being headache in 24% of the patients studied.

Dose-Response Relationship, Drug↗
PubMed1986

The value of standardized exercise testing in the noninvasive evaluation of mitral stenosis.

The determination of functional impairment is an important portion of the evaluation of patients with mitral stenosis and frequently is instrumental in the determination to proceed with invasive testing. To test the hypothesis that patients with slowly evolving disability from mitral stenosis frequently do not recognize the degree of their limitations and to determine the utility of formal exercise testing, 24 consecutive patients with pure or predominant mitral stenosis were evaluated for NYHA functional category (NYHA class) by historical determination of functional impairment, echocardiographic mitral valve area (echo MVA), exercise duration, estimated maximum oxygen consumption, and functional aerobic impairment during a symptom-limited Bruce protocol exercise test and multiple catheterization-derived parameters. The data revealed no difference in exercise duration or mitral valve area between NYHA classes, but demonstrated an excellent correlation between exercise duration and severity of mitral valve stenosis determined at cardiac catheterization (cath MVA). This relationship was similar to that of echo MVA to cath MVA and exceeded that of exercise time to any other parameter measured during catheterization. Estimation of maximum oxygen consumption or functional aerobic impairment did not improve the exercise duration to valve area relationship. The data presented thus demonstrate that Bruce protocol exercise testing is a valuable adjunct to other noninvasive tests in the initial evaluation of selected patients with mitral stenosis. By virtue of being easily repeated at low risk, exercise testing may also be useful in long term follow-up of medically treated mitral stenosis patients.

Adult↗
PubMed1984

Aberrant origin of the right ventricular coronary artery: a report of two cases.

Aberrant origin of coronary arteries is a not uncommon entity found on cardiac catheterization, at the time of surgery, and on post mortem examination. We present two cases of origin of a right ventricular (or atypical large conus) branch of the right coronary artery originating from a separate ostium in the right coronary cusp, which to our knowledge has been only rarely previously described. We feel that this may be a relatively frequent coronary varient that has important implications regarding patient assessment and care.

Cardiac Catheterization↗
PubMed1983

Listeria monocytogenes prosthetic valve endocarditis.

Listeria monocytogenes is a rare cause of prosthetic valve endocarditis and in all of the four reported cases has occurred as a late complication. Bacteriologic cure of the infection has been obtained in all reported patients, using a standard regimen of either penicillin or penicillin and an aminoglycoside. The two deaths were associated with Starr-Edwards prostheses in the aortic position and have been attributed to embolic phenomena occurring after bacteriologic sterilization of the infected valve.

Aged↗
PubMed1980

A comparison of the bronchodilator and other responses of children to oral treatment with terbutaline tablet and solution: a bioequivalence study.

Terbutaline tablets and oral solution were tested in 16 subjects between the ages of seven and 15 in a double-blind acute cross-over study. Doses of terbutaline were 2.5, 3.75 or 5.0 mg depending upon the weight of each subject. Both formulations produced significant increases in pulmonary function between 15 minutes and five hours after drug administration as measured by FVC and FEV1. The mean maximal increase in FEV1 was 0.60 liters for the tablet and 0.70 liters for the solution. The mean maximal increase in FVC was 0.53 liters for the tablet and 0.67 for the solution. There were significant increases in heart rate following both tablet and solution. The mean increases were statistically significant between two and five hours after drug administration, ranging from two to nine beats/minute for the tablet and eight to 13 beats/minute for the solution. Terbutaline produced no clinically or statistically significant mean changes in systolic or diastolic blood pressure. The responses to tablet and solution did not differ significantly from each other in any parameter. Terbutaline tablet and oral solution were, therefore, bioequivalent.

Administration, Oral↗
PubMedDate not supplied

The impact of providing incentives for attendance at AIDS prevention sessions.

The research literature on AIDS prevention efforts contains many reports on the impact of intervention sessions. Little information is available, however, on the success of various strategies to recruit clients to attend these sessions. An assessment of the comparative impact of money and other types of incentives on group attendance in two AIDS risk reduction projects, in the Harlem area of New York City and in Cleveland, OH, was undertaken. In both projects, injecting drug users and the sex partners of injecting drug users were recruited to participate in group sessions that focused on the reduction of AIDS risk behaviors. Data on group attendance were analyzed for 838 people in the New York project and 1,168 in the Ohio project. After the projects were underway, attendance incentives at both were changed from money to food coupons or gift certificates. Results indicated that a nonmonetary incentive was associated with a significant decline in group attendance. Concerns regarding paying monetary incentives to injecting drug users are discussed.

Acquired Immunodeficiency Syndrome↗