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Biomedical subjects

B K Clark

Publications and source records attributed to B K Clark.

5 recordsLinked to original sources
PubMed1992

Beta-adrenergic blocking agents: their current status.

Use of beta (beta)-adrenergic blocking agents began in the 1960s and has risen dramatically since then. Newer agents offer more actions and fewer side effects. Uses for the drugs continue to increase as their safety and efficacy become increasingly apparent. beta block, today, has widespread application in cardiovascular disease. In addition, these agents are used in the management of endocrine disorders, neurologic situations, psychiatric disorders, gastrointestinal problems, and sensory disorders. Many new beta blockers are still investigational, and some show even greater promise for therapeutic applications in the future.

Adrenergic beta-Antagonists↗
PubMed1988

Predictors of length of hospitalization after cardiac surgery.

The cardiac surgical data base at Georgetown University Hospital was reviewed for patients operated on between January 1, 1980, and September 30, 1986, to determine predictors of length of postoperative hospitalization. Mortality among the 1,919 operations was 115 (6%). In the study group of 1,804 operations resulting in survival for at least 30 days, the following factors were analyzed: type of operation, age, sex, New York Heart Association (NYHA) Functional Class, urgency of operation, preoperative myocardial infarction (MI), weight, body surface area, hypertension, diabetes mellitus, previous cardiac operation, smoking history, and family history of cardiac disease. The overall mean length of hospitalization was 10.7 +/- 5.6 days. The analyses indicated that valve operation, age less than 30 and greater than 60 years, female sex, NYHA Class IV, urgent operation, preoperative MI 1 to 4 weeks before operation, and diabetes mellitus requiring medical treatment prolonged hospitalization, but generally by only 2 days. Major prolongation of hospitalization was associated with age in the 20- to 30-year and 80- to 90-year brackets. Unexpectedly, heavy body weight and smoking were not predictive.

Age Factors↗
PubMed1981

Laboratory and initial clinical studies of nifedipine, a calcium antagonist for improved myocardial preservation.

This report summarizes five years of laboratory investigations and the initial six-month clinical experience with a calcium antagonist, nifedipine, added to a cold hyperkalemic cardioplegic solution for enhancement of myocardial protection. Regional ischemia was created in 112 dogs and global ischemia in 98 dogs, under normothermic and two hyperthermic states. Control solutions, two clinical cardioplegic solutions, and nifedipine solutions were compared. Infusion of nifedipine during regional ischemia and reperfusion intervals resulted in a two-to-threefold reduction in injury volume and maintenance of normal left ventricular function in contrast infusion of nitroprusside. Nifedipine solutions (0.2 microgram/ml) provided superior preservation of left ventricular function in comparison to the two cardioplegic solutions after one hour of global ischemia at 37 degrees C and two hours at 18 C. In a clinical trial of nifedipine in cold potassium cardioplegia, 38 high risk patients with poor ventricular function have been treated; 22 of which were intensively studied serially with radionuclide ventriculography and pyrophosphate scans, myocardial isoenzyme determinations, 24 hour EKG recordings and intra- and postoperative hemodynamic studies. Of the 35 patients admitted to the intensive care unit (ICU), 33 have survived. Stroke work and cardiac indices return promptly to near normal levels after operation. The time-isoenzyme activity curves are low and radionuclide determined ejection fractions show no change for the study group. Death from acute postischemic cardiac failure did not occur in treated patients and the usage of intra-aortic balloon pump (IABP) has decreased threefold in comparison with 40 similar high risk patients treated concurrently with cardioplegic solution alone. It is concluded that nifedipine is a potent adjunct to cold hyperkalemic cardioplegic solution in high risk patients.

Adult↗