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Biomedical subjects

Karl B Fields

Publications and source records attributed to Karl B Fields.

5 recordsLinked to original sources

The effect of anabolic steroids on the gastrointestinal system, kidneys, and adrenal glands.

Over the past several decades we have seen an increase in the prevalence of anabolic steroid use by athletes. Because use of anabolic steroids is illicit, much of our knowledge of their side effects is derived from case reports, retrospective studies, or comparisons with studies in other similar patient groups. It has been shown that high-dose anabolic steroids have an effect on lowering high-density lipoprotein, increasing low-density lipoprotein, and increasing the atherogenic-promoting apolipoprotein A. Steroid abuse can also be hepatotoxic, promoting disturbances such as biliary stasis, peliosis hepatis, and even hepatomas, which are all usually reversible upon discontinuation. Suppression of the hypothalamic adrenal axis can also lead to profound adrenal changes that are also reversible with time. Although rare, renal side effects have also been documented, leading to acute renal failure and even Wilms' tumors in isolated cases. Much of our knowledge of these potentially severe but usually limited side effects is confounded by use of combinations of different steroid preparations and by the concomitant use with other substances. Physicians must target their efforts at counseling adolescents and other athletes about the potential harms of androgenic anabolic steroids and the legal options to improve strength and performance.

Adolescent↗

Basic biomechanics of the lower extremity.

This article describes common principles of biomechanics for running, jumping, and kicking. These activities form the basis for much of sports activity. Understanding human movement allows the physician to prescribe appropriate prevention, treatment, and rehabilitation to patients.

Biomechanical Phenomena↗

Hypertension in the athlete.

Athletes with hypertension are frequently encountered in clinical settings and during preparticipation examinations. This common condition merits special attention in athletes, as they have particular physiologic and sport-specific demands. Awareness of the pressor response to both isometric and isotonic exercise is valuable in managing hypertensive athletes. Recommendations regarding physical activity in hypertensive patients and clearance for sports participation among competitive athletes are reviewed. Nonpharmacologic measures and the use of customary antihypertensives in athletes is essential. However, knowledge of side-effect profiles and possible negative effects on exercise tolerance guide appropriate medication choices.

Adolescent↗