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Biomedical subjects

D M Davidson

Publications and source records attributed to D M Davidson.

At least 37 records · Page 2Linked to original sources
PubMed1986

Defective gamma-interferon production in peripheral blood leukocytes of patients with acute tuberculosis.

Production of interferon (IFN)-gamma by peripheral blood leukocytes (PBL) was examined in cultures of unseparated fresh whole blood exposed to phytohemagglutinin (PHA), concanavalin A (Con A), or pokeweed mitogen (PWM). The yield of IFN-gamma was measured by a newly developed immunoradiometric assay. Nine of 14 patients with acute pulmonary tuberculosis (TB) showed a depressed IFN-gamma response to Con A and/or PWM. Only four of these TB patients also showed a depressed IFN-gamma response to PHA. Stimulation of the patients' PBL cultures with PHA in the presence of exogenous interleukin 2 (IL 2) produced normal IFN-gamma yields in all but the most severely depressed patients. PBL cultures of TB patients with defective IFN-gamma production in response to mitogenic lectins also produced less IFN-gamma after stimulation with tuberculin PPD. Although some patients showed a moderate degree of lymphopenia, their OKT4/T8 lymphocyte ratios were mostly normal or close to normal, with the notable exception of one TB patient who has been diagnosed to have the acquired immune deficiency syndrome (AIDS).

Adult↗
PubMed1985

Recovery after cardiac events.

This article describes an interdisciplinary program of cardiac rehabilitation that integrates physical therapy with medical, nursing, nutritional, and psychological assessment and treatment. Hospitalized patients recovering from myocardial infarction or cardiac surgery progress through a seven-level program of physical activity, education, and emotional support. These components of the program continue during their early home period and again are integrated during the active training period. In the active training period, patients participate in support groups and receive nutritional, exercise, and medical education and engage in one hour of exercise three times weekly. In all phases, considerable attention is given to the development of behavioral skills necessary for long-term adherence to healthy life style habits.

Attitude↗
PubMed1984

Family-directed preventive cardiology.

Cardiovascular events continue as the leading cause of death in the United States, despite a decline in recent years. Epidemiological evidence has confirmed that in adults smoking, high blood pressure, hypercholesterolemia, a family history of atherosclerotic disease at an early age, diabetes mellitus, and certain behavioral patterns are associated with a higher risk for myocardial infarction and other manifestations of coronary artery occlusion. In addition, a lack of regular physical activity, being overweight, and excess ethanol consumption are associated with increased cardiac disease rates. Since these indicators of risk may appear in childhood, and the earliest manifestations of atherosclerosis or hypertension can become manifest soon thereafter, the prevention of cardiovascular events must begin early. This paper reviews the evidence for the origins of cardiovascular risk in childhood, and offers recommendations to family physicians to help them provide parents with the proper information, motivation, and skills to teach their children healthy nutritional, exercise, and behavioral patterns.

Adolescent↗
PubMed1983

Propionibacterium shunt nephritis in two adolescents with medulloblastoma.

The anaerobic diphtheroid Propionibacterium acnes was identified as the organism responsible for "shunt" nephritis in two adolescents with ventriculoatrial shunts inserted previously for the management of medulloblastoma. Only three cases of "shunt" nephritis secondary to infection with this common skin commensal organism are known to have been reported. The rarity of such reports may be related to the lack of good anaerobic laboratories, the length of time necessary for cultures to show growth, the poor ability of certain blood culture media to support growth of this organism, and the failure of physicians to consider Propionibacterium acnes as a true pathogen in certain clinical situations.

Adolescent↗
PubMed1982

The effect of a standardized psychological stressor on the cardiovascular response to physical effort soon after uncomplicated myocardial infarction.

To determine whether a standardized psychological stressor combined with physical stress might disclose ischemic abnormalities not evident with physical stress alone, 30 men, mean age 54, were evaluated seven weeks after clinically uncomplicated myocardial infarction. In the first 20 patients, two symptom-limited treadmill tests (TM) were performed on the same day, with and without superimposed psychological quiz (Q). In the next 10 consecutive patients, the Q was administered at a submaximal level (4 METs). When TM and TM + Q responses were compared, no significant differences were noted in the maximal levels of heart rate (HR), systolic blood pressure (SBP), rate pressure product, or in the prevalence of ischemic ST segment depression or angina pectoris. The HR and double product at which ischemic ST segment depression and angina pectoris appeared were similar for the two types of testing. The psychological stress of a psychological quiz may not, of course, approximate the effect of the more severe stressors individuals may encounter in their daily routines.

Arrhythmias, Cardiac↗
PubMed1982

Autonomic contribution to heart rate recovery from exercise in humans.

To assess the contribution of the autonomic nervous system to heart rate recovery following exertion, heart rate was observed after peak treadmill exercise in six men following parasympathetic blockade (PB) with atropine sulfate (0.03 mg/kg), sympathetic blockade (SB) with propranolol hydrochloride (0.20 mg/kg), double blockade (DB) with both drugs, and no drugs (ND). Least-squares analysis of each subject's heart rate (HR) as an exponential function of recovery time (t) was computed for each treatment giving an equation of the form HR = aebt. HRs at rest, peak exercise, and 10 min of recovery, the coefficients a and b, and the least-squares correlation coefficient (r) were compared among treatments by nonparametric analysis of variance and rank-sum multiple comparisons. HR recovered in an exponential manner after dynamic exercise in each subject with each of the treatment modes (P less than 0.01 for each r, mean across all treatments r = 0.94). Coefficients a and b differed the most between PB and SB. At the cessation of exercise the decreases in venous return and the systemic need for cardiac output are accompanied by an exponential HR decline. The exponential character of the cardiodeceleration seen after peak exercise appears to be an intrinsic property of the circulation because it occurred under each experimental condition.

Adult↗
PubMed1980

The work evaluation of the cardiac patient.

Treadmill exercise testing performed three weeks following clinically uncomplicated myocardial infarction was used to assess the occupational work potential of 196 men aged 70 or less. Within the six months after infarction the rate of combined medical and surgical events (sudden death, nonfatal cardiac arrest, myocardial infarction or coronary artery bypass graft surgery) was 34% in the one-quarter of patients judged to be at high risk and 4% in the three-quarters of patients judged to be at low risk on the basis of exercise testing--an eight-fold difference. Seven weeks or more after infarction, treadmill testing or leg-cranking ergometry proved more sensitive than static effort or arm cranking or treadmill exercise combined with static effort in the detection of ischemic and arrhythmic abnormalities. Occupational work assessment may limit costs for postinfarction patients in two ways: (1) by facilitating optimal usage of diagnostic tests and therapeutic interventions in high-risk patients; and (2) by obviating needless delay in the return to work of low-risk patients.

Disability Evaluation↗