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Biomedical subjects

A J Schwartz

Publications and source records attributed to A J Schwartz.

At least 19 recordsLinked to original sources
PubMed1995

Replacement therapy with imiglucerase for type 1 Gaucher's disease.

Gaucher's disease, the most common sphingolipidosis, is caused by deficiency of the lysosomal enzyme glucocerebrosidase. Therapy with alglucerase (the placental enzyme) is safe and effective at various dosing regimens. We report the use of low-dose imiglucerase (the recombinant enzyme) at two dosing schedules: 15 u/kg once fortnightly or 2.5 u/kg thrice weekly. Mean reductions in spleen and liver volumes achieved (in all ten patients) by imiglucerase at 12 months were 36.4% and 14.5%, respectively; mean increase in haemoglobin and platelet counts were 13.4% and 25.7%. There were no serious side-effects. No significant differences were observed between the two schedules. Low-dose low-frequency imiglucerase may be an alternative cost-effective approach with satisfactory clinical response and uncompromised quality of life.

Adolescent↗
PubMed1994

Cyclooxygenase inhibitors depress norepinephrine constriction of rat abdominal, but not thoracic, aorta.

Experiments were done on aortic rings (thoracic and abdominal) from young and retired breeder Lewis and Sprague-Dawley male rats. Constriction responses to norepinephrine, 5-hydroxytryptamine (5-HT), and prostaglandin F2 alpha, were done +/- the cyclooxygenase blockers, indomethacin or mefenamic acid. Indomethacin significantly depressed norepinephrine constriction in abdominal (but not thoracic) aorta of all groups. In additional studies of abdominal aorta from Lewis retired breeders, indomethacin and mefenamic acid depressed norepinephrine (but not 5-HT or prostaglandin F2 alpha) construction. Furthermore, indomethacin depressed norepinephrine constriction in vessels denuded of endothelial cells. The thromboxane receptor antagonist SQ 29548 did not alter norepinephrine constriction. Thus, in rat abdominal aorta, norepinephrine constriction is mediated by a constrictor prostanoid of vascular smooth muscle origin that is not thromboxane A2.

Adrenergic alpha-Antagonists↗
PubMed1994

Dirofilaria immitis: depression of endothelium-dependent relaxation of canine femoral artery seen in vivo does not persist in vitro.

In heartworm-infected dogs, circulating filarial factors appear to be responsible for the seasonal depression of endothelium-dependent responses seen in the in vivo femoral artery. The effect of heartworm infection on vascular responses of the femoral artery in vitro, when the vessel is not constantly exposed to circulating factors, is unknown. Experiments were designed to test the hypothesis that in vivo exposure to circulating filarial factors leads to changes in the magnitude and mechanism of endothelium-dependent relaxation that are demonstrable in vitro. Rings of femoral artery from heartworm-infected and noninfected control dogs were suspended in muscle baths, and dose-response relationships to endothelium-dependent (methacholine) and -independent (sodium nitroprusside) vasodilators were done. To determine the mechanism of relaxation, dose-response relationships were also done in the presence of an inhibitor of nitric oxide synthase (L-NAME), an inhibitor of guanylate cyclase (methylene blue), or an inhibitor of cyclooxygenase (mefenamic acid). Heartworm infection did not depress endothelium-dependent relaxation of the femoral artery in vitro. Furthermore, the mechanism of relaxation in heartworm and control femoral artery is identical. These data suggest that the effect of circulating filarial factors that alter the magnitude and mechanism of relaxation in systemic vessels in heartworm-infected dogs rapidly disappears in their absence. This results has important bearing on the dynamics of heartworm-induced pathophysiological changes during infection and could influence the nature and chronology of responses to therapy.

Animals↗
PubMed1994

Perianesthetic considerations for the elderly patient.

The principles that guide the perianesthetic management of the elderly patient are the same as those used for all patients. What makes the care of this group challenging is not learning a new set of principles, but rather understanding the specific application of these guidelines to the unique traits of elderly patients. Only then is it possible to avoid complications that the elderly patient has very little margin of reserve to deal with.

Aged↗
PubMed1987

Levels and causes of stress among residents.

Medical and dental residents at the University of Rochester Medical Center were surveyed to measure stress and its causes. Their stress, as measured by the brief symptom inventory, showed levels slightly above those of an adult comparison group. The average levels of stress decreased with the residents' advancing levels of training. Comparison of the top quartile with the lowest quartile of scores of everyday stress showed significantly elevated stress for rotations in the emergency room, greater frequency of being on call, and lesser amount of sleep. The residents' reports showed that the bleakest three days of residency tended to occur in the first year and during intensive care rotations. Stress during these bleakest times was significantly higher than everyday levels. The residents described the major causes of distress during bleakest times as lack of sleep, inadequate support from senior professionals, large patient load, and competition from peers. "High quality" teaching rounds, a night-float system, and sick leave were felt by the residents to lessen stress. To cope with the stress, the residents reported they talked to others, tried to see humor in the situation, or slept.

Adaptation, Psychological↗
PubMed1983

Hemodynamic predictors of myocardial ischemia during halothane anesthesia for coronary-artery revascularization.

The authors undertook a prospective study of 30 patients undergoing halothane anesthesia for coronary-artery revascularization to ascertain which clinically monitored hemodynamic variables--or combination of variables--associated with myocardial oxygen supply and demand best predict myocardial ischemia. Simultaneous recordings of electrocardiogram (lead II and V5), systemic, central venous, pulmonary artery, and pulmonary artery occluded pressures were analyzed for correlation with ischemic episodes. Ischemia occurred with significant increases (P less than 0.0001) in heart rate, central venous pressure, and pulmonary artery occlusion pressure and with significant decreases (P less than 0.0001) in systolic and mean arterial blood pressure and in coronary perfusion pressure (mean arterial minus pulmonary artery occluded pressure). There was no correlation between ischemia and either hypertension (systolic blood pressures up to 200 mmHg) or the rate-pressure product. Systemic systolic blood pressure, systemic mean arterial blood pressure, and coronary perfusion pressure as single determinants were the most useful to monitor in avoiding myocardial ischemia. A combination of systemic arterial blood pressure (systolic or mean) and filling pressure (central venous or pulmonary artery occluded) was generally as useful but not more so than the preceding single variables in avoiding ischemia. Rate-pressure product was not of value in this regard. Patients were divided into three groups according to preoperative left ventricular (LV) function to determine whether pulmonary artery occluded pressure (PAOP) was more useful than central venous pressure (CVP) as either a predictor of ischemia or an index of cardiac filling: normal LV function (Group I), moderately abnormal LV function (Group II), and markedly abnormal LV function (Group III). PAOP offered no advantage over CVP for either purpose, except in some Group III patients.

Blood Pressure↗