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Biomedical subjects

D K Lowe

Publications and source records attributed to D K Lowe.

26 records · Page 2Linked to original sources
PubMed1978

Disseminated varicella complicating ulcerative colitis.

Disseminated varicella is an uncommon complication of ulcerative colitis, despite the frequent use of steroid therapy in this disorder. Fatal varicella infection occurred in a patient with ulcerative colitis who was receiving steroid therapy. This observation suggests that zoster-immunoglobulin should be administered to patients exposed to varicella with ulcerative colitis who are receiving steroid therapy.

Adolescent↗
PubMed1978

Myocardial blood flow as measured by fractional uptake of rubidium-84 and microspheres.

Under conditions of varying flow rates, total myocardial blood flow, measured by fractional uptake of rubidium-84, using a coincidence counting system, was compared with myocardial flow measured by microspheres (15 +/- 5 micrometer). The methods were compared, open-chested, in 47 dogs: 17 during control, ten following 5 min of ligation of left anterior descending coronary artery, five following i.v. isoproterenol, six following ligation and isoproterenol, and nine after ligation plus dipyridamole. Regional flows by Rb-84 and by either Ce-141 or Cr-51 microspheres were also compared for left ventricle, as well as for nonischemic posterior wall, which served as a reference area, and for anterior wall with ligation of left anterior descending artery in the same preparations. There were no significant differences in total or regional flow measured by the two methods, nor in the estimate of ischemic area size. The data indicate that measurement of myocardial blood flow by fractional uptake of a potassium analog is a reliable method in the presence of ischemia and drug intervention. It is suggested that the inequalities of extraction ratio that occur with differing flow rates do not invalidate fractional-uptake methods over the flow ranges examined.

Animals↗
PubMed1975

Myocardial blood flow response to isometric (handgrip) and treadmill exercise in coronary artery disease.

Thirty patients undergoing coronary cineangiography for diagnosis or evaluation of coronary artery disease had myocardial blood flow studies pre and post handgrip (isometric) exercise just prior to cineangiography. The handgrip was maintained at one-third maximum effort for three minutes. The patients also had treadmill exercise testing a day or two prior to the study. Treadmill testing was carried out until angina or positive ST-segment changes occurred or the patient attained 90% of predicted maximal heart rate. Of the 30 patients, seven had no coronary artery disease and 23 had significant disease, i.e., greater than 75% occlusion of at least one major coronary artery. Six of the 23 patients (26%) with disease had angina with handgrip and demonstrated a decreased myocardial blood flow, a significantly different response from the patients without agina (P less than 0.001). For the group without angina, the blood flow response was not significantly different from the normal group. Treadmill tests were positive in 19 of the 23 patients with coronary disease (83%). The arterial systolic and diastolic pressure rise was almost identical with the two stresses. The heart rate response, however, was significantly different (P less than 0.001), the rate increase being greater with treadmill exercise. The myocardial blood flow data demonstrate the relative insensitivity of handgrip exercise for the diagnosis of coronary artery disease. In terms of the supply demand ratio (diastolic pressure time/systolic pressure time) concept for subendocardial perfusion, it is possible that the difference between handgrip and treadmill stress may be due to the different heart rate response, more rapid heart rates having a relatively greater effect on diastolic than on systolic time indices, all other factors being equal.

Angina Pectoris↗
PubMedDate not supplied

Safety and metabolic effects of L-glutamine administration in humans.

A series of dose-response studies was conducted to evaluate the clinical safety, pharmacokinetics, and metabolic effects of L-glutamine administered to humans. Initial studies in normal individuals evaluated the short-term response to oral loads of glutamine at doses of 0, 0.1, and 0.3 g/kg. A dose-related increase in blood glutamine occurred after oral loading and elevation of amino acids known to be end products of glutamine metabolism occurred (including alanine, citrulline, and arginine). No evidence of clinical toxicity or generation of toxic metabolites (ammonia and glutamate) was observed. Glutamine was infused intravenously in normal subjects over 4 hr at doses of 0.0125 and 0.025 g/kg/hr. In addition, glutamine was evaluated as a component of parenteral nutrition solutions (0.285 and 0.570 g/kg/day) administered for 5 days to normal subjects. Intravenous administration of glutamine was well tolerated without untoward clinical or biochemical effects. Subsequent studies in patients receiving glutamine-enriched parenteral nutrition for several weeks confirmed the clinical safety of this approach in a catabolic patient population. In addition, nitrogen retention appeared to be enhanced when glutamine was administered at a dose of 0.570 g/kg/day in a balanced nutritional solution providing adequate calories (145% of basal) and protein (1.5 g/kg/day). Nitrogen balance in patients receiving lower doses of glutamine (0.285 g/kg/day) was similar to that in patients receiving standard formulations. Further controlled clinical trials of the metabolic efficacy, tolerance, and dose response of glutamine in other patient groups are necessary to determine the appropriate use of glutamine enrichment of nutrient solutions.

Administration, Oral↗