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Biomedical subjects

C M Smith

Publications and source records attributed to C M Smith.

At least 289 records · Page 16Linked to original sources
PubMed1979

Erythrocytic ecdysis. An unusual morphologic finding in a case of sickle cell anemia with intercurrent cold-agglutinin syndrome.

Examination of peripheral blood smears from a patient with sickle cell disease during crisis associated with an upper respiratory tract infection, pneumonia, a positive Coombs test, and an elevated cold agglutinin titer revealed unique abnormalities associated with her erythrocytes, which have not been reported previously. In addition to the usual changes in peripheral blood occurring during crisis in sickle cell anemia, large numbers of free, filamentous forms that appeared to be derived from erythrocytes were present on repeated Wright's-stained smears. Erythrocytes were markedly distorted and had single and multiple surface protrusions that appeared to be antecedents of the free filamentous forms. Scanning electron microscopy confirmed the marked changes in the erythrocytes and revealed membrane alterations not apparent by use of the light microscope. It is suggested that the membrane stripping observed in this case was due to cold agglutinin--complement-mediated surface injury superimposed on the known abnormalities of the membranes of sickle erythrocytes.

Agglutinins↗
PubMed1979

Activities of NAD-specific and NADP-specific isocitrate dehydrogenases in rat-liver mitochondria. Studies with D-threo-alpha-methylisocitrate.

The contributions of NAD-specific and NADP-specific isocitrate dehydrogenases to isocitrate oxidation in isolated intact rat liver mitochondria were examined using DL-threo-alpha-methylisocitrate (3-hydroxy-1,2,3-butanetricarboxylate) to specifically inhibit flux through NADP-specific isocitrate dehydrogenase. Under a range of conditions tested with respiring mitochondria, the rate of isocitrate oxidation was decreased by about 20--40% by inhibition of NADP-isocitrate dehydrogenase, and matrix NADP became more oxidized. (a) For mitochondria incubated with externally added DL-isocitrate and citrate, the rate of isocitrate oxidation obtained by extrapolation to infinite alpha-methylisocitrate concentration was approximately 70% of the uninhibited rate in both state 3 and state 4. (b) With pyruvate plus malate added as substrates of citric acid cycle oxidation and isocitrate generated intramitochondrially, a concentration of alpha-methylisocitrate (400 microM) sufficient for 99.99% inhibition of NADP-isocitrate dehydrogenase inhibited isocitrate oxidation in states 4 and 3 by 21 +/- 6% and 19 +/- 11% (mean +/- SEM), respectively. (c) With externally added isocitrate and citrate, the addition of NH4Cl increased isocitrate oxidation by 3--4-fold, decreased NADPH levels by 30--40% and 2-oxoglutarate accumulation by about 40%. The further addition of 600 microM alpha-methylisocitrate decreased the NH4Cl-stimulated isocitrate oxidation by about 40% and decreased NADPH to about 30% of the level prevailing in the absence of NH4Cl; nevertheless, the rate of isocitrate oxidation was still twice as large in the presence of NH4Cl and alpha-methylisocitrate as in their absence. Experiments were also performed with intact mitochondria incubated with respiratory inhibitors to determine additional factors which might affect the flux through the two isocitrate dehydrogenases. (a) In the coupled reduction of acetoacetate by isocitrate, where the rate of reoxidation of reduced pyridine nucleotides is limited by NAD-specific 3-hydroxybutyrate dehydrogenase, 85--100% of the rate of 3-hydroxybutyrate formation was retained in the presence of 400--900 microM alpha-methylisocitrate. (b) In a system where the rate of isocitrate oxidation is limited by the rate of NADPH reoxidation by glutathione reductase, the rate of glutathione reduction extrapolated to infinite alpha-methylisocitrate concentration was from 20--40% of the uninhibited rate. (c) In the coupled synthesis of glutamate from isocitrate and NH4Cl, where the reoxidation of NADPH and NADH can occur via glutamate dehydrogenase, the rate of glutamate production extrapolated to infinite alpha-methylisocitrate concentration was about 60% of the uninhibited rate.

Ammonium Chloride↗
PubMed1979

Relationships among purine nucleoside metabolism, adenosine triphosphate catabolism, and glycolysis in human erythrocytes.

In human erythrocytes incubated with both naturally occurring purine nucleosides and with a variety of purine nucleoside analogs, ATP catabolism was accelerated and lactate accumulation was increased. Tubercidin was a particularly potent inducer of ATP catabolism. In cells incubated with tubercidin, the major route of adenylate metabolism was deamination, whereas in cells incubated with deoxyglucose, the major pathway was dephosphorylation.

Adenosine Deaminase Inhibitors↗
PubMed1979

From hospital to community: a system changes.

Interest in the community and institutional aspects of mental health care in Saskatchewan goes back to the early history of the province, but it is the last 15--20 years which have seen the most exciting developments. During this time the province has changed from having one of the highest mental institutionalization rates in the world to one of the lowest. One mental hospital was phased out and the other reduced to a shadow of its former self. An account of the changes which occurred during this period is given together with the story of the stresses generated. Finally, a 1979 perspective is offered on the Saskatchewan psychiatric program.

Community Mental Health Services↗
PubMed1979

Micellar properties of 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oyl taurine and relationship to in vitro red cell disruption.

Patients with a metabolic block in the conversion of THCA to cholic acid develop cirrhosis and hemolysis. Tauro-THCA has been shown to distort hepatic architecture and cause hemolysis in bile-fistula rats. In this study, the critical micellular concentration of tauro-THCA was found to be one fourth of that measured for the primary human bile salt, taurocholate. In short-term incubations with intact red cells, tauro-THCA was more effective than taurocholate in removing red cell membrane lipid, inducing morphological red cell sphering, and decreasing functional cellular membrane surface area. These detergent biological membrane effects were most apparent at a concentration above the critical micellar concentration, with the membrane toxicity of the two bile salts roughly paralleling their differences in critical micellar concentration. The lower critical micellar concentration, greater hydrophobicity, and enhanced surface-active properties of tauro-THCA are speculated on as possible factors contributing to the bile salt's toxicity in vivo.

Animals↗
PubMed1979

Transient myeloid metaplasia associated with an unusual hemoglobin in a newborn infant.

A newborn infant presented with hepatosplenomegaly, rash, anemia, and leukocytosis at one day of age and manifested characteristic myeloid metaplasia by one mouth of life. Vitamin B12 and leukocyte alkaline phosphatase were elevated and platelet aggregation was impaired. Myelofibrosis was not present and neutrophil function was preserved. An unidentified high isoelectric point hemoglobin with unusual chromatographic and electrophoretic behaviors was found to comprise 12% of the total hemoglobin. The myeloid metaplasia and mutant hemoglobin disappeared over the subsequent months without biochemical or clinical residual. The available evidence was consistent with the mutant hemoglobin representing either a gamma chain or clonal embryonic chain variant. The inability to clarify prognostic factors in these unusual myeloproliferative syndromes suggests caution in the initiation of cytotoxic therapy.

Electrophoresis, Cellulose Acetate↗
PubMed1978

Sclerodermatous graft-versus-host disease limited to an area of measles exanthem.

A female patient with severe idiopathic aplastic anaemia received a successful bone-marrow transplant from her HLA-identical, mixed-lymphocyte-culture-compatible, brother. 8 months after transplantation she had localised cutaneous measles. Chronic sclerodermatous changes developed which were indistinguishable from chronic graft-versus-host disease and were limited to the areas of the original exanthem. Interaction between viral infection and minor histocompatibility differences probably resulted in graft-versus-host disease in this patient.

Adolescent↗
PubMed1978

Possible biochemical basis of memory disorder in Alzheimer disease.

Damage to the hippocampal formation, whether focal or diffuse, leads to severe impairment of short-term memory. The most common presenting symptom of Alzheimer disease is loss of short-term memory, and histologically the hippocampus is characteristically affected. Choline acetyltransferase, which is involved in the synthesis of acetylcholine, is depleted in the hippocampus in the disorder. Anticholinergic drugs administered to normal subjects can simulate some aspects of the memory defect seen in Alzheimer disease. It is postulated that damage to a cholinergic neuronal pathway running to or from the hippocampus underlies the memory disorder. This suggestion implies that it may be possible to improve memory in patients with Alzheimer disease by pharmacological means.

Acetylcholine↗