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Biomedical subjects

H Weiner

Publications and source records attributed to H Weiner.

At least 181 records · Page 10Linked to original sources
PubMed1984

Is there a relationship between eating disorder and affective disorder? New evidence from sleep recordings.

There is evidence that patients with anorexia nervosa (particularly those who also have bulimia) and patients with affective disorder share many features. The authors present sleep polygraph data from 20 young women with anorexia nervosa (17 also bulimic) and 10 age-matched normal women. Their urinary free cortisol levels were determined, and the subjects with eating disorders were also rated for depression. The findings suggest the existence of a subgroup of patients who show sleep abnormalities, in addition to clinical and possibly endocrine abnormalities, that indicate concurrent affective disorder. The authors present several models that could account for this relationship.

Adult↗
PubMed1984

Ischemic pseudomembranous colitis with perforation due to polyarteritis nodosa.

Polyarteritis nodosa is a multisystem disease that involves the gastrointestinal tract in more than 50% of patients at some time during its course. Clinically apparent ischemic disease of the small bowel is the frequent site of involvement. The colon is less commonly involved, particularly as the initial presentation. We present a patient with polyarteritis nodosa noteworthy for prolonged nonbloody diarrhea, ischemic colitis with perforation, and pseudomembrane formation who had histological documentation of polyarteritis nodosa.

Colon↗
PubMed1983

Effect of ethanol on synaptosomal (Na+ + K+)-ATPase in control and ethanol-dependent rats.

Rats were made dependent upon ethanol by feeding them liquid diets containing ethanol. Synaptosomal plasma membranes (SPM) were isolated from cerebral cortex and midbrain regions of isocaloric-fed control and ethanol-dependent rats. No major alcohol-induced alteration in in vitro (Na+ + K+)-ATPase activity was found in SPM of either brain area. At 37 degrees C, ethanol (0.10 to 0.98 M) added to incubations caused a dose-dependent inhibition of (Na+ + K+)-ATPase activity. The degree of inhibition found was independent of the diet administered or whether ethanol was present in the diet. At temperatures between 14 and 22 degrees C, 0.48 M ethanol caused a temperature-dependent decrease in activity. Arrhenius plots for SPM (Na+ + K+)-ATPase showed that in control and ethanol-dependent rats fed the Lieber de Carli diet, 0.48 M ethanol did not alter the transition temperature of this enzyme. Activation energies both above and below the transition temperature were decreased by the addition of ethanol to incubations. These results indicate that (Na+ + K+)-ATPase, a membrane-bound enzyme that is sensitive to its lipid environment and to the presence of ethanol, is not altered by the chronic administration of ethanol to rats.

Alcoholism↗
PubMed1983

Effects of magnesium and calcium on mitochondrial and cytosolic liver aldehyde dehydrogenases.

The effects of Mg2+ and Ca2+ ions on the activities of mitochondrial and cytosolic aldehyde dehydrogenases isolated from horse, rat, and beef livers were investigated in 0.1 M sodium phosphate, pH 7.5, at 25 degrees C. As with the Mg2+-enhancement of the horse liver mitochondrial enzyme [17], Mg2+-activation was observed for the mitochondrial enzymes from rat and beef. The cytosolic enzymes from horse, rat, and beef livers were inhibited in the presence of Mg2+ ions. The effects of Ca2+ ions on the activity were essentially the same as those observed in the presence of Mg2+ ions; the mitochondrial isozymes were activated while the cytosolic isozymes were inhibited. The fact that only the activity of mitochondrial forms of mammalian liver aldehyde dehydrogenase was enhanced by Ca2+ or Mg2+ ions may be related to the in vivo regulation of aldehyde metabolism, a presumed mitochondrial event.

Aldehyde Dehydrogenase↗
PubMed1983

Oxidation of acetaldehyde and presence of aldehyde dehydrogenase in rat erythrocytes.

Rat liver erythrocytes were found to oxidize acetaldehyde at 7 nmoles/min/ml blood at 37 degrees C. This is less than 1% the rate that occurs in liver. An aldehyde dehydrogenase was isolated from erythrocytes, but was not purified. The enzyme had a Km of 170 microM toward acetaldehyde at pH 7.4. The enzyme, which could oxidize both aliphatic and aromatic aldehydes, was more active at pH 9 than at 7. Disulfiram proved to be both an in vivo and in vitro inhibitor of the enzyme. Due to the low total capacity of the erythrocytes to metabolize acetaldehyde, it is doubtful they perform any important role in ethanol metabolism.

Acetaldehyde↗
PubMed1981

Effects of pH on horse liver aldehyde dehydrogenase: alterations in metal ion activation, number of functioning active sites, and hydrolysis of the acyl intermediate.

The reactivity of the mitochondrial (pI = 5) isoenzyme of horse liver aldehyde dehydrogenase was determined by studying the effects of pH on steady-state velocity, burst magnitude, and molecular weight of the enzyme in the absence and presence of Mg2+ ions. The Mg2+ ion activation of the steady-state velocity at pH 7.5 has been explained through a mechanism involving alteration of the tetrameric enzyme, functioning with half-of-the-sites reactivity, to a dimeric enzyme, functioning with all-of-the-sites reactivity [Takahashi, K., & Weiner, H. (1980) J. Biol. Chem. 255, 8206-8209]. With increasing pH, the tetrameric enzyme dissociated even in the absence of Mg2+ ions to the more active dimeric state. The pH-dependent dissociation was governed by proton release from a group with pK = 9.5. After correcting for the increased number of functioning active sites, determined from the pre-steady-state burst, we calculated that elevated pH also caused an increase in the velocity of the rate-limiting step, hydrolysis of the acyl-enzyme intermediate. This event was governed by the ionization of two groups, with pK = 7.2 and 9.5, respectively. If these groups are directly involved in the catalytic step, a mechanism involving histidine acting as a general base can be proposed for the former group. The latter group may be involved in a charge relay activation process which only occurs at elevated, nonphysiological pH. The importance of the latter is questionable, as there is only a 3-fold increase in Vmax when this group is involved in catalysis.

Aldehyde Dehydrogenase↗