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Biomedical subjects

M R Levy

Publications and source records attributed to M R Levy.

At least 19 recordsLinked to original sources
PubMed1984

Do-not-resuscitate orders in a county hospital.

The use of the do-not-resuscitate order has become accepted medical practice. To date, however, no study has been done of how often it is used or factors associated with its use. Reports of all deaths of inpatients occurring during calendar year 1981 at San Bernardino County Medical Center were eligible for study. Retrospective review of the 237 cases indicated that a do-not-resuscitate order had been written for 165 (69.6%) of the patients. Comparison of reports of those for whom such an order had been written with those for whom no order had been written indicated that a do-not-resuscitate order was not associated with age, sex, ethnicity or pay status. Indices of mental clarity, however, were associated with orders not to resuscitate; those patients residing in nursing homes, and not alert and oriented on admission were overrepresented in the group given this order. Primary discharge diagnosis was also associated with such an order, as was an increased duration of hospital stay.

California↗
PubMed1983

Provider continuity and quality of medical care. A retrospective analysis of prenatal and perinatal outcome.

It is often assumed that family physicians are able to provide a higher quality of medical care because of the greater degree of continuity inherent in their practices. The authors attempted to measure the association between continuity and quality of medical care using pregnancy as a tracer condition. Using a retrospective cohort study design, two groups of pregnant women were identified--those cared for in the family practice (FP) centers and those cared for in the obstetric (OB) clinics. Process and outcome of medical care were measured along with patient satisfaction. Provider continuity, as measured by the SECON value, was much higher in the FP group, and was highly correlated with the presence of an "attitudinal contract" between patient and physician. Although not statistically significant, four times as many newborns from the OB group were admitted to the neonatal intensive care unit. FP group newborn weight averaged 220 grams more than the OB group (P less than 0.05). This difference remained after control for covariates. While not reaching statistical significance, patient satisfaction scores tended to be higher for the FP group in two of three categories measured. The results suggest that continuity of care was associated with better patient outcome and satisfaction. Directions for causal interpretation and future research are discussed.

Adult↗
PubMed1977

Enzyme inactivation by a cellular neutral protease: enzyme specificity, effects of ligands on inactivation, and implications for the regulation of enzyme degradation.

A protease from Tetrahymena pyriformis inactivated eight of nine commercially available enzymes tested, including lactate deyhdrogenase, isocitrate dehydrogenase (TPN-specific), glucose-6 phosphate dehydrogenase, D-amino acid oxidase, fumarase, pyruvate kinase, hexokinase, and citrate synthase. Urate oxidase was not inactivated. Inactivation occurred at neutral pH, was prevented by inhibitors of the protease, and followed first order kinetics. In those cases tested, inactivation was enhanced by mercaptoethanol. Most of the enzyme-inactivating activity was due to a protease of molecular weight 25,000 that eluted from DEAE-Sephadex at 0.3 M KCl. A second protease of this molecular weight, which was not retained by the gel, inactivated only isocitrate dehydrogenase and D-amino acid oxidase. These two proteases could also be distinguished by temperature and inhibitor sensitivity. Two other protease peaks obtained by DEAE-Sephadex chromatography had little or no no enzyme inactivating activity, while another attacked only D-amino acid oxidase. At least six of the enzymes could be protected from proteolytic inactivation by various ligands. Isocitrates dehydrogenase was protected by isocitrate, TPN, or TPNH, glucose-6-dehydrogenase by glucose-6-P or TPN, pyruvate kinase by phosphoenolypyruvate or ADP, hexokinase by glucose, and fumarase by a mixture of fumarate and malate. Lactate dehdrogenase was not protected by either of its substrates of coenzymes. Citrate synthase was probably protected by oxalacetate. Our data suggest that the protease or proteases discussed here may participate in the inactivation or degradation of a least some enzymes in Tetrahymena. Since the inactivation occurs at neutral pH, this process could be regulated by variations in the cellular levels of substrates, coenzymes, or allosteric regulators resulting form changes in growth conditions or growth state. Such a mechanism would permit the selective retention of enzymes of metabolically active pathways.

Animals↗
PubMed1975

Synthesis of glycolytic and peroxisomal enzymes in Tetrahymena following a change in culture conditions.

The specific activity of a peroxisomal enzyme, lactate oxidase, and of pyruvate kinase and lactate dehydrogenase, which are not peroxisomal, increased rapidly when shaken cultures of Tetrahymena were transferred to conditions of oxygen restriction and supplemented with glucose. Two other peroxisomal enzymes, catalase and TPN-linked isocitrate dehydrogenase, did not increase substantially, nor did succinate dehydrogenase. The increases were reduced if glucose was not added at the time of transfer, and were prevented by actinomycin D or cycloheximide, but not by chloramphenicol. The results suggest an involvement of peroxisomes in the metabolism of glycolytic endproducts when the availability of oxygen to the cell is limiting.

Alcohol Oxidoreductases↗