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Biomedical subjects

R L Blake

Publications and source records attributed to R L Blake.

At least 73 records · Page 4Linked to original sources
PubMed1981

After-hours management of febrile children.

During a nine-month period approximately 15 percent of the children less than ten years of age in a university family practice had an after-hours medical contact for a febrile illness. Children less than two years of age accounted for 55 percent of the encounters. The most frequent diagnoses were upper respiratory tract infection, acute otitis media, and undifferentiated fever. Slightly less than one half of the children were seen by the on-call resident, and age and level of fever did not correlate with the likelihood of being seen. Very few of the children had a white blood cell count obtained, and none had a blood culture or lumbar puncture. In this practice, after-hours management of the febrile infant differed substantially from guidelines in the literature based on experiences in university emergency rooms and walk-in clinics.

Child↗
PubMed1977

Cytochrome c oxidase activity in T/t6 (balanced lethal) mutant mice.

R-1 (1450g) and R-2 (25,000g) liver fractions from T/t6 and B6CBAF1 hybrid mice were analyzed for their protein content, mitochondria concentrations, and activities of three respiratory-chain enzymes of the mitochondrial inner membrane: cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase, E.C. 1.9.3.1.), alpha-glycerophosphate dehydrogenase [L-glycerol-3-phosphate: (acceptor) oxidoreductase, E.C. 1.1.99.5], and succinate-cytochrome c reductase. Only cytochrome c oxidase activity, calculated as units per 10(10) mitochondria, was significantly lower in both R-1 and R-2 fractions of T/t6 mice. Cytochrome c oxidase activity varied greatly among T/t6 mice, as did their liver mitochondria concentrations and body weights. Cytochrome c oxidase activity in the R-1 fraction of T/t6 mice, averaged about 40% lower than in B6CBAF1 mice. alpha-Glycerophosphate dehydrogenase activity was often elevated in T/t6 mice, particularly in the R-2 fraction. The T/t locus, a complex genetic locus on chromosome 17, may contain genes important to the function and biogenesis of mitochondria.

Age Factors↗
PubMed1976

Altered polyamine metabolism in the PRO/Re strain of inbred mice.

The PRO/Re strain of inbred mice are characterized by abnormally high concentrations of proline in both blood (hyperprolinaemia) and urine (prolinuria). They excrete increased amounts of polyamines in their urine. Male PRO/Re mice excreted putrescine at 175% and spermidine at 300% the amount of male C57BL/6J controls. Female PRO/Re mice excreted putrescine at 115% and spermidine at 150% of the amount in the urine of female controls. Examination of the enzymes involved in polyamine biosynthesis revealed that ornithine decarboxylase, the initial enzyme in the polyamine-biosynthetic pathway, was increased by 150% in the kidneys and by 100% in the liver of male PRO/Re mice. There was no significant difference between PRO/Re and C57BL/6J male mice for either putrescine- or spermidine-stimulated S-adenosylmethionine decarboxylase activity. Female PRO/Re mice showed no significant difference from female C57BL/6J mice for any of the enzymes examined. When the concentrations of the polyamines in the tissues of the PRO/Re mice were determined, spermidine and spermine concentrations in the kidneys of the male PRO/Re mice were twice those of the controls. Spermidine concentration in the livers of both male and female PRO/Re mice was approx. 130% that of the controls. Polyamine concentrations in the brains were similar in controls and mutants. The increased polyamine biosynthesis and excretion in the PRO/Re mutant mice may be a mechanism to decrease the extent of proline accumulation.

Adenosylmethionine Decarboxylase↗
PubMed1976

Mitochondrial proline dehydrogenase deficiency in hyperprolinemic PRO/Re mice: genetic and enzymatic analyses.

Genetic analyses, involving backcross and F2 matings, demonstrate that the type I hyperprolinemia of PRO/Re mice is caused by an abnormal allelet at a single locus designated pro-1. Mice homozygous for this allele (pro-1b/pro-1b) posses a deficiency in the activity of component 1 of mitochondrial proline dehydrogenase. In liver mitochondria of normal C57BL/6J mice, two proline dehydrogenase activity components are demonstrable by electrophoretic resolution of Triton X-100 solubilized extracts. In mitochondria of PRO/Re mice, the activity of component 1 is not readily detectable. Residual proline dehydrogenase activity in PRO/Re mitochondria appears, therefore, to be due in large measure to activity component 2 which is more stable to incubation at 40 C, exhibits slower electrophoretic mobility, and is less reactive to menadione. Kinetic analyses demonstrate a Km (proline) for the Triton X-100 solubilized enzyme activities of PRO/Re and C57BL/6J liver mitochondria of 0.4 M and 2.9 X 10(-3) M, respectively. C57BL/6J enzyme activity is inhibited by high substrate concentration. The actins of PRO/Re liver obtained by differential centrifugation. Abnormal control of respiratory chain function in PRO/Re mitochondria appears to involve primarily proline oxidation, as indicated by the level of activity of several inner membrane enzymes.

Alleles↗
PubMed1972

Hyperprolinemia and prolinuria in a new inbred strain of mice, PRO-Re.

A hyperprolinemia was discovered, in a new inbred strain of mice, which was equivalent to about a sevenfold elevation above the concentration of proline in the blood of either of the original parental lines, or of 12 other inbred strains with diverse genetic constitution. In addition, mice of this PRO/Re strain exhibited a marked prolinuria, whereas the other 14 inbred strains had no proline detectable in their urine.

Amino Acid Metabolism, Inborn Errors↗