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Biomedical subjects

G H Lathe

Publications and source records attributed to G H Lathe.

At least 19 recordsLinked to original sources
PubMed1976

Serum alkaline phosphatase, nucleotide pyrophosphatase, 5'-nucleotide and lipoprotein-X in cholestasis.

The nature of the stationary band of alkaline phosphatase, which occurs on starch gel electrophoresis of sera from patients with biliary obstruction, has been examined. Stationary alkaline phosphatase was eluted from Sepharose 4-B gel close to the void volume and together with the plasma membrane enzymes, nucleotide pyrophosphatase and 5'-nucleotidase, and with lipoprotein-X. Electron microscopy of concentrates of stationary alkaline phosphatase, prepared by ultracentrifugation and gel filtration, showed large (0.3--1 mum diameter) and small structures (30-70 nm diameter) by negative staining. The activity of the stationary alkaline phosphatase was associated in fixed sections with particles of about 10 nm X 40 nm resembling those of lipoprotein-X. It is suggested that the stationary alkaline phosphatase does not move into starch gel during electrophoresis because it is particulate. In agar electrophoresis the alkaline phosphatase which was stationary on starch gel moved towards the cathode with lipoprotein-X.

Adult↗
PubMed1970

The effect of steroids and nucleotidesoon solubilized bilirubin uridine diphosphate-glucuronyltransferase.

1. It was confirmed that bilirubin glucuronyltransferase can be obtained in solubilized form from rat liver microsomes. 2. Michaelis-Menten kinetics were not followed by the enzyme with bilirubin as substrate when the bilirubin/albumin ratio was varied. High concentrations of bilirubin were inhibitory. 3. The K(m) for UDP-glucuronic acid at the optimum bilirubin concentration was 0.46mm. 4. Low concentrations of Ca(2+) were inhibitory in the absence of Mg(2+) but stimulatory in its presence; the converse applied for EDTA. 5. UDP-N-acetylglucosamine and UDP-glucose enhanced conjugation by untreated, but not by solubilized microsomes. 6. The apparent 9.5-fold increase in activity after solubilization was probably due to the absence of UDP-glucuronic acid pyrophosphatase activity in the solubilized preparation. 7. The activation of solubilized enzyme activity by ATP was considered to be a result of chelation of inhibitory metal ions. 8. The solubilized enzyme activity was inhibited by UMP and UDP. The effect of UMP was not competitive with respect to UDP-glucuronic acid. 9. A number of steroids inhibited the solubilized enzyme activity. The competitive effects of stilboestrol, oestrone sulphate and 3beta-hydroxyandrost-5-en-17-one, with respect to UDP-glucuronic acid, may be explained on an allosteric basis.

Adenine Nucleotides↗
PubMed1970

The effect of oral contraceptive steroids on bile secretion and bilirubin Tm in rats.

1. The effect of oestrogens and progestogens and their 17alpha-ethinyl derivatives on bile flow, maximum rate of bilirubin secretion, serum and liver bilirubin has been studied.2. Both 17alpha-ethinyl substituted oestrogens and progestogens greatly reduced the basal bile flow. The parent compounds, oestradiol-17beta and 19-nortestosterone had little or no effect.3. A much larger dose of progestogens (40 mg/kg) than oestrogens (5 mg/kg) was needed.4. Between 12 and 48 h were required for 17alpha-ethinyloestradiol to produce the effect.5. Bilirubin maximum secretion rate (Tm) was little affected, the only significant reduction being produced by the 3-methyl ether of 17alpha-ethinyloestradiol (mestranol).6. Rises in serum conjugated bilirubin following infusion of bilirubin were produced by 17alpha-ethinyloestradiol and mestranol but not by the progestogens.

Animals↗
PubMed1969

The effect of tannic acid on the synthesis of protein and nucleic acid by rat liver.

1. As early as 1hr. after the intraperitoneal administration of tannic acid to rats, it could be demonstrated in the liver. At 3hr. the nuclear fraction contained the largest amount of tannic acid. 2. Nuclear RNA synthesis was inhibited in vivo 2hr. after the administration of tannic acid. Induction by cortisol of tryptophan pyrrolase was 90% inhibited at 24hr. 3. Incorporation of [1-(14)C]leucine into protein by liver slices from treated rats was decreased by 50% after 24hr. Its incorporation into postmitochondrial supernatant from treated animals was not inhibited. Incorporation into slices and postmitochondrial supernatants were inhibited in vitro by tannic acid. 4. The sequence of events: concentration of tannic acid in nuclei, inhibition of nuclear RNA synthesis, inhibition of protein synthesis and production of necrosis, is discussed.

Animals↗