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Biomedical subjects

G Del Boccio

Publications and source records attributed to G Del Boccio.

34 records · Page 2Linked to original sources
PubMed1986

Activities of enzymes associated with the metabolism of glutathione in fetal rat liver and placenta.

Glutathione S-transferase, glutathione peroxidase, glutathione reductase and gamma-glutamylcysteine synthetase activities were measured in fetal rat liver and placenta supernatant at the 16th and 20th days of pregnancy. Compared with adult liver, low activities were found in both fetal liver and placenta. Both selenium-dependent and selenium-independent glutathione peroxidase activities were present in fetal liver, but only the selenium-dependent activity augmented as parturition advanced. Selenium-independent glutathione peroxidase was found to be absent in placenta. The progress of gestation is accompanied by a significant increase in conjugating capacity toward 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene and a significant decrease toward 1,2-epoxy-3-(p-nitrophenoxy)propane in fetal liver. Glutathione S-transferase activity in rat placenta diminished from day 15 to day 20 of gestation. The elevation of enzymatic activities involved in the synthesis and recovery of glutathione, which takes place in fetal liver and placenta, was thought to be adaptively responsive to the changes that occurred in glutathione-consuming enzymes.

Animals↗
PubMed1986

Glutathione redox cycle enzyme activities in erythrocytes of multiple sclerosis patients.

The erythrocytes of multiple sclerosis patients with elevated superoxide dismutase levels were tested for the activities of glutathione redox cycle enzymes. No differences were observed between multiple sclerosis and normal control erythrocytes when the activities were referred to either hemoglobin concentration or lactate dehydrogenase content. Our results indicate that no adaptative changes occur in the activities of glutathione redox cycle enzymes in erythrocytes of multiple sclerosis subjects as a consequence of an elevated superoxide dismutase level.

Adult↗
PubMed1986

Glutathione transferase of human breast is closely related to transferase of human placenta and erythrocytes.

An acidic form (pI 4.6) of glutathione transferase has been purified to homogeneity from normal and tumor specimens of human breast. The two proteins did not differ significantly in their molecular and catalytic properties. The enzyme has a molecular weight of 46,000 and is composed of two identical subunits. The data presented, including amino acid composition, substrate specificity and immunological studies, give strong evidence that the glutathione transferase of human breast, placenta and erythrocytes are similar if not identical proteins.

Amino Acids↗
PubMed1985

Glutathione-related enzyme activities in pregnant rat liver.

The levels of GSH-related enzyme activities during pregnancy were determined. A significant increase in Selenium-dependent GSH peroxidase and GSH S-transferase E activity was observed. A concomitant increase in gamma-glutamylcysteine synthetase was measured, which indicated an increased ability to synthesize the tripeptide.

Animals↗
PubMed1984

Isoelectric focusing of brain cortex GSH S-transferase activity in mammals: evidence that polymorphism is absent in man.

Specific activities of GSH S-transferase toward different model substrates were determined in the cytosol prepared from rat, guinea pig, rabbit, mouse, sheep, beef, pig and human brain cortex. The GSH S-transferase composition of the eight mammalian brain cortices was studied by using density gradient isoelectric focusing technique. Human brain cortex GSH S-transferase was resolved into a single peak of activity centered at pH 4.6, whereas the supernatants of all other mammals consisted of more than one enzymatic form. The kinetic properties of all forms isolated were compared.

Adult↗
PubMed1984

In vitro interaction of penicillins and cephalosporins with human placenta GSH S-transferase.

Human purified placenta GSH S-transferase was generally inhibited by penicillins and cephalosporins to a different extent. Among the seven penicillins tested the dihalogenate dicloxacillin and flucloxacillin were the strongest inhibitors. All cephalosporins showed competitive inhibition for the electrophilic substrate, while penicillins acted as non-competitive inhibitors. Exposure of the enzyme to cephalosporins led to the loss of the catalytic activity. Addition of reduced glutathione in the incubation system would induce the formation of a conformational state of the enzyme which prevents cephalosporins binding.

Cephalosporins↗
PubMed1979

[Preliminary study of the physical chemistry and catalytic properties of glutathione-S-transferase from human placenta].

Glutathione-S-transferase activity has been identified in the cytosol of human placenta. The specific activity measured is about 50% of that found in human liver. While some kinetic data have a close correspondence with those attributed to transferases of other sources, the molecular weight (60.000 daltons) and electric properties of this protein are unusual. The inhibitory effect of several non-substrate compounds suggests that also the placental Glutathione-S-transferase may play some role in detoxication of exogenous substances.

Cephaloridine↗
PubMed1976

Simultaneous purification of mitochondrial and cytoplasmic isozymes of aspartate aminotransferase from beef kidney.

Mitochondrial and cytoplasmic isozymes of aspartate transaminase are separated from beef kidney homogenates by ammonium sulfate fractionation. The mitochondrial isozyme is purified essentially as described earlier (Eur. J. Biochem., 1972, 26, 196-206) with slight modification in order to increase the yield. The cytoplasmic isozyme is purified by heat treatment followed by ion exchange cellulose chromatography and gel chromatography. The enzyme is pure in the ultracentrifuge and in polyacrylamide gel electrophoresis; it shows only one anionic band and no subforms. It has a molecular weight of 93,000 +/- 2000 and is composed of two subunits of 46,000 M.W. The enzyme has a specific activity of 49 micronmoles of oxalacetate x min-1 x mg-1. It contains 5 SH groups per subunit; three are directly titratable with p-mercuribenzoate and the other two only after addition of 0.2% SDS; there is no evidence of S-S groups. Km values for aspartate, glutamate, alpha-ketoglutarate and oxalacetate are in the order 1.25, 3.2, 0.06 and 0.41 mM in the cytoplasmic isozyme and 0.7, 5.0, 1.25 and 0.12 mM in the mitochondrial one.

Amino Acids↗
PubMedDate not supplied

Glutathione-S-transferase activity from rat placenta.

Glutathione S-transferase activity significantly decreased in the rat placenta from the 16th to the 20th day of gestation. Isoelectric focusing of rat placenta supernatant yielded essentially a single peak of glutathione S-transferase activity with I-chloro-2,4-dinitrobenzene as substrate, centred on pH 7.45. Substrate specificity measurements, as well as inhibitory studies, revealed pronounced differences between rat and human placental enzymes. Whether the biochemical differences between rat and human GSH-Trs are reflected in physiological differences remains to be ascertained. The sodium dodecyl sulphate (SDS) gel electrophoresis data on subunit composition showed that the rat enzyme is composed of two identical subunits whose molecular mass closely approaches that of human transferase.

Animals↗
PubMedDate not supplied

Improvement of diabetic microangiopathy with pycnogenol: A prospective, controlled study.

The aim of this study was to investigate the clinical efficacy of oral Pycnogenol (Horphag Research Ltd, United Kingdom) in patients with diabetic microangiopathy. Patients without a history of diabetic ulcerations were treated with Pycnogenol. Patients received oral Pycnogenol (50 mg capsules, 3 times daily for a total of 150 mg daily for 4 weeks). A group of 30 patients was included (severe microangiopathy); 30 comparable patients were observed as controls (no treatment during the observation period). All patients (age, 59 years; range, 55-68 years; male:female = 18:12) included in the treatment group completed the 4-week study. Also, all controls completed the follow-up period. There were no drop-outs. All included subjects had signs and symptoms of diabetic microangiopathy. The duration of diabetes-from the first signs/symptoms--was on average 7.5 years (SD = 3). After 4 weeks, microcirculatory and clinical evaluations showed a progressive decrease in skin flux at rest in the foot (indicating an improvement in the level of microangiopathy), a significant decrease in capillary filtration, and a significant improvement in the venoarteriolar response in all treated subjects. There were no visible effects in controls except a slight reduction in skin flux at rest in the foot. Treatment was well tolerated in both groups. In conclusion, this study confirms the clinical efficacy of Pycnogenol in patients with diabetic microangiopathy. The study indicates the clinical role of Pycnogenol in the management, treatment, and control of this common clinical problem. The treatment may be also useful to prevent diabetic ulcerations by controlling the level of microangiopathy.

Administration, Oral↗
PubMedDate not supplied

Purification and characterization of glutathione transferase of human thyroid.

An anionic (pI 4.6) isoenzyme of glutathione transferase was purified to homogeneity from human thyroid by affinity chromatography followed by isoelectric focusing. The content of enzyme was calculated to constitute about 0.2% of soluble proteins. The enzyme is formed by two identical subunits of 23,000 daltons approximately. The thyroid transferase did not catalyze the reduction of peroxides. Physical, catalytic and immunological analyses demonstrated extensive similarities between the thyroid transferase and the transferase from placenta, erythrocytes and breast. On the other hand, the thyroid transferase appears catalytically different from transferase 7-7, even if both cross-react with the antibodies raised against human placenta transferase.

Amino Acids↗