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Biomedical subjects

A Arduini

Publications and source records attributed to A Arduini.

At least 73 records · Page 4Linked to original sources
PubMed1988

Effect of ischemia and reperfusion on antioxidant enzymes and mitochondrial inner membrane proteins in perfused rat heart.

Experiments were performed to investigate the effects of 60 min severe global ischemia followed by 30 min reperfusion on the antioxidant enzymatic system in the isolated perfused rat heart. Ischemia induced a significant increase of cytoplasmic and mitochondrial selenium-dependent glutathione peroxidase (EC 1.11.1.9) activity. In reperfused hearts, only the mitochondrial form showed a further significant increase. Glutathione reductase (EC 1.6.4.2) was increased in ischemic hearts, whilst the reperfused hearts showed a decrease towards the level found in aerobic hearts. Mitochondrial superoxide dismutase (EC 1.15.1.1) activity was depressed in ischemic as well as in reperfused hearts, though the cytoplasmic form was unmodified. Catalase (EC 1.11.1.6), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glutathione transferase (EC 2.5.1.18) activities were unchanged throughout the experiment. Ischemia and reperfusion induced a significant fall in tissue-reduced glutathione content concomitant with an increase of its oxidized form. We have also studied the mitochondrial inner membrane proteins for both molecular weight, with Coomassie blue, and thiol status, with monobromobimane stain, using a sodium dodecyl sulfate polyacrylamide gel electrophoresis technique. Neither ischemia nor reperfusion effected any relevant modification of the molecular weight of the mitochondrial inner-membrane proteins either in the presence or absence of a reducing agent. However, two of these proteins with an apparent molecular weight of 52,0000 and 12,000 showed a decrease in the monobromobimane stain, probably due to the oxidation of their thiol groups.

Animals↗
PubMed1988

Change in plasma amino acid concentrations during breath-hold diving at high altitude.

We studied the plasma concentration of various amino acids in 6 Italian sport divers in Italy and at approximately 4,500 m altitude in Peru; 6 Peruvian inhabitants were examined for comparison. We attempted to create a situation of pronounced hypoxia in muscles by breath-hold diving at altitude. The diving reflex diverts blood away from muscles while diving increases central oxygen tension and prevents loss of consciousness. Differences in certain amino acids, probably related to diet, were noted between Italy and Peru. Increases in concentration of plasma alanine and some branched-chain amino acids occurred after breath-hold diving. These changes were similar to those seen after prolonged hard exercise, even though physical work was low. Hypoxia in muscles, common during hard work and during breath-hold diving at altitude, might thus be the stimulus for amino acid release from working muscles.

Adult↗
PubMed1987

Cytogenetics and acute non lymphocytic leukemia.

The authors report haematologic and cytogenetic data from 47 patients with ANLL, demonstrating the usefulness of cytogenetic studies for the classification as well as for the prognosis of this disorder. Chromosome studies also permitted the classification of marrow cellularity in: all diploid metaphases (NN), diploid and aneuploid metaphases (AN), and all aneuploid metaphases (AA). The remission rate for patients in whom only normal metaphases were detected (NN patients) was 83% while the remission rates were 67% and 33% respectively for patients in whom both normal and abnormal metaphases were seen (AN patients) and for those in whom only abnormal metaphases were noted (AA patients). In all FAB subgroups, complete remission was related to chromosomal abnormalities, except for M4 patients who evidenced a large number of complete remissions, although presenting more chromosomal abnormalities. The longer survival in this subgroup may be related to rearrangements of chromosome 16, which is associated with a better prognosis.

Acute Disease↗
PubMed1986

Phenylhydrazine-induced changes in erythrocyte membrane surface lipid packing.

Phenylhydrazine-induced oxidative damage in red cells results in increased binding of merocyanine 540, a fluorescence probe sensitive to changes in lipid packing. Fluorescence polarization studies with diphenylhexatriene did not reveal major changes in order parameters both in intact red cells and lysates treated with phenylhydrazine. These fluorescence studies indicate that major changes are observed in membrane lipids. Analytical studies of membrane phospholipids revealed a significant decrease in phosphatidylethanolamine. The results of the fluorescence and lipid studies, taken in association with our previously reported findings on spectrin and other cytoskeletal protein degradation in red cells exposed to phenylhydrazine, suggests that degradation of cytoskeleton membrane proteins is also responsible for changes in the lipid bilayer surface of the red cell membrane.

Diphenylhexatriene↗
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↗
PubMed1985

Spectrin degradation in intact red blood cells by phenylhydrazine.

The effects of phenylhydrazine on intact red cells and on red cell ghost membrane proteins were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In intact red cells 1 mM phenylhydrazine induced a marked decrease in intensity of the alpha- and beta-bands of spectrin without the formation of high molecular weight materials. Phenylhydrazine was also responsible for cross-linking of hemoglobin, which is apparent by the appearance of two new broad bands on the gel. Membrane glycoproteins were unaffected. Electrophoretic patterns of cytoskeletal proteins from phenylhydrazine-treated red cells obtained on two-dimensional SDS-polyacrylamide gels and stained with Coomassie blue or fluorescently labeled with monobromobimane indicated the presence of a new band between bands 4.2 and 5 at 60-65 kilodaltons (K). An immunoelectrophoretic blotting procedure utilizing polyclonal IgG antibodies for alpha- and beta-spectrin of the red cell cytoskeletal proteins revealed that the band observed at 60-65 K in the two-dimensional SDS-PAGE studies reacted with the antibodies. The presence or absence of glucose in the incubation medium and modification of oxyhemoglobin to met- or carboxyhemoglobin in the red cells did not protect the phenylhydrazine-mediated degradation of the major cytoskeletal proteins. Metal chelators and antioxidants had no effect on membrane protein changes. Ghost red cell proteins did not undergo changes at 1 mM phenylhydrazine in the presence or absence of hemoglobin, although at 5 mM phenylhydrazine the appearance of a faint high molecular weight band was observed. These results indicate that spectrin degradation without significant polymerization can be induced by phenylhydrazine.

Antioxidants↗
PubMed1985

Effect of lipid peroxidation on the accessibility of dansyl chloride labeling to lipids and proteins of bovine myelin.

In our previous studies we have demonstrated that bovine myelin appears highly susceptible to oxidative damage to both its lipid and protein composition. In order to determine whether these alterations would affect the accessibility of myelin components to a fluorescent probe, we have performed various labeling experiments using dansyl chloride. Results from labeling of purified bovine myelin treated with or without cumene hydroperoxide show that basic protein from treated myelin incorporated more dansyl chloride than basic protein from untreated myelin. This increase of labeling could be prevented by the addition of the antioxidant agent, butylated hydroxytoluene. This evidence suggest that lipid peroxidation may play an important role in the pathogenesis of inflammatory demyelinating diseases.

Animals↗
PubMed1984

[Adjuvant potential of vitamin E in the induction of experimental allergic encephalomyelitis: histological aspects].

In this study we report the effect of Vit. E, as an immunostimulating factor, on the induction of Experimental Allergic Encephalomyelitis in Lewis rat. The animals were inoculated intracutaneously in the plantar areas with emulsion of isologous spinal cord suspensed in Incomplete Freund's Adjuvant (IFI) and Vit. E. Histologic examination revealed the basic lesion of a perivenous cuff of mononuclear cells and small areas of demyelinated axons. The clinical signes are graded in order to the time of induction. It is possible an action of "adjuvanticity" of Vit. E on the various cells involved in the immune response by cell transformation and moltiplication.

Adjuvants, Immunologic↗
PubMed1984

Superoxide dismutase, reduced glutathione and TBA-reactive products in erythrocytes of patients with multiple sclerosis.

Superoxide dismutase, reduced glutathione and lipid peroxides levels were determined in the erythrocytes of multiple sclerosis patients. Superoxide dismutase activity and the malonyldialdehyde production rate were found to be significantly enhanced. The isoelectric focusing pattern of superoxide dismutase from multiple sclerosis and normal subjects erythrocytes was substantially overlapping. Our results indicate the occurrence of a higher susceptibility of multiple sclerosis erythrocytes to lipid peroxidation.

Erythrocytes↗
PubMed1984

High-dose neuroleptics: uncontrolled clinical practice confirms controlled clinical trials.

The strategy of high-dose intramuscular haloperidol as routinely applied in a general hospital psychiatric ward to 74 successive patients, 33 of whom stayed only up to seven days, and a further 34 up to 15 days, led to a complete recovery in only six, and complete lack of change in 23. Adverse reactions were recorded in 42, severe enough to stop treatment in eight; there were three deaths. In view of this risk-benefit analysis, systematic application of this high dose strategy to get a more rapid turnover of patients is unjustified.

Adolescent↗
PubMed1983

Glutathione peroxidase, glutathione reductase, glutathione S-transferase, and gamma-glutamyltranspeptidase activities in the human early pregnancy placenta.

GSH peroxidase, GSSG reductase, GSH S-transferase, and gamma-glutamyltranspeptidase activities were measured in the supernatant of 13 human early pregnancy placenta homogenates. From measurements of GSH peroxidase activity with both H2O2 and cumene hydroperoxide as second substrate it was deduced that immature placenta contains only the Se-dependent form. All the specimens investigated exhibited GSSG reductase and gamma-glutamyltranspeptidase activities. GSH S-transferase activity was noted only using 1-chloro-2,4-dinitrobenzene as electrophilic substrate, while no detectable activity was found with 1,2-dichloro-4-nitrobenzene, 1,2-epoxy-3-(p-nitrophenoxy) propane, and p-nitrobenzylchloride. It is concluded that human placenta is equipped, from early pregnancy, with the enzymatic systems which are involved in GSH-mediated cellular detoxication and in preserving the integrity of the sulfhydryl status of the cells.

Female↗
PubMed1983

Continuous correlation between brain activities.

In free-behaving cats, bearing chronically implanted electrodes, the cross-correlation coefficients between EEG, EMG and unit activity in the Lateral Geniculate nucleus (LGU) have been computed continuously at 1 sec interval for epochs of several minutes, in the three basic physiological states: slow wave synchronized sleep (S-sleep), REM-sleep and Arousal. The coefficients exhibit continuous and aperiodic oscillations between high positive and high negative values. The means of the coefficients for each pair of variables exhibit significant differences between the three states. The phase times also are varying significantly for each variable pair in different states. During the transition from one state to another the coefficients follow characteristic time patterns. In the stationary phase of the different physiological states the correlation coefficients follow similar waxing and waning patterns. Embedded in the steady waxing and wanings of the coefficients are frequently found r time patterns similar to those of a state transition: the incomplete and sham transitions. All the results support the hypothesis that the diffuse projecting systems are inducing a continuous pressure to change the state of the brain activity, which is revealed by the changing of the correlations between the different brain structures.

Animals↗
PubMed1982

Glutathione S-transferase activity from guinea-pig brain: a comparison with hepatic multiple forms.

1. Specific activities of glutathione S-transferase towards four model substrates were determined in guinea-pig brain 50,000 g supernatant and compared with those obtained for liver and kidney extract. 2. By using 1-chloro-2,4-dinitrobenzene as substrate, glutathione S-transferase activity was measured in different anatomical regions of brain; cerebellum expressed the highest conjugating capacity. 3. Brain glutathione S-transferase was resolved into four major peaks (PI 6.10, 6.60, 7.15, 7.65) each having similar kinetic constants for both substrates GSH and 1-chloro-2,4-dinitrobenzene. 4. Likewise, four forms, focused at pH 6.45, 7.14, 7.50 and 8.88, were obtained from liver. 5. Unlike hepatic tissue, brain does not possess the highly alkaline form which displays Se-independent GSH peroxidase activity. 6. Several psychotropic agents, including chlorpromazine and chlorazepate, produced a considerable in vitro inhibition on brain transferase activity.

Animals↗
PubMed1982

Measure of the correlation between brain activities: a methodological approach.

This paper is a short review of the work done on methods of measuring nerve activity. 1) It is proposed that physiologically meaningful measures of mass activities should have the character of time averages. The advantages of continuous integration are discussed. 2) For a comparison of the mass activities from different structures the method of the ongoing cross-correlation coefficient is proposed. The properties of the method are discussed and some preliminary results are reported showing its usefulness in the investigation of the so-called steady state activities.

Brain↗
PubMed1979

In-phase brain activities during arousal and sleep.

EEG of sensorimotor area, EMG of neck muscles and unit activity in lateral geniculate (LG) nucleus, recorded in freely moving cats, were analysed for the presence of correlations between them. The 3 activities were first integrated with a 2 sec time constant, then a correlation coefficient was assessed between time-linked points of the 3 records for periods of 40 sec. The average vlaues of the correlation coefficients were found to increase from arousal through slow synchronized sleep (S sleep), reaching the highest value in REM sleep. The average of the values in REM was found to be significantly different from those in arousal and S sleep. These differences were statistically significant for the correlation coefficients between EEG and LG activities, as well as of EMG and LG. On the contrary, the correlation between EEG and EMG, which may be thought of as having more direct anatomical connections and a higher degree of physiological dependence, did not change as a function of the different physiological states.

Animals↗