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Biomedical subjects

G Antonini

Publications and source records attributed to G Antonini.

At least 145 records · Page 8Linked to original sources
PubMed1985

Kinetics of redox-linked proton pumping activity of native and subunit III-depleted cytochrome c oxidase: a stopped-flow investigation.

The kinetics of oxidation of reduced cytochrome c by cytochrome c oxidase reconstituted into unilamellar vesicles (COV) has been followed by stopped-flow method in the time range 3 msec-1 sec. In the presence of valinomycin, the oxidation of cytochrome c is linked to proton ejection in the external medium, with an apparent stoichiometry (H+/e-) of 0.93 +/- 0.22, under conditions in which the enzyme is in the more active "pulsed" state (i.e., having undergone oxidation-reduction cycles). The time course of reaction indicates that the conformational change(s) involved in coupling the redox reaction to proton translocation is fast. Similar experiments carried out with cytochrome c oxidase depleted of subunit III show that proton-pumping is maintained, although with a lower efficiency (H+/e- = 0.5). The number of protons ejected per electron appears to be correlated to the value of the respiratory control ratio; although this result is partly due to an increase in the rate of diffusion back into the vesicles, a relationship between the respiratory control ratio and the efficiency of the proton pump may be inferred, suggesting a control of the H+/e-ratio.

Animals↗
PubMed1985

Electrophoretic subtyping of phosphoglucomutase locus 1 (PGM1) polymorphism in the Italian and Czechoslovakian populations.

About 3,500 subjects from Italy and Czechoslovakia have been analyzed by acid starch gel electrophoresis for the subtyping of PGM1 polymorphism. The Italian sample included three different subgroups, from Northern, Central and Southern Italy. The allele frequencies found in the three groups do not differ significantly from each other; the observed values in the pooled sample are: PGM1S1 = 0.594, PGM1F1 = 0.118, PGM2S1 = 0.231, PGM2F1 = 0.057. In the Czechoslovakian group, which differs significantly from the Italian population, the following allele frequencies were found: PGM1S1 = 0.639, PGM1F1 = 0.118, PGM2S1 = 0.180, PGM2F1 = 0.063. The analysis of 217 families did not show any exception to Mendelian inheritance of the patterns.

Czechoslovakia↗
PubMed1984

Inotropic effect of taurine in guinea-pig ventricular strips.

At 0.9 mM CaCl2 taurine prevented the negative inotropic effect due to low calcium concentration in guinea-pig ventricular strips but not in rat strips. This taurine effect was dose-dependent. The presence (in the perfusion medium) of beta-alanine, an inhibitor of taurine transport, antagonized the effect of taurine suggesting that the action of taurine was correlated to its transport. Neither propranolol, cimetidine nor indomethacin affected the response to taurine in guinea-pig ventricular strips.

Alanine↗
PubMed1983

Reoxygenation dysrhythmias in the isolated guinea-pig heart: sensitivity to prazosin, atenolol and practolol.

Isolated guinea-pig hearts were perfused aerobically for 60 min, then made anoxic for 30 min and finally reoxygenated for 30 min. The effects of prazosin, atenolol and practolol on contractility, coronary pressure, ECG and LDH release were examined. Prazosin and atenolol were able to reduce significantly the incidence of ventricular fibrillation and LDH release. The same two drugs increased the recovery of normal electrical activity after 30 min of reoxygenation. Practolol, on the other hand, was ineffective in reducing the incidence of ventricular arrhythmias and LDH release.

Animals↗
PubMed1983

Studies of the antimicrobial activity of ovotransferrin.

The antibacterial activity of ovotransferrin (conalbumin) against different bacterial species was studied in vitro. The most sensitive species were Pseudomonas sp., E. coli, S. mutans; and the most resistant ones S. aureus, Proteus sp., Klebsiella. The bacteriostatic activity of conalbumin in various conditions was also tested. The presence of bicarbonate ions always increased the activity of conalbumin, while an antagonistic effect of citrate was observed in bacteria with a receptor for the iron-citrate complex. Experiments with conalbumin covalently linked to Sepharose 4B indicated that its antibacterial activity may not be due simply to the removal of iron from the medium, but probably involves other metals and an interaction with the bacterial surface. The in vitro studies carried out with conalbumin and lactoferrin demonstrated that the two proteins produced a similar inhibition of growth of E. coli and S. mutans. The in vivo studies showed that the protective effect of conalbumin in newborn guinea pigs with E. coli by gastrointestinal route was similar to that naturally provided by the lactoferrin present in milk.

Animals↗
PubMed1982

A study of ten red cell enzymatic markers in the Naples' population. Report of a new GPT variant phenotype.

A sample of the population of Naples has been examined for several red cell enzyme markers. About 2,000 newborn have been analyzed for ACP, GLO I, and UMPK; 1,000 of them were also analyzed for PepA and PepB, and 500 for PGM1 and PGM2. In addition about 400 school children have been typed for the PGD and PGP polymorphisms. The observed gene frequencies for the polymorphic systems are: ACPA = 0.293, ACPB = 0.667 and ACPC = 0.040; GLO1 = 0.372; GPT2 = 0.462; UMPK2 = 0.029; PGM21 = 0.279; PGDC = 0.037; PGP1 = 0.953, PGP2 = 0.038 and PGP3 = 0.009. Moreover during the screening of PepA, PepB and GPT markers, some rare alleles have been encountered, one of which, at the GPT locus, has never been reported before. We propose for it the name GPT10.

Acid Phosphatase↗
PubMed1982

Antibacterial activity of matrix-bound ovotransferrin.

Ovotransferrin immobilized by covalent linkage to Sepharose 4B showed a bacteriostatic effect towards Escherichia coli similar to that of free ovotransferrin. The growth of the bacteria, after exposure to the gel-bound ovotransferrin and its removal, depended on the length of exposure. The results suggest that the antibacterial activity of transferrin is not due simply to the removal of iron from the medium.

Anti-Bacterial Agents↗
PubMed1982

Subtyping of phosphoglucomutase locus 1 (PGM1) polymorphism in some populations of Rwanda: description of variant phenotypes, "haplotype" frequencies, and linkage disequilibrium data.

Some populations of Rwanda (South Twa Pygmies, Hutu, and Tutsi) have been analyzed by acid starch gel electrophoresis for the subtyping of PGM1 polymorphism. The new polymorphic third PGM11 allele, the PGM1(1Twa), which we recently detected in Twa Pygmies from North Rwanda, has not been found in this survey, whereas the rare PGM1(6) allele attains subpolymorphic frequencies in all groups. Comparison between the various populations of Rwanda shows that they differ significantly from each other with the exception of South Twa Pygmies and Tutsi. A relatively low frequency (9.6%) of the PGM1(2S) allele appears to be typical of North Twa Pygmies; a low frequency of PGM1(2F) (1.2%-3.6%) has been found in all these groups but not in the Hutu (6.4%); and a particularly high incidence of the PGM1(1F) allele (the highest so far reported) has been observed in the South Twa Pygmies (20%) and in the Tutsi (18%). The PGM1(1Twa) and PGM1(6) enzymes, which in acid starch gel are not distinguishable, can be clearly differentiated by isoelectric focusing. In addition, the same technique has shown that the rare PGM1(7) allele observed in one Hutu is different from that found at polymorphic frequency in the Japanese and from a rare PGM1(7) allele found in Germany. On the very likely hypothesis that the PGM1(1S), PGM1(1F), PGM1(2S), and PGM1(2F) result from variations at two different polymorphic sites, 1/2 and F/S, within the PGM1 structural gene, all the available population data have been analyzed to investigate whether preferential combinations (haplotypes) were identifiable. Whereas Caucasians show a prevalence of 2F and 1S combination with an 8.02% mean value of linkage disequilibrium expressed as % Dmax, from the very few and scattered African data, it is impossible to draw any inference at present.

Alleles↗
PubMed1981

Subtyping of human red cell phosphoglucomutase locus 1 (PGM1) polymorphism: a third PGM1(1) allele common among Twa Pygmies from North Rwanda.

Seventy-eight Twa Pygmies from North Rwanda have been subtyped by acid starch gel electrophoresis for the polymorphism at the phosphoglucomutase locus 1 (PGM1). A third common PGM1(1) allele that has been named PGM1(1Twa) was detected in heterozygous association with both PGM1(1S) and PGM1(1F) alleles. The PGM1(1Twa) product is faster than those of the other two PGM1(1) alleles and has the same electrophoretic mobility as the rare PGM1(6) enzyme. The frequency of PGM1(1Twa) was found to be 0.45.

Alleles↗
PubMed1981

Resistance of genus Proteus to ovotransferrin.

A total of 100 strains of Proteus, clinically isolated, were tested for sensitivity to ovotransferrin and CrCl3. Only a minority of the tested strains were not capable of growing in the presence of these iron chelating substances. Significant differences in the resistance among the four species of Proteus were noticeable only by addition to the culture medium of CrCl3 5 mM. The fact that sensitive strains were capable of growing after addition of citrate to culture medium containing ovotransferrin or CrCl3 suggests the presence in the genus Proteus of a citrate-dependent iron transport system.

Chlorides↗
PubMed1980

Population genetics of red cell enzymes in Pygmies: a conclusive account.

In the course of a long-term research project, three groups of Pygmies and some non-Pygmy Central Africans have been examined for the following red cell enzyme markers: ACP, PGM1, PGM2, PEPA, PEPB, and PEPC, AK, ADA, and PHI. Several other red cell enzymes (ESD, CA1 and CA2, GPT, GLO, and DIA1) have been studied in only some of these groups. This paper reports all the information we obtained, including what we have already published. The following conclusions can be drawn from the whole body of data: (1) Gene patterns of Pygmies are those typical of other Africans (e.g.: lack of ADA2 and AK2 genes, low GPT2 gene frequency, polymorphism of the CA2 locus, and presence at polymorphic frequencies of PEPA2 allele. (2) Superimposed on this African genetic makeup, a number of Pygmy characters were identified, namely, a private polymorphism for the PGM26 Pygmy allele and possibly one for the PEPC2 allele, and particularly high ACPR and low PGM12 gene frequencies. (3) Some markers, especially PGM1 and ACP, turned out also to discriminate efficiently among different groups of Pygmies.

Black People↗
PubMed1979

Red cell glyoxalase I polymorphism in Italians. Report of a variant phenotype.

The glyoxalase I polymorphism was studied in 1,490 unrelated subjects from three different areas of Italy (Milan, Rome and Naples). The following frequencies of GLO2 allele were observed: Milan 0.57, Rome 0.59, Naples 0.61, and a significant difference between Milan and Naples was found (p less than 0.02). An anomalous phenotype is also described which permits us to postulate a new allele producing an isozyme with low activity and electrophoretically slower than those corresponding to GLO1 and GLO2 alleles.

Adolescent↗