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Biomedical subjects

R M Corbo

Publications and source records attributed to R M Corbo.

At least 37 records · Page 2Linked to original sources
PubMed1993

Persistence of sister chromatid exchange by 9-beta-D-arabinofuranosyladenine in Chinese hamster ovary cells cultivated in vitro.

The cytogenetic activity of 9-beta-D-arabinofuranosyladenine (ara-A), a known antitumor agent with an unknown mechanism of action (possibly acting via demethylation and/or decrease in DNA synthesis), has been tested in Chinese hamster ovary (CHO) cells cultivated in vitro, with respect to its ability to induce sister chromatid exchange (SCE). The agent shows no effect on cell cycle parameters (proliferation and mitotic indices) at concentrations up to 100 microM, when administered in pulses ranging from 3 to 12 h. Furthermore, even if administered over the entire treatment period (24 h), a severe cell cycle delay appears only at a concentration of 100 microM. A clear increase in the SCE frequency is produced starting from a concentration of 10 microM, irrespective of the treatment protocol (i.e. pulse versus continuous). This effect on the SCE frequency is maintained for as long as 10 cell cycles after removal of the agent. A partial inactivation of S-adenosyl-L-homocysteine (AdoHcy) hydrolase seems to be produced for as long as 6 h after agent removal. We suggest that under our experimental conditions ara-A exerts its action through a heritable epigenetic modification.

Adenosylhomocysteinase↗
PubMed1992

Kinetic properties of the common electrophoretic variants of human S-adenosylhomocysteine hydrolase (AHCY): the effect of four nucleoside analogue inhibitors.

Red blood cell S-adenosylhomocysteine hydrolase (AHCY) from individuals of 1, 2-1 and 3-1 phenotypes was partially purified and Km and Vmax determined in the absence and in the presence of the following inhibitors: 3-deaza-adenosine (DZA), 3-deaza-aristeromycin (DZAry), 2-chloro adenosine (2-Cl-ado) and purine riboside (or nebularine). The three phenotypes 1, 2-1, 3-1 showed similar Km (32.58, 39.22 and 34.84 microM respectively), but the ratio Km/Vmax was statistically different. DZA and DZAry appeared to be strong competitive inhibitors. The AHCY 1 phenotype was more resistant to their action, while the 3-1 variant was more sensitive. 2-Cl-ado and purine riboside were weaker inhibitors; the type of inhibition varied among the three phenotypes, but, again, the AHCY 1 phenotype was less sensitive than the other two.

2-Chloroadenosine↗
PubMed1992

Distribution of ORM1, C6, C7 and APO C-II allele frequencies in populations from mainland Italy and Sardinia.

The genetic variation of the human plasma proteins ORM1, C6, C7 and APO C-II was investigated by isoelectric focusing followed by immunoblotting in populations from mainland Italy and Sardinia. The frequencies of ORM1*1 were 0.621 and 0.564, while those of C6*A were 0.657 and 0.706 on mainland Italy and in Sardinia, respectively. In the Roman sample, 8 heterozygotes with C6 variant alleles were encountered, while none were observed in Sardinians. For C7 and APO C-II a number of heterozygotes with the rare alleles C7*2 and APO C-II*2 were found, but their frequency did not reach polymorphic levels in either population. The two populations showed a significant difference in the gene frequencies distribution for ORM1.

Alleles↗
PubMed1991

Genetic polymorphisms of the A and B subunits of human coagulation factor XIII in mainland Italy and Sardinia: description of a new FXIIIA variant allele.

The distribution of the two alleles of FXIIIA and the three alleles of FXIIIB were studied in populations from mainland Italy and from Sardinia. The frequencies of the FXIIIA*2 allele were 0.266 and 0.265. The frequencies of FXIIIB*1 were 0.787 and 0.765; of B*2, 0.070 and 0.094; of B*3, 0.143 and 0.141. A new cathodal FXIIIA allele (A*7) was described in the Rome sample. No significant difference in the distribution of allele frequencies for either system was found between the two populations studied. For typing both markers, good results were also obtained by using whole blood instead of plasma.

Alleles↗
PubMed1991

Human placental 17 beta-estradiol dehydrogenase: enzymatic activity in the last weeks of pregnancy and electrophoretic data.

A specific electrophoretic method for human placental 17 beta-estradiol dehydrogenase (17-HSD; EC 1.1.1.62) has been performed and a sample of about 180 placentae from Italian women has been examined. A common phenotype and only one electrophoretic variant have been observed. Also 17-HSD activity has been tested. A statistically significant negative correlation has been found between 17-HSD activity and both gestational age and birth weight in the last weeks of gestation in a group of at term newborns with weight appropriate for date. This reduction in enzymatic activity is in good agreement with the data on estrone and estradiol which both show a declining rate of increase in the last weeks of pregnancy.

Birth Weight↗
PubMed1991

A survey of six genetic markers on the populations of Punjab and Rajasthan (India).

190 Punjabis (Hindus and Sikhs) of Chandigarh and 152 Hindus of Jodhpur (Rajasthan) were examined for six genetic markers, four of which (APO C-II, C6, C7 and FXIIIA) were not studied before in Asiatic Indians. For APO C-II and C7 only the common phenotype was found in a total of 229 and 99 subjects, respectively. For the remaining four markers the two samples were pooled since the gene frequency estimates were not significantly different: FXIIIA*2 = 0.205 +/- 0.016; C6*B = 0.366 +/- 0.037; PGM1*2 = 0.247 +/- 0.017; PGD*C = 0.041 +/- 0.008. These data may contribute to evaluate the extent of the Mongoloid genetic admixture into the Caucasoid gene pool of the Punjab and Rajasthan Hindu population.

Apolipoprotein C-II↗
PubMed1988

Effect of some thiol reagents on erythrocyte adenosine deaminase (ADA) activity.

The effect of three thiol reagents on erythrocyte adenosine deaminase (ADA) activity has been studied. Oxidized glutathione and iodoacetate do not alter ADA activity, while the treatment with p-chloromercuribenzoate at similar concentrations results in a reduction of enzymatic activity which is statistically significant only for ADA 1, but not ADA 2-1 phenotype haemolysates.

Adenosine Deaminase↗
PubMed1987

Polymorphism of S-adenosylhomocysteine hydrolase in Italy.

S-adenosylhomocysteine hydrolase (SAHH) polymorphism has been investigated in the Italian population. Three common alleles, SAHH*1, SAHH*2 and SAHH*3, have been observed and the estimated gene frequencies are 0.968, 0.023 and 0.009, respectively. SAHH activity has been assayed in 50 healthy individuals and the mean activity was 0.043 +/- 0.017 mumol uric acid/min/g Hb at 37 degrees C. Five heterozygotes for adenosine deaminase deficiency and three heterozygotes for purine nucleoside phosphorylase deficiency showed SAHH within the range of the normal distribution. The effects of some thiol reagents on red blood cell SAHH electrophoretic pattern have been investigated.

Adenosine Deaminase↗
PubMed1985

Human placental glucose dehydrogenase: IEF polymorphism in two Italian populations and enzyme activity in the six common phenotypes.

Glucose dehydrogenase (hexose-6-phosphate dehydrogenase) has been assayed qualitatively and quantitatively in more than 600 human placentae collected in two Italian populations. The gene frequencies for GDH1, GDH2 and GDH3 were, respectively, 0.66, 0.21 and 0.12 in Continental Italy and 0.65, 0.23 and 0.12 in Sardinia. Among the six common phenotypes there was no difference in catalytic activity.

Gene Frequency↗
PubMed1985

Relationship between human serum placental alkaline phosphatase and the ABo and Rh compatibility status in pregnancy.

458 unrelated healthy women at various gestational ages were examined for serum heat-stable alkaline phosphatase (HSALP) activity. The sample was subdivided into four groups according to the compatibility mating type in the ABO and Rh systems: double compatible, ABO incompatible, Rh incompatible and double incompatible. The results confirm the exponential growth of serum placental isoenzyme as a function of gestational age and show that the moment of appearance of the placental isoenzyme is six weeks earlier in double incompatible matings.

ABO Blood-Group System↗
PubMed1983

Human phosphoglucomutase locus 1: red cell enzymatic activities associated with common isoelectric focusing phenotypes.

Human phosphoglucomutase activity has been determined in red blood cells obtained from 348 unrelated subjects. The mean activities attributed to the four common PGM1 alleles, expressed as micromoles of G6P produced per gram of Hb per hour were 53 for PGMa31, 60 for PGMa11, 61 for PGMa41 and 72 for PGMa21. The relative amount of variation associated with the electrophoretic polymorphism was estimated as 24%.

Alleles↗
PubMed1982

Human placental alkaline phosphatase electrophoretic alleles: quantitative studies.

Human placental alkaline phosphatase (ALP) activity has been determined in specimens obtained from 562 Italian subjects. The mean activities of the three common homozygotes (Pl 2 = 4.70 +/- 0.24, Pl 1 = 4.09 +/- 0.08, and Pl 3 = 2.15 +/- 0.71 mumol of p-nitrophenol produced) were significantly different. The differences among the various allelic forms account for 10% of the total quantitative variation of the human placental alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1981

A survey of serum protein and enzyme polymorphisms in the district of L'Aquila (Italy).

A random sample of more than 500 subjects collected in the district of l'Aquila (Italy) has been studied for the following genetic markers: ADA, EsD, G-6-PD, 6-PGD, SOD-A, Hp, C3. The gene frequencies of all the systems examined were similar to those observed in Rome. Rare variants have been found for 6-PGD, C3 and SOD-A. The last one showed an electrophoretic pattern different from the only other variant so far observed in the Italian population.

Adenosine Deaminase↗
PubMed1979

C'3 polymorphism in Italy.

C'3 phenotype and gene frequencies observed in two Italian samples are reported. The allele frequencies resemble those reported for other Caucasian populations. Five different rare variants are described.

Complement C3↗
PubMed1979

Placental alkaline phosphatase: population studies in Sardinia and data on the anthropological value of this genetic marker.

The analysis of human placental alkaline phosphatase polymorphism in Sardinia has shown a further difference in the genetic structure of this population in comparison with the populations of Continental Italy and Western Europe. Ethnic and geographic variations in world distribution of placental alkaline phosphatase gene frequencies suggest the considerable anthropological value of this genetic marker.

Alkaline Phosphatase↗