Search PubMed⌕ Search

Biomedical subjects

J Constans

Publications and source records attributed to J Constans.

At least 163 records · Page 9Linked to original sources
PubMed1983

Unusual sialilation of the serum DBP associated with the Gc 1 allele in alcoholic cirrhosis of the liver.

The serum level of the 'vitamin D binding protein' (DBP) or Gc ('group-specific component'), its phenotype distribution and the quantitative estimation of the different electrophoretic isoforms were determined in a sample of healthy individuals (blood donors) and in patients with alcoholic hepatitis. It is shown that the serum DBP levels and the amount of the different electrophoretic isoforms are influenced by the protein phenotypes. In the patients an increased frequency of the Gc 1 allele is noticed. For the first time, an unusual form of the apo DBP protein was detected but only in the sera of the Gc 1 allele carriers. The protein form investigated by analytical procedures presents one more sialic acid residue than the usual Gc 1 protein. This unusual metabolic transformation of the DBP is mostly observed among male patients and is often associated with a deteriorating clinical outcome.

Adult↗
PubMed1983

A deficiency mutant of the Gc system.

In the course of a paternity investigation an apparent mother-child incompatibility was observed in the Gc system. An extensive family study was undertaken to test the hypothesis of a silent gene or null allele responsible for the contrary phenotypes: the mother had the type Gc 2, the son was GC 1. The apparent incompatibility was due to a "pseudo" silent allele, called Gc * 1, which controlled a group-specific component with extremely reduced serum concentrations. This double-band mutant could be differentiated from the Gc 1S bands by two-dimensional electrophoresis: isoelectric focusing (IEF)/6 M urea IEF. The allele Gc * 1 was found in 12 persons from this family, it was not associated with any apparent disease state. Also present in this family was the variant Gc 1C1. Pedigree analysis revealed a possible (not significant) distorted segregation ratio for the allele Gc * 1C1, which was found in 22 of 33 offspring from marriages with one parent heterozygous for Gc * 1C1.

Adult↗
PubMed1983

The polymorphism of the vitamin D-binding protein (Gc); isoelectric focusing in 3 M urea as additional method for identification of genetic variants.

Since the last report numerous new DBP (Gc) variants have been observed; at present a total of 84 different mutants can be distinguished. Several of them have similar electrophoretic mobilities and/or isoelectric points of conventional isoelectric focusing (IEF). IEF in polyacrylamide gels in the presence of 3 M urea is a convenient and efficient method for the detection of hidden variation.

Carrier Proteins↗
PubMed1982

Polymorphism of the haptoglobin peptides by isoelectric focusing electrophoresis and isoelectric point determinations.

In this investigation, the authors developed two new procedures: a micromethod for haptoglobin purification and the isoelectric focusing electrophoresis on slab polyacrylamide gel for peptide subtyping. These technics are adapted to the study of large sample series for population genetic surveys. The improvements obtained enabled us to disclose in an easy and highly reproducible way the Hp alpha and alpha 2 peptide chains. Electrophoretic separation of the alpha 2 FS, SS, and FF chains were greatly improved. Their frequencies estimated in a sample already investigated by the conventional PAGE presented higher values than previously described. New Hp alpha and alpha 2 mutants were also detected. For the first time, isoelectric points of the Hp peptides were determined; the values obtained are discussed with regard to their known amino acid structure.

Electrophoresis, Polyacrylamide Gel↗
PubMed1982

Transmission of the PiZ allele for alpha 1-antitrypsin deficiency: population genetic considerations.

It is shown that a simple preferential transmission of the PiZ allele by PiZ-heterozygous males for alpha 1-antitrypsin deficiency cannot maintain the observed polymorphism at the locus without invoking any viability or fertility selection against the PiZ gene carriers (heterozygotes or homozygotes). From the data on frequencies of PiZ alleles in Europe, the estimates of such selection coefficients are shown to be of the order of 5-20%, which seems too large for natural populations. Furthermore, an analysis of 26 nuclear families, each ascertained through a heterozygous PiZ or homozygous ZZ child, does not provide statistical evidence for such a hypothesis.

Alleles↗
PubMed1981

Gc revisited: six further Gc-phenotypes delineated by isoelectric focusing and by polyacrylamide gel electrophoresis.

Six newly observed Gc variants are described. The variants Gc 1A10, 1A11, 1A12, 1A13, and 1C11 have double band patterns. The anodal bands of these variants are susceptible to neuraminidase treatment. Gc 2A7 is a single band variant which is not altered by neuraminidase incubation. Polyacrylamide gel isoelectrofocusing with immunofixation and polyarcylamide gel electrophoresis appear to be efficient methods for the analysis of the Gc system.

Alpha-Globulins↗
PubMed1981

Binding of the apo and holo forms of the serum vitamin D-binding protein to human lymphocyte cytoplasm and membrane by indirect immunofluorescence.

The indirect immunofluorescence method is used to study the binding of the serum vitamin D carrier protein (DBP) to lymphocytes. It is shown that in vitro this serum protein will bind to the lymphocyte cytoplasm and intact membrane. This result is in agreement with recent evidence of an actin-binding protein present in the serum. Besides, a difference in the binding to the lymphocyte membrane is observed between the holo forms of the DBP with the different vitamin D derivatives. These findings could be relevant in illuminating the possible role of the DBP in the cellular metabolism of the active metabolites of vitamin D and in the cellular mobility.

Animals↗
PubMed1981

Gc, Tf, Hp subtype and alpha 1-antitrypsin polymorphisms in a Pygmy Bi-Aka sample.

Protein polymorphism is studied in more than 900 serum samples during different investigations conducted in a Bi Aka Pygmy group. The Gc, Tf and alpha 1-antitrypsin subtype polymorphisms were determined after isoelectric focusing while the haptoglobins alpha and alpha 2-peptides were studied on PAGE. A high frequency of the Hp2 gene is noted while Hp1F and Hp1S gene frequencies are similar. According to the Gc1S and Gc2 gene frequencies this group falls within the cluster of the melanoderm populations such as the Sara, Bantu and Peulhs. The two subtypes of TfC1 and TfC2 are present in this sample. TfC3 is absent. The TfD1 variant frequency is one of the highest observed in African groups. The alpha 1-antitrypsin polymorphism corresponds to the presence of the three PiM subtypes. No other variants are observed, neither PiS nor PiZ. For the first time a highly significant association is described between the TfD1 and Gc1A1 (GcAb) genes. Family pedigrees do not permit the ascertainment of the linkage between the two loci.

Black People↗
PubMed1981

Haptoglobin polymorphism among Saharian and West African groups. Haptoglobin phenotype determination by radioimmunoelectrophoresis on Hp O samples.

The haptoglobin (Hp) polymorphism is investigated in 11 African groups living in an area from the Algerian Sahara to Central Africa. More than 4,000 samples were examined. In the Saharian samples, the Hp1 gene frequency is higher than in any other African group. From north to south, a decrease in the Hp1 gene frequency is observed; in the Pygmy sample only, this frequency is lower than the frequency of the Hp2 gene. By means of a sensitive radioimmunoelectrophoresis, the presence of a residual Hp in Hp O sera in which the Hp polymorphism can also be determined can be revealed. Absence of Hp 1-1 and significant excess of Hp 2-2 individuals were observed. More Hp 2-1M phenotypes were detected in the Hp O population than in the non-Hp O population examined. In the Hp O samples, the influence of the phenotype distribution on the Hp gene frequencies is discussed. The heavy polymers of the Hp related to the presence of the alpha 2 chain (Hp2 gene product) are involved only in the biological mechanisms responsible for the presence of Hp O and Hp 2-1 M phenotypes among African groups.

Africa, Central↗
PubMed1980

Gc (vitamin D binding protein) subtype polymorphism and variants distribution among Saharan, Middle East, and African populations.

This article presents the results obtained by electrophoretic analysis of the group specific component polymorphism in more than 1,250 serum samples from populations living in the Sahara, the Middle East, and equatorial Africa. In addition to the alleles Gc1F and Gc1s, five variants, including one previously unknown, were found. The distribution of the alleles herein described permits speculation on exchanges and relations among the groups considered. The lowest frequencies of the gene Gc2 correspond to regions where sunlight is stronger. There is also a north-south gradient in the Gc1F gene frequency. This seems to parallel the gradient seen in skin pigmentation.

Africa, Northern↗
PubMed1980

A new procedure for the determination of transferrin C (Tf C) subtypes by isoelectric focusing. Existence of two additional alleles, Tf C4 and Tf C5.

Isoelectric focusing (IEF) is widely used for the determination of serum protein polymorphisms in forensic investigations. Because of non-genetic heterogeneity of some proteins and of protein-ligand dissociation observed after IEF standardization of procedures is necessary. In this article the authors point out the main difficulties encountered in studying the transferrin subtype polymorphism and describe a new and sensitive method. Two new Tf C subtypes were observed: Tf C4 in North American, Bolivian and Brazilian Indians, Tf C5 in Black Americans, both with polymorphic allele frequencies. In a Pyrenean population the allele frequencies for Tf C1, Tf C2 and Tf C3 were quite similar to those observed in a German population sample.

Alleles↗
PubMed1980

Pi M4: an additional Pi M subtype.

The authors studied Pi polymorphism using the Separator isofocusing method with slight modification. A new Pi allele was observed. Family pedigrees confirmed co-dominant inheritance with other Pi alleles. According to the electrophoretic mobility of its isoprotein bands, and to its frequency (0.04) this new allele is considered as a fourth Pi M subtype: Pi M4.

Alleles↗
PubMed1980

HLA-a, B typing in Basque and other Pyrenean populations.

Fourteen HLA-A and 18 HLA-B antigens were studied in three samples of Pyrenean populations: 198 unrelated individuals of a "Pays Basque" group; 212 non-Basque individuals from a valley in Bearn, l'Ouzom; and 73 non-Basque individuals from the neighboring valley of Bareges. The results in the Basque and the non-Basque people from l'Ouzom were comparable: the gene frequencies of HLA-A29, Aw19.2, B17 were increased and the haplotypes HLA-Aw19.2, B18; A29, B12; A2, B5; A1, B17 were found frequently with a striking linkage disequilibrium; HLA-B18 had an increased gene frequency in all these Pyrenean populations, while Bw35 was frequent in l'Ouzom and Bareges, but not among the Basques. The characteristics of Bareges were very different: the gene frequencies of HLA-A2, A11, B7 were increased while the frequency of HLA-B5 was low; the most characteristic haplotypes were HLA-A2, B12; A2, B18; A11, Bw35; A11, B27. It is interesting to note discrepancies between ethnic and HLA classification of the Basques and the non-Basque population of l'Ouzom. The HLA characteristics are quite different in the Hareges sample, more closely resembling those of Northern Europe.

Ethnicity↗
PubMed1980

High frequency of the properdin factor Bf F1 and its linkage to HLA in French Basques.

We studied 201 unrelated French Basque individuals for HLA and Bf polymorphisms. The haplotypes of eighty-seven of them were deduced from family studies. The results show the frequency of the Bf F1 allele (0.1393) which is the highest one currently reported. They confirm the high frequencies of HLA-Aw19.2 and B18 previously reported in that population and show that a whole haplotype with strong linkage disequilibria, namely Aw19.2, Cw5, B18, Bf F1, DRw3 is frequent. On the other hand, the gene frequency of Bf S is decreased (0.5497) as compared with the other European Caucasoïd populations, while a slight increase in the Bf F gene frequency (0.2960) appears. These results point out that it is of importance to consider the genetic background choosing the population where linkage disequilibria are to be studied.

Alleles↗
PubMed1980

Study of red blood cell and serum enzymes in five Pyrenean communities and in a Basque population sample.

Until recently, no data on genetic polymorphisms in the populations living on the northern side of the Pyrenees have been available, except for the Basques. Several investigations were done lately on rural communities in various geographic zones in the Pyrenees from the eastern to the western part. In this paper, the results for the following enzyme polymorphisms are reported: acid phosphatases, AK, ADA, PGM1 and PGM2, 6PGD, NADH diaphorase, SOD, MDH, TGP, G6PD, C5 esterase (E2 locus), serum cholinesterase (E1 locus). Significant variation in gene frequencies was observed over the distinct geographic zones for the main polymorphic system. Furthermore, some rare alleles were found: a new G6PD variant (Luz-Saint-Sauveur), the presence of ADA3 and ADA5 alleles in two groups of the Central Pyrenees, a Dia2 gene among Basques and in the Pays de Sault, a high rate of Ea1 allele in the Basque group. The values obtained for the degree of heterozygosity are in agreement with the relative isolation of the different groups studied and confirm the importance of sociocultural factors in the evolution of the genetic background of rural communities in Europe.

Acid Phosphatase↗