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C Ropartz

Publications and source records attributed to C Ropartz.

At least 37 records · Page 2Linked to original sources
PubMed1976

Deletion of hinge region of human myeloma IgG1 molecule (protein LEC) associated with nonexpression of G1m (3) and Km (1, 2) allotypes. A possible genetic explanation at the DNA level.

In this paper we report the structural basis for the nonexpression of G1m(3) and Km (1,2) allotypes in an IgG1 (kappa) human myeloma protein (protein LEC). Heavy and light chains spontaneously dissociate in sodium dodecyl sulfate polyacrylamide gels. Light chains appear to be covalently S-S bonded. Analysis of cysteine-containing peptides shows that the heavy chain of the IgG protein LEC has a deletion of residues 216-230, thus encompassing the entire hinge region. An arginine residue, characteristic of the G1m(3) marker is present at position 214. An alanine at position 153 and a leucine at position 191 of the light chain, characteristic of the Km (1, 2) allotypes, are present. It is likely that the double Km and Gm lack of expression is the result of the deletion. The genetic implications of the sequence of this protein are discussed.

Amino Acid Sequence↗
PubMed1976

Antigenic determinants of heavy chain variable regions: immumological typing of the human immunoglobulin VHIII subgroup.

An antigenic determinant of the VHIII variable region subgroup was defined by means of a heterologous specific antiserum using a hemagglutination inhibition procedure. The specificity of this antiserum was established in inhibition experiments with proteins either of known primary structure or belonging to a definite VH subgroup. A series of IgG, IgA, IgM and IgD monoclonal proteins was examined for the presence of this VHIII subgroup antigenic determinant. The data showed that 50% of the IgG, 62% of the IgA, 55% of the IgM and 41% of the IgD were VHIII-positive, and that certain "blocked" monoclonal immunoglobulins belonged to this subgroup. A preferential association of the VHIII antigenic determinant with the IgG1 and IgG3 subclasses was observed among IgG myeloma proteins while the preferential association was only observed with the IgG1 subclass when anti-Rh antibodies were studied. The VHIII subgroup exhibited nonallelic behavior.

Epitopes↗
PubMed1976

Quantitative studies of Gm allotypes. I. Reappraisal of the method using an autoanalyzer.

In this study, various parameters for the autoanalyzer hemagglutination-inhibition circuit applied to Gm studies, were examined. Details are given of modifications of this circiut and related methodology, that improve its precision and the reproducibility of results: use of a cells counter, effects of temperature, PVP, Tween 20, anti-Gm concentration, etc. The effects of age, storage and freezing on quantitative Gm allotypes antigenicity are also stressed.

Antibodies, Anti-Idiotypic↗
PubMed1976

Expression of genetic markers of erythrocyte immunoglobulin G autoantibodies in autoimmune hemolytic anemia.

The Gm allotype constitution of the autoantibody molecules and the serum Gm phenotypes were determined in 19 patients with autiommune hemolytic anemia of IgG type. The results showed that the known heterogeneity of the antierythrocyte autoantibodies in this disease concerns not only the immunoglobulin class and the isotypic subclass, but also the genetic markers of these molecules. Evidence was obtained that the anomalous production of antierythrocyte autoantibodies is polyclonal, that thse autoantibodies belong mainly to the IgG1 isotypic subclass, and that they have a preference for the Gm(1) allotype. In addition, certain of the findings point to a preferential expression of the Gm(1,21) haplotype.

Anemia, Hemolytic, Autoimmune↗
PubMed1976

Genetic variants of serum alpha1-antitrypsin (Pi types) in Portuguese.

The results of Pi typing on 330 Portuguese from the area of Lisbon are reported. We found six phenotypes and four alleles out of the 24 described in the literature. The allele PiM is the most frequent as in other populations, PiS shows a high frequency (0.1152), and PiF is absent, which agrees satisfactorily with former studies carried out in Spain. These results are compared with others and the entity of the Iberian population is evoked.

Female↗
PubMed1976

[Rheumatic manifestations in 80 cases of Crohn's disease].

Out of a series of 80 patients suffering from Crohn's disease, 31 presented rheumatic manifestations. In 16 subjects this took the form of synovitis closely dependent on the enteritic evolution, which developed after the alimentary symptoms, and which worsened as they did and sometimes regressed as they did following medical or surgical treatment. In combination with erythema nodosum, aphtosis, and conjunctivitis, synovitis appears to be the expression of an immune response to the enteritic lesion. Three cases of chronic polyarthitis and 6 cases of asymptomatic sacro-ileitis were also observed, and 6 cases of spondylarthritis of a minor radiological type were observed that evolved independently of the Crohn's disease. Typing according to the HLA system using 26 antigens was carried out in 44 subjects; no difference in phenotype frequency was found between a control group (blood donors) and the group of subjects with Crohn's disease alone; however, the antigen W 17 was found significantly more frequently in those subjects with peripheral arthritis and the antigen W 27 was found more frequently in those with spondylarthritis. These findings suggest, although it is not certain, the existence of genetic susceptibility to rheumatic manifestations in certain sites in patients with Crohn's disease.

Arthritis↗
PubMed1976

Evidence for "deleted" or "silent" genes homozygous at the locus coding for the constant region of the gamma3 chain.

Three uncommon stable Gm haplotypes, Gm3;23;--, Gm1,2,17;..;-- and Gm1,17;..;-- have been transmitted through 3 generations of two related Lebanese and Syrian families. No pathological consequence was noted in seven individuals, aged 14--65, whose sera were deficient for all the allotypes carried by the IgG3 chains. Among the different genetic events which could have produced these haplotypes (alteration of a regulatory gene, point mutation, gene hybridization, gene deletion), it appears that a structural deletion is the most probable explanation. The observed data can be explained by either a partial or a total deletion of the constant portion of the IgG3 heavy chain.

Adolescent↗
PubMed1975

Does alpha-1-antitrypsin P1 null phenotype exist?

A second case of Pi null alpha-1-antitrypsin (AA) deficiency is described. In fact, the serum's subject contains 5 mug of AA per millilitre. With radiolabelled specific antibodies, it is possible to describe the Pi phenotype associated to this deficiency. The pattern which is obtained is like the ordinary Pi M, but 500 times lower than normal values. In contrast to a common deficient variant (ZZ or MZ), the subject tissues do not contain periodic acid-schiff positive inclusion bodies. The "normal" pattern obtained after antigen-antibody crossed electrophoresis, would be in favour of a deficient anomaly hereditarily transmitted.

Alleles↗
PubMed1975

Gm and Inv allotypes in premature infants.

Using haemagglutination inhibition tests specific for Gm allotypes and similar tests for IgG4, the placental transfer of the four IgG subclasses from mother to foetus has been confirmed. The Gm phenotype of a cord serum is often identical to that in the corresponding maternal serum. However in 31 cases out of the 90 tested, Gm allotypes were present in the cord serum that were not present in the maternal serum. These allotypes produced by the foetus in utero are dependent on a paternal gene. The logarithm of the IgG level increase proportionately with gestational age (r = 0.59 p less than 0.001).

Female↗
PubMed1975

Heterozygous alpha 1-antitrypsin deficiency and cirrhosis in adults, a fortuitous association.

Pi (protease inhibitor) genotype was determined in 394 healthy blood-donors, 132 adult patients with alcoholic cirrhosis, and 37 adult patients with cryptogenic cirrhosis. The frequency of the heterozygous genotype with a single allele Pi Z (heterozygous alpha 1-antitrypsin deficiency) was not different in blood-donors and in patients with cirrhosis. This finding suggests that the association of this heterozygous genotype with cirrhosis is not causal but fortuitous and that this heterozygous genotype does not increase susceptibility to cirrhosis due to other causes, in particular alcoholism.

Adult↗
PubMed1975

Immunochemical and biochemical study of a human Fcmu-like fragment (mu-chain disease).

An abnormal protein, from a petient with mu-chain disease has been studied: protein BUR. It is devoid of the F (ab'')2 mu fragment; molecular weight determinations and immunological data identify the protein as a F(c) 5 mu fragment. Similarly, carbohydrate determinations and proteolysis experiments relate it to a Fcmu fragment. Nevertheless, the protein, which tontains J-chain, lacks the entire covalently bonded structure of the F (c)5mu fragment. C-terminal analysis shows a tyrosine residue identical to the C-terminal amino acid of mu-chains. Sequence of the N-terminal region determined for 15 residues shows identity with sequence 338-352 and sequence 333-347 of two entire mu-chains previously studied. The relation of BUR to other heavy chain disease proteins is discussed.

Amino Acid Sequence↗
PubMed1975

[Deficiency of alpha-1-antitrypsin and the allele Pi nul].

Alpha-1-antitrypsin is a glycoprotein in human serum that inhibits several proteases. It is a polymorphic protein. A single autosomal locus (Pi), with multiple codominant alleles is responsible of the synthesis of alpha-1-antitrypsin. Of particular interest are alleles that lead to lower than normal concentrations of alpha-1-antitrypsin in serum, namely, PiS, PiP and PiZ. Some of these subjects carry a high risk of developing chronic obstructive pulmonary disease, especially when they are homozygotes for PiZ. In children, cirrhosis of the liver are also found in association with homozygosity for PiZ. recently, TALAMO discovered a subject whose serum contained no alpha-1-antitrypsin; this was the first case of total deficiency, and the patient carried a double dose of the so-called Pi--allele (Pi nul). We were able to demonstrate that a single dose of this allele exists in three families which we have studied in this paper. In a fourth family, the propositus carries Pi-- in duplicate. We report here the second case of the strange homozygous phenotype, Pi--. Surprisingly, we have found that alpha-1-antitrypsin is not completely absent in this serum; its concentration is 200 times lower than normal (less than 10 microgrammes per ml). At the moment, the existence of the Pi-- allele is obvious, but the significance of this small quantity of alpha-1-antitrypsin in the serum of such a patient remains unknown.

Adolescent↗
PubMed1975

Definition in man of a polymorphic system of the normal colonic secretions.

A study conducted in 30 normal human colons, obtained from cadaveric kidney donors, has evidenced the presence of two polymorphic antigenic specificities, W and Z, in the secretory cells of the colon mucosa. Three phenotypes have been demonstrated so far: W-Z- (frequency: 0.17), W-Z+ (frequency: 0.23), and W+Z+ (frequency: 0.60). Specific anti-WZ and anti-W alloantibodies, independent of anti-A and B agglutinins, were found in normal sera from blood donors. No apparent correlation was found between the WZ specificities and the ABH Lewis specificities, the other blood group systems specificities, and the leucocyte group (HL-A) specificities.

Blood Group Antigens↗