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Biomedical subjects

T Cohen

Publications and source records attributed to T Cohen.

At least 91 records · Page 5Linked to original sources
PubMed1987

Trisomy 13 in monozygotic twins discordant for major congenital anomalies.

The occurrence of trisomy 13 in twins is very rare. We report a pair of genotypically identical twins with trisomy 13 discordant for major anomalies. This case contributes to the already published data on the contribution of non-genetic factors to the aetiology of congenital malformations in monozygotic twins.

Abnormalities, Multiple↗
PubMed1986

Genetic control of HLA-linked immune responsiveness to (H,G)-A-L.

Fifty-three donors belonging to seven families were tested for their immune response potential to (H,G)-A-L. Most of these donors had been previously tested for their ability to respond to (T,G)-A-L and were all HLA typed as well. The heredity of the ability to respond to (H,G)-A-L by the production of an antigen-specific helper T cell factor is compatible with an autosomal dominant trait linked to HLA. The genotype of an HLA-A/B recombinant individual suggested that a gene controlling the immune response to (H,G)-A-L is linked to HLA-A. Lod scores also suggested a linkage between immune response potential to (H,G)-A-L and HLA-A. The different patterns of responses to (T,G)-A-L and (H,G)-A-L observed in many individuals are compatible with the notion that separate loci are governing the immune responses to the two synthetic polypeptides.

Female↗
PubMed1986

Immunogenetics of rheumatoid arthritis in Israel.

In an attempt to study the variation of associations between HLA and rheumatoid disease a population of 44 Ashkenazi and 29 non-Ashkenazi patients with Rheumatoid Arthritis were tested for HLA-A, B, C and DR antigens and compared with the relevant control groups. In contrast to the results obtained in Middle European or North American Caucasians, Rheumatoid Arthritis in Israel is not associated with B15 and Cw3, indicating that it is very unlikely that B- and C-locus antigens are involved in coding for disease susceptibility for RA. The allele DR4 which is found associated with RA in almost all populations tested so far was in the total patient group (47.9%) slightly but not significantly more frequent than in the control group (38.3%). This difference was entirely due to a nonsignificant increase in the frequency of DR4 in the Ashkenazi patients (54.5%) compared to controls (40%), while the frequency of DR4 in non-Ashkenazi patients and controls was virtually identical (38.0% vs 36.7%). Another surprising finding was that the frequency of HLA-DR1, which has been reported to be increased in different populations of patients with RA was found to be completely normal in the present study on Israeli patients. The alleles of the Bf and the GLO system did not show any significant difference between patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Antinuclear↗
PubMed1986

Genetic heterogeneity in Gaucher disease.

Considerable clinical variability occurs in adult Gaucher disease type I and three main subtypes may be delineated: a very mild form, a severe form, and a moderate form which itself presents various clinical manifestations. A study based on 25 families from our clinic and a review of published reports showed that when both parents were heterozygous and more than one child was affected with Gaucher disease type I, there was always intrafamilial similarity concerning the three subtypes. In families where one parent and at least one child were affected, variability in the clinical subtype of Gaucher disease type I might occur among the affected members of the family. We propose that the three different clinical subtypes of this disease reflect the genetic heterogeneity of two alleles, G1a and G1b and the three corresponding genotypes represent the three different subtypes of the disease.

Gaucher Disease↗
PubMed1986

Pilot study of the efficacy of spent grain dietary fiber in the treatment of constipation.

Spent grain is the crude fiber obtained by decanting the fermented distillate of barley. The spent grain was processed to yield dietary fiber composed of: cellulose and hemicellulose 65.6% (by weight), lignin 5.2%, pectin 2.2%, protein 10.9% and lipid 8.0%. Biscuits and scones were prepared by 25% substitution of wheat flour by fiber, yielding 7 to 8 g fiber per biscuit/scone. Nineteen ambulatory patients with chronic, laxative-dependent constipation were treated in a pilot study for 4 weeks with 20 to 25 g fiber daily. Fifteen patients (79%) showed improvement in some or all of five factors, while four patients were largely unresponsive to fiber. Specific symptoms improved as follows: bowel movement frequency in 15 patients (79%), flatulence in 12 (63%), abdominal pain in 10 (53%), stool consistency in 8 (42%) and laxative dependence in 14 (74%). A 4-week post-treatment follow-up showed a return to prefiber status in 11 of 13 improved subjects. This preliminary study suggests a role for spent grain fiber in the treatment of constipated patients, and a comparative study with placebo and wheat fiber is now warranted.

Adult↗
PubMed1985

Background allelic variants in normal hemopoietic cells and Bloom's syndrome erythrocytes and the possible implication of somatic crossingover.

The existence of rare cells with blood group A or B phenotype among the red cells of AB heterozygotes is a well-known phenomenon. However, its origin remains unclear due to methodological problems. A direct quantitation of non-B and non-A erythrocytes in A1B donors revealed minor populations of only-A and only-B cells, respectively, both in a frequency of 10(-3). Null cells comprise, at the most, a fraction of about 5 X 10(5). In order to discriminate between somatic crossingover (SCO) and gene inactivation as the underlying mechanism, three individuals were selected who were double heterozygotes for the blood group (AB) and the linked locus of adenylate kinase (AK-2-1). Separation of cells with A or B phenotypes did not result in cosegregation of the AK isoenzymes. Thus, the variant blood group phenotypes represent the normal frequency of allelic silence, not the product of SCO. This sets a background variant level for the estimation of somatic recombination in blood cells from normal donors. Determination of variant phenotypes in a Bloom's syndrome patient, heterozygous for AB, gave a frequency six times higher than the value of normals. It is suggested that this elevated figure might indicate the frequency of SCO, which is known to be higher in Bloom's syndrome.

ABO Blood-Group System↗
PubMed1985

HLA-linked immune responsiveness to (T,G)-A-L: a family study.

The heredity of the immune response potential to the synthetic polypeptide poly(LTyr,LGlu)-poly(DLAla)-poly(LLys) [(T,G)-A-L] and its possible linkage to the major histocompatibility complex of man were studied in 24 families. Peripheral blood lymphocytes (PBL) obtained from 174 donors belonging to 24 unrelated families were educated to (T,G)-A-L on autologous antigen-pulsed adherent cells. The supernatants obtained from these activated PBL were tested for their antigen-specific helper activity in an in vitro antibody production system. All donors were typed for their HLA haplotypes. The results obtained indicated that the ability to respond to (T,G)-A-L by production of an antigen-specific T cell helper factor is inherited as an autosomal dominant trait linked to the responder HLA haplotype.

Alleles↗
PubMed1984

Familial hereditary thrombocytopenia and HLA.

Three generations of a Jewish family with hereditary thrombocytopenia (HT) are described. The disease was manifested clinically by mild bleeding tendency since infancy. Circumcision, however, did not result in excessive bleeding. HLA study in this family indicated that the HT locus is not linked to HLA.

Adult↗
PubMed1984

Genetic polymorphisms among Bukharan and Georgian Jews in Israel.

Bukharan and Georgian Jews have lived in central Asia for many centuries. Approximately 30,000 Bukharan and 37,000 Georgian Jews lived in their respective countries within the USSR between 1920 and 1960. Genetic markers of blood--blood groups, isoenzymes, HLA antigens, and gamma and kappa chain allotypes--were tested in blood samples from 113 Bukharan and 134 Georgian Jews living in Israel. Estimates of inbreeding were low: alpha = 0.0088 for Bukharan and alpha = 0.0011 for Georgian Jews. G6PD deficiency was relatively rare in Bukharan (2.2%) and in Georgian Jews (6.0%), when compared to other Jews in the area. Both populations showed frequencies of some markers similar to that of other Jewish populations, but frequencies of several markers were extremely high or low. Bukharan Jews showed very high frequencies of B(0.243), cDe (0.122), JkA (0.705), HLA-A29 (0.167), A30 (0.116) and B7 (0.124), and AcPA (0.451) and very low ones of O(0.518), CDe(0.422), AcPB (0.513) and GLO1 (0.140). Very high frequencies in Georgian Jews were observed for cDE (0.189), HLA-A3 (0.194), Bw35 (0.300) and GLO1 (0.367). Yet the greatest difference between both populations was in African characters. While in Bukharan Jews Fy was very frequent (0.146) and cDe was the highest observed among Jews (0.122), neither of these markers was detected among the Georgian Jews tested. Yet, another African character, the Gm1,5,10,11,13,14,17,26 haplotype, occurred in both populations (0.028 and 0.042 in Bukharan and Georgian Jews, respectively). Distance measures for Bukharan, Georgian, Iranian, Cochin, and Libyan Jews based on 13 polymorphic loci showed the greatest distance between Cochin Jews and the other populations and the smallest distance between the Georgian and Iranian Jews.

Blood Group Antigens↗
PubMed1984

Is predisposition to pemphigus vulgaris in Jewish patients mediated by HLA-Dw10 and DR4?

Twenty-one Israeli Jewish pemphigus vulgaris (PV) patients were studied for the HLA-D lymphocyte defined determinants and the serologically defined antigens of the HLA-A, B, and DR series. HLA-D typing revealed that Dw10 is significantly associated with PV: 86% of patients vs 18% of controls carried Dw10, and DR4 was present in 86% of patients as compared to 38% in the controls. The most striking observation was that all Dw10 positive patients were also positive for DR4, and no other patient carried DR4 alone. The relative risk for a Dw10-DR4 carrier to develop PV was estimated at 31.9, higher than that observed for Dw10 alone (RR 26.7) or DR4 alone (RR 9.6). Probably HLA-Dw10 predisposes for pemphigus vulgaris.

Epitopes↗