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Biomedical subjects

T Cohen

Publications and source records attributed to T Cohen.

At least 145 records · Page 8Linked to original sources
PubMed1979

Relief of polarity in E. coli depleted of 30S ribosomal subunits.

Escherichia coli was depleted of ribosomes by a thermal shock at 47 degrees C which quantitatively destroyed the 30S ribosomal subunits. During recovery in minimal medium at 30 degrees C RNA is synthesized while protein synthesis resumes only after about 90 min. It is shown that lac mRNA is synthesized in the complete absence of ribosomal activity and hence RNA synthesis is not coupled to protein synthesis. Lac mRNA from a series of lac nonsense mutants was examined in both heated and untreated cells. It was found that the polar effect of nonsense mutation is relieved in the absence of ribosomes and that this relief is due to the synthesis of larger mRNA molecules. Since Rho remained active in thermally treated cells, premature termination at secondary signals within the lac operon must also depend on the presence of active ribosomes.

Escherichia coli↗
PubMed1979

Amelogenesis imperfecta among Israeli Jews and the description of a new type of local hypoplastic autosomal recessive amelogenesis imperfecta.

Amelogenesis imperfecta (AI) was detected in nine of 70,359 school children surveyed, a prevalence approximating 1:8,000. Of these cases, eight were the hypoplastic type and one the snow-capped hypomaturation type. Family studies demonstrated that hypoplastic AI was an autosomal dominant trait in two children and an autosomal recessive in six. Of three additional families referred to our clinic, two had autosomal recessive hypoplastic AI and one the hypocalcified type, inherited as an autosomal dominant trait. In four families, a new type of local hypoplastic autosomal recessive AI was observed, characterized by horizontal pitting and grooving more pronounced in the middle third of the crowns of most teeth in both dentitions.

Adolescent↗
PubMed1979

The Duffy blood group system in Israeli Jews and Arabs.

The distribution of the Fy gene was studied in 1,207 Israeli Jews and 509 Arabs. The Fy(a--b--) phenotype (FyFy) was observed in Moslem, Christian and Druze Arabs, and in Jewish immigrants from Yemen and Iraq, but not in Sephardi or Ashkenazi Jews. The Fy gene frequencies in Arabs and Jews were compatible with historical evidence of interactions with native African and admixed regional populations. Compared with Rho (cDe) and Jsa, Fy(a--b--) is a more useful genetic marker for recognizing African admixture in Middle Eastern populations.

Blood Group Antigens↗
PubMed1979

Chrome sensitivity in Israel.

Fifty-two Israeli Jewish patients suffering from chrome sensitivity (C.S.) were investigated with regard to their ethnic origin, age of onset of the dermatitis, occupational history and socio-economic level. Forty-eight patients suffering from various skin conditions and drawn from the outpatient dermatological clinic were used as controls. The socio-economic status of C.S. patients was found to be very low, regardless of ethnic origin. Ninety-four percent of the patients were non-Ashkenazi Jews and a significantly increased proportion of those (24%) were of Kurdish descent. There were no major differences in their occupations. Patients of Kurdish origin manifested the disease at a significantly earlier age than other non-Ashkenazi patients, although the socio-economic conditions of the different ethnic groups of patients were similar.

Adolescent↗
PubMed1979

Sib risk of neural tube defect: is prenatal diagnosis indicated in pregnancies following the birth of a hydrocephalic child?

Recurrence frequencies of central nervous system malformations in sibs of probands with anencephalus or spina bifida range between 1% and 7%. The frequency of hydrocephalus among sibs of such probands is low (0.21%) but, nevertheless, is increased 2 to 5-fold when compared to general population frequencies. Anencephalus and spina bifida cystica were observed in 1.65% of sibs of children with hydrocephalus, a 2- to 8-fold increased over the population frequencies. These data indicate that some aetiological factors may be common to all three malformations. The risk figure of 1.65% for anencephalus and spina bifida in sibs born after the birth of a hydrocephalic proband constitutes sufficient indication for prenatal diagnosis by alphafetoprotein determination of the amniotic fluid.

Anencephaly↗
PubMed1979

Gastrointestinal bleeding in aortic stenosis.

Gastrointestinal bleeding in aortic stenosis is an uncommon condition but when present it is often undiagnosed. The usual radiological proceedures fail to demonstrate the source of bleeding. Mesenteric angiography, however, will identify the lesion. The lesion is usually a vascular malformation located in the right colon. The angiodysplasia may also occur in other parts of the gastrointestinal tract. We have encountered five patients with aortic stenosis who had multiple massive hemorrhages of the lower gastrointestinal tract who defied diagnosis by the conventional methods. Mesenteric angiography, however, disclosed the orgin of the bleeding. In four patients vascular malformations were found in the right colon and one in the jejunum. Right hemicolectomy and partial jejunectomy resulted in a cure in all.

Aged↗
PubMed1979

Absence of association between HLA antigens and primary open angle glaucoma in Israel.

HLA antigens of the A and B loci were determined in 57 Israeli patients with primary open angle glaucoma (POAG) presenting visual field loss and in 715 normal control subjects. The glaucoma patients and control subjects were non-related and randomly selected from the Jewish Israeli population. Frequencies of HLA antigens among the POAG patients showed no differences from those observed in the control subjects. Similar results were observed for all patients as well as within subgroups of the patient population as defined by origin. Thus, the association reported between B7 and/or B12 and POAG in white and black Americans could not be confirmed in an Israeli population.

Adult↗
PubMed1979

Juvenile diabetes mellitus.

Population studies in Israel have shown that Jews born in Europe or America have the highest prevalence of juvenile diabetes mellitus and Jews born in Asia or Africa, the lowest. The rate in the Israel born, regardless of the father's place of birth, is intermediate between those of the other two groups. The rates for the group from Europe/American and for the Israel-born group increased during the years 1963-68, while that for the Asia/Africa group did not change. It is speculated that the differences in the rates of juvenile diabetes mellitus are related to different frequencies of certain HLA antigens in the different groups or to different associations with susceptibility genes to juvenile diabetes.

Adolescent↗
PubMed1978

A genetic study of Behçet disease in Israel.

The frequency of HLA-B5 in 24 Israeli Behçet disease (BD) patients from various subpopulations was significantly greater than in 615 control individuals (P less than 0.003). The relative risk for a B5 carrier to develop BD was calculated to be 5.0. Six patients were offspring of consanguineous marriages, which is not unexpected in the populations studied. Five of the patients had only one HLA-B antigen, which in four cases was B5. Two of the latter were B5 homozygotes, indicating a possible greater susceptibility. This study confirms the reported association between BD and HLA-B5 in a populationnot previously investigated. Furthermore, these data support the suggestion that B5 is associated with BD in populations deriving from the Mediterranean Basin, the Middle East and Far East.

Adolescent↗
PubMed1977

Selective hypoaldosteronism in Iranian Jews: An autosomal recessive trait.

A salt-wasting syndrome associated with high plasma renin activity and inappropriately low aldosterone levels was observed among eight Jewish families from Iran. Aldosterone deficiency was due to an inborn error selectively involving the terminal portion of the bio-synthetic pathway and characterized by an enzymic block in the conversion of 18-hydroxy-corticosterone to aldosterone. The analysis of the eight pedigrees, including 12 affected children, shows a high coefficient of inbreeding. Genetic analysis, by two independent methods, strongly suggests an autosomal recessive mode of transmission of the syndrome.

Aldosterone↗
PubMed1977

HLA B27 and ankylosing spondylitis in the Israeli population.

The distribution of 24 HLA antigens of the A and B loci was investigated in 38 Israeli ankylosing spondylitis (AS) patients of various ethnic origins. This was compared with the distribution in rheumatoid arthritis (RA) and osteoarthritis (OA), as well as in 456 controls representing the Jewish population and 260 controls representing the Arab population. Included in the study were Ashkenazi Jews and non-Ashkenazi Jews, as well as Moslem and Christian Arabs. The frequency of HLA B27 among AS patients (79 per cent) was significantly greater (P less than 10(-10)) than among the controls (three per cent). Ashkenazi Jews showed a higher relative risk than non-Ashkenazi Jews and Arabs. Six of the AS patients were offspring of consanguineous marriages, but this was not higher than expected and therefore no indication for rare recessive genes contributing to the disease could be demonstrated. This study confirms the association between AS and B27, and extends our knowledge to the heterogeneous population of Israel not previously investigated. A significant but weak association of B27 with RA was noted. No correlation of other HLA antigens with RA or OA was observed.

Adult↗