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Biomedical subjects

D Cohen

Publications and source records attributed to D Cohen.

At least 595 records · Page 33Linked to original sources
PubMed1985

Restriction fragment length polymorphism of the major histocompatibility complex of the pig.

Human HLA cDNA probes were used to analyze the restriction fragment length polymorphism (RFLP) of the SLA major histocompatibility complex in swine. Cellular genomic DNA from 19 SLA homozygous pigs representing 13 different haplotypes was digested with restriction endonucleases Eco R1, Hind III, or Bam H1, separated by electrophoresis, and transferred onto diazobenzyloxymethyl paper by the Southern blot technique. The blots were probed with 32P-labeled class I or beta-DR class II cDNA. Depending on the haplotypes and the endonucleases used, seven to ten restriction fragments hybridized with the class I probe, and five to seven with the beta-DR probe. Their sizes ranged from 3.4 to 22 kilobase-pairs. Few bands were common to all 13 haplotypes. With all but one haplotype, identical autoradiogram patterns were obtained from unrelated, but phenotypically SLA-identical pigs, suggesting that most of the RFLP revealed were controlled by the SLA region. Further polymorphism was found in a group of seven unrelated pigs which typed serologically as SLA A15 C1 B18 homozygotes but could be divided into two subgroups, with five animals in one subgroup and two in the other, when the genomic DNA was hybridized with the class I probe. When the class II beta-DR probe was tested on the same seven pigs, another subdivision was seen, and this correlated with MLR data. These results demonstrate that HLA class I and class II probes can be used to identify certain well-established SLA haplotypes and to identify subclasses within at least one SLA haplotype.

Animals↗
PubMed1985

Serological expression after sequential double transfection with purified HLA-A11 gene of mouse fibroblasts carrying human beta-2 microglobulin.

A genomic cosmid library constructed from DNA from a genotyped individual (JF = HLA-A11, Cw-, B38/A26, Cw7, B51) was screened for clones containing class I histocompatibility genes. Among these clones, one was found to carry a 4.8 kb Hind III fragment which is highly correlated with HLA-A11. This clone was used to transfect LMTK+ cultured mouse fibroblast transformants expressing human beta-2 microglobulin. The human beta-2 microglobulin heavy chain-associated determinant was positively detected by the M18 monoclonal antibody. HLA-A11 expression on these doubly transformed cells was specifically demonstrated by complement-dependent cytotoxicity with HLA-A11 + A3-specific but not with HLA-A3-specific monoclonal antibodies. Absorption studies with human alloantisera confirmed the presence on these cells of HLA-A11 determinants and of cross-reacting determinants which absorbed anti-HLA-A1 and -A3 alloantisera. The JF5-J27 transfected cell expressed both heavy and light chains of human class I histocompatibility genes.

Animals↗
PubMed1985

Analysis of the sheep MHC using HLA class I, II, and C4 cDNA probes.

Four cDNA probes for the human major histocompatibility complex (MHC) were used to investigate the sheep MHC, in conjunction with serological typing for ovine lymphocyte antigen (OLA). Lymphocytes from a family (two parents and five offspring) of Romanov sheep were subjected to genomic DNA digestion by the restriction endonuclease Eco RI, followed by gel electrophoresis. A single Southern blot representing all seven individuals was then consecutively hybridized with the class I, alpha-DC, beta-DR, and C4 probes, which were originally designed to identify HLA class I, class II (DC and DR), and C4 products, respectively. Using each of the three class I/class II probes, several bands showing DNA polymorphism were detected. The segregation of these bands in the five offspring exactly paralleled the OLA haplotype segregation established by serological typing. A further eight individuals carrying haplotypes which were phenotypically identical to those in the above-mentioned family showed bands in the corresponding positions when tested with the same three probes. Using the C4 probe, no polymorphism was detected in these fifteen individuals.

Animals↗
PubMed1985

Synthesis and biological activity of modified peptide inhibitors of angiotensin-converting enzyme.

A series of non-sulfhydryl modified dipeptides related to CI-906, CI-907, and enalapril was prepared in which various isosteric moieties (O, S, SO, SO2) have been substituted for the amino group and in which the proline residue has been replaced with various hydrophobic amino acids. The compounds were evaluated in vitro for inhibition of angiotensin-converting enzyme and in vivo for antihypertensive activity. Compound 7c, the most potent member of this series, had an in vitro IC50 of 1.4 X 10(-8) M and showed modest oral antihypertensive activity at 30 mg/kg in conscious, two kidney, one clip Goldblatt hypertensive rats. Structure-activity relationships are discussed.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

A systematic study of HLA class II-beta DNA restriction fragments in insulin-dependent diabetes mellitus.

DNA restriction fragments of the genes encoding HLA class II-beta antigens were compared in 34 patients with insulin-dependent diabetes mellitus and 34 HLA-DR-matched healthy individuals. Ninety-three fragments, determined by six restriction enzymes (EcoRI, EcoRV, HindIII, BamHI, Pvu II, and Taq I), were analyzed: (i) A DR Taq I 12.7-kilobase-pair fragment might be a marker for the extended haplotype HLA-B8, DR3. (ii) In controls, DR4 haplotypes are associated with two distinct clusters of DQ restriction fragments (DQR4 and DQR5). Almost all (94%) DR4 patients belong to the DQR4 and not to the DQR5 cluster. This suggests that, among HLA-DR4 haplotypes, only DQR4 haplotypes are involved in susceptibility to insulin-dependent diabetes mellitus. (iii) A DR Taq I 14.5-kilobase-pair fragment was found to be strongly associated with DQR4, mainly in DR3/DR4 heterozygous patients (P = 5 X 10(-4). However, these results must be interpreted with caution, taking into account the high number of statistical tests performed.

DNA Restriction Enzymes↗
PubMed1985

Exuberant restriction fragment length polymorphism associated with the DQ alpha-chain gene and the DX alpha-chain gene.

Cellular DNAs from individuals of 23 families were digested with five restriction endonucleases (Pvu II, EcoRI, HindIII, BamHI, and EcoRV) and then probed with a DX alpha-chain gene probe. Seventeen allogenotopes were observed, each of which could be assigned to a serologically defined haplotype by noting its segregation in families. Six sets of allogenotopes forming allelic series were noted. In comparison with restriction maps of the DQ alpha and the DX alpha regions, each of these series has been assigned to the DQ alpha or the DX alpha locus. Allogenotopes of the four DQ alpha series constitute three clusters correlating with the supertypic groups of class II histocompatibility antigens DQw1 (DR1, DR2, and DRw6), DRw53 (DR4, DR7, and DR9), and DR3 plus DR5 plus DR8. These 13 DQ alpha fragments constitute 22 different patterns. The two DX alpha series constitute two clusters, one of which is not found to be correlated strongly with DR specificities, whereas the other is correlated loosely (r = 0.45) with DR5 and DR7. This absence of strong linkage disequilibrium between the DX alpha series and the DR series contrasts with the DQ alpha series and suggests a recombination point between DQ alpha and DX alpha loci.

Alleles↗
PubMed1985

"Retroposon" insertion into the cellular oncogene c-myc in canine transmissible venereal tumor.

We examined by Southern blotting the state of the cellular oncogene c-myc in the dog transmissible venereal tumor. The tumor DNA contains a 16.8-kilobase pair (kbp) rearranged c-myc fragment in addition to the normal 15-kbp and 7.5-kbp fragments. We compared the structure of the cloned rearranged c-myc (re-myc) with that of a cloned normal c-myc and found that the rearrangement was due to the insertion of a 1.8-kbp DNA upstream to the first exon of c-myc. The inserted DNA is flanked by 10-base-pair direct repeats and contains a dA-rich tail, suggesting its origin from mRNA. Partial sequence of the inserted element showed 62% homology with the primate interdispersed Kpn I repetitive element. These results provide an example for the behavior of repetitive DNA sequences like the Kpn I family, as movable elements that can transpose nearby to oncogenes or other structural genes and perhaps affect their activity.

Animals↗
PubMed1985

The evaluation of radiographs of the nasopharynx.

Radiographs of the nasopharynx are sometimes misinterpreted because of poor technical quality. A simple method of interpretation is suggested based upon measuring the airway immediately behind the upper part of the soft palate. If it is narrower than the width of the soft palate it is considered as markedly obstructed. When narrower than half of the soft palate, it is severely obstructed. When it is the same width as the soft palate, it is not narrowed. One hundred and forty radiographs were evaluated by this method and by previously described methods. All methods showed good correlation and the present method is easy to use and easy to teach and has proven to be useful even in radiographs which other methods fail to interpret. The importance of evaluating the airway instead of the adenoidal thickness is stressed.

Adenoids↗
PubMed1985

A case-control study of maternal age in Alzheimer's disease.

A case-control study of maternal age as a risk factor for Alzheimer's disease was conducted in Washington state. Clinically diagnosed cases of Alzheimer's disease (n = 64) were identified from two sources, an outpatient clinic at the University of Washington and an organization of relatives of patients with Alzheimer's disease. Controls were spouses of the Alzheimer's disease cases and spouses of 87 patients with Parkinson's disease, also identified at the University of Washington. Mail questionnaires were sent to all subjects; responses were received for 90 cases and 96 controls, although nine of those cases, whose medical records of diagnostic evaluations were incomplete, were excluded. Among the 69 cases and 94 controls whose mothers' ages were known, there was no evidence that the mothers of cases were significantly older than the mothers of controls (chi-square test for trend, P = 0.82). These findings do not support the theory that persons born to older mothers are at increased risk of developing Alzheimer's disease.

Adult↗
PubMed1985

Molecular genetic analyses of the major histocompatibility complex in pig families and recombinants.

Five HLA probes, one corresponding to class I genes, two corresponding to distinct class II light chain genes, DR beta and DQ beta, and two to class II heavy chain genes, DR alpha and DQ alpha, were used to analyse the genomic DNA of the pig. Three informative SLA typed families and four SLA recombinants were studied by Southern blot analysis. About 16 restriction fragments, generated by EcoR1 or Hind III endonucleases, were revealed for each individual, either with the class I probe or the DR beta probe. The number of restriction fragments which hybridized with the other probes was generally lower. Several restriction fragment-length polymorphisms were found and these segregated with SLA haplotypes. The studies on SLA recombinants showed that SLA DR beta- and DQ alpha-like genes are probably tightly clustered within the SLA-D-MLR region.

Animals↗
PubMed1985

Day and full time psychiatric treatment: a controlled comparison.

Ninety-one patients admitted as emergencies, suffering from neurosis, personality disorder, or adjustment reaction, were randomly allocated to day hospital or to continued in-patient care. Follow-up was for up to one year. Clinical outcome was similar in the day care and in-patient groups, but patient satisfaction was significantly greater in day patients. Day hospital care was only about two-thirds of the cost of the cheaper of the two in-patient regimes, even though contact with it was on average twice as long as for in-patients.

Adjustment Disorders↗
PubMed1985

Induction of oestrus in the camel (Camelus dromedarius) during seasonal anoestrus.

Injection of 7000 i.u. PMSG induced oestrus in 7 camels during the last part of seasonal anoestrus. Mature follicles developed and a CL was formed after fertile mating. However, pregnancy was not maintained by Day 60 in the 3 females detected as pregnant by rectal palpation and increased progesterone concentrations at Day 50. A single male camel mated with 4 of the females 2-16 days after the PMSG injection, and 2 or 3 matings occurred. The failure of pregnancy after induction of oestrus and mating during seasonal anoestrus was probably due to inadequate luteal function.

Anestrus↗