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Biomedical subjects

J Soh

Publications and source records attributed to J Soh.

29 records · Page 2Linked to original sources
PubMed1994

Identification and sequence of an accessory factor required for activation of the human interferon gamma receptor.

Human chromosomes 6 and 21 are both necessary to confer sensitivity to human interferon gamma (Hu-IFN-gamma), as measured by induction of class I human leukocyte antigen (HLA) and protection against encephalomyocarditis virus (EMCV) infection. Whereas human chromosome 6 encodes the Hu-IFN-gamma receptor, human chromosome 21 encodes accessory factors for generating biological activity through the Hu-IFN-gamma receptor. Probes from a genomic clone were used to identity cDNA clones expressing a species-specific accessory factor. These cDNA clones are able to substitute for human chromosome 21 to reconstitute the Hu-IFN-gamma receptor-mediated induction of class I HLA antigens. However, the factor encoded by the cDNA does not confer full antiviral protection against EMCV, confirming that an additional factor encoded on human chromosome 21 is required for reconstitution of antiviral activity against EMCV. We conclude that this accessory factor belongs to a family of such accessory factors responsible for different actions of IFN-gamma.

Amino Acid Sequence↗
PubMed1994

Sublocalization of the human interferon-gamma receptor accessory factor gene and characterization of accessory factor activity by yeast artificial chromosomal fragmentation.

A chromosomal fragmentation procedure was employed to produce a deletion set of yeast artificial chromosomes (YACs) from a parental YAC, GART D142H8, known to map to human chromosome 21q and to encode the human interferon-gamma receptor (Hu-IFN-gamma R) accessory factor gene as well as the phosphoribosylglycinamide formyltransferase (GART) gene. When expressed in Chinese hamster ovary cells, these deleted YACs retain accessory factor activity, as judged by major histocompatibility complex class I antigen inducibility, until the deletions from the acentric end exceed 390 kilobases (kb). Therefore, the accessory factor (AF-1) gene can be localized to a 150-kb region at the left (centric) end of the parental 540-kb GART YAC. Cells containing functional YACs are also able to induce the ISGF3 gamma and gamma-activated factor (GAF) transcription factors, but were not protected against encephalomyocarditis virus (EMCV) upon treatment with Hu-IFN-gamma. Therefore, the Hu-IFN-gamma R and the AF-1 are sufficient for some, but not all, of the actions of Hu-IFN-gamma. We postulate that an additional accessory factor (AF-2) required for antiviral activity against EMCV is encoded on chromosome 21q.

Acyltransferases↗
PubMed1994

Generation of random internal deletion derivatives of YACs by homologous targeting to Alu sequences.

To facilitate the manipulation of human genomic DNA in yeast artificial chromosome (YAC) clones, a plasmid to integrate the selective marker for antibiotic G418 resistance into YACs and to delete some of the human DNA fragments from YACs was constructed. The linearized integration/deletion plasmid, which contains Alu family sequences at both ends, can recombine with YACs containing human repetitive sequences via homologous recombination. The homologous recombination results in a random integration of the antibiotic G418-resistant gene into a human genomic Alu sequence, and in most cases, an internal deletion within the YAC. The YACs with internal deletions can be useful to identify the location of the genes if they produce functional knockouts. In those cases when the integration/deletion event disrupts the integrity of the gene so it no longer can produce a viable and functional mRNA in fused eukaryotic cells, the site of integration in the YAC thus serves as a marker for the inactivated gene. In this report we describe a model system to locate specific genes in YACs.

Animals↗
PubMed1993

Identification of a yeast artificial chromosome clone encoding an accessory factor for the human interferon gamma receptor: evidence for multiple accessory factors.

Human chromosomes 6 and 21 are both necessary to confer sensitivity to human interferon gamma (Hu-IFN-gamma), as measured by the induction of human HLA class I antigen. Human chromosome 6 encodes the receptor for Hu-IFN-gamma, and human chromosome 21 encodes accessory factors for generating biological activity through the Hu-IFN-gamma receptor. A small region of human chromosome 21 that is responsible for encoding such factors was localized with hamster-human somatic cell hybrids carrying an irradiation-reduced fragment of human chromosome 21. The cell line with the minimum chromosome 21-specific DNA is Chinese hamster ovary 3x1S. To localize the genes further, 10 different yeast artificial chromosome clones from six different loci in the vicinity of the 3x1S region were fused to a human-hamster hybrid cell line (designated 16-9) that contains human chromosome 6q (supplying the Hu-IFN-gamma receptor) and the human HLA-B7 gene. These transformed 16-9 cells were assayed for induction of class I HLA antigens upon treatment with Hu-IFN-gamma. Here we report that a 540-kb yeast artificial chromosome encodes the necessary species-specific factor(s) and can substitute for human chromosome 21 to reconstitute the Hu-IFN-gamma-receptor-mediated induction of class I HLA antigens. However, the factor encoded on the yeast artificial chromosome does not confer antiviral protection against encephalomyocarditis virus, demonstrating that an additional factor encoded on human chromosome 21 is required for the antiviral activity.

Animals↗
PubMed1993

[Clinical experience of endopyelotomy].

From July 1986, percutaneous endopyelotomy was performed on a total of 12 patients (13 kidneys) including 8 males and 4 females with ureteropelvic junction (UPJ) obstruction. Of the 13 kidneys, 9 had primary UPJ obstruction and 4 had secondary UPJ obstruction. A rigid urethrotome (cold knife) was employed in 12 cases and a flexible electorotome (hot knife) in one case. A stent ureteral catheter was placed for 3 to 31 weeks after the procedure. The outcome was evaluated by radiography and urodynamic examinations. A successful outcome was obtained in 8 of 9 kidneys with primary UPJ obstruction and in 1 of 4 kidneys with secondary UPJ obstruction. These findings suggest that percutaneous endopyelotomy is useful in the treatment of primary UPJ obstruction.

Adolescent↗
PubMed1990

Hybrid selection of mRNA with biotinylated DNA.

A novel, convenient, and highly efficient hybrid selection procedure is described. The method utilizes the polymerase chain reaction (PCR) in which one of two primers is biotinylated at the 5'-terminus. The concentration of the biotinylated primer is 100 times that of the other to synthesize biotinylated single-stranded DNA (asymmetric PCR). After hybridization of the biotinylated DNA with mRNA in solution, streptavidin agarose is used to trap the hybrid duplex of mRNA.DNA-biotin onto the solid matrix. The selected mRNA is then eluted from the streptavidin agarose. The quantitative physical recovery of selected mRNA is about 70% with about 33% retention of biological activity.

Animals↗
PubMedDate not supplied

Effects of disruption of the mitochondrial electrochemical gradient on steroidogenesis and the Steroidogenic Acute Regulatory (StAR) protein.

The steroidogenic acute regulatory (StAR) protein, which mediates cholesterol delivery to the inner mitochondrial membrane and the P450scc enzyme, has been shown to require a mitochondrial electrochemical gradient for its activity in vitro. To characterize the role of this gradient in cholesterol transfer, investigations were conducted in whole cells, utilizing the protonophore carbonyl cyanide m-chlorophenylhydrazone (m-CCCP) and the potassium ionophore valinomycin. These reagents, respectively, dissipate the mitochondrial electrochemical gradient and inner mitochondrial membrane potential. Both MA-10 Leydig tumor cell steroidogenesis and mitochondrial import of StAR were inhibited by m-CCCP or valinomycin at concentrations which had only minimal effects on P450scc activity. m-CCCP also inhibited import and processing of both StAR and the truncated StAR mutants, N-19 and C-28, in transfected COS-1 cells. Steroidogenesis induced by StAR and N-47, an active N-terminally truncated StAR mutant, was reduced in transfected COS-1 cells when treated with m-CCCP. This study shows that StAR action requires a membrane potential, which may reflect a functional requirement for import of StAR into the mitochondria, or more likely, an unidentified factor which is sensitive to ionophore treatment. Furthermore, the ability of N-47 to stimulate steroidogenesis in nonsteroidogenic HepG2 liver tumor cells, suggests that the mechanism by which StAR acts may be common to many cell types.

Animals↗
PubMedDate not supplied

Efficacy of sildenafil as the first-step therapeutic tool for Japanese patients with erectile dysfunction.

The aim of this study was to assess the efficacy of sildenafil as the first-step tool for erectile dysfunction (ED) in Japanese males. Between March 1999 and March 2003, 281 patients were prescribed five tablets of sildenafil (50 mg) as the first step in the therapeutic management of ED. Of the 281 patients, 206 were evaluable patients. The overall success rate in achieving sexual intercourse in subjects after taking sildenafil was 77.2% (159/206), while 22.8% (47/206) were unsuccessful. The success rates in men with functional ED and organic ED were 91.4% (85/93) and 65.5% (74/113), respectively (P<0.0001). Overall, transient adverse effects of sildenafil occurred in 16 (8%) males. Intolerable adverse effects (edema and dizziness) occurred in only 1% of patients (2/206). Sildenafil citrate may be recommended as the first choice drug for ED because of its high success rate and low invasiveness.

Adult↗
PubMedDate not supplied

Efficacy of sildenafil for Japanese patients with audio-visual sexual stimulation (AVSS) test by the RigiScan Plus.

Sildenafil is most effective in men with mild-to-moderate ED, but not severe ED in Japan. In order to evaluate the efficacy of sildenafil, we conducted the present study using the AVSS test by the RigiScan Plus. The subjects were 56 patients (age: 34-82 years, mean: 60.5 years) with ED. The IIEF5 questionnaire and the AVSS test were conducted before and after administration of sildenafil. The penile rigidity could not be measured in 19 patients. Of these 19, sildenafil was effective in 7 and not effective in 12. The 7 cases in whom sildenafil was effective were all false-negatives. The sensitivity of sildenafil was 84%, and its specificity was 100%. This study suggests that the AVSS test by RigiScan Plus can objectively evaluate the efficacy of sildenafil, and shows potential for predicting that efficacy.

Adult↗
PubMedDate not supplied

Comparison of tympanometry and otoscopy in establishing pass/fail referral criteria.

Impedance tests, pure tone screening, and pneumatic otoscopy were performed on two groups of children. For the second group, two physicians, one an otolaryngologist and the other a pediatrician, performed the otoscopic examination. Agreement between tympanometry and otoscopy was not influenced by the presence or absence of acoustic reflexes or passing or failing the pure tone screening, but did depend on the criteria used in classifying the tympanograms. Tympanograms classified as having significant negative pressure were those showing the poorest agreement between tympanometry and otoscopy. Between examiners, agreement in otoscopic findings was generally poor. Results are discussed as they apply to establishing pass/fail criteria for screening with impedance.

Auscultation↗