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Y Tani

Publications and source records attributed to Y Tani.

At least 163 records · Page 9Linked to original sources
PubMed1994

Impaired intracellular transport contributes to partial thyroxine-binding globulin deficiency in a Japanese family.

We have previously reported a Japanese family manifesting partial TBG deficiency (TBG-PDJ). This variant was characterized by a decreased level of serum TBG concentration, heat lability, and normal isoelectric focussing pattern, but the affinity to iodothyronine is unknown. The TBG-PDJ gene possesses a single nucleotide substitution replacing the normal Pro363(CCT) with Leu(CTT); however, the precise mechanism that results in the reduction of the TBG concentration in the serum of the subjects harboring this mutation remains unknown. This was investigated in the current communication by expressing the complementary DNAs of TBG-PDJ and the common type TBG (TBG-C) in COS-1 cells. Pulse-chase experiments revealed impaired secretion of TBG-PDJ. TBG-C secretion into the medium was evident during 60 min of the pulse period and was almost completed by 12 h. On the other hand, TBG-PDJ was secreted slowly and continued to accumulate between 12-24 h of the chase period. The molecular mass of TBG-PDJ in the cell lysate was identical to that of TBG-C when estimated by gel electrophoresis (54 kilodaltons). The content of TBG-PDJ in the cell lysate decreased less rapidly than that of TBG-C, indicating that impaired TBG-PDJ secretion accounts for the partial TBG deficiency. Oligosaccharide units of intracellular TBG-C were resistant to endoglycosidase-H, but half of those of TBG-PDJ were sensitive to the enzyme digestion, suggesting partial retention of TBG-PDJ within the rough endoplasmic reticulum. Northern blot analysis revealed abundant messenger ribonucleic acid for the glucose-regulated protein-78, the level of which was 3.54-fold greater in the cells transfected with TBG-PDJ than in nontransfected COS-1 cells, whereas that in TBG-C-transfected cells was same as that in the nontransfected cells. Increased expression of glucose-regulated protein-78 together with the sensitivity to endoglycosidase-H suggests impairment of intracellular processing of TBG-PDJ. Our results indicate that the impaired intracellular transport of the TBG-PDJ molecule is the main cause of the reduced concentration of immunoreactive TBG in the serum of subjects harboring this TBG variant.

Base Sequence↗
PubMed1994

A novel type of life cycle "delayed homothallism" in Saccharomyces cerevisiae wy2 showed slow interconversion of mating-type.

Saccharomyces cerevisiae wy2 segregated to 2 mater and 2 non-mater in relation to mating ability. The non-mater segregants behaved as the normal type of homothallic life cycle. On the other hand, the mater segregants gradually formed spores during successive subcultures, indicating that slow interconversion of mating-type happened to occur during subcultures. We termed this novel type of life cycle "delayed homothallism". The results of complementation tests with standard ho strains and introduction of a wild type HO gene showed that delayed homothallism was caused by a defective HO gene. The amino acid sequence deduced from the nucleotide sequence of the wy2 HO gene differed from the wild type HO gene in three amino acid residues. In the carboxy terminus of HO protein, there are three repeats of cysteine and histidine that are postulated to play a role in binding of HO protein to DNA. However, wy2 HO protein lacked one such repeat at residues Cys470-His475, where His was replaced by Leu.

Amino Acid Sequence↗
PubMed1994

Effect of "Megafiller" insertion on the wear of composite resins.

We have previously reported that insertion of coarse particles of beta-Quartz Glass Ceramic Insert (Megafiller) into a composite resin markedly reduced the polymerization shrinkage of resin restorative materials. In this study, we examined the effects of Megafiller insertion on wear resistance evaluated by the glass beads abrasion test, and the conventional toothbrushing abrasion test. The depth of wear was determined by measuring the thickness of the specimen before and after the wear tests using a profile projector accurate to 1 micron. In general, the depth of wear of the composites was reduced by Megafiller insertion, but the differences in the depth of wear between composites with and without the Megafiller were not significant except for a few materials. There were slight differences in the wetness of Megafiller in some composite resins.

Acrylic Resins↗
PubMed1994

[Omental pedicle flap for chronic empyema].

We have used the omental pedicle flap (OPF) method to treat 10 patients with chronic empyema secondary to pulmonary tuberculosis. Since 1987 they included 9 men and one woman ranging from 48 to 70 years in age. Two patients were required re-operation because of residual bronchopleural fistulas, and the additional procedures (muscle plombage and thoracoplasty) performed in order to close residual dead space produced more severe thoracic deformity and pulmonary dysfunction. In our first successful case, complete thoracoplasty combined with the OPF method also produced pulmonary dysfunction. On the other hand, thoracic deformity was avoided in 3 other patients and 4 patients without thoracoplasty showed better pulmonary function postoperatively. A comparison of the re-operated patients with the successful cases highlighted two important points regarding the OPF method. One is the need for firm fixation of the OPF to a fistula. We usually place a muscular pedicle flap over the OPF, and add limited thoracoplasty as necessary. The other important point is the control of infection. Open window thoracostomy before the OPF method is effective in patients with active infection. The OPF method is an effective radical operation for severe empyema even when residual dead space is present, and it can also be applied to patients with poor pulmonary function.

Aged↗
PubMed1994

A statistical analysis of predictive factors of response to human lymphoblastoid interferon in patients with chronic hepatitis C.

OBJECTIVE: To determine markers predictive of effective interferon treatment for patients with chronic hepatitis C virus (HCV) infection, we studied 80 Japanese patients treated for 6 months with natural interferon-alpha. METHODS: Serum samples were tested for HCV RNA by two-stage polymerase chain reaction (PCR). HCV RNA were grouped into four genotypes by amplification of core-gene sequences by PCR with type-specific primers, and the level of HCV RNA was measured by competitive PCR. HCV RNA was detected in all patients before the interferon treatment. For the purposes of this study, a complete response was defined as the elimination of HCV RNA for at least 6 months after termination of the treatment. RESULTS: HCV RNA was eliminated from the sera of 27 patients (33.8%) at the termination of the interferon treatment, and the elimination was sustained throughout a 6-month follow-up (complete response). Four of eleven variables proved to be associated with a complete response when assessed by univariate analysis. With multiple logistic regression analysis assessment, however, only two variables (HCV RNA level (p < 0.001) and genotype (p = 0.048)) were significant. CONCLUSION: These results suggest that factors associated with the HCV infection are more important than patient characteristics for effective interferon treatment of patients with chronic HCV infection and that a low level of HCV RNA and HCV of genotype III are useful predictors of a complete response.

Adult↗
PubMed1994

Effectiveness of relative low-dose interferon treatment for patients with chronic hepatitis C.

To demonstrate effectiveness by relative low-dose of interferon treatment for patients with chronic hepatitis C, we investigated the histological activity index (HAI) score of liver tissue, hepatitis C virus (HCV) genotype by polymerase chain reaction (PCR) with type-specific primers, HCV RNA levels by competitive PCR, serum aminotransferase, sex, age, history of blood transfusion and history of hepatitis in patients with chronic hepatitis C prior to treatment. Twenty-two patients were treated with human lymphoblastoid interferon (3 MU daily, 2 weeks, 3 MU thrice a week, 6 weeks, 1.5 MU thrice a week, 16 weeks) for 24 weeks, of whom 10 (45.5%) were responders within a 6 month follow-up. HAI score before treatment was significantly lower in responders than in a combined group of relapse patients and nonresponders (7.5 +/- 3.4 vs. 12.0 +/- 3.1, p < 0.01). The prevalence of responders in patients with genotypes III and IV was significantly higher than in those with genotype II (85.7% vs. 21.4%, p < 0.05). HCV RNA level (logarithmic transformed copy per 50 microliter of serum) was significantly lower in responders than in a combined group of relapse patients and nonresponders (4.8 +/- 1.2 vs. 5.7 +/- 0.8, p < 0.05). In case of other pretreatment factors, there were no significant differences between responders and a combined group relapse patients and nonresponders. Thus severe histological changes in the liver, HCV genotype II and high HCV RNA levels are markers of unfavorable effects of interferon treatment for patients with chronic hepatitis C.

Adult↗
PubMed1993

Normal T cell receptor-mediated signaling in T cell lines stably expressing HIV-1 envelope glycoproteins.

A series of T cell lines transfected to stably express HIV-1 envelope (env) glycoproteins were analyzed for viability and for T cell signaling. One transfectant was distinguished by its stable expression of gp120 and gp41, whereas the remainder of the T cell lines were similar to previously reported env-expressing T cells in synthesizing predominantly unprocessed env glycoprotein gp160. All of the transfectants were additionally constructed to express tat and rev proteins. None of these cell lines displayed growth abnormalities or spontaneous cell fusion, although the cell line synthesizing env gp120/gp41 could be induced to fuse and die when cocultured with a second cell expressing surface CD4. A cell line expressing only gp160 and the transfectant expressing gp160, gp120, and gp41 could be triggered normally via CD3-cross-linking as measured by protein tyrosine phosphorylation and by the induction of the CD69 activation marker. At levels of env protein expression sufficient to mediate syncytium formation and to kill cells, these HIV-1 env transfectants displayed no intrinsic T cell signaling abnormalities, suggesting that mechanisms other than a direct intracellular action of the tat or env proteins may be contributing to the deficit in Ag-specific T cell activation described subsequent to HIV infection in vivo and in vitro.

CD4-Positive T-Lymphocytes↗
PubMed1993

Analysis of 6R- and 6S-tetrahydrobiopterin and other pterins by reversed-phase ion-pair liquid-chromatography with fluorimetric detection by post-column sodium nitrite oxidation.

A rapid and sensitive reversed-phase ion-pair liquid chromatographic system with fluorimetric detection by post-column sodium nitrite oxidation was established for measuring six pterin compounds (6R-5,6,7,8-tetrahydrobiopterin, 6S,5,6,7,8-tetrahydrobiopterin, 7,8-dihydrobiopterin, biopterin, pterin and D-neopterin). The coefficients of variation for these pterins were 0.705-3.714%, and the minimum detectable amount was ca. 10-20 pg at a signal-to-noise ratio of 3. A linear detector response was also verified. The concentrations of the pterin compounds in rat tissues were measured by the described method. Furthermore, by means of brain microdialysis, the output of pterin compounds from rat striatum was detected. Therefore, these results demonstrate that this system can be applied to analyses not only of various rat tissues but also of dialysates collected in vivo.

Animals↗
PubMed1993

Endomitotic diploidization of Saccharomyces cerevisiae by heat treatment during spore germination.

Diploid cells with ability to mate, hereafter referred to as diploid mater cells, were obtained at significant frequencies by the heat treatment of haploid spores at the early germination stage in Saccharomyces cerevisiae heterothallic strain CG5M (a/alpha diploid cells heterozygous for five auxotrophic markers). The highest frequency (ca. 11%) of diploidization was obtained from viable cells after heat treatment at 55 degrees C for 10 min when spores were precultivated for 30 min in liquid medium to initiate the germination. The diploid mater cells obtained were homozygous for mating type and for the auxotrophic markers. The diploidization of a spore is thus concluded to be due to endomitotic events in germinating heat-treated spores.

Diploidy↗
PubMed1993

Properties of isochorismate hydroxymutase from Flavobacterium K3-15.

Isochorismate hydroxymutase (isochorismate synthase, E.C. 5.4.99.6) catalyzes the interconversion of chorismic acid [1] and isochorismic acid [2]. The enzyme was extracted from a Flavobacterium K3-15 that overproduces vitamin K2 (i.e., menaquinones) and was purified to homogeneity. The N-terminal amino acid sequence and the mol wt (36,240 +/- 100 daltons) were determined by ms following SDS PAG electrophoresis. The enzyme was characterized (stability, cofactor requirement, isoelectrical point), and antibodies were raised which showed no cross reactivity with isochorismate hydroxymutase from Escherichia coli and Enterobacter aerogenes 62-1. The kinetic data of the enzyme are different from those observed for the corresponding enzyme from Escherichia coli and Galium mollugo.

Amino Acid Sequence↗
PubMed1993

Immobilization of isochorismate hydroxymutase. Comparison of native versus immobilized enzyme.

Partially purified isochorismate hydroxymutase (isochorismate synthase, E.C. 5.4.99.6) from Flavobacterium K3-15, a vitamin K overproducer, was immobilized on CNBr-activated Sepharose 4B, alkylamine glass substituted with glutardialdehyde, and aminohexyl Sepharose 4B substituted with glutardialdehyde. The immobilized enzyme exhibited a lower specific activity but a broader pH tolerance and a higher thermostability than the soluble enzyme. The stability of the enzyme was greatly increased by immobilization. Isochorismic acid, which is not commercially available, was prepared by a constant flow incubation.

Catalysis↗
PubMed1993

Degradation of a sodium acrylate oligomer by an Arthrobacter sp.

Arthrobacter sp. strain NO-18 was first isolated from soil as a bacterium which could degrade the sodium acrylate oligomer and utilize it as the sole source of carbon. When 0.2% (wt/wt) oligomer was added to the culture medium, the acrylate oligomer was found to be degraded by 70 to 80% in 2 weeks, using gel permeation chromatography. To determine the maximum molecular weight for biodegradation, the degradation test was done with the hexamer, heptamer, and octamer, which were separated from the oligomer mixture by fractional gel permeation chromatography. The hexamer and heptamer were consumed to the extents of 58 and 36%, respectively, in 2 weeks, but the octamer was not degraded. Oligomers with three different terminal groups were synthesized to examine the effect of the different terminal groups on biodegradation, but few differences were found. Arthrobacter sp. NO-18 assimilated acrylic acid, propionic acid, glutaric acid, 2-methylglutaric acid, and 1,3,5-pentanetricarboxylic acid. Degradation of the acrylic unit structure by this strain is discussed.

Acrylates↗
PubMed1993

High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as in monomeric forms in C. boidinii cells. The C. boidinii URA3 gene was overexpressed in C. boidinii on these CARS vectors. CARS1 and CARS2 were found to function as an autonomous replicating element in Saccharomyces cerevisiae as well. Different portions of the CARS1 sequence were needed for autonomous replicating activity in C. boidinii and S. cerevisiae. C. boidinii could also be transformed with vectors harboring a CARS fragment and the S. cerevisiae URA3 gene.

Acetates↗
PubMed1993

Sequence of a variant thyroxine-binding globulin (TBG) in a family with partial TBG deficiency in Japanese (TBG-PDJ).

Thyroxine-binding globulin (TBG) is the major transport protein of thyroid hormones in human serum. In this communication, we present a sequence abnormality of the TBG-gene in a Japanese family manifesting partial TBG deficiency (TBG-PDJ). The propositus was a male with a reduced concentration of TBG (3.2 micrograms/ml). Thyroid function tests suggested that the inheritance of this TBG abnormality was X-linked. The TBG exhibited increased heat-lability compared with the common type TBG (TBG-C). The isoelectric focusing pattern of this TBG molecule was indistinguishable from TBG-C. Genomic DNAs from white blood cells of four members of a TBG-PDJ family were subjected to polymerase chain reaction (PCR), and the products were sequenced. The sequencing of the entire coding exons and exon/intron junctions of TBG allele of the propositus revealed a single nucleotide substitution: CCT (proline) to CTT (leucine) at amino acid 363 of the TBG-C. The heterozygosity as revealed by the direct sequencing of the PCR product correlated with the TBG concentration in serum. The proline to leucine substitution may cause a change in the TBG tertiary structure and result in decreased heat stability, resulting in decreased TBG levels in the affected subjects.

Base Sequence↗