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Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 541 records · Page 30Linked to original sources
PubMed1999

CAG repeat length in the androgen receptor gene of infertile Japanese males with oligozoospermia.

We analysed the CAG repeat length in exon 1 of the androgen receptor gene in 59 idiopathic Japanese infertile males with oligozoospermia; 36 fertile males were also analysed as controls. The number of CAG repeats in infertile males ranged from 14 to 32 (mean 21.2+/-4.2), whereas the number of CAG repeats in fertile males ranged from 16 to 31 (mean 21.4+/-3.5). Among infertile males, six possessed a short form of 14 CAG repeats and three possessed 15 CAG repeats. On the other hand, fertile males did not possess the short form of 14 or 15 CAG repeats. The incidence of infertile males with 14 and 15 CAG repeats was significantly higher (P<0.05) than that of fertile males. Although the sample size is small, the results suggest that the reduction of CAG repeats in exon 1 of the androgen receptor is closely related to impaired spermatogenesis in infertile Japanese males.

Adult↗
PubMed1999

Monkey hepatocytes efficiently express tissue factor pathway inhibitor (TFPI), in contrast with human and rat hepatocytes.

It has been reported that tissue factor pathway inhibitor (TFPI), a Kunitz-type protease inhibitor that regulates the extrinsic blood coagulation pathway, is not expressed in human, bovine, rabbit, or rat liver. Here, we found that TFPI is efficiently expressed in Macaque monkey liver. Monkey hepatocytes were identified as the expression cells by Northern blot analysis. The hepatocytes were stained with anti-human TFPI antibody, as were endothelial cells of the small vessels. We isolated and sequenced the 5'-flanking 1.4 kb regions of monkey and human TFPI genes, and found them to show 92.6% identity in their nucleotide sequences. We measured their transcriptional activities using a luciferase reporter gene and showed that the activity of the monkey TFPI gene is higher than that of the human gene in monkey primary hepatocytes. Although the binding motif of hepatocyte nuclear factor-1 is present only in the monkey gene, the site does not seem to be involved in the transcriptional activity. Mutagenetic analyses revealed that the region from -138 to +28 in the monkey gene is important for the expression of TFPI in hepatocytes. The present study indicates that the expression of the monkey TFPI gene is regulated by different mechanisms from the human TFPI gene.

Animals↗
PubMed1999

Identification and possible roles of three types of endopeptidase from germinated wheat seeds.

Little or no endopeptidase activity was detected in extracts of dry mature wheat seeds, but when they were allowed to imbibe water in darkness, the activity expressed per seedling increased notably after d 1, reached a maximum on d 3 and then decreased. Two major endopeptidases, named WEP-1 and WEP-2, were present in the 50-70% saturated ammonium sulfate fraction of d-3 seedlings, and could be separated by hydrophobic column chromatography. WEP-1 was further purified and identified as a 31-kDa polypeptide that was immunoreactive to antiserum raised against REP-1, a major rice cysteine endopeptidase. Experiments with proteinase inhibitors revealed that WEP-1 and WEP-2 are cysteine and serine endopeptidases, respectively. The two enzymes differed in substrate specificity, pH dependence, and the ability to digest major wheat seed proteins. Determination of its amino-terminal amino acid sequence indicated the similarity of WEP-1 to other cereal cysteine endopeptidases which are involved in the digestion of seed storage proteins. The expression of WEP-1 in de-embryonated seeds was induced in the presence of gibberellic acid and its effect was eliminated by abscisic acid. In addition to WEP-1 and WEP-2, a legumain-like asparaginyl endopeptidase was identified in the extract of seedlings on hydrophobic chromatography. The asparaginyl endopeptidase may function in the early step of mobilization of wheat storage proteins in germinated seeds.

Amino Acid Sequence↗
PubMed1999

The structure and organization of two cysteine endopeptidase genes from rice.

REP-1 is a major cysteine endopeptidase that digests seed storage glutelin of rice. A cDNA clone (pRP60) for REP-1 and a cDNA clone (pRP80) for a related enzyme were previously isolated. The expression of both mRNAs is regulated by gibberellin. In this study, we revealed the structure and organization of Rep1 and RepA, genes corresponding to pRP60 and pRP80 mRNAs, respectively. Rep1 has no introns whereas RepA consists of five exons and four introns, and both genes exist as one copy gene in the rice genome. The gibberellin-responsive elements conserved in cereal alpha-amylase genes are not included in the 5'-upstream region of Rep1 or RepA. A molecular phylogenetic tree of plant cysteine endopeptidases was constructed, and their relationship was discussed.

Amino Acid Sequence↗
PubMed1999

Functional analysis of retrotransposons in pea.

The 5'-upstream regions of the plant active defense genes in pea (PSPAL2 and PSCHS1) exhibit significant nucleotide sequence identity to part of a copia-type retrotransposon. To characterize the retrotransposon in pea putative reverse transcriptase sequences (Psr) were amplified by PCR from cDNA prepared from protoplasts derived from pea suspension cultured cells. Psr genes can be classified into at least eight subgroups (A-H) according to their nucleotide sequence similarities. A subgroup PsrC was induced by the treatment of etiolated pea epicotyls with fungal elicitor within 30 min but was hardly induced by protoplasting of pea suspension cultured cells, whereas subgroups of PsrA and PsrB were highly induced by protoplasting. Interestingly, the retrotransposon sequence present at the 5'-upstream region of PSCHS1 which was induced by the treatment with fungal elicitor belonged to subgroup PsrC. The retrotransposon might play an important role in reorganization of the genes and optimization of the gene expression in response to various environmental stimuli such as an attack by phytopathogens or protoplasting.

5' Untranslated Regions↗
PubMed1999

Suppression of intracellular superoxide dismutase activity by antisense oligonucleotides causes inhibition of progesterone production by rat luteal cells.

Superoxide radicals are known to inhibit progesterone production by luteal cells and have also been reported to cause apoptosis in various cells. The corpus luteum has an antioxidant enzyme to scavenge superoxide radicals: copper-zinc superoxide dismutase (Cu, Zn-SOD). However, it remains unknown how the decrease in intracellular Cu,Zn-SOD activity influences luteal function. This study was therefore undertaken to investigate whether suppression of intracellular Cu,Zn-SOD activity inhibits progesterone production by rat luteal cells and causes apoptosis. To suppress intracellular Cu, Zn-SOD activity, dispersed rat luteal cells were incubated with Cu, Zn-SOD antisense oligonucleotides. The 48-h treatment with antisense oligonucleotides (10 microM) inhibited Cu,Zn-SOD activity by 50% and Cu,Zn-SOD mRNA level by 30%, whereas sense oligonucleotides used as the control had no effect. Progesterone concentration in the medium was significantly decreased by the 48-h treatment with antisense oligonucleotides in the presence of hCG, and this inhibitory effect was completely blocked by the simultaneous addition of N-acetyl-L-cysteine, an antioxidant. Treatment with antisense oligonucleotides caused no significant change in the percentage of apoptotic cells as morphologically evaluated by the nuclear staining with Hoechst dye. In conclusion, the decrease in intracellular Cu, Zn-SOD activities inhibits progesterone production by rat luteal cells, which may be mediated by superoxide radicals, suggesting that intracellular Cu,Zn-SOD plays important roles in the regulation of luteal function.

Animals↗
PubMed1999

Role of class I major histocompatibility complex-restricted and -unrestricted suppression of human immunodeficiency virus type 1 replication by CD8+ T lymphocytes.

CD8+ T lymphocytes of asymptomatic human immunodeficiency virus type 1 (HIV-1) carriers (ACs) are capable of suppressing HIV-1 replication in CD4+ peripheral blood mononuclear cells (PBMC) by a variety of known and unknown mechanisms. In the present study, cell contact-dependent, major histocompatibility complex type I (MHC I)-unrestricted, CD8+ cell-mediated suppression of HIV-1 LAI replication was detected. CD8+ PBMC of ACs suppressed HIV-1 replication more efficiently in MHC I-matched CD4+ PBMC than in mismatched cells. However, even when MHC I was totally mismatched, CD8+ cells still suppressed replication to a considerable extent in CD4+ PBMC. This MHC I-unrestricted, CD8+ cell-mediated HIV-1 suppression required cell contact and was not effective against cells of the established T cell line ILT-KK. In contrast, MHC I-restricted HIV-1 suppression by CD8+ T cells was detected when ILT-KK cells were used as a target. By using these systems, we examined MHC I-restricted and -unrestricted suppressive activities of CD8+ cells in various donors in more detail. Although both types of CD8+ cell-mediated HIV-1 suppression diminished at the advanced stage of the infection, MHC I-unrestricted suppression diminished earlier than MHC I-restricted suppression, in parallel with the decline in CD4+ T cells. These results suggest that suppression by the MHC I-restricted mechanism alone may fail to protect against CD4+ T-cell loss at the late stage of infection.

CD4-Positive T-Lymphocytes↗
PubMed1999

Effect of recombinant human platelet-derived growth factor-BB and bone morphogenetic protein-2 application to demineralized dentin on early periodontal ligament cell response.

The purpose of this study is to investigate the early responses of human periodontal ligament cells attached to recombinant human platelet-derived growth factor-BB and bone morphogenetic protein-2 applied EDTA-demineralized dentin. One hundred and seventy-four root-planed flat dentin blocks were prepared from the mid-third of periodontally diseased human tooth roots. After demineralization with 24% EDTA (pH 7.02) 120 dentin blocks were treated with 0.5 and 1 microgram/ml rhPDGF-BB, 1 and 3 micrograms/ml rhBMP-2 and only MEM as control (24/group). Human periodontal ligament cells (HPLC) were seeded on these dentin surfaces and incubated. The alkaline phosphatase (ALP) activity and protein concentration of the attached cell were assessed at d 2, 4 and 7. Fifty-four dentin blocks were seeded with HPLC after application of 1 microgram/ml rhPDGF-BB, 3 micrograms/ml rhBMP-2 and MEM (18/group) and then incubated. At d 2, 4 and 7, the attached cells were stained and counted under light microscope. The results showed a significant increase of protein concentration and cell number in PDGF-BB treated groups than control (p < 0.05, p < 0.01) but not the ALP activity, and a significant increase of ALP activity was observed in BMP-2 treated groups than control (p < 0.05) but protein concentration and cell number remained almost the same over time. Thus, rhPDGF-BB and rhBMP-2 application to EDTA demineralized dentin surfaces promote the early human periodontal ligament cell responses by increasing cell proliferation and differentiation, respectively, which would ultimately enhance periodontal regeneration.

Adolescent↗
PubMed1999

Regulation of the expression of serotonin N-acetyltransferase gene in Japanese quail (Coturnix japonica): I. Rhythmic pattern and effect of light.

Serotonin N-acetyltransferase [arylalkylamine N-acetyltransferase (AANAT); EC2.3.1.87] is the rate-limiting enzyme in melatonin synthesis, and its activity exhibits a diurnal rhythm similar to that of the melatonin content in the pineal gland and retina of Japanese quail. Studies were conducted to characterize the Japanese quail AANAT cDNA, and to evaluate the expression of AANAT mRNA in the pineal gland, the retina, and other peripheral tissues. The nucleic acid sequence of a 400 bp cDNA clone obtained by RT-PCR manifested 78 and 95% homology compared to the rat and chicken AANAT cDNA, respectively, while the deduced amino acid sequence homology was 82 and 99%, respectively. AANAT mRNA content in a single pineal gland or an aliquot of eye lysate was measured by a micro-lysate protection assay. The expression of AANAT mRNA in the pineal gland and the retina exhibited circadian rhythm with peak levels at night. AANAT mRNA was also detected in the testis, but did not display a rhythmic change over a 24 hr period. AANAT mRNA was not detected in other tissues studied. Darkness during the day did not increase the pineal AANAT mRNA levels. However, unexpected light-exposure for 2 hr just after lights-off blocked the increase in AANAT mRNA, and at midnight remarkably decreased AANAT mRNA by 50%.

Amino Acid Sequence↗
PubMed1999

Regulation of the expression of serotonin N-acetyltransferase gene in Japanese quail (Coturnix japonica): II. Effect of vitamin A deficiency.

Levels of serotonin N-acetyltransferase [arylalkylamine N-acetyltransferase (AANAT); EC2.3.1.87] mRNA, AANAT activity, and melatonin display a rhythmic pattern in both the pineal gland and the retina. It has been shown that vitamin A is required to maintain the rhythm of melatonin synthesis in the pineal gland of Japanese quail. To understand the mechanism underlying the direct relationship among these factors, we developed an assay system sensitive enough to determine AANAT mRNA, AANAT activity, and melatonin content from a single pineal gland of Japanese quail. Positive direct relationships were found among these three parameters. We next deprived Japanese quail of vitamin A by feeding them a vitamin A-free diet supplemented with retinoic acid, and examined the effects of vitamin A deficiency on the expression of AANAT mRNA in the pineal gland and the retina. Vitamin A deficiency reduced both the expression of AANAT mRNA and melatonin content in the pineal gland. Retinal AANAT mRNA rhythm disappeared in vitamin A-deficient quails. Moreover, the responsiveness of the pineal gland and the retina to light was reduced by vitamin A deficiency when compared with the control group.

Animals↗
PubMed1999

Infraposition of ankylosed permanent maxillary incisors after replantation related to age and sex.

The extent of infraposition of replanted and subsequently ankylosed permanent incisors was examined in a longitudinal study of 52 patients. Study cast models were made during the follow-up period. Infraposition was evaluated on frontal photos of the study cast models taken parallel with the occlusal plane. The extent of infraposition was defined as the difference between the position of the incisal edge of the replanted incisor and the adjacent non-injured incisor in apico-coronal direction, measured with a digital caliper at 50x magnification of the negatives. The precision of this measuring procedure was 2.9% and the accuracy 2.0%. Marked infraposition was identified if the tooth was traumatized before the age of 16 in boys and before the age of 14 in girls. In addition, infraposition was observed when ankylosis developed in patients aged 20-30 years, with a yearly mean infraposition rate of 0.07 mm/year (range: 0.02-0.21 mm/year) in males and 0.07 mm/year (range: 0.00-0.12 mm/year) in females. The latter findings supported the concept of slow continuous eruption of the teeth. This phenomenon may have implications not only for the treatment of traumatized teeth but also for the treatment of tooth loss by osseointegrated implants, which represent an analogue to the ankylosed replanted tooth.

Adolescent↗
PubMed1999

[Detection of Clostridium difficile toxin A from stool specimens by an enzyme immunoassay kit].

Toxin detection from stool specimens is prerequisite for Clostridium difficile-associated diarrhea and colitis. However, in Japan only one toxin detection kit is commercially available, which requires computerized VIDAS fluorescence reader. In this study we evaluated ImmunoCard Toxin A, which is an enzyme immunoassay with a format of individual cassette and needs no special equipment to perform, by comparing with the VIDAS CDA kit. Of 61 stool specimens 12 were positive and 39 were negative by both assays, 7 were VIDAS positive-ImmunoCard negative, 2 were VIDAS invalid-ImmunoCard negative, and 1 was invalid by both assays. Stool specimens which gave inconsistent results between two assays were subjected to cell culture assay to detect toxin B and culture for C. difficile followed by testing of toxin producibility of isolates. Of 7 VIDAS positive-ImmunoCard negative specimens 5 were negative for cell culture assay and toxigenic C. difficile culture and 2 were positive for cell culture assay. By omitting 3 VIDAS invalid specimens and counting 5 specimens, which were cell culture negative but VIDAS positive, as negative and 2, which were cell culture positive and VIDAS positive, as positive, 12 of the 14 VIDAS positive specimens were ImmunoCard positive (sensitivity, 85.7%) and all 44 VIDAS negative were ImmunoCard negative (specificity, 100%). These results indicate that although in comparison with VIDAS CDA, ImmunoCard Toxin A is slightly less sensitive, ImmunoCard is a rapid, simple, and reliable C. difficile toxin A detection kit, which has the advantage of requiring no special equipment to perform and no centrifuge step, as small as 25 muL of a specimen, and as short as approximately 15 min of time to complete the whole testing.

Bacterial Toxins↗
PubMed1999

Distribution of the cfiA gene among Bacteroides fragilis strains in Japan and relatedness of cfiA to imipenem resistance.

The cfiA gene, encoding an imipenem-hydrolyzing metallo-beta-lactamase produced by Bacteroides fragilis, and insertion-like elements were detected by PCR amplification with B. fragilis strains isolated in Japan. The cfiA gene was found in 1.9 and 4.1% of the imipenem-susceptible B. fragilis isolates collected from 1987 to 1988 and from 1992 to 1994, respectively. Insertion-like elements adjacent to the cfiA gene were found in all nine metallo-beta-lactamase-producing imipenem-resistant strains tested but not in nine cfiA-positive strains with no detectable metallo-beta-lactamase activity.

Bacterial Proteins↗
PubMed1999

Incidence of Prevotella intermedia and Prevotella nigrescens carriage among family members with subclinical periodontal disease.

We established a typing system for Prevotella intermedia and Prevotella nigrescens using the combination of PCR ribotyping and arbitrarily primed PCR (AP-PCR) fingerprinting and applied this system to the study of intrafamilial incidence of these species in the oral cavity. PCR ribotyping followed by subtyping by AP-PCR fingerprinting was applied to each type strain of P. intermedia and P. nigrescens and 54 isolates (32 isolates of P. intermedia and 24 isolates of P. nigrescens) from extraoral infections, resulting in an excellent discriminatory power (discrimination index, 0.99) for both species. A total of 18 subjects from six families, with the subjects from each family comprising the mother, the father, and a child who had subclinical early-stage to moderate adult periodontitis or simple gingivitis and who carried P. intermedia or P. nigrescens, or both, were enrolled in the study of intrafamilial carriage. When 20 colonies per specimen of subgingival plaque, if available, were picked from primary culture, 115 P. intermedia and 178 P. nigrescens isolates were recovered from the 18 subjects. Among the subjects studied, family members shared the same subtype strain(s) but non-family members did not. Multiple subtypes were found in 8 (57%) of the 14 P. nigrescens-positive subjects but in only 3 (27%) of the 11 P. intermedia-positive subjects; the difference was, however, not statistically significant (P = 0.14). These results suggest that the combination of PCR ribotyping and AP-PCR fingerprinting is well suited for the epidemiological study of P. intermedia and P. nigrescens and that each family seems to carry a distinct subtype(s) of these species.

Adolescent↗
PubMed1999

Prevalence of enterotoxigenic Bacteroides fragilis in children with diarrhea in Japan.

In age-matched controlled studies performed in Japan, enterotoxigenic Bacteroides fragilis was isolated from 14.9% of 114 children aged 1 to 14 years with antibiotic-unassociated diarrhea (AUD) and 6.5% of 108 children aged 1 to 6 years with antibiotic-associated diarrhea (AAD). The difference in comparison with control children, was significant for AUD children but not AAD children.

Adenoviruses, Human↗
PubMed1999

Use of PCR and sodium dodecyl sulfate-polyacrylamide gel electrophoresis techniques for differentiation of Prevotella intermedia sensu stricto and Prevotella nigrescens.

Primers were designed from 16S rRNA sequences of Prevotella intermedia sensu stricto and Prevotella nigrescens and were used to discriminate these two species by PCR. The results were compared with those from the PCR technique using primers designed from arbitrarily primed PCR products by Guillot and Mouton (E. Guillot and C. Mouton, J. Clin. Microbiol. 35:1876-1882, 1997). The specificities of both assays were studied by using P. intermedia ATCC 25611, P. nigrescens ATCC 33563, 174 clinical isolates of P. intermedia sensu lato, and 59 reference strains and 58 clinical isolates of other Prevotella species and/or common oral flora. In addition, the usefulness and reliability of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the differentiation of the two species were examined by comparing the results with those from PCR assays. The controversial lipase test for distinguishing these species was also carried out. Unambiguous differentiation was made by both PCR assays, and the results matched each other. The SDS-PAGE assay was found to misidentify a few strains tested, compared with the results of PCR assays. The lipase test was positive for both species, including the reference strains of P. intermedia and P. nigrescens. We conclude that both PCR assays are simple, rapid, reliable, and specific methods which could be used in clinical studies and that the lipase test is not valuable in the differentiation. The reliable discrimination of the two species by SDS-PAGE is questionable.

Bacterial Typing Techniques↗