Search PubMed⌕ Search

Biomedical subjects

K Kato

Publications and source records attributed to K Kato.

At least 109 records · Page 6Linked to original sources
PubMed2002

Diagnosis of group A coxsackieviral infection using polymerase chain reaction.

AIMS: To examine the relation between enteroviral infection, especially group A coxsackieviral infection, and acute febrile illness over two summers using tissue culture and polymerase chain reaction (PCR). METHODS: Throat swabs were collected from 246 children from June to August 1997 and 1998. RESULTS: Enteroviruses were isolated from 33/246 samples and 35 other viruses were isolated. Enteroviral genomes were detected in 54/178 samples from which no virus was isolated. Of 41 enteroviral genotypes identified by sequence analysis of PCR products, 38 were group A coxsackieviruses, which are usually difficult to isolate using tissue culture. CONCLUSION: Results indicate that viral detection and identification based on PCR is useful in the diagnosis of group A coxsackieviral infection.

Acute Disease↗
PubMed2002

Age related expression of Werner's syndrome protein in selected tissues and coexpression of transcription factors.

AIMS: Werner's syndrome (WS) is an uncommon autosomal recessive disease resulting from mutational inactivation of human WRN helicase, Werner's syndrome protein (WRNp). Patients with WS progressively develop a variety of aging characteristics after puberty. The aim of this study was to determine the distribution of WRNp and the expression of the transcription factors regulating WRN gene expression in a variety of human organs in an attempt to understand the WS phenotype. METHODS: Tissue specimens were obtained from 16 controls aged from 27 gestational weeks to 70 years of age and a 56 year old female patient with WS. The distribution of WRNp and the expression of the transcription factors regulating WRN gene expression-SP1, AP2, and retinoblastoma protein (Rb)- were studied in the various human organs by immunohistochemical and immunoblot analyses. RESULTS: In the healthy controls after puberty, high expression of WRNp was detected in seminiferous epithelial cells and Leydig cells in the testis, glandular acini in the pancreas, and the zona fasciculata and zona reticularis in the adrenal cortex. In addition, the SP1 and AP2 transcription factors, which regulate WRNp gene expression, appeared in an age dependent manner in those regions where WRNp was expressed. In controls after puberty, SP1 was expressed in the testis and adrenal gland, whereas AP2 was expressed in the pancreas. CONCLUSIONS: These findings suggest that the age specific onset of WS may be related to age dependent expression of WRNp in specific organs.

Adolescent↗
PubMed2002

Mechanism of prostaglandin E2-stimulated heat shock protein 27 induction in osteoblast-like MC3T3-E1 cells.

We investigated the effect of prostaglandin E2 (PGE2) on the induction of heat shock protein 27 (HSP27) and HSP70, and the mechanism behind the induction in osteoblast-like MC3T3-E1 cells. PGE2 time-dependently increased the level of HSP27 without affecting the level of HSP70. PGE2 stimulated the accumulation of HSP27 dose-dependently in the range between 10 nM and 10 microM. PGE2 stimulated the increase in the level of the mRNA for HSP27. Staurosporine and calphostin C, inhibitors of protein kinase C (PKC), suppressed the PGE2-induced HSP27 accumulation. The effect of PGE2 on HSP27 accumulation was reduced in the PKC down-regulated cells. BAPTA/AM, a chelator of intracellular Ca2+, or TMB-8, an inhibitor of intracellular Ca2+ mobilization, reduced the accumulation of HSP27 induced by PGE2. Dibutyryl cAMP had little effect on the basal level of HSP27. PGE2 induced the phosphorylation of both p44/p42 mitogen-activated protein (MAP) kinase and p38 MAP kinase. PD98059 and U-0126, inhibitors of the upstream kinase of p44/p42 MAP kinase, reduced the accumulation of HSP27 induced by PGE2. SB203580, a specific inhibitor of p38 MAP kinase, suppressed the HSP27 accumulation induced by PGE2. U-73122, an inhibitor of phospholipase C, and calphostin C reduced the PGE2-induced phosphorylation of both p44/p42 MAP kinase and p38 MAP kinase. These results indicate that PGE2 stimulates the induction of HSP27 through PKC-dependent activations of both p44/p42 MAP kinase and p38 MAP kinase in osteoblasts.

Analysis of Variance↗
PubMed2002

Human chorionic gonadotropin exhibits normal biological activity in patients with recurrent pregnancy loss.

To test the hypothesis that the structural abnormality of human chorionic gonadotropin (hCG) may induce recurrent pregnancy loss, we examined the biological activity of hCG in pregnant women with a history of repeated miscarriages (n = 44). Pregnant women without a history of miscarriage (n = 85) were included as controls. Serum hCG, estradiol (E2) and progesterone levels were found to be significantly lower in the pregnancy loss group. There was no difference in serum thyroid hormone levels. Sera from both groups of women were then incubated with Chinese hamster ovary (CHO) cells transfected with hCG/luteinizing hormone receptor (CHO-hCG/LHr) or human thyroid stimulating hormone receptor (CHO-hTSHr). Biological response to hCG in women with recurrent pregnancy loss was identical to that of women in the control group in both CHO-hCG/LHr and CHO-hTSHr cells. When sera were subjected to high performance liquid chromatography, no difference in hydrophobicity was observed between control and patients groups. The structure of the hCG molecule and its biological activity in women with a history of recurrent pregnancy loss are apparently not different from those in women with normal pregnancy. Lower serum progesterone and E2 levels in the patient group can be explained by lower serum hCG levels in these women. Intrinsic gonadotropic and thyrotropic activities of the hCG molecule appear to play no major role in recurrent pregnancy loss.

Abortion, Habitual↗
PubMed2001

The loss of susceptibility to apoptosis in exudated tissue neutrophils is associated with their nuclear factor-kappa B activation.

Tissue neutrophils, human salivary neutrophils donated from healthy subjects and synovial fluid neutrophils collected from patients with rheumatoid arthritis were compared with circulating blood neutrophils. Concomitant treatment of circulating blood neutrophils with tumor necrosis factor-alpha (TNF-alpha) and cycloheximide induced neutrophil apoptosis, whereas the same treatment failed to induce significant apoptosis in salivary and synovial fluid neutrophils. Caspase-3 activation by TNF-alpha was observed in these tissue neutrophils, although its activity was significantly weaker than that in circulating blood neutrophils. In circulating blood neutrophils, TNF-alpha induced activation of nuclear factor-kappa B (NF-kappa B), whereas, in tissue neutrophils, NF-kappa B had been already activated without any stimulation, and no further activation was induced by the treatment with TNF-alpha. Furthermore, while pretreatment of neutrophils with an NF-kappa B inhibitor produced typical apoptotic changes in circulating blood neutrophils, this inhibitor did not produce any morphological apoptotic changes induced by TNF-alpha in tissue neutrophils. These results indicate that neutrophils undergo marked functional changes such as altered sensitivity to apoptosis-inducing stimuli in association with their exudation from blood into tissue, and that NF-kappa B activation is involved in the acquisition of resistance to TNF-alpha-induced apoptosis.

Apoptosis↗
PubMed2001

Inhibitory effect of M50054, a novel inhibitor of apoptosis, on anti-Fas-antibody-induced hepatitis and chemotherapy-induced alopecia.

M50054, 2,2'-methylenebis (1,3-cyclohexanedione), was identified as a novel inhibitor of apoptosis (programmed cell death) using an in vitro cell death assay system induced in human Fas-expressing WC8 cells by soluble human Fas ligand. Furthermore, M50054 inhibited the apoptotic cell death of U937, a human monocytic leukemic cell line, induced by anticancer agents such as etoposide; it was also confirmed that M50054 inhibited apoptotic features such as DNA fragmentation and phosphatidylserine exposure in these cells. These anti-apoptotic effects were attributable to inhibition of caspase-3 activation. Additionally, M50054 significantly inhibited anti-Fas-antibody-induced elevation of plasma alanine aminotransferase and aspartate aminotransferase. Alopecia (hair loss) symptoms were also significantly improved with topical treatment with M50054. In conclusion, M50054 inhibits apoptosis induced by a variety of stimuli via inhibition of caspase-3 activation, and may thus be effective for hepatitis and chemotherapy-induced alopecia.

Alopecia↗
PubMed2001

Noradrenaline stimulates 5-hydroxytryptamine release from mouse ileal tissues via alpha(2)-adrenoceptors.

The effect of noradrenaline on 5-hydroxytryptamine (5-HT) release from isolated mouse ileal tissues was investigated. Noradrenaline, but not isoprenaline, at 1 microM stimulated 5-HT release, an effect which was inhibited by yohimbine, an alpha(2)-adrenoceptor antagonist, but not by bunazosin, an alpha(1)-adrenoceptor antagonist. alpha(2)-Adrenoceptor agonists, UK 14,304 (5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline) and clonidine at a higher concentration (10 microM) also stimulated 5-HT release, while alpha(1)-adrenoceptor agonists, methoxamine and phenylephrine, had no effect. The effect of noradrenaline was completely abolished in ileal tissues isolated from mouse treated with pertussis toxin (100 microg/kg, i.v.) for 2 days. These results suggest that noradrenaline causes 5-HT release from enterochromaffin cells in mouse ileal tissues via alpha(2)-adrenoceptor subtypes coupled to a pertussis toxin-sensitive G protein.

Adrenergic alpha-2 Receptor Agonists↗
PubMed2001

Frequent beta-catenin mutation and cytoplasmic/nuclear accumulation in pancreatic solid-pseudopapillary neoplasm.

Significance of Wnt signaling with beta-catenin mutations on solid-pseudopapillary neoplasm (SPN) of the pancreas was studied by immunohistochemistry and molecular analysis. On immunohistochemistry, all 18 SPNs tested showed diffuse cytoplasmic/nuclear positivity for beta-catenin. Upon direct DNA sequencing of exon 3 of the beta-catenin gene, 15 (83%) of the 18 SPNs showed 1-bp missense mutation in codons 32 (5 cases), 33 (3 cases), 34 (3 cases), 37 (3 cases), and 41 (1 case). Immunoreactivity for cyclin D1, one of the intranuclear targets of beta-catenin complexes, was found in tumor cells of more than half the tumor cells of all of the 18 SPNs. The present study strongly suggested a significant role of Wnt signaling, mostly associated with beta-catenin mutations in the tumorigenesis of SPN.

Adolescent↗
PubMed2001

Expression of a novel member of the ATP1G1/PLM/MAT8 family, phospholemman-like protein (PLP) gene, in the developmental process of mouse cerebellum.

We have identified a new member of the ATP1G1/PLM/MAT8 family, named phospholemman-like protein (PLP), from a mouse cerebellum cDNA library. The family consists of small transmembrane proteins that modulate the activities of some ion channels. The deduced amino acid sequence of PLP consists of 93 residues that contain the ATP1G1/PLM/MAT8 motif and a single transmembrane domain, and is most similar to the sequence of mouse phospholemman. In situ hybridization analysis showed that the PLP gene is highly expressed in cerebellar granule cells. PLP expression is elevated in the postnatal developing cerebellum. Thus, it may be implicated in the proliferation, differentiation, and axon elongation of granule cells as they mature and migrate to the internal granule layer.

Amino Acid Sequence↗
PubMed2001

Altered calcium dynamics in cultured cerebellar cells from IP3R1-deficient mice.

Intracellular calcium release in response to bath-applied quisqualate or caffeine was examined in cerebellar primary cultures of type-1-inositol-1,4,5-trisphosphate-receptor (IP3R1)- deficient mice. Under [Ca2+]o-free conditions, calcium release in response to 10 microM quisqualate was significantly reduced in Purkinje cells, but was unaffected in granule cells, suggesting that different subtypes of IP3 receptors contribute to the metabotropic glutamate response in these cells. In addition, calcium release in response to 10 mM caffeine under [Ca2+]o-free conditions was not impaired in cerebellar cells, suggesting that IICR and CICR are independently regulated in cerebellar cells. Moreover, in both wild-type and homozygous mutant mice, CICR in granule cells was approximately 6 times greater than in Purkinje cells.

Animals↗
PubMed2001

Sodium butyrate induces growth arrest and senescence-like phenotypes in gynecologic cancer cells.

We demonstrated here the growth-suppressing effects of sodium butyrate (NaB) on human endometrial and ovarian cancer cells. The arrest of cells at the G1 checkpoint accounted for this effect. NaB-mediated p21 might arrest endometrial and ovarian cancer cells at the G0/G1 phase by eliciting pRb unphosphorylation. To demonstrate the role of pRb regulation by p21, we measured the sensitivity to NaB of cervical cancer cells in which pRb had been inactivated by HPV E7. The cervical cancer cells displayed a sensitivity in NaB-mediated G2/M arrest in addition to their sensitivity in G0/G1 arrest. Arrest at G0/G1 and G2/M accompanied induction of senescence-like phenotypes (SLPs). Most importantly, the effect of NaB on senescence induction was not coupled with the predominance of hypophosphorylated pRb forms in the cervical cancer cells. This suggested that NaB had the potential to elicit SLPs through p21-mediated withdrawal from cell cycle progression. The consequences of p21 induction were manifold. The effects of NaB on gynecologic cancer cell growth indicated its potential use in cancer treatment. NaB was effective even in the cancer cells with mutant p53 and/or Rb genes by eliciting cell senescence.

Animals↗
PubMed2001

Development of sensitive high-performance liquid chromatography with fluorescence detection using 4-(4,5-diphenyl-1H-imidazol-2-yl)-benzoyl chloride as a labeling reagent for determination of bisphenol A in plasma samples.

A sensitive HPLC method for determination of bisphenol A (BPA) in plasma samples using 4-(4,5-diphenyl-1H-imidazol2-yl)benzoyl chloride (DIB-Cl) as a fluorescence labeling reagent was developed. The fluorescence labeling reaction was completed within 10 min at room temperature. DIB-Cl reacts with the phenolic hydroxyl group of BPA in the presence of triethylamine (TEA). The DIB-Cl derivative of BPA (DIB-BPA) was separated within 30 min with an ODS column using acetonitrile-water (90:10, v/v) as the isocratic eluent. Calibration graphs were linear over the range of 1.0-100 ng/ml (r=0.999). The detection limit of DIB-BPA was 0.05 ng/ml (2.5 pg) at a signal-to-noise ratio of 3. The relative standard deviations (RSDs) of the method for between-run were 1.0-5.0%. The analytical recoveries of known amounts (1.0 and 100 ng/ml) of BPA-spiked rabbit plasma were around 95%.

Animals↗
PubMed2001

Nonsense and frameshift mutations in ZFHX1B, encoding Smad-interacting protein 1, cause a complex developmental disorder with a great variety of clinical features.

Mutations in ZFHX1B, encoding Smad-interacting protein 1 (SIP1), have been recently reported to cause a form of Hirschsprung disease (HSCR). Patients with ZFHX1B deficiency typically show mental retardation, delayed motor development, epilepsy, microcephaly, distinct facial features, and/or congenital heart disease, in addition to the cardinal form of HSCR. To investigate the breadth of clinical variation, we studied DNA samples from six patients with clinical profiles quite similar to those described elsewhere for ZFHX1B deficiency, except that they did not have HSCR. The results showed the previously reported R695X mutation to be present in three cases, with three novel mutations-a 2-bp insertion (760insCA resulting in 254fs262X), a single-base deletion (270delG resulting in 91fs107X), and a 2-bp deletion (2178delTT resulting in 727fs754X)-newly identified in the other three. All mutations occurred in one allele and were de novo events. These results demonstrate that ZFHX1B deficiency is an autosomal dominant complex developmental disorder and that individuals with functional null mutations present with mental retardation, delayed motor development, epilepsy, and a wide spectrum of clinically heterogeneous features suggestive of neurocristopathies at the cephalic, cardiac, and vagal levels.

Abnormalities, Multiple↗
PubMed2001

Distinct orders of GalNAc incorporation into a peptide with consecutive threonines.

Mucin O-glycosylation is initiated by a transfer of N-acetyl-d-galactosamine (GalNAc) to Ser and Thr residues in polypeptides with a family of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (pp-GalNAc-Ts). In this paper, four human pp-GalNAc-Ts (pp-GalNAc-T1, T2, T3, and T4) were tested for their preferential orders of GalNAc incorporation into FITC-PTTTPITTTTK, a portion of the tandem repeat of human MUC2. The products were separated by reverse-phase HPLC and characterized by MALDI-TOF MS and peptide sequencing. pp-GalNAc-T1 showed preference for acceptor sites, but the order of the incorporation into these sites seemed to be random. In contrast, the GalNAc incorporation by pp-GalNAc-T2, T3, or T4 was not only site-specific but also according to the specific orders. Furthermore, pp-GalNAc-T2, T3, or T4 had distinct maximum numbers of GalNAc incorporations into this peptide.

Acetylgalactosamine↗
PubMed2001

Enantiomeric purity determination of malic acid in apple juices by multi-beam circular dichroism detection.

A multi-beam circular dichroism (CD) detector which is easily constructed by inserting inexpensive optics into a conventional photo-diode array detector has an advantage of simultaneous detection of the absorbance and CD. The enantiomeric purity determination of malic acid in beverages was performed by this detection system. Malic acid when complexed with Cu(II) was found to have an absorbance maximum at around 750 nm. The L-malic acid-Cu(II) complex showed a positive Cotton effect in its absorbance band and its anisotropy factor (delta epsilon/epsilon) was relatively large at about 1/170. This complex was retained on a reversed-phase column with the addition of racemic 2-hydroxy-3-methylbutyric acid to the mobile phase as the ligand. A plot of the relative peak areas between the CD and the absorption (delta abs/abs) versus optical purity showed good linearity with a correlation coefficient of 0.999, and the precision expressed as the relative standard deviation of the errors from the regression line was +/-2.7% (2sigma). The accuracy of the proposed method was assessed by capillary electrophoresis. Eight commercially available juice products were analyzed using this method. Five of them were thought to be adulterated with synthetic malic acid.

Beverages↗