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Biomedical subjects

M Yamauchi

Publications and source records attributed to M Yamauchi.

At least 181 records · Page 10Linked to original sources
PubMed1996

Identification and characterization of a new gene physically linked to the ATM gene.

Ataxia telangiectasia (AT) is an autosomal recessive disease of unknown etiology associated with cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, and hypersensitivity to ionizing radiation. Although AT has been divided into four complementation groups by its radioresistant-DNA synthesis phenotype, the ATM gene has been isolated as the candidate gene responsible for all AT groups. We identified a new gene, designated NPAT, from the major AT locus on human chromosome 11q22-q23. The gene encoded a 1421-amino-acid protein containing nuclear localization signals and phosphorylation target sites by cyclin-dependent protein kinases associated with E2F. The messenger RNA of NPAT was detected in all human tissues examined, and its genomic sequence was strongly conserved through eukaryotes, suggesting that the NPAT gene may be essential for cell maintenance and may be a member of the housekeeping genes. Analysis of the genomic region of NPAT surprisingly revealed that the gene existed only 0.5 kb apart from the 5' end of the ATM transcript with opposite transcriptional direction. It may be possible to propose the idea that the promoter region could be shared by both housekeeping genes and that each gene could influence the expression of the other.

Amino Acid Sequence↗
PubMed1996

Association of restriction fragment-length polymorphisms in the alcohol dehydrogenase 2 gene with alcoholic brain atrophy.

Alcohol abuse can induce brain atrophy, but it only occurs in some alcoholics. To investigate whether genetic polymorphism of alcohol-metabolizing enzymes [including alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH)] was related to alcoholic brain atrophy, we determined restriction fragment-length polymorphisms of the ADH2 and ALDH2 genes in 77 male alcoholics. Computed tomography was used to determine the severity of brain atrophy. Digestion with MaeIII and MboII after polymerase chain reaction amplification showed that the ADH2(1) gene frequency was significantly higher in patients with brain atrophy than in those without brain atrophy (chi 2 = 9.274, p < 0.01), whereas no significant association was observed between brain atrophy and the ALDH2 gene Multivariate analysis (including age, total alcohol intake, liver cirrhosis, and ADH2 genotype) showed that the ADH2(1)/ADH2(1) genotype was associated with alcoholic brain atrophy. These findings suggest that the ADH2(1) allele may be associated with alcoholic brain atrophy.

Adult↗
PubMed1996

Effects of cimetidine on blood ethanol levels after alcohol ingestion and genetic polymorphisms of sigma-alcohol dehydrogenase in Japanese.

Administration of cimetidine, an H2-receptor antagonist increases blood alcohol concentrations. This has been attributed to decreased gastric first-pass metabolism of ethanol caused by cimetidine's inhibitory effect on gastric alcohol dehydrogenase (sigma-ADH) activity. Molecular studies on sigma-ADH showed that a point mutation might occur at position 287 (G --> T) of the sigma-ADH gene in Japanese deficient type of sigma-ADH activity. To clarify the relationship between first-pass metabolism of ethanol and polymorphism of sigma-ADH, we analyzed the nucleotide sequence at positions 287 and 294 of sigma-ADH in 11 individuals who were administered ethanol orally before and after treatment with cimetidine. Higher blood ethanol levels after cimetidine administration were found in 4 of 11 cases (group A), whereas high blood ethanol levels were observed in 7 of 11 cases (B group), irrespective of cimetidine administration. Genetic polymorphisms at position 287 and 294 were not observed in all subjects. Even in 59 Japanese men with various alcoholic liver diseases, no polymorphisms at position 287 were observed by restriction-length polymorphisms with Avail digestion after polymerase chain reaction.

Adult↗
PubMed1996

Local production of corticotropin releasing hormone is increased in experimental intestinal inflammation in rats.

BACKGROUND/AIMS: Corticotropin releasing hormone (CRH) suppresses immunological functions via stimulation of the pituitary-adrenal axis, but is also found in peripheral tissues. Peripheral proinflammatory activity of CRH is suggested by increased tissue concentrations in arthritis and in vitro immunostimulatory effects. This study evaluated intestinal CRH concentrations, immunolocalisation, and synthesis in chronic enterocolitis and investigated in vitro responsiveness of lamina propria mononuclear cells to CRH. METHODS: Chronic granulomatous enterocolitis was induced by intramural injection of peptidoglycan-polysaccharide polymers in the ileocaecal region of Lewis rats. CRH protein was measured in caecal specimens by immunohistochemistry and radioimmunoassay and caecal CRH mRNA expression was analysed by reverse transcriptase polymerase chain reaction. RESULTS: In the chronically inflamed caecum abundant immunoreactive CRH was found in inflammatory cells, mesenchymal cells, as well as in myenteric plexi. In contrast, only a few CRH containing cells were detected in normal and HSA injected control caecums. Moreover, caecal CRH protein levels were increased during chronic enterocolitis. Local CRH synthesis as indicated by mRNA expression was considerably increased in chronic enterocolitis whereas it was undetectable or low in uninflamed caecum. In addition, CRH stimulated in vitro proliferation of lamina propria mononuclear cells and inhibited mitogen induced proliferation. CONCLUSION: Increased CRH protein and mRNA expression in chronic enterocolitis and responsiveness of intestinal mononuclear cells to CRH indicate an immunomodulatory role for locally produced CRH in intestinal inflammation.

Animals↗
PubMed1996

Quantification of serum hepatitis C virus core protein level in patients chronically infected with different hepatitis C virus genotypes.

BACKGROUND/AIM: A novel fluorescent enzyme immunoassay (FEIA) for the detection and quantification of serum hepatitis C virus (HCV) core protein was developed. The aim of this study was to evaluate the relation among serum HCV core protein level, HCV RNA level, and HCV genotype in patients with chronic HCV infection. PATIENTS AND METHODS: Serum HCV core protein, HCV RNA, HCV genotype were determined in 175 patients using the FEIA, branched DNA assay (Quantiplex HCV RNA ver 1.0), and serologically defined genotyping assay, respectively. For the specificity, all 13 patients seronegative for anti-HCV were negative for serum core antigen and HCV RNA by FEIA and bDNA, respectively. RESULTS: FEIA assay seems to be more sensitive than bDNA for patients with HCV type 2 infection (detection: 83.4% v 63.4%, p < 0.01). There was a good overall correlation between the FEIA and bDNA results. However, when the patients were stratified into their HCV types, a correlation was observed in HCV type 1 but not in type 2 infection. Patients with HCV type 2 infection had a lower serum HCV core protein level (median 56 RFI) compared with type 1 infection (median 149 RFI, p < 0.01). Thirty seven patients subsequently received interferon alpha therapy, patients who showed a complete and sustained response had a lower pretreatment serum HCV core protein level compared with patients who had a relapse and nonresponders (36 v 338 RFI, p < 0.01). CONCLUSIONS: This study showed that FEIA (1) is a good assay for the detection and quantification of serum HCV core protein level, (2) is also very sensitive in detecting HCV core protein in patients with HCV type 2 infection, and (3) may have a role as a predictor of subsequent response to interferon therapy.

Female↗
PubMed1996

Protein characterization of fluorosed human enamel.

Despite extensive investigation, the development mechanism or mechanisms resulting in dental fluorosis are unknown. Several hypotheses suggest abnormal matrix synthesis, secretion, and delayed and/or defective matrix degradation with retention of enamel protein. The purpose of this study was to characterize the protein composition of fluorosed human enamel. Nine permanent moderately fluorosed (developed in a 3.2 ppm H2O area) and ten permanent normal control teeth (from individuals with < 0.2 ppm F in their drinking water) were evaluated. The enamel fluoride concentration, protein content, and amino acid composition were determined for each tooth. The enamel proteins were further characterized by gel electrophoresis and by Western blot analysis by means of polyclonal antibodies raised against recombinant amelogenin protein. Fluorotic enamel had significantly elevated (p = 0.0001) F levels compared with normal enamel (mean [F-] fluorosed = 431 ppm; mean [F-] control = 62 ppm). While there was a significantly greater protein content by weight in fluorosed enamel compared with normal enamel (mean fluorosed = 0.27%; mean control = 0.11%), the amino acid profiles were similar for fluorosed and normal enamel. Gel electrophoresis showed fluorosed enamel to have a greater diversity of primarily low-molecular-weight proteins compared with normal enamel. Western blot analysis did not indicate retention of amelogenin in either fluorosed or normal enamel. This investigation showed that the protein content of fluorosed enamel was greater than that of normal enamel; however, the amino acid compositions were similar for fluorosed and normal enamel. Furthermore, there does not appear to be retention of significant amounts of amelogenin in fully mature, moderately fluorosed human enamel. Although delayed removal of the enamel matrix proteins may play a role in the hypomineralization defects seen in fluorosed enamel, the majority of these proteins are absent in the mature tissue of these moderately fluorosed teeth.

Amelogenesis↗
PubMed1996

Differential distribution of lumican and fibromodulin in tooth cementum.

The objectives of this study were to isolate and characterize the major proteoglycans of tooth cementum in relation to the tissue's mineralization. Cementum was collected from the root apex region of bovine molars and pulverized. It was first extracted with 6M guanidine-HCI, pH 7.4 (G-extract, mineral-unassociated) and then demineralized and extracted with 0.5M EDTA (E-extract, mineral-associated). Both extracts were applied to anion exchange and then molecular sieve chromatography to isolate proteoglycans. The fractions collected were assayed for chondroitin-(CS) and keratan sulfate (KS) containing proteoglycans using the monoclonal antibodies 2-B-6 and 5-D-4, respectively. It was found that the KS was the major glycosaminoglycan and was enriched in the G-extract fraction. The major KS fraction was then applied to 7.5% SDS-PAGE. The major broad band (69 kDa) was 5-D-4 positive in Western blot analysis and separated into two bands (46 kDa and 50 kDa) after treatment with keratanase II and endo-beta-galactosidase. These two proteins were transfered to PVDF membrane and analyzed for amino acid sequence. The results showed the major band (46 kDa) to be lumican and the minor (50 kDa) fibromodulin. In addition, based on the immunohistochemical study using a number of mono- and polyclonal antibodies including 5-D-4, anti-lumican core protein as well as anti-fibromodulin core protein antibodies, the KSPGs were found to be located almost exclusively in nonmineralized portions of cementum such as precementum and the pericementocyte area. These biochemical as well as immunohistochemical data suggest that the major KSPGs of cementum, lumican and fibromodulin, have a specific tissue distribution and may have regulatory roles in cementum mineralization.

Amino Acid Sequence↗
PubMed1996

Characterization of the bone sialoprotein (BSP) gene promoter.

Bone sialoprotein is a 34 kDa phosphorylated and sulphated glycoprotein that is essentially unique to mineralizing connective tissues. Recent studies on the developmental expression of BSP mRNA and the temporo-spatial appearance of the protein during bone formation in vivo and in vitro have demonstrated that BSP is expressed by differentiated osteoblasts and that it may function in the initial nucleation of hydroxyapatite crystals in de novo bone formation. To study the cell-specific regulation of BSP we have isolated genomic clones that encompass the BSP promoter regions of both the human and rat genes. These promoters are characterized by a highly conserved region (BSP Box) that extends upstream from the transcription start site to nt -370. Within this region the immediate promoter is further characterized by a unique inverted TATA box and an inverted CCAAT box, both of which are required for basal transcriptional activity. The TATA box is overlapped by a vitamin D3 response element (VDRE) which appears to mediate vitamin D suppression of BSP gene transcription by competing with the TATA-binding protein (TBP) for occupancy of the site of the pre-initiation complex formation. Mutation of the inverted TATA box into a normal TATA sequence increases transcription slightly but does not affect the functionality of the VDRE indicating that the orientation of the TATA box is not critical for these functions. Further upstream an AP-1 site, overlapped by a steroid hormone response-like sequence, mediates down-regulation of BSP transcription induced by TPA that is abrogated by a complex interaction between Jun and the glucocorticoid receptor protein induced by dexamethasone. Thus, the characterization of approximately 3 kb of the BSP promoter and approximately 2 kb of the first intron has revealed several sites of transcriptional regulation that are important in regulating BSP expression and, consequently, bone formation.

Animals↗
PubMed1996

Developmental changes in skin collagen biosynthesis pathway in posthatch male and female chickens.

The developmental changes in skin collagen biosynthesis pathway in male and female chickens were evaluated. Concentration of collagen, levels of mRNA for collagen type I subunits and for lysyl hydroxylase, and the level of three lysyl oxidase-derived cross-links: dehydro-dihydroxylysinonorleucine (DHLNL), dehydro-hydroxylysinonorleucine (HLNL), and dehydro-histidinohydroxymerodesmosine (HHMD) were determined during 4 wk posthatching. Skin collagen content increased with age and was higher in males than in females. In both sexes, the expression of the genes coding for alpha 1 and alpha 2 of collagen type I decreased with age: alpha 1(I) gene expression decreased from Day 3 onwards, whereas the reduction in alpha 2(I) gene expression started 1 wk later. At all ages examined, the expression of both genes was higher in male than in female skin. Males and females lysyl hydroxylase gene expression remained low until Day 16, after which an increase in the enzyme gene expression was observed. An increase in skin HLNL content was observed from Day 3 in both sexes reaching a peak in males at Day 9 and in females 1 wk later. The DHLNL content, which was higher in males than in females at all ages tested, dramatically decreased in both male and female skin from 3 d of age, reaching its lowest level at Day 16, and remained at that low level thereafter. The skin content of HHMD in males and females followed an oscillatory behavior with higher peaks in the male skin. The results suggest that the higher tensile strength of male skin than female skin may be due to the elevated skin collagen content that resulted from increased expression in collagen type I genes on the one hand, and from the higher amounts of various collagen cross-links on the other.

Aging↗
PubMed1996

[Cochlear ischemia and changes in compound action potentials in the guinea pig].

To determine the degree of decrease in cochlear blood flow (CoBF) which causes compound action potentials (CAPs) to disappear, a cochlear ischemic model was created by compressing the internal auditory artery in guinea pig. CoBF was measured with a laser Doppler flowmeter, and CAPs were recorded with an electrode placed on the round window membrane. The amplitude and latency of the N1 wave of CAPs changed as CoBF decreased. When CoBF diminished to as much as 70% below the original level, N1 disappeared. In this study, we also observed the N1 recovery process following CoBF reperfusion after 20 minutes of cochlear ischemia. N1 recovery in the group with an incomplete decrease in CoBF was better than in the group with a complete decrease in CoBF. These findings suggest that both the degree of compromise of CoBF and the duration of ischemia are important factors affecting the recovery of auditory function.

Animals↗
PubMed1996

[The changes in cochlear blood flow and auditory brainstem response in the pressure-induced animal model of acoustic neuroma].

Changes in cochlear blood flow (CoBF) and auditory brainstem response (ABR) in a pressure-induced animal model of acoustic neuroma were examined. A suboccipital approach was used to expose the right cerebello-pontine angle in guinea pigs. Under surgical microscope, the bundle of nerves and vessels at the entrance of the internal auditory meatus was exposed without retraction. The two pressure points, one anterior to and the other posterior to the center of the bundle were separately compressed by a pressure probe (1mm in diameter). CoBF from the basal turn or second turn of the right cochlea was measured with a laser Doppler flowmeter. ABR was recorded from the electrodes placed on the vertex and the right mastoid process. With compression, the changes in CoBF and ABR were found in a total of 19 animals. We classified these changes into three types based mainly on CoBF. In type I (n = 9), an increase rather than a decrease of CoBF was noted, and an increase in the I-II inter-peak latency with a decrease in the amplitudes of wave II-IV in ABR were observed. Those changes were mainly attributed to the blockage of cochlear nerve. In type II (n = 6), CoBF was completely stopped and all waves of ABR disappeared during compression. This suggested the presence of cochlear ischemia. After relaxation of compression both CoBF and ABR recovered, but I-II inter-peak latency remained delayed. CoBF in type III (n = 4) decreased and then slowly recovered. In type III, all waves transiently disappeared, and wave I reappeared with recovery of CoBF. The changes in type III were caused by damage to both the artery and the nerve. In addition, the changes in CoBF and ABR were closely related to the pressure points. The changes in type I were often found in compression of the anterior pressure point, whereas the changes in type II are associated with the posterior pressuring point (p < 0.05). The results indicate that the cochlear nerve or the internal auditory artery is more susceptible to damage by compression of an anterior or posterior pressure point, and that the compression position is an important determinant in the type of auditory dysfunction and the degree of hearing loss.

Animals↗
PubMed1996

[A case of hepatocellular carcinoma responding to oral administration of 5'-DFUR].

A 65-year-old female patient with liver cirrhosis complicated with hepatocellular carcinoma (HCC) was treated with oral administration of 5'-DFUR (600 mg/day). The titer of serum alpha-fetoprotein gradually decreased, and reduction of the hepatic tumor size was observed by abdominal computed tomography (CT) following 5'-DFUR treatment. HCC was obviously diminished since the start of 5'-DFUR administration and almost disappeared in fifteen months. This case suggests the treatment with 5'-DFUR for hepatocellular carcinoma is completely effective.

Administration, Oral↗
PubMed1996

[Two operated cases of synchronous double cancer of the lung and digestive tract in patients over 80 years old and genetical diagnosis].

Synchronous double cancer of the lung and gastrointestinal organ was successfully resected by an one-step approach in two aged patients over 80 years. An 81-year-old man was clinically diagnosed as having a right lung cancer (S3) along with a sigmoid colon cancer. The pathological cell types of these cancers were squamous cell carcinoma and adenocarcinoma respectively. Right upper lobectomy and sigmoidectomy were performed at the same time because he had no risks for the operation. An-80-year-old woman was diagnosed as having a left lung cancer (S8-9) along with a stomach cancer. The cell types of these cancers were both highly differentiated adenocarcinoma. Left lower lobectomy and subtotal gastrectomy were performed at the same time, too. We limited lymph nodes dissection to shorten the operation time and no postoperative complications occurred in both patients. It is suggested that simultaneous operation for double cancer in aged patients can be safely performed in selected cases. In the latter patient, pathological cell type of the lung cancer was similar to that of stomach cancer. So we applied polymerase chain reaction (PCR) for making a diagnosis of double cancer postoperatively, and it was proved that the lung and gastric cancers were different from each other in genetical natures. Application of the genetical technique to clinical field which greatly contribute to making a diagnosis of double cancer is expected.

Adenocarcinoma↗
PubMed1996

Valve replacement with the CarboMedics bileaflet mechanical prosthesis: clinical results at midterm.

OBJECTIVE: We study the clinical midterm results of the valve replacement with the CarboMedics bileaflet mechanical prosthesis. EXPERIMENTAL DESIGN AND SETTING: Retrospective study. Institutional practice (National Cardiovascular Center, Osaka, Japan). PATIENTS AND INTERVENTIONS: 167 CarboMedics prostheses were implanted in 144 patients from April, 1990 and December, 1993. Of these, 77 patients underwent isolated aortic valve replacement (AVR), 45 patients underwent isolated mitral valve replacement (MVR), 21 patients underwent double (aortic and mitral) valve replacement (DVR), and one patient underwent triple (aortic, mitral and tricuspid) valve replacement (TVR). MEASURES: Events were defined in accordance with the guidelines for reporting morbidity and mortality after cardiac valve operations of the Society of Thoracic Surgeons/American Association for Thoracic Surgery.

Aortic Valve↗
PubMed1996

[Constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II)].

We experienced a case of constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II). The patient complained of orthopnea and leg edema. The cause of constrictive pericarditis was pericardial effusion due to dissecting aortic aneurysm. Ascending aortic replacement with graft and decortication of thickened pericardium were performed. We confirmed the decrease of CVP and PAP intraoperatively. Postoperative course was uneventful.

Aged↗