Biomedical subjects

A Hirai

Publications and source records attributed to A Hirai.

At least 19 recordsLinked to original sources

PubMed2002

Molecular identification of Trichophyton rubrum isolate from a dog by chitin synthase 1 (CHS1) gene analysis.

A nonsporulating isolate from a dog with dermatophytosis was identified as Trichophyton rubrum by molecular analysis. The nucleotide sequence analysis of the chitin synthase 1 (CHS1) gene from the isolate indicated more than 99% sequence similarity with other human and canine isolates of T rubrum. The molecular typing suggested that isolates of T. rubrum from human and canine sources were genetically identical.

Animals↗

PubMed2001

Multiple oral squamous epithelial lesions: are they genetically related?

The development of second primary tumors (SPTs) in patients with head and neck squamous cell carcinoma (HNSCC) has become an increasingly important factor in clinical treatment decisions. Currently, clinical and histologic parameters are used to determine whether or not SPT is present. Recent studies suggest that many SPTs in the upper aerodigestive tract have a common clonal origin, challenging the longstanding multiclonal origin concept. To determine genetic relationships among multiple oral cancerous and precancerous lesions (MOCP), we analysed 100 lesions from 26 Japanese patients. Lesion development was synchronous and metachronous. We looked for patterns of microsatellite alterations (MA) using seven markers at chromosomes 3p14, 9p21, and 17p13, where MA occurs early in oral carcinogenesis. Loss of heterozygosity (LOH) was found in 52.6% (41/78), 62.5% (60/96), and 59.3% (32/54) of informative MOCP at 3p14, 9p21, and 17p13, respectively. Microsatellite instability (MI) was observed in 11, 26 and 13% of the samples at 3p14, 9p21, and 17p13 markers, respectively. Patterns of MA were concordant in only nine (14%) of 63 lesions from four (18%) of 22 patients who initially presented with noninvasive lesions. However, two of four patients with invasive cancer as indexed lesion showed 16 (43%) clonally related MOCP among 37 lesions (P=0.003). The results suggest that the majority of MOCP arise from clonally independent cells affected by field cancerization. However, the probability of mucosal spread of clonal malignant or premalignant cells may increase along with malignant progression.

Carcinoma, Squamous Cell↗

PubMed2001

Interaction of MCC2, a novel homologue of MCC tumor suppressor, with PDZ-domain Protein AIE-75.

AIE-75 is a protein identified as an autoantigen in patients with autoimmune enteropathy and as a colon cancer-related antigen. It has recently been assigned to be a causative gene for Usher type 1C congenital syndromic hearing loss. The novel protein has three PSD-95/Dlg/ZO-1 (PDZ) protein-protein interaction domains and is therefore implicated to function as a molecular anchor or sorter. We have identified a novel protein that binds to AIE-75 by yeast two-hybrid screening. The protein has a high homology to the tumor suppressor MCC (mutated in colon cancer; or MCC1 hereafter) and was named MCC2. MCC2 protein binds the first PDZ domain of AIE-75 with its C-terminal amino acids -DTFL. Since the MCC1 does not bind to AIE-75 and the MCC2 displays different expression patterns in various organs compared to MCC1, they appear to play distinct roles in cells. The MCC2 gene is located on chromosome 19p13 in the vicinity of APCL gene, while MCC1 maps near to APC tumor suppressor gene. Because of negative expression of MCC2 in a panel of cancer cell-lines compared to the corresponding normal tissues, we suggest that further study is necessary to investigate a possible role of MCC2 as a tumor suppressor.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Characterization and expression of the genes for cytochrome c oxidase subunit VIb (COX6b) from rice and Arabidopsis thaliana.

Many of the subunits of cytochrome c oxidase (COX) in the mitochondria of higher plants are encoded by nuclear genes. These genes are less characterized compared to mitochondrial-encoded genes. We previously isolated a cDNA encoding COX6b (designated OsCOX6b1 in this study) from the rice nuclear genome and analyzed its expression. The deduced protein had an extended N-terminus compared with human and yeast COX6b proteins. In this study, we identified another COX6b gene (OsCOX6b2) in rice and revealed that it was actually expressed. The deduced protein of this gene did not have an extended N-terminus and had about the same size as the human and yeast proteins. Genomic Southern hybridization analysis revealed that there was at least one OsCOX6b-homologus sequences in the rice genome other than OsCOX6b1 and OsCOX6b2. Furthermore, we identified three COX6b genes in a dicotyledonous plant, Arabidopsis thaliana. One of these genes (AtCOX6b1) was relatively long, with a length similar to that of OsCOX6b1, and the other two (AtCOX6b2 and AtCOX6b3) were shorter, with lengths similar to the length of OsCOX6b2. Genomic Southern hybridization analysis indicated there were no additional COX6b genes in the Arabidopsis genome. The coding regions of OsCOX6b1 and AtCOX6b1 were separated by four introns and those of OsCOX6b2, AtCOX6b2 and AtCOX6b3 were separated by three introns. A Northern hybridization analysis showed that OsCOX6b1, AtCOX6b1 and AtCOX6b3 were expressed in all organs examined, although with some differences in the amount of expression among the organs. OsCOX6b2 and AtCOX6b2 were strongly expressed in roots but most of the transcripts of AtCOX6b2 were degraded. The evolution of COX6b genes from rice and Arabidopsis is discussed.

Amino Acid Sequence↗

PubMed2001

Numerous and highly developed tubular projections from plastids observed in Tobacco epidermal cells.

Tubular projections from plastids (stromules) were observed using a stroma-targeted green fluorescent protein (GFP) fusion protein and a confocal laser scanning microscope. In tobacco (Nicotiana tabacum) epidermal cells, stromules were observed at a high frequency. Some of them were long and connected plastids. Three days after particle bombardment, 80.6+/-6.99% of the transformed cells contained some plastids with more than one stromule, and 40.2+/-7.7% contained at least one pair of plastids connected by stromules. In a few cells, numerous and highly developed stromules covering the whole cell were observed. Stromules were also observed in epidermal cells in each of three other plant species that were tested: rice, dayflower (Commelina communis) and Arabidopsis thaliana. These findings demonstrated that stromules are common structure in plant epidermal cells.

Journal Article↗

PubMed2001

Maxadilan specifically interacts with PAC1 receptor, which is a dominant form of PACAP/VIP family receptors in cultured rat cortical neurons.

Maxadilan is a potent vasodilator peptide isolated from salivary gland extracts of the hematophagous sand fly. Recently, the possibility was demonstrated that maxadilan binds to PAC1 receptor (PACAP, pituitary adenylate cyclase activating polypeptide type I receptor) in mammals. In the present study, we demonstrated that: (1) maxadilan specifically binds to PAC1 receptor and stimulates cyclic AMP accumulation in a dose-dependent manner in CHO cells stably expressing PAC1 receptor, not VIP (vasoactive intestinal polypeptide) receptors; that (2) the deleted peptide (amino acid #24-42) of maxadilan (termed max.d.4) also specifically binds to PAC1 receptor although max.d.4 inhibits cyclic AMP accumulation stimulated by both maxadilan and PACAP; and that (3) max.d.4 completely blocks the cyclic AMP accumulation induced by VIP in cultured rat cortical neurons. The expression of specific PACAP receptors in cultured rat cortical neurons was further investigated by the reverse transcription-polymerase chain reaction technique, which showed the presence of mRNA coding for PAC1 receptor among PACAP/VIP family receptors. These data indicate that maxadilan and max.d.4 represent important tools for clarifying the physiological role of PAC1 receptor, and that PAC1 receptor plays an important role in the regulation of the functions induced by PACAP in rat cultured cortical neurons.

Amino Acid Sequence↗

PubMed2001

Dominant-negative mutation of p53 tumor suppressor gene in endometrial carcinoma.

BACKGROUND: It has been suggested that mutation of the TP53 tumor suppressor gene is involved in endometrial carcinogenesis. However, the status of p53 function in endometrial cancers has not yet been investigated in detail. METHODS: We surveyed inactivating p53 mutations in endometrial carcinomas using the yeast p53 functional assay, which can evaluate the transcriptional activity of p53 in vivo in yeast. To the detected p53 mutants, we also applied a transdominance assay, which assesses the dominant-negative property of mutants. RESULTS: Of 23 endometrial carcinomas, 9 tumors (39.1%) were found to harbor p53 mutations. Only 1 of the 6 mutants in 18 endometrioid-type tumors showed dominant-negative capacity. In contrast to the endometrioid-type tumor, all 3 mutations in 5 serous-type tumors (R273H, 9-bp deletion in codons 240-243, and R248W) showed dominant-negative capacity and presented in a homozygous state in the tumors, indicating a complete functional inactivation. CONCLUSIONS: Although this study included a relatively small number of cases and therefore is a preliminary study, these results suggest that the dominant-negative mutation of the TP53 gene is related to serous adenocarcinoma. The role of the dominant-negative status of p53 mutants in endometrial carcinogenesis and progression of this disease should be further investigated.

Adult↗

PubMed2001

Murine homologs of deltex define a novel gene family involved in vertebrate Notch signaling and neurogenesis.

Notch signaling plays an important role in cell-fate specification in multicellular organisms by regulating cell-cell communication. The Drosophila deltex gene encodes a modulator of the Notch pathway that has been shown to interact physically with the Ankyrin repeats of Notch. We isolated four distinct cDNAs corresponding to mouse homologs of deltex - mouse Deltex1 (MDTX1), mouse Deltex2 (MDTX2), mouse Deltex2DeltaE (MDTX2DeltaE), and mouse Deltex3 (MDTX3). Deduced amino acid sequences of these four cDNAs showed a high degree of similarity to Drosophila Deltex and its human homolog, DTX1 throughout their lengths, even though they possess distinct structural features. MDTX proteins formed homotypic and heterotypic multimers. We found that these genes were expressed in the central, peripheral nervous system and in the thymus, overlapping with those of mouse Notch1. In mammalian tissue culture cells, overexpression of any of the four mouse deltex homologs suppressed the transcriptional activity of E47, a basic helix-loop-helix (bHLH) protein, in a manner similar to suppression by an activated form of human Notch1 or human DTX1. In addition, overexpression of MDTX2 and MDTX2DeltaE in C2C12 cells under differentiation-inducing conditions suppressed the expression of myogenin, one of the myogenic transcriptional factors; this was also similar to a previously reported activity of constitutively activated Notch. Furthermore, misexpression of any of the MDTX genes in Xenopus embryos resulted in an expansion of the region expressing the neural cell adhesion molecule (N-CAM) gene, a marker for the neuroepithelium. Collectively, our results suggest that these mouse deltex homologs are involved in vertebrate Notch signaling and regulation of neurogenesis.

Amino Acid Sequence↗

PubMed2001

New eudesmane sesquiterpenes from the root of Lindera strychnifolia.

Strychnistenolide (1) and its acetate 2 were isolated from the root of Lindera strychnifolia, along with a novel rearranged type of secoeudesmane, strychnilactone (3). Their structures were elucidated by extensive analysis of their NMR spectra, including 2D NMR techniques, together with an X-ray analysis for 3. Strychnistenolide exists as a single stereoisomer in CHCl(3), but in pyridine is epimerized.

China↗

PubMed2001

A case of POEMS syndrome with high concentrations of interleukin-6 in pericardial fluid.

The POEMS syndrome (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy of various forms, monoclonal gammopathy, skin changes) is a rare multisystem disorder of unknown pathogenesis. Overexpression of proinflammatory cytokines has been implicated in the pathogenesis of POEMS syndrome, however, it is not known whether there is an association between abnormalities in cytokines and pericardial fluid. We present a case of POEMS syndrome with high concentrations of interleukin-6 (IL-6) in pericardial fluid. In our patient, pericarditis developed into cardiac tamponade, and the concentration of IL-6 in pericardial fluid was remarkably elevated compared with that in serum (1760 vs. 6.57 pg mL(-1)). We suggest that IL-6 is associated with the progression or maintenance of pericarditis as a result of POEMS syndrome.

Adult↗

PubMed2001

Development of squamous cell carcinoma from pre-existent oral leukoplakia: with respect to treatment modality.

The present study was undertaken in order to determine whether surgical treatment of oral leukoplakia reduces the risk of the subsequent development of carcinoma. This study included 142 patients with oral leukoplakia who received or did not receive surgical treatment. All subjects were followed-up for more than 6 months with a mean follow-up period of 4 years. Malignant transformation rate was lower among patients who received surgical excision (1/75) than among those who did not receive surgical treatments (4/51). However, the malignant transformation rates were high in patients who received cryosurgery (3/12) or cryosurgery plus surgical excision (1/4). There was no obvious relation between the grade of epithelial dysplasia and the rate of malignant transformation. Our results suggest that surgical excision of oral leukoplakia may reduce the risk of the subsequent development of carcinoma.

Adult↗

PubMed2001

Regulation of FRTL-5 thyroid cell growth by phosphatidylinositol (OH) 3 kinase-dependent Akt-mediated signaling.

Thyrotropin (TSH)-initiated cell cycle progression from G1 to S phase in FRTL-5 thyroid cells requires serum, insulin, or insulin-like growth factor 1 (IGF-1) and involves activation of 3-hydroxy-3-methylglutaryl-CoA reductase, geranylgeranylation of RhoA, p27Kip1 degradation, and activation of cyclin-dependent kinase (cdk) 2. In the present report, we show that the serine-threonine kinase Akt is an important mediator of insulin/IGF-1/serum effects on cell cycle progression in FRTL-5 thyroid cells. The phosphoinositol (OH) 3 kinase inhibitors, Wortmannin (WM) and Ly294002 (LY), block the ability of insulin/IGF-1 to reduce p27 expression, to induce expression of cyclins E, D1, and A as well as cdk 2 and 4, and to phosphorylate retinoblastoma protein. They also inhibit insulin/IGF-1-increased DNA synthesis and cell cycle entrance (S+G2/M). Insulin/IGF-1 rapidly induced activation of Aktl in a PI3 kinase-dependent manner, and increased Aktl RNA levels. Most importantly, FRTL-5 cells transfected with a constitutively active form of Aktl have higher basal rates of DNA synthesis and no longer require exogenous insulin/IGF-1 or serum for TSH-induced growth. In sum, Aktl appears to have an important role in insulin/IGF-1 regulation of FRTL-5 thyroid cell growth and cell cycle progression.

Animals↗

PubMed2001

Inactivate the remaining p53 allele or the alternate p73? Preferential selection of the Arg72 polymorphism in cancers with recessive p53 mutants but not transdominant mutants.

Several reports have noted epidemiological differences in the prevalence or prognostic significance of p53 mutants with arginine (R) or proline (P) at the codon 72 polymorphism (R72/P72) in certain cancer types, but the biological significance of these variants is unclear. The ability of p53 mutants to interact with and inactivate the p53 homolog p73 was recently reported to depend on the conformational state of the p53 protein and the residue at codon 72. Since the conformation of p53 mutants may influence their ability to transdominantly inhibit wild-type p53, we tested whether there was a correlation between the amino acid at codon 72 and the transdominance of p53 alleles found in tumors. The transdominance test was performed using a simple yeast transcription assay, and the amino acid at codon 72 was determined by sequencing. A total of 100 p53 mutants were tested. Compared with the germline frequency (R:P = 427:297), an extreme bias in favor of the R72 allele was observed with recessive mutants (R:P = 50:7, P < 0.0002), whereas no selection for the R72 allele was seen with transdominant mutants (R:P = 23:20). p53 and p73 are known to transactivate overlapping sets of target genes. We interpret the R72 bias with recessive mutants as evidence that decreased activation of p53 target genes provides a selective growth advantage to tumor cells during the stage of tumorigenesis in which a wild-type and mutant p53 allele coexist. We suggest that transdominant p53 mutants achieve this by inactivation of the remaining wild-type p53 allele, whereas recessive p53 mutants achieve it through inactivation of p73.

Alleles↗

PubMed2001

The gene for alternative oxidase-2 (AOX2) from Arabidopsis thaliana consists of five exons unlike other AOX genes and is transcribed at an early stage during germination.

We investigated the expressions of genes for alternative oxidase (AOX1a, AOX1b, AOX1c and AOX2) and genes for cytochrome c oxidase (COX5b and COX6b) during germination of Arabidopsis thaliana, and examined oxygen uptakes of the alternative respiration and the cytochrome respiration in imbibed Arabidopsis seeds. A Northern blot analysis showed that AOX2 mRNA has already accumulated in dry seeds and subsequently decreased, whereas accumulation ofAOX1a mRNA was less abundant from 0 hours to 48 hours after imbibition and then increased. The increase of the capacity of the alternative pathway appeared to be dependent on the expressions of both AOX2 and AOX1a. On the other hand, steady-state mRNA levels of COX5b and COX6b were gradually increased during germination, and the capacity of the cytochrome pathway was correlated with the increase of expressions of the COX genes. Antimycin A, the respiratory inhibitor, strongly increased the expression of AOX1a but had no effect on the expression of AOX2. A 5'RACE analysis showed that AOX2 consists of five exons, which is different from the case of most AOX genes identified so far. Analysis of subcellular localization of AOX2 using green fluorescent protein indicated that the AOX2 protein is imported into the mitochondria.

Amino Acid Sequence↗

PubMed2001

Fulminant Mycoplasma pneumoniae pneumonia.

A 64-year-old woman, who was previously in good health was admitted because of progressive respiratory distress. Her chest radiograph revealed bilateral widespread alveolar infiltrates. She was given a diagnosis of pneumonia caused by Mycoplasma pneumoniae serologically, acute respiratory distress syndrome, and disseminated intravascular coagulation. She died of multiple organ failure despite intensive therapy with mechanical ventilation, intravenous erythromycin and corticosteroids, continuous hemodiafiltration, and plasma exchange. Although Mycoplasma pneumoniae infection is usually a benign self-limited disease, this case emphasizes its potentially serious nature even in normal healthy individuals.

Adrenal Cortex Hormones↗

PubMed2001

Diabetic ketoacidosis associated with recurrent pulmonary edema and rhabdomyolysis in a patient with Turner's syndrome.

Turner's syndrome is a condition involving total or partial absence of one X chromosome and has been associated with a number of diseases including non insulin dependent diabetes mellitus, abnormalities of glucose metabolism and hypothreosis. There have been many case reports in which Turner's syndrome is associated with type 2 diabetes, but the association with type 1 diabetes and/or life threatening complications is very rare. We present an unusual case of a patient with Turner's syndrome who has type 1 diabetes and is complicated with ketoacidosis, severe acute and recurrent pulmonary edema and rhabdomyolysis.

Acidosis↗

PubMed2001

[Troubles inherent to long-term home parenteral nutrition (HPN) and the use of technologies to improve communication between medical institutions and patients].

The continuous advance of technology has contributed to the improvement of the quality of life of patients under long-term home parenteral nutrition (HPN). But the longer the patient stays home, the higher the risk of many kinds of troubles. We designed an HPN system in June 1999, which uses E-mail for patients and to contact with each other (including the patient's family) and to prevent troubles from worsening. We describe the case of a patient which shows the efficacy and usefulness of our system, which makes use of the Internet, video mail, voice mail and electric medical records.

Aged↗

PubMed2000

Stepwise Synthesis of Fullerene Cyclopentadienide R(5)C(60)(-) and Indenide R(3)C(60)(-). An Approach to Fully Unsymmetrically Substituted Derivatives.

Fullerene cyclopentadienide (PhCH(2))(2)Ph(3)C(60)(-) and indenide (PhCH(2))(2)PhC(60)(-), each bearing two different organic groups, were efficiently synthesized through regioselective reactions of 1,4-(PhCH(2))(2)C(60) with an organocopper reagent (PhMgBr/CuBr.SMe(2)) or a Grignard reagent (PhMgBr) followed by deprotonation with KO(t)()Bu.

Journal Article↗