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Biomedical subjects

T Horiuchi

Publications and source records attributed to T Horiuchi.

At least 91 records · Page 5Linked to original sources
PubMed2000

Functional genomics of Escherichia coli in Japan.

Completion of the genome sequence of the model bacterium Escherichia coli has produced nearly 2000 open reading frames (ORFs) that remain to be functionally characterized. To accomplish this goal, we have organized a working project team in Japan and have begun construction of clones containing each of the putative ORFs. The procedure has been conceived such that we shall be able to perform systematic analysis of the shut-off as well as forced expression in vivo of each ORF and purification of its protein product for further biochemical studies. In addition, we have started a collection of various genetic and biochemical data of E. coli published in the past, and analyses of the data from a bio-informatics point of view. Thus, we aim at reaching complete understanding of this model organism in the near future.

Bacterial Proteins↗
PubMed2000

Real-time electrochemical imaging using an individually addressable multi-channel electrode.

We developed a real-time electrochemical imaging method that uses a multiple enzyme-modified microelectrode. The method will enable the investigation of the functions of biological materials and cells. To test its effectiveness, we imaged the two-dimensional concentration distribution for hydrogen peroxide and L-glutamate in a standard solution. The multiple electrode consists of an 8 x 8 array of 30 x 30 microm2 carbon micro electrode. Each electrode was connected to a 64-channel potentiostat that could apply a potential to all electrodes at the same time. The multiple electrode was coated with an Os-polyvinylpyridine based polymer (Os-gel) containing horse radish peroxidase (HRP) to detect hydrogen peroxide, which is a very common product of oxidase enzyme. When measuring glutamate, which is a well-known neurotransmitter in the mammalian central nerve system, we modified the electrode with a bilayer of Os-gel-HRP and GluOx. The detection limit of our method was 1 microM and images of the glutamate concentration-distribution changes induced by local injection of glutamate through microcapillary were obtained in real time.

Amino Acid Oxidoreductases↗
PubMed2000

Vanishing bile duct syndrome associated with chronic EBV infection.

We reported here an adult patient with vanishing bile duct syndrome due to chronic EBV infection. A 22-year-old male was admitted to a nearby hospital complaining of a sore throat and jaundice. He received a high dose of prednisolone for bile stasis of acute viral hepatitis. However, the hepatitis did not improve, and he was transferred to our hospital. He had exhibited jaundice for one year as well as hemophagocytic syndrome and intestinal perforation. Subtotal intestinal resection was successfully performed. Three follow-up biopsied liver specimens indicated vanishing bile duct syndrome. Positive results of EBV-DNA in his serum and mRNA of EBV by in situ hybridization of his liver indicated that massive doses of prednisolone caused chronic EBV infection and vanishing bile duct syndrome.

Adult↗
PubMed2000

Reconstitution of gammadelta T cell repertoire diversity after human allogeneic hematopoietic cell transplantation and the role of peripheral expansion of mature T cell population in the graft.

We have examined the reconstitution of gammadelta T cell repertoire diversity after human allogeneic hematopoietic cell transplantation using a polymerase chain reaction (PCR)-based complementarity-determining region (CDR) 3 size spectratyping and DNA sequencing. The CDR3 complexity in the variable region of the T cell receptor (TCR)-delta chain was different amongst the individuals studied. Furthermore, CDR3 size distribution patterns of allogeneic hematopoietic cell transplant recipients were almost completely recovered by a few months after transplantation. In some patients, clonal predominance of the TCRDV1+ T cells became evident during the period after transplantation. In one particular donor/recipient pair, clonal predominance of TCRDV1+ T cells was already present in blood lymphocytes of the donor, and was also observed in the recipient after transplantation. Using this donor/recipient pair, we have questioned whether gammadelta T cell regeneration occurs via the peripheral expansion of mature T cells in the graft. In the donor lymphocytes, two expanding gammadelta T cell clones, which were demonstrated by CDR3 sequences of the TCR-delta chain, were recognized. These two clones were identified in the T cells from the recipient post transplant, but not before transplantation. One of the two clones was still detectable 1(1/2) years after the transplant procedure. These results strongly suggest that peripheral expansion of mature T cells in the graft is the principal pathway of gammadelta T cell regeneration after allogeneic hematopoietic cell transplantation in adults.

Adolescent↗
PubMed2000

Mannose binding lectin (MBL) gene mutation is not a risk factor for systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) in Japanese.

Mannose binding lectin (MBL) deficiency may be associated with increased susceptibility to infection and autoimmune disorders, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In the present study, we performed for the first systematic search for mutations in all the four exons of the MBL gene using polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) analysis. Of 49 healthy Japanese individuals studied, only the previously reported mutation at the codon 54 (substitution from Gly to Asp; G54D) was identified. The allele frequencies of G54D in 105 healthy Japanese individuals, 95 SLE patients and 59 RA patients, were 0.233, 0.226 and 0.178, respectively, which were not significantly different. In addition, two polymorphisms at positions of -550 and -221 in the promoter region were not associated with SLE and RA. It is unlikely that MBL deficiency plays a major role in the pathogenesis of SLE and RA in Japanese.

Alleles↗
PubMed2000

Restricted usage of T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires after human allogeneic haematopoietic transplantation.

We analysed T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires in peripheral blood mononuclear cells (PBMCs) from 34 recipients of allogeneic bone marrow transplantation (allo-BMT), seven of allogeneic peripheral blood stem cell transplantation and 19 of autologous peripheral blood stem cell transplantation using the quantitative microplate hybridization assay. TCR usage skewed at an early period (6-7 weeks) after BMT. The change was more apparent in allogeneic recipients than in autologous recipients. In particular, a predominant increase was detected in the frequency of VA1-4 (26%, 11 of 41 recipients), VA3-1 (32%) and VB24-1 (28%). Interestingly, acidic amino acid residues frequently followed the arginine residue in complementarity-determining region 3 of BV24S1. We further examined the extent of skew using samples obtained at serial time points after transplantation. The normalization of skewed repertoires occurred over a long period of time (> 8 years). There was a significant difference in the rate of normalization of skewed TCR repertoires between adult and child recipients (P < 0.05). The results suggest that these T cells may have expanded in response to allogeneic antigens, such as miHA (minor histocompatibility antigen), and that altered repertoires are eventually normalized by T-cell regeneration via a thymic-dependent pathway in children.

Adolescent↗
PubMed2000

Delayed recovery of CDR3 complexity of the T-cell receptor-beta chain in recipients of allogeneic bone marrow transplants who had virus-associated interstitial pneumonia: monitor of T-cell function by CDR3 spectratyping.

BACKGROUND: In the T-cell receptor (TCR)-beta chain, complementary-determining region 3 (CDR3) contains specific peptide sequences essential for recognition. Diversity of this region is considered to contribute to immunocompetence in humans. OBJECTIVE: The purpose of this study was to define the process of reconstitution of CDR3 complexity of the TCR-beta chain after allogeneic bone marrow transplantation and to investigate the association between host immunocompetence and CDR3 complexity. METHODS: Diversity of the CDR3 region of the TCR-beta chain was examined by CDR3 size distribution analysis with the use of an automated DNA sequencer. RESULTS: Reconstitution of the alphabeta T-cell repertoire and CDR3 diversity was incomplete for at least 2 months after bone marrow transplantation. Delayed reconstitution of T-cell diversity was more marked in immunocompromised hosts. Unlike the situation in patients who received allogeneic bone marrow grafts, the recovery of CDR3 complexity was almost perfect by 2 months after transplantation in patients who received allogeneic blood stem cells. Clonal expansion of alphabeta T cells after allogeneic bone marrow transplantation was readily detected by CDR3 size spectratyping analysis. CONCLUSION: PCR-based CDR3 size spectratyping may be a useful tool for clinically monitoring immune reconstitution after allogeneic bone marrow transplantation.

Adolescent↗
PubMed2000

Retroperitoneoscopic excision of a mesenteric cyst.

Mesenteric cysts are rare intra-abdominal lesions. We present a case of a mesenteric cyst that was discovered by abdominal computed tomography (CT) and excised by retroperitoneoscopic surgery. There have been 10 reports of excision of mesenteric cysts by laparoscopy in the literature, but retroperitoneoscopic resection of such cysts has not been reported. This case suggests that when a mesenteric cyst arises from the ascending or descending colon, the retroperitoneal approach has a lower risk of traumatizing the bowel than does the laparoscopic intra-abdominal approach, and it does not have to compress other intra-abdominal organs.

Adult↗
PubMed2000

Analysis of p53 tumour suppressor gene somatic mutations in rheumatoid arthritis synovium.

OBJECTIVE: In order to study the role of the p53 tumour suppressor gene in the proliferation of rheumatoid arthritis (RA) synovium, we analysed the mutation of p53 in the synovial fibroblast-like type B synoviocyte from RA patients. METHODS: Synovial fibroblast-like type B synoviocytes were prepared from the synovial tissues from nine Japanese patients with RA. The p53 cDNA region from exons 4-11 was screened for mutations by the streamlined mutation detection method in which polymerase chain reaction (PCR) products are post-labelled and are analysed by automated capillary electrophoresis using single-strand conformation polymorphism conditions, followed by direct sequencing of the subclones of the PCR products. RESULTS: p53 mutation with possible functional alteration was detected in four of the nine RA patients (44.4%). Of a total of 262 p53 cDNA subclones, 10 subclones were carrying 10 p53 mutations, eight of which were associated with amino acid alterations or protein truncation. Of the p53 functional mutations, a substitution of Gly at amino acid residue 245 to Asp (G245D) was identified in two patients in three subclones. G245D was the first mutation that was recurrently identified in different RA individuals. G245D is also one of the relatively common mutations in human cancers. CONCLUSIONS: In some patients with RA, dysfunction of p53 might play a role in the proliferation of the synovial tissue. G245D mutation might especially need further study as it is the first recurrently identified p53 mutation in RA and is also one of the frequently identified mutations in human cancers.

Arthritis, Rheumatoid↗
PubMed2000

Establishment and characterization of a colonic epithelial cell line MCE301 from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene.

We produced an immortalized colonic epithelial cell line, MCE301, using fetal mice transgenic for the temperature-sensitive simian virus 40 large T-antigen gene. MCE301 cells showed epithelial-like morphology and maintained tight connections with neighboring cells. The cells grew at a permissive temperature (33 degrees C), but the growth of the cells was significantly prevented at the nonpermissive temperature (39 degrees C). The cells expressed large T-antigen at 33 degrees C but not at 39 degrees C. MCE301 cells were not transformed, as judged by the absence of anchorage-independent growth in soft agar gel and lack of tumor formation in nude mice. Electron microscopic studies showed that the cells formed microvilli-like structures on the cell surface and junctional complexes such as tight junctions and desmosomes between the cells. The cells expressed cytosketal (acidic cytokeratins and actin), basement membrane (laminin and collagen type IV) and junctional complex proteins (ZO-1 and desmoplakin I + II), as judged by specific antibodies. Fetal bovine serum, epidermal growth factor, insulin-like growth factor and insulin significantly increased the cell growth at 33 degrees C. Moreover, MCE301 cells expressed colonic mucin Muc2 mRNA as demonstrated by reverse transcriptase-polymerase chain reaction, indicating that the cells originate from mucus-secreting cells. Alkaline phosphatase, a brush border-associated enzyme, was detected in the cells. Sodium butyrate (2 mM), an inducer of cellular differentiation, markedly elevated alkaline phosphatase activity. Thus, the present mouse colonic epithelial cell line MCE301 possessing these unique characteristics should provide a useful in vitro model of colonic epithelium.

Alkaline Phosphatase↗
PubMed2000

Severe thrombocytopenia caused by digitoxin intoxication in a patient with heart failure associated with Sjögren's syndrome.

Congestive heart failure (CHF) related to Sjögren's syndrome is extremely rare. This report concerns a patient who presented with CHF and severe thrombocytopenia (5,000/microl). Serum concentrations of K, Mg and digitoxin were 3.2mmol/L, 1.4mg/L and 57.2ng/ml, respectively. Digitoxin intoxication was evident, seemingly evoked by hypokalemia, hypomagnesemia, hepatorenal dysfunction and hypothyroidism. The severe thrombocytopenia was considered to have been caused by this intoxication, as it disappeared soon after the digitoxin was discontinued and potassium was supplemented.

Cardiotonic Agents↗
PubMed2000

Immunoreactive pit-1 protein in hyperplastic pars intermedia induced by calcitonin of the rat pituitary gland.

To elucidate the effects of synthetic salmon calcitonin (sCT) on the cells in the rat pituitary gland, we histopathologically and immunohistochemically examined the early changes after 4 or 13 weeks treatment with sCT 120 IU/kg. Focal proliferative lesions of the anterior pituitary glands were consistently found after treatment with sCT for 13 weeks. Histologically, the cells with the focal proliferative lesions were classified into the following three groups: 1) enlarged basophilic cell focus, 2) vacuolated cell focus and 3) chromophobe cell focus. These focal proliferative lesions had positive staining only for the alpha-subunit and failed to show Pit-1 protein immunoreactivity. The sCT treatment also increased the thickness of the pars intermedia. Hypertrophy of the pars intermediate cells was characteristically seen. Furthermore, Pit-1 protein immunoreactivity was clearly detected in the nuclei of the hyperplastic pars intermediate cells. All pars intermediate cells were equally stained by alpha- or beta-MSH and beta-endorphin in both vehicle- and sCT-treatment. No difference was seen. These findings strongly suggest a very close relationship between Pit-1 protein immunoreactivity and cellular proliferation induced by sCT.

Animals↗
PubMed2000

Hypercalcemia induced with the plasma levels of parathyroid hormone-related peptide in multiple myeloma.

A 69-year-old man visited our department of neurology with symptoms of paresthesia on the lower extremities and lumbago. Biochemical examination of serum samples showed hypercalcemia (serum concentration 15.6 mg/dl). The levels of intact parathyroid hormone (i-PTH) and 1,25-dihydroxyvitamin D were suppressed, whereas parathyroid hormone-related peptide (PTHrP) was elevated up to 5.4 pM (normal range: below 0.6 pM). Additionally, bone survey revealed a punched-out lesion in radiological examinations of the skull. Bone marrow aspiration demonstrated many atypical plasma cells suggesting multiple myeloma. Nephrogenous cyclic adenosine monophosphate (cAMP), urinary deoxypyridinoline, plasma interleukin 6 (IL-6) and transforming growth factor beta (TGF beta) concentrations were elevated, whereas % of renal tubular reabsorption of phosphate (%TRP) was decreased. The immunohistochemical results demonstrated the expression of PTHrP in atypical plasma cells. These data indicated that hypercalcemia complicating multiple myeloma causes an elevation of renal calcium reabsorption and an increase of bone resorption mediated by PTHrP action.

Aged↗
PubMed2000

[Acute eosinophilic pneumonia induced by cigarette smoking].

The subject was a 24-year-old man who presented with acute fever, dry cough, and dyspnea. Chest X-ray films revealed diffuse infiltrates in both lungs. Bronchoalveolar lavage fluid specimens contained an increased number of eosinophils. Transbronchial lung biopsy specimens demonstrated the infiltration of eosinophils into alveolar walls and air spaces. These findings were consistent with acute eosinophilic pneumonia. The patient recovered without medical treatment. Eight days prior to admission, he had resumed smoking after 3 years of abstention. It was suggested that the cause of acute eosinophilic pneumonia in this case was associated with the resumption of smoking. To confirm that association, a smoking challenge test is usually necessary. However, similar symptoms also developed later, after the patient was passively exposed to cigarette smoke. Therefore, we concluded that smoking was probably the etiologic agent of his illness.

Acute Disease↗
PubMed2000

[Pulmonary complications after allogeneic hematopoietic stem cell transplantation].

We investigated the occurrence of pulmonary complications in patients who underwent allogeneic hematopoietic stem cell transplantation at our institution. Pulmonary complications were observed in 12 out of 60 patients. Interstitial pneumonia developed in 12 cases: 7 idiopathic, 2 cytomegalovirus-associated, 1 P. carinii, 1 HSV, and 1 HHV-6-associated. HSV- and HHV-6-associated pneumonias were exhibited 100 days after transplantation. PCR analysis was diagnostically useful for detection of viral DNA in bronchial alveolar lavage fluid. Respiratory disease with airway obstruction was observed in 4 patients with chronic graft-versus-host disease, and all 4 had a history of interstitial pneumonia. Three patients died of respiratory failure. Mycobacicrium avium complex was detected in 2. Exacerbation of respiratory failure may be associated with mycobacterial infection.

Adolescent↗