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K Imai

Publications and source records attributed to K Imai.

At least 127 records · Page 7Linked to original sources
PubMed2001

Comparative analysis of the genomic organization of Pax9 and its conserved physical association with Nkx2-9 in the human, mouse, and pufferfish genomes.

As a first step towards the identification of cis-regulatory elements of Pax9 by means of comparative genomics, we have analyzed genome regions encompassing the Pax9 gene in three vertebrate species, humans, mice (Mus musculus), and the Japanese pufferfish (Fugu rubripes). We show the genomic organization of Pax9 and its physical association with Nkx2-9 conserved in the three species. We discuss about possible implications of the conserved synteny between Pax9 and Nkx2-9 in a context of vertebrate evolution. This report also includes the first description of the primary structures of Fugu Pax9 and Nkx2-9. Furthermore, we report the identification of a novel upstream exon and putative transcription start sites in mouse Pax9. Our results suggest that transcription of Pax9 may be initiated at two alternative start sites and driven by TATA-less promoters.

Amino Acid Sequence↗
PubMed2001

Isolation and characterization of the fission yeast gene Sprpa12+ reveals that the conserved C-terminal zinc-finger region is dispensable for the function of its product.

RNA polymerase I of Saccharomyces cerevisiae contains a small subunit, A12.2, encoded by RPA12, that was previously shown to be involved in the assembly and/or stabilization of the largest subunit, A190, of RNA polymerase I. To examine whether an equivalent subunit is present in another eukaryotic RNA polymerase I, we have cloned a Schizosaccahromyces pombe cDNA that is able to complement the rpa12 mutation in S. cerevisiae. The gene, named Sprpa12+, encodes a polypeptide of 119 amino acids that shows 55% identity to S. cerevisiae A12. 2 over its entire length, including two zinc-finger motifs. Disruption of the chromosomal Sprpa12+ gene shows that it is required for growth at higher temperatures but not at lower temperatures. Expression of Sprpa190+/nuc1+, which encodes the largest subunit of the S. pombe RNA polymerase I, from a multicopy plasmid can partially suppress the growth defect of the Sprpa12 disruptant at higher temperatures. These findings suggest that A12.2 subunit is functionally and structurally conserved between S. cerevisiae and S. pombe. Finally, the analysis of mutants suggests that SpRPA12 requires the zinc-finger domain in the N-terminal region but not the one in the C-terminal region for its function.

Amino Acid Sequence↗
PubMed2001

Expression of placental lactogen and cytokeratin in bovine placental binucleate cells in culture.

Binucleate cells are present in ruminant placenta and play an endocrine role in the production of many hormones during pregnancy. We isolated and cultured binucleate cells from bovine placenta at middle to late gestation and characterized these cells using immunofluorescence techniques. Enriched preparations of binucleate cells were obtained using Percoll density gradient centrifugation following collagenase digestion. Binucleate cells in culture preferentially attached to collagen-coated dishes rather than to noncoated plastic dishes. The cells gradually extended their edges on collagen substrata, and finally assumed a flattened morphology. Antibodies to placental lactogen (PL) and pregnancy-associated glycoprotein-1 (PAG-1) specifically stained the majority of round binucleate cells, but not the flat cells. We found that PL-positive binucleate cells were consistently devoid of cytokeratin. In contrast, cytokeratin was expressed in PL-negative binucleate cells as well as mononuclear epithelial cells. Furthermore, the PL-negative flat binucleate cells also developed intense cytokeratin networks in the cytoplasm. These results indicate that cytokeratin expression is inversely proportionate to that of PL in cultured binucleate cells. We conclude that downregulation of cytokeratin in binucleate cells is a function of the state of cellular differentiation.

Animals↗
PubMed2001

Fatal acute hepatic failure induced by danazol in a patient with endometriosis and aplastic anemia.

We describe a 47-year-old woman with severe aplastic anemia with genital bleeding who developed acute severe hepatitis after the administration of danazol while she was receiving cyclosporin. She had been diagnosed with severe aplastic anemia 1 year previously and, while hospitalized, had received methyl prednisolone pulse therapy, which was not successful. She was then referred to our hospital. She was treated with antithymocyte globulin, cyclosporin, granulocyte colony-stimulating factor, and methyl prednisolone; a good response was achieved after 3 months of this therapy. Subsequently, oral administration of cyclosporin was continued, but she was readmitted to our hospital when pancytopenia gradually developed and the genital bleeding recurred. Danazol was administered for pancytopenia and endometriosis. Four days after the first administration of danazol, epigastric pain occurred, and the danazol was stopped. Eighteen days after the first danazol administration, very severe hepatic injury occurred abruptly. The patient died of hepatic failure. Postmortem examination revealed centrilobular massive necrosis of the liver. Danazol was implicated as the agent responsible for causing the hepatic failure. Drug interactions between danazol and cyclosporin may cause adverse effects.

Anemia, Aplastic↗
PubMed2001

Measurement of circulating biliary glycoprotein (CD66a) in liver diseases.

PURPOSE: Biliary glycoprotein (BGP), a member of the carcinoembryonic antigen (CEA) gene family, is produced by hepatocytes, and is suggested to function as a cell adhesion molecule, mouse hepatitis virus receptor, and tumor suppressor. Our aim was to establish an enzyme immunoassay for circulating BGP and to study its significance in liver diseases. METHODS: For enzyme immunoassay, a monoclonal antibody (mAb), TS135, which recognizes BGP was used as a catcher, and biotin-labeled polyclonal anti-CEA antibodies were used as a tracer. Seventy-six serum specimens obtained from patients with various liver diseases were submitted to the assay. RESULTS: The incidence of positivity for antigen TS135 in the serum samples of the 76 patients was 57.9%. The most significant correlation among conventional liver function tests was found between antigen TS135 and gamma-glutamyl transpeptidase (gamma-GTP). However, among the 56 patients whose serum antigen TS135 and gamma-GTP levels could be measured simultaneously, 5 were antigen TS135-positive and gamma-GTP-negative (8.9%) and 6 were antigen TS135-negative and gamma-GTP-positive (10.7%). The increased serum level of antigen TS135 in 6 cholangiocellular carcinoma (CCC) patients led us to the immunohistochemical study of CCC, in which 8 of the 8 tissue specimens tested were positive for mAb TS135, indicating the production of the antigen from CCCs. CONCLUSIONS: This preliminary study suggests that the circulating antigen TS135 level correlates with gamma-GTP in liver diseases, but that TS135 may also have a unique significance, different from that of gamma-GTP, as a liver function test.

Adult↗
PubMed2001

Jejunal carcinoid tumor mimicking leiomyosarcoma: preoperative diagnosis by endoscopic biopsy.

Primary carcinoid tumor of the jejunum is rare, and is an unusual cause of massive gastrointestinal bleeding. A case of primary jejunal carcinoid tumor in a 39-year-old woman who presented with massive hematochezia is described. Both upper and lower gastrointestinal endoscopies showed no abnormalities. An abdominal computed tomographic scan, small-bowel barium contrast studies, and small-bowel endoscopy showed a subserosal mass, of 5 x 4 cm, with a cavity suggesting central necrosis, and a deep mucosal ulceration, located in the proximal jejunum. Although these clinical presentations were strongly suggestive of a leiomyosarcoma, histologic examination of biopsy samples obtained by enteroscopy confirmed the diagnosis of jejunal carcinoid tumor. The patient underwent radical jejunal resection and recovered uneventfully. In spite of the large size of the tumor, there was one solitary lymph node metastasis, but no evidence of liver metastases. This kind of jejunal carcinoid tumor, presenting with massive gastrointestinal bleeding and a subserosal bulky growth mimicking a leiomyosarcoma, has not been reported previously. Moreover, this is a rare case of a jejunal carcinoid which was diagnosed preoperatively by small bowel-endoscopic biopsy.

Adult↗
PubMed2001

Predominance of G3B and G14 equine group A rotaviruses of a single VP4 serotype in Japan.

A total of 65 equine group A rotaviruses (GAR) isolated from diarrheal foals at 48 farms in Hokkaido, Japan, between 1996 (29 isolates) and 1997 (36 isolates) were characterized for their VP7 and VP4 serotypes by PCR, nucleotide sequencing, and virus neutralization (VN) tests. By PCR VP7 typing, all isolates were classified as G3 or G 14, and the predominant serotype in each year was G3 (86%) in 1996 and G14 (53%) in 1997. VN tests with these 20 isolates randomly selected confirmed the specificity of PCR on the bases of complete agreement of the results in these methods (9 G3 and 11 G14), and revealed that all 9 G3 isolates were subtype G3B. There were five differing amino acid residues in three VP7 antigenic regions between subtypes G3A and G3B. Antiserum to a baculovirus recombinant that expressed P[12] VP4 neutralized all isolates and P[12] reference strains. These results suggest that genotype P[12] GAR belong to a single VP4 serotype, and that one VP4 and two VP7 serotypes (G3B and G14) of GAR were predominant in the equine population in Japan.

Amino Acid Sequence↗
PubMed2001

Association analysis of polymorphisms in the prepronociceptin gene and schizophrenia.

The human prepronociceptin (ppNoc) gene is located on chromosome 8p21, and several linkage studies have suggested that the susceptibility locus for schizophrenia is present in this chromosomal region. We investigated genetic variations in the promoter and coding regions of the ppNoc gene to determine if there may be an association between naturally occurring mutations and the manifestation of schizophrenia. Association analyses for the variations found were conducted between 87 unrelated schizophrenic patients and 100 healthy controls. Polymorphisms were found at both the -503 locus (G/A) in the promoter region and the 353 locus (Ala118Gly) in exon 3. Additionally, rare variants were identified at the -261 locus (A/G) in the promoter region, the 515 locus (Gln172Arg) in exon 3, and the 561 locus (G/A) in the untranslated region of exon 3. A significant difference was observed in allele frequency at the 353 locus between controls and patients with continuous-course schizophrenia (P = 0.0237), and between patients with and without prominent negative symptoms (P = 0.0201). However, neither difference was significant after Bonferroni correction. In addition, there were no significant differences in genotype and allele frequencies at either the -503 or 353 locus between the control group and patients with schizophrenia. These results suggest that ppNoc gene polymorphisms have no association with schizophrenia.

Adult↗
PubMed2001

Foveal translocation with scleral imbrication in patients with myopic neovascular maculopathy.

PURPOSE: To report our surgical results of foveal translocation with scleral imbrication in patients with myopic neovascular maculopathy. DESIGN: Noncomparative, interventional, consecutive case series. METHODS: Ten eyes of 10 myopic patients with subfoveal neovascular membranes that had undergone foveal translocation with scleral imbrication were recruited for this retrospective study. Inclusion criteria were myopia 6.0 diopters or greater in refractive error (or axial length 26.5 mm or longer), subfoveal choroidal neovascularization, and preoperative best-corrected visual acuity of 20/100 or worse. None of these eyes had undergone prior laser photocoagulation or submacular surgery. The main outcome measures were surgical complications and postoperative visual function. RESULTS: Postoperatively, visual acuity had improved more than 3 lines in the logarithm of minimum angle of resolution (logMAR) measurement in all eyes. The mean preoperative, postoperative best, and final visual acuity were 0.12, 0.59, and 0.51, respectively. Of the 10 eyes, six achieved a postoperative final visual acuity of 20/40 or better. The mean postoperative foveal displacement was 0.78 disk diameter (range, 0.3--1.3 disk diameter). Two patients underwent a reoperation because of insufficient foveal displacement. Furthermore, one of these two patients required a third operation to reduce an excessive retinal fold involving the fovea induced by the second surgery. Of the 10 patients, two noted transient diplopia. This complaint, however, resolved over time as suppression developed. Although unintentional iatrogenic retinal tears formed intraoperatively in two eyes, these were successfully treated without serious complications. Postoperatively, mild retinal pigment epithelial changes were observed in all cases, but none led to significant deterioration of visual acuity during the follow-up period. All patients but one were followed for a minimum of 6 months. CONCLUSIONS: In eyes with myopic neovascular maculopathy, foveal translocation with scleral imbrication may be useful in improving visual acuity. Further refinements in surgical technique and assessment of the long-term complications will be needed to make this procedure safer and more useful.

Adult↗
PubMed2001

Clinical analysis of results of a simple left atrial procedure for chronic atrial fibrillation.

BACKGROUND: We have performed a simple left atrial procedure for eliminating chronic atrial fibrillation (AF) associated with mitral valve disease. This article analyzes the midterm results of this procedure. METHODS: Thirty-two patients were enrolled in this study concomitant with mitral valve operations. Patients were divided into two groups (AF- and AF+). We examined the efficacy of this operation and atrial function for more than 12 months of follow-up. RESULTS: In a total of 98.5 patient years of follow-up, AF was absent 3 years after operation in 74%. Of preoperative and intraoperative variables, only long duration o

Aged↗
PubMed2001

Efficacy of pulmonary vein isolation for the elimination of chronic atrial fibrillation in cardiac valvular surgery.

BACKGROUND: Haissaguerre and colleagues emphasize the importance of the pulmonary veins as a source of ectopic foci for initiating paroxysmal atrial fibrillation (AF). We hypothesized that ectopic foci from the pulmonary veins could also act as drivers for maintaining chronic AF, and that surgical ablation of the pulmonary vein orifices could terminate chronic AF. METHODS: Using a computerized 48-channel mapping system, we performed intraoperative atrial mapping in 12 patients with chronic AF associated with mitral valve disease. Patient age ranged from 24 to 82 years (mean, 60.4 years). AF duration ranged from 3 to 240 months (mean, 92+/-84 months). Simple surgical isolation of the pulmonary vein orifices was performed during the mitral valve operation. RESULTS: Regular and repetitive activation was found in the left atria of 9 out of 12 patients, and irregular and chaotic activation was found in both atria of 3 out of 12 patients. Chronic AF in the 9 patients (75%) with regular and repetitive activation of their left atria was successfully treated by a simple surgical isolation of the pulmonary vein orifices. The other 3 patients did not recover sinus rhythm after this procedure. In 1 case of recurrent AF, the patient recovered sinus rhythm during the follow-up period (AF-free rate, 83%). CONCLUSIONS: Surgical ablation of the pulmonary vein orifices was effective in the treatment of chronic AF associated with mitral valve disease. Intraoperative mapping may be useful in predicting the efficacy of a single pulmonary vein orifice isolation procedure.

Adult↗
PubMed2001

Mutational analysis of MECP2 in Japanese patients with atypical Rett syndrome.

Rett syndrome (RTT) is one of the most common neurodevelopmental disorders in females. Recently, this disease was found to be linked with mutations in the methyl-CpG-binding protein 2 gene (MECP2) and various mutations have been reported. To explore the spectrum of phenotypes resulting from MECP2 mutations, we searched for mutations in the MECP2 of 20 Japanese patients who had more than five of the criteria necessary for RTT diagnosis proposed in 1988 (The Rett Syndrome Diagnostic Criteria Work Group, Ann Neurol 23 (1988) 425) and compared the phenotype between patients with and without mutation by giving a score to each diagnostic criterion. We found four missense mutations (T158M, R133C, Y120D, and R306C), two nonsense mutations (R168X and R270X), one frameshift (726delAAAG) mutation, and one polymorphism (A201V) in ten patients (50%). This included two novel mutations (726delAAAG and Y120D). All mutations were found in the highly conserved methyl-binding and transcription repression domains. Comparison of the mean total diagnostic criterion score of the groups with and without mutation did not reveal any statistically significantly difference (P=0.28). The only difference between the groups, which was of borderline significance (P=0.051), was the sum of the scores for diagnostic criteria 2 (apparently normal psychomotor development through the first 6 months) and 5 (loss of acquired purposeful hand skills between the ages of 6 and 30 months). From these results, it is suggested that the clinical phenotype of RTT is variable and it is important to investigate the MECP2 genotype for patients having more than five criteria and not only in those who exhibit all RTT diagnostic criteria. The diagnosis of RTT is clinically difficult before 3 years of age, especially in atypical cases, but molecular analysis of the MECP2 will assist diagnosis in some patients.

Adolescent↗
PubMed2001

A case of MERRF associated with chronic pancreatitis.

We report the first case to our knowledge of chronic pancreatitis associated with mitochondrial encephalopathy with the A8344G mitochondrial DNA (mtDNA) mutation. This 10-year-old-girl had suffered from recurrent abdominal pain with elevated serum amylase and lipase since the age of 6, and easy fatigability, tremor and astatic seizures since the age of 8. A biopsy of quadriceps muscle revealed ragged-red-fibers and cytochrome c oxidase deficiency. Analysis of mtDNA in peripheral blood identified an A8344G mutation in the mitochondrial tRNA(Lys) gene. Taken together with physical signs of myoclonic seizures and cerebellar dysfunction, we diagnosed her as myoclonic epilepsy with ragged-red fibers associated with chronic pancreatitis. Although no association between mitochondrial disease and pancreatitis has yet been established, this case suggests it is necessary to consider the participation of mitochondrial abnormality in the pathogenesis of recurrent pancreatitis.

Brain↗
PubMed2001

Adenovirus-mediated transfer of the p53 family genes, p73 and p51/p63 induces cell cycle arrest and apoptosis in colorectal cancer cell lines: potential application to gene therapy of colorectal cancer.

p53 gene therapy is being tested clinically for the treatment of human cancer, however, some cancer models (in vivo and in vitro) are resistant to p53. To explore the potential use of two p53 homologues, p73 and p51/p63, in cancer gene therapy, we introduced p53, p73 and p51/p63 into colorectal cancer cell lines via adenoviral vectors, and compared their effects on cell growth. Among 10 cell lines tested, six cell lines displayed a similar response following transduction of p53, p73beta or p51A/p63gamma; two lines underwent cell-cycle arrest, three lines exhibited apoptosis and one line showed no-effect following transduction. The effect on cell-cycle progression was variable in the other four cell lines. Interestingly, three cell lines were resistant to p53-mediated apoptosis, including two lines having endogenous wild-type p53 alleles, but underwent apoptosis after transduction of p73beta or p51A/p63gamma. Similar to p53, transduction of p51A/p63gamma induced extensive apoptosis when combined with adriamycin or X-radiation in SW480 cells, which are normally resistant to apoptosis. Transduction of p73beta and p51A/p63gamma also reduced the tumorigenicity of two colorectal cancer cells in vivo. These results suggest that adenovirus-mediated p73beta and p51A/p63gamma transfer are potential novel approaches for the treatment of human cancers, particularly for tumors that are resistant to p53 gene therapy.

Adenoviridae↗
PubMed2001

A method for the measurement of catechol-O-methyltransferase activity using norepinephrine, an endogenous substrate.

We propose a highly sensitive method for the measurement of catechol-O-methyltransferase (COMT) activity with norepinephrine (NE), an endogenous native substrate. The product, normetanephrine, was determined by high-performance liquid chromatography (HPLC)-peroxyoxalate chemiluminescence reaction detection or, if required, less sensitive fluorescence detection. For the measurement of membrane-bound (MB)-COMT activity in the rat erythrocyte, the HPLC-peroxyoxalate chemiluminescence reaction detection was employed. Soluble (S)- and MB-COMT activities in the rat erythrocyte were 22.9 +/- 2.5 and 4.62 +/- 1.23 pmol min-1 (mg protein)-1, respectively (n = 5). The Km values obtained for S- and MB-COMT were 366 +/- 31 mumol l-1 and 12.0 +/- 1.1 mumol l-1, respectively (n = 5), suggesting that the use of NE as a substrate would give more precise information on the role of both isoenzymes. However, with dihydroxybenzoic acid as an artificial substrate, the Km values for S- and MB-COMT were similar, with values of 69.2 +/- 11.4 mumol l-1 and 72.2 +/- 9.2 mumol l-1, respectively. The proposed method is thought to be useful for the measurement of both S-COMT and MB-COMT activities, and would give us critical information on the role of metabolism of catecholamines in rat tissues.

Animals↗