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Biomedical subjects

T Okazaki

Publications and source records attributed to T Okazaki.

At least 163 records · Page 9Linked to original sources
PubMed1997

The activity of 17alpha-hydroxylase/C17-C20 lyase in the ovaries of immature hypophysectomized rats treated with recombinant FSH combined with various doses of human chorionic gonadotropin.

The activity of 17alpha-hydroxylase/C17-C20 lyase (17alpha-hydroxylase) in the ovaries and steroid hormone levels in the plasma were studied in immature hypophysectomized rats (IH-rats) treated with human recombinant follicle-stimulating hormone (rec-FSH) alone or combined with various doses of human chorionic gonadotropin (hCG). Eleven days after hypophysectomy, rats were given rec-FSH alone (total dose, 40 IU), or combined with various doses (0.1 to 10 IU in total) of hCG, twice daily for 4 days. Plasma levels of progesterone, testosterone and estradiol, and ovarian 17alpha-hydroxylase activity were measured 18 h after the last injection. Histology showed that the ovaries treated with rec-FSH alone had large antral follicles, the theca interna cells of which were small in size compared with those treated with rec-FSH combined with hCG. The activity of 17alpha-hydroxylase in the ovaries of IH-rats treated with rec-FSH alone was lower than that in the control IH-rats. It was markedly increased by treatment with rec-FSH combined with 1 or 10 IU hCG. Immunohistochemistry revealed that 17alpha-hydroxylase was localized only in the oocyte in the ovaries of control IH-rats and those treated with rec-FSH alone. When the IH-rats were treated with rec-FSH plus hCG, the number of immunopositive theca interna cells and interstitial cells, and their immunointensity were increased in an hCG dose-dependent manner. The plasma estradiol levels in the IH-rats treated with rec-FSH alone were low, but significantly higher than those in the control IH-rats, and estradiol levels were noticeably elevated in IH-rats treated with rec-FSH plus hCG. These results suggest that a synergism between hCG (LH) and FSH is essential for follicular development and steroidogenesis in the ovaries, implying paracrine effects among granulosa cells, theca cells and probably oocytes. The functional significance of 17alpha-hydroxylase in the oocytes is discussed in relation to estradiol production.

Animals↗
PubMed1997

[A case of pulmonary tuberculosis complicated with gingival lesions].

A case of secondary gingival tuberculosis is presented. The case is 51 year-old male who had been suffering from undetected pulmonary tuberculosis visited a dentist because of chronic periodontal inflammation around the gingiva of the right upper and left lower molar teeth lasting for one year. The lesions remained unchanged and painful granulomatous swelling sustained in spite of the conservative treatment. The case was treated with the extraction of six teeth due to continued toothache. By pathohistological examination of gingiva and chest X-ray examination, the case was diagnosed as tuberculosis. Chest roentgenogram showed active pulmonary tuberculosis, and bacteriological examination of sputum showed tubercle bacilli. The administration of INH, RFP and EB was started, and the response to the treatment was good and the pain in the gingiva disappeared within three weeks. Secondary gingival tuberculosis is manifested as local granulomatous lesions with severe pain. The incidence of gingival tuberculosis is very rare, but we have to keep in mind that the oral tuberculosis secondary to pulmonary tuberculosis could occur.

Gingival Diseases↗
PubMed1997

[Aortic arch surgery in the elderly].

A consecutive series of 16 patients over 75 years old who underwent aortic arch operations with hypothermic selective cerebral perfusion from 1994 to 1997 was analyzed. These patients (group O) was compared with 18 patients aged from 70 to 74-year-old (group M) and 38 patients under the age of 69 (group Y) who underwent aortic arch operation during the same period. There were 5 males and 11 females with a mean age of 77.8 years (range 75 to 86) in group O. Twelve patients were in aortic dissection and 4 patients were in atherosclerotic aneurysms. There were 5 hospital deaths (31.2%) in group O, 2 (11.1%) in group M and 2 (5.3%) in group Y. There was significant difference in hospital mortality rate between group O and group Y. Cerebral complication occurred in 2 patients (12.5%) and postoperative respiratory failure occurred in 7 (47%) in group O. Aortic arch operations for the elderly patients can be performed with increased but operative mortality in the elderly patients remains high. In this study, we discussed that influence of risk factors on the operative result and operative indication in the elderly patients.

Age Factors↗
PubMed1997

Automatic construction of knowledge base from biological papers.

We designed a system that acquires domain specific knowledge from human written biological papers, and we call this system IFBP (Information Finding from Biological Papers). IFBP is divided into three phases, Information Retrieval (IR), Information Extraction (IE) and Dictionary Construction (DC). We propose a query modification method using automatically constructed thesaurus for IR and a statistical keyword prediction method for IE. A dictionary of domain specific terms, which is one of the central knowledge sources for the task of knowledge acquisition, is also constructed automatically in the DC phase. IFBP is currently used for constructing the Transcription Factor DataBase (TFDB) and shows good performance. Since the model of knowledge base construction that is adopted into IFBP is carried out entirely automatically, this system can be easily ported across domains.

Algorithms↗
PubMed1997

Analysis of DNA from subjects found to be heterozygous for the haptoglobin-Johnson alpha gene.

We found two rare Hp Johnson variant families (Hp2-Johnson type and Hp1-Johnson type) by PAGE. It was confirmed by SDS-PAGE that the haptoglobin molecules with the Hp Johnson variant consisted of alpha-2 or alpha-1 and alpha-3 subunits. Direct gene analysis of Hp Johnson heterozygous individuals using three endonucleases: EcoRI, HindIII and BamHI, showed a three-fold tandem repeat of the same 1.7-kb DNA fragment implicated in the Hp alpha-2 gene duplication, and this Hp-Johnson-specific extension was identified in two generations of the Hp2-Johnson and Hp1-Johnson families.

DNA↗
PubMed1996

Genomic organization, expression, and chromosomal mapping of the mouse adrenomedullin gene.

We have isolated and characterized the mouse adrenomedullin (AM) gene (Adm) and determined its chromosomal location. The gene spans approximately 2.1 kb and is organized into four exons separated by three introns. The transcription start site was determined to be the adenine nucleotide at -618. The mouse AM 5'-flanking region contains a TATA box-like sequence and several cis-acting regulatory elements. Analysis of the nucleotide and deduced amino acid sequences revealed that mouse preproAM is a 184-amino-acid polypeptide, from which AM and proAM N-terminal 20 peptide are cleaved. Using restriction fragment length variants on a DNA panel of interspecific backcross mice, we mapped Adm to a distal region of mouse chromosome 7.

Adrenomedullin↗
PubMed1996

Molecular cloning of rat leptin receptor isoform complementary DNAs--identification of a missense mutation in Zucker fatty (fa/fa) rats.

We cloned the full-length rat leptin receptor (Ob-R) isoform complementary DNAs (cDNAs) and examined the gene expression in rats. We also identified a mutation in Ob-R in Zucker fatty (fa/fa) rats. Three alternatively spliced isoforms (Ob-Ra, Ob-Rb, and Ob-Re) have been identified, which are closely related to the gp130 signal-transduction component of class I cytokine receptors. Rat Ob-Ra and Ob-Rb were single transmembrane proteins, which differ in the C-terminal amino acid sequences. On the other hand, Ob-Re had no transmembrane domain and was a soluble form of the receptor. Reverse transcription-polymerase chain reaction analysis revealed that Ob-R isoform messenger RNAs (mRNAs) are expressed in a wide variety of rat tissues in tissue-specific manners. A missense mutation (an A to C conversion at nucleotide position 806) was found in the extracellular domain of all the isoforms in Zucker fatty (fa/fa) rats, which resulted in an amino acid change from Gln to Pro at + 269 (the Gln269Pro mutation). These Ob-R isoform mRNAs were present in the brain from Zucker fatty (fa/fa) rats at comparable amounts to those in their lean littermates. The present study provides new insight into the molecular mechanisms for Ob-R.

Alternative Splicing↗
PubMed1996

Determination of intermediates of hemoglobin-haptoglobin complex of haptoglobin polymers by "Crossed hemoglobin electrophoresis".

We designed a "crossed hemoglobin electrophoresis" to be able to detect the intermediates of a hemoglobin-haptoglobin complex without the need for the purification step of haptoglobin molecules. Native polyacrylamide gel electrophoresis was performed as the first dimensional electrophoresis followed by a cross to hemoglobin as the second dimensional electrophoresis. Using this method, we found that a number of intermediates of normal Hp 2-2, Hp 2-1 polymers, particularly those from the trimer to the pentamer, were detected on a polyacrylamide gel. Each of their polymers combined to the hexamer with at least an equimolar content of hemoglobin. In the process of detecting the haptoglobin serotype of more than 10,000 patients for the clinical utilization of quantitative analytical data, we observed two haptoglobin variants, the Hp Johnson and a haptoglobin serotype similar to the Carlberg type. Using our crossed hemoglobin electrophoresis, we also detected the capacity for combining with hemoglobin of each polymer of these variants.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1996

The interaction between Ku antigen and REF1 protein mediates negative gene regulation by extracellular calcium.

Through the specific binding of a negative calcium-responsive element to its binding protein in response to extracellular Ca (Ca2+e), negative calcium-responsive element-bearing genes, such as the human parathyroid hormone gene, are negatively regulated by Ca2+e. The Ku antigen mediated negative gene regulation by Ca2+e by interacting with a redox factor protein, REF1. Although sequence-nonspecific DNA binding activity of the Ku antigen has been well characterized, the mechanism of its sequence-specific DNA binding remained obscure. Here, we report that the specific binding of the Ku antigen to another protein, REF1, leads to DNA-protein complex formation with a novel sequence specificity and thereby regulates gene expression.

Amino Acid Sequence↗
PubMed1996

Cloning of rat GADD45 gene and induction analysis following ionizing radiation in vivo.

A gene encoded GADD45 was isolated from rat and revealed four exons along with a p53 binding consensus sequence and a putative AP-1 site in the third intron. This suggests that the rat GADD45 gene is also involved in the p53 signal pathway related to the G1 cell cycle checkpoint. The rat GADD45 mRNA was induced within 30 min in liver and increased as a function of gamma-irradiation. We found that mRNA expression differed substantially in a variety of tissues (brain, liver, kidney, and spleen). The finding of in vivo induction of GADD45 gene may provide insight into the role of GADD45 gene in DNA repair.

Alkylating Agents↗
PubMed1996

Comparative allelotype of early and advanced stage non-small cell lung carcinomas.

To identify chromosomal loci of tumor suppressor genes involved in the genesis and progression of non-small cell lung carcinoma (NSCLC), comparative allelotype analysis was performed in 23 stage I primary lung tumors and in 22 metastatic lung tumors to the brain. In total, 84 loci on all 22 autosomal chromosomes were examined for loss of heterozygosity (LOH) by restriction fragment length polymorphism (RFLP) analysis with 40 polymorphic DNA probes and polymerase chain reaction (PCR)-LOH analysis of 44 polymorphic loci. LOH on chromosome arms 3p, 13q, and 17p was detected frequently (> 60%) in both stage I primary lung tumors and brain metastases, whereas the incidence of LOH on chromosome arms 2q, 5q, 9p, 12q, 18q, and 22q was more than 60% only in brain metastases. In particular, the incidence of LOH on chromosome arms 2q, 9p, 18q, and 22q in brain metastases was significantly higher than that in stage I primary lung tumors (P < 0.05). These results indicate that tumor suppressor genes on chromosome arms 3p, 13q, and 17p are involved in the genesis of NSCLC, whereas those on several chromosome arms, especially on 2q, 9p, 18q and 22q, play an important role in the progression of NSCLC.

Brain Neoplasms↗
PubMed1996

Detection of amplified genomic sequences in human small-cell lung carcinoma cells by arbitrarily primed-PCR genomic fingerprinting.

The arbitrarily primed-PCR (AP-PCR) genomic fingerprinting method was applied to evaluate its effectiveness in detecting and characterizing amplified DNA fragments in two small-cell lung carcinoma (SCLC) cell lines, NCI-H69 and NCI-H82. Of the 2428 DNA fragments detected by AP-PCR using 62 arbitrary primers, 2 (0.08%) DNA fragments were amplified in NCI-H69 and 6 (0.25%) DNA fragments were amplified in NCI-H82. Based on these results, we estimate the total size of the amplified genomic regions in these cell lines to be 3000 megabase pairs (Mb) x 0.0008 = 2.4 Mb in NCI-H69 and 3000 Mb x 0.0025 = 7.5 Mb in NCI-H82. The 2 amplified fragments in NCI-H69 were mapped to chromosome 2, and all 6 amplified fragments in NCI-H82 were mapped to chromosome 8. This strongly suggests that restricted chromosomal regions are specifically amplified in these SCLC cell lines. Since the N-myc gene at 2p24 is amplified in NCI-H69 and the c-myc gene at 8q24 is amplified in NCI-H82, it is possible that these DNA fragments are co-amplified with N-myc or c-myc in these cell lines. However, since the 2 amplified fragments in NCI-H69 were not amplified in 42 other human cancer cell lines including 11 cell lines carrying amplified N-myc genes, it is also possible that there are amplified regions on chromosome 2 other than the N-myc locus at 2p24 in NCI-H69. In contrast, all 6 amplified fragments in NCI-H82 were amplified in several other human cancer cell lines carrying amplified c-myc genes. This result further indicates that these fragments were derived from an amplification unit that includes the c-myc gene. Our results show the ability of the AP-PCR method to analyze the fraction of the genome with amplification in human cancer cells.

Base Sequence↗
PubMed1996

Molecular cloning and nucleotide sequences of cDNA clones of sheep and goat adrenocortical cytochromes P450scc (CYP11A1).

We isolated cDNA clones of the mRNAs for cytochromes P450scc (CYP11A1) from sheep and goat adrenocortices using the RT-PCR method. We determined the complete nucleotide sequences of the coding and 3'-flanking regions of these cDNA clones. The results confirmed the amino terminal sequence of the sheep cytochrome P450scc reported previously [Miyatake et al., Biochim. Biophys. Acta 1215,176-182 (1994)]. On the basis of comparison of the deduced amino acid sequences of various animals and rainbow trout cytochromes P450scc, and other mitochondrial cytochrome P450 isozymes, we discussed the substrate-associated and adreno-ferredoxin-binding region of cytochrome P450scc.

Adrenal Cortex↗
PubMed1996

Lack of intestinal pacemaker (C-KIT-positive) cells in infantile hypertrophic pyloric stenosis.

The pathogenesis of infantile hypertrophic pyloric stenosis (IHPS) is not well understood. Recent studies have shown that the protonocogene c-kit is essential for the development or maintenance of autonomic gut motility, and also show that the c-kit gene protein product (C-KIT) positive cells in the mammalian gut are responsible for intestinal pacemaker activity. This study examines cells in the pyloric muscles of 23 patients (16 with IHPS, 7 controls) for the presence of the C-KIT (C-KIT+), using immunohistochemical techniques with antihuman C-KIT sera. In the controls, many C-KIT immunoreactive (IR+) cells were observed in the muscle layers. The myenteric plexuses were demarcated by a moderate number of C-KIT-IR+ cells. However, in the IHPS patients, C-KIT-IR were either absent or significantly reduced. No C-KIT-IR+ cells were found around the myenteric plexuses. These findings suggest that a lack of c-kit expression (as an indicator of intestinal pacemaker activity) in the hypertrophic pyloric smooth muscles may be an important factor in the pathogenesis of IHPS.

Biological Clocks↗
PubMed1996

Anti-neutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis: anti-cathepsin G and a novel antibody correlate with a refractory type.

We analysed the clinical significance of ANCA in patients with ulcerative colitis. On either an indirect immunofluorescence assay or an ELISA with fixed neutrophils, 71% (25/35) of the patients were positive for ANCA. However, only half of them reacted with either cathepsin G or lactoferrin. Western blot assays revealed positive bands in 40% (10/25) of the antibody-positive patients. The sizes of the bands detected were approximately 58, 47, 44, 40, and 28 kD. No significant correlation was found between the ANCA positivity and various variables, i.e. disease activity, extent of lesion, or treatment of the disease. The anti-cathepsin G and 28-kD positivity, however, significantly correlated with a refractory type of ulcerative colitis.

Adult↗
PubMed1996

A vascular smooth muscle-specific CD4+ T cell line that induces pulmonary vasculitis in MRL-+/+ mice.

We established a T cell line, MV1, specific for rat vascular smooth muscle antigen from the regional lymph nodes of immunized MRL/Mp-+/+ mice. Adoptive transfer of MV1 T cells induced vasculitis lesions in the lungs of the syngeneic recipient mice pre-treated with cyclophosphamide. Flow cytometric analysis showed that MV1 was a CD4+ T cell line. The T cells proliferated in the presence of the vascular smooth muscle antigen and mitomycin C-treated syngeneic spleen cells. The cross experiments using an ovalbumin-specific T cell line demonstrated that MV1 was specific for vascular smooth muscle antigen. The antigen-specific proliferation of MV1 was CD4-dependent, which was consistent with the flow cytometric analysis. In addition, MV1 T cells, upon activation with anti-CD3 antibody or antigen-specific activation, killed A20.2J mouse B lymphoma cells. MV1 T cells also killed a CD95 (Fas)-transfected T lymphoma line, but not its parental Fas-negative cell line. These findings indicate that MV1 T cells killed target cells via a Fas ligand (FasL)/Fas pathway. The cytotoxicity of MV1 T cells may play an important role in the development of vasculitis in this model. Although the antigenic epitopes of MV1 and the lung specificity of vasculitis remain to be clarified, MV1-induced vasculitis should serve as an experimental model of human pulmonary vasculitis.

Animals↗
PubMed1996

A novel DnaA protein-binding site at 94.7 min on the Escherichia coli chromosome.

There is a DNA sequence which has unusually high affinity for the DnaA protein of Escherichia coli between the glyV and amiB-mutL operons at 94.7 min on the genetic map. Affinity of DnaA protein for DNA was measured in vivo as the activity of beta-galactosidase produced from the lacZ gene on a plasmid fused to the 5'-terminal portion of the mioC gene, which is under the control of the DnaA protein. The chromosomal DNA segment between the two operons, carried on a compatible plasmid, derepressed the beta-galactosidase activity by titrating DnaA protein. Derepression occurred on the chromosomal dnaA gene as well, since it is autoregulated. Hence, as measured by immunoassays, one plasmid molecule carrying the DnaA-binding region titrated 370 dnaA molecules, which is a value eightfold higher than that for a plasmid containing the oriC region. We estimate that about 60% of the total cellular DnaA molecules are bound to this site. Four DnaA-binding sequences (DnaA boxes) and a DnaA-regulated promoter directing transcription of two small genes were present within a 250 bp stretch in this region but additional long DNA regions, including the fifth DnaA box located about 650 bp downstream, were required for maximum binding. A role for the DnaA-binding site in controlling DnaA-protein concentration in the cell cycle is discussed.

Bacterial Proteins↗