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Biomedical subjects

M Morita

Publications and source records attributed to M Morita.

At least 163 records · Page 9Linked to original sources

Regulation of lens fiber cell differentiation by transcription factor c-Maf.

To elucidate the regulatory mechanisms underlying lens development, we searched for members of the large Maf family, which are expressed in the mouse lens, and found three, c-Maf, MafB, and Nrl. Of these, the earliest factor expressed in the lens was c-Maf. The expression of c-Maf was most prominent in lens fiber cells and persisted throughout lens development. To examine the functional contribution of c-Maf to lens development, we isolated genomic clones encompassing the murine c-maf gene and carried out its targeted disruption. Insertion of the beta-galactosidase (lacZ) gene into the c-maf locus allowed visualization of c-Maf accumulation in heterozygous mutant mice by staining for LacZ activity. Homozygous mutant embryos and newborns lacked normal lenses. Histological examination of these mice revealed defective differentiation of lens fiber cells. The expression of crystallin genes was severely impaired in the c-maf-null mutant mouse lens. These results demonstrate that c-Maf is an indispensable regulator of lens differentiation during murine development.

Animals↗

A new mechanism of acquisition of drug resistance by partial duplication of topoisomerase I.

Topoisomerase (topo)-I targeting antitumor agents are very effective in vivo against various human cancers. The indolocarbazole compound 6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl)- 5H-indolo[2,3-alpha]pyrrolo-[3,4-c]carbazole-5,7(6H)-dione (NB-506) is a potent inhibitor of the religation step of topo I reaction, like camptothecin (CPT). We established a NB-506-resistant cell line from murine leukemia cell line P388. This resistant cell line, P388/F11, exhibited 73-fold higher resistance to NB-506 and 3.5-fold higher cross-resistance to CPT than the parental cell line. No induction of cleavable complex formations induced by NB-506 and CPT were detected by K-SDS precipitation assays in P388/F11 cells. Analysis of nuclear extracts from P388/F11 cells revealed that the relaxation activity of topo I was one-quarter of that of the parental cells, and that the activity was resistant to induction of DNA cleavage by these drugs. Furthermore, Western blot and Northern blot analyses showed the expression of an abnormal-sized 170-kDa topo I protein and its 6.0-kb transcript and the absence of the normal topo I protein and transcript in P388/F11 cells. Analyses of the structure of the abnormal topo I transcript by reverse transcription-PCR and direct sequencing methods revealed that a large portion of the gene from codon 21 to codon 609 was duplicated in its coding region. This internal duplication resulted in in-frame fusion and, thus, production of a partially duplicated protein of 1357 amino acids. Finally, we expressed and purified the recombinant P388/F11 topo I in a baculovirus system. P388/F11 topo I showed similar catalytic activity to wild-type topo I, but reduced sensitivities to NB-506 and CPT. These results show that the altered sensitivity of duplicated topo I is involved in the NB-506 resistance of P388/F11 cells and indicate a novel resistant mechanism which involves duplication of the topo I gene.

Animals↗

Paraquat myopathy: report on two suicide cases.

We describe two suicide cases in which old paraquat was ingested. In conjunction with lung involvement a pronounced degeneration was observed in skeletal muscle of one who died on the 14th day after the ingestion. The following sarcoplasmic or endoplasmic reticulum Ca2+ ATPase (SERCA) monoclonal antibodies were used for skeletal muscle fiber typing by an immunohistochemical method: NCL-SERCA1, reactive with type 2 fiber (fast-twitch), and NCL-SERCA2, reactive with type 1 fiber (slow-twitch). The examination revealed that the remarkably degenerated fibers belonged to type 1 muscle fibers. This case showed an abrupt increase of plasma CK levels (1796 mU/ml) on the fifth day after the ingestion. The authors presume that the damage to the skeletal muscle had occurred in this period. The degeneration of the muscle seemed to be attributable to the long retention of paraquat in the tissue because these findings were not observed in the other case who died on the fifth day. Paraquat-induced myopathy may develop in prolonged paraquat poisoning. The examination of CK levels in plasma will be useful for diagnosis of damage of skeletal muscle.

Aged↗

Effects of 3alpha- and 3beta-galactosylated alpha-galactosylceramides on the immune system.

We compared effects of alpha-galactosylceramide (alpha-GalCer) and its 3alpha- or 3beta-galactosylated derivatives on the proliferation of murine spleen cells. The 3alpha-galactosylated alpha-GalCer showed stronger proliferative response than the parental alpha-GalCer, but the 3beta-galactosylated alpha-GalCer possessed weaker activity than the alpha-GalCer. In addition, alpha-Gal-3-Cer did not show immunostimulatory activity.

Adjuvants, Immunologic↗

Isolation and characterization of new limonoid glycosides from Citrus unshiu peels.

Three limonoid glycosides were isolated from Citrus unshiu peels, and their structures were determined based on MS and NMR spectroscopic data as nomilinic acid 17-O-beta-D-glucopyranoside (1), methyl nomilinate 17-O-beta-D-glucopyranoside (2), and obacunone 17-O-beta-D-glucopyranoside (3). In particular, the location of the sugar moiety was clearly determined by the B/E constant linked scan FABMS method. No limonoid glycosides obtained here were found to have antitumor activity in NCI-H292 and EL-4 cell lines.

Animals↗

CMAP: a novel cystatin-like gene involved in liver metastasis.

A novel metastasis-associated gene was identified with a differential display system in murine carcinoma cells showing a high rate of metastasis to the liver. A human homologue was also identified using a PCR-based strategy. The protein coded by this gene was named cystatin-like metastasis-associated protein (CMAP) and showed 22.1-28.1% homology to human family 2 cystatins. CMAP mRNA was selectively overexpressed in all murine liver metastatic tumors but not in any pulmonary metastatic tumors examined. Transfection of CMAP antisense DNA into highly metastatic liver cells greatly decreased their metastatic potential and CMAP expression, indicating that CMAP is involved in liver metastatic ability after intravasation of malignant cells. The human homologue of CMAP was found to be expressed in various human cancer cell lines established from malignant tumors. Our discovery of this novel liver metastasis-related gene indicates a new approach to the diagnosis and/or prevention of liver metastasis of human cancer.

Amino Acid Sequence↗

Esophageal carcinoma showing a long stricture due to prominent lymphatic permeation: report of a case.

Some esophageal diseases such as carcinoma, esophagitis, and collagen diseases have often been reported to show a diffusely thickened esophageal wall in the roentogenogram findings. In the current report, a preoperative upper gastrointestinal series and an endoscopic examination showed a diffusely infiltrative type carcinoma, but other examinations did not suggest any diseases such as esophagitis or collagen diseases which might cause a thickening of the esophageal wall or a constriction of the esophagus. A postoperative histological examination revealed the primary carcinoma to remain only within the mucosal layer, while a large degree of lymphatic vessel permeation reached the adventitia over a wide area. An extraordinary degree of lymphatic permeation spread through the esophageal wall, and stromal fibrosis developed as a result of such lymphatic permeation. These histological phenomena might thus have led to the macroscopic appearance of infiltrative type esophageal carcinoma.

Carcinoma, Squamous Cell↗

Generation of new transposons in vivo: an evolutionary role for the "staggered" head-to-head dimer and one-ended transposition.

From a plasmid carrying the tnpA gene and one inverted repeat sequence (IR) of transposon Tn3, plasmids containing a structure characteristic of transposons, i.e., two IRs flanking a tnpA gene, were generated spontaneously in vivo. They appear to have arisen either through the formation of a "staggered" head-to-head dimer or by so-called one-ended transposition. These putative transposons could indeed transpose to, or form cointegrates with, a recipient plasmid. Based on these findings it is proposed that a primeval transposase gene and its target site evolved first, and subsequently gave rise to a "fully-fledged" transposon by head-to-head dimerization or one-ended transposition.

Base Sequence↗

Levels of chondroitin sulfate isomers in synovial fluid of patients with hip osteoarthritis.

We determined the levels of chondroitin sulfate (CS) isomers in the synovial fluid of patients with hip osteoarthritis (OA) to investigate their significance as markers reflecting extracellular matrix metabolism in joint tissues. A cross-sectional study of synovial fluid aspirated from 50 hip joints of 50 patients with OA was performed. Concentrations of chondroitin-4-sulfate (C4S) and chondroitin-6-sulfate (C6S) were determined by high-performance liquid chromatography. Levels of each marker molecule were investigated in relation to age and radiological stage of the disease. In all disease stages, the dominant CS isomer in synovial fluid was C6S. There was a significant negative correlation between levels of C6S and age. A significant inverse correlation was also observed between the ratio of C6S to C4S and age. Results of analysis of covariance in which age was covariate showed that the ratio of C6S to C4S in advanced and terminal stage OA was lower than that in early stage OA. The present results indicate that the ratio of CS isomers in synovial fluid in hip OA varies with the severity of disease. These molecules in synovial fluid may serve as a useful marker reflecting extracellular matrix metabolism in OA.

Adult↗

Results of laparoscopic splenectomy for immune thrombocytopenic purpura.

BACKGROUND: Laparoscopic splenectomy has been demonstrated to be technically feasible and safe for the treatment of immune thrombocytopenic purpura (ITP), hereditary spherocytosis, and Hodgkin's disease. PATIENTS AND METHODS: The study comprised 76 consecutive patients with chronic ITP who were admitted to our hospital from 1968 to 1997 and underwent splenectomy; 35 patients underwent a laparoscopic splenectomy, and 41 had open surgery. RESULTS: Laparoscopic splenectomy involved minimal incision, and a significantly lower frequency of analgesia was required for postoperative abdominal pain (1.4 versus 3.3); postoperative hospital stay was shorter (9.6 versus 20.1 days, P <0.05). Operative time was significantly longer for the laparoscopic surgery (204.5 versus 99.8 minutes, P <0.01), but blood loss was less (154.4 versus 511.7 g, P <0.01). During the present study (range 3.8 to 80 months), accumulative nonrecurrence rate was 67.9% in 5 years after surgery, which is similar to that of the previous open splenectomy. CONCLUSIONS: Laparoscopic splenectomy can become an alternative therapeutic modality in the treatment of ITP.

Adult↗

PCDDs and PCDFs in vehicle exhaust particles in Japan.

Vehicle exhaust particles from gasoline and diesel engine cars were analyzed for PCDDs and PCDFs. The congener patterns of PCDDs and PCDFs in exhaust particles were different between gasoline and diesel engine cars. Suspended particulate matter from electrostatic precipitator connected to a highway tunnel was also analyzed for PCDDs and PCDFs. The congener pattern of suspended particular matter was different from both of gasoline and diesel engine cars. Total amounts of PCDDs/PCDFs sum concentrations in gasoline, diesel and suspended particulate matter were 0.21, 0.87 and 26.0 ng/g, respectively. The I-TEQs levels in gasoline, diesel and suspended particulate matter were 4.2, 11 and 242 pg/g, respectively.

Air Pollutants↗

Identification and cloning of a novel isoform of mouse secretory leukocyte protease inhibitor, mSLPI-beta, overexpressed in murine leukemias and a highly liver metastatic tumor, IMC-HA1 cells.

Several genes showing transcriptional alteration in a highly liver metastatic murine carcinoma cell line, IMC-HA1, were identified by mRNA differential display system. Among them, a gene identical to mSLPI was isolated as mSLPI-alpha and -beta. They were produced through an alternative splicing. Their full-length cDNA sequences were determined, and their expression in various murine tumors and normal tissues was analysed. The deduced translation product of mSLPI-alpha showed 59% identity to hSLPI. Although mSLPI-beta had the same 103-amino-acid sequence from the carboxyl terminus, the amino terminus showed hydrophilicity opposite mSLPI-alpha or hSLPI. The mSLPI-alpha was expressed ubiquitously in various tumor cell lines. Interestingly, however, mSLPI-beta expression was only observed in P388 and L1210 leukemias and IMC-HA1 cells, and in lower amounts in three normal tissues (thymus, lung and spleen), suggesting that mSLPI, and in particular the unusual splicing product, mSLPI-beta, plays a specific role in these cells, including malignant processes of tumor cells.

Amino Acid Sequence↗

Structural analyses of a precursory substance of bitterness: new polyisoprenepolyols isolated from an edible mushroom (Hypsizigusmarmoreus) by fast atom bombardment mass spectrometry.

New polyisoprenepolyols (hypsiziprenol AA and BA) were isolated from an edible mushroom (Hypsizigus marmoreus). These polyols occur as a mixture of homologous polyisoprene derivatives with 40-70 carbon atoms. Analyses by FAB/MS in the positive and negative ion modes are complementary with each other in that the former provides information on the number of hydroxy groups present while the latter specifies the isoprenoid sequence, and thus become a powerful tool for analyzing the structures of polyisoprenepolyols. No polyisoprenepolyols obtained here were found to have antitumor activity on NCI-H292 and EL-4 cell lines.

Agaricales↗

Serum antibodies to Mycobacterium paratuberculosis in patients with Crohn's disease.

Mycobacterium paratuberculosis has been suggested as a causative organism of Crohn's disease. Despite a long-term debate to prove this possibility, the role of this bacteria in the pathogenesis of Crohn's disease is still a subject of controversy. In the present study, serum antibodies (IgG, IgA, and IgM) to the protoplasmic antigen of M. paratuberculosis were quantified in patients with Crohn's disease and in control subjects by using an enzyme-linked immunosorbent assay whose specificity was increased by preabsorbing the sera with cell extracts of Mycobacterium phlei. As compared to normal controls (1/20; 0.062+/-0.022), a significant difference was seen in the antibody-positive prevalence rate and mean values of the serum IgG titer in patients with Crohn's disease (5/13; 0.102+/-0.039) (P < 0.05), but not in patients with ulcerative colitis (2/20; 0.065+/-0.035) and tuberculosis (0/4; 0.053+/-0.008). No significant differences were seen in the antibody-positive prevalence rate and mean values of the serum IgA and IgM titers among the four study groups. These results indicate the unique immune response to M. paratuberculosis in patients with Crohn's disease, suggesting that this organism may play some role in the pathogenesis of Crohn's disease.

Adolescent↗

Characterization of Epstein-Barr virus (EBV)-infected natural killer (NK) cell proliferation in patients with severe mosquito allergy; establishment of an IL-2-dependent NK-like cell line.

The clinical evidence of a relationship between severe hypersensitivity to mosquito bite (HMB) and clonal expansion of EBV-infected NK cells has been accumulated. In order to clarify the mechanism of EBV-induced NK cell proliferation and its relationship with high incidence of leukaemias or lymphomas in HMB patients, we studied clonally expanded NK cells from three HMB patients and succeeded in establishing an EBV-infected NK-like cell line designated KAI3. Immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses revealed that KAI3 cells as well as infected NK cells exhibited an EBV latent infection type II, where EBV gene expression was limited to EBNA 1 and LMP1. As KAI3 was established by culture with IL-2, IL-2 responsiveness of peripheral blood NK cells from patients was examined. The results represented markedly augmented IL-2-induced IL-2R alpha expression in NK cells. This characteristic property may contribute to the persistent expansion of infected NK cells. However, KAI3 cells as well as the NK cells from patients were not protected from apoptosis induced by either an anti-Fas antibody or NK-sensitive K562 cells. Preserved sensitivity to apoptosis might explain the relatively regulated NK cell numbers in the peripheral blood of the patients. To our knowledge, KAI3 is the first reported NK-like cell line established from patients of severe chronic active EBV infection (SCAEBV) before the onset of leukaemias or lymphomas. KAI3 cells will contribute to the study of EBV persistency in the NK cell environment and its relationship with high incidence of leukaemias or lymphomas in HMB patients.

Adolescent↗

Comparison of biting forces in different age and sex groups: a study of biting efficiency with mobile and non-mobile teeth.

This study aimed (1) to investigate the influences of sex, age and number of teeth on biting ability through a descriptive survey, and (2) to compare the biting ability between the subjects with and without mobile teeth in a case-control study. A total of 687 subjects cooperated in the descriptive survey. Each subject bit on a pressure detecting sheet with their maximum biting force. Three indices of biting ability: biting pressure (MPa), biting force (N) and occlusal contact area (mm2) were calculated from the impressed marks on the sheet using a high vision video processor system. These indices were correlated well with the number of teeth according to the multiple regression analysis. In the case-control study, matching procedures with sex, age and number of teeth were performed between the subjects with and without mobile teeth. No differences in the three indices were observed between the two well-balanced groups. The results showed that the number of teeth is most important to maintain biting ability, and that the presence of mobile teeth does not always reduce biting ability.

Adolescent↗