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Biomedical subjects

M Obara

Publications and source records attributed to M Obara.

At least 19 recordsLinked to original sources
PubMed2006

Assessment of efficacy of a live oral poliovirus vaccine for virulent Sabin-like poliovirus 1 strains in Japan.

Virulent Sabin-like poliovirus (VSLP) was isolated from river and sewage waters between October 1993 and September 1995 in Toyama Prefecture, Japan (Yoshida et al., Lancet 356, 1461-1463, 2000). In this study, to assess the possibility of an epidemic of poliomyelitis caused by a VSLP in Japan under the current vaccination policy of administration of live attenuated oral poliovirus vaccine (OPV), we determined titers of serum neutralizing antibodies to poliovirus 1 (PV-1) strains Sabin (vaccine strain), Mahoney (wild-type strain) and G4-12 (VSLP) in various groups of residents of Toyama Prefecture, Japan. The seropositivity and geometric mean neutralizing antibody titers against these strains in the individuals who obtained two doses of OPV were 99.1%, 94.5% and 95.5%, respectively, and 564, 186 and 194, respectively. Although the antibody titers to G4-12 were lower compared with those to Sabin, these results indicate that the OPV vaccination policy in Japan has been effective in preventing poliomyelitis caused by VSLPs. These results also suggest that (i) an epidemic of poliomyelitis caused by a VSLP has not occurred in Japan due to herd immunity, and (ii) the possibility of reemergence of VSLPs will be prevented if sufficient herd immunity is acquired immediately after completion of the OPV vaccination in accordance with the poliomyelitis eradication program.

Adolescent↗
PubMed2005

Effective in vivo purging with rituximab and autologous peripheral blood stem cell transplantation in a woman with CD5 positive primary cutaneous diffuse large B-cell lymphoma.

Generalized subcutaneous tumors developed without any other sites of the disease in a Japanese woman. Skin biopsy revealed CD5(+) and CD20(+) atypical diffuse large cells infiltrating subcutaneous tissues. The diagnosis was CD5(+) primary cutaneous diffuse large B-cell lymphoma. Tumor-specific PCR showed the existence of malignant cells in the peripheral blood and bone marrow. After three cycles of chemotherapy, she was remained in partial remission. Peripheral blood stem cells (PBSC) were harvested after the fourth cycles of chemotherapy combined with rituximab for in vivo purging. The contamination of tumor cells in PBSC was negative with PCR. She then underwent autologous peripheral blood stem cell transplantation using purged PBSC and has remained in complete remission for the past 24 month.

Antibodies, Monoclonal↗
PubMed2004

Localized relapse in bone marrow of extremities after allogeneic stem cell transplantation for acute lymphoblastic leukemia.

We report a patient with a relapsed in bone marrow of extremities after allogeneic peripheral blood stem cell transplantation for acute lymphoblastic leukemia (ALL). The patient complained of pain in the right upper arm and left leg 15 months after transplantation. Magnetic resonance imaging (MRI) and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) showed abnormal findings in bone marrow of upper and lower extremities. There were no findings of relapse in aspirates from the sternum and iliac bone marrow. Biopsy specimen from the iliac bone marrow showed normocellular marrow without leukemic cells. Biopsy specimen from the right humerus revealed marked leukemic cell infiltration in the bone marrow. This is apparently the first case of localized relapse of ALL in bone marrow of extremities. Physicians should be aware of unusual relapse sites of leukemia after allogeneic stem cell transplantation. MRI and FDG-PET may be of value in detecting this type of relapse.

Adult↗
PubMed2004

Peripheral blood stem cell mobilization following CHOP plus rituximab therapy combined with G-CSF in patients with B-cell non-Hodgkin's lymphoma.

We mobilized peripheral blood stem cells (PBSC) following CHOP plus rituximab (CHOP-R) therapy, and compared with the findings following CHOP therapy without rituximab. All patients were given G-CSF starting from day 11 after CHOP therapy. Patients in the CHOP-R group (n=8) were given rituximab on day 12. Target CD34(+) cells number was collected in a single leukapheresis on day 14, from all the eight patients in the CHOP-R group. PBSC mobilization kinetics, CD34(+) cells yield and colony-forming ability in the graft collection, toxicity during mobilization, and engraftment after transplantation of CHOP-R group were not significantly different from those in the CHOP group (n=8). In all patients given CHOP-R therapy, CD20(+) cells and immunoglobulin heavy chain (IgH) rearrangement in the graft collection were undetectable by flow-cytometric analysis and Southern blot analysis, respectively, but with PCR analysis two of eight grafts were positive for IgH rearrangement. While further studies are needed to evaluate the efficacy of purging and the outcome of patients undergoing autologous transplantation, CHOP-R therapy can be safely and effectively used in the mobilization phase of PBSC collection, without excess clinical toxicity or deleterious effect on PBSC mobilization kinetics or engraftment time.

Adult↗
PubMed2003

Successful treatment with rituximab for autoimmune hemolytic anemia concomitant with proliferation of Epstein-Barr virus and monoclonal gammopathy in a post-nonmyeloablative stem cell transplant patient.

A 30-year-old Japanese woman who underwent nonmyeloablative stem cell transplantation from her HLA-matched sister developed autoimmune hemolytic anemia (AIHA). There was proliferation of EBV-DNA in her peripheral blood and monoclonal gammopathy, both predictive factors of post-transplant lymphoproliferative disorder (PTLD). As conventional immunosuppressive therapy for AIHA could lead to overt PTLD, we decided to give her rituximab 375 mg/m(2) once weekly for a total of four doses. After this therapy, both her AIHA and monoclonal gammopathy were resolved and EBV-DNA became undetectable. Rituximab therapy deserves consideration for treatment of post-allogeneic stem cell transplant patients with AIHA, especially for patients who cannot be given immunosuppressive therapy.

Adult↗
PubMed2002

Expression of pleiotrophin in hepatic nonparenchymal cells and preneoplastic nodules in carbon tetrachloride-induced fibrotic rat liver.

Pleiotrophin (PTN) is a heparin-binding protein, which induces growth, angiogenesis, differentiation, and transformation of cells. The aim of this study was to examine the role of PTN in liver fibrogenesis. Rats were treated with carbon tetrachloride (CCl4) for 3-9 weeks to induce liver fibrosis. The sirius-red staining of these liver tissue sections clearly showed the development of fibrosis and glutathione S-transferase placental type-positive preneoplastic nodules emerged at 7 weeks of the treatment. PTN expression was investigated in fibrotic liver tissues at the mRNA level using a real-time reverse transcription polymerase chain reaction and at the protein level by immunohistochemistry. Quantity of PTN mRNA increased 5-fold in fibrotic liver tissues at 7 weeks of CCl4-treatment over the control values. Immunohistochemistry localized PTN protein on hepatic nonparenchymal cells, mostly stellate cells and some of Kupffer cells, and the preneoplastic nodules in fibrotic liver tissues. PTN mRNA expression is significantly upregulated in the CCl4-induced chronic rat fibrotic liver tissues. We suggest that PTN might be involved in fibrogenesis and preneoplastic changes of liver.

Animals↗
PubMed2001

Nanosecond, high-intensity pulsed laser ablation of myocardium tissue at the ultraviolet, visible, and near-infrared wavelengths: in-vitro study.

BACKGROUND AND OBJECTIVE: A large number of clinical trials of transmyocardial laser revascularization (TMLR) have been conducted to treat severe ischemic heart diseases. A variety of laser sources have been used or tested for this treatment, however, no comprehensive study has been performed to reveal the mechanism and the optimum laser irradiation condition for the myocardium tissue ablation. There have been reported limited experimental data of the high-intensity pulsed laser ablation of myocardium tissues. STUDY DESIGN/MATERIALS AND METHODS: A 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonics were used for ablation experiments. At each wavelength, 25 laser pulses irradiated the porcine myocardium tissue samples at a constant laser intensity (peak laser power divided by laser spot area) of approximately 2 GW/cm(2) and the ablation depths were measured. During ablation, laser-induced optical and acoustic emissions were measured to investigate the ablation mechanism at each laser wavelength. For the ablated tissues, histological observation was made with a polarization optical microscope. RESULTS: It was shown that the ablation efficiency did not directly depend on the linear absorption coefficient of the tissue; the ablation depth was maximized at 355 and 1064 nm, and minimized at 532 nm. Strong laser-induced optical and acoustic emissions were observed for the 266- and 1064-nm laser irradiations. The histology showed that thermal denaturation of the tissue near the ablation walls decreased with decreasing wavelength for 266, 355, and 532 nm, but it was limited for 1064 nm. CONCLUSION: At the laser intensity of approximately 2 GW/cm(2), ablation characteristics were drastically changed for the different laser wavelengths. The results indicated that for 266, 355, and 532 nm, the tissue removal was achieved mainly through a photothermal process, but for 266 nm the intense laser-induced plasma formation would result in a reduced laser energy coupling to the tissue. For 1064 nm, a photodisruption was most probable as a dominant tissue removal process. Because of the high ablation rate and limited thermal denaturation, the 355- and 1064-nm lasers could be potential laser sources for TMLR, although further investigation is needed to discuss the clinical issues.

Angioplasty, Laser↗
PubMed2001

Effect of reactive oxygen species on fetal lung maturation.

OBJECTIVES: Fetal lung maturation in preterm infants with chorioamnionitis is known to be accelerated. However, the molecular basis of this pathological acceleration has not been elucidated. We investigated whether reactive oxygen species play a role in the acceleration of fetal lung maturation. STUDY DESIGN: On the 16th day of gestation, xanthine (1mM) and xanthine oxidase solution (0.1-100mU/ml) were injected into the intrauterine cavity of pregnant rats. On the 19th day of gestation, we examined the expression of the mRNA of surfactant associated proteins A, B and C (sp-A, sp-B and sp-C) by reverse transcription-polymerase chain reaction. RESULTS: sp-A, sp-B and sp-C mRNAs were observed in lung tissue from fetal rats stimulated by xanthine-xanthine oxidase in contrast to the control. CONCLUSION: Reactive oxygen species in amniotic fluid might be an important factor in accelerated fetal lung maturation associated with chorioamnionitis in the rat experimental model.

Animals↗
PubMed2001

Membrane-type 1 matrix metalloproteinase is induced in decidual stroma without direct invasion by trophoblasts.

Membrane-type 1 matrix metalloproteinase (MT1-MMP) in endometrium and decidua may greatly affect attachment of the embryo to the epithelium, invasion of the trophoblast into the stroma, and extracellular matrix remodelling in the endometrium and decidua. We investigated the expression of this enzyme in normally cycling endometrium and in decidua associated with normal and tubal pregnancies at both the gene and protein level. Localization of expression (but not the overall level of expression), differed between endometrium and decidua parietalis and tubal pregnancy decidua. MT1-MMP mRNA was expressed mainly in epithelium and only faintly in stroma throughout the menstrual cycle, while in decidua parietalis and tubal pregnancy decidua, this mRNA was expressed predominantly in stromal cells. MT1-MMP protein was detected in the epithelium alone throughout the menstrual cycle, while in decidua parietalis and tubal pregnancy decidua, it was detected in stromal cells as well as the epithelium. Since decidua showed altered expression in the absence of trophoblastic contact, trophoblast invasion may not directly affect MT1-MMP gene expression.

Adult↗
PubMed2001

Temperature measurement for energy-efficient ablation by thermal radiation with a microsecond time constant from the corneal surface during ArF excimer laser ablation.

Measurement of the temperature of the corneal surface during photorefractive keratectomy (PRK) is thought to be useful for monitoring the corneal ablation process, since the photothermal process has been proposed as the major mechanism of ArF excimer laser ablation. For temperature measurement, we measured thermal radiation from the corneal surface during ArF excimer laser ablation using a mercury-cadmium-telluride detector with a 1-micros time constant. To investigate the effects of temperature on ablation depth, the ablation depth of the cornea was measured by microscopy. When corneal ablation was initiated at the fluence of 65 mJ/cm2, the corneal surface temperature rose to 60-70 degrees C. The energy required for a unit-depth ablation (degrees C/microm) was lowest at 120 micro C. Monitoring of transient temperature during PRK provides important information on energy-efficient ablation, which may enable rapid and safe corneal incisions.

Animals↗
PubMed2001

Changes in molecular weight of hyaluronan and hyaluronidase activity in uterine cervical mucus in cervical ripening.

BACKGROUND: This study was undertaken to investigate changes in the forms of hyaluronan and hyaluronidase activity in cervical mucus during cervical ripening. METHODS: Uterine cervical mucus was obtained from 57 pregnant women (25 at preterm gestation, ten at term gestation, 11 within 1 week before labor, and 11 during the first stage of labor). We determined 1) concentration of hyaluronan, 2) hyaluronidase activity, and 3) molecular weight of hyaluronan in cervical mucus. Data are presented as mean and range. RESULTS: The hyaluronan concentration in mucus in the 1st stage of labor (1.58 microg/ml, 0.46-23.96) was significantly (p<0.05) higher than that in all other groups (preterm: 0.29, 0.10-0.88; term: 0.24, 0.11-0.80; within 1 week before labor: 0.30, 0.18-0.62). Hyaluronidase activity both within 1 week before labor group (3.03 min., 1.12-3.95) and in 1st stage of labor group (3.52, 0.43-5.15) was significantly (p<0.05) higher than that in preterm group (1.70, 0.00-5.47). The molecular weight of hyaluronan in cervical mucus in the 1st stage of labor (0.97x106, 0.86-1.41) was significantly (p<0.05) lower than in the preterm and term groups (preterm: 1.60, 1.21-2.20, term: 1.41, 1.21-2.20). There was a significant correlation between hyaluronidase activity and molecular weight of hyaluronan (p<0.05, r=-0.41, n=23). CONCLUSION: These findings suggest that either hyaluronidase or low-molecular weight hyaluronan could be one of the most important regulators in the process of cervical ripening.

Analysis of Variance↗
PubMed2001

Mapping of QTLs associated with cytosolic glutamine synthetase and NADH-glutamate synthase in rice (Oryza sativa L.).

Ninety-eight backcross inbred lines (BC1F6) developed between Nipponbare, a japonica rice, and Kasalath, an indica rice were employed to detect putative quantitative trait loci (QTLs) associated with the contents of cytosolic glutamine synthetase (GS1; EC 6.3.1.2) and NADH-glutamate synthase (NADH-GOGAT; EC 1.4.1.14) in leaves. Immunoblotting analyses showed transgressive segregations toward lower or greater contents of these enzyme proteins in these backcross inbred lines. Seven chromosomal QTL regions for GS1 protein content and six for NADH-GOGAT protein content were detected. Some of these QTLs were located in QTL regions for various biochemical and physiological traits affected by nitrogen recycling. These findings suggested that the variation in GS1 and NADH-GOGAT protein contents in this population is related to the changes in the rate of nitrogen recycling from senescing organs to developing organs, leading to changes in these physiological traits. Furthermore, a structural gene for GS1 was mapped between two RFLP markers, C560 and C1408, on chromosome 2 and co-located in the QTL region for one-spikelet weight. A QTL region for NADH-GOGAT protein content was detected at the position mapped for the NADH-GOGAT structural gene on chromosome 1. A QTL region for soluble protein content in developing leaves was also detected in this region. Although fine mapping is required to identify individual genes in the future, QTL analysis could be a useful post-genomic tool to study the gene functions for regulation of nitrogen recycling in rice.

Biological Transport↗
PubMed2000

Kdap, a novel gene associated with the stratification of the epithelium.

The skin develops and differentiates during embryogenesis, which is concertedly regulated by a variety of genes. The present study isolated from the rat embryonic skin a novel differentiation-associated gene named Kdap (keratinocyte differentiation-associated protein) by suppression subtractive hybridization between the skin of 14day postcoitus (dpc) embryo (the prehair-germ stage) and that of 17dpc embryo (the hair-germ stage). Its mRNA contained four spliced forms in these tissues. The gene encoded a protein of total 98 amino acids with a calculated molecular mass of 11kDa and an isoelectric point of 6.1 as an unspliced form. The two splicing zones were well conserved among rat, mouse, and human. This protein had a high hydrophobic N-terminal region, a possible signal sequence, and contained two putative N-myristoylation sites and two casein kinase II phosphorylation sites. In situ hybridization experiments detected Kdap transcripts exclusively in the suprabasal cell layers of the embryonic epidermis. Intense expression was also seen in suprabasal cells in regions of infundibulum of the hair follicle. These results indicated that Kdap provides a new insight into the mechanism of differentiation and the maintenance of stratified epithelia.

Amino Acid Sequence↗
PubMed2000

Does chondroitin sulfate defend the human uterine cervix against ripening in threatened premature labor?

OBJECTIVE: This study was undertaken to investigate changes in chondroitin sulfate levels in the cervix and the physiologic role of chondroitin sulfate isomers in the process of cervical ripening. STUDY DESIGN: Uterine cervical mucus samples were obtained from 57 women (7 nonpregnant women, 19 at preterm gestation, 9 at term gestation, 16 during the first stage of term labor, and 6 with threatened premature labor). Chondroitin sulfate isomer (chondroitin 0-sulfate, 4-sulfate, and 6-sulfate) concentrations in cervical mucus were measured by high-performance liquid chromatography. The effect of exogenous chondroitin sulfate on hyaluronidase activity in cervical mucus was evaluated by gel permeation chromatography of fluorolabeled hyaluronic acid. RESULTS: Chondroitin sulfate concentrations in cervical mucus were increased significantly (P <. 05) in the threatened premature labor group compared with the preterm and term groups. However, the same finding was not observed in the first stage of term labor. Exogenous chondroitin sulfate inhibited hyaluronidase activity in mucus. CONCLUSION: Chondroitin sulfate may defend against cervical ripening in threatened premature labor.

Cervical Ripening↗
PubMed2000

Developmentally and regionally regulated participation of epidermal cells in the formation of collagen lamella of anuran tadpole skin.

We investigated the cellular mechanism of formation of subepidermal thick bundles of collagen (collagen lamella) during larval development of the bullfrog, Rana catesbeiana, using cDNA of alpha1(I) collagen as a probe. The originally bilayered larval epidermis contains basal skein cells and apical cells, and the collagen lamella is directly attached to the basement membrane. The basal skein cells above the collagen lamella and fibroblasts beneath it intensively expressed the alpha1(I) gene. As the skin developed, suprabasal skein cells ceased expression of the gene. Concomitantly, the fibroblasts started to outwardly migrate, penetrated into the lamella and formed connective tissue between the epidermis and the lamella. These fibroblasts intensively expressed the gene. As the connective tissue developed, the basal skein cells ceased to express the gene and were replaced by larval basal cells that did not express the gene. These dynamic changes took place first in a lateral region of the body skin and proceeded to all other regions except the tail. Isolated cultured skein cells expressed the gene and extracellularly deposited its protein as the type I collagen fibrils. Thus, it is concluded that anuran larval epidermal cells can autonomously and intrinsically synthesize type I collagen.

Animals↗
PubMed1999

Relation of bimanual coordination to activation in the sensorimotor cortex and supplementary motor area: analysis using functional magnetic resonance imaging.

The aim of this study was to analyze how functional activation in the supplementary motor area (SMA) and sensorimotor cortex (SMC) is related to bimanual coordination using functional magnetic resonance imaging. Subjects included 24 healthy volunteers, 15 of whom were right-handed and 9 left-handed. Three kinds of activation tasks, all of which required the repetitive closing and opening of a fist, were performed: unimanual movement of the nonpreferred hand (task A); simultaneous, agonistic movement of both hands (task B); simultaneous, antagonistic movement of both hands (task C). The SMA activation during task C was more pronounced than that during the other two tasks for right and left handers. The results suggested that the activation of the SMA, at least during a simple motion used in the present study, was little influenced by whether the motion was unimanual or bimanual but instead how the bimanual motion was composed of the motion element of a single hand. The SMC activation during task C was significantly larger than that during task B, whereas hemispheric differences in the activation were not found. This indicated that the complexity of the bimanual movement also affected the SMC activation.

Adult↗