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Biomedical subjects

M Murakami

Publications and source records attributed to M Murakami.

At least 487 records · Page 27Linked to original sources
PubMed1997

Mouse bone marrow-derived mast cells undergo exocytosis, prostanoid generation, and cytokine expression in response to G protein-activating polybasic compounds after coculture with fibroblasts in the presence of c-kit ligand.

Polycationic mast cell activators, such as compound 48/80 and substance P, have been reported to activate connective tissue-type mast cells specifically by interacting directly with the Gi family of trimeric GTP-binding protein. We now demonstrate that mouse bone marrow-derived mast cells (BMMC) developed in IL-3, an immature mast cell population lacking responsiveness to the Gi-coupled polycationic mast cell activators, underwent maturation toward a connective tissue-type mast cells-like phenotype that responded to polycationic compounds after only 4 to 6 days of coculture with Swiss 3T3 fibroblasts in concert with recombinant soluble c-kit ligand (KL), whereas 3T3 or KL alone was insufficient to mediate this process. Under optimal conditions, cocultured BMMC released approximately 30% beta-hexosaminidase and generated approximately 1 ng of PGD2/10(6) cells within a few minutes in response to compound 48/80 or substance P. Furthermore, these cells expressed cytokines, such as IL-1beta and IL-6, and PG endoperoxide synthase-2 1 to 4 h after stimulation with compound 48/80 or substance P. All these responses were suppressed effectively by pertussis toxin, implicating functional Gi coupling. Regardless of the remarkable change in polycationic compound sensitivity, there was only a minimal change in the constitutive expression of Gi3 alpha after coculture. These results together with the observation that before coculture BMMC responded to thrombin through its Gi-coupled receptor suggest that the alteration in a certain step(s) distinct from the level of Gi3 alpha protein expression is important for the acquisition of responsiveness to the polycationic compounds by the synergistic action of KL and 3T3 fibroblast-derived factor. Several lines of evidence have revealed that 3T3-derived factor appears to differ from the known cytokines, prostanoids, and adhesion molecules and is a labile soluble substance.

3T3 Cells↗
PubMed1997

Micro-magnetic resonance imaging of the inner ear in the guinea pig.

We applied a magnetic resonance microscopy at 7.05 T with a gradient coil unit to image the fine structure of the guinea pig cochlea. First, a three-dimensional MR image of the surface of the cochlea was obtained to select the location of cross-sectional images. Then, cross-sectional images of the basal turn, the second turn and the apical turn of the cochlea were obtained. Based upon the different protein concentrations of the endolymph vs the perilymph, the scala vestibuli, scala tympani and the cochlear duct could be clearly distinguished. This allowed a determination of the location of both the basilar membrane and Reissner's membrane. We raise the possibility that MRM may become useful in the diagnosis of endolymphatic hydrops (Meniere's disease).

Animals↗
PubMed1997

Relation of iodine-123 metaiodobenzylguanidine myocardial scintigraphy to endomyocardial biopsy findings in patients with dilated cardiomyopathy.

BACKGROUND: Iodine-123 metaiodobenzylguanidine (123I-MIBG) concentrates in adrenergic neurons and has been developed for evaluation of the sympathetic nervous system. Recent studies have demonstrated that the normal heart is clearly visualized by 123I-MIBG cardiac scintigraphy, whereas abnormal 123I-MIBG myocardial uptake and washout have been demonstrated in patients after myocardial infarction and in patients with congestive cardiomyopathy, long QT syndrome, and ventricular tachycardia. HYPOTHESIS: Based on evidence from recent studies, it can be hypothesized that 123I-MIBG uptake is related to histopathologic changes in the myocardium. METHODS: The relation of 123I-MIBG uptake to the histologic findings for the heart was studied in 24 patients with dilated cardiomyopathy (DCM). The study group did not include patients with complicating disorders that primarily affect the adrenergic nervous system. The 123I-MIBG uptake was visually assigned one of four grades using the two criteria of the mean score for six regional uptake grades (mean score) and the global score obtained by visual evaluation of the entire image (global score). The 123I-MIBG uptake score was also determined for the region at which the biopsy specimen was obtained (biopsy region score). The histologic findings were evaluated by assigning one of four grades for each of the following five factors: myocyte hypertrophy, myocardial fibrotic change, myocyte degeneration and necrosis, mononuclear cell infiltration, and myocyte disarray. The sum for all grades was defined as the total score, and the global score was also assigned to the overall histologic findings. RESULTS: All of the global, mean, and biopsy region scores for 123I-MIBG uptake correlated significantly with the global and total scores for the histologic findings. Among the histologic factors, myocyte degeneration showed score correlated with all global, mean, and biopsy region scores for the uptake. Myocyte hypertrophy was associated weakly with the 123I-MIBG uptake scores. CONCLUSION: These results indicate that 123I-MIBG uptake imaging is associated with histopathologic abnormalities in patients with DCM.

3-Iodobenzylguanidine↗
PubMed1997

Cryopreservation of mature bovine oocytes following centrifugation treatment.

In vitro matured bovine oocytes were frozen slowly in 1.6 M 1,2-propanediol following centrifugation treatment for polarization of lipid droplets in the cytoplasm. After thawing, the survival of the oocytes was assessed morphologically and also by in vitro fertilization and culture. The polarization of cytoplasmic lipid droplets had a negative effect on the survival of frozen-thawed oocytes. Thus, this treatment did not improve the frequency of normal fertilization and development to blastocysts, compared with that of frozen control oocytes. However, the frequency of polyspermy and activation of lipid-polarized oocytes that survived after freezing-thawing and subsequent in vitro fertilization tended to be less than those of surviving control oocytes. In addition, the effect of centrifugation treatment was to produce a small but significant increase in the cleavage rate of oocytes that survived after freezing-thawing and the development rates to blastocysts of surviving lipid-polarized oocytes tended to increase, compared with those of surviving control oocytes. These results suggest that the freezing tolerance of the spindle and other organelles of in vitro matured bovine oocytes is associated with lipid droplets and may be improved by the polarization of cytoplasmic lipid droplets before cryopreservation.

Animals↗
PubMed1997

Short-term exposure to diesel exhaust induces nasal mucosal hyperresponsiveness to histamine in guinea pigs.

The increasing prevalence of allergic rhinitis in many countries is becoming a social problem. It is important to determine whether air pollutants are related to the increase in the prevalence rate of allergic rhinitis or not. In this respect, it is necessary to elucidate whether exposure to air pollutants affects the nasal mucosa and causes nasal mucosal hyperresponsiveness to chemical mediators released by antigen-antibody reactions. A previous study revealed that diesel exhaust particulates are potent in augmenting increases in nasal congestion and nasal secretion induced by histamine (T. Kobayashi and T. Ito, 1995, Fundam. Appl. Toxicol. 27, 195-202). In the present study, using a rhinitis model of guinea pigs, we investigated whether short-term (3-hr) exposure to diesel exhaust induces nasal mucosal hyperresponsiveness to histamine. Guinea pigs of each group were exposed to filtered air or to a low or high concentration of diesel exhaust (1 and 3.2 mg/m3 particulates in diluted diesel exhaust, respectively) for 3 hr. After diesel exhaust exposure, sneezing frequency, nasal secretion from the nostril, and intranasal airway resistance induced by histamine were measured as indices of sneezing response, rhinorrhea, and nasal congestion, respectively. Short-term exposure to a low or high concentration of diesel exhaust itself did not induce sneezing, nasal secretion, or nasal congestion. However, short-term exposure to a high concentration of diesel exhaust augmented sneezing and nasal secretion, but not nasal congestion, induced by histamine. In conclusion, short-term exposure to diesel exhaust potently induces nasal mucosal hyperresponsiveness.

Aerosols↗
PubMed1997

Recurrent colonic cancer developing at the site of a stapled stump: report of a case.

We report herein the case of a 54-year-old woman who developed a recurrence of carcinoma in a stapled colon stump 2 years after undergoing an anterior resection for carcinoma of the rectosigmoid colon. At this time an end to end anastomosis (EEA) stapler had been used to perform a side-to-end anastomosis. The implantation of cancer cells was thought to have caused the recurrence.

Anastomosis, Surgical↗
PubMed1997

Response of the extramedullary lung plasmacytoma with pleural effusion to chemotherapy.

An elderly patient with extramedullary lung plasmacytoma and subsequent pleural effusion is described. The presence of abnormal plasma cells in the pleural fluid led to diagnosis. Histologically similar conditions such as multiple myeloma and solitary myeloma of bone were ruled out by clinical evaluation. These neoplasms usually occur in the head and neck area and are not characterized by paraprotein accumulation. Few cases in the lung have been reported. We describe a case of extramedullary plasmacytoma of the lung with plasmacytoma-induced pleural effusion and the presence of monoclonal paraprotein in both the serum and urine. Chemotherapy with melphalan was effective in reducing the size of the plasmacytoma, and pleurodesis was used to manage the pleural effusion.

Aged↗
PubMed1997

Dimethylthiourea reduces pancreatic islet-cell damage in DBA/1 sucking mice with reovirus type-2 infection.

Reovirus type 2 (Reo-2) infection in DBA/1 sucking mice causes pancreatic islet-cell destruction, which results in a diabetes-like syndrome. To investigate the role of reactive oxygen species (ROS), the protective effect of dimethylthiourea (DMTU) was examined, this substance being an effective scavenger of hydroxyl radicals. The degree of cellular infiltration in and around pancreatic islets was the same in mice receiving either virus only or virus and DMTU. The latter had no effect on (1) the number or type of white blood cells, (2) lymphocyte function-associated antigen 1-alpha-positive splenocytes, or (3) viral multiplication in the pancreas. However, treatment with DMTU inhibited the elevation of blood glucose concentrations and reduced pancreatic islet-cell damage (beta-cell degranulation and necrosis). These results suggest that ROS play a role in the pathogenesis of Reo-2-induced diabetes-like syndrome.

Animals↗
PubMed1997

Immunohistochemical examination of proliferative potentials and the expression of cell cycle-related proteins of intracranial chordomas.

The difference in biological features between recurrent and nonrecurrent intracranial chordomas has not been studied. In this study, proliferative potentials of chordomas were studied with an immunohistochemical staining method, mainly using anti-Ki-67 antibody, MIB-1, which is known to be available for archival paraffin sections, together with immunohistochemical studies on the expression of cell cycle or apoptosis-related proteins, including p53, cyclin D1, and bcl-2 proteins. The correlation among MIB-1 staining indices, the immunoreactivities of these proteins, and clinical courses of intracranial chordomas were analyzed retrospectively, and the statistically significant correlation between MIB-1 staining index (SI) and recurrence has been clarified. The mean MIB-1 SI of recurrent tumors was 10.2%, being shown to be higher than that of nonrecurrent tumors (2.8%). The immunohistochemically positive staining of cell cycle-related protein, especially p53 and cyclin D1 proteins, correlated well with recurrence and high MIB-1 SI. In conclusion, both the examination of proliferative potentials of chordomas using MIB-1 SI and the study of the immunoreactivity of p53 and cyclin D1 proteins are important for their biological and histopathological analyses and the prediction of future recurrence.

Adolescent↗
PubMed1997

Association between attitudes toward health promotion and opinions regarding organ transplants in Japan.

Health promotion activities to educate the public about health lifestyles have been performed widely in industrialized countries where chronic adult diseases have become prevalent. According to a basic principle of health promotion activities, the symptoms of many diseases are regarded as the result of inadequate health behavior, curable by modifying health behavior. It is thus possible that an exposure to health promotion activities might instill negative attitudes towards organ transplants, because program participants may conclude that persons who need an organ transplant have become unhealthy as the result of their own poor health habits. In this study, two types of surveys were undertaken to test this hypothesis. The subjects of the first cross-sectional study were 712 male and female Japanese citizens, and those of the second case-control study were 240 female company employees in Japan. In the first study, a logistic regression analysis was used and the following findings were obtained. (1) Compared with the persons who felt that they did not have enough practical knowledge about individual health practices, those who felt that they had adequate knowledge were 0.66 times less likely to support organ transplants. (2) Compared with those who were not willing to spend money on healthful things, the persons who were willing to do so were 0.51 times less likely to support organ transplants. In the second case-control study, it was revealed that the subjects who had negative attitudes towards organ transplants had consistently healthier lifestyles than did those who had positive attitudes towards organ transplants. Based upon the present findings and the nature of the basic principles of health promotion activities, we infer that community health promotion activities have a negative influence upon citizens' opinions of organ transplants. Since these findings have health policy implications, more studies are necessary to conclusively evaluate the effects of health promotion activities upon attitudes toward organ transplants.

Attitude to Health↗
PubMed1997

The effect of sperm-oocyte incubation time on in vitro embryo development using sperm from a tetraparental chimeric bull.

The present study was designed as 5 x 4 factorial to investigate the effects of using sperm from 5 bulls, and varied sperm-oocyte incubation times (5, 10, 15 and 20 h) on the fertilization, cleavage rates and blastocyst formation on an in vitro bovine embryo production system. The bulls included a tetraparental Chimera, its sires (Japanese Black and Limousin), its maternal grand-sires (Japanese Brown and Holstein). The proportion of polyspermy, 2-pronuclei formation, fertilization, cleavage and development to blastocyst were affected (P < 0.001) by the duration of sperm-oocyte incubation, as well as by the interaction between bulls and their corresponding sperm-oocyte incubation time. Blastocyst rate observed after 5 h in oocytes inseminated with Chimera, Japanese Black and Limousin were higher (p < 0.05) than those observed at 20 h incubation. The proportion of blastocysts from oocytes inseminated with Japanese Black observed at 10 h of incubation did not differ from that of Chimera, but both were higher (p < 0.05) than those observed for the Limousin, Japanese Brown and Holstein sires. The present study showed that there was an effect by the duration of sperm-oocyte incubation on in vitro embryo development. The optimal time of sperm-oocyte incubation for the Chimera was similar to that of its sires (Japanese Black and Limousin) but differed from its maternal grand-sires (Japanese Brown and Holstein). The fertilization rates for the sperm from the Holstein bull increased up to 15 h suggesting that this might be the only bull that would benefit from a long incubation period for insemination.

Animals↗
PubMed1997

Transgenic mouse models for B-cell dominant autoimmune diseases.

To study the molecular mechanism for the development of B-cell dominant autoimmune diseases, several autoantibody transgenic mouse models were established. These studies have revealed that the escape of autoreactive B cells from clonal deletion or functional inactivation (clonal anergy) alone is not enough to develop autoimmune disease. Indeed, additional factors such as infections, cytokines and the costimulatory help of T cells are required for the activation of autoreactive B cells. The requirement for activation of autoreactive clones is also shown for the development of T-cell dominant autoimmune diseases in a T-cell receptor transgenic model. These findings will clarify the two-step mechanism of autoimmune disease: appearance and activation of autoreactive lymphocytes.

Animals↗
PubMed1997

Elevated plasma levels of interleukin-6, interleukin-8, and granulocyte colony-stimulating factor during and after major abdominal surgery.

STUDY OBJECTIVE: To evaluate the influence of major abdominal surgery on the plasma levels of inflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8) and granulocyte colony-stimulating factor (G-CSF). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: 10 ASA physical status I and II patients undergoing upper abdominal surgery. INTERVENTIONS: All patients received combined general-epidural anesthesia with isoflurane and nitrous oxide, after insertion of an epidural catheter at T7-T9 dosed with 1.5% lidocaine. MEASUREMENTS AND MAIN RESULTS: Plasma cytokine (IL-6, IL-8, G-CSF) levels were determined with an enzyme-linked immunosorbent assay (ELISA) at pre-anesthesia, 0, 2, and 4 hours during surgery, and at the end of surgery, followed by sampling on the morning of postoperative days 1 (POD1) and 3 (POD3). Plasma cortisol levels were also determined. The plasma levels of IL-6 increased gradually after skin incision and reached the maximal value at the end of surgery (p < 0.001). IL-8 levels also increased from the baseline value to their maximum at the end of surgery (p < 0.05). G-CSF levels were elevated from the pre-anesthesia value to their maximum by the end of operation (p < 0.005). Plasma cortisol levels were increased after skin incision (p < 0.001). Postoperative cytokine levels correlated significantly with each other (r = 0.68, p < 0.05 for IL-6 vs. IL-8; r = 0.81, p < 0.005 for IL-6 vs. G-CSF; and r = 0.84, p < 0.005 for IL-8 vs. G-CSF). Postoperative IL-6 levels and intraoperative blood loss correlated significantly (r = 0.64, p < 0.05). CONCLUSIONS: These results suggest that major upper abdominal surgery stimulates the release of inflammatory cytokines presumably from the operation site. Further study is warranted to evaluate the modulation of inflammatory responses in the perioperative period.

Abdomen↗
PubMed1997

Kawaguchipeptin B, an antibacterial cyclic undecapeptide from the cyanobacterium Microcystis aeruginosa.

Kawaguchipeptin B, an antibacterial cyclic undecapeptide, was isolated from the cultured cyanobacterium Microcystis aeruginosa (NIES-88). Its structure was elucidated as 1 on the basis of 2D NMR data and chemical degradation. Kawaguchipeptin B (1) inhibited the growth of the Gram-positive bacterium Staphylococcus aureus at a concentration of 1 microgram/mL (MIC).

Anti-Bacterial Agents↗