Search PubMed⌕ Search

Biomedical subjects

M Murakami

Publications and source records attributed to M Murakami.

At least 55 records · Page 3Linked to original sources
PubMed2004

Validation of neoclassical bootstrap current models in the edge of an H-mode plasma.

Analysis of the parallel electric field E(parallel) evolution following an L-H transition in the DIII-D tokamak indicates the generation of a large negative pulse near the edge which propagates inward, indicative of the generation of a noninductive edge current. Modeling indicates that the observed E(parallel) evolution is consistent with a narrow current density peak generated in the plasma edge. Very good quantitative agreement is found between the measured E(parallel) evolution and that expected from neoclassical theory predictions of the bootstrap current.

Journal Article↗
PubMed2004

Identifying patterns of spatial current dispersion that characterise and separate the Brugada syndrome and complete right-bundle branch block.

The aim of the study was to detect patterns of spatial-current distribution in the late QRS and early ST-segments that distinguish Brugada-syndrome cases from complete right-bundle branch block (CRBBB). Magnetocardiograms (MCGs) were recorded from Brugada-syndrome patients (n = 6), CRBBB patients (n = 4) and the members of a control group (n = 33). The current distributions at six time points from Q-onset were estimated by producing current-arrow maps (CAMs). The angle of the current arrow of maximum amplitude at each time point was calculated. In the Brugada cases, the characteristic ST elevation was seen above the upper right chest, and abnormal currents appeared to be present in the right-ventricular outflow tract (RVOT). The angles of the abnormal arrows were -78 degrees +/- 51 degrees at 100 ms and -50 degrees +/- 61 degrees at 110 ms. In the cases of CRBBB, wide S- and R-waves were recorded above the upper right and lower right chest, respectively. The angles of the abnormal arrows for CRBBB were 152 degrees +/- 19 degrees at 100 ms, 159 degrees +/- 20 degrees at 110 ms, and 157 degrees +/- 19 degrees at 120 ms. The findings suggest that an abnormal current from the RVOT to the upper left chest may be a feature of the Brugada syndrome, and that the direction of this current is completely different from that seen in CRBBB.

Adult↗
PubMed2004

Effect of peripheral blood progenitor cell dose on hematopoietic recovery: identification of minimal progenitor cell requirements for rapid engraftment.

Repeated high-dose chemotherapy (HDC) with stem cell support is advocated for curative treatment of epithelial ovarian cancer patients, requiring large quantities of progenitor cell harvest. Although the switchover to peripheral blood stem cell transplantation has generally made possible the harvest of large quantities of progenitor cells, the minimum threshold is still pertinent for planning the safe conduct of HDC. However, as the minimum threshold for safe peripheral blood stem cell transplantation (PBSCT) is not yet established, this study was designed to clarify the minimum amount of progenitor cells required for prompt recovery of hematopoietic. Retrospective analysis was performed on 52 HDCs administered in 37 ovarian cancer patients. After autologous bone marrow aspiration (10 patients) or peripheral blood stem cell harvest (27 patients), colony-forming unit granulocyte macrophage (CFU-GM) were enumerated prior to cryopreservation. Numbers of CFU-GM were again calculated before reinfusion and the patients were divided into eight groups: 0.13-<0.4, 0.4-<0.7, 0.7-<1.0, 1.0-<3.5, 3.5-<5.0, 5.0-<10.0, 10.0-<20.0 and >20.0 (x 10(5)/kg). The minimum CFU-GM threshold (x 10(5)/kg) was found to be 1.0-<3.5 for platelets and 3.5-<5.0 for white blood cells. Higher infusion doses did not lead to significant benefits in hematopoietic reconstruction. These results indicate that preservation of a minimum of 7-10 x 10(5)/kg CFU-GM is recommended for the safe conduct of tandem HDCs.

Female↗
PubMed2004

Characterization of the expression and function of N-methyl-D-aspartate receptor in keratinocytes.

The N-methyl-D-aspartate (NMDA) receptor is expressed on neural tissue where it gates calcium ion entry upon stimulation. Using immunohistochemistry, it has been demonstrated in this study that the NMDAR1 receptor is also expressed on keratinocytes (KCs) in normal human skin and inflamed psoriatic skin in vivo. Furthermore, the NMDA receptor was functional as demonstrated by the ability of this receptor to trigger Ca++ influx in KCs. Incubation of cultured, human KCs with MK-801 decreases the cell growth and induces an increase in apoptosis. These findings demonstrate that the KC expression of NMDA receptor is a mechanism through which the influx of Ca++ into the cell can be regulated and suggest that the expression of this receptor may play a role in the regulation of KC growth and differentiation.

Apoptosis↗
PubMed2004

Structural analysis of a new anti-hypertensive peptide (beta-lactosin B) isolated from a commercial whey product.

Angiotensin-converting enzyme (ACE) inhibitory activities and anti-hypertensive activities in spontaneously hypertensive rats (SHR) of 12 kinds of commercial peptides of food additive grade were measured. Four peptide products derived from milk proteins showed strong anti-hypertensive activities (>-18.0 mm Hg). A sample of WE80BG derived from whey proteins showed the strongest anti-hypertensive activity (-21.2 +/- 16.9 mm Hg) with a medium level of ACE inhibitory activity (53.6%), and it was subjected to hydrophobic and gel filtration chromatography. From the low molecular weight fraction, an anti-hypertensive peptide was isolated by using reversed-phase HPLC, and it was found to be a tetrapeptide, alanine-leucine-proline-methionine (Ala-Leu-Pro-Met, ALPM), the origin of which was estimated to be beta-lactoglobulin f 142 to 145. At 8 h after oral administration of ALPM in SHR, systolic blood pressure was significantly decreased (-21.4 +/- 7.8 mm Hg), but the IC50 value (concentration of peptide needed to inhibit 50% of the ACE activity) of ALPM was not so high. We named the Ala-Leu-Pro-Met "beta-lactosin B." This peptide is the second anti-hypertensive peptide found from beta-lactoglobulin. Because WE80BG containing ALPM was also found to show the strongest anti-hypertensive activity (-24.5 +/- 10 mm Hg) at 8 h after oral administration in SHR, WE80BG would be suitable for application to the development of a new food expected to have anti-hypertensive effects.

Amino Acids↗
PubMed2004

Roles of endogenous prostaglandins and cyclooxygenase izoenzymes in mucosal defense of inflamed rat stomach.

Endogenous prostaglandins (PGs) are involved in adaptive gastric protection against acute injury, and cyclooxygenase (COX)-1 is responsible for the production of PGs in this phenomenon. In the present study, we examined the effect of various COX inhibitors on gastric ulcerogenic and acid secretory responses following daily exposure of the stomach to iodoacetamide (IA) and investigated the role for COX isozyme in gastric protection under subchronic mucosal irritation. Gastric mucosal irritation was induced by addition of 0.1% IA to drinking water, and the gastric mucosa was examined on the 6th day. Indomethacin (5 mg/kg) or SC-560 (selective COX-1 inhibitor, 5 mg/kg) or rofecoxib (selective COX-2 inhibitor, 5 mg/kg) was given p.o. twice 24 hr and 3 hr before the termination of IA treatment. Giving IA in drinking water for 5 days produced minimal damage in the stomach. The damage was significantly worsened by indomethacin, resulting in hemorrhagic lesions. Both SC-560 and rofecoxib also aggravated such lesions, although the effect of rofecoxib was more pronounced. Treatment with IA decreased acid secretion in pylorus-ligated stomachs, and this change was significantly reverted by indomethacin as well as SC-560 and rofecoxib. Mucosal PGE2 content was increased following IA treatment, with apparent expression of COX-2 mRNA in the stomach, and the increased PGE2 production was significantly suppressed by SC-560 and rofecoxib as well as indomethacin. These results suggest that endogenous PGs derived from both COX-1 and COX-2 are involved in the mucosal defense of the inflamed stomach, partly by decreasing acid secretion and contribute to maintaining the mucosal integrity under such conditions.

Administration, Oral↗
PubMed2004

Effects of indomethacin and rofecoxib on gastric mucosal damage in normal and Helicobacter pylori-infected mongolian gerbils.

This study examined the effects of indomethacin and rofecoxib on normal and Helicobacter pylori (H. pylori)-infected gastric mucosa of Mongolian (M.) gerbils. M. gerbils (6-wk-old) were orally administered H. pylori (ATCC43504, 2 x 10(8) CFU/ml) after fasting for 24 hours. Beginning 3 mo after inoculation, indomethacin (2 mg/kg, s.c) or rofecoxib (10 mg/kg, p.o.) was administered once daily for 2 wk to the gerbils. At autopsy, gastric mucosal ulcer area, myeroperoxidase (MPO) activity, prostaglandin (PG) E(2) synthesis, and H. pylori viability were determined. Histamine-stimulated gastric acid secretion was measured with the acute gastric fistula method. Histological study was performed with H&E staining. H. pylori infection caused severe mucosal damage and production of lymphoid follicles in the gastric submucosa. In H. pylori-infected gerbils, indomethacin aggravated the gastric mucosal damage induced by H. pylori infection. Furthermore, indomethacin by itself induced gastric ulcers at an incidence of 6/10. In contrast, rofecoxib did not aggravate the H. pylori-induced mucosal damage. Indomethacin and rofeocoxib significantly reduced H. pylori viability. MPO activity was significantly increased in H. pylori-infected gerbils compared with H. pylori-uninfected gerbils. Indomethacin and rofecoxib reduced MPO activity in H. pylori-infected gerbils. PGE(2) synthesis was markedly increased in H. pylori-infected gerbils (approximately 3-times) compared with the normal gerbils. Indomethacin significantly inhibited PGE(2) synthesis in the gastric mucosa, both in normal and H. pylori-infected gerbils. Rofecoxib did not reduce PGE(2) synthesis in normal gerbils, however, PGE(2) synthesis was reduced to normal levels in H. pylori-infected gerbils. In H. pylori-infected gerbils, histamine-stimulated gastric acid secretion was reduced compared with normal gerbils. Indomethacin significantly increased histamine-stimulated gastric acid secretion and rofecoxib tended to increase secretion in H. pylori-infected gerbils. It was concluded that indomethacin enhances development of gastric mucosal damage in normal gerbils and aggravates H. pylori-induced gastric damage, resulting in gastric ulcers. Rofecoxib did not induce gastric damage in normal gerbils and did not aggravate damage in H. pylori-infected gerbils, suggesting that rofecoxib is less damaging to the stomach than indomethacin.

Administration, Oral↗
PubMed2004

Glycoconjugates with NeuAc-NeuAc-Gal-Glc are more effective at preventing adhesion of Helicobacter pylori to gastric epithelial cells than glycoconjugates with NeuAc-Gal-Glc.

Helicobacter pylori (H. pylori) adheres to human gastric epithelial cells, eliciting various gastroduodenal diseases. Gangliosides play a critical role in bacterial adhesion to cell surfaces. The present study examined how residues of gangliosides are important for inhibition of adhesion of H. pylori to MKN-45 cells. We measured adhesion or detachment effects of gangliosides on the interaction between MKN-45 cells and H. pylori, as well as interleukin-8 production. Among the gangliosides, O-Ac-GD3, GT(1b), GD(1a), GD(1b), GT(1a), and GD3 had potent dose dependent inhibitory effects on adhesion of H. pylori to MKN-45 cells, interleukin-8 production, and vacuole formation induced by H. pylori toxin binding to Vero cells. GD3 also accelerated bacterial detachment of MKN-45 cells with adherent H. pylori in a dose dependent manner. Such results strongly suggest that the mechanism involved in the inhibition of H. pylori adhesion is mediated by the variations of the residues of the NeuAc-NeuAc-Gal-Glc chain of gangliosides. NeuAc-NeuAc-Gal-Glc exhibits a more inhibitory effect on adhesion than the NeuAc-Gal-Glc chain. Such gangioside and oligosaccrharide sequences appear to have therapeutic importance for prevention of H. pylori adhesion, as well as reduction of both inflammation and gastric mucosal injuries.

Animals↗
PubMed2003

Modification of the current profile in high-performance plasmas using off-axis electron-cyclotron-current drive in DIII-D.

Recent DIII-D experiments using off-axis electron cyclotron current drive (ECCD) have demonstrated the ability to modify the current profile in a plasma with toroidal beta near 3%. The resulting plasma simultaneously sustains the key elements required for Advanced Tokamak operation: high bootstrap current fraction, high beta, and good confinement. More than 85% of the plasma current is driven by noninductive means. ECCD is observed to produce strong negative central magnetic shear, which in turn acts to trigger confinement improvements in all transport channels in the plasma core.

Journal Article↗
PubMed2003

First results from KamLAND: evidence for reactor antineutrino disappearance.

KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.

Journal Article↗
PubMed2003

Successful treatment by spinal cord stimulation for gait disturbance in a patient with diffuse axonal injury.

The authors present a case of diffuse axonal injury (DAI) treated by cervical spinal cord stimulation (C-SCS) for gait disturbance. The patient had right hemiparesis of moderate degree, mild ataxia, ideational apraxia and gait disturbance, when admitted to our hospital for rehabilitation. He could not walk by himself, nevertheless neurorehabilitation was done for four months. Xenon-CT was examined by C-SCS loading and the changes of regional cerebral blood flow were significantly increased in both hemispheres, especially in the thalamus. C-SCS was performed continuously on condition of 25 Hz, 200 microsec and 0.5 V, daily for a month. Neurological deficits, especially gait disturbance due to ideational apraxia, were gradually improved after initiation of C-SCS, and the patient could walk by himself. We speculate that C-SCS played a role in triggering improvement of gait disturbance at the chronic stage in our case, and SCS may be helpful for neurorehabilitation of focal symptoms after DAI.

Adult↗
PubMed2003

Classifying cases of fetal Wolff-Parkinson-White syndrome by estimating the accessory pathway from fetal magnetocardiograms.

The paper presents an evaluation of the possibility of using fetal magnetocardiogram (FMCG) signals to estimate and classify the accessory pathway in fetal Wolff-Parkinson-White (WPW) syndrome. The FMCG signals of two fetuses with WPW syndrome (type A) were detected using a 64-channel superconducting quantum-interference device system. An average across the cycles of these signals was taken to obtain clear WPW signals. To determine the direction and position of the accessory pathway in a fetal heart accurately, the accessory pathway and activated pathway at the peak of the QRS complex thus obtained were estimated for each fetus, using a single-dipole model. The phase angle (about 90 degrees) between the equivalent current dipoles (ECDs) was the same for both fetuses. This angle suggested that the accessory pathway is in the left side of the heart, i.e. that the pathway exists in the left ventricle, which indicates type A WPW syndrome. Identification of the position of the accessory pathway in a fetus with WPW syndrome from the angle between the ECD of the accessory pathway and the ECD of the peak in the QRS complex was thus demonstrated.

Electrocardiography↗
PubMed2003

Intracranial plasma cell granuloma with genetic analysis.

BACKGROUND: Plasma cell granuloma of the central nervous system is rare and less than 30 cases have been reported in literature. METHOD/FINDINGS: A 64-year-old woman complained of headache, and computed tomography (CT) and magnetic resonance (MR) imaging of the brain revealed a tumour at the right anterior-third parasagittal region which led us to diagnose a parasagittal meningioma. We performed total resection of the tumour and the pathological diagnosis was plasma cell granuloma. Polymerase chain reaction (PCR) analysis of immunoglobulin heavy chain (IgH) gene rearrangements produced no monoclonal band. This patient underwent no supplementary treatment and no recurrent tumour was observed for 3 years. INTERPRETATION: A case of plasma cell granuloma which is diagnosed with genetic analysis is presented. An analysis of the clonality using the PCR procedure would play an important role in supporting the pathological and clinical diagnosis.

Brain Diseases↗
PubMed2003

Effects of cooling ovaries before oocyte aspiration on meiotic competence of porcine oocytes and of exposing in vitro matured oocytes to ambient temperature on in vitro fertilization and development of the oocytes.

Experiments were conducted to evaluate the effects of cooling porcine ovaries to low temperature (4 degrees C, 15 degrees C, 20 degrees C, 25 degrees C or 30 degrees C) for 1 h on the meiotic competence of their oocytes. Moreover, it was determined whether or not the exposure of in vitro matured oocytes to ambient temperature (20 degrees C, 25 degrees C or 30 degrees C) for 1 h affects the fertilization and developmental competence of the oocytes. There was no difference between the proportions of oocytes that underwent maturation to metaphase II when isolated from control ovaries held at 35 degrees C and ovaries exposed to 30 degrees C. However, the percentages of oocytes from ovaries exposed to 25 degrees C or less were significantly lower than those of oocytes from ovaries exposed to 30 degrees C and control ovaries. The proportions of total and normal fertilization of oocytes that had been exposed to 20 degrees C before in vitro fertilization (IVF) were significantly lower than those of control oocytes maintained at 38.5 degrees C. However, cooling in vitro matured oocytes had no effects on their cleavage and development to blastocysts after IVF. These data suggest that exposing porcine ovaries to a low temperature of 25 degrees C or less before aspiration of oocytes may adversely affect their subsequent in vitro maturation. It may be necessary to maintain the oocytes at a temperature of more than 25 degrees C during manipulation of oocytes for retaining the fertilizability of the oocytes.

Animals↗
PubMed2003

Successful treatment of bcr/abl-positive acute mixed lineage leukemia by unmanipulated bone marrow transplantation from an HLA-haploidentical (3-antigen-mismatched) cousin.

We describe a patient with bcr/abl-positive acute mixed lineage leukemia who successfully underwent transplantation in primary induction failure, using unmanipulated bone marrow from a human leukocyte antigen (HLA)-haploidentical cousin. The tumor burden was successfully reduced by the administration of imatinib mesylate (STI571) before transplantation. As graft-versus-host disease (GVHD) prophylaxis, a combination of tacrolimus and a short course of methotrexate, methylprednisolone, and mycophenolate mofetil was used. Hematopoietic reconstitution was rapid, and acute GVHD was limited to the skin (grade I). The patient is still in complete remission past day +400. This successful case suggests that HLA-haploidentical transplantation using unmanipulated marrow from a distantly related relative can be considered for patients in urgent situations who do not have HLA-identical donors.

Adult↗
PubMed2003

Effects of hormone replacement therapy on weight, abdominal fat distribution, and lipid levels in Japanese postmenopausal women.

OBJECTIVE: To investigate the effects of hormone replacement therapy (HRT) on weight, abdominal fat distribution, and fasting lipid levels in Japanese postmenopausal women (PMW). DESIGN: Prospective, 12-month-controlled clinical comparison of women with and without HRT. SUBJECTS: In all, 35 PMW with HRT (conjugated estrogens, 0.625 mg daily; medroxyprogesterone acetate, 2.5 mg daily; HRT group) and 26 PMW without HRT (control group). MEASUREMENTS: Weight, abdominal fat distribution by computed tomographic measurements, lipid profiles, and sex hormones were determined at baseline and after 12 months of treatment or observation. RESULTS: Weight did not change in any group. Visceral abdominal fat increased in controls, but not in the HRT group. Total and low-density lipoprotein cholesterol decreased, and triglyceride (TG) and high-density lipoprotein cholesterol increased in the HRT group; these did not change in the control group. When we divided women into those with android and gynoid types of abdominal fat distribution. Subjects with an android distribution showed reduced visceral fat with HRT, which also decreased the proportion of patients maintaining an android distribution. HRT did not alter abdominal fat distribution in subjects with a gynoid distribution. HRT increased serum TG in the android and the gynoid subgroups. CONCLUSION: Improved distribution of abdominal fat and fasting lipid levels except for TG may represent beneficial effects of HRT with respect to cardiovascular disease, but caution is warranted concerning TG elevation from HRT performed in PMW.

Abdomen↗
PubMed2003

Tomatoes have natural anti-thrombotic effects.

The prevention of arterial thrombotic diseases has a high priority in developed countries. An inappropriate diet may be an important risk factor for thrombotic events. The daily intake of an anti-thrombotic diet may offer a convenient and effective way of prevention. The aim of the present study was to test tomato extracts for anti-thrombotic effects and to identify those varieties that have such an effect. A shear-induced platelet-function test (haemostatometry) was used to test anti-thrombotic potential in vitro. Extracts from those tomato varieties that showed a significant anti-thrombotic activity in vitro were further assessed in vivo, using a laser-induced thrombosis test in mice. One tomato variety (KG99-4) showed significant anti-thrombotic activity both in vitro and in vivo. KG99-4 inhibited not only platelet-rich thrombus formation but also had a thrombolytic effect. It is concluded that haemostatometry can detect and classify the anti-thrombotic potential of fruits and vegetables and offers a simple way of screening for such effects.

Animals↗