Biomedical subjects

M Ohnishi

Publications and source records attributed to M Ohnishi.

At least 19 recordsLinked to original sources

PubMed2007

Selection of lactic yeast producing glucosylceramide from cheese whey.

From 2150 isolates from raw milk and milk products, yeast strains were surveyed to produce glucosylceramide from cheese whey. Most of the 54 strains that had accumulated a detectable amount of glucosylceramide were identified as Kluyveromyces lactis var. lactis. The cells of K. lactis var. lactis strain M-11 derived from domestic raw milk accumulated glucosylceramide 2.5-fold higher than K. lactis var. lactis NBRC 1267, the reference strain selected from the culture collections. Strain M-16 of K. lactis var. lactis derived from the same origin was found to synthesize a considerable amount of steryl glucoside in addition to glucosylceramide. Sequence analysis of ribosomal DNA intergenic spacer two regions revealed that strains M-11 and M-16 were diverged from a type strain of K. lactis var. lactis in the same species.

Cheese↗

PubMed2006

Thrombin induces striatal neurotoxicity depending on mitogen-activated protein kinase pathways in vivo.

Intracerebral hemorrhage represents stroke characterized by formation and expansion of hematoma within brain parenchyma. Blood-derived factors released from hematoma are considered to be involved in poor prognosis of this disorder. We previously reported that thrombin, a blood-derived serine protease, induced cytotoxicity in the cerebral cortex and the striatum in organotypic slice cultures, which depended on mitogen-activated protein kinase (MAPK) pathways. Here we investigated the mechanisms of thrombin cytotoxicity in the striatum in vivo. Thrombin microinjected into the striatum of adult rats induced neuronal death and microglial activation around the injection site. Neuronal loss without any sign of nuclear fragmentation was observed as early as 4 h after thrombin injection, which was followed by gradual neuronal death exhibiting nuclear fragmentation. Thrombin-induced damage assessed at 72 h after injection was partially but significantly reduced by concomitant administration of inhibitors of MAPK pathways. Activation of extracellular signal-regulated kinase (ERK) and p38 MAPK in response to thrombin was verified by Western blot analysis. Moreover, phosphorylated ERK and p38 MAPK were localized prominently in reactive microglia, and inhibition of microglial activation by minocycline attenuated thrombin-induced damage, suggesting that reactive microglia were responsible for thrombin-induced neuronal death. Thus, MAPK pathways and microglial activation may serve as therapeutic targets of pathogenic conditions associated with hemorrhagic stroke.

Animals↗

PubMed2006

Anisotropy and corotation of galactic cosmic rays.

The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

Journal Article↗

PubMed2006

Inhibitory effects of ticlopidine on platelet function as assessed by three different methods.

The inhibitory effects of ticlopidine on platelet function were evaluated in 18 healthy male volunteers using three different platelet function tests. Three methods include the recently developed small collagen-beads method, which evaluates the platelet response in whole blood samples under shear stress conditions, the conventional platelet aggregometry and a cone-plate viscometer which measures shear-induced platelet aggregation (SIPA). The latter two methods use platelet-rich plasma as measurement samples instead of whole blood. SIPA was significantly inhibited by the oral intake of ticlopidine. The conventional platelet aggregometry detected significant inhibition of ticlopidine on ADP-induced platelet aggregation. In contrast, ticlopidine moderately inhibited platelet aggregation induced by low concentrations of collagen, but not by high concentrations of collagen. With the collagen-bead column method, ticlopidine significantly inhibited platelet retention rates when the retention rates exceeded 30% prior to ticlopidine uptake. On the other hand, there was no significant inhibition when the original retention rates prior to ticlopidine uptake were below 30%. The three methods all proved useful to evaluate the effect of ticlopidine on platelet function. However, taking into consideration easy procedures, lower costs and use of whole blood samples under shear stress conditions, we suggest the collagen-bead column can serve as an appropriate method for monitoring ticlopidine therapy.

Blood Platelets↗

PubMed2006

Simultaneous production of sphingolipids and ethanol by Kluyveromyces thermotolerans.

Kluyveromyces thermotolerans strain NBRC 1674 was selected for the simultaneous production of sphingolipids and ethanol from beet molasses. The strain gradually synthesized ethanol with fermentation periods and attained a level slightly higher than that of the strain of Saccharomyces cerevisiae usually used for ethanol production. The sphingolipids accumulated in the cells were composed of almost equal amounts of free ceramides and glucosylceramides. The sphingoid bases and fatty acids of the two sphingolipids differed from each other and changed under aerobic and anaerobic growth conditions. Oxygen limitation may cause accumulation of sphinganine by inhibiting sphingolipid desaturases and enhance its proportion in both the sphingolipids.

Anaerobiosis↗

PubMed2005

Immunohistochemical localization of phosphatidylcholine in rat mandibular condylar surface and lower joint cavity by cryotechniques.

The immunolocalization of phospholipids has not yet been clearly demonstrated in temporomandibular joints (TMJs). We have examined the distribution of one of phospholipids, phosphatidyl-choline (PC), in the rat mandibular condylar surface and lower joint cavity. Some fresh resected TMJs with their disks attached were immediately plunged into isopentane-propane cryogen (-193 degrees C). Cryostat sections were cut, mounted on NH3+-coated slides, and fixed with paraformaldehyde (PF). Cryosections were first immunostained with anti-mouse PC antibody (JE-1). Subsequently, they were labeled with immunogold particles following silver enhancing for light microscopic analyses. Some cryosections were subjected to double immunofluoresecence labeling with anti-fibronectin antibody or hyaluronic acid-binding protein in combination with the anti-PC antibody. As an immunocontrol, other cryosections were pretreated with phospholipase A2 before such immunofluorescence labeling. We have confirmed the presence of PC in the lower joint cavity of rat TMJs as well as on the mandibular condylar surface layer, which was colocalized with hyaluronic acid and fibronectin respectively. However, by treatment with phospholipase A2, such immunolabeling for PC was clearly decreased, showing that the PC is a component in the rat in vivo TMJ. These findings suggest that PC, hyaluronic acid and fibronectin may interact each other in the TMJ articular surface areas to play a functional role for lubrication in TMJ.

Animals↗

PubMed2004

Determination of glucosylceramide contents in crop tissues and by-products from their processing.

Glucosylceramides were surveyed in crop tissues and by-products from their processing. Apple pulp contained the highest amount (0.94 mg g(-1)) of glucosylceramide and relatively less sterylglucoside, which is the major contaminant of partially purified glucosylceramide. Glucosylceramide from apple pulp was principally composed of 2-hydroxypalmitic acid as the fatty acid, 4-hydroxy-cis-8-sphingenine as the sphingoid base, and glucose as the hexose, similar to those of commercial preparations isolated from rice bran or wheat germ. Apple pulp may be an alternative source for the commercial production of glucosylceramides.

Agriculture↗

PubMed2004

Observation by an air-shower array in Tibet of the multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun.

We report on the solar diurnal variation of the galactic cosmic-ray intensity observed by the Tibet III air shower array during the period from 1999 to 2003. In the higher-energy event samples (12 and 6.2 TeV), the variations are fairly consistent with the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun, while the variation in the lower-energy event sample (4.0 TeV) is inconsistent with this anisotropy. This suggests an additional anisotropy superposed at the multi-TeV energies, e.g., the solar modulation effect. This is the highest-precision measurement of the Compton-Getting anisotropy ever made.

Journal Article↗

PubMed2004

Antioxidant activity and hypoglycemic effect of ferulic acid in STZ-induced diabetic mice and KK-Ay mice.

Antioxidant activity and biological properties of ferulic acid (FA) are well recognized. This study was designed to estimate the potential utility of FA administered orally at low dosage for improvement of hyperglycemia in diabetes. With this aim we have evaluated the hypoglycemic effect of FA in two type diabetic animal models: (1) streptozotocin (STZ)-induced diabetic mice, a model of insulin-dependent diabetes mellitus (IDDM); (2) KK-Ay mice, a model of non-insulin dependent diabetes mellitus (NIDDM). In addition, we measured the production of thiobarbituric acid-reactive substances (TBARS) in brown adipose tissues of diabetic mice at the end of FA feeding experiment. FA at 0.01% and 0.1% of basal diet showed to suppress significantly blood glucose levels in STZ-induced diabetic mice. In KK-Ay mice 0.05% FA suppressed effectively blood glucose levels. In addition, FA inhibited the lipid peroxidation in brown adipose tissue of diabetic mice. Taken together, these findings suggest that dietary FA may be useful in alleviating oxidative stress and attenuating the hyperglycemic response associated with diabetes.

Animals↗

PubMed2004

Identification of minor fatty acids and various nonmethylene-interrupted diene isomers in mantle, muscle, and viscera of the marine bivalve Megangulus zyonoensis.

To clarify the occurrence of nonmethylene-interrupted (NMI) FA in the marine bivalve Megangulus zyonoensis, methyl esters of unsaturated FA were fractionated according to the degree of their unsaturation by using argentation TLC. Their structures were elucidated by using GC-MS of their FAME and 2-alkenyl-4,4-dimethyloxazoline derivatives. Seventy-two unsaturated FA, including the novel 7,15-21 and 20:4n-1, were identified. The unusual tetraenoic acids 20:4n-4, 20:4n-1, 21:4n-6, and 21:4n-5 were found in M. zyonoensis. This bivalve was extremely rich in the positional isomers of 19:1, 20:2, and 20:3. The distribution of NMI and positional isomers of unusual FA in the bivalve tissues was also discussed.

Animals↗

PubMed2004

Clinical significance and usefulness of quantification of telomerase activity in oral malignant and nonmalignant lesions.

We quantified telomerase activity (TA) in patients with oral and maxillofacial malignant and nonmalignant lesions, and compared it with their clinical status and grade of malignancy. Fifty-two malignant and 52 nonmalignant lesions were analyzed. All malignant lesions were pathologically diagnosed as oral squamous cell carcinoma (OSCC). Normal gingival tissue served as a control. These specimens were obtained by biopsy or surgical resection, and stored at -80 degrees C until use. TA was quantified by a fluorescence-based TRAP method. TA levels ranged from 0.00 to 95.24 (average 33.24)U/microgP in 52 malignant lesions, and from 0.00 to 79.35 (average 11.91)U/microgP in 52 nonmalignant lesions (P < 0.0001). TA was detected in 96.2% of malignant and 65.4% of nonmalignant lesions. There was no relationship between TA levels and clinical stages or YK classification. However, under WHO classification, there were significant differences (P < 0.05) between Grades I and III or II + III. Among nonmalignant lesions, epithelial dysplasia showed a significantly higher TA level than that of oral lichen planus (P < 0.05) and other benign lesions (P < 0.0001). Oral lichen planus also significantly differed from other benign lesions (P < 0.05). These results suggest that TA is related to the histological grade of malignancy, and is also useful as a prognostic predictor for precancerous lesions and conditions.

Acid Phosphatase↗

PubMed2004

Ultrastructural study of upper surface layer in rat mandibular condylar cartilage by quick-freezing method.

The purpose of the present study is to clarify native ultrastructures of upper surface layers of the rat mandibular condylar cartilage in vivo by a quick-freezing method. The mandibular cartilaginous tissues were removed with their articular discs attached without opening the lower joint cavity. The specimens were processed for light microscopy, transmission or scanning electron microscopy. Deep-etching replica membranes were also prepared after the routine quick-freezing method. The upper surface layer was well preserved by the quick-freezing method. The cartilaginous tissues, which were fixed without opening their articular discs, appeared to keep better morphology than those after opening them. The upper surface layer was thicker than the corresponding layer as reported before. It consisted of atypical extracellular matrices with lots of apparently amorphous components, which were distributed over typical collagen fibrils, by conventional electron microscopy. As revealed with the replica membranes, it also consisted of variously sized filaments and tiny granular components localized on the typical collagen fibrils. A pair of stereo-replica electron micrographs three-dimensionally showed compact filaments within the upper surface layer. The quick-freezing method was useful for keeping native ultrastructures of the fragile upper surface layer in the mandibular condylar cartilage, which may be functionally important to facilitate smooth movement of the temporomandibular joint.

Animals↗

PubMed2004

Immunohistochemical study of the upper surface layer in rat mandibular condylar cartilage.

Both hyaluronic acid and fibronectin localizations were examined in the upper surface layer of rat mandibular condylar cartilages by immunohistochemical techniques. Their delicate structure was successfully preserved by preparation procedures of joint condyles with disks. Paraformaldehyde-fixed cartilaginous tissues were cut in a cryostat, and cryosections were analyzed using streptavidin-peroxidase and indirect immunofluorescence methods. Another immunogold method with conventional preparation procedures and a quick-freezing method was performed for their ultrastructural analyses. Both hyaluronic acid-binding protein and anti-fibronectin antibody were used to localize hyaluronic acid and fibronectin in the mandibular condylar cartilage, respectively. Some cryosections were pre-treated with hyaluronidase and chondroitinase before such labeling. The upper surface layer was composed of double laminar structures. One bordered with the cartilage matriceal surface, which was positive for fibronectin. The hyaluronic acid was localized over the fibronectin layer. Therefore, the hyaluronic acid in vivo was bound with fibronectin in the cartilaginous matrix, performing lubrication for the mandibular joint movement.

Animals↗

PubMed2003

Relationship between transcardiac gradient of endothelin-1 and left ventricular remodelling in patients with first anterior myocardial infarction.

Aims To evaluate whether plasma endothelin-1 (ET-1) is extracted or produced through the heart in patients with acute myocardial infarction (AMI), and the relationship between transcardiac extraction of plasma ET-1 and left ventricular (LV) remodelling. Methods and results We measured the plasma level of ET-1 in the aortic root (Ao) and coronary sinus (CS) in 48 consecutive patients, who received successful revascularization and enalapril, for a first anterior AMI. In the acute phase the plasma ET-1 level was significantly higher both in the Ao and the CS compared to the control subjects. However, the plasma ET-1 level was significantly lower in the CS than in the Ao in the acute phase and after 1 month. There were significant correlations between transcardiac extraction of ET-1 in the acute phase and LV ejection fraction and LV end-diastolic volume index (LVEDVI) after 1 month. Stepwise multivariate analysis showed that maximal creatine phosphokinase and transcardiac extraction of plasma ET-1 during the acute phase were independently and positively correlated with the absolute change in LVEDVI after 1 month. Conclusions These results indicate that elevated circulating ET-1 is extracted through the heart in patients with a first anterior AMI and that the extracted ET-1 plays a significant role in modulating post-infarct LV remodelling.

Atrial Natriuretic Factor↗

PubMed2002

Primary cutaneous aspergillosis caused by Aspergillus ustus following reduced-intensity stem cell transplantation.

A 19-year-old woman with myelodysplastic syndrome underwent reduced-intensity stem cell transplantation [RIST: (cladribine 0.11 mg/kg for 6 days, busulfan 4 mg/kg for 2 days, and rabbit antithymocyte globulin)] from her one HLA-mismatched mother. Prophylaxis against graft-versus-host disease (GVHD) was performed with cyclosporine A (CSA) alone. Severe acute GVHD in the skin, gut, and liver developed concurrently with stable engraftment, and methylprednisolone was administered (1-2 mg/kg per day, then pulse therapy with 1 g/day for 3 days) until day 40 of transplant, when a necrotic lesion of 10 mm in diameter appeared on the right cheek. The initial skin biopsy of the affected area showed a nonspecific inflammatory change. Routine X-ray and computed tomography examinations of the sinuses, chest, and abdomen disclosed no particular abnormalities. Despite intensive antibiotic therapy, the lesion rapidly extended to form an ulcer. A second biopsy specimen obtained from the lesion showed massive septa hyphae, suggesting mold infection. Although we immediately started amphotericin B, she died of multiorgan failure on day 68. Postmortem DNA sequence analysis of the specimen using the polymerase chain reaction identified Aspergillus ustus. Although this is an extremely rare complication after transplantation, this case highlights that we should pay more attention to primary cutaneous aspergillosis in severely immunosuppressed patients.

Adult↗

PubMed2002

Suspected delayed immune recovery against cytomegalovirus after reduced-intensity stem cell transplantation using anti-thymocyte globulin.

A reduced-intensity hematopoietic stem cell transplantation (RIST) regimen was developed to induce immunosuppression to facilitate the engraftment of donor cells. However, there have been concerns that the incidence of opportunistic infection may increase after this procedure. To address this problem, we retrospectively analyzed the medical records of 24 RIST recipients who were treated over a recent 16-month period for comparison with 31 recipients of conventional allogeneic transplantation (CST). The RIST regimen consisted of cladribine (0.66 mg/kg), busulfan (8 mg/kg), and rabbit anti-thymocyte globulin (ATG; 5-10 mg/kg). All of the patients received allogeneic peripheral blood stem cells from an HLA-identical or one-locus mismatched related donor. Although the incidence of positive CMV antigenemia was comparable between the two groups (58% vs 68%), RIST patients developed positive antigenemia significantly sooner than did CST patients (P = 0.01) and showed higher initial and maximum antigenemia values (P = 0.026 and P = 0.003, respectively). These findings may suggest that immune recovery against CMV was delayed after our RIST procedure, but this did not directly translate into an increase in clinically significant CMV disease. Early therapeutic intervention with ganciclovir might play a role in preventing the progression of early CMV infection to CMV disease.

Adolescent↗

PubMed2002

The effects of primary thoracic blast injury and morphine on the response to haemorrhage in the anaesthetised rat.

Primary thoracic blast injury causes a triad of bradycardia, hypotension and apnoea mediated in part via a vagal reflex. Blast casualties may also suffer blood loss, and the response to progressive simple haemorrhage is biphasic: an initial tachycardia followed by a vagally mediated reflex bradycardia which can be attenuated by micro opioid agonists. The aims of this study were to determine the effects of thoracic blast injury on the response to subsequent haemorrhage, and the effects of morphine, administered after blast, on the response to blood loss. Male Wistar rats, terminally anaesthetised with alphadolone-alphaxolone (19-21 mg x kg(-1) h(-1) I.V.), were allocated randomly to one of three groups: Group I, sham blast; Group II, thoracic blast; Group III, thoracic blast plus morphine (0.5 mg x kg(-1) I.V. given 5 min after blast). Blast (Groups II and III) resulted in significant (P < 0.05, ANOVA) bradycardia, hypotension and apnoea. Sham blast (Group I) had no effect. Ten minutes later, haemorrhage (40 % of the estimated total blood volume (BV)) in Group I produced a biphasic response comprising a tachycardia followed by a peak bradycardia after the loss of 33 % BV. Arterial blood pressure did not fall significantly until the loss of 13.3 % BV. In Group II the haemorrhage-induced tachycardia was absent and the bradycardia was augmented: peak bradycardia was seen after the loss of 23 % BV. Mean arterial blood pressure (MBP) began to fall as soon as haemorrhage commenced and was significant after the loss of 10 % BV. Morphine (Group III) prevented the haemorrhage-induced bradycardia and delayed the significant fall in MBP until the loss of 30 % BV. It is concluded that the response to thoracic blast injury augments the depressor response to haemorrhage while morphine attenuates this response.

Anesthesia↗

PubMed2001

Relationship between transcardiac extraction of aldosterone and left ventricular remodeling in patients with first acute myocardial infarction: extracting aldosterone through the heart promotes ventricular remodeling after acute myocardial infarction.

OBJECTIVES: The purpose of this study was to evaluate whether plasma aldosterone (ALD) is extracted or produced through the heart in patients with acute myocardial infarction (AMI) and to determine the relationship between transcardiac extraction of plasma ALD and left ventricular (LV) remodeling. BACKGROUND: Although we demonstrated that circulating ALD was extracted through the failing heart and that transcardiac extraction of ALD correlated with LV end-diastolic volume index (LVEDVI) in patients with congestive heart failure, the existence and increase of ALD synthase in the hearts of infarct rats were reported, suggesting cardiac production of ALD in patients with AMI. METHODS: We measured plasma ALD in the aortic root (Ao) and coronary sinus (CS) in 57 consecutive patients who received successful revascularization and enalapril, with first AMI at acute phase and after one month. We also measured plasma procollagen type III aminoterminal peptide (PIIINP) in the CS. RESULTS: Plasma ALD was significantly lower in the CS than it was in the Ao at the acute phase (84.7 +/- 6.3 pg/ml vs. 105.5 +/- 8.0 pg/ml, p < 0.0001). Significant positive correlations exist between the transcardiac gradient of ALD at the acute phase and the LVEDVI at one month. Moreover, the transcardiac gradient of plasma ALD at the acute phase has a significant correlation with plasma PIIINP, a biochemical marker of fibrosis, after one month. Stepwise multivariate analysis showed that transcardiac extraction of plasma ALD at the acute phase had an independent and significant positive relationship with a large LVEDVI after one month. CONCLUSIONS: These results indicate that plasma ALD is extracted through the heart in patients with AMI at the acute phase and that the extracted ALD plays an important role in modulating post-infarct LV remodeling.

Acute Disease↗