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Biomedical subjects

M Ishihara

Publications and source records attributed to M Ishihara.

At least 91 records · Page 5Linked to original sources
PubMed1998

Anti-ulcer effects of antioxidants: effect of probucol.

We investigated the effect of probucol, a lipid-lowering agent with antioxidant properties, on HCl plus ethanol-induced gastric mucosal injury and on the healing of acetic acid-induced gastric ulcers in rats. When the free radical-scavenging activity of probucol was measured by an electron spin resonance technique, the agent (10(-5)-10(-3) M) scavenged both superoxide anions and hydroxyl radicals. Oral administration of probucol (250-1000 mg/kg) dose dependently prevented the HCl plus ethanol-induced gastric mucosal injury and the increase in thiobarbituric acid-reactive substances, an index of lipid peroxidation, in the injured mucosa. Repeated oral administration of probucol (250-1000 mg/kg twice daily) dose dependently accelerated the healing of acetic acid-induced gastric ulcers. In addition, probucol already inhibited the increase in the content of thiobarbituric acid-reactive substances in the ulcerated region before the ulcer-healing effect of this agent was recognized. These results suggest that probucol may partly protect gastric mucosa from acute gastric mucosal injury and promote the healing of chronic gastric ulcers by its antioxidant activity.

Acetic Acid↗
PubMed1998

T lymphopenia in genetically obese rats.

Although obese animals are more susceptible to infection, the underlying causes are not fully known. In this study, long-term measurements were made of lymphocyte subsets in peripheral blood, spleen, and thymus in genetically obese Zucker (fa/fa) rats. Blastogenic response of splenocytes to mitogens was also examined. fa/fa rats developed obesity, hyperlipidemia, and hyperinsulinemia after 5 weeks of age. Flow cytometric analysis revealed that T cells in peripheral blood, spleen, and thymus were all reduced significantly in obese rats after 8 weeks of age compared to nonobese (Fa/-) littermates. All T-cell subsets examined, including CD4+ and CD8+ T cells, were similarly reduced in spleen and thymus as well as in peripheral blood with advance in age. In addition, proliferative responses of splenocytes to mitogens were significantly low in obese rats. These results indicate that long-term obesity may reduce the size of the T-cell pool and impair the responsiveness of splenocytes in rats.

Animals↗
PubMed1998

Rapid data acquisition protocol in ECG-gated myocardial perfusion SPECT with Tc-99m-tetrofosmin.

Into 25 patients with heart disorders, 99mTc-tetrofosmin 555-740 MBq was injected intravenously at rest. After 40 minutes, ECG-gated myocardial perfusion SPECT was performed with a two detector gamma camera VERTEX (ADAC), setting up two detectors to form a 90-degree angle. Sixteen frames per R-R interval were acquired during a 180 degree rotation from the RAO 45 degrees to the LPO 45 degrees. A pair of data sets with standard (SDA) and rapid data acquisition (RDA) protocols was collected. In an SDA protocol, SPECT imaging was performed for 50 sec per step in 5 degree angular steps (total acquisition time; 15 minutes). An RDA protocol was conducted with 12 sec per step, 6 degree angular steps (acquisition time, 3 minutes). LVEF (%) and LVEDV (ml) quantitated automatically with a QGS program showed excellent correlations between two protocols with correlation coefficients of 0.980 (p < 0.01) and 0.983 (p < 0.01), respectively. Subsequently visual assessment of regional wall motion based on a four-point grading system was carried out with a 3-D cine LV display. High complete agreement was gained with 158 (90.3%) out of total 175 segments, so that assessment of the global and regional LV function with the RDA protocol demonstrated high reliability and feasibility.

Electrocardiography↗
PubMed1998

Seroprevalence of anti-Borrelia antibodies among patients with confirmed sarcoidosis in a region of Japan where Lyme borreliosis is endemic.

BACKGROUND: Sarcoidosis is a multisystemic granulomatous disease of unknown etiology, while Lyme borreliosis is a multisystemic disorder caused by Borrelia burgdorferi. The purpose of this study is to evaluate the relationship between sarcoidosis and Lyme borreliosis in a region of Japan where Lyme borreliosis is endemic. METHODS: We determined the seroprevalence of anti-Borrelia burgdorferi antibodies as well as antibodies three Japanese Borrelia strains by enzyme-linked immunosorbent assay and dotblot assay using purified Borrelia-specific proteins in 46 patients with confirmed sarcoidosis and 150 controls (50 disease controls and 100 healthy controls) in Hokkaido, the affected region. RESULTS: Fifteen patients with sarcoidosis (32.6%) tested positive for Borrelia spirochete in both assays, compared with two disease controls (4.0%) and two healthy controls (2.0%). The seroprevalence of anti-Borrelia antibodies in patients with sarcoidosis was much higher in the affected region than in the region in our previous study were Lyme borreliosis is non-endemic. CONCLUSION: In a region where Lyme borreliosis is endemic, Borrelia infection may be partially associated with sarcoidosis.

Antibodies, Bacterial↗
PubMed1998

Structure of neutral branched xylooligosaccharides produced by xylanase from in situ reduced hardwood xylan.

Two neutral oligosaccharides from in situ reduced hardwood xylan were isolated and completely characterized by methylation analysis and 2D NMR spectroscopy (COSY, HOHAHA, HMQC, HMQC-TOCSY, NOESY, and HMBC techniques). The oligosaccharides are the xylotetrasaccharide, 4-O-methyl-alpha-D-glucopyranosyl-(1-->2)-D-xylotriose and the xylopentasaccharide 4-O-methyl-alpha-D-glucopyranosyl-(1-->2)-D-xylotetraose. From reactivities observed with these compounds, the mode of action of beta-xylanase is described.

Carbohydrate Sequence↗
PubMed1998

Reduced serum dehydroepiandrosterone levels in diabetic patients with hyperinsulinaemia.

OBJECTIVE: To elucidate the interaction between insulin and dehydroepi-androsterone (DHEA) concentrations, we evaluated serum DHEA and DHEA-sulphate (DHEA-S) levels in diabetic patients with hyperinsulinaemia. PATIENTS AND DESIGN: Twenty-four subjects with non-insulin dependent diabetes mellitus, 12 hyperinsulinaemic subjects (fasting serum insulin concentrations > or = 10 mU/ml (71.8 pmol/l)) and 12 non-hyperinsulinaemic subjects, and 10 normal control subjects were studied. Serum DHEA, DHEA-S, cortisol and ACTH levels were investigated in these subjects. Moreover, their serum DHEA levels were compared during hyperinsulinaemic-euglycaemic clamp and after ACTH stimulation. MEASUREMENTS: Serum insulin, cortisol, ACTH, DHEA and DHEA-S concentrations were evaluated by RIA. Serum glucose was determined by the glucose oxidase method. RESULTS: Diabetic patients with hyperinsulinaemia showed significantly lower levels of serum DHEA and DHEA-S than controls. After ACTH stimulation, these patients also showed significantly lower DHEA levels. During the hyperinsulinaemic-euglycaemic clamp, serum DHEA concentrations of diabetic patients with hyperinsulinaemia remained low and did not decline further, although those of control subjects and non-hyperinsulinaemic diabetic patients showed a significant decline of serum DHEA levels. Even after ACTH stimulation during the clamp, serum DHEA in hyperinsulinaemic patients was still significantly lower than in controls. CONCLUSIONS: In diabetic patients with hyperinsulinaemia, baseline DHEA levels are chronically and maximally suppressed compared to control subjects and non-hyperinsulinaemic diabetic patients, and thus not decreased further by exogenous insulin infusion during hyperinsulinaemic-euglycaemic clamp.

Adrenocorticotropic Hormone↗
PubMed1998

Single-shot diffusion-weighted echo-planar imaging of normal and cirrhotic livers using a phased-array multicoil.

Single-shot spin-echo diffusion-weighted echo-planar imaging using a phased-array multicoil was performed to distinguish between normal and cirrhotic livers. Sets of 6 images with different b-values were acquired with breath-holding. Significant differences were observed between controls and cirrhosis cases in the signal ratios when the b-value was 383 s/mm2, and apparent diffusion coefficients.

Adult↗
PubMed1998

Disaccharide analysis of heparin and heparan sulfate using deaminative cleavage with nitrous acid and subsequent labeling with paranitrophenyl hydrazine.

Compositional analyses of heparin (Hep) and heparan sulfate (HS) have been undertaken with disaccharide units obtained by either enzymatic digestion with heparitinases or hydrazinolysis/deamination reaction of polysaccharides. Unsaturated disaccharide units generated by the enzymatic method are detectable on HPLC with a uv detector recording absorbance at 230 nm. On the other hand, disaccharide units generated by the chemical method possess a component of 2,5-anhydromannose (AnMan) bearing aldehyde groups in addition to intact iduronic acid (IdoA) or glucuronic acid (GlcA). The aldehyde groups of the disaccharide units are usually reduced with sodium borotritide, and detected by radiochromatography. Both of them, however, involve inevitable experimental problems, such as the use of costly enzymes and radioisotopes. In the present study, we have established a novel composition analysis system for Hep and HS essentially based on the chemical method. After hydrazinolysis/deamination treatment of Hep and HS, the aldehyde groups of AnMan in the disaccharide units generated were coupled with paranitrophenyl (PNP-) hydrazine instead of reduction with sodium borotritide, AnMan-CH=N-NH-PNP (AnMan-PNP) being formed. Then, the PNP-labeled disaccharides were pre-treated on a SepPak C-18 cartridge column, and subsequently separated and detected on ion-pairing reversed-phase HPLC with a detector recording absorbance at 390 nm. With the present system, the order of elution was GlcA-AnMan-PNP (GM), IdoA-AnMan-PNP (IM), IdoA(2S)-AnMan-PNP (ISM), IdoA-AnMan(6S)-PNP (IMS), and IdoA(2S)-AnMan(6S)-PNP (ISMS). As an application, the disaccharide compositions of heparin from bovine intestine and heparan sulfate from bovine kidney were analyzed by the present method, and the results were comparable to those obtained by a well-established enzymatic method. The present compositional analysis was demonstrated to be reliable and economical.

Acetylation↗
PubMed1998

Transcranial magnetic stimulation of the oculomotor and abducens nerves: determining the site of excitation in the cat.

The authors have attempted to stimulate the feline oculomotor and abducens nerves using a magnetic coil (MC) and to determine the optimal reliable MC position for eliciting motor evoked potentials. The authors have also determined the site of excitation to analyze the validity and potential advantages of this technique as a means of neurophysiologically studying the oculomotor and abducens nerves. The potentials of both of these muscles are evoked by MC placed to be symmetrical to the line connecting the vertex and the center of the eyeball on the side being examined, as the coil center corresponds to the midpoint of this line. The latencies of the motor responses of the superior rectus and lateral rectus were 1.08 +/- 0.22 and 1.02 +/- 0.21 msec, respectively, suggesting that magnetic stimulation excites both the oculomotor and the abducens nerve at the superior orbital fissure.

Abducens Nerve↗
PubMed1998

The discrepancy between 99Tcm-ECD dynamic and static SPET images in patients with ischaemic lesions corresponds to reduced vasoreactivity to acetazolamide.

We evaluated 99Tcm-N,N'-(1,2-ethylenediyl)bis-L-cysteine diethyl ester (99Tcm-ECD) dynamic and static SPET (single photon emission tomographic) images to examine 99Tcm-ECD kinetics under ischaemic cerebrovascular conditions. In 20 patients who showed arterial occlusion on magnetic resonance angiography, dynamic (0-10 min) and static (15-35 min) SPET images were acquired after the intravenous administration of 99Tcm-ECD. Thirteen of the patients had focal perfusion deficits that were more evident on the dynamic than on the static images; the other seven showed no such discrepancy. In those patients with a mismatch between the dynamic and static images, the extent corresponded to reduced vaso-reactivity to acetazolamide. Based on quantitative analysis of the ratio of tracer uptake in affected to that in unaffected areas, the patients with discrepant findings showed significantly different ratios on the dynamic and static images, whereas those with no such mismatch did not. Our results suggest that dynamic 99Tcm-ECD images provide circulatory information and that static images reflect a filling-in phenomenon of ECD metabolites in ischaemic lesions. 99Tcm-ECD dynamic and static SPET images offer an alternative method of detecting mild perfusion deficits without the need for acetazolamide challenge.

Acetazolamide↗
PubMed1998

Major histocompatibility complex class II alleles in an Uygur population in the Silk Route of Northwest China.

HLA class II (DRB1, DQA1, DQB1 and DPB1) genotyping was performed in 57 unrelated Uygur individuals inhabiting the northwestern China area by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Among 98 DRB1 alleles tested, 23 alleles were detected, and DRB1*0701 (16.7%) and DRB1*0301 (14.0%) were the most and the second most common alleles, respectively. In 8 DQA1 alleles detected, DQA1*05 (26.3%), DQA1*03 (21.9%) and DQA1*0201 (21.1%) were very frequent. Of 21 DQB1 alleles tested, 13 were observed. Among them, DQB1*02 was highly predominant with the gene frequency of 32.5%. Of 46 DPB1 alleles tested, 15 were detected, among which DPB1*0401 (31.6%) was the most frequent. Two haplotypes predominate clearly; DRB1*0701-DQA1*0201-DQB1*02 (15.5%) and DRB1*0301-DQA1*05-DQB1*02 (12.6%). The dendrogram constructed by the neighbour-joining (NJ) method based on the allele frequencies of the DRB1, DQA1, DQB1 and DPB1 genes of 13 representative populations all over the world suggested that Uygur belonged to the Asian group and lay at the closest genetic distance to a Kazak population inhabiting the same area.

Alleles↗
PubMed1998

Extended HLA haplotypes in Japanese homozygous typing cells.

We have defined extended HLA haplotypes including the HLA class II genes, the non-HLA genes such as TAP1, TAP2 and LMP2, and the (CTG)n microsatellite repeats within the NOTCH4 gene between DRA and 21OH in 33 Japanese HLA homozygous typing cells (HTC). These conserved haplotypes characterized by unique linkage might be maintained as a result of functional co-operation among them in the antigen presentation pathway. These HTCs can be served as an original and ethnic-specific standard panel, providing useful genetic markers in haplotypic diversity, disease association, and anthropology studies.

HLA Antigens↗
PubMed1998

Staining of eccrine and apocrine neoplasms and metastatic adenocarcinoma with IKH-4, a monoclonal antibody specific for the eccrine gland.

The histogenesis of apocrine and eccrine neoplasms has always interested dermatopathologists. In addition, the histologic differential diagnosis of eccrine carcinoma from metastatic adenocarcinoma is of practical importance. We describe a novel monoclonal antibody IKH-4 which stains the eccrine secretory coil, but not the apocrine secretory segment. Positive staining was observed in eccrine hidradenoma, eccrine poroma, eccrine spiradenoma, papillary eccrine adenoma, eccrine hidrocystoma, syringoma, eccrine carcinoma, and in 1 case of syringocystadenoma papilliferum. Negative staining was observed in apocrine adenocarcinoma, hidradenoma papilliferum, erosive adenomatosis of the nipple, and primary and metastatic adenocarcinomas. IKH-4 antibody was useful in differentiating eccrine from apocrine neoplasms and in differentiating eccrine carcinoma from metastatic adenocarcinomas.

Adenocarcinoma↗
PubMed1998

Delayed vagal withdrawal slows circulatory but not oxygen uptake responses at work increase.

The effect of delayed vagal activity withdrawal on cardiorespiratory responses at an increase in workload was examined. Eleven volunteers (21 +/- 3 yr, 66 +/- 4 kg) performed cycle ergometer exercise at a work rate corresponding to 80% of ventilatory threshold after 3 min of unloaded cycling. Facial stimulation was given by applying a vinyl bag filled with cold water (3-5 degrees C) to the face 1 min before to 1 min after the increase in workload (S2 trial) or no stimulation was given (Nr trial). Oxygen uptake (VO2), heart rate (HR), and cardiac output (Q) were continuously recorded in four transitions for each trial. Data were averaged for each subject and trial. Mean response time (MRT, sum of delay and time constant) was calculated with monoexponential fitting. Facial stimulation induced acute bradycardia (-10 +/- 5 beats/min in S2 trial). The MRT of HR and Q was significantly longer in the S2 trials (46 +/- 35 and 37 +/- 23 s) than in the Nr trials (26 +/- 18 and 28 +/- 19 s, respectively), but no significant change in VO2 MRT was shown (36 +/- vs. 38 +/- 12 s). These findings suggest that increased vagal activity delays the central circulatory responses, which does not alter the VO2 kinetics at the onset of stepwise increase in workload. The maintenance of VO2 kinetics during acute bradycardia may either reflect the fact that some intramuscular processes (such as oxidative enzyme inertia) limit VO2 kinetics or alternatively that increased sympathetic vasoconstriction at some remote site defends exercising muscle blood flow.

Coronary Circulation↗
PubMed1998

Anti-ulcer effects of antioxidants, quercetin, alpha-tocopherol, nifedipine and tetracycline in rats.

When free radical-scavenging activities of quercetin, alpha-tocopherol, nifedipine and tetracycline were measured by an electron spin resonance technique, all test compounds (10(-5) to 10(-3) M) scavenged both superoxide anions and hydroxyl radicals. The oral administration of quercetin (50 and 100 mg/kg), alpha-tocopherol (8 and 16 mg/kg), nifedipine (20 and 40 mg/kg) or tetracycline (10 and 20 mg/kg) markedly prevented the HCl plus ethanol-induced gastric mucosal injury and the increase in the content of thiobarbituric acid-reactive substances in the injured mucosa in rats. In addition, quercetin (25, 50 and 100 mg/kg), alpha-tocopherol (4, 8 and 16 mg/kg), nifedipine (10, 20 and 40 mg/kg) and tetracycline (5, 10 and 20 mg/kg), given orally, twice daily for 14 consecutive days from the day after acetic acid injection, dose-dependently promoted the ulcer healing and inhibited the increase in the content of thiobarbituric acid-reactive substances in the ulcerated mucosa. These results indicate that quercetin, alpha-tocopherol, nifedipine and tetracycline possess gastric cytoprotective and gastric ulcer healing-promoting actions. In addition, the free radical-scavenging properties of these compounds may be partly related to their anti-ulcer effects.

Acetic Acid↗
PubMed1998

Plasma cell granuloma extending from the extracranial to the intracranial space associated with Epstein-Barr virus infection.

A 70-year-old male presented with a plasma cell granuloma extending from the extracranial to the intracranial space. Findings of preoperative magnetic resonance imaging and intraoperative observation indicated that the lesion extended from the temporal muscle to the subarachnoid space, penetrating the frontal bone. The subarachnoid lesion was composed of neutrophils indicating the presence of acute or subacute inflammation. The final diagnosis of the resected tumor was plasma cell granuloma. High levels of antibodies against Epstein-Barr (EB) virus in the cerebrospinal fluid and the immunohistochemical demonstration of EB nuclear antigens in the plasma cell granuloma suggested that EB virus infection was associated with the development of plasma cell granuloma in this patient.

Aged↗
PubMed1998

[Clinical usefulness of "optimal threshold setting plan" for reconstruction of three-dimensional CT imaging: preliminary clinical study on hepatic tumors and hepatic parenchymal disease].

Clinical application of three-dimensional CT (3D-CT) angiography using the volumetric acquisition capabilities inherent in spiral CT has provided 3D-CT images of vascular structures as well as visceral organs. However, the standard method for deciding the threshold, which is an important process for defining regions of interest, has not yet been established. The setting of an inappropriate threshold may result in reconstruction of a 3D-CT image, leading to misdiagnosis. To simplify the determination of the optimal threshold in a way consistent with the purpose of reconstructing a 3D-CT image, we developed an Optimal Threshold Setting Plan (OPT Plan). With this method, an optimal 3D-CT image could be selected from among those multiple 3D-CT images that were reconstructed on the basis of the multiple thresholds input in advance by referring to attenuation values in both the hepatic lesion and its background on two-dimensional CT images. Clinical usefulness of the OPT Plan for the reconstruction of 3D-CT images was evaluated in 10 patients with hepatic tumors and hepatic parenchymal disease. We obtained 13 3D-CT images (on average) with threshold changes every 5 Hounsfield units, with a mean reconstruction time of 2 minutes 49 seconds, and easily selected an adequate 3D-CT image. Based upon this preliminary experience, the OPT Plan may resolve the difficulty encountered in the setting of thresholds for achieving 3D-CT images, and is considered to be useful for three-dimensional qualitative evaluation of hepatic lesions and hepatic parenchymal disease.

Adult↗