Biomedical subjects

Hiroyuki Okada

Publications and source records attributed to Hiroyuki Okada.

67 records · Page 4Linked to original sources

PubMed2002

Effects of chlorpromazine, pentoxifylline and dexamethasone on mRNA expression of lipopolysaccharide-induced inflammatory cytokines in bovine peripheral blood mononuclear cells.

The effects of chlorpromazine (CPZ), pentoxifylline (PTX) and dexamethasone (DEX) on mRNA expression of lipopolysaccharide (LPS)-induced proinflammatory cytokines were examined in bovine peripheral blood mononuclear cells (PBMCs) in vitro. The expression of inflammatory cytokine mRNAs was analyzed by RT-PCR and Southern blot hybridization in bovine PBMCs. CPZ and DEX decreased the expression of cytokine mRNA (such as interleukin-1 beta and tumor necrosis factor-alpha) after stimulation with LPS in a dose-dependent manner. However, pretreatment with PTX had no inhibitory effect on the mRNA expression of proinflammatory cytokines. These results indicated that pretreatment with CPZ and DEX might be effective to reduce the production of LPS-induced inflammatory cytokines in bovine PBMCs in vitro.

Animals↗

PubMed2002

Identification of a target antigen recognized by a mouse monoclonal antibody to the bile canalicular surface of rat hepatocytes with a random phage display library.

We developed a monoclonal antibody (MoAb) (clone 5E8) against an antigen on the bile canalicular membrane of rat hepatocyte. By immunoblotting, MoAb 5E8 detected a band of 110 kD. In this study, we used the phage display technique to identify the target antigen recognized by MoAb 5E8. We screened a random phage display library expressing 12-mer peptide sequences and identified a peptide sequence, FHFNPYTGHPLT, as an epitope. We compared this peptide sequence with those of dipeptidyl peptidase IV (DPP IV, E.C.3.4.14.5) and Cell-CAM105, which proteins were located by a database search based on the information of tissue localization and approximate molecular weight of the MoAb 5E8 antigen, and sequence similarity with a region in DPP IV (amino acids 225-233) but not with Cell-CAM105 was found. In addition, we immunohistochemically stained various tissues (liver, small intestine, and kidney) of Japanese Fischer 344 rats, known to be deficient for DPP IV, with MoAb 5E8 and showed that the expression of MoAb 5E8 antigen was negligible or weak. In contrast, tissues sampled from the same organs of Sprague-Dawley rats, known to express DPP IV, were positively stained. These findings suggest that the antigen recognized by MoAb 5E8 is DDPIV and its major epitope is located in amino acids at positions 225-233.

Amino Acid Sequence↗

PubMed2002

Improvements in the measurement of stool decay-accelerating factor in the detection of colorectal cancer.

We have previously developed an enzyme-linked immunosorbent assay (ELISA) to measure stool decay-accelerating factor (DAF) and found that stool DAF concentrations were significantly elevated in patients with colorectal cancer, suggesting that the measurement of stool DAF may be valuable for the detection of colorectal cancer. In order to refine the assay for the measurement of stool DAF, we investigated 1) effects of centrifugation of stool samples, 2) effects of detergents, and 3) adequate combination of various anti-DAF monoclonal antibodies for the ELISA system using only monoclonal antibodies. We found that high-speed centrifugation could be omitted and that only the removal of large undigested food residues by centrifugation of short duration in a low-speed benchtop microcentrifuge sufficed to adequately prepare the stool samples. Addition of 2 detergents, octyl beta-glucoside and sodium deoxycholate, known to solubilize glycosyl-phosphatidylinositol-anchored proteins such as DAF, did not influence stool DAF values. By using 2 mouse anti-DAF monoclonal antibodies (clone 4F11 and 1C6), we were able to achieve a stable ELISA for the measurement of stool DAF using a uniform source of antibodies. The results should allow us to consistently apply the DAF assay for routine use in the detection of colorectal cancer.

Aged↗

PubMed2002

Anti-asialoglycoprotein receptor autoantibodies, detected by a capture-immunoassay, are associated with autoimmune liver diseases.

In autoimmune chronic active hepatitis (AIH) and primary biliary cirrhosis (PBC), various autoantibodies including anti-asialoglycoprotein receptor (ASGPR) antibodies have been found in patients' sera. We have previously developed a mouse monoclonal antibody against rat and human ASGPR. In this study, we developed a capture enzyme-linked immunosorbent assay (ELISA) for detection of anti-ASGPR antibodies using this monoclonal antibody and investigated the occurrence of anti-ASGPR antibodies in the sera of patients with various liver diseases. Serum samples were obtained from 123 patients with various liver diseases, including 21 patients with AIH and 40 patients with PBC. In this capture ELISA, the target antigen in the crude rat liver membrane extracts was captured on the ELISA wells by the ASGPR-specific mouse monoclonal antibody. Thus, the cumbersome process of antigen purification was rendered unnecessary. Using this capture ELISA, we detected the anti-ASGPR antibody in 67% of the patients with AIH, in 100% of the patients with PBC, and in 57% of the patients with acute hepatitis type A. However, the anti-ASGPR antibody was rarely detected in patients with other liver diseases such as primary sclerosing cholangitis and obstructive jaundice. Our findings suggest that this capture ELISA would be useful for the detection of anti-ASGPR antibodies in autoimmune liver diseases.

Adolescent↗

PubMed2002

Development of syngeneic monoclonal anti-idiotype antibodies to mouse monoclonal anti-asialoglycoprotein receptor antibody.

Anti-idiotype antibodies (Ab2) play an important role in the homeostasis of immune responses and are related to the development and the disease activity of certain autoimmune diseases. The asialoglycoprotein receptor (ASGPR) is considered one of the target antigens in the pathogenesis of autoimmune chronic active hepatitis (AIH). We previously developed a mouse monoclonal antibody (clone 8D7) which recognizes rat and human ASGPR. In this study, to help investigate the anti-ASGPR antibody-anti-idiotype antibody network in patients with AIH, we developed a syngeneic mouse monoclonal Ab2 to the 8D7 anti-ASGPR antibody (Ab1). One clone, designated as 3C8, tested positive for specific reactivity to 8D7-Ab1 and did not bind to other irrelevant immunoglobulins. By competitive inhibition assays, the binding of 8D7-Ab1 to liver membrane extracts, i.e., the crude antigen preparation, was inhibited by 3C8-Ab2 in a dose-dependent manner, and the binding of 8D7-Ab1 to 3C8-Ab2 was inhibited by the liver membrane extracts. In the immunohistochemical analysis, 3C8-Ab2 blocked the specific staining of sinusoidal margins of rat hepatocytes by 8D7-Ab1. These results suggest that 3C8 anti-idiotype antibody recognizes the specific idiotypic determinants within the antigen-binding site of 8D7-Ab1.

Animals↗

PubMed2002

Primary intraosseous carcinoma arising from an odontogenic cyst: a case report and review of the Japanese cases.

A rare case of primary intraosseous carcinoma (PIOC) arising from an odontogenic cyst in a 58-year-old man is reported. Clinical and radiological examinations revealed an odontogenic cyst of the maxilla. Histopathologically, the lesion was composed of a cyst with a parakeratotic epithelial lining and well-differentiated squamous cell carcinoma, showing continuity between them without a connection to the oral mucosa. Twenty-eight well-documented Japanese cases of Type-1 PIOC, including the present case, were reviewed. The mean age of the 28 patients was 56.1 years, and the male to female ratio was 1.8:1.0. Compared with currently reported Japanese reviews of Type-3, foreign Type-1 and Type-3, there were no significant differences in mean patient age and sexual predominance, and no racial difference. The pathogenesis of Type-1 PIOC is also discussed.

Carcinoma, Squamous Cell↗

PubMed2002

Imprint cytology of ameloblastoma.

To reveal the characteristic features of the imprint cytology of ameloblastomas, we compared these features with the histopathological features of the same specimens. Twenty-five cases, histopathologically diagnosed as ameloblastoma, were used. Three cell types were recognized: small squamous epithelial cells which were polyhedral or spindle-shaped with some projections; naked cells with poorly defined cytoplasm showing tubular and palisade patterns in some areas; and large squamous epithelial cells with extensive wrinkled cytoplasm. Naked cells and small squamous epithelial cells were thought to correspond to the histopathological classifications of cuboidal to columnar cells, and polyhedral or spindle cells respectively. Large squamous epithelial cells were thought to be acanthomatous cells showing squamous metaplasia. Imprint cytology had characteristic advantages compared to fine needle aspiration cytology, and clearly reflected the histopathology of the lesions. Knowledge of the characteristic features of the cells observed in imprint cytology is important when undertaking cytodiagnosis using fine needle aspiration.

Adolescent↗

PubMed2002

[Effect of antiulcer agents on the urea breath test--Comparison between rebamipide and ecabet sodium].

In this study, we assessed whether standard doses of antiulcer drugs rebamipide, and ecabet sodium influence the accuracy of the urea breath test (UBT). Without medication, values of UBT estimated with nondispersive isotope-selective infrared spectrometry did not significantly change during follow-up (average 4.4 months). Then, we randomized 21 H. pylori-positive patients without serious disease to receive either rebamipide or ecabet sodium for 28 days. UBT was performed at baseline, on day 14, on day 28, and 2 weeks after cessation of drugs. On day 14, the median value of UBT declined significantly (p = 0.0113) compared to baseline with ecabet sodium but not with rebamipide. This caused a false-negative result of UBT in one of 11 patients who received ecabet sodium. The decline of UBT resolved 2 weeks after drug cessation. In addition, we performed a crossover study in 11 H. pylori-positive volunteers with these drugs, and ecabet sodium but not rebamipide significantly reduced UBT values (p = 0.0058). These findings indicate that ecabet sodium adversely influences the accuracy of UBT and that the withdrawal of this drug before testing appears to be necessary to avoid false-negative results.

Abietanes↗

PubMed2002

Neural substrates of human facial expression of pleasant emotion induced by comic films: a PET Study.

Laughter or smile is one of the emotional expressions of pleasantness with characteristic contraction of the facial muscles, of which the neural substrate remains to be explored. This currently described study is the first to investigate the generation of human facial expression of pleasant emotion using positron emission tomography and H(2)(15)O. Regional cerebral blood flow (rCBF) during laughter/smile induced by visual comics and the magnitude of laughter/smile indicated significant correlation in the bilateral supplementary motor area (SMA) and left putamen (P < 0.05, corrected), but no correlation in the primary motor area (M1). In the voluntary facial movement, significant correlation between rCBF and the magnitude of EMG was found in the face area of bilateral M1 and the SMA (P < 0.001, uncorrected). Laughter/smile, as opposed to voluntary movement, activated the visual association areas, left anterior temporal cortex, left uncus, and orbitofrontal and medial prefrontal cortices (P < 0.05, corrected), whereas voluntary facial movement generated by mimicking a laughing/smiling face activated the face area of the left M1 and bilateral SMA, compared with laughter/smile (P < 0.05, corrected). We demonstrated distinct neural substrates of emotional and volitional facial expression and defined cognitive and experiential processes of a pleasant emotion, laughter/smile.

Adult↗

PubMedDate not supplied

Mapping novel nouns and verbs onto dynamic action events: are verb meanings easier to learn than noun meanings for Japanese children?

The present research examined how 3- and 5-year-old Japanese children map novel nouns and verbs onto dynamic action events and generalize them to new instances. Studies 1 to 3 demonstrated that although both 3- and 5-year-olds were able to map novel nouns onto novel objects, only 5-year-olds could generalize verbs solely on the basis of the sameness of the action. Study 4 showed that the difficulty young children experience in learning verbs lies mainly in mapping the appropriate element to a verb rather than in encoding and remembering an action itself. The results of this research are related to a long-debated issue of whether noun learning is privileged over verb learning.

Child, Preschool↗

PubMedDate not supplied

Outcome of patients with inconsistent results from 13C-urea breath test and bacterial culture at the time of assessment of Helicobacter pylori eradication therapy in Japan.

BACKGROUND/AIMS: At the assessment of eradication therapy of Helicobacter pylori, the results of 13C-urea breath test and other methods such as bacterial culture are occasionally inconsistent. In this study, we examined the outcomes of inconsistent results. METHODOLOGY: Four hundred and four patients with peptic ulcer who were H. pylori-positive and who had completed eradication therapy were studied. Bacterial culture, rapid urease tests and 13C-urea breath test were performed between one and three months after the end of the therapy. The cut-off value for the 13C-urea breath test used originally in this study was 2.5 per mil. We investigated the outcome of inconsistent results by following up the patients every 6 to 12 months. RESULTS: At the initial assessment of eradication therapy, we observed inconsistent results with bacterial culture and 13C-urea breath test in 43 of 404 patients. Most of them (40 of 43) were culture-negative but urea breath test-positive, and the majority became negative for both tests. Based on the follow-up results, the optimum value for 13C-urea breath test at the assessment of eradication therapy was found to be 3.5 per mil. CONCLUSIONS: We found that outcomes of inconsistent results were variable, indicating the importance of the follow-up of patients after eradication therapy of H. pylori.

Breath Tests↗

PubMedDate not supplied

H. pylori decreases gastric mucin synthesis via inhibition of galactosyltransferase.

BACKGROUND/AIMS: Alterations of gastric mucin have been postulated as important pathogenic properties of Helicobacter pylori. In this study, we investigated gastric mucin synthesis in H. pylori-infected gastric mucosa by measuring UDP-galactosyltransferase activity, a key enzyme for the synthesis of mucin, and the amount of intracellular mucin in the gastric mucosa. METHODOLOGY: Gastric biopsy specimens were obtained from thirty-seven patients (20 H. pylori-positive and 17 H. pylori-negative). UDP-galactosyltransferase activity of the biopsy specimens was measured by an assay system we had developed, using a peanut agglutinin lectin. The amount of intracellular mucin in the gastric epithelial cells was analyzed by measuring the cells' periodic acid-Schiff-alcian blue staining-positive substances. RESULTS: UDP-galactosyltransferase activities in the antral mucosa, but not in the body mucosa, of H. pylori-positive patients were significantly lower than those of H. pylori-negative patients (p < 0.05). The amount of intracellular mucin in antral epithelial cells of H. pylori-positive patients was significantly lower than that of H. pylori-negative patients (p < 0.01). CONCLUSIONS: These findings suggest that H. pylori infection decreases gastric mucin synthesis via inhibition of UDP-galactosyltransferase. This effect may impair the gastric mucosal barrier and contribute to the mucosal injury induced by H. pylori infection.

Adult↗

PubMedDate not supplied

Trabecular bone response to titanium implants with a thin carbonate-containing apatite coating applied using the molecular precursor method.

PURPOSE: The influence of thin carbonate-containing apatite (CA) coating on the trabecular bone response to titanium implants was investigated. MATERIALS AND METHODS: Thin CA coatings were deposited by a new method known as the molecular precursor method. Using a precursor solution composed of an EDTA-calcium complex, a CA film was deposited on the titanium surfaces. Uncoated and CA-coated titanium were placed in the trabecular bone of the left and right femoral condyles of 16 rabbits. After implantation periods of 2, 4, 8, and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. RESULTS: Histologic evaluation revealed new bone formation around the uncoated and CA-coated implant surfaces after only 4 weeks of implantation. After 12 weeks, mature trabecular bone surrounded all implants. At 4 and 8 weeks of implantation, no difference existed in bone contact between uncoated and CA-coated implants. After 12 weeks of implantation, the CA-coated implant group showed a significantly higher percentage of bone contact than the uncoated implant group. DISCUSSION AND CONCLUSION: The present study demonstrated that thin CA coatings applied using the molecular precursor method showed greater bone-to-implant contact during the healing phase than uncoated controls. The results were similar to those observed with implants with calcium phosphate coatings deposited with a physical vapor deposition technique.

Animals↗