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Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 91 records · Page 5Linked to original sources

A phylogenetic hypothesis for the distribution of two genotypes of the pig tapeworm Taenia solium worldwide.

Genetic polymorphism was determined among 13 isolates of Taenia solium from various regions using PCR-amplified sequences of 2 mitochondrial genes: cytochrome c oxidase subunit 1 and cytochrome b. The 2 phylogenies obtained were similar to each other regardless of the genes examined. The isolates from Asia (China, Thailand, Irian Jaya and India) formed a single cluster, whereas the isolates from Latin America (Mexico, Peru, Ecuador, Bolivia and Brazil) combined with those from Africa (Tanzania, Mozambique and Cameroon) to form an additional cluster. These results and historical data of swine domestication, distribution of pigs and colonization suggest that T. solium was introduced recently into Latin America and Africa from different regions of Europe during the colonial age, which started 500 years ago, and that the tapeworm of another origin independently spread in Asian countries.

Animals↗

A histomorphometric analysis on bone dynamics in denture supporting tissue under continuous pressure.

The purpose of this study was to investigate bone dynamics under a denture base, in relation to the intensity of continuous pressure exerted through it to the denture supporting tissue. Two hundred and fifty male rats of Wistar strain were divided into five groups, four of which wore experimental dentures to load continuous pressure of 0.0, 1.0, 10.0 or 20.0 kPa to the molar region of the hard palate. The fifth group was the non-denture-wearing group. Fluorescent labelled palatal bone tissue was stained with Villanueva bone stain and was prepared for the undecalcified grinding section. In the 0.0 kPa group whose mucosa was covered with denture base, although no bone resorption was observed, bone formation was inhibited up to 4 weeks after the denture insertion. Bone dynamics in the 1.0 kPa group was similar to those in the 0.0 kPa group. In the 10.0 and 20.0 kPa groups, bone resorption was observed until 3 and 2 weeks after the denture insertion, and the amount of bone resorption (AoBR) was 24 +/- 17 and 35 +/- 21 lm, respectively. After bone resorption in these groups, although osteoid formation increased earlier than 0.0 kPa group, mineralization showed a similar time course with 0.0 kPa group. In conclusion, bone dynamics under a denture base caused by continuous pressure exerted through it was revealed to show a time course depending on the intensity of the initial pressure. Amount of bone resorption was also revealed to correspond to the intensity of the initial pressure. Bone formation following bone resorption did not cause equivalent recovery of the bone surface level to the level observed in the case without bone resorption.

Acrylic Resins↗

Borna disease in a dog in Japan.

Borna disease (BD) was diagnosed in a 3-year-old male Welsh corgi suffering from a severe and acute progressive disorder of the central nervous system. Histopathologically, neuronal lesions were characterized by a non-suppurative encephalomyelitis dominated by large perivascular cuffs consisting of lymphocytes, macrophages and plasma cells; also present were inflammatory cell infiltrates in the neural parenchyma, neuronophagia and focal gliosis. Strong immunolabelling with BD virus (BDV) p40 antibody was diffusely distributed in the cytoplasm of small and large neurons in areas of the brain with and without inflammatory changes, and also in the spinal cord. Positive hybridization signals with BDV p40 sense and antisense riboprobes were seen in the nucleus and cytoplasm of the neurons throughout the whole brain and spinal cord. BDV p24 RNA in formalin-fixed brain tissue was detected by reverse transcriptase (RT)-nested polymerase chain reaction (PCR). BDV p24 RNA-positive signals were detected in the temporal lobe. This is the first report of spontaneous canine BD in Japan.

Animals↗

Detection of matrix metalloproteinases in canine mammary tumours: analysis by immunohistochemistry and zymography.

Expression of matrix metalloproteinases (MMPs) was examined immunohistochemically (MMP-9 and -2) and by gelatin zymography (MMP-9) in 12 benign and 12 malignant canine mammary tumours. In nine of 12 benign tumours, weak expression of MMP-9 was demonstrated immunohistochemically in the cytoplasm of neoplastic cells. In the remaining three benign tumours (mixed or complex) MMP-9 expression was observed in the neoplastic luminal epithelial cells and myoepithelial cells in some areas. The neoplastic luminal epithelial cells in 12 malignant tumours reacted strongly for MMP-9. MMP-2 immunolabelling was observed in both benign and malignant tumour tissues, but was stronger in the latter. Zymography and densitometry showed that expression of MMP-9 was higher in the benign mammary tumours than in normal canine mammary tissues, but highest in the malignant mammary tumours. In benign and malignant canine mammary tumours, the zymography and densitometry results for MMP-9 accorded well with the immunohistochemical results obtained with anti-human MMP-9 monoclonal antibody.

Adenocarcinoma↗

Comparison of insulinotrophic actions of nateglinide with glibenclamide dissociated from absorption in conscious dogs.

Nateglinide is more rapidly absorbed than glibenclamide. Therefore, the different absorption kinetics of both drugs were eliminated by intraportal administration in conscious fasted dogs. The plasma insulin profiles were compared under similar kinetic changes in plasma drug concentrations. After a priming dose of nateglinide (1 mg/kg. 5 min) or glibenclamide (40 microg/kg. 5 min), plasma drug concentrations reached a peak at 4 minutes (nateglinide, 80 +/- 5 micromol/L, n = 6 and glibenclamide, 263 +/- 60 nmol/L, n = 6) followed by a sustained level at approximately 30% of the peak concentration at 30 minutes. Nateglinide led to a rapid and constant reduction in arterial glucose of approximately 30% basal, while glibenclamide promoted a gradual decrease to approximately 50% basal at 120 minutes. An increase in plasma insulin level by nateglinide of 4 times basal (218 +/- 58 pmol/L v 47 +/- 3 pmol/L, P <.05, n = 6) occurred at 6 to 10 minutes followed by sustained release of 1.4 times basal (67 +/- 15 pmol/L, n = 6). The insulin surge was more than doubled (484 +/- 209 pmol/L, n = 6) under a euglycemic clamp. Insulin release by glibenclamide increased gradually reaching 10-fold basal (449 +/- 166 pmol/L, n = 6) at 60 minutes. This was not enhanced during a euglycemic clamp. Lowering the primed doses of nateglinide resulted in a diminished peak plasma insulin concentration. In contrast, glibenclamide caused only a slower increase, but eventually reaching a similar peak. By increasing the continuous infusion of nateglinide, the sustained insulin release was not altered. Glibenclamide, but not nateglinide, evoked prompt and sustained insulin release in the continuing presence of the other. These results are consistent with the concept that nateglinide produces a quick, but very short-lived, interaction with sulfonylurea (SU)-receptors on plasma membrane by free access of the drug from the cell exterior. In contrast, glibenclamide promotes a slow and longer interaction with the receptor by distribution of the drug into the cell inferior. We conclude, therefore, that not only the different kinetics of gastrointestinal (GI) absorption, but also the inherent difference in the interaction with beta cells is attributed to the different insulin release characteristics between nateglinide and glibenclamide in vivo.

ATP-Binding Cassette Transporters↗

Primary tumour resection of tongue carcinoma based on response to preoperative therapy.

The purpose of this study was to investigate the selection of resection techniques for primary lesions of advanced tongue carcinoma based on the effectiveness of our current preoperative therapy. Forty-three patients with advanced but potentially resectable squamous cell carcinoma of the tongue were included in this study. All patients were treated with preoperative concurrent chemoradiotherapy followed by conventional surgical resection. Semiserial sections of whole surgical specimen of primary lesion were evaluated histopathologically. In patients who achieved 85% and above regression, the extent of residual tumours two-dimensionally and in the deep layers was lesser, and the rate of tumour cell survival was lower, than in other patients. Furthermore, residual tumours tended to be localized to the superficial layers in the centre. These findings suggest that even in advanced tongue carcinomas it is possible to avoid extended resection and perform a less invasive surgery in which the extent of resection is reduced to preserve morphology and function in patients who achieved 65% and above regression following preoperative chemoradiotherapy.

Adult↗

Dogs as alternative intermediate hosts of Taenia solium in Papua (Irian Jaya), Indonesia confirmed by highly specific ELISA and immunoblot using native and recombinant antigens and mitochondrial DNA analysis.

Serology (ELISA and immunoblot) using native glycoproteins, affinity purified glycoproteins, and a recombinant antigen is known to be highly specific to Taenia solium cysticercosis in humans and pigs. These techniques were applied for dogs in the highly endemic area of cysticercosis in Papua (Irian Jaya), Indonesia. Analysis of dog sera by both ELISA and immunoblot revealed 7 of 64 dogs were highly positive. Examination of two sero-positive dogs revealed cysticerci of T. solium in the brain and heart of these dogs. Mitochondrial DNA analysis confirmed that they were the same as T. solium previously confirmed from pigs and biopsies from local people from Irian Jaya. It is suggested that the life cycle of T. solium may be completed not only between humans and pigs but also between humans and dogs.

Animals↗

Weak response of helicobacter pylori antibody is high risk for gastric cancer: a cross-sectional study of 10,234 endoscoped Japanese.

BACKGROUND: A large number of endoscoped members of the general Japanese population were surveyed to investigate the relationship between Helicobacter pylori infection and gastric cancer. Special attention was given to antibody titer and age of the subjects. METHODS: We performed gastrointestinal endoscopy and measured serum anti-H. pylori antibody in 10,234 consecutive Japanese who participated in a health examination program. Gastric cancer, when suspected, was confirmed by histology. We graded the H. pylori antibody titer into three groups in accordance with optical density values by ELISA: 'strongly positive', 'weakly positive', and 'negative'. RESULTS: Among the 10,234 subjects (men/women, 7.021/3,213; mean age, 49.1 years), 4,909 (48%) were strongly positive, 1,750 (17%) were weakly positive, and 3,575 (35%) were negative for H. pylori antibody. Thirty-seven cases of gastric cancer were found among the 10,234 subjects (0.36%); 23/4,909 (0.47%) in the strongly positive group, 9/1,750 (0.51%) in the weakly positive group, and 5/3,575 (0.14%) in the negative group. Both the strongly and weakly positive groups showed a higher risk of gastric cancer than the negative group. In the subjects over age 60, the weakly positive group seemed to show the highest risk for gastric cancer. CONCLUSIONS: In this investigation of 10,234 Japanese, based on endoscopy results, those with serum H. pylori antibody had an increased risk for gastric cancer, while those 'weakly positive' showed a high risk, particularly in the elderly.

Antibodies, Bacterial↗

Effect of suplatast tosilate on airway hyperresponsiveness and inflammation in asthma patients.

Because eosinophilic airway inflammation is a characteristic of bronchial asthma, the treatment of such inflammation is important in the management of this disease. Suplatast tosilate is a novel anti-asthma drug that suppresses eosinophil proliferation and infiltration through selective inhibition of Th2 cytokine synthesis. We investigated the effect of oral suplatast tosilate therapy in patients with mild and moderate asthma. Twenty-eight asthma patients were randomized into two groups with or without suplatast tosilate treatment (100 mg t.i.d. for 28 days). We examined the blood eosinophil counts, eosinophilic cationic protein level, sputum eosinophil count, exhaled nitric oxide level, and airway responsiveness before and after treatment. In patients treated with suplatast tosilate, the eosinophil count in the blood and sputum was significantly decreased after treatment, while there was no such change in the patients without suplatast treatment. The exhaled nitric oxide level and airway responsiveness (measured using an Astograph) were also decreased after treatment with suplatast tosilate, while there were no significant changes in patients without suplatast tosilate. These results strongly suggest that oral administration of suplatast tosilate suppresses airway hyperresponsiveness in asthma patients by reducing eosinophilic inflammation in the airways.

Adult↗

Inhibition of human T-lymphotropic virus type I gene expression by the Streptomyces-derived substance EM2487.

EM2487, a Streptomyces-derived substance, has previously been shown to inhibit HIV-1 replication in both acutely and chronically infected cells. In this study, we found that EM2487 was also a selective inhibitor of human T-lymphotropic virus type I (HTLV-I) replication in persistently infected cells. Its 50% effective concentrations for HTLV-I p19 antigen production were 3.6 and 1.2 microM in MT-2 and MT-4 cells, respectively. However, the compound did not reduce cell proliferation and viability at these concentrations. The 50% cytotoxic concentrations of EM2487 were 30.6 and 5.7 microM in MT-2 and MT-4 cells, respectively. The compound also displayed selective inhibition of HTLV-I production in peripheral blood mononuclear cells obtained from patients with HTLV-I-associated myelopathy/tropical spastic paraparesis. Quantitative reverse transcription PCR analysis revealed that EM2487 selectively suppressed HTLV-I mRNA synthesis in MT-2 cells in a dose-dependent fashion. However, the compound did not inhibit endogenous Tax-induced HTLV-I long terminal repeat-driven reporter gene expression. Furthermore, intracellular Tax accumulation was not suppressed in MT-2 cells exposed to EM2487. These results suggest that the inhibition occurred at the viral transcription level, but it cannot be attributed to the inhibition of the Tax function.

Antiviral Agents↗

Eimeria organisms develop in the epithelial cells of equine small intestine.

Histopathologic and immunohistochemical examinations were performed to determine the origin of host cells parasitized by Eimeria in the small intestines collected from five foals. Eimeria organisms at various stages (mainly microgametes and macrogametes) were frequently found in the cytoplasm of hypertrophied host cells in the lamina propria at the tips of villi of the jejunum and ileum. The cytoplasm of the host cell was immunohistochemically positive for cytokeratin AE1/AE3 and cytokeratin 13 and was negative for vimentin, desmin, alpha-smooth muscle actin, chromogranin A, neuron-specific enolase, and factor VIII. The host cells parasitized by Eimeria species had the immunostaining characteristics of epithelial cells but not of mesenchymal cells, endothelial cells of lacteals or capillaries, smooth muscle cells or neuroendocrine cells. These results suggest that the host cell of Eimeria species is possibly derived from intestinal epithelial cells and then displaced into the lamina propria of the small intestine.

Actins↗

Recent advances in basic and applied science for the control of taeniasis/cysticercosis in Asia.

Detection of seven specific bands by immunoblot (IB) using glycoproteins (GPs) purified by lentil-lectin affinity chromatography has been the gold-standard for neurocysticercosis (NCC) serodiagnosis since 1989. However, due to the presence of contaminants, it was impossible to apply the GPs to ELISA. Our group at Asahikawa Medical College (AMC) succeeded in purifying the GPs by preparative isoelectric focusing; these higher quality GPs were suitable for ELISA. Based on the results of both IB and ELISA testing, developed at AMC for a field survey in Irian Jaya, it became evident that that area had pandemic NCC. We found many NCC patients, pigs full of cysts, and one dog infected with two cysts: these findings were based on serology. Recently, we conducted another survey to detect of the worm carriers of T. solium. Three of the 38 local people were positive by copro-antigen specific to Taenia species; these three patients expelled segments of Taenia spp and these were confirmed as those of T. solium by mitochondrial DNA analysis. When viable eggs of any taeniid species could be obtained, they can be developed into metacestodes in NOD-scid mice; it then becomes possible to analyze morphological dynamics, metacestode antigenicity, the efficacy of new metacestocidal drugs, and mitochondrial DNA. Mitochondrial DNA analysis of the specimens obtained in Irian Jaya was compared with that of other isolates worldwide. T. solium is now divided into two genotypes: the Asian type, and the Africa-American type. Some aspects of the pathological differences between the Asian and Africa-American types and the antigenic components of these two types are discussed.

Animals↗

Deoligomerization of siloxanes with dimethyl carbonate over solid-base catalysts.

Hexamethyldisiloxane and hexamethylcyclotrisiloxane were almost completely deoligomerized with dimethyl carbonate over alumina-supported potassium fluoride catalyst to form methoxytrimethylsilane (85% yield) and dimethoxydimethylsilane (94% yield), respectively, and moreover the addition of a small amount of methanol to the hexamethyldisiloxane deoligomerization reaction enhanced the methoxytrimethylsilane yield to 98%.

Journal Article↗

Expression of three extracellular matrix degradative enzymes in bladder cancer.

The relationship between expression of extracellular matrix degradative enzymes, angiogenesis and survival of multistage bladder cancer was determined. Expression of 3 extracellular matrix degradative enzymes (metalloproteinase-2, -9 and heparanase) and microvessel formation were examined in 40 resected bladder cancer specimens by immunohistostochemic staining, and then the association of the enzyme expression with angiogenesis and various stages of cancer was investigated. Heparanase protein expression in muscular invasive or lymph-node metastatic cancer was significantly higher than in superficial or nonmetastatic cancer, respectively (69% vs. 8%, p < 0.001, and 80% vs. 40%, p = 0.028, respectively). Interestingly, heparanase was expressed at much higher levels than matrix metalloproteinase-2 and -9. The mean microvessel count in cancers with heparanase expression was significantly higher than that in cancers without heparanase expression (32.3 +/- 18.2 vs. 5.5 +/- 6.1, p = 0.0008). The microvessel formation was not associated with the expression of matrix metalloproteinase-2 and -9. The cancer-specific and overall survival rates of patients with heparanase expression were significantly lower than those of patients without it (p = 0.0001 and p = 0.0008, respectively). Multivariate analysis showed that heparanase expression was a significantly independent prognostic factor for both cancer-specific (p = 0.0047) and overall survival (p = 0.0200). Our study suggested that heparanase plays important roles in invasion, angiogenesis and metastasis of bladder cancer, and thus, this molecule could be a new molecule to inhibit invasion, angiogenesis and metastasis of bladder cancer. Moreover, our results indicate that expression of heparanase could be a new prognostic factor of this disease.

Adult↗

Suppression of cytokine production and neural cell death by the anti-inflammatory alkaloid cepharanthine: a potential agent against HIV-1 encephalopathy.

Inflammatory cytokines and human immunodeficiency virus type 1 (HIV-1) gp120 are considered to play an important role in the pathogenesis of HIV-1-associated CNS disorders. These substances are produced predominantly by HIV-1-infected or activated macrophages and microglia in the brain and induce neural cell death. Cepharanthine is a biscoclaurine alkaloid isolated from Stephania cepharantha Hayata and has been shown to have anti-inflammatory, anti-allergic, and immunomodulatory activities in vivo. We previously reported that this compound could inhibit tumor necrosis factor (TNF)-alpha- or phorbol 12-myristate 13-acetate-induced HIV-1 replication in latently infected U1 cells through the inhibition of nuclear factor-kappaB, a potent inducer of HIV-1 gene expression. In the present study, we demonstrated that cepharanthine suppresses the production of inflammatory cytokines and a chemokine, i.e. TNF-alpha, interleukin (IL)-1beta, IL-6, and IL-8, in human monocytic cell cultures, including primary monocyte/macrophage cultures. This effect of cepharanthine was concentration-dependent, and significant suppression was observed at 0.1 microg/mL. Furthermore, the compound also inhibited TNF-alpha- and gp120-induced death of differentiated human neuroblastoma cells at a concentration of 0.04 to 0.2 microg/mL. It penetrates the blood-brain barrier, and a medicine containing cepharanthine as a major component has been used in Japan for the treatment of patients with chronic inflammatory diseases. Thus, cepharanthine should be investigated further for its therapeutic and prophylactic potential in HIV-1-associated CNS disorders.

AIDS Dementia Complex↗

Both heavy strand replication origins are active in partially duplicated human mitochondrial DNAs.

The replication of human mitochondrial DNA (mtDNA) is initiated from a pair of displaced origins, one priming continuous synthesis of daughter-strand DNA from the heavy strand (OH) and the other priming continuous synthesis from the light strand (OL). In patients with sporadic large-scale rearrangements of mitochondrial DNA (i.e., partially-deleted [Delta-mtDNA] and partially-duplicated [dup-mtDNA] molecules), the dup-mtDNAs typically contain extra origins of replication, but it is unknown at present whether they are competent for initiation of replication. Using cybrids harboring each of two types of dup-mtDNAs-one containing two OHs and two OLs, and one containing two OHs and one OL-we used ligation-mediated polymerase chain reaction (LMPCR) to measure the presence and relative amounts of nascent heavy strands originating from each OH. We found that the nascent heavy strands originated almost equally from the two OHs in each cell line, indicating that the extra OH present on a partially duplicated mtDNA is competent for heavy strand synthesis. This extra OH could potentially confer a replicative advantage to dup-mtDNAs, as these molecules may have twice as many opportunities to initiate replication compared to wild-type (or partially deleted) molecules.

Cell Line↗

B cell adaptor containing src homology 2 domain (BASH) links B cell receptor signaling to the activation of hematopoietic progenitor kinase 1.

The B cell adaptor containing src homology 2 domain (BASH; also termed BLNK or SLP-65), is crucial for B cell antigen receptor (BCR)-mediated activation, proliferation, and differentiation of B cells. BCR-mediated tyrosine-phosphorylation of BASH creates binding sites for signaling effectors such as phospholipase Cgamma (PLCgamma)2 and Vav, while the function of its COOH-terminal src homology 2 domain is unknown. We have now identified hematopoietic progenitor kinase (HPK)1, a STE20-related serine/threonine kinase, as a protein that inducibly interacts with the BASH SH2 domain. BCR ligation induced rapid tyrosine-phosphorylation of HPK1 mainly by Syk and Lyn, resulting in its association with BASH and catalytic activation. BCR-mediated activation of HPK1 was impaired in Syk- or BASH-deficient B cells. The functional SH2 domain of BASH and Tyr-379 within HPK1 which we identified as a Syk-phosphorylation site were both necessary for interaction of both proteins and efficient HPK1 activation after BCR stimulation. Furthermore, HPK1 augmented, whereas its kinase-dead mutant inhibited IkappaB kinase beta (IKKbeta) activation by BCR engagement. These results reveal a novel BCR signaling pathway leading to the activation of HPK1 and subsequently IKKbeta, in which BASH recruits tyrosine-phosphorylated HPK1 into the BCR signaling complex.

Adaptor Proteins, Signal Transducing↗