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Biomedical subjects

Akira Kubota

Publications and source records attributed to Akira Kubota.

At least 19 recordsLinked to original sources
PubMed2006

Inhibitory effect of Lactobacillus gasseri TMC0356 and Lactobacillus GG on enhanced vascular permeability of nasal mucosa in experimental allergic rhinitis of rats.

The nasal vascular permeability of ovablumin (OVA)-sensitized Brown Norway rats was evaluated by analyzing a brilliant blue concentration in perfusate from the nose after exposure of the nasal mucus to OVA. Oral administration of Lactobacillus GG and L. gasseri TMC0356 significantly inhibited the increase in nasal vascular permeability (P<0.01). The serum IgE of the tested rats also decreased, although the change was not statistically significant. These results indicate that Lactobacillus GG and L. gasseri TMC0356 might alleviate nasal allergic symptoms by suppressing the increase in nasal vascular permeability caused by local inflammation associated with allergic rhnititis.

Animals↗
PubMed2006

Conversion of mammalian Müller glial cells into a neuronal lineage by in vitro aggregate-culture.

Mammalian Müller glial cells are major glial cells in the retina. Here we report that these glial cells can be redirected towards a neuronal lineage by an aggregate-culture in vitro. Rat and macaque Müller glial cells did not express neuronal markers except after transfer to adhesive conditions. Furthermore, this expression could only take place in the presence of platelet-derived growth factor and valproic acid. We compared a normal monolayer-culture and an aggregate-culture, and rat Müller glial cells could only differentiate into neurons under non-adhesive conditions. However, Müller glial cells did not express the photoreceptor markers in vitro. After transplantation into the subretinal space, a retina-specific niche, rat Müller glial cells expressed the photoreceptor-specific marker, opsin (RET-P1). We demonstrate the potential of mammalian Müller glial cells as a source of photoreceptors, which may possibly contribute to the treatment of degenerative retinal diseases such as retinitis pigmentosa.

Animals↗
PubMed2006

Cytochrome P450 1A4 and 1A5 in common cormorant (Phalacrocorax carbo): evolutionary relationships and functional implications associated with dioxin and related compounds.

The present study characterized cytochrome P4501A (CYP1A) isoforms from common cormorant (Phalacrocorax carbo) with regard to their evolutionary relationships and their roles in disposition of dioxin and related compounds (DRCs). Two clones isolated from a cormorant liver cDNA library were named CYP1A4 and CYP1A5 on the basis of greatest overall amino acid identity shared with chicken (Gallus gallus) CYP1A4 (78%) and CYP1A5 (78%), respectively. Spatial heterogeneity in phylogenetic signal along the sequences strongly indicated that cormorant CYP1A4 and CYP1A5 have undergone partial interparalog gene conversion, similar to chicken and mammalian CYP1As. Phylogenetic analysis of a putatively unconverted region produced a tree topology consistent with the orthology of avian CYP1A5s with mammalian CYP1A2s and avian CYP1A4s with mammalian CYP1A1s. Hepatic CYP1A4 and CYP1A5 mRNA levels in wild cormorants from Lake Biwa, Japan, were quantified to examine the effects of DRCs on isoform-specific expression and to evaluate the toxicokinetics of DRCs in which CYP1A expression is involved. Both CYP1A4 and CYP1A5 mRNA levels were positively correlated with total tetrachlorodibenzo-p-dioxin toxic equivalents and concentrations of each congener in most cases in the liver, suggesting the induction of both enzymes through a shared transcriptional mechanism. The lack of correlation of 2,3,7,8-tetrachlorodibenzofuran and 3,3',4,4'-tetrachlorobiphenyl (PCB77) to CYP1A gene expression is likely due to the rapid metabolism of these two congeners. Liver-to-muscle concentration ratios for most DRC congeners except PCB77 and mono-ortho coplanar polychlorinated biphenyls significantly increased with an elevation of CYP1A4 and CYP1A5 mRNA levels. The present data suggest that hepatic sequestration of some DRCs occurs in cormorant via binding to either CYP1A5 or both CYP1A4 and CYP1A5.

Amino Acid Sequence↗
PubMed2006

Transplantable retinal pigment epithelial cell sheets for tissue engineering.

The native retinal pigment epithelium (RPE) exists as a monolayer structure and is critically involved in the maintenance of photoreceptors. Damage or destruction of the RPE due to a variety of diseases therefore often results in loss of vision. With regenerative purposes in mind, we have examined various culture conditions such as the initial cell density and the addition of various supplements in an effort to produce transplantable RPE cell sheets that can be harvested without defects. We demonstrate that the cell density in cultured RPE sheets increased linearly with the number of seeded cells and that RPE sheets were harvested without defects and limited contraction due to cytoskeletal reorganization, when TGF-beta2 was added to the growth medium. Results from histological analysis and the measurement of trans-epithelial resistance also demonstrates that these RPE cell sheets exist as monolayer structure, similar to the native RPE, with intact cell-to-cell junctions. Therefore, these methods provide significant insight into the fabrication of transplantable RPE cell sheets that can be applied to RPE regenerative therapies to restore lost vision.

Cell Count↗
PubMed2006

[Adjuvant chemotherapy (nedaplatin/UFT) after concurrent chemoradiotherapy for locally advanced head and neck squamous cell carcinoma].

To evaluate the efficacy of adjuvant chemotherapy after concurrent chemoradiotherapy, 41 previously untreated patients with locally advanced and resectable head and neck squamous cancer were enrolled in a study to compare adjuvant chemotherapy (Nedaplatin/UFT) after concurrent chemoradiotherapy (CDDP/5-FU) and concurrent chemoradiation alone. Nine of the patients had stage III tumors and 32 had stage IV tumors. The primary tumor site was the hypopharynx in 14 patients, the larynx in 12 patients, the oral cavity in 9 patients, and the oropharynx in 6 patients. Treatment consisted of 6 courses of Nedaplatin (80 mg/m2) repeated at 4-week intervals and one year of the oral administration of UFTE (400 mg/day) after concurrent chemoradiotherapy at an outpatient clinic. Toxicities included leukopenia (grade 3, 15.4%) and thrombocytopenia (grade 3, 7.7%). One death from a gastric ulcer occurred. The median overall survival time was 30.1 months (5.5-50.1 months) for the adjuvant chemotherapy group and 21.7 months (4.0-48.8 months) for the control group. The progression-free survival period was 22.8 months (5.6-33.9 months) for the adjuvant chemotherapy group and 26.5 months (5.6-33.9 months) for the control group. The two-year overall survival rate was 73.3% for the adjuvant chemotherapy group and 55.7% for the control group. A significant difference was observed in the two-year progression-free survival rates: 66.9% for the adjuvant chemotherapy group and 27.8% for the control group (p = 0.03290). Among the patients with a partial response to concurrent chemoradiotherapy, in particular, a significant difference in the two-year progression-free survival rates was seen : 59.3% for the adjuvant chemotherapy group and 15.3% for the control group (p = 0.01102). The rate of loco-regional failure was 29.6% for the adjuvant chemotherapy group and 64.3% for the control group (p = 0.0716). Distant metastasis was not detected in either group. The rate of organ preservation was 66.7% for the adjuvant chemotherapy group and 35.7% for the control group (p = 0.1183). This adjuvant chemotherapy regimen might improve the loco-regional control rates after concurrent chemoradiotherapy.

Antineoplastic Agents↗
PubMed2006

Crucial problem in rapid spectrophotometric determination of 2,4,6-trinitrotoluene and its breakthrough method.

A rapid spectrophotometric determination for 2,4,6-trinitrotoluene (TNT) is significant because this method is suitable for simultaneous analyses of the numerous samples. We found one problem that TNT reduction products interfere with the TNT detection in this assay, and we overcame this problem by heating the samples at 95 degrees C, resulting in the production of compounds that did not interfere.

Biodegradation, Environmental↗
PubMed2006

One-step isolation and identification of hydroxylamino-dinitrotoluenes, unstable products from 2,4,6-trinitrotoluene metabolites, with thin-layer chromatography and laser time-of-flight mass spectrometry.

Two kinds of hydroxylamino-dinitrotoluenes (HADNTs), 2-hydroxylamino-4,6-dinitrotoluene (2HADNT) and 4-hydroxylamino-2,6-dinitrotoluene (4HADNT), are known to be major metabolites produced from 2,4,6-trinitrotoluene (TNT) by bacteria. These chemicals could not be identified as TNT metabolites produced by Pseudomonas sp. strain TM15 because the mass spectra of these chemicals could not be obtained by liquid chromatography-mass spectrometry (MS) or gas chromatography-MS, which are the classic methods for identifying the metabolites of xenobiotics. However, these problems are overcome by isolating 2HADNT and 4HADNT from TNT metabolites with one-step thin-layer chromatography using dichloromethane as the developing solvent, and individually extracting them into acetonitrile by collecting spots of 2HADNT and 4HADNT. The purity of each HADNT was approximately 98%, based on the results of high-performance liquid chromatographic analyses. 2HADNT and 4HADNT are identified by obtaining their mass spectra with laser time-of-flight MS. 2HADNT and 4HADNT dissolve in distilled water and are spontaneously broken down with time. Also, heat treatment (increasing temperatures) and dissolved oxygen accelerate the destruction of HADNTs. This technique may be applicable for the identification and exact quantitative analysis of unstable and fragile compounds such as HADNTs.

Chromatography, Thin Layer↗
PubMed2006

Preliminary human study for possible alteration of serum immunoglobulin E production in perennial allergic rhinitis with fermented milk prepared with Lactobacillus gasseri TMC0356.

The fermented milk prepared with Lactobacillus gasseri TMC0356 was administered at 200 ml per day for 4 weeks to 15 subjects with high serum IgE levels and perennial allergic rhinitis. The serum total IgE concentration was significantly reduced after 28 days' exposure to the fermented milk (P <0.05) compared to that before the intervention. The serum IgE specific to Acari and those to Japanese cedar pollen also significantly declined (P <0.05). T helper 1 (Th1) cells in the composition of their peripheral blood mononuclear cells (PBMCs) significantly increased after 14 days (P <0.01) and after 28 days (P <0.05). These results suggest that the fermented milk prepared with L. gasseri TMC0356 may alter serum IgE concentration, at least partly by enhancement of Th1 immune responses of the subjects with high concentration of serum IgE. However, further studies are still necessary to know the underlying mechanisms by which the tested fermented milk could influence the host immunity.

Adolescent↗
PubMed2006

Congener-specific toxicokinetics of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls in black-eared kites (Milvus migrans): cytochrome P4501A-dependent hepatic sequestration.

Concentrations of dioxins and related compounds (DRCs), such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs), were determined in black-eared kites (BEKs; Milvus migrans) collected from the Kanto district in Japan. Total 2,3,7,8-tetra-CDD toxic equivalents (TEQs) were in the range of 99 to 3,800 pg/g lipid weight in the liver and 42 to 760 pg/g lipid weight in the pectoral muscle. Three congeners, including PCB 126, 2,3,4,7,8-penta-CDF, and 1,2,3,7,8-penta-CDD, made a greater contribution to total TEQs in both tissues. Levels of ethoxyresorufin-O-deethylase activity and a cross-reactive protein with anti-rat cytochrome P4501A (CYP1A) polyclonal antibodies showed no significant correlation with hepatic TEQs. This may be attributed to low sensitivity and insufficient TEQ levels to cause CYP1A induction, high metabolic potential of a series of congeners, and influence of CYP1A inducers other than DRCs. Most of the PCDD/ Fs and non-ortho Co-PCBs exhibited a total TEQ- and CYP1A-dependent increase in the liver to muscle concentration ratios, implying their concentration-dependent hepatic sequestration in which CYP1A was involved. Comparison of the toxicokinetics in avian species revealed that BEKs possibly have higher potentials than common cormorants for metabolizing and sequestering certain congeners in the liver in terms of hepatic concentration profiles and liver:muscle concentration ratios, respectively. These results clearly indicate that the toxicokinetics of DRCs is congener-, tissue-, and species-specific as well as concentration-dependent. Therefore, CYP1A expression is one of the critical factors that determine the toxicokinetics in wild avian species.

Animals↗
PubMed2006

A fatal case of saponated cresol ingestion.

We describe here a case of suicidal poisoning by saponated cresol ingestion. A 41 year-old male was found unconsciousness in a park in the early morning, and an empty bottle of saponated cresol was found beside him. His death was confirmed approximately 2 hours later, despite attempts at resuscitation and intensive care. The autopsy revealed severe morphological damage of the upper gastrointestinal tract and congestion of the lung. We also observed by histopathological examination severe lung edema and severe erosion of the esophagus and stomach. Toxicological analysis also identified a high concentration of cresol isomer in the blood and gastric contents. The cause of death was given as cresol poisoning, based on the results of the autopsy and toxicological examination.

Adult↗
PubMed2005

Hepatic CYP1A induction by dioxin-like compounds, and congener-specific metabolism and sequestration in wild common cormorants from Lake Biwa, Japan.

The present study examines the effects of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs) on hepatic cytochromes P450 (CYP) in the wild population of common cormorants from Lake Biwa, Japan, and discusses functional roles of CYP1A in terms of correlation analysis between tissue concentrations of individual congeners and expression levels of CYP1A. Levels of alkoxyresorufin (methoxy-, ethoxy-, pentoxy-, and benzyloxyresorufin) O-dealkylase activities and a protein cross-reacted with anti-rat CYP1A1 polyclonal antibodies showed significant positive correlations with total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) or TEQs for most individual congeners in the liver of cormorants, suggesting induction of CYP1A-like protein by these chemicals. In contrast, TEQs for lower chlorinated congeners, 2,3,7,8-T4CDF and PCB77, showed relatively low correlations with the expression level of CYP1A-like protein. Concentrations of 2,3,7,8-T4CDF and PCB77 normalized to a relatively recalcitrant congener, PCB169, were negatively correlated with the CYP1A-like protein level. These results indicate preferential metabolism of those congeners by CYP1A-like protein that was induced by TEQs. Concentration ratios of liverto pectoral muscle for certain congeners significantly increased with an elevation of the CYP1A-like protein level. Comparing the results in the present study with those of previous studies using rodents treated with certain dioxin-like congeners, these congeners in the liver may be sequestered by CYP1A. Levels of cross-reactive proteins with anti-rat CYP2B1, CYP2C6, and CYP3A2 polyclonal antibodies correlated with neither TEQs nor liver/muscle concentration ratios of congeners. We conclude that the potential for CYP1A induction, and metabolism and sequestration of dioxin-like compounds by CYP1A, may be a critical factor for assessing the ecological risk in wild avian species.

Animals↗
PubMed2005

Protection against bleomycin-induced lung injury by IL-18 in mice.

The role of interleukin (IL)-18 in the protection from interstitial pneumonia and pulmonary fibrosis induced by bleomycin (BLM) was investigated by comparing the severity of BLM-induced lung injuries between wild-type and C57BL/6 mice with a targeted knockout mutation of the IL-18 gene (IL-18-/- mice). IL-18-/- mice showed much worse lung injuries than wild-type mice, as assessed by the survival rate, histological images, and leukocyte infiltration in the bronchoalveolar lavage fluid and myeloperoxidase activity. In wild-type mice, administration of IL-18 before BLM instillation resulted in suppression of lung injuries, increases in the hydroxyproline content, and decreases in the granulocyte-macrophage colony-stimulating factor content in the lung. Preadministration of IL-18 also resulted in prevention of the reduction of the lung IL-10 content caused by BLM-induced damage of alveolar epithelial. BLM instillation suppressed superoxide dismutase (SOD) activity in IL-18-/- mice to a greater extent than in wild-type mice. Pretreatment of IL-18 augmented Mn-containing superoxide dismutase (Mn-SOD) messenger RNA expression and SOD activity in the lung and prevented the reduction of SOD activity caused by BLM in both wild-type and IL-18-/- mice. These results suggest that IL-18 plays a protective role against BLM-induced lung injuries by upregulating a defensive molecule, Mn-SOD.

Animals↗
PubMed2005

Soluble CD44 standard, CD44 variant 5 and CD44 variant 6 and their relation to staging in head and neck cancer.

CONCLUSION: The possible roles of CD44st, CD44v5 and CD44v6 in the prognosis of head and neck cancer deserve further elucidation and evaluation with long-term patient follow-up. OBJECTIVE: Standard CD44 (CD44st), CD44 variant 5 (CD44v5) and CD44 variant 6 (CD44v6) are expressed in human malignant cells and tissues. The mechanism of their expression remains unclear, but has been reported to be associated with the progression and metastasis of malignancies. Recently, it has frequently been reported that the prognosis of head and neck cancer is associated with expression of the cell adhesion molecule CD44. MATERIAL AND METHODS: We investigated correlations between the soluble adhesion molecule CD44 and clinicopathologic variables, for example, age, sex, histologic grade, tumor size, lymph node status, distant metastasis and TNM stage. The pre- and post-treatment serum levels of CD44st, CD44v5 and CD44v6 were determined by means of ELISAs in 81 patients with head and neck cancer and 20 healthy volunteers (controls). RESULTS: In the cancer patients, the pre-treatment median serum levels of CD44st, CD44v5 and CD44v6 were 327 +/- 134, 312 +/- 118 and 211 +/ 110 ng/ml, respectively. The corresponding post-treatment levels were 185 +/- 103, 177 +/- 90 and 110 +/- 65 ng/ml. In the healthy volunteers, the median serum levels of CD44st, CD44v5 and CD44v6 were 133 +/- 40, 142 +/- 39 and 86 +/- 22 ng/ml, respectively. In the cancer patients, there was no significant correlation between the serum levels of CD44st, CD44v5 and CD44v6 and the clinicopathological variables. The pre-treatment serum levels of CD44st, CD44v5 and CD44v6 were closely associated with TNM stage (p = 0.0017, 0.0005 and 0.0046, respectively). The median pre-treatment serum levels of CD44st, CD44v5 and CD44v6 were significantly higher than those in the control group (p = 0.0002, 0.0065 and 0.0038, respectively). The median post- treatment serum levels of CD44st, CD44v5 and CD44v6 were significantly lower than the pre-treatment levels (p = 0.0003, 0.0027 and 0.0034, respectively).

Adult↗
PubMed2005

An autopsy case of imipramine poisoning.

We present a fatal imipramine poisoning. Quantitative analysis of imipramine and its metabolite, desipramine, was performed by high-performance liquid chromatography. The concentrations of imipramine and desipramine were 18.67 microg/mL and 6.21 microg/mL in heart blood and 6.90 microg/mL and 1.77 microg/mL in the femoral venous blood, respectively. We concluded that the cause of death was due to imipramine poisoning.

Antidepressive Agents, Tricyclic↗
PubMed2005

Reconstructing arbitrarily focused images from two differently focused images using linear filters.

We present a novel filtering method for reconstructing an all-in-focus image or an arbitrarily focused image from two images that are focused differently. The method can arbitrarily manipulate the degree of blur of the objects using linear filters without segmentation. The filters are uniquely determined from a linear imaging model in the Fourier domain. An effective and accurate blur estimation method is developed. The simulation results show that the accuracy and computational time of the proposed method are improved compared with the previous iterative method and that the effects of blur estimation error on the quality of the reconstructed image are very small. The method performs well for real images acquired without visible artifacts.

Algorithms↗
PubMed2005

Effect of orally administered non-viable Lactobacillus cells on murine humoral immune responses.

BALB/c mice were immunized intraperitoneally with the food antigen ovalbumin (OVA) while they were fed with Lactobacillus GG heated killed cell preparation. The oral administration of Lactobacillus GG did not appear to modify the antigen-augmented serum IgE in the tested mice but significantly augmented serum OVA specific IgG in the tested mice fed with a diet containing 0.1% Lactobacillus GG as the non-viable cell preparation (P< 0.05). The fecal OVA specific IgA of the tested mice fed with nonviable Lactobacillus GG cells was also significantly elevated (P< 0.05) compared to those from OVA immunized mice. The spleen cells of mice fed with non-viable Lactobacillus GG cells secreted more IL-6 (P< 0.01). These results suggest that the non-viable Lactobacillus GG can augment the systemic and mucosal immune responses in a host animal favoring secretory IgA but not IgE in an adjuvant-like manner.

Administration, Oral↗
PubMed2005

Expression of SPARC in tongue carcinoma of stage II is associated with poor prognosis: an immunohistochemical study of 86 cases.

SPARC (secretory protein acidic and rich in cysteine), also known as osteonectin or BM-40, associates with progression in various kinds of tumors. We have examined whether SPARC expression can be a prognostic marker for patients with head and neck squamous cell carcinomas (HN-SCC). We examined immunolocalization of SPARC in 86 clinical specimens of tongue carcinoma. Although there was no correlation between SPARC positivity in the tumor cells and tumor stages, the 5-year overall survival rate was significantly lower in the SPARC positive cases (28.6%) than in the SPARC negative cases (91.7%), confined to stage II patients (p < 0.001, Wilcoxon test). Additionally, in stage II cases (n = 3), frequency of the postoperative metastasis was significantly higher in SPARC positive cases (5/8, 62.5%) than in the negative cases (1/15, 6.7%) (p < 0.01, chi2 test). Together with these results, SPARC can be a beneficial prognostic marker for the stage II tongue carcinoma, of which clinical outcomes are sometimes difficult to predict.

Female↗