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Biomedical subjects

T Hirano

Publications and source records attributed to T Hirano.

At least 217 records · Page 12Linked to original sources
PubMed2000

Rapid patterning in 2-D cultures of Dictyostelium cells and its relationship to zonal differentiation.

Rapid patterning has been observed in confined 2-D cultures of Dictyostelium discoideum Ax-2 cells as an outer dark zone and a inner light zone. The width of outer zone was usually approximately100 microm, irrespective of the size of cell masses under atmospheric conditions. The width of the outer zone, however, changed depending on external O2 concentrations and reached up to 250 microm at 100% O2. A clear regional difference in tetramethyl rhodamine methyl ester (TMRM) staining was noticed between the outer zone and the inner zone: the inner zone was more strongly stained with TMRM than the outer zone, which faced the air. Using inhibitors of oxidative phosphorylation (dinitrophenol (DNP) or NaN3) and a specific inhibitor of CN-resistant respiration (benzohydroxamic acid (BHAM)), it has been demonstrated that the outer zone is basically formed by the O2 threshold for oxidative phosphorylation, while the inner cells mainly perform cyanide-resistant respiration. When cells around the early mound stage (just before prestalk and prespore differentiation) were cultured as 2-D cell masses, ecmA-expressing cells (pstA cells), ecmB-expressing cells (pstB cells) and D19-expressing cells (prespore; psp cells), arose in a position-dependent manner in the outer zone. In the inner zone, cell motility seemed to be markedly impaired and neither prestalk nor prespore differentiation occurred. In addition, once-differentiated prespore cells were found to dedifferentiate rapidly in the inner zone. The reason for dedifferentiation as well as for failure of cells to differentiate in the inner zone is discussed with reference to O2 radicals.

Animals↗
PubMed2000

Enterocolitis with pathogenic Escherichia coli infection in renal transplant recipients: case reports.

PURPOSE: We report three cases of enterocolitis associated with pathogenic Escherichia coli infection in renal transplant recipients. METHODS/RESULTS: Patients presented with abdominal pain and diarrhea at 1, 3 and 7 years after living-related renal transplantation. Pathogens of enterocolitis were identified by stool culture as verotoxin-2-producing O157:H7 E. coli, non-verotoxin-producing E. coli 06 and 0125. All patients were basically treated with fluid replacement with additional fosfomycin administration in the patient with O157:H7 E. coli infection. Immunosuppressive drugs were kept at maintenance doses throughout the treatment. CONCLUSION: All patients recovered uneventfully within 10 days after the onset of enterocolitis without severe complications.

Adult↗
PubMed2000

Pharmacological effects of urinary products obtained after treatment with saiboku-to, a herbal medicine for bronchial asthma, on type IV allergic reaction.

To define the anti-allergic components in Saiboku-To, a herbal medicine for bronchial asthma, we examined the effects of 11 compounds found in post-administrative urine of Saiboku-To on concanavalin A-induced human lymphocyte blastogenesis in vitro and picryl chloride (PC)-induced mouse ear swelling in vivo. The urinary products of Saiboku-To were flavonoids and lignans derived from the constitutional herbs and their hydrogenated metabolites. Medicarpin derived from Glycyrrhiza glabra, magnolol and 8,9-dihydroxydihydromagnolol from Magnolia officinalis, baicalein, wogonin and oroxylin A from Suctellaria baicalensis inhibited lymphocyte blastogenesis in dose-dependent fashion with IC50 values ranging from 3.0 to 7.7 micrograms/mL, which corresponded to 20-100 times that of prednisolone IC50 (0.08 microgram/mL). Davidigenin, dihydrowogonin and dihydrooroxylin A, which are hydrogenated metabolites of liquiritigenin, wogonin and oroxylin A, respectively, had no or little effects on lymphocyte blastogenesis. Oral administration of Saiboku-To, medicarpin, baicalein, magnolol and baicalin (100 mg/kg), inhibited PC-induced ear swelling significantly by 23.5, 40.1, 30.5, 23.6 and 20.9%, respectively, though the effects were weaker than that of 5 mg/kg of prednisolone (52.9%). The results suggested that flavonoids and lignans tested in the present study were implicated in anti-asthmatic effect of Saiboku-To through suppression of type IV allergic reaction.

Animals↗
PubMed2000

Clinical impact of cyclosporine cellular pharmacodynamics in minimal change nephrotic syndrome.

BACKGROUND: Cellular pharmacodynamics of cyclosporine (INN, cyclosporin) is considered to be closely implicated in clinical efficacy of the drug in kidney transplantation and other immunologic disorders. We applied this strategy to patients with minimal change nephrotic syndrome to predict individual clinical efficacy of cyclosporine. METHODS: Drug sensitivity tests were carried out with peripheral blood mononuclear cells from 31 patients with minimal change nephrotic syndrome. The 50% lymphocyte-mitosis inhibition of cyclosporine on in vitro blastogenesis of peripheral blood mononuclear cells stimulated with concanavalin A were estimated, and interpatient variations of 50% lymphocyte-mitosis inhibition were evaluated. The relationship between cyclosporine-50% lymphocyte-mitosis inhibition and clinical outcomes indicated a decrease of urinary protein and the period required for complete remission under cyclosporine therapy was examined in 14 patients. We also evaluated the correlation between cyclosporine-50% lymphocyte-mitosis inhibition and interleukin-2 production and percentages of interleukin 2 receptor-positive peripheral blood mononuclear cells in vitro. RESULTS: Cyclosporine 50% lymphocyte-mitosis inhibition on peripheral blood mononuclear cell blastogenesis deviated largely between patients from 0.2 to 86.0 ng/mL. We found a statistically significant negative correlation between cyclosporine-50% lymphocyte-mitosis inhibition in vitro and decreasing rates of urinary protein at 1 week after onset of cyclosporine administration (r = -0.655, P < .02). When we arbitrarily divide the 14 patients who received cyclosporine therapy according to their median 50% lymphocyte-mitosis inhibition of cyclosporine into two groups, that is, a high-sensitivity group (50% lymphocyte-mitosis inhibition < 18.1 ng/mL, n = 6) and a low-sensitivity group (50% lymphocytemitosis inhibition > 18.1 ng/mL, n = 8), the period required for complete remission was significantly shorter in the high-sensitivity group (P < .03). The 50% lymphocyte-mitosis inhibition of cyclosporine on interleukin-2 production in culture medium was correlated with 50% lymphocyte-mitosis inhibition of the drug on peripheral blood mononuclear cell blastogenesis (r = 0.806, P < .02). Decreasing rates of interleukin-2R-positive cells by cyclosporine treatment in vitro were negatively correlated with peripheral blood mononuclear cells blastogenesis in the presence of the drug (r = -0.694, P < .02). CONCLUSIONS: Peripheral blood mononuclear cell response to cyclosporine in vitro is closely related to clinical efficacy of the drug in minimal change nephrotic syndrome. Peripheral blood mononuclear cell resistance to cyclosporine was correlated with ability of the cells to express interleukin 2 and interleukin 2R.

Adult↗
PubMed2000

Transduction of a murine dominant negative activation transcription factor 1 increases cell surface expression of the class I MHC on a human epidermoid tumor cell line.

The transcription of the MHC class I genes is regulated by interaction of cis-elements, located in the 5' genomic flanking regions, with sequence-specific trans-factors. We have identified a cis-regulatory element, 5'-TGACGCG-3', of the H-2D(d) gene. This cyclic adenosine-3',5'-monophosphate regulatory element (CRE)-like sequence, named H-2 binding factor 1 (H-2 BF1) binding motif, is highly conserved among species. In addition, we found that homo- and heterodimers of activation transcription factor 1 (ATF-1) and CRE binding protein (CREB) associate with the H-2 BF1 binding motif and activate transcription of the H-2D(d) gene. Here we demonstrate that a homologue of ATF-1, originally isolated and designated ATF-1DN, acts as a dominant repressor, blocking the ability of wild-type ATF-1 and CREB to bind to the H-2 BF1 probe in electrophoretic mobility shift assays (EMSA). We have utilized this molecule to analyze the participation of the H-2 BF1 complexes, consisting of the H-2 BF1 binding motif and ATF-1/CREB trans-factors, in the physiological regulation of MHC class I expression in tissue culture cells. A human epidermoid carcinoma cell line, A431, was transfected with ATF-1DN and clones expressing the gene transcripts were selected. When analyzed in the EMSA, nuclear proteins prepared from these clones exhibited a decreased shift of the H-2 BF1 probe corresponding to the levels of the ATF-1DN gene expression. Additionally, MHC class I expression of cells with reduced H-2 BF1 activity was significantly higher than in control cells lacking ATF-1DN. These findings indicate that in these carcinoma cells, the H-2 BF1 complexes negatively regulate the constitutive expression of MHC class I.

Activating Transcription Factor 1↗
PubMed2000

CD9 is expressed on human endometrial epithelial cells in association with integrins alpha(6), alpha(3) and beta(1).

Recently we reported that CD9 is involved in the invasion of a trophoblast-like choriocarcinoma cell line, BeWo, probably through the regulation of integrin functions. Integrins have also been reported to be expressed in the human endometrium and it has been suggested that they play important roles in blastocyst implantation. This study used immunohistochemistry to investigate the expression of CD9 in the endometrium during the menstrual cycle. CD9 was found to be intensely expressed on the cell surface of the glandular epithelium throughout the menstrual cycle without any apparent differences in staining intensity. In addition, Western blotting analysis of the affinity-purified proteins confirmed that CD9 was associated with integrins beta(1), alpha(3) and alpha(6) in the human endometrium. Therefore it can be concluded that CD9, in association with integrins alpha(6), alpha(3) and beta(1), is a constitutive molecule of the endometrial glandular epithelium. These results also suggest that CD9 may be an important regulator of these integrins in the human endometrium.

Antibodies, Monoclonal↗
PubMed2000

Anti-CD9 monoclonal antibody-stimulated invasion of endometrial cancer cell lines in vitro: possible inhibitory effect of CD9 in endometrial cancer invasion.

Cell surface marker CD9 has been reported to play a role in inhibiting trophoblastic cell invasion. Since the invasive properties of cancer cells may resemble those of trophoblasts, we decided to investigate the role of CD9 in the invasion of endometrial cancer cells. In normal human endometrium, CD9 was found to be constitutively expressed on epithelial cells, as reported previously. While epithelial cells of endometrial hyperplasia (n = 5) were also positive for the expression of CD9, endometrial adenocarcinomas (n = 15) showed reduced expression. In order to clarify the significance of this reduced CD9 expression in endometrial cancer, an in-vitro invasion assay system was used to assess the effect of anti-CD9 monoclonal antibody (mAb) on the invasive properties of endometrial cancer cell line. Anti-CD9 mAb significantly enhanced invasion of the RL95-2 and Ishikawa cell lines, without affecting cell proliferation. Since CD9 is associated with the integrin subunits beta(1), alpha(3) and alpha(6) in human endometrium, we investigated the functional relationship between CD9 and these integrins in the RL95-2 cell line. Monoclonal antibodies against the integrins beta(1), alpha(3) and alpha(6) inhibited RL95-2 cell invasion. However, anti-CD9 mAb continued to show a stimulatory effect on RL95-2 cell invasion after treatment with anti-integrin alpha(3) mAb. In contrast, the anti-CD9 mAb had no effect after treatment with the mAb for integrins alpha(6) and beta(1). These findings indicate that CD9 is involved in regulating the invasive properties of endometrial carcinoma cells and that this effect is partially mediated by integrin subunits alpha(6) and beta(1). Thus, CD9 appears to be involved in the prevention of endometrial cancer invasion.

Adult↗
PubMed2000

Null mutation of PCLN-1/Claudin-16 results in bovine chronic interstitial nephritis.

Inherited chronic renal diseases are associated with failures in glomerular filtration and tubular resorption. Such failures invariably result from defects in selective filtration and absorption in surface renal epithelium. Recently, we described an autosomal recessive chronic interstitial nephritis with diffuse zonal fibrosis (CINF) in cattle. Bovine CINF, characterized by increased blood urea nitrogen, creatinine, and urinary proteins, leads to lethality before puberty, usually within the first 6 months or year of life. Here, we demonstrate that the first four exons of PCLN-1/Claudin-16 (CL-16), which encodes a member of the claudin family of tight junction proteins, were deleted in CINF-affected cattle. CL-16 was expressed preferentially in kidneys of normal cattle, but transcripts were totally absent in affected offspring. This observation suggests that the lack of CL-16 protein contributes to the dysfunction of paracellular renal transport systems.

Amino Acid Sequence↗
PubMed2000

HEAT repeats associated with condensins, cohesins, and other complexes involved in chromosome-related functions.

HEAT repeats correspond to tandemly arranged curlicue-like structures that appear to serve as flexible scaffolding on which other components can assemble. Using sensitive sequence analysis techniques we detected HEAT repeats in various chromosome-associated proteins, including four families of proteins associated with condensins and cohesins, which are nuclear complexes that contain structural maintenance of chromosome (SMC) proteins. Among the proteins detected were the XCAP-D2 and XCAP-G subunits of the Xenopus laevis 13S condensin complex, the Aspergillus BimD and Sordaria macrospora Spo76p proteins, the budding yeast Scc2p protein, and the related Drosophila transcriptional activator Nipped-B. Clathrin adaptor and COP-I coatomer subunits, which function in vesicle coat assembly and were previously noted to share weak sequence similarity to condensin subunits, also contain HEAT repeats. HEAT repeats were also found in the TBP-associated TIP120 protein, a global enhancer of transcription, and in the budding yeast Mot1p protein, which is a member of the SWI2/SNF2 family. SWI2/SNF2 proteins, some of which are helicases, perform diverse roles in transcription control, DNA repair, and chromosome segregation and form chromatin-remodeling complexes. HEAT repeats also were found in dis1-TOG family and cofactor D family microtubule-associated proteins, which, owing to their roles in microtubule dynamics, perform functions related to mitotic progression and chromosome segregation. Hence, our analysis predicts structural features of these proteins and suggests that HEAT repeats may play important roles in chromosome dynamics.

Amino Acid Sequence↗
PubMed2000

Increase in 8-hydroxyguanine and its repair activity in the esophagi of rats given long-term ethanol and nutrition-deficient diet.

Epidemiological studies have shown that an increased risk of esophageal cancer is associated with the chronic consumption of alcoholic beverages, although alcohol itself is not a carcinogen in animal models. Reactive oxygen species produced by the metabolism of ethanol or by chronic inflammation may play an important role in the carcinogenic process. In this study, we analyzed one type of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), and its repair activity in the esophagus as indicators of cellular oxidative stress in rats given long-term ethanol and an autoclaved diet (nutrition-deficient diet). Three-week-old male Sprague-Dawley rats were fed an ethanol beverage whose concentration was increased from 12 to 70% over 20 weeks. When the concentration reached 50%, the diet of one group was changed from the regular diet to an autoclaved diet. At the feeding periods of 20, 25, 30, and 35 weeks, the rats were sacrificed and the 8-OH-Gua levels and repair activities within the esophagi were measured. After 30 weeks of ethanol- and autoclaved diet-feeding, significant increases of 8-OH-Gua and its repair activity were observed in the esophagi, but not in those of the ethanol- and normal diet-fed rats. This result indicates that the combined effects of long-term ethanol consumption and nutritional deficiency may be involved in inducing oxidative stress in the rat esophagus.

Animals↗
PubMed2000

Human tissue distribution of TA02, which is homologous with a new type of aspartic proteinase, napsin A.

The N-terminal amino acid sequence of TA02 (molecular weight 35.0 kDa, isoelectric point 5.29), which is associated with primary lung adenocarcinoma, was determined and a fragment peptide was used to generate mouse monoclonal antibodies (mAbs) against TA02. The amino acid sequence suggested that TA02 might be homologous with napsin A, a new type of aspartic proteinase. In this context, we confirmed the expression of napsin A in primary lung adenocarcinoma using reverse-transcription polymerare chain reaction (RT-PCR) and showed that the TA02 mAbs reacted with glutathione-S-transferase (GST)-napsin A fusion protein. We concluded that TA02 is the same molecule as napsin A, and showed immunohistochemically that it is distributed mainly in type II pneumocytes, alveolar macrophages, renal tubules and exocrine glands and ducts in the pancreas. In particular, type II pneumocytes and alveolar macrophages showed high expression of TA02 among human normal tissues. In primary lung adenocarcinoma, 47 out of 58 (81.0%) primary lesions were positive. All well-differentiated adenocarcinomas except those of goblet cell type showed high expression of TA02. In addition, two out of seven (28.6%) large cell carcinomas showed low expression of TA02. The other histopathological types of primary lung cancer did not express TA02 at all. A few cases of renal cell cancer, pancreatic cancer, breast cancer, thyroid cancer, colon cancer and ovarian cancer showed low expression, but the staining patterns were completely different from that of primary lung adenocarcinoma, which showed a granular staining pattern. Our novel mAbs should be valuable for immunochemical detection of TA02/napsin A.

Adenocarcinoma↗
PubMed2000

Analyses of oxidative DNA damage and its repair activity in the livers of 3'-methyl-4-dimethylaminoazobenzene-treated rodents.

We measured the levels of 8-hydroxyguanine (8-OH-Gua) and its repair activity in the livers of the Donryu rat, the carcinogen-resistant DRH rat, and the ddy mouse, which were fed a 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB)-containing diet. In a short-term rat experiment (maximum 2 months), 3'-MeDAB did not increase the 8-OH-Gua levels in the livers of the two rat strains, although it significantly increased the repair activity in only the Donryu rat liver at 1 and 2 months. After long-term 3'-MeDAB administration to the ddy mouse (8 months), the levels of 8-OH-Gua and its repair activity were increased in the liver by 3.6-fold and 1.6-fold, respectively. These experiments suggest that 3'-MeDAB increases 8-OH-Gua generation in rodent liver DNA and the 8-OH-Gua repair assay is a reliable marker of cellular oxidative stress induced by carcinogens.

Animals↗
PubMed2000

Photodynamic therapy for experimental tumors using ATX-S10(Na), a hydrophilic chlorin photosensitizer, and diode laser.

ATX-S10(Na), a hydrophilic chlorin photosensitizer having an absorption maximum at 670 nm, is a candidate second-generation photosensitizer for use in photodynamic therapy (PDT) for cancer treatment. The effectiveness of PDT using ATX-S10(Na) and a diode laser for experimental tumors was evaluated in vitro and in vivo. In-vitro PDT using ATX-S10(Na) and the diode laser showed drug concentration-, laser dose- and drug exposure time-dependent cytotoxicity to various human and mouse tumor cell lines. In Meth-A sarcoma-implanted mice, optimal PDT conditions were found where tumors were completely eliminated without any toxicity. Against human tumor xenografts in nude mice, the combined use of 5 mg / kg ATX-S10(Na) and 200 J / cm(2) laser irradiation 3 h after ATX-S10(Na) administration showed excellent anti-tumor activity, and its efficacy was almost the same as that of PDT using 20 mg / kg porfimer sodium and a 100 J / cm(2) excimer dye laser 48 h after porfimer sodium injection. Microscopic observation of tumor tissues revealed that PDT using ATX-S10(Na) and the diode laser induced congestion, thrombus and degeneration of endothelial cells in tumor vessels, indicating that a vascular shutdown effect plays an important role in the anti-tumor activity of PDT using ATX-S10(Na) and the diode laser.

Animals↗
PubMed2000

In vitro plasma protein binding and cellular uptake of ATX-S10(Na), a hydrophilic chlorin photosensitizer.

ATX-S10(Na), a hydrophilic chlorin photosensitizer having an absorption maximum at 670 nm, is a candidate second-generation photosensitizer for photodynamic therapy (PDT) for cancer treatment. In this study, we examined plasma protein binding, cellular uptake and subcellular targets of ATX-S10(Na) in vitro. Protein binding ratios of 50 microg / ml ATX-S10(Na) in rat, dog and human plasma were 73.0%, 87.2% and 97.7%, respectively. Gel filtration chromatography revealed that 1 mg / ml ATX-S10(Na) bound mainly to high-density lipoprotein (HDL) and serum albumin at the protein concentration of 0.4%, with binding ratios of 46% and 36%, respectively. The free form of ATX-S10(Na) was mostly incorporated into T.Tn cells, and its cellular uptake was partially but significantly inhibited by endocytosis inhibitors such as phenylarsine oxide, chloroquine, monensin and phenylglyoxal, and by chilling the cells to 4 degrees C. However, ouabain, harmaline, sodium cyanide, probenecid and aspartic acid did not influence the uptake of ATX-S10(Na), suggesting that cellular uptake of ATX-S10(Na) was not related to sodium-potassium pump activity, sodium-dependent transporter activity, mitochondrial oxidative respiration, organic anion transporter activity or aspartic acid transporter activity. By fluorescence microscopy, lysosomal localization of ATX-S10(Na) was observed in T.Tn cells. However, electron microscopic observation revealed that many subcellular organelles such as mitochondria, endoplasmic reticulum, ribosomes, Golgi complex and plasma membrane were damaged by PDT using 25 microg / ml ATX-S10(Na) soon after laser irradiation at 50 J / cm(2), and tumor necrosis was rapidly induced. This result indicated that ATX-S10(Na) was widely distributed within the cell.

Animals↗
PubMed2000

Induction of specific immunoglobulin A and Th2 immune responses to P6 outer membrane protein of nontypeable Haemophilus influenzae in middle ear mucosa by intranasal immunization.

Nontypeable Haemophilus influenzae (NTHI) is a major pathogen of otitis media. One of the outer membrane proteins of NTHI, P6, is an antigen common to all strains and is considered as a candidate for mucosal vaccine. To elucidate the possibility of developing a nasal vaccine against nontypeable Haemophilus influenzae (NTHI) and to investigate mucosal immune responses in the middle ear, mice were immunized intranasally with the P6 outer membrane protein of NTHI, and P6-specific immune responses in the middle ear mucosa were examined. Mice were given with P6 and cholera toxin intranasally as an adjuvant on days 0, 7, and 14 and were killed on day 21. The P6-specific immunoglobulin A (IgA) antibody titer in ear wash was significantly elevated. Mononuclear cells were isolated from middle ear mucosa, and an increase in P6-specific IgA-producing cells was shown with an enzyme-linked immunospot assay. In addition, an increase in memory T cells in middle ear mucosa was detected with flow cytometric analysis after intranasal immunization. Moreover, in vitro stimulation with P6 resulted in proliferation of purified CD4(+) T cells from immunized mice, and these T cells expressed Th2 cytokine mRNA. These results indicate that P6-specific IgA-B-cell immune responses and selected Th2 cytokine expressing Th cells were induced in middle ear mucosa by intranasal immunization. These findings suggest that a nasal vaccine is useful for preventing otitis media with effusion.

Administration, Intranasal↗
PubMed2000

Role of Gab1 in heart, placenta, and skin development and growth factor- and cytokine-induced extracellular signal-regulated kinase mitogen-activated protein kinase activation.

Gab1 is a member of the Gab/DOS (Daughter of Sevenless) family of adapter molecules, which contain a pleckstrin homology (PH) domain and potential binding sites for SH2 and SH3 domains. Gab1 is tyrosine phosphorylated upon stimulation of various cytokines, growth factors, and antigen receptors in cell lines and interacts with signaling molecules, such as SHP-2 and phosphatidylinositol 3-kinase, although its biological roles have not yet been established. To reveal the functions of Gab1 in vivo, we generated mice lacking Gab1 by gene targeting. Gab1-deficient embryos died in utero and displayed developmental defects in the heart, placenta, and skin, which were similar to phenotypes observed in mice lacking signals of the hepatocyte growth factor/scatter factor, platelet-derived growth factor, and epidermal growth factor pathways. Consistent with these observations, extracellular signal-regulated kinase mitogen-activated protein (ERK MAP) kinases were activated at much lower levels in cells from Gab1-deficient embryos in response to these growth factors or to stimulation of the cytokine receptor gp130. These results indicate that Gab1 is a common player in a broad range of growth factor and cytokine signaling pathways linking ERK MAP kinase activation.

Adaptor Proteins, Signal Transducing↗