Biomedical subjects

T Takeuchi

Publications and source records attributed to T Takeuchi.

At least 289 records · Page 16Linked to original sources

PubMed1999

Accelerated rejection of Fas ligand-expressing heart grafts.

The Fas/Fas ligand (FasL) system plays an important role in the induction of lymphoid apoptosis and has been implicated in the suppression of immune responses. Recently, there has been renewed interest in immune privilege, as it was shown that two privileged sites (the eye and testes) constitutively express FasL, which kills lymphoid cells that invade these areas. We have established murine FasL-transgenic mice (B6) under the control of the cardiac alpha-myosin heavy chain promotor, and transplanted FasL-expressing F1(B6 x C3H/HeJ) heart grafts into syngeneic (F1) and allogeneic (C3H/HeJ) recipients. FasL-expressing F1 heart allografts placed in C3H/HeJ recipients as well as FasL-expressing F1 isografts placed in nontransgenic and FasL-transgenic F1 were more rapidly rejected, and their survival was much shorter than that of nontransgenic control F1 allografts placed in C3H/HeJ. Native control and FasL-expressing hearts looked normal in mice up to 8 wk of age on hematoxylin-eosin staining. Control heart allografts undergoing ordinally acute rejection showed moderate focal lymphocyte infiltrates, while FasL-expressing F1 allografts and isografts showed massive hemorrhage, edema, and massive neutrophil infiltration as early as 1 day after transplantation. In conclusion, FasL expression and surgical procedure (ischemia/reperfusion) were synergistic in the induction of accelerated heart graft rejection, while allogenicity was not necessary. It may be necessary to find ways of controlling neutrophilic reaction/apoptosis in infiltrating lymphocytes to use FasL in clinical organ transplantation.

Animals↗

PubMed1999

Further characterization of the human clear cell sarcoma cell line HS-MM demonstrating a specific t(12;22)(q13;q12) translocation and hybrid EWS/ATF-1 transcript.

Only a small number of clear cell sarcoma (CCS) cell lines have been reported, including the cell line HS-MM. In the present study, this cell line, maintained for more than 4 years since establishment, was further characterized by cytogenetic studies, fluorescence in situ hybridization (FISH) analysis, and reverse transcriptase-polymerase chain reaction (RT-PCR). HS-MM cells both in vitro and in vivo exhibited pseudodiploid karyotypes with the specific t(12;22)(q13;q12) translocation. The translocation between chromosomes 12 and 22 was confirmed by FISH analysis and the hybrid EWS/ATF-1 transcript induced by this translocation was detected by RT-PCR. The HS-MM cell line will be useful for further studies of CCS.

Chromosome Aberrations↗

PubMed1999

Relationship between the biodistributions of radioactive metal nuclides in tumor tissue and the physicochemical properties of these metal ions.

This study was undertaken to elucidate the relationship between the biodistribution of radioactive metal nuclides in tumor tissue and its physicochemical properties. Potassium analogs (86Rb, 134Cs, 201Tl) were taken up into viable tumor tissue, although 22Na concentrated in necrotic tumor tissue. 67Ga and 111In were more predominant in inflammatory tissue than in the viable and necrotic tumor tissue. 169Yb and 167Tm accumulated in viable tumor tissue and tissue containing viable and necrotic tumor tissue. 67Ga, 111In, 169Yb and 167Tm were bound to the acid mucopolysaccharide with a mol. wt. of about 10,000 daltons in the tumor tissue. 46Sc, 51Cr, 95Zr, 181Hf, 95Nb, 182Ta, and 103Ru were highly concentrated in inflammatory tissue and were bound to the acid mucopolysaccharides with a mol. wt. exceeding 40,000 daltons. 65Zn and 103Pd concentrated in viable tumor tissue and were bound to the protein in the tissue. The results suggest that the difference in intra-tumor distribution of these elements is caused by a difference in the binding substances (or status) of these elements in the tissues, and the binding substance is determined by physicochemical properties of the elements. We therefore conclude that the biodistribution of radioactive metal ions in tumor tissue is determined by its own physicochemical properties.

Animals↗

PubMed1999

Green Fluorescent Protein As a Cell-Labeling Tool and a Reporter of Gene Expression in Transgenic Rainbow Trout.

: Green fluorescent protein (GFP) has been used as an indicator of transgene expression in living cells and organisms. For testing the utility of GFP in rainbow trout, we microinjected fertilized eggs with four types of supercoiled constructs containing two variants of GFP complementary DNA (S65T and EGFP), driven by two ubiquitous regulatory elements, human cytomegalovirus immediate early enhancer-promoter (CMV) and Xenopus laevis elongation factor 1alpha enhancer-promoter (EF1). Green fluorescence was first observed at 3 days postfertilization, when the embryo was in the mid-blastula stage. Fluorescence could be detected mosaically in various types of embryonic cells and tissues of swim-up fry. Both the percentage of fluorescent cells and the fluorescence intensity of GFP-expressing cells on blastoderms, measured with a microscopic photometry system, were highest in CMV-EGFP-microinjected embryos. We conclude that GFP is capable of producing detectable fluorescence in rainbow trout, and can be a powerful tool as a cell marker and reporter gene for cold-water fish, and that analysis of GFP expression in living cells is useful for characterizing the activity of cis-elements in vivo.

Journal Article↗

PubMed1999

CD95 ligand expression enhances growth of murine renal cell carcinoma in vivo.

The CD95/CD95 ligand (CD95L) system plays an important role in the induction of lymphoid apoptosis and has been implicated in the suppression of immune responses. In this system, two murine CD95L-transfected renca clones and a control renca clone transfected only with the vector were implanted into the subcapsule of the left kidney of Balb/c and Balb/c nude mice. Both CD95L-expressing and control renca clones formed macroscopic tumors in all of the Balb/c and Balb/c nude hosts 14 days after implantation. Growth of tumors of murine CD95L-transfected renca cells was significantly better than that of control renca cells in Balb/c mice, while the growth advantage of CD95L transfectants was not observed in Balb/c nude mice. Lymphocytes underwent apoptosis mainly in the periphery of the CD95L-expressing tumors but not in control tumors grown in Balb/c mice, while lymphocytes undergoing apoptosis were not observed in CD95L-expressing tumors or in control tumors grown in Balb/c nude mice. Neutrophilic recruitment was rarely observed in CD95L-expressing or control tumors. CD95L expressed on renca cells possibly suppressed immune responses against renca tumors by inducing apoptosis of the infiltrating lymphocytes. However, CD95L-expressing renca cells did not form tumors in the renal subcapsule of allogeneic C3H/HeJ mice.

Animals↗

PubMed1999

Sun-exposure- and aging-dependent p53 protein accumulation results in growth advantage for tumour cells in carcinogenesis of nonmelanocytic skin cancer.

Three hundred and sixteen patients with nonmelanocytic skin cancer, including 46 cases of Bowen's disease (BOD), 134 cases of squamous cell carcinoma (SCC), and 136 cases of basal cell carcinoma (BCC), were examined immunohistochemically using monoclonal antibody DO-7 to assess p53 protein accumulation related to sun exposure and ageing, and growth and differentiation of skin cancer and its precursors. The rates of p53 immunostaining of BOD, SCC and BCC were 80.4%, 76.1% and 70.6%, respectively. p53-positive cells were present not only in cancer nests, but also in dysplastic and even morphologically normal epidermis adjoining cancers. Sun exposure was statistically correlated with the p53 immunostaining scores in morphologically normal epidermis of the three skin cancers and in cancer nests of SCC and BCC. The positivity and score of p53 protein often differed significantly among the three types of cancer, especially in regions of dysplasia. Interestingly, differentiation of SCC was correlated with individual p53 scores for dysplasia and cancer nests, especially for dysplasia. BOD, as the precursor of SCC, demonstrated the strongest p53 expression. Furthermore, 12.3% cases with p53 negative cancer nests showed p53-positive reaction in dysplasia and in morphologically normal epidermis. It seems that the accumulation of p53 protein plays a part in precancerous lesions and in the genesis of more highly differentiated types of skin cancer and affects mainly the growth of tumour cells rather than their differentiation. For BCC, however, age was significantly related to p53 expression. Our findings suggest that overexpression of p53 in normal skin and cancer nests of SCC and BCC is significantly related to sun exposure, that the expression of p53 in BCC is an age-dependent process, and that the early accumulation of p53 protein may be a useful predictor for the detection of nonmelanocytic skin cancer.

Adult↗

PubMed1999

DNA polymerase activity in encysting Entamoeba invadens.

Using an axenic encystation system of Entamoeba invadens as a model for E. histolytica encystation, we examined the level of DNA polymerase activity in E. invadens during encystation induced in vitro. We first characterized the DNA polymerase activity of trophozoites of E. invadens, comparing it with that of E. histolytica, and found that the activity of E. invadens was lower than that of E. histolytica at pH 2, 4, and 6 and was higher at pH 8 and 10. The activity of E. invadens was completely inhibited by high concentrations of K(-). Among inhibitors of mammalian DNA polymerases, aphidicolin and N-ethylmaleimide inhibited the activity, but 2',3'-dideoxythymidine-5'-triphosphate did not. Thus, the sensitivity of the E. invadens activity to salt and inhibitors of mammalian DNA polymerases was basically the same as that recorded for E. histolytica in our previous results. The level of DNA polymerase activity in cysts decreased as encystation proceeded as compared with that of trophozoites. The results indicate that encystation is accompanied by a reduced level of DNA polymerase activity, which correlates with the previous finding that nuclear division occurs during cyst maturation in the absence of DNA synthesis.

Animals↗

PubMed1999

Aged Budd-Chiari syndrome attributed to chronic deep venous thrombosis with alcoholic liver cirrhosis.

Budd-Chiari syndrome is a rare disease, but there are many known causes. Recent studies showed that it can be an acquired lesion resulting from thrombosis in some elderly patients. We report a 74-year-old man with Budd-Chiari syndrome attributed to chronic deep venous thrombosis and alcoholic liver cirrhosis. When he was aged 45 years, stasis ulcers of the lower extremities appeared. Cerebral infarction and left hemiparesis occurred at age 71. Ultrasonography, venacavography, and three-dimensional-magnetic resonance imaging on admission demonstrated total obstruction of the inferior vena cava with several massive thrombi and developed collateral vessels. Although the etiology of the thrombosis remained obscure, we made some speculative assumptions that chronic disseminated intravascular coagulation (which is frequently observed in cirrhosis) or hereditary coagulopathy could be involved, from his familial history of thrombotic phenomena and a severe deficiency of clotting inhibitors. Despite the high mortality of untreated Budd-Chiari syndrome reported in previous studies, this patient had been alive for about 30 years from the suspected onset.

Adult↗

PubMed1999

Real-time detection system for quantification of hepatitis C virus genome.

BACKGROUND & AIMS: For diagnosis of hepatitis C virus infection and monitoring of viral load in patients, a highly sensitive and accurate hepatitis C virus quantification system is essential. METHODS: Hepatitis C virus genome was detected by real/time detection system using an ABI Prism 7700 sequence detector (Perkin Elmer Corp./Applied Biosystems, Foster City, CA). RESULTS: As few as 10 copies of the genome were detected, and the quantification range was between 10(1) and 10(8) copies (r > 0.99). This system was 10-100-fold more sensitive than an Amplicor monitor (Roche Diagnostic Systems, Branchburg, NJ). The coefficient of variation values for both intra-assay precision and interassay reproducibility of identifying the genome quantification ranged from 0.37% to 2.00% and 0.88% to 4.66%, respectively. The system could detect the genome in 98% of patients with chronic hepatitis, 95.8% of patients with liver cirrhosis, and 100% of patients with hepatocellular carcinoma who had the antibody to hepatitis C virus, but could not detect the genome in patients without the antibody. CONCLUSIONS: The establishment of a real-time detection system enables more accurate diagnosis of infection and monitoring of viral load in interferon-treated patients via quantification of viral genome.

Carcinoma, Hepatocellular↗

PubMed1999

Semiquantitative evaluation of alpha1A-adrenoceptor subtype mRNA in human hypertrophied and non-hypertrophied prostates: regional comparison.

The main purpose of this study was to compare semiquantitatively the amount of alpha1a-adrenoceptor subtype mRNA in urethral, central and peripheral areas in benign hypertrophied prostates and non-hypertrophied prostate by the competitive reverse transcriptase polymerase chain reaction (RT-PCR) method. Prostates from twenty cases of men with benign prostatic hypertrophy (BPH) and 5 cases of bladder tumor without BPH were obtained for this study. The mRNA was extracted from the urethral, central and peripheral areas of each prostate, and quantitative RT-PCR was performed using the ratio of PCR product of alpha1a-adrenoceptor mRNA/beta2-microglobulin mRNA. The ratio for the central area of the hypertrophied prostate was significantly greater than that for the same area of the non-hypertrophied prostate (p < 0.05). In contrast, the urethral area showed no significant difference between the two prostate conditions. The central area of the hypertrophied prostate showed the tendency to have an increased alpha1a-adrenoceptor mRNA level compared with the urethral area, though no statistical difference was recognized because of the high standard error. Regional differences in the alpha1a-adrenoceptor mRNA in the non-hypertrophied prostate were rarely observed. The present finding demonstrates that the increased alpha1a-adrenoceptor mRNA content found in the hypertrophied prostate (1) was due to that in the central area.

Aged↗

PubMed1999

Is the size aftereffect direction selective?

We investigated whether the size aftereffect (apparent spatial-frequency shift after adaptation to slightly different frequencies) is direction selective; i.e., whether it is stronger for test stimuli moving in the adapting direction than the opposite direction. We used drifting sinusoidal gratings of various spatiotemporal frequencies for both adaptation and test stimuli, and the perceived test frequency was estimated by means of a matching technique with a staircase method. For the purpose of comparison, the post-adaptation threshold elevation was measured in addition to the size aftereffect. The results revealed that the direction of stimuli had no influence on the magnitude of the size aftereffect for a wide range of spatiotemporal frequencies, whereas the post-adaptation threshold elevation showed clear direction selectivity. Although there was a significant direction selectivity for the size aftereffect at low spatial and high temporal frequencies, the selectivity was much weaker than that seen in the threshold elevation data. These findings are discussed in relation to the validity of a unified account of selective adaptation at and above threshold contrast and the notion of the separate processing of pattern and motion information.

Adaptation, Psychological↗

PubMed1999

A histopathological study of the effects of pulsed Nd:YAG laser irradiation on infected root canals in dogs.

The effects of pulsed Nd:YAG laser irradiation during root canal treatment of infected teeth were investigated histopathologically in dogs. One hundred and eight teeth with a single root in 15 healthy adult beagle strain dogs were used in this study. After inducing infected teeth, each root canal was shaped with up to at least a #40 K-file; then, after coating with black ink, the canal was irradiated using the following parameters: 1 W, 30 pps, for 1 and 2 s, and 2 W, 30 pps, for 2 s. The degree of inflammation of the periapical regions at 2, 4, and 8 wk was examined histopathologically by light microscopy. Inflammation of the periapical regions in the laser-treated groups was significantly less than that in the control group at 4 and 8 wk (p < 0.05). These results suggest that pulsed Nd:YAG laser is useful for root canal treatment of infected teeth, if appropriate parameters are selected.

Animals↗

PubMed1999

Overexpression of c-Met protein in human thyroid tumors correlated with lymph node metastasis and clinicopathologic stage.

To examine the expression of c-Met protein in thyroid tumors and the correlation of c-MET protein expression with lymph node metastasis (LNM) and pathological stage, 111 papillary thyroid carcinomas (PTC), including 44 with synchronous LNM, and 117 follicular adenomas (FA) were immunohistochemically examined using dewaxed sections of formalin-fixed, paraffin-embedded tissues. Immunohistochemical results were confirmed by Western blot analysis. For PTC, positive immunostaining was observed in 107 of 111 (96.4%) cases and was diffusely present in either cytoplasm and nucleus, or only cytoplasm or only nucleus of cancer cells at varying intensities. Staining tended to be stronger in the periphery of cancer cell nests. Positive reaction was also found in 44 of 117 (37.6%) cases of FA. However, the extent and intensity of c-Met immunostaining in FA were far less than those in PTC (p < 0.0001). Forty-four PTC cases (39.6%) exhibited LNM, and the extent and intensity of c-Met expression were significantly correlated with both LNM (p < 0.0001) and pathological stage (p < 0.0001). No significant correlation of c-Met expression with age, sex or tumor size was found. Our findings suggest that PTC expresses c-Met protein much more strongly and intensively than does FA, and that strong and intense overexpression of c-Met protein may be an indicator of the presence of lymph node metastasis and advanced pathological stage of papillary thyroid carcinoma.

Blotting, Western↗

PubMed1999

Increased expression of inducible nitric oxide synthase and peroxynitrite in Helicobacter pylori gastric ulcer.

The role of nitric oxide in ulcer formation remains unknown. Accordingly, we assessed local expression of inducible nitric oxide synthase (NOS) and nitration of tyrosine as an indicator of peroxynitrite formation in patients with Helicobacter pylori (HP)-associated gastric ulcers compared with HP-negative ulcers. Biopsy specimens were taken from the ulcer margin and from an area remote from the ulcer portion. Inducible NOS, nitrotyrosine, and macrophage immunoreactivity were assessed immunohistochemically using a labeled streptavidin-biotin method. In HP-positive gastric ulcers, inducible NOS and nitrotyrosine immunoreactivity was frequently observed at active ulcer margins, sometimes in surface epithelial cells as well as in the lamina propria. Occasionally, inducible NOS and nitrotyrosine reactivity were found in areas remote from the lesion in cases of HP-positive ulcer and HP-related gastritis. Macrophages accumulated significantly in the margin of HP-positive ulcers. In HP-negative gastric ulcers, inducible NOS and nitrotyrosine immunoreactivity also were frequent at the ulcer margin, but no significant immunoreactivity was observed at a distance. HP eradication caused significant attenuation in inducible NOS and macrophage immunoreactivity. In conclusion, nitric oxide and peroxynitrite formation is increased in HP-infected gastric mucosa, suggesting that HP promotes nitric oxide stress.

Fluorescent Antibody Technique↗

PubMed1999

jumonji gene is essential for the neurulation and cardiac development of mouse embryos with a C3H/He background.

The recessive mutant mouse jumonji (jmj), obtained by a gene trap strategy, shows neural tube defects in approximately half of homozygous embryos with a BALB/cA and 129/Ola mixed background, but no neural tube defects with BALB/cA, C57BL/6J, and DBA/2J backgrounds. Here, we show that neural tube and cardiac defects are observed in all embryos with a C3H/HeJ background. In addition, abnormal groove formation and prominent flexure are observed on the neural plate with full penetrance, suggesting that abnormal groove formation leads to neural tube defects. We found morphogenetic abnormalities in the bulbus cordis (future outflow tract and the right ventricle) of homozygous embryo hearts. Moreover, myocytes in the ventricular trabeculae show hyperplasia with cells filling the ventricles. Together with the observation that the jmj gene is expressed in the neural epithelium of the head neural plate and in myocytes in the bulbus cordis and trabeculae, the results show that the jmj gene plays essential roles in the normal development of the neural plate, morphogenesis of bulbus cordis, and proliferation of trabecular myocytes on a C3H/He background.

Animals↗

PubMed1999

Inhibition of thermolysin and human alpha-thrombin by cobalt(III) Schiff base complexes.

Cobalt(III) Schiff base complexes have been shown to inhibit the replication of the ocular herpes virus. It is well known that these complexes have a high affinity for nitrogenous donors such as histidine residues, and it is possible that they bind to (and inhibit) an enzyme that is crucial to viral replication. In model studies, we have found that [Co(acacen)(NH3)2]+ is an effective irreversible inhibitor of thermolysin at millimolar concentrations; it also inhibits human alpha-thrombin. Axial ligand exchange with an active-site histidine is the proposed mechanism of inhibition. The activity of thermolysin and thrombin can be protected by binding a reversible inhibitor to the active site before addition of the cobalt(III) complex.

Binding Sites↗

PubMed1999

A facile synthesis of D-glucose-type gem-diamine 1-N-iminosugars: a new family of glucosidase inhibitors.

gem-Diamine 1-N iminosugars of D-glucose-type, a new type of glycosidase inhibitors, have been synthesized from siastatin B, isolated from Streptomyces culture. 2-Trifluoroacetamido-1-N-iminosugar, (2S,3R,4R,5R)-2-trifluoroacetamido-5-hydroxymethylpiperidine -3,4-diol was proved to be a potent inhibitor for alpha-D- and beta-D-glucosidases (IC50 1.9x10(-7) and 4.2x10(-7) M, respectively). 2-Acetamido-1-N-iminosugar, (2S,3R,4R,5R)-2-acetamido-5-hydroxymethylpiperidine-3,4-diol also affected these enzymes (IC50 2.9x10(-6) and 5.4x10(-6) M, respectively).

Aspergillus niger↗

PubMed1999

Characteristic transport of lactoferrin from the intestinal lumen into the bile via the blood in piglets.

Lactoferrin is a major iron-binding protein in milk from several species, such as humans, monkeys, mice and sows. Using neonatal and weaner piglets, the characteristic transfer of lactoferrin from intestinal lumen into bile via the circulation was investigated. Bovine lactoferrin (1 or 3 g/kg body weight) was infused into the stomach through a polyethylene tube or into the duodenum through a duodenal catheter over 5 min. Peripheral blood and bile samples were collected after the infusion. Lactoferrin absorbed into plasma and bile were assayed quantitatively by double-antibody enzyme-linked immunosorbent assay, and homogeneity of bovine lactoferrin in plasma and bile was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting methods. Morphological investigation was carried out according to the peroxidase anti-peroxidase method. Following oral administration in neonatal pigs, bovine lactoferrin appeared in the blood circulation and reached a peak level after 2 h. It was confirmed immunohistochemically that lactoferrin was transported by endocytosis via the epithelial cells. Lactoferrin absorbed into the blood was also detected in the bile and reached a peak value 12 h after oral administration. Transportation of lactoferrin from the intestinal lumen into the bile via the bloodstream was also observed in weaner piglets. Lactoferrin transported into plasma and bile was confirmed to be the same substance as administrated lactoferrin by electrophoresis and immunoblotting methods. Lactoferrin transported into bile was re-absorbed into the blood in neonatal pigs. These results demonstrate that lactoferrin contained in milk is transported into the circulation from the intestinal lumen and excreted into the bile, suggesting the possibility of entero-hepatic circulation of lactoferrin in neonatal pigs.

Administration, Oral↗