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Biomedical subjects

H Takagi

Publications and source records attributed to H Takagi.

At least 343 records · Page 19Linked to original sources
PubMed1997

Investigation of the adducts formed by reaction of butenedioic acids with adenosine.

Several genotoxic butenedioic acids present in chlorine-disinfected drinking water were allowed to react with adenosine, guanosine, and cytidine in aqueous solution. HPLC analyses, with detection at 254 and 310 nm, showed that clearly detectable products were formed only in the reactions with adenosine. The major products from the reactions between either 2-chloro-3-methyl-2-butenedioic acid (ox-MCF) or 2-chloro-3-(chloromethyl)-2-butenedioic acid (ox-CMCF) and adenosine were the same. This substance was isolated by C18 column chromatography and characterized by UV absorbance, 1H and 13C NMR spectroscopy, and mass spectrometry. It was identified as 3-(beta-D-ribofuranosyl)-7-carboxy-7-formyl-8-[9'-(beta-D-ribofuranosyl) -N6- adenosinyl]-1,N6-ethanoadenosine (cf epsilon A,A). The yields of cf epsilon A,A in reactions performed at pH 7.4 and 37 degrees C were 0.7% and 0.3% with ox-MCF and ox-CMCF, respectively.

Adenosine↗
PubMed1997

Histochemical analysis of hyperplastic stomach of TGF-alpha transgenic mice.

Hypertrophic gastric mucosa in transgenic mice overexpressing transforming growth factor (TGF)-alpha showed mucosal cellular hyperplasia with dysplasia, suppression of gastric acid secretion, and chief and parietal cell depletion. In order to clarify the effects of TGF-alpha on the gastric mucosa, we analyzed the stomach of TGF-alpha transgenic mice by mucin histochemical staining and immunohistochemical analysis of TGF-alpha. In transgenic mice, especially those older than 3 months, the fundic gland was notably atrophic but the total mucosa was thickened. The mucous neck cells were hypersecretory and associated with abnormal sulfation. Mucosal hyperplasia was caused by proliferation of surface epithelial cells, associated with formation of intracytoplasmic lumina. The hyperplastic foveolar cells revealed production of a high amount of sialomucin. In addition, the involved stomach regionally revealed collagenous fibrosis in the submucosal layer. The wide distribution of TGF-alpha in the hyperplastic foveolar cells was in sharp contrast to negative expression in the foveolar cells in the control mice. These findings demonstrated the various regulatory functions of TGF-alpha in mucin production, fibrogenesis, and neck cell proliferation in the stomach.

Aging↗
PubMed1997

Fas antigen expression of hepatocytes and its modification by immunosuppressants.

Active cell death induced by ligation of the Fas antigen (Fas-Ag) with its antibody, Fas ligand (Fas-L), has been known to play a major role in cell killing via apoptosis by cytotoxic T lymphocytes (CTL). Thus, in liver transplantation, Fas-Ag expression of hepatocytes and its modification by immunosuppressive agents such as FK 506 or CsA can theoretically influence allograft survival. Mouse hepatocytes (BALB/c) were isolated and cultured with or without FK 506 or CsA, and Fas-Ag expression was determined by flow cytometry. Fas-Ag expression in the control was 17.2 +/- 2.5% after 24 hr of culture. When FK 506 or CsA was added, Fas-Ag expression with FK 506 at a concentration of 0.01-0.1 microg/ml was significantly lower than that with CsA (P < 0.05). When the cells were incubated with apoptosis-inducing anti-Fas-Ag monoclonal antibody, agarose gel electrophoresis of the control cells yielded a typical pattern of DNA fragmentations. The cells with FK 506 at 0.01 microg/ml yielded the least DNA fragmentation. These findings suggested that in the in vivo setting, the hepatocytes of the allograft would have a lower chance of being attacked by CTL in the host treated with FK 506.

Animals↗
PubMed1997

Prediction of effect of interferon on chronic hepatitis C.

Clinical, pathological, and virological analysis including hypervariable region-1 of hepatitis C virus (HCV) was performed to predict the effect of interferon (IFN) on 41 patients with chronic hepatitis type C. The low virus load, low frequency of the mutation in the hypervariable region-1 as the change of amino acid and high level of serum aminotransferase make one estimate the good effect of IFN on patients with HCV. Mutation in the hypervariable region-1 of HCV measured by fast assay fluorescence single-stranded conformational polymorphism was more frequent in nonresponders to IFN than responders. The most frequently mutated position was amino acid number 406. This indicates that the specific mutation site might affect the response of IFN.

Amino Acid Sequence↗
PubMed1997

Lymph node metastasis in carcinoma of the body and tail of the pancreas.

BACKGROUND: There have been no precise reports concerning lymph node metastatic involvement in carcinoma of the body and tail of the pancreas. METHODS: Histopathological examination of lymph node involvement in 30 specimens obtained from patients who underwent pancreatic resection and wide dissection of lymph nodes, including para-aortic lymph nodes, for carcinoma of the body and tail of the pancreas was performed. RESULTS: Fourteen of 30 patients had lymph node involvement. The highest incidence of lymph node involvement was around the splenic artery (five of 30 patients), aorta (four of 30) and coeliac trunk (four of 30). No significant difference in survival rate between the lymph node-negative group and the lymph node-positive group was observed, but all patients in the positive group died within 2 years after surgery, and four patients with para-aortic lymph node involvement died from recurrence within 10 months after surgery. Survival rates were significantly worse in patients with histopathological extrapancreatic nerve plexus invasion, retropancreatic tissue invasion, tumour diameter more than 4 cm, histological portal system vein wall invasion and carcinoma invasion of the surgical margins. CONCLUSION: Although aggressive extended surgery including para-aortic node dissection has been performed, the postoperative survival rate is still low in patients with carcinoma of the body and tail of the pancreas. The high incidence of liver metastasis after surgery is a prime cause of the poor outcome, and effective therapy for postoperative liver recurrence requires evaluation.

Adult↗
PubMed1997

Increased level of circulating adhesion molecules in the sera of breast cancer patients with distant metastases.

The adhesion of circulating cancer cells to the vascular endothelium is an important at step in the hematogenous metastasis of cancer. E-selectin expressed on endothelial cells and carbohydrate ligands expressed on cancer cells mediate this adhesion. We investigated the clinical significance of such cell adhesion molecules in breast cancer. The cytosol concentration of sialyl Lewis(x) was found more elevated in cancerous tissue than that in adjacent non-cancerous tissue. In the serum, sialyl Lewis(x) and soluble E-selectin were seen elevated in patients with advanced and recurrent breast cancer, especially in those with distant metastases. From the above, we have concluded that sialyl Lewis(x) and soluble E-selectin could be used as tumor markers with a close relationship to the metastasis of breast cancer.

Biomarkers, Tumor↗
PubMed1997

Construction of novel subtilisin E with high specificity, activity and productivity through multiple amino acid substitutions.

Through three cumulative amino acid substitutions, we constructed novel mutant subtilisins E of Bacillus subtilis, all with high specificity, activity and productivity. The substitution of conserved Gly127, constituting P1 substrate-binding pocket, with Ala and Val showed a marked preference for the small P1 substrate. Leu was then substituted for Ile31 next to the catalytic Asp32 to enhance the catalytic activity. Both double mutants (I31L/G127A and I31L/G127V) showed a 3-5-fold increase in catalytic efficiency due to a large kcat, without any change in the specificity of the mutants at position 127. Molecular modeling suggests that large P1 residues were unable to access the pocket because of steric hindrance. A third mutation was introduced by replacing Tyr(-1) with Ala in the propeptide essential for autoprocessing to active mature subtilisin in vivo. A prominent 7-20-fold increase in active enzyme production occurred in the triple mutants (Y-1A/I31L/G127A and Y-1A/I31L/G127V).

Amino Acid Substitution↗
PubMed1997

Peritoneal washing cytology combined with immunocytochemical staining and detecting mutant K-ras in pancreatic cancer: comparison of the sensitivity and availability of various methods.

Peritoneal metastases are the second most common site of involvement, following the liver, in pancreatic cancer. Thus, we performed peritoneal washing cytology at laparotomy to diagnose accurately the intraperitoneal spread of carcinoma cells to determine the appropriate therapy. Peritoneal washings were collected at laparotomy from 20 Japanese pancreatic carcinoma patients at Nagoya University Hospital between April 1993 and December 1994. From centrifuged deposits, we examined the cytology by three methods as follows. The first method was conventional cytology, including May-Grünwald and Giemsa, Papanicolaou, periodic acid-Schiff, and Alcian blue. The second method was immunocytochemical staining, using antibodies to carbohydrate antigen (CA19-9) and carcinoembryonic antigen. After extracting DNA from the remaining pellet, we studied the last method, detecting K-ras point mutation, by two-step polymerase chain reaction and restriction fragment length polymorphism analysis. In two cases, peritoneal metastases were macroscopically recognized, and the results of all three methods were positive. In the two other cases, where peritoneal dissemination was not macroscopically recognized, the judgments of conventional cytological study and detecting K-ras point mutation were negative. However, a few malignant cells were found by the immunocytochemical staining method. Judging from their clinical course, the positively stained cells were suggestive of malignancy. At present, the immunocytochemical staining method is the most sensitive of these three methods in peritoneal washing cytology. However, preserving DNA is suitable for repeated examination, and a modified method can be applied. If the sensitivity increases, the method of detecting K-ras has the potential to become the standard for peritoneal washing cytology in pancreatic cancer.

Adult↗
PubMed1997

Neutrophil behavior in pancreas and liver and the role of nitric oxide in rat acute pancreatitis.

The behavior of neutrophils in a rat acute pancreatitis model was observed in the pancreas and liver using fluorescence microscopy with an image analyzing system after labeling with a specific fluorescent reagent. Nonviable cells of both organs were also labeled and quantified. The role of nitric oxide in neutrophil accumulation and organ damage was estimated by administering a relatively selective inhibitor of constitutive nitric oxide synthase, N-nitro-L-arginine (L-NNA). The animal model of acute pancreatitis was induced by cerulein injection (80 mg/kg). Two groups were created, one given and the other not given L-NNA (2.5 mg/kg) prior to the induction of pancreatitis. The number of accumulated neutrophils in the pancreas and liver increased in a time-dependent manner. There was a close relation between the distribution of the neutrophils and inviable acinar cells or hepatocytes. When pretreated with L-NNA, the numbers of accumulated neutrophils and nonviable cells increased significantly in the pancreas. In the liver, a more pronounced accumulation of neutrophils was observed after treatment with L-NNA. Although hepatocyte injury was mild despite the neutrophil accumulation in the control, such injury was marked in the group treated with L-NNA. This suggests that neutrophils serve an important role in exacerbating acute pancreatitis and that nitric oxide provides a defense mechanism against neutrophil accumulation in pancreas and liver.

Acute Disease↗
PubMed1997

Detection of mutant K-ras in dissected paraaortic lymph nodes of patients with pancreatic adenocarcinoma.

In this study, we attempted to detect K-ras point mutations by means of two-stage polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) to diagnose micrometastases in paraaortic lymph nodes of patients with pancreatic adenocarcinoma. Main carcinoma tissues and corresponding lymph nodes in the paraaortic region were obtained from 15 patients who underwent extended radical surgery including the wide dissection of lymph nodes and who were diagnosed as lymph node negative by routine histological examination. DNA was extracted from the tissue specimens, and PCR/RFLP analysis was used to detect K-ras oncogene mutations at codon 12. Thirteen of the primary tumors were found to have K-ras mutations. In eight of the 13 cases, 42 of the 101 lymph nodes showed K-ras point mutations in the paraaortic lymph nodes. These results suggested that PCR/RFLP analysis is potentially highly sensitive for the detection of micrometastases in lymph nodes and that it may be useful in reaching an accurate assessment of the lymphatic dissemination of pancreatic adenocarcinoma at the molecular level.

Adenocarcinoma↗
PubMed1997

Transfer of Bacillus alginolyticus, Bacillus chondroitinus, Bacillus curdlanolyticus, Bacillus glucanolyticus, Bacillus kobensis, and Bacillus thiaminolyticus to the genus Paenibacillus and emended description of the genus Paenibacillus.

We determined the taxonomic status of six Bacillus species (Bacillus alginolyticus, Bacillus chondroitinus, Bacillus curdlanolyticus, Bacillus glucanolyticus, Bacillus kobensis, and Bacillus thiaminolyticus) by using the results of 16S rRNA gene sequence and cellular fatty acid composition analyses. Phylogenetic analysis clustered these species closely with the Paenibacillus species. Like the Paenibacillus species, the six Bacillus species contained anteiso-C15:0 fatty acid as a major cellular fatty acid. The use of a specific PCR primer designed for differentiating the genus Paenibacillus from other members of the Bacillaceae showed that the six Bacillus species had the same amplified 16S rRNA gene fragment as members of the genus Paenibacillus. Based on these observations and other taxonomic characteristics, the six Bacillus species were transferred to the genus Paenibacillus. In addition, we propose emendation of the genus Paenibacillus.

Bacillus↗
PubMed1997

Emended description of Paenibacillus amylolyticus and description of Paenibacillus illinoisensis sp. nov. and Paenibacillus chibensis sp. nov.

The taxonomic position of unidentified group 6 of Bacillus circulans as described by Nakamura and Swezey (L.K. Nakamura and J. Swezey, Int. J. Syst. Bacteriol. 33:46-52, 1983) was determined, and the taxonomy of Paenibacillus amylolyticus was reexamined. The results of PCR amplification of a 16S rRNA gene fragment with a specific primer and comparative analysis of 16S rRNA gene sequences warranted placing the two taxa in the genus Paenibacillus. The levels of DNA reassociation among the strains revealed four groups (designated groups I, II, III, and 6), each with a high level of intragroup relatedness (> 72%). Clustering based on phenotypic characteristics correlated well with DNA relatedness grouping. P. amylolyticus strains were scattered in groups I, II, and III. Strains labeled the type strain of P. amylolyticus from different culture collections appeared in groups I and III. Strains found in group I were identified as P. amylolyticus sensu stricto, and the one strain found in group III was identified as Paenibacillus lautus. Group 6 encompassed strains formerly assigned to B. circulans group 6, and group II contained other strains identified as P. amylolyticus. Groups 6 and II were phenotypically and genetically distinct taxa that were distinguishable from the previously described species. These findings showed that groups 6 and II were new species, for which we propose the names Paenibacillus illinoisensis and Paenibacillus chibensis, respectively.

Bacillus↗
PubMed1997

Alternative splicing of the FHIT gene in colorectal cancers.

In the present study, we examined the status of the FHIT gene in 112 colorectal cancer and 137 colorectal adenoma specimens. In a total of 5 specimens (4 colorectal cancers and 1 colorectal adenoma), a common smaller product was detected in addition to the normal size product. This smaller product had lost exon 4, the 5' noncoding region of the FHIT gene, owing to alternative splicing. Moreover, all of the 5 tumors with alternative splicing were located lower on the rectum than the anterior peritoneal reflection.

Acid Anhydride Hydrolases↗
PubMed1997

Imaging of recurrent intestinal carcinoma with indium-111-labeled anti-carcinoembryonic antigen monoclonal antibody CEA102.

CEA102 is a mouse immunoglobulin G1 monoclonal antibody (mAb) that detects an epitope of carcinoembryonic antigen (CEA). The biodistribution and imaging characteristics of indium-111-labeled (111-In)-mAb CEA102 were studied in 1 primary and 9 extrahepatic recurrent intestinal carcinoma patients. Evaluation included antibody pharmacokinetics and assessment of antibody distribution in surgical specimens, in comparison with whole body imaging using a gamma camera, and imaging with single photon emission computed tomography. Selective mAb CEA102 localization to tumor tissue was demonstrated in 7 patients with tumors over 2 cm in size, and the external images correlated well with the results of surgical inspection, pathological examination, and tissue radioactivity measurements. Tumor:serum ratios ranged from 0.20:1 to 3.22:1, and serial biodistribution study of "regions of interest" also demonstrated a high radioactivity in the tumor. These results indicated the potential exploitability of the 111-In-labeled mAb CEA102 in radioimmunodetection of primary and extrahepatic recurrence of CEA-positive intestinal carcinomas.

Adult↗
PubMed1997

Detection of SRY in 45,X/47,XYY mosaicism leading to phenotypic female.

SRY on the Y chromosome initiates male sex determination. We tested a phenotypic female with sex chromosome mosaicism, X/XYY, for SRY expression. SRY was determined by polymerase chain reaction (PCR) amplification in genomic DNA from a female patient with a sex chromosome mosaic complement, 45,X/47,XYY, followed by sequencing analyses. The patient yielded the PCR product with predicted size and homology to the consensus sequence of SRY. The demonstration of SRY provides evidence that the female phenotype in the presence of sex chromosome mosaicism, X/XYY, may result from alterations in another part of the sex-determining pathway or downstream from SRY.

Adolescent↗
PubMed1997

Significance of tumor necrosis factor microsatellite polymorphism in renal transplantation.

Plasma levels of tumor necrosis factor (TNF) alpha are raised during acute rejection following organ transplantation. Variations in TNF alpha production have been found to be associated with the polymorphism of TNF microsatellite. Therefore, there is a possibility that a transplant recipient with some type of TNF microsatellite can be a high-risk patient of graft rejection. The purpose of this study was to examine whether TNF microsatellite polymorphism is related to acute allograft rejection. We investigated the relation of two microsatellites, TNFa and TNFd, to acute rejection after renal transplantation. Among 189 primary living-related renal transplantations from one haplotype-mismatched and one DRB1-mismatched donor, we analyzed TNF microsatellites of 163 patients whose DNA were available to this study. The frequency of the TNFa9 microsatellite allele was significantly higher in the rejection group compared to the rejection-free group. In contrast, the frequency of TNFd4 was significantly lower in the rejection group compared to the rejection-free group. TNFa9 and TNFd4 showed strong associations with HLA-B35 and B44, respectively. However, the TNF microsatellite locus was more closely related to acute rejection than HLA-B. It was suggested that the analysis of TNF microsatellite polymorphism can provide useful information in predicting prognosis after transplantation.

Biomarkers↗
PubMed1997

Blood supply to the latissimus dorsi muscle and muscle performance during co- or counterpulsatile stimulation for circulatory assist.

For the application of the latissimus dorsi muscle (LDM) to circulatory assist, the muscle is stimulated with co- or counterpulsation during the cardiac cycle. The purpose of this study was to evaluate the blood supply to the LDM and its muscular performance during each respective stimulation. The origin of the LDM was connected to a tension gauge, a potentiometer, and 1 kg of weight in series. The LDM was stimulated at a ratio of 1:1 of heart to muscle contraction for 10 min. Copulsatile stimulation made thoracodorsal arterial flow (TDF) predominant during cardiac diastole. In counterpulsatile stimulation, TDF occurred predominantly during cardiac systole. Between the 2 patterns of stimulation, no significant differences were observed in the mean TDF rate during 1 cardiac cycle. The maximal force, maximal contraction length, and power of the LDM also did not differ significantly. These results suggest that despite the difference of the TDF profile, LDM performance may be comparable between co- and counterpulsatile stimulation for the application of the LDM to circulatory assist.

Analysis of Variance↗