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Biomedical subjects

A Yachi

Publications and source records attributed to A Yachi.

At least 19 recordsLinked to original sources
PubMed1997

A rapid and simple method to quantify Helicobacter pylori adhesion to human gastric MKN-28 cells.

A rapid and simple method to quantitatively analyse Helicobacter pylori adhesion to human gastric epithelial cells was developed by using an enzyme-linked immunosorbent assay. This method made it possible to quantitatively evaluate the adhesion activities of many different H. pylori strains at a time. Our studies indicate that this method is well suited for the quantitative analysis of H. pylori adhesion to gastric epithelial cells.

Bacterial Adhesion↗
PubMed1996

Quantitative detection of secretory immunoglobulin A to Helicobacter pylori in gastric juice: antibody capture enzyme-linked immunosorbent assay.

Helicobacter pylori is a major etiologic agent in gastroduodenal disorders. In this study, immunoglobulin A (IgA) antibodies to H. pylori were estimated in serum and gastric juice specimens from patients with gastritis and peptic ulcers using antibody capture enzyme-linked immunosorbent assays (ACELISAs). The antibody titers of the ACELISAs are independent of the antibody concentration and reflect the ratio of H. pylori-specific IgA to total IgA. The ratio is stable, although the antibody concentration fluctuates in gastric juice. Using the ACELISAs it was possible to evaluate quantitatively not only serum IgA (SR-IgA) antibodies but also secretory IgA (SC-IgA) antibodies in gastric juice. There were significant differences between the patients and control group in the SR-IgA and SC-IgA ACELISAs. Furthermore, the ACELISAs made it possible to compare between SR-IgA antibodies in serum and SC-IgA antibodies in gastric juice. In all patients, the ratios of H. pylori-specific IgA were higher in gastric juice than in serum. These results suggest that H. pylori SC-IgA antibodies are mainly produced by the local immune response in the gastric mucosa. Our studies indicate that ACELISA is well suited for the analysis of local immune response in mucosa.

Adult↗
PubMed1996

Expression of CD10/neutral endopeptidase in normal and malignant tissues of the human stomach and colon.

The expression of common acute lymphoblastic leukemia antigen (CALLA; CD10), which is identical to neutral endopeptidase (NEP, EC3.424.11), was examined in the malignant and adjacent noninvaded tissues of the human stomach and colon (n = 27). All of 27 normal and 18 well or moderately differentiated adenocarcioma tissue specimens were positive for monoclonal antibody (mAb) NL-1 against CD10/NEP, whereas the expression level was clearly decreased in all of 9 specimens of poorly differentiated adenocarcinoma. In addition, all of 7 gastric or colorectal carcinoma cell lines tested showed decreased expression of CD10/NEP. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis of the crude antigen J5 from the normal colon tissue lysate by mAb J5 detected a single band of approximately 100 kDa that was consistent with that of NALM-6 cells used as a positive control. These findings suggest that CD10/NEP is expressed in normal epithelial cells of the human stomach and colon, whereas the expression level is decreased in the poorly differentiated type of adenocarcinoma.

Adenocarcinoma↗
PubMed1996

Gastric antral vascular ectasia causing severe anemia.

Gastric antral vascular ectasia (GAVE) that caused continuous gastrointestinal bleeding is reported in a 76-year-old woman who had been treated with repeated blood transfusions because of severe anemia. Endoscopic examination was performed and diffuse speckled telangiectasia of the entire antrum was observed. Laboratory data showed SGOT > SGPT, decreased chE level and the increased levels of serum gastrin and ICG at 15 min. Anti-HCV antibody was positive. Image examination revealed splenomegaly. There was no family history of telangiectasia, and no telangiectasia was found in other organs. The diagnosis was established as GAVE with liver cirrhosis. Surgical resection of the distal stomach resulted in termination of the bleeding, and the cirrhotic changes of the surface of the liver were revealed at that time, providing further evidence of liver cirrhosis. Although the pathogenesis of GAVE is unknown, liver cirrhosis and hypergastrinemia are thought to be associated with the condition. Importantly, this condition is a cause of severe gastrointestinal bleeding in elderly patients.

Aged↗
PubMed1996

Subcapsular hematoma of the liver and pylethrombosis in the setting of cholestatic liver injury.

We describe a subcapsular hematoma of the liver and pylethrombosis in a patient who developed cholestasis 4 days after severe burn injury. On the 44th hospital day, severe anemia suddenly appeared with no determinable cause. This was the initial manifestation of hepatic hematoma. Cholestatic liver injury of unknown cause lasted throughout the clinical course. The patient subsequently died of hepatic failure 27 months after the burn injury. An autopsy confirmed pylephlebitis and pylethrombosis, which were considered to have contributed to the hepatic failure. This was a rare case of hepatic hematoma and pylephlebitis and pylethrombosis that developed after burn injury.

Aged↗
PubMed1995

IL-2-induced gene expression of protein-tyrosine phosphatase LC-PTP requires acidic and serine-rich regions within IL-2 receptor beta chain.

A protein-tyrosine phosphatase LC-PTP is preferentially expressed in hematopoietic cells and is an early response gene in lymphokine stimulated cells. Here, we found the LC-PTP mRNA induction by IL-2 was markedly inhibited by several tyrosine kinase inhibitors. The induction required both the acidic and serine-rich regions of the IL-2 receptor beta chain (IL-2R beta) in mouse IL-3-dependent pro-B BAF-B03 transfectants. This is strikingly different from the induction of c-myc gene expression, which requires the serine-rich region alone. In addition, overexpression of activated-Lck or -Raf kinases resulted in augmented LC-PTP mRNA expression in myeloid cell line 32D transfectants. Considering the previous findings that the acidic region of the IL-2R beta is responsible for association with Lck and activation of Raf kinase, IL-2-induced expression of LC-PTP mRNA may be primarily transduced through a Lck-Raf mediated signaling pathway.

Animals↗
PubMed1995

Expression of matrix metalloproteinase matrilysin (MMP-7) was induced by activated Ki-ras via AP-1 activation in SW1417 colon cancer cells.

The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metalloproteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells.

Choline O-Acetyltransferase↗
PubMed1995

Topographic study of Helicobacter pylori and HLA-DR antigen expression on gastric epithelium.

Helicobacter pylori and HLA-DR antigen expression on gastric epithelium, identified by an indirect immunoperoxidase staining method using monoclonal antibodies against H. pylori and HLA-DR antigens, were studied topographically. Fifty-nine biopsy specimens from 41 patients who had neither gastric cancer nor peptic ulcers were examined. H. pylori was observed predominantly over or on the surface epithelium, while HLA-DR antigens were frequently expressed on the epithelium of the isthmus region. These observations led to the conclusion that there was no direct topographic association between H. pylori and epithelial HLA-DR expression. However, the frequency of HLA-DR expression in H. pylori-positive (28/29) specimens was significantly higher than that in H. pylori-negative (18/30) specimens (P < 0.01). Furthermore, a greater number of H. pylori was associated with a stronger expression of HLA-DR antigens (P < 0.001). We conclude that H. pylori is indirectly related to HLA-DR expression on gastric epithelium. H. pylori is the first microbial agent that has been suggested to be associated with epithelial HLA-DR expression in the human gastrointestinal tract.

Adolescent↗
PubMed1995

Lansoprazole versus lansoprazole plus amoxicillin treatment for eradication of Helicobacter pylori in patients with gastric ulcer.

Helicobacter pylori is a major cause of gastritis and an important factor in duodenal ulcer relapse. Eradication of H. pylori has usually been achieved by triple therapy, a combination of bismuth salts and two antibiotics. The disadvantage of these regimens is the large number of tablets and the high incidence of side effects. A new H+,K(+)-ATPase inhibitor, lansoprazole (LPZ), has a strong acid inhibitory effect and an anti-H. pylori effect in vitro. These dual effects have an advantage for the eradication of H. pylori by LPZ alone or by a combination of LPZ and antibiotics. In this study, we investigated an anti-H. pylori effect of LPZ alone and LPZ plus low-dose amoxicillin and the relation between the status of H. pylori colonization and the endoscopic healing stage. LPZ monotherapy suppressed H. pylori but did not eradicate it. LPZ plus low-dose amoxicillin dual therapy eradicated H. pylori in 45.5% of patients with gastric ulcer disease. However, this rate is not satisfactory for eradication therapy. The optimal dosage and duration of treatment need to be specified. A high rate of healing to the endoscopic S2 stage was achieved by eradication of H. pylori and the recurrence of gastric ulcer was suppressed in patients in whom H. pylori was eradicated. The eradication of H. pylori may change the natural course of gastric ulcer disease as it does in duodenal ulcer disease.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Elevation of serum soluble vascular cell adhesion molecule-1 (sVCAM-1) levels in bronchial asthma.

We have previously shown the elevation of serum soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin (sE-selectin) in patients with bronchial asthma during asthma attacks. In the present study, we extended our earlier study by measuring serum sVCAM-1 levels by ELISA in 45 patients with bronchial asthma (23 atopic and 22 non-atopic) during asthma attacks and in stable conditions in order to assess further the state of adhesion molecules in allergic inflammation of bronchial asthma. The levels of sVCAM-1 in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. These findings were observed regardless of atopic status. To examine the regulatory mechanism in the elevation of serum sVCAM-1 levels, serum tumor necrosis factor-alpha (TNF-alpha) levels were measured by ELISA. TNF-alpha levels in sera obtained during bronchial asthma attacks were higher than those in sera obtained in stable conditions. The nature of change in serum TNF-alpha levels correlated with the nature of change in serum sVCAM-1 levels, but serum TNF-alpha levels did not correlate with serum sVCAM-1 levels. These results suggest that higher levels of sVCAM-1 during asthma attacks may reflect the up-regulation of VCAM-1 expression in allergic inflammation, and that a soluble form of VCAM-1 molecules may be useful markers for the presence of allergic inflammation. TNF-alpha is shown to enhance the expression and release of VCAM-1 in vitro, however; the regulatory mechanism in the elevation of serum sVCAM-1 levels remains to be clarified.

Adult↗
PubMed1995

Internal image-bearing anti-idiotypic monoclonal antibodies.

Five anti-idiotypic (Id) monoclonal antibodies (MAbs) (Ab2) were prepared from a BALB/c mouse immunized with anti-carcinoembryonic antigen (CEA) MAb MA208 (Ab1) in a syngeneic system. These anti-Id MAbs appear to recognize unique idiotopes at the combining site of MAb MA208, because they were specifically reactive with MAb MA208 and showed inhibitory activity against the binding of MAb MA208 to CEA. These MAbs were divided into three groups according to the analysis of anti-anti-Id antibodies (Ab3) induced with each anti-Id MAb. Anti-anti-Id MAb M7-625 antiserum (Ab3) reacted with purified CEA in a binding assay and in Western blot analysis, and competed with Ab1 binding to CEA. Furthermore, the binding of anti-Id MAb M7-625 to MAb MA208 was inhibited with CEA, indicating that Ab2 mimics the structure of the epitope in CEA which was recognized with Ab1. These serologic findings suggest that anti-Id MAb M7-625 carries the internal image of the antigen. According to the amino acid sequences of complementarity determining region (CDR) 1, 2 and 3 of the MAb M7-625 variable region, homology of amino acid sequences exists between CDR2 in the H chain (5 amino acids of 10) and domain III of CEA (545-554). Seven anti-Id MAbs were then generated using anti-CEA synthetic peptide MAb P1-356 to analyze further the epitope structure of CEA. These anti-Id MAbs were divided into four groups. Serological analyses as described above suggested that among them, anti-Id MAb M315 had an internal image. We therefore prepared anti-anti-Id MAbs using anti-Id MAb M315. Among them, anti-anti-Id MAb 11B2 reacted directly with CEA and competed with MAb P1-356 in the competition assay. In addition, MAb 11B2 stained both cultured CEA-producing cells and colonic cancer tissues, suggesting that MAb 11B2 is Ab1 like Ab3. These MAbs (Ab1-3) will be of use for the structural analysis of the internal image.

Amino Acid Sequence↗
PubMed1995

Mucosal immune response to Helicobacter pylori and cytotoxic mechanism.

BACKGROUND: Helicobacter pylori is widely accepted as a major pathogen in gastritis. The histologic features of H. pylori gastritis are the numerous infiltrating mononuclear cells (MNCs) and neutrophils. It is not clear what role the infiltrating MNCs and neutrophils play in H. pylori gastritis. METHODS: In this study, we have established enzyme-linked immunospot (ELISPOT) assay for the measurement of H. pylori antibody-producing cells in gastric mucosa. RESULTS: Using ELISPOT assay, we found that H. pylori-specific IgA-producing cells as well as IgG-producing cells were distributed in gastric mucosa. These H. pylori-specific antibodies in gastric mucosa and neutrophils are responsible for the induction of cytotoxic effect to cultured Vero cells. CONCLUSIONS: These observations suggest that a mucosal immune response specific to H. pylori is closely associated with the pathogenesis of gastritis.

Animals↗
PubMed1995

Detection and identification of cagA of Helicobacter pylori by polymerase chain reaction.

AIM: To investigate cagA, which is linked to vacuolating cytotoxin activity of Helicobacter pylori, using molecular techniques. MATERIALS AND METHODS: A polymerase chain reaction method was used to detect cagA from clinical isolates of H. pylori. H. pylori strain diversity was examined by DNA restriction fragment length polymorphism (RFLP) patterns with cagA as a probe. RESULTS: The detection rate of the cagA products was significantly higher in strains from gastric ulcer patients than in those of chronic gastritis patients (78.9 versus 56.0%; P < 0.05), and RFLP patterns were different between gastric ulcer and gastric cancer strains. CONCLUSIONS: A polymerase chain reaction method established for the detection of cagA proved to be rapid and useful. Analysis of cagA may therefore be a useful genetic technique for the study of strain diversity.

Antigens, Bacterial↗
PubMed1994

Expression of MUC1 on myeloma cells and induction of HLA-unrestricted CTL against MUC1 from a multiple myeloma patient.

Polymorphic epithelial mucin (MUC1) was detected in myeloma cells and in sera of multiple myeloma patients. HLA-unrestricted CTL that recognize tumor-associated epitopes on MUC1 has been shown to be induced from breast and pancreas cancer patients. To investigate whether such CTL can also be induced from multiple myeloma patients, an allogeneic mixed leukocyte tumor cell culture was performed. PBMCs of a multiple myeloma patient were stimulated by different allogeneic breast carcinoma and myeloma cell lines. The cultured PBMCs were proliferated and a CTL line TN was established. TN exclusively expressed TCR-alpha/beta, CD3, and CD8. TN lysed breast carcinoma and myeloma cell lines but did not lyse K562, which is sensitive to NK cells. The cytotoxicity of TN was inhibited by anti-CD3 Abs but not by anti-HLA Abs. Thus, the TCR-alpha/beta was considered to be involved in the recognition of the target cells but HLA was not. Furthermore, TN lysed transformed mouse fibroblast cells transfected with MUC1 cDNA, suggesting that this CTL line recognizes MUC1 directly. Thus, it is concluded that precursors of HLA-unrestricted and anti-MUC1 reactive CTL could exist in the peripheral blood of multiple myeloma patients and that myeloma cells can express epitopes on MUC1, which can be recognized by the CTL.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1994

Expression of matrilysin mRNA in colorectal adenomas and its induction by truncated fibronectin.

Matrilysin is believed to have a role in tumor progression. Its expression correlates with the occurrence of colorectal cancer. We have examined the expression of matrilysin mRNA in various colorectal disorders and its localization using RT-PCR and in situ hybridization. We have also examined whether Matrilysin is induced by cell to matrix interaction. Matrilysin mRNA was detected in all adenoma tissues examined, whereas none was detectable in hyperplastic polyps, mildly inflamed regions of ulcerative colitis or normal colon tissues, and its message was localized in adenoma cells themselves. In addition, levels of enzyme activities of matrilysin were lower in adenomas compared with cancers in casein zymography. Matrilysin mRNA was induced by immobilized truncated fibronectin or RGD peptide. Thus, matrilysin may play an important role in colorectal carcinogenesis.

Adenoma↗
PubMed1994

Downregulation of Wilms' tumor gene (wt1) during myelomonocytic differentiation in HL60 cells.

The putative Wilms' tumor-suppressor gene (wt1) encodes a zinc finger DNA binding protein that functions as a transcription repressor. The wt1 gene expression corresponds to kidney development, suggesting a role for this gene in nephroblast differentiation. Here we show that wt1 mRNA expression was downregulated during terminal differentiation of promyelocytic HL60 cells. When HL60 cells were induced to differentiate to granulocytes by dimethyl sulfoxide (DMSO) or retinoic acid (RA), a marked downregulation in the levels of wt1 transcripts was found. The wt1 transcripts were also downregulated in HL60 cells during differentiation to monocytes by vitamin D3 or 12-o-tetradecanoyl-phorbol-13-acetate. Nuclear run-on transcription studies showed the transcriptional rate of wt1 gene was not significantly altered during DMSO-induced granulocytic differentiation, suggesting the downregulation was mostly caused by posttranscriptional modification. Importantly, wt1 transcripts were not significantly altered in K562 cells by treatments with DMSO or RA, which do not induce differentiation of K562 cells. These findings suggest that wt1 gene expression may be downregulated as a differentiation-linked event in HL60 cells.

Base Sequence↗