Search PubMed⌕ Search

Biomedical subjects

A Yachi

Publications and source records attributed to A Yachi.

At least 109 records · Page 6Linked to original sources
PubMed1991

Effect of radiation on the expression of carcinoembryonic antigen of human gastric adenocarcinoma cells.

The changes of antigenic expression of cultured human gastric adenocarcinoma MKN45 cells caused by irradiation were investigated to elucidate the immune responses to localized irradiation. The expression of carcinoembryonic antigen (CEA) showed remarkable increases in the culture supernatant and on the surface of the membrane of irradiated cells. The expression of major histocompatibility complex Class I antigen on the membrane also was enhanced by irradiation. In addition, the irradiated cell groups, when analyzed using a CEA-specific probe, showed remarkable increases in the CEA mRNA. These enhancements increased in the 10-Gy and 15-Gy irradiated populations compared with the 5-Gy irradiated population. These results suggest that the enhancement of expression of CEA by radiation takes place at the CEA gene expression (mRNA) level but not at the protein level.

Adenocarcinoma↗
PubMed1991

Conformational structure of a monoclonal anti-idiotypic antibody to the monoclonal anti-adenocarcinoma-associated carbohydrate antibody YH206.

The mAb AI206 (IgG1) is an anti-Id antibody of mAb YH206 (IgM) to adenocarcinoma-associated carbohydrate Ag and inhibits the reaction of mAb YH206 to YH206 Ag at low concentrations. By Western blot analysis, mAb AI206 only reacted with unreduced mAb YH206, whereas it did not react with reduced mAb YH206. Furthermore, mAb AI206 reacted with IgM subunit (180 kDa), F(ab')2 (110 kDa), and F(ab) (50 kDa) of pepsin-treated unreduced mAb YH206. Thus, mAb AI206 recognized the structure of F(ab) of mAb YH206. The mAb YH206 reacted with unreduced mAb AI206, F(ab')2 (110 kDa), and F(ab) (50 kDa) of pepsin-treated unreduced mAb AI206. It is presumed that mAb YH206 and mAb AI206 recognize each other in an unreduced condition but not a reduced condition. The recognition of such a conformational Id on F(ab) is important. Because mAb YH206 recognized the carbohydrate on YH206 Ag as well as the peptide on mAb AI206, the conformation on F(ab) of mAb AI206 may mimic the carbohydrate structure on YH206 Ag. In fact, YH206 antibody activity was induced in syngeneic mouse serum immunized with mAb AI206. These observations suggest that the internal image of YH206 carbohydrate Ag is preserved within the conformational Id on F(ab) of mAb AI206.

Adenocarcinoma↗
PubMed1991

Preparation and characterization of monoclonal antibodies specific to synthetic peptide of carcinoembryonic antigen.

Monoclonal antibodies (MAbs) were prepared to a synthetic peptide (PI: 119-140 amino acids) in domain 1 of the carcino-embryonic antigen (CEA) molecule. The majority of the amino acids in peptide PI show a hydrophilic character, and similar sequences are repeated in domains I, II and III of this molecule. These MAbs appear to recognize new epitopes of CEA, since representative conventional MAbs to CEA do not show reactivity to synthetic peptide PI. The resulting MAbs were divided into 2 groups; group 1 (MAb PI-706) reacted with peptide PI, but not with purified CEA preparation, while group 2 (MAb PI-234 and PI-255) reacted with either type of antigen, in the immunoblotting assay using purified CEA and in immunostaining of colonic carcinoma tissues. Furthermore, group-1 MAb PI-706 was reactive to purified CEA after treatment with periodate.

Amino Acid Sequence↗
PubMed1991

New assay to detect shedding antigen with use of anti-idiotypic monoclonal antibodies.

Anti-idiotypic (Anti-Id) monoclonal antibodies (MoAbs) against anti-carcinoembryonic antigen (CEA) monoclonal antibody 5B3 (IgG1) were prepared and characterized. Five anti-Id MoAbs recognized the private idiotype of MoAb 5B3. Idiotype mapping suggested that MoAb 5B3 had at least three distinct idiotopes at its antigen combining site. Utilizing the inhibition of idiotype-anti-idiotype interaction with use of anti-Id MoAb T4-305 or T4-212, an immunoassay to detect shedding CEA was established. The results of this inhibition assay correlated with those of double determinant immunoassay and inhibition percentages linearly increased in a CEA concentration-dependent manner. Since it requires only one epitope of a given antigen molecule, this assay could be widely used for detection of shedding antigens, including tumor-associated antigens.

Animals↗
PubMed1991

Co-expression of X-hapten-like antigen and antigen YH206 on mucin molecules.

The asialocarbohydrate antigen YH206 is expressed on adenocarcinoma-associated mucin molecules which lack epitopes of CA19-9 and DU-PAN-2. To further characterize this molecule, the monoclonal antibody BM2 against the affinity-purified antigen YH206 was established. It was demonstrated by an inhibition test that antigen BM2 was an X-hapten-like structure, one of the representative oncodevelopmental antigens. Although the sensitivity of antigen BM2 in sera of stomach and pancreas cancer patients did not appear to be superior to that of antigen YH206, both antigens were complementary to each other resulting in the improvement of sensitivity. Interestingly, double-determinant enzyme immunoassays showed that antigen BM2 and YH206, both having a cryptic nature for neuraminidase, were co-expressed on the same mucin molecule in sera of patients with stomach cancer or liver cirrhosis. These data suggest that mucin molecules in serum might be classified into several groups based on the distribution of tumor-associated epitopes.

Adenocarcinoma↗
PubMed1991

A case of HBs antigen negative fulminant hepatitis with IgM antibody to hepatitis B core antigen persisting more than seven years.

A 33-year old dentist developed fulminant hepatitis. At admission, a test for IgM antibody to hepatitis B core antigen (IgM anti-HBc) was positive, while tests for HBsAg and HBeAg were negative. He was cured of the disease, but in follow-up examinations from 1983 to 1990 IgM anti-HBc was continuously detected with radioimmunoassay while HBsAg and HBV-DNA were absent in the serum. However, HBcAg was found in a biopsied liver specimen and a small quantity of HBV-DNA was detectable by polymerase chain reaction assay. These observation suggest that the continuous detection of IgM anti-HBc without HBsAg in serum is due to persistent HBV infection and HBV replication in the liver.

Adult↗
PubMed1991

A novel enzyme immunoassay for serodiagnosis of Helicobacter pylori infection.

Helicobacter pylori has recently been implicated as an etiologic agent of gastroduodenal disorders. Comparing the antibody to H. pylori in the sera of patients with that of normal controls by Western blot analysis, a unique antibody was detected in the sera of patients, which reacted with the 25-kilodalton antigen of H. pylori. On the other hand, monoclonal antibody CP3 prepared in the authors' laboratory also recognized the 25-kilodalton antigen of H. pylori. Whether the serum antibody of the patient recognized the CP3 antigen purified by monoclonal antibody CP3 was then examined. Western blot analysis showed that the patient's serum reacted strongly with the affinity-purified CP3 antigen. Using monoclonal antibody CP3, an enzyme-linked immunosorbent assay to detect CP3 antibody in sera was established. In patients with chronic gastritis and gastric ulcers, the titer of CP3 antibody was significantly higher than in normal controls and correlated with the histological grade of antral gastritis. The detection of CP3 antibody in sera is useful in the diagnosis of chronic gastritis and gastric ulcer associated with H. pylori infection and also in evaluation of the grade of gastritis.

Animals↗
PubMed1991

Effects of bromocriptine on experimental GH3 cell tumors.

Bromocriptine in concentrations up to 10(-4) M was studied for morphological and endocrinological effects upon the GH3 cell line as well as the GH1 and AtT-20 cell lines. The cells (10(5)/ml) were incubated with RPMI 1640 or in some experiments Dulbecco's Modified Eagle's Medium supplemented with 10% FCS. Bromocriptine was added in concentrations of 10(-4) to 10(-8) mol/L and aliquots of medium were obtained at 2 and 24 hs for the determination of growth hormone and prolactin. Significant reductions in concentrations of growth hormone and prolactin as well as cell number were observed with a concentration of bromocriptine of 10(-4) M at 24 hs. The electron microscopic appearance of GH3 cells treated with 10(-4) mol/L concentrations of bromocriptine for 24 hs demonstrated extensive and marked vacuolization in the cytoplasm which had already appeared 2 hs after treatment with bromocriptine. In bromocriptine-treated (10(-4) mol/L for 24 hs) GH1 cells and AtT-20 cells, the morphologic features were essentially unchanged, compared to the untreated group. Since many previous reports demonstrated a defective dopamine receptor system in GH3 cells, it must be concluded that bromocriptine has an extradopaminergic action which is selectively observed in GH3 cell.

Animals↗
PubMed1991

An ACTH and FSH producing invasive pituitary adenoma with Crooke's hyalinization.

We report on a patient with ACTH and FSH producing invasive pituitary adenoma complaining of cutaneous pigmentation. Elevations in plasma ACTH, beta-endorphin and cortisol levels as well as urinary 17-OHCS and cortisol excretion were found. Serum FSH concentration was just within the upper limit of the normal range, whereas serum LH level was reduced and alpha-subunit level was normal. Roentogenographic examination showed an almost complete loss of sellar floor and destruction of the posterior clinoids and dorsum sella. CT scan and MRI demonstrated an enlarged tumor invasion of the clivus and its extension to the sphenoid sinus. After subtotal removal of the large pituitary tumor, serum cortisol and plasma beta-endorphin levels as well as plasma ACTH concentrations returned to normal and serum FSH levels also remarkably decreased. Histologically, the tumor corresponded to a chromophobe, slightly PAS positive adenoma. These tumor cells exhibited positive immunostaining with antibody to ACTH (1-24), beta-LPH, beta-endorphin and FSH, while immunostaining of the adenoma cells was negative for LH, TSH, GH and prolactin. The immunogold technique also demonstrated ACTH and FSH particles in the secretory granules in the cytoplasm of the adenoma cells. Some of the tumor cells disclosed Crooke's hyalinization and type I microfilament occupied most of the cytoplasm. In the present study, a very rare case of ACTH and FSH producing invasive pituitary adenoma is reported.

Adenoma↗
PubMed1991

Correlated expression of mRNAs of carcinoembryonic antigen and nonspecific cross-reacting antigen genes in malignant and nonmalignant tissues of the colon.

Expression of carcinoembryonic antigen (CEA) and nonspecific cross-reacting antigen (NCA) mRNAs were observed in malignant and nonmalignant colon tissues by Northern blot analysis. CEA mRNA was detected together with NCA mRNA in nine cultured cell lines, with the exception of the lung carcinoma A549 cell line, and in 19 colon tissue specimens, including carcinomas, adjacent noninvaded tissues and adenomas. When we compared the intensity of the hybridization signal for CEA or NCA mRNA among adenomas, carcinomas and adjacent noninvaded tissues, NCA mRNA rather than CEA mRNA was highly expressed in carcinomas compared to adjacent nonivaded tissues. When, however, the relation between the intensities of hybridization signals for CEA and NCA mRNAs were evaluated in five colon carcinoma cell lines and 19 colon tissue specimens, a statistically significant correlation was observed (gamma = 0.462, P less than 0.01). These data suggest that NCA may be more useful as a tumor marker for colon carcinoma than CEA at the level of mRNA, and that transcriptions of the CEA and NCA genes might be regulated by some common mechanisms in malignant and nonmalignant tissues of the colon.

Adenoma↗
PubMed1991

Colonization of Helicobacter pylori in the gastric mucosa of Mongolian gerbils.

Helicobacter pylori was orally inoculated into Mongolian gerbils. The organisms were able to colonize in the gastro-mucosal layer of the gerbils, especially in those gerbils which had mucosal lesions caused by indomethacin treatment. The pathological changes developed by H. pylori infection were restricted to the stomachs, and only slightly inflammatory cells were observed.

Animals↗
PubMed1991

Detection of circulating intercellular adhesion molecule-1 antigen in malignant diseases.

A new monoclonal antibody (MoAb) HA58 (IgG1) was prepared, which recognizes the binding site on the intercellular adhesion molecule-1 (ICAM-1) antigen to the lymphocyte function-associated antigen-1 (LFA-1). The double-determinant immunoassay (DDIA) was established with use of MoAb HA58 and another anti-ICAM-1, MoAb CL207, to detect the soluble, shedding ICAM-1 antigen. Human recombinant interferon-gamma (IFN-gamma) induced not only the expression of cell surface ICAM-1, but also the shedding ICAM-1 antigen in an IFN-gamma concentration-dependent and incubation-time-dependent manner. DDIA was applied to detect the shedding ICAM-1 antigen in the sera of patients with malignant or benign diseases. The incidence of positivity for ICAM-1 antigen in malignant diseases was higher than that in benign diseases or in healthy controls. Furthermore, the sera of cancer patients with liver metastasis showed higher levels of the shedding ICAM-1 antigen. These findings suggest that serum ICAM-1 antigen may be a useful marker to monitor tumor burden in cancer patients.

Adult↗
PubMed1991

Detection of IgM, IgA, and IgG antibodies to preS2 antigen in hepatitis B virus infection.

Antibodies to the preS2 antigen (anti-preS2) of the hepatitis B virus (HBV), including IgA, IgM and IgG classes, were observed in patients with acute and persistent HBV infection. In acute HBV infection, rapid and marked serum IgM and IgA anti-preS2 responses were observed. Antibodies reached a peak of serum activity at about 1-2 months after the onset of clinical symptoms, and both antibodies disappeared from serum at 4 months after. IgG anti-preS2 was detected in the early phase of the illness, then the level of IgG anti-preS2 gradually rose during the recovery phase. In persistent HBV infection, IgG and IgM anti-preS2 were detected in sera where the preS2 antigen was present, and IgM anti-preS2 was significantly higher (p less than 0.05) in HBeAg-positive than in HBeAg-negative patients. These results indicate that an adequate humoral immune response to the preS2 antigen is induced during acute and persistent HBV infection.

Acute Disease↗
PubMed1991

[B-CLL and bcl-2 gene].

Most of human follicular lymphomas (approximately 90% in U.S.A. or approximately 30% in Japan) possess the t(14; 18) chromosome translocation that directly involves the IgH locus on chromosome 14 and the bcl-2 gene on chromosome 18. The t(14; 18) chromosome translocation occurs nearly exclusively at two hot spots, a major breakpoint clustering region (mbr) within the 2nd exon noncoding region and the minor breakpoint clustering region (mcr) within the 3' flanking region of the bcl-2 gene. Here we show that the rearrangement of the bcl-2 gene occurs in a significant fraction (approximately 10%) of B-CLL. All of the rearranged bcl-2 genes were juxtaposed with Ig lambda or Ig kappa genes, implying that the bcl-2 gene is preferentially linked to the IgL genes in CLL.

Base Sequence↗