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Biomedical subjects

T Hibi

Publications and source records attributed to T Hibi.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Effect of serum factors on the differentiation of a colon cancer cell line Caco-2].

A human colon cancer cell line Caco-2 undergoes spontaneous enterocytic differentiation under the standard culture condition. We examined the changes in the proliferative activity of Caco-2 cells during the differentiation, and the effect of serum factors on this spontaneous differentiation. Caco-2 cells cultured in FCS-containing media exhibited the differentiation phenotypes such as dome formation and increase of ALP activity after the 6th day of culture. Cell cycle analysis showed a marked decrease in S phase cell population during the cell differentiation. When Caco-2 cells were cultured in FCS free media, the cell population of S phase remained unchanged during culture period and the differentiation phenotypes were not induced. The addition of FCS to Caco-2 cell cultured in the absence of FCS resulted in the rapid induction of the differentiation phenotypes. These results suggest that differentiation of Caco-2 cells is closely related to the reduction of cell proliferation and requires some factors in FCS.

Animals↗
PubMed1991

Establishment of epithelial cell lines from human and mouse thymus immortalized by the 12S adenoviral E1a gene product.

To understand the role of thymic epithelial cells in the development of immature thymocytes, the establishment and cloning of thymic epithelial cell lines must be required. In the present study, we established human and mouse thymic epithelial cell lines through the immortalization by the transfection of cDNA sequences of adenoviral E1a 12S mRNA. This procedure resulted in the isolation of five stable cell lines (one human cell line and four mouse cell lines). These cell lines were positive in cytokeratin demonstrated by immunohistochemistry. Electron microscopic study revealed that they had bundles of tonofilaments and desmosome-like tight junctions. These findings indicate that the cell lines immortalized by E1a gene have retained the properties of epithelial cells. MHC class II antigens were not expressed on these cell lines. When interferon-gamma was added to the cultured epithelial cell lines, MHC class II antigens were induced in their cytoplasm and on their surface membrane, demonstrated by immunohistochemical and immunofluorescent studies. It is suggested that these stable cell lines from human and mouse thymus might serve a good tool for the further study of thymocytes differentiation and of unknown cytokines derived from thymus epithelium.

Animals↗
PubMed1991

Thymectomy in ulcerative colitis: a report of cases over a 13 year period.

Seventy eight patients with ulcerative colitis were treated by thymectomy combined with conventional therapy. An interim analysis was made after a median follow-up of 40 months in the thymectomized group and after 25 months in 173 from a non-thymectomized group. The percentage of remission periods in the thymectomized group was significantly higher than that in the non-thymectomized group as estimated by the "patient-month" method. Histological examination of the excised thymus revealed hyperplasia of the thymic epithelial cells and/or the formation of lymphoid follicles. Anticolon antibody activity of the serum from the thymectomized patients decreased gradually and disappeared in 5 years or more. "Thymectomy via the suprasternal notch with parasternal incision" which was applied in this study, is simple and not invasive. Therefore, it is recommended that thymectomy should be considered as one of the treatment for patients who are resistant to conventional therapy.

Adolescent↗
PubMed1990

Immunohistochemical study of a monoclonal antibody 115D8 against human milk-fat globule membrane (MAM-6) in some histological types of breast cancer.

An antigen, MAM-6, in human milk-fat globule membranes, was detected with a monoclonal antibody 115D8, in paraffin-embedded sections of 148 cases including human breast cancers and other breast diseases with immunoperoxidase technique. There were some differences on the staining portion in the cells among the different types of breast cancers, although we could not find any differences in intensity of reaction with 115D8 among the different histochemical types of breast cancers. MAM-6 was mainly localized in the apical portion of the cells or the cytoplasms of the papillo-tubular carcinoma. The antigen was chiefly localized in the margin of the cells or cytoplasms of the solid- tubular carcinoma and scirrhous carcinoma. Normal mammary glands, sweat glands and sebaceous glands were reacted with 115D8 but epidermis, esophagus, stomach, small intestines, large intestines, pancreas, liver, lung, kidney, urinary bladder, thyroid, adrenal glands, heart, striated and smooth muscles, spleen, lymphnodes and brain were not reacted with 115D8 in this study. Although the antibody was not sufficient for differential diagnosis among the types of breast cancer, it may be useful to detect the breast cancer.

Antibodies, Monoclonal↗
PubMed1990

EBV utilizes a unique activation pathway for the transformation of human B cells.

EBV growth-transforms primate B lymphocytes and directly causes mono/multiclonal B cell lymphomas in vulnerable hosts. In this report we demonstrate that the degree of B cell transformability is not quantitatively determined at the level of either the saturable, transformation-prerequisite virus receptors or of the actual viral cell entry process. Instead, post-receptor binding events [Na+/H+ exchange, Ca2+ flux, tyrosine phosphorylation of two proteins (55-60/130-140 kd)] were identified as critical determinants of transformability. The presence of competent virus in transformable cells was per se insufficient for transformation: blockade of Ca2+ fluxes (or the antiport) generates virus-loaded cells that express viral genes but remain untransformed. Delayed induction by ionomycin of appropriately sized Ca2+ fluxes ([Ca2+]i greater than 180 less than 400 nM) re-starts transformation processes in EGTA-blocked, virus-loaded cells, perhaps providing a model for the study of virus re-activation. Overall, EBV induces unique cellular activation events different from non-oncogenic lymphocyte mitogens/activators, and, given the oncogenic potential of transformed cells in susceptible hosts, we hypothesize that these events describe a novel oncogenic transformation pathway.

B-Lymphocytes↗
PubMed1990

In vitro anticolon antibody production by mucosal or peripheral blood lymphocytes from patients with ulcerative colitis.

Serum anticolon antibody and in vitro anti-colon antibody production by peripheral blood and mucosal lymphocytes was investigated in patients with ulcerative colitis. The frequency of serum anticolon antibody was 71% in 41 patients with ulcerative colitis, estimated by enzyme linked immunosorbent assay (ELISA) using isolated rat colon epithelial cells. This finding confirms our previous report on the frequency of serum anticolon antibody detected by flow cytometry analysis. The estimated frequencies of IgG anticolon antibody secreting cells were 1.5-12.5/10(6) cells in the colonic mucosa and 0.1-0.5/10(6) cells in peripheral blood, from patients with ulcerative colitis when Epstein-Barr virus (EBV) was used as a B cell polyclonal activator. Poisson analysis of limiting dilution culture showed that about one per 140 IgG cells in the colonic mucosa synthesised anticolon antibody. Two monoclonal IgG antibodies were obtained from EBV transformed anticolon antibody secreting cells by limiting dilution method. One reacted with goblet cells in the intestine, and the other reacted mainly with colonic epithelial cells. These results suggest that heterogeneous anticolon antibodies are present in patients with ulcerative colitis and that colonic mucosa may be the main source of anticolon antibody. Local autoimmune reaction might have an important role in causing the inflammation of colonic mucosa in this disease.

Antibody-Producing Cells↗
PubMed1989

The complete sequence of soybean chlorotic mottle virus DNA and the identification of a novel promoter.

The complete nucleotide sequence of an infectious clone of soybean chlorotic mottle virus (SoyCMV) DNA was determined and compared with those of three other caulimoviruses, cauliflower mosaic virus (CaMV), carnation etched ring virus and figwort mosaic virus. The double-stranded DNA genome of SoyCMV (8,175 bp) contained nine open reading frames (ORFs) and one large intergenic region. The primer binding sites, gene organization and size of ORFs were similar to those of the other caulimoviruses, except for ORF I, which was split into ORF Ia and Ib. The amino acid sequences deduced from each ORF showed only short, highly homologous regions in several of the corresponding ORFs of the three other caulimoviruses. A promoter fragment of 378 bp in SoyCMV ORF III showed a strong expression activity, comparable to that of the CaMV 35S promoter, in tobacco mesophyll protoplasts as determined by a beta-glucuronidase assay using electrotransfection. The fragment contained CAAT and TATA boxes but no transcriptional enhancer signal as reported for the CaMV 35S promoter. Instead, it had sequences homologous to a part of the translational enhancer signal reported for the 5'-leader sequence of tobacco mosaic virus RNA.

Amino Acid Sequence↗
PubMed1989

Concerted generation of Ig isotype diversity in human fetal bone marrow.

The human fetal bone marrow B cell compartment of 14- to 21-wk gestational age was examined phenotypically and with respect to Ig H chain commitment and diversity. A dramatic expansion of fetal marrow B cell pools at 16- to 18-wk gestational age characterizes a rapid and concerted chain of differentiation events. Transiently up to 1/4 of nucleated marrow cells are CD20+/CD21+ cells which begin to express surface Ig other than IgM. Limiting dilution analysis of EBV-infected marrow cells delineated a virtually exclusive commitment to IgM production until 15 wk and the absolute and relative number of these cells were small (approximately 5% of comparable adult values). In parallel to the rapid increase in total B cell pools size, cells committed and able to secrete any of the five Ig isotypes are generated by 16-wk gestational age and by 18 wk the frequencies of these cells rapidly reach levels typical for adult peripheral tissue such as blood or lymph node. Fetal L chain diversity always anticipated that observed in adult serum. In addition to rising pool sizes and diverse IgH expression, EBV transformability is a major variable during this period of B cell development with up to 2/3 of B lineage cells transformable, about half of which are pre-B cells. By 21-wk gestational age transformable pre-B cells have disappeared and (as in adult tissue) approximately 10 to 20% of CD20+ cells are transformable. The rapid, concerted expression of full H chain diversity during a narrow period in fetal development is unique to marrow and implies a lymphopoietic process in a privileged site rather than an immunologic differentiation event. During this event, the relative proportions between the different IgH classes expressed, resembled that found in adult tissue, perhaps suggesting that B cell inherent programming rather than only antigenic forces determine heavy chain choice. The staggered expression, early in postnatal life, of IgH regions 3' of the C mu locus may reflect regulatory functions rather than inherent immaturity of the B lineage.

Adult↗
PubMed1989

Production of human monoclonal anti-basement membrane zone (BMZ) antibodies from a patient with bullous pemphigoid (BP) by Epstein-Barr virus transformation. Analyses of the heterogeneity of anti-BMZ antibodies in BP sera using them.

We established three lymphoblastoid cell lines from a bullous pemphigoid (BP) patient's peripheral blood by means of EBV transformation, which produced human monoclonal anti-basement membrane zone (BMZ) IgG antibodies. A blocking immunofluorescence test using these MAbs, designated 5A, 5E, and 10D, revealed that 5A and 5E recognized the same or a closely associated epitope, but the epitope for 10D was completely different, 18 of 30 BP sera blocked the reactivity of 10D MAb and 17 sera blocked 5E, while 9 sera did not block the staining of either antibody. Immunoblot analysis demonstrated that both 5A and 5E MAbs reacted exclusively with a protein band of approximately 230 kD in normal human epidermal extracts. However, 10D did not show any protein band. 22 of 30 BP sera strongly reacted with the same 230-kD protein, while none of control sera showed such reactivity. These results clearly demonstrated the heterogeneity of anti-BMZ antibodies in terms of epitopes. These MAbs should be useful in future investigations concerning not only the immunopathology but also the biochemial and molecular analyses of the BP antigen.

Aged↗
PubMed1989

Release of the serum immunosuppressive factor by monocytes in patients with Crohn's disease.

We investigated the in vitro immunosuppressive effect of the sera and the culture supernatants of the peripheral blood mononuclear cells obtained from patients with Crohn's disease. Sera from Crohn's disease markedly suppressed the proliferative response of mouse spleen cells, compared with sera from ulcerative colitis, intestinal tuberculosis and normal controls. The culture supernatants of the adherent mononuclear cells from Crohn's disease showed a remarkable suppressive effect (96 +/- 1%), while the culture supernatants of the non-adherent mononuclear cells had no suppressive activity (-10 +/- 16%). The culture supernatants of the adherent and non-adherent mononuclear cells from normal controls had no suppressive activity. The fractionization of the culture supernatants of the adherent cells from the Crohn's disease patients demonstrated that the fractions with high suppressive activity had similar or identical biochemical properties to the serum immunosuppressive fractions which has been reported previously. These results indicate that monocytes may release the serum immunosuppressive factor in Crohn's disease. This factor may contribute to the depression of the immune reactivity in the mucosal lesion and to the persistence of the stimulation of abnormal immune response in the intestinal wall.

Adolescent↗
PubMed1989

[Effect of combined administration of HBs antigen and anti-HBs antibody on induction of anti-HBs antibody production in vitro and in vivo].

It was considered that nonresponsiveness to hepatitis B surface antigen was in part due to a failure in the antigen recognition (i.e., antigens' phagocytosis, processing and presentation by accessory cells). In order to enhance the capture of antigens, we investigated the effect of simultaneous administration of HBs antigen and anti-HBs IgG on antibody responses in vitro and in vivo. As a result, in vitro sensitization of mononuclear cells from anti-HBs-positive subjects with HBs antigen and anti-HBs IgG induced significant amounts of anti-HBs IgG production in 5 of 6 cases, whereas sensitization with HBs antigen alone failed to induce the antibody production in most cases. In vivo administration of HBs vaccine and anti-HBs immunoglobulin to non-responders to the vaccine triggered active anti-HBs antibody responses in 3 of 7 cases in vivo and in 5 of 7 cases in vitro.

Hepatitis B Antibodies↗