PubMed Health⌕ Search

Biomedical subjects

R Goitsuka

Publications and source records attributed to R Goitsuka.

At least 55 records · Page 3Linked to original sources
PubMed1992

Detection of enhancer repeats in the long terminal repeats of feline leukemia viruses from cats with spontaneous neoplastic and nonneoplastic diseases.

Enhancer duplication in the long terminal repeat of feline leukemia virus (FeLV) was examined in primary cells from naturally FeLV-infected cats with various neoplastic and nonneoplastic diseases using the polymerase chain reaction. In all cases, a 170-bp band, corresponding to a standard exogenous FeLV with one copy of enhancer, was detected. Repeated enhancer sequences were found in all 8 cases of thymic-form lymphosarcoma, in some cases of lymphosarcoma of other forms (3/8) and myeloid tumors (2/3), and in only 1 of 6 cases with nonneoplastic diseases. The copy number of FeLV proviruses with a repeated enhancer seemed higher than that of those with one copy of enhancer in 3 cases of thymic form lymphosarcoma. In 5 cases of thymic form lymphosarcoma and in 1 case of erythroleukemia, coexistent FeLVs with double and triple enhancers of different sizes were found. Of the enhancer elements, only the SV40 core binding site was found in all the enhancer direct repeats of these FeLVs. All the provirus clones with single and duplicated enhancer sequences from a single tumor showed mutations or deletions characteristic to that tumor, indicating that enhancer repeats may arise in individual animals after infection with a single virus clone. The present findings indicate that FeLV with enhancer repeats generated in the cat is associated with the induction of neoplastic diseases in natural conditions.

Animals↗
PubMed1992

Elevation of feline interleukin 6-like activity in feline immunodeficiency virus infection.

The involvement of feline interleukin 6 (IL-6)-like activity in polyclonal B-cell activation in feline immunodeficiency virus (FIV) infection was investigated by using the proliferative response of hybridoma cell clone B3B1. Cats spontaneously infected with FIV had hyperimmunoglobulinemia, as shown by increases in the percentage of gamma-globulin and the plasma IgG concentration and decrease in the albumin/globulin (A/G) ratio. Because IL-6 plays an essential role in the differentiation of activated B cells into Ig-secreting cells, we examined the effect of FIV infection on the plasma IL-6 level. Plasma IL-6-like activity was found to be significantly higher in FIV-infected cats than in healthy controls. Peripheral blood mononuclear cells (PBMC) isolated from FIV-infected cats and cultured without any exogenous activators of IL-6 production released more feline IL-6-like activity than cells from healthy controls. This phenomenon was mainly due to the increase in the production of IL-6 by adherent cells such as monocytes/macrophages, but also partly by nonadherent cells. These results indicate that elevation of feline IL-6-like activity is associated with FIV infection and that overproduction of IL-6 may contribute to the polyclonal B-cell activation seen in FIV infection.

Animals↗
PubMed1992

Production of a monoclonal antibody that defines the alpha-subunit of the feline IL-2 receptor.

A mAb, termed 9F23, to feline Con A-stimulated PBMC was prepared to characterize feline IL-2R. 9F23 was identified by FACS studies, which showed that the antigen was expressed at a high density on Con A-induced feline T cell blasts while 9F23 binding was not detected on nonactivated PBMC or the Crandell feline kidney cell line CRFK. Chemical crosslinking of 125I-IL-2 to membrane IL-2Rs on Con A-stimulated feline PBMC under the low-affinity condition resulted in detection of a major 65-kDa band. 9F23 specifically immunoprecipitated the IL-2.IL-2R alpha complex in a cell extract; in contrast, neither anti-human IL-2R alpha H48 nor anti-mouse IL-2R alpha 7D4 reacted with the complex. Moreover, immunoprecipitation with 9F23 of the extract from surface-iodinated Con A-stimulated PBMC showed a major 50-55 kDa band. Furthermore, 9F23 had no effect on either IL-2-driven proliferation of the Con A-stimulated PBMC or IL-2 binding. Finally, the expression of feline IL-2R alpha on Con A-stimulated PBMC was up-regulated by addition of exogenous IL-2. Thus, 9F23 defines an epitope different from the IL-2 binding site on the alpha-subunit of feline IL-2R.

Animals↗
PubMed1992

Proliferative responses of a bovine leukemia virus-infected lymphoblastoid B-cell line by its culture supernatant and cytokines.

The growth-promoting activity in the culture supernatant of bovine lymphoblastoid B-cell lines (BL2M3 and BL312) were examined. BL2M3 cells proliferated well in response to conditioned medium (CM) obtained from BL2M3 and BL312 cell cultures. These BL2M3 and BL312 CM were used as sources of BL2M3 cell growth-promoting factor (BL2M3-GPF). BL2M3-GPF was sensitive to acid (pH 2) and alkali (pH 10) and was heat-labile. Proliferative responses of BL2M3 cells were not induced by human recombinant (r)IL 1, rIL 2, rIL 6, granulocyte-colony stimulating factor (rG-CSF) or tumor necrosis factor (rTNF)-alpha. Human low molecular weight B cell-growth factor (LMW-BCGF) was, however, capable of augmenting the proliferation of BL2M3 cells. BL2M3 cells formed clusters in response to LMW-BCGF, whereas they showed single and discete appearance in the presence of BL2M3-GPF. These results suggested that bovine lymphoblastoid B-cell lines might release and respond to the growth-promoting factor for in vitro proliferation of its own cell line, BL2M3.

Animals↗
PubMed1992

Altered surface antigen expression on peripheral blood mononuclear cells in cats infected with feline immunodeficiency virus.

Expression of CD4, CD8, IL-2 receptor alpha chain (IL-2R alpha), and MHC class II (MHC-II) on peripheral blood mononuclear cells were examined in cats infected with feline immunodeficiency virus (FIV). CD4/CD8 T cell ratio in FIV-infected cats was slightly decreased, as compared with that in specific-pathogen-free (SPF) cats. However, there was no statistical differences between them. The number of circulating IL-2R alpha+ cells in FIV-infected cats was higher than that in healthy cats, whereas induction of IL-2R alpha expression by concanavalin A (Con A) stimulation was depressed in FIV-infected cats. By using two-color cytofluorometry, Con A-induced enhancement of IL-2R alpha expression was found to be reduced in both CD4+ and CD8+ populations in PBMC from FIV-infected cats. The circulating MHC-II+ cells were also increased in FIV-infected cats. Furthermore, the induction of IL-2R alpha expression on PBMC after Con A-stimulation significantly depressed by FIV inoculation in vitro. These results suggest that FIV activates PBMC in vivo via direct and/or indirect mechanisms, leading to the unresponsive state of T cells to further stimuli in vitro.

Animals↗
PubMed1992

Association of tumor-associated antigen on the proliferation of bovine leukemia virus-infected lymphoblastoid B-cell lines.

The association of tumor-associated antigen (TAA) on the proliferation of BLV-infected lymphoblastoid B-cell lines (BL2M3 and BL312) was investigated. Flow cytometric analysis of the expression of TAA with monoclonal antibody (mAb) c143 showed high expression of TAA on the surfaces of BL2M3 and BL312 cells. A large amount of TAA was found in the culture supernatant of BL2M3 and BL312 cells as well as in the lysates of BL2M3 and BL312 cells. Culture supernatant but not lysates of BL2M3 and BL312 cells promoted the growth of either BL2M3 cells or BL312 cells. Furthermore, this growth promoting activity in culture supernatants of BL2M3 and BL312 cells was inhibited in a dose-dependent manner when cultured with mAb c143. These results suggested that TAA may be involved in the growth factor-mediated cell growth of bovine B-lymphoblastoid cell lines expressing TAA on their cell surface.

Animals↗
PubMed1991

Anti-murine IL-6 receptor antibody inhibits IL-6 effects in vivo.

Thrombopoiesis, as well as antibody production, is one of the major events in which interleukin-6 (IL-6) has been reported to be involved. Polyclonal anti-murine IL-6 receptor antibody was prepared to examine the effect of the antibody on these events in IL-6-treated mice. Administration of the anti-mIL-6R antibody inhibited the IL-6-induced increase in the number of platelets. Enhancement of the serum level of DNP-specific antibody by intraperitoneal injection of IL-6 was inhibited completely with simultaneous administration of the anti-mIL-6R antibody. The level of DNP-specific antibody was decreased, even below the basal value, by the higher dose of anti-mIL-6R antibody, indicating its effect also on endogenous IL-6. This work provides evidence that anti-IL-6R antibody inhibits IL-6 function in vivo, and provides an animal model of the therapeutic use of anti-IL-6R antibody for IL-6-related disease.

Animals↗
PubMed1991

Exercise-induced phospholipid degradation in the equine skeletal muscle and erythrocytes.

To understand the pathogenesis of equine exercise-induced myopathies and hemolysis, changes of phospholipid peroxidation products in the equine middle gluteal muscle and erythrocytes following the high-speed treadmill exercise were studied. In the skeletal muscle, the peroxidized phosphatidylethanolamine (PE) were increased at 24 hours after the exercise. The malondialdehydes (MDAs) were also increased as the protein-bound MDAs following exercise. In the erythrocytes, the peroxidized PE were significantly decreased at 24 hours after the exercise. The protein-bound MDAs were significantly increased at 5 min after the exercise and returned to the base values at 24 hours after the exercise. These findings indicate that the PE is more susceptible to in vivo oxidative effects than the other phospholipid classes, and the accumulation of the protein-bound MDAs is considered to play some cytotoxic roles in the equine skeletal muscle and erythrocytes following exercise.

Animals↗
PubMed1991

In situ hybridization for the detection of feline interleukin 1 alpha mRNA on the paraffin-embedded section using biotin-labeled probes.

In situ hybridization (ISH) technique with a biotin-labeled probe was established for detecting feline interleukin 1 (IL-1) alpha mRNA in necropsied specimens. Homology between human IL-1 alpha cDNA used as a probe and feline IL-1 alpha mRNA was confirmed by means of dot blot hybridization using the biotin-labeled probe. Hence, we tried by this biotinylated probe to detect mRNA of IL-1 alpha in paraffin-embedded sections. The following results were obtained for the routine procedures: 1) coating slides with poly-L-lysine and/or heating at 60 degrees C at least for 6 hours gave an excellent result for the adhesion of the tissue sections, 2) 10 micrograms/ml solution of proteinase K treatment for 30 minutes or 50 to 100 micrograms/ml solution of proteinase K treatment for 10 to 30 minutes at 37 degrees C gave the good results in the detection of ISH signal, 3) suitable denaturation time of probes at 70 to 90 degrees C was 5 to 15 minutes, and 4) effective hybridization was obtained by incubation for 24 hours at 4 degrees C, for 18 to 24 hours at 25 degrees C or for 5 to 24 hours at 37 degrees C.

Animals↗
PubMed1990

IL-6 activity in feline infectious peritonitis.

Involvement of IL-6 in the development of vasculitis and polyclonal gammopathy in feline infectious peritonitis (FIP) was investigated, by using the proliferative responses of two IL-6-dependent murine hybridoma cell clones, B3B1 and MH60.BSF-2 cells. A significant IL-6 activity was found in sera and ascitic fluids of cats with FIP, whereas no IL-6 activity was detected in sera from healthy cats. In these FIP cats, IL-6 activity in ascitic fluids was significantly higher than that in sera. Peritoneal exudate cells from FIP cats were also found to release a high level of IL-6 to the culture supernatant. The ascitic IL-6 activity was eluted into the fractions corresponding to the m.w. of 30,000 to 40,000 in gel filtration, and into the fractions at the salt concentration from 0.2 to 0.3 M NaCl in anion exchange chromatography. The level of ascitic IL-6 activity was inversely correlated to serum albumin/globulin ratio in these FIP cats. These findings indicate that IL-6 accumulated in the ascites might leaked into the systemic circulation, and be linked to systemic alterations such as enhanced synthesis of Ig and acute phase proteins.

Animals↗
PubMed1990

Molecular cloning of feline leukemia provirus genomes integrated in the feline large granular lymphoma cells.

Feline leukemia virus (FeLV) is a horizontally transmitted agent of the domestic cat which is known to be associated with wide spectrum of diseases of the hematopoietic system. In the present study, proviral DNAs of FeLV proviruses were examined in the tumor cells of natural killer cell lineage which is very rare in cats. In the chromosomal DNA of the tumor cells, 5 distinct bands corresponding to exogenous FeLV provirus genomes were detected by digestion with EcoRI which does not cut most FeLV isolates. Five clones of pLC1, pLC2, pLC3, pLC4, and pLC5 obtained from the 5 respective bands were analysed by restriction endonuclease mapping and Southern blot hybridization using gene-specific probes of FeLV. The results have clearly demonstrated that pLC4 and pLC5 contained large deletions in the pol and part of gag regions, while the full-length proviruses could be observed in pLC1 and pLC2. Furthermore, pLC3 contained part of a variant FeLV genome having an EcoRI site in its gag region. The molecular clones of defective and variant FeLV in this study may be useful for the further examination of tumorigenesis of large granular lymphoma in the cat.

Animals↗
PubMed1990

Immune mediated skin lesions in a dog with autoimmune hemolytic anemia.

A canine case of Coombs' test positive and antinuclear antibody-negative hemolytic anemia was examined because of the development of skin lesions after 18 months treatment with prednisolone. Histopathological examination of biopsy specimens obtained from skin and oral mucosa revealed the acantholysis, edematous lesions of the stratum basale and mononuclear cell accumulation in the dermis. Deposits of immunoglobulin G and complement factor 3 were detected at the intercellular and dermoepidermal junction by the direct immunofluorescent test. From these results, the case was considered to be an autoimmune disease caused by distinct antibodies against different organs.

Anemia, Hemolytic, Autoimmune↗
PubMed1990

Effect of Toxoplasma lysate antigen (TLA) on feline cytotoxicity against FeLV positive lymphoma cells.

The cytotoxic activities of feline spleen cells treated with Toxoplasma lysate antigen (TLA) were assayed against feline leukemia virus (FeLV)-producing lymphoma. FL74 cells, and xenogeneic target lymphoma, mouse YAC-1 cells. The TLA treatments were performed in vivo alone, in vitro alone, and in vivo plus in vitro, respectively. In vivo plus in vitro treatments with TLA induced a marked augmentation in cytotoxic activity of spleen cells to FL74 cells. The treatment with TLA in vivo alone showed an enhancement of cytotoxic activity but in vitro alone did not. The cytotoxic effects of TLA-treated spleen cells obtained from the cats which had been previously immunized with live FL74 cells were similar to those of spleen cells from non-immunized cats treated with TLA. However, no increase of cytotoxicity was shown in the response to mouse YAC-1 cells regardless of TLA treatments. These results indicated that the in vivo TLA treatment augmented the cytotoxicity of feline spleen cells against FeLV-producing lymphoma cell.

Animals↗
PubMed1989

Feline hybridoma growth factor/interleukin-6 activity.

An assay system was developed to measure feline hybridoma growth factor (HGF)/interleukin-6 (IL-6) activity in biological samples containing many kinds of cytokines by using the proliferation of the newly established mouse-rat hybridoma clone, B3B1. The proliferative response of this B3B1 clone was IL-6-specific, and could not be promoted by other cytokines including IL-1, IL-2, IL-3, and granulocyte-colony-stimulating factor (G-CSF). The anti-human B-cell stimulatory factor 2 (BSF-2)/IL-6 antiserum did not neutralize feline HGF/IL-6 activity in conditioned media prepared from feline con A-stimulated splenocytes and unstimulated alveolar macrophages, indicating antigenic differences between species. Feline HGF/IL-6 was eluted into the fractions corresponding to a molecular weight of 30,000-40,000 in gel filtration, and into the fractions at a salt concentration of 0.2-0.3 M NaCl in anion exchange chromatography. The physicochemical properties of feline HGF/IL-6 were slightly different from those of murine and human IL-6.

Animals↗