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Biomedical subjects

N Watanabe

Publications and source records attributed to N Watanabe.

At least 865 records · Page 48Linked to original sources

[Resistance to antimicrobial agents, hemolytic activity and plasmids in Aeromonas species].

A total of 174 Aeromonas isolates consisting of 100 strains from patients with diarrhea being mainly overseas travellers nd healthy subjects, and 74 strains from environmental sources including foods, fish, fresh water, sea water and river soil collected in the area of Tokyo Metropolis and Kanagawa Prefecture was examined for the antimicrobial resistance, presence of plasmids and hemolytic activity. Almost all the isolates (99.4%) were resistant to aminobenzyl penicillin. The isolation frequency of chloramphenicol- or tetracycline-resistant strain was low. Most environmental isolates of A. hydrophila were resistant to multiple antimicrobial agents. Thirty-seven percent of environmental isolates and 39% of human fecal ones carried plasmids. In environmental isolates, seven A. hydrophila and three A. sobria strains carried 63- to 150-kilobase pair (kb) conjugative R plasmids. Two A. hydrophila strains from both the healthy subject and domestic case with diarrhea carried 58- to 90-kb conjugative R plasmids, respectively. None of the isolates from the feces of overseas traveller's diarrhea carried the plasmid. Irrespective of the sources. A. hydrophila showed the highest hemolytic activity among three Aeromonas species. Eighty percent or more of A. hydrophila isolates were of hemolysin positive. The hemolytic titer of A. hydrophila strains from human feces was higher than that of the strains from environmental sources.

Aeromonas↗

A deletion in the Friend spleen focus-forming virus env gene is necessary for its product (gp55) to be leukemogenic.

To determine the biological significance of the 585-base-pair deletion in the env gene of Friend spleen focus-forming virus (SFFV) encoding a leukemogenic glycoprotein (gp55), we examined the pathogenicity of a constructed mutant SFFV (SFFVDF). In the SFFVDF genome, the env deletion was filled in with the corresponding env sequence of Friend mink cell focus-forming virus, whereas the 6-base-pair duplication and the single base insertion near the 3' terminus of SFFV env remained intact. SFFVDF was nonpathogenic in adult mice. During passage of SFFVDF through newborn mice, we recovered various pathogenic variant SFFVs. Molecular analyses of variant SFFV genome DNAs revealed the presence of a distinct deletion in each env gene, which was similar but not identical to that in the wild-type SFFV env. Starting with the SFFVDF genome DNA, other mutant SFFV genome DNAs were constructed in which the sequence coding for the gp70/p15E proteolytic cleavage site present in the SFFVDF genome was modified by oligonucleotide-directed site-specific mutagenesis to prevent the cleavage. These mutant SFFVs were also nonpathogenic. These results indicate that for the pathogenic activity of gp55, a certain env deletion is necessary which causes production of a gp70-p15E fusion protein with an absence of at least the N-terminal one-third of the p15E-coding region.

Animals↗

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↗

Effects of atrial natriuretic peptide on isolated bovine mesenteric lymph vessels.

The mode of action of atrial natriuretic peptide (ANP) on bovine mesenteric lymphatics was investigated by recording isometric tensions in isolated cylindrical segments. ANP in concentrations from 5 to 30 ng/ml caused dose-related decreases in the rhythm and amplitude of spontaneous contractions. No tachyphylaxis was observed in the ANP-induced responses in lymph vessels. Addition of ANP in a low concentration ranging from 3 to 100 ng/ml produced a dose-dependent relaxation in the lymphatic preparations precontracted by 10(-7) M bradykinin. The ANP-induced relaxation was not modified by pretreatment with 5 x 10(-7) M propranolol, 5 x 10(-7) M atropine, 10(-6) M cimetidine, 5 x 10(-5) M aspirin, or 10(-5) M ouabain. The mechanical rubbing of endothelial cells in the lymph vessels caused no significant effect on the ANP-induced relaxation. The relaxation, however, was significantly reduced by pretreatment with 10(-5) M methylene blue. These results suggest that ANP in a low concentration seems to inhibit lymph transport through a reduction of spontaneous contractions and a marked relaxation of lymphatic smooth muscles in bovine mesenteric lymphatics and that ANP may produce the relaxation through synthesis of guanosine 3',5' cyclic monophosphate, independent of the lymphatic endothelium.

Animals↗

Long-term continuous ambulatory peritoneal dialysis. Mass transfer and nutritional and metabolic stability.

Long-term mass transfer and nutritional and metabolic stability of end-stage renal disease patients maintained on continuous ambulatory peritoneal dialysis (CAPD) continue to be of concern. This study longitudinally monitored 43 Japanese CAPD patients (29 males, 14 females) from three centres within the Tokyo Metropolitan Area for an average period of 15 +/- (SD) 8 months. The mean time for patients on CAPD at study initiation was 18 +/- 15 months. Monitored parameters included urea and creatinine mass transfer coefficients, clearances and blood levels, ultrafiltration, lipid levels, dietary protein intake, and weight. Lipid data were also gathered retrospectively from patient records from the time of CAPD initiation. The results were analyzed using regression growth curve analysis and analysis of variance. Statistically significant linear rises with time were apparent only for the creatinine mass transfer coefficients, although this was not considered clinically significant in terms of changes either in peritoneal creatinine clearances or ultrafiltration. Serum cholesterol levels were found to rise significantly above pre-dialysis levels 11 months after CAPD onset, thereafter returning to levels not significantly above baseline levels. In summary, CAPD provided stable, acceptable treatment over the study period.

Adult↗

Regulation of in vivo expression of Fc receptors for IgE (Fc epsilon R) on murine lymphocytes. I. Detection of Fc epsilon R+ lymphocytes by flow cytometry.

Homologous monomeric IgE was employed in a flow cytometric assay for the detection of IgE Fc receptors (Fc epsilon R) on mouse lymphocytes. The expression of Fc epsilon R in normal BALB/c mice was detected on splenic and circulating lymphocytes, but not on bone marrow cells. The Fc epsilon R expression was observed in B cells with B220, surface IgM, and IgD, but not in T cells. Infection of mice with Nippostrongylus brasiliensis resulted in a marked increase in the expression of Fc epsilon R on splenic B cells. T cells, however, did not express Fc epsilon R even after N. brasiliensis infection. On the other hand, the Fc epsilon R expression on normal B cells decreased after a simple incubation at 37 degrees C for 24 h, while in the presence of IgE this decrease was inhibited. In contrast, B cells stimulated with interleukin 4 display Fc epsilon R with high densities. Interestingly, IgE enhanced the Fc epsilon R expression induced by interleukin 4, suggesting that both interleukin 4 and IgE may be responsible for an increase in the expression of Fc epsilon R on B cells of N. brasiliensis infected mice.

Animals↗

Enhancing effect of C1q on IgG monoclonal antibody binding to hapten.

We have previously demonstrated that IgG antibody binding to microfilariae of Dirofilaria immitis increased in the presence of purified C1q. The present study was designed to examine the mechanism of the C1q effect using a system with an antihapten monoclonal antibody (MoAb) and a hapten as an antigen. Microtiter plates were coated with 4-hydroxy-3-nitrophenyl-acetyl (NP)-bovine serum albumin (BSA), and mouse anti-NP MoAb (IgG) was added in the presence of C1q. The amount of IgG which bound to NP-BSA increased with the addition of C1q (p less than 0.01) when the antibody had both specificity to the antigen and ability to fix C1q. The C1q effect, examined using two anti-NP MoAbs with different affinities, was more apparent with the low-affinity antibody (LAMoAb) than with the high-affinity (HAMoAb; percent enhancement of IgG binding was 19 vs. 12%). The C1q effect on LAMoAb binding was doubled when a small amount of HAMoAb was incubated with LAMoAb. The C1q effect on IgG binding might be operative in the early phase of infection, where a small amount of high-affinity antibody and a relatively large amount of low-affinity antibody are produced in the host.

Adjuvants, Immunologic↗

Interleukin-4 gene expression in high and low IgE responder mice.

Interleukin-4 (IL-4) gene expression in murine spleen cells was examined by stimulation with concanavalin A (Con A). Spleen cells from a DBA/2 strain of mice, a high IgE responder, expressed IL-4 mRNA within 3 h after incubation with Con A. Maximal IL-4 mRNA expression was observed 6-9 h after stimulation. The amount of IL-4 mRNA induced by Con A was greatest in spleen cells obtained from high IgE responder strains of mice. A trace amount of mRNA was induced in spleen cells from low IgE responder (SJL) mice. The amount of mRNA induced in spleen cells from an intermediate IgE responder (C57BL/6) was smaller than that from high responders, but significantly greater than that from low responders. Spleen cells from IgE nonresponders (SJA/9) developed only a negligible amount of IL-4 mRNA after stimulation with Con A. Time course and optimal concentration of Con A for the expression of IL-4 mRNA were essentially the same in high (DBA/2) and low (SJL) responder strains of mice. The decreased expression of IL-4 mRNA in low IgE responder spleen cells upon stimulation was not due to the decrease in Thy-1-positive cells or L3T4-positive cells in the spleen. The results obtained in the present study may indicate that high and low IgE responder traits are determined depending on their levels of IL-4 mRNA expression.

Animals↗

Hepatoprotective compounds from Canarium album and Euphorbia nematocypha.

Successive purification of the extract from Canarium album and Euphorbia nematocypha, guided by antihepatotoxic activity in primary cultured rat hepatocytes, led to the isolation of brevifolin (1), hyperin (2), ellagic acid (3) and 3,3'-di-O-methylellagic acid (4) as hepatoprotective compounds. Compounds 1,3 and 4 also reduced carbon tetrachloride (CCl4)-induced liver damage in mice. The hepatoprotective activities of 1, 2, 3 and 4 in vitro and in vivo are apparently due to their antioxidative effects, which were exhibited by further studies using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and CCl4-induced lipid peroxidation systems.

Animals↗

[Receptor-mediated cancer therapy--tumoricidal cytokines, adoptive therapy of LAK, TIL].

Three modes of receptor-mediated cancer therapy were reviewed presenting our own data. Employment of tumoricidal cytokines (IFN, TNF, LT) to this type of therapy has been expected to be the most promising approach. However, preclinical and clinical results so far obtained, revealed that they were useful only for the very limited diseases including renal cancer or some hematological malignancies. Second approach is to utilize growth factors conjugated with toxin or carzinostatin which are readily internalized into tumor cells. In this context, transferrin-neocarzinostatin was examined in our laboratory both in vitro and in vivo for its anticancer activity and was found to suppress tumor growth more significantly than neocarzinostatin alone on the basis of molar ratio. Thus this approach may be worthy to be clinically investigated. Adoptive therapy of lymphokine activated killer (LAK) or tumor infiltrating lymphocyte (TIL) may also be categorized into receptor mediated cancer treatment since both are activated by signals through IL-2 receptor. Although clinical evaluation is still on going, the therapy appears to be effective only when effector cells are administered locally to tumors.

Humans↗

[Tumoricidal biological response modifiers (BRM)].

TNF, IFN, LT and IL-1 are well-known biological response modifiers (BRM) with cytocidal activity. Whereas carcinostatic agents generally derive their cytocidal action from their direct mutual reaction with target molecules (e.g., DNA, RNA), the cytocidal action of BRM resides in the enzyme response which ensures upon their binding to receptors. Accordingly, concomitant use of these drug of differing mechanism of action has a rationale. Considering that a certain kind of counteracting protein is present in cancer cells which are refractory or resistant to such cytokines, combination therapy with carcinostatic agents with inhibitive activity against such protein is also justified. In the same context the effects of TIL and LAK activated by IL-2 could be enhanced if the immune system should be modulated by combined use of BRM and carcinostatic agents such as CY. This paper discusses the results obtained with BRM and carcinostatic agents in combination in animal models and clinical cases.

Antineoplastic Agents↗

Anti IgE-induced asthma in guinea pigs; a new model for asthma. Physiological and pathological studies.

We established an experimental animal model for IgE-mediated asthma by the use of intravenous injection of rabbit anti guinea pig IgE in normal guinea pigs. The degree of asthmatic airway obstruction was quantitatively estimated by Mead's apparatus which enabled us to use unanesthetized guinea pigs. With the injection of anti IgE, only an early asthmatic response was observed. Inhalation of anti IgE did not trigger asthma. Histo-pathological changes in the lung obtained immediately after the injection of anti IgE resembled those reported in human asthma. This system may be used for pathological and pharmacological studies of the IgE-dependent early asthmatic response.

Animals↗

[Disturbances of visual perception and the lesions on spastic diplegia].

In a study of 12 cerebral palsy with spastic diplegia, the relationship between their disturbances of visual perception and their lesions was discussed. All of them were performed Frostig Developmental Test of Visual perception and Tanaka-Binet Intelligence Test. Six of them showed disturbances of visual perception on Frostig Test. Subtest II, figure-ground, was the lowest of all subtests. The mean of perceptual quotient was under that of intelligence quotient significantly (p less than 0.05 t-test). MRI examination was performed to all and the lesions were detected at 10 of them. Six who showed disturbances of visual perception had the lesions and two who showed good visual perception had no lesions. The lesions were periventricular white matter and extended to semioval center and subcortical white matter at parietal and occipital lobes. Anatomically, their lesions correspond to superior longitudinal bundle and vertical occipital bundle and their bundles have important functions as the pass way of visual perception. Therefore, it was suggested that the disturbances of visual perception detected at spastic diplegia were based on the lesions and the mechanism was disconnection of higher visual pass way.

Brain↗