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Biomedical subjects

S Fuyama

Publications and source records attributed to S Fuyama.

At least 19 recordsLinked to original sources
PubMed1999

T-cell lymphoma showing a non-enhancing diffuse white matter lesion with marked brain atrophy.

We report an autopsy case of T-cell lymphoma with diffuse white matter infiltration. Cranial magnetic resonance (MR) images showed atrophy of the brain with a diffuse, non-enhancing, T2-high signal intensity lesion in the cerebral white matter. Intra-axial infiltration of T-cell lymphoma should be considered a differential diagnosis in patients with these MRI findings.

Adolescent↗
PubMed1998

Multiple inflammatory pseudotumors of the liver associated with acute myeloblastic leukemia.

A 26-year-old man, diagnosed with acute myelogenous leukemia had multiple inflammatory pseudotumors (IPT) in the liver. The patient presented complete remission after remission induction therapy, and then showed right upper quadrant discomfort and intermittent fever. An ultrasonography disclosed multiple hypoechoic nodules in the liver. A biopsy of the nodules showed focal liver cell necrosis with scant inflammatory cells, compatible with IPT. After several courses of chemotherapy, the nodules in the liver increased. The second liver biopsy of the nodule showed fibrosis. Multiple IPTs in the liver should be distinguished from abscess and metastatic nodules.

Adult↗
PubMed1992

[A case of acute isolated (Fiedler's) myocarditis diagnosed by histopathological study with rapid unfortunate course].

A 65 year-old-man was admitted to our hospital complaining of orthopnea and precordial oppressive feeling. Chest roentgenogram revealed congestive heart failure. Electrocardiogram revealed acute myocardial infarction-like pattern. Serum enzymes (CPK, GOT, LDH) were slightly elevated, but serum antiviral antibodies were not elevated. Echocardiogram showed severe symmetrical left ventricular (LV) hypertrophy, but there was no abnormality of LV wall motion. He died of progressive heart failure and ventricular fibrillation on the second hospital day. A necropsy was performed within one hour of death. The heart was enlarged (690 g) with both left and right ventricular hypertrophy. The myocardium disclosed a diffuse infiltration predominantly of eosinophilic leucocytes. Histopathological study revealed giant cell formation and granulomatous lesions in the myocardium. There was no overt endocarditis or pericarditis. We concluded that the severe LV hypertrophy was due to myocardial inflammatory swelling. From these findings, we diagnosed this case as acute isolated (Fielder's) myocarditis.

Acute Disease↗
PubMed1991

Effector phenotypes and mechanisms of antitumor immune reactivity of tumor-immunized and tumor-bearing mice in two syngeneic tumors.

By using two different syngeneic tumors, Meth A sarcoma and RL male 1 lymphoma of BALB/c origin, the present study was designed to investigate the subset(s) of T cells mediating in vivo antitumor immune responses and some of the effector mechanisms of in vivo protective immunity in BALB/c mice immunized against tumor or bearing tumor. Spleen cells from the mice immunized against Meth A tumor or bearing Meth A tumor inhibited the growth of Meth A tumor in the Winn assay. In the Meth A-immunized mice, L3T4+ (CD4+) cells played a major role in mediating the inhibitory activity against Meth A tumor growth, whereas in the Meth A-bearing mice, the antitumor protective immunity was mediated by both L3T4+ and Lyt-2+ (CD8+) cells. Spleen cells from the Meth A-immunized or Meth A-bearing mice were not able to generate cytotoxic T lymphocytes (CTL) directed against Meth A tumor after the in vitro restimulation of spleen cells with mitomycin C (MMC)-treated Meth A cells, while fresh spleen cells from the Meth A-immunized or Meth A-bearing mice were able to induce the strong delayed-type hypersensitivity (DTH) responses to Meth A tumor. The DTH response to Meth A tumor was mediated by L3T4+ cells in the Meth A-immunized mice and by both L3T4+ and Lyt-2+ cells in the Meth A-bearing mice. In the similar experiments performed in the RL male 1 lymphoma, the antitumor activity in spleen cells from the RL male 1-immunized or RL male 1-bearing mice depended on Lyt-2+ but not L3T4+ cells in the Winn assay. When spleen cells from the RL male 1-immunized or RL male 1-bearing mice were cultured with MMC-treated RL male 1 cells for 5 days, an appreciable CTL response to RL male 1 tumor was induced. These results suggest that the nature of tumor and/or tumor antigens determines which T cell subset is required to exhibit the protective immunity against tumor and thus the different effector mechanisms could be induced in the different tumor models. Furthermore, these data support the conclusion that antitumor T cell responses are affected by the immune state of host to tumor.

Animals↗
PubMed1989

Experimental autoimmune uveoretinitis (EAU) in rats: isolation of S-antigen, EAU susceptibility of rat strains, genetic control of EAU induction, and effects of cyclophosphamide and irradiation on EAU.

Highly purified S-antigen was isolated from bovine retinas by high performance liquid chromatography (HPLC), and was used to induce experimental autoimmune uveoretinitis (EAU) in various rat strains. Studies were then made of the genetic control of EAU, the effects of cyclophosphamide or irradiation on EAU, and the correlation between the EAU incidence and the serum levels of antibody to S-antigen. Lewis rats were the most susceptible to EAU followed by Wistar rats. F344 rats and BN rats were resistant to EAU. (Lewis X BN)F1 rats and (LBNF1 X Lewis) rats were susceptible to EAU, while (LBNF1 X BN) rats were resistant. These results indicate that susceptibility to EAU was inherited as an autosomal dominant trait. Treatment of rats with cyclophosphamide or irradiation (200 rad/rat) on the day before immunization markedly suppressed EAU development. On the other hand, the same dose of irradiation 7 days after the immunization did not affect the disease induction, yet the antibody levels to S-antigen were very high in the rats. In addition, BN rats resistant to EAU exhibited very high levels of antibody to S-antigen. Therefore, the antibody to S-antigen seems to play a minor role, if any, in the immunopathogenic mechanisms of EAU.

Animals↗
PubMed1989

Experimental autoimmune uveoretinitis (EAU) in rats: abrogation of resistance to the induction and augmentation of the inflammation by pertussis toxin.

The effect of pertussis toxin (PT) on experimental autoimmune uveoretinitis (EAU) induced by immunization with S-antigen was examined in rats. Intravenous administration of PT (2 micrograms/rat) initiated the development of EAU in rats that had been made resistant to the induction of EAU by immunization with S-antigen and complete Freund's adjuvant (CFA). The capacity of PT to promote EAU was also demonstrated by a marked augmentation of the inflammation in EAU eyes of rats susceptible to the induction of EAU. PT was most effective when it was given from the day before to the day after immunization with S-antigen. However the induction of EAU was promoted by the injection of PT even 7 days before and 14 days after immunization. The clinical and histopathological findings of the EAU produced by the additional PT treatment were described and the mechanisms by which PT augmented the induction of EAU were discussed.

Animals↗
PubMed1986

Heterogeneous profiles of a factor that renders neutrophils cytotoxic obtained from a concanavalin A-stimulated spleen cell culture in partial purification process.

Concanavalin A (Con A)-stimulated rat spleen cells were cultured in a serum-free conditioned medium. This culture supernatant contained a certain factor(s) that renders neutrophil cytotoxic for various tumor cells. The factor was tentatively termed neutrophil-activating factor (NAF). Rat NAF was partially purified from the serum-free culture supernatant by using ion exchange chromatography of DEAE-Sephadex A-50, gel filtration of Sephadex G-100, and affinity chromatography of Con A-Sepharose 4B. NAF activity was eluted in broad fractions by the ion exchange chromatography and the gel filtration. Moreover, on the Con A column, some NAF activities were bound to the column, but other activities passed through the column. These results showed the heterogeneity or polydispersity of NAF activity in both molecular size and charge-based separation properties. Monoclonal antibodies were produced by fusing BALB/c myeloma cells (P3-X63 Ag8.653) with spleen cells from syngeneic mice immunized with partially purified NAF (pNAF) obtained from the gel filtration. Absorbent beads which were linked with one monoclonal antibody (ANAF-10) partially absorbed NAF activity from supernatants of a Con A-stimulated spleen cell culture. Further purification of pNAF was performed with the use of affinity chromatography of ANAF-10-linked Sepharose. Through these procedures, the NAF activity was concentrated about 10,000-fold. Heterogeneity of NAF activity, however, did not disappear in even this affinity chromatography. On the other hand, 125I-labeled material of the final product migrated to one major band corresponding with an m.w. of about 20,000 as determined by SDS-PAGE analysis, and NAF activity was detected in the same band.

Animals↗
PubMed1986

Mechanisms of in vivo generation of cytotoxic effector cells against tumor in tumor-bearing mice.

Our previous study showed that spleen cells from BALB/c mice bearing RL male 1 lymphoma inhibited the growth of RL male 1 lymphoma by the Winn-type adoptive transfer assay. Although this antitumor activity was mediated by the T-cell subset manifesting the surface phenotype of cytotoxic T-lymphocytes (CTLs), this antitumor activity of spleen cells was not detected by the in vitro cell-mediated cytotoxicity assay (4-h 51Cr release assay). The present study is concerned with the hypothesis that the maturation of the CTLs directed against RL male 1 may be arrested in spleens of the RL male 1-bearing mice and the differentiation into mature CTLs may occur at the tumor site; i.e., the immature CTLs (activated precytotoxic T-cells) may acquire the killing activity when they contact tumor cells at the tumor site. This report shows that BALB/c mice bearing the progressive RL male 1 lymphoma were able to generate CTLs against RL male 1 in the peritoneal cavities when the mice were inoculated i.p. with the irradiated RL male 1 cells. The cytotoxic activity of the peritoneal exudate cells of the RL male 1-bearing mice appeared 3 to 5 days after i.p. inoculation of the irradiated RL male 1 cells and rapidly decreased on day 7 after inoculation. In addition, spleen cells from the RL male 1-bearing mice after i.p. inoculation of the irradiated RL male 1 cells were not cytotoxic, suggesting a highly localized response. The cytotoxic effector cells induced in the peritoneal cavities consisted of T-lymphocytes and natural killer cells. Both cell types were simultaneously induced in the peritoneal cavities of the RL male 1-bearing mice. The T-cell subset mediating cytolytic activity against RL male 1 was shown to consist of Lyt-1+2+ T-cells which were defined by cytolysis with anti-Lyt-1 or anti-Lyt-2 antibody and complement. On the other hand, the normal BALB/c mice inoculated i.p. with the irradiated RL male 1 cells generated natural killer cells in the peritoneal cavities and spleens but the CTLs were not induced. The results from the present and previous studies suggest that precytotoxic or immature cytotoxic T-cells in spleens of the tumor-bearing mice migrate into the circulation and then mature CTLs develop at the tumor site.

Animals↗
PubMed1985

Inhibition of mouse natural killer cytotoxicity by heparin.

The effect of heparin on mouse natural killer (NK) cytotoxicity was investigated. Heparin greatly inhibited NK activity at a concentration of more than 10 units/ml. Inhibition of NK cytotoxicity was observed only when heparin was present in the reaction mixture of the cytotoxicity assay. The results of kinetic study of NK inhibition and target-effector binding assay proposed the possibility that heparin inhibits NK cytotoxicity after the binding of effector cells to target cells. Dextran sulfate, the heparin analog, which has potent negative charge also had an inhibitory effect on NK activity. Fractionation of heparin on Sephadex A-25 column revealed the parallelism of the negative charge and the inhibitory effect of heparin on NK cytotoxicity. These results demonstrated that polyanion could modulate NK cytotoxicity.

Animals↗
PubMed1985

Characterization of effector cells mediating antitumor activity in spleen cells of tumor-bearing mice.

Antitumor activity of spleen cells from BALB/c mice bearing RL male 1 lymphoma was studied. In the Winn assay spleen cells of the tumor-bearing mice inhibited the growth of RL male 1 lymphoma. This antitumor activity of spleen cells was not detected by the in vitro cell-mediated cytotoxicity assay (4-h 51Cr release assay). The effector cells in spleen cells were T-cells which manifested asialo GM1 on their cell surfaces and were radiosensitive (1000 rads). The analysis of T-cell subsets using Lyt markers showed that the effector cells expressed the Lyt-2 antigen with a small amount of the Lyt-1 antigen on their cell surfaces. In addition antitumor activity of spleen cells of the tumor-bearing mice was weak in the early stage of tumor growth, strong in the mid-stage, and disappeared in the late stage. The mechanisms of antitumor activity of spleen cells of the tumor-bearing mice are discussed.

Animals↗
PubMed1982

The mechanism of cholera toxin-induced suppression of natural killer cytotoxicity.

In a previous publication, it was reported that the pretreatment of mouse spleen cells with cholera toxin (CT) greatly inhibited their natural killer (NK) cytotoxicity. In the present study, it was found that ganglioside GM1 blocked the inhibitory effect of CT, and mature T cells and nylon-wool-adherent cells were not involved in the CT-mediated inhibition of NK cytotoxicity. It was also demonstrated that subunit A or B dissociated from CT lacked the capacity to inhibit NK cytotoxicity. In addition, CT-mediated inhibition was persistent and irreversible. The implications of CT-mediated inhibition of NK cytotoxicity are discussed.

Animals↗
PubMed1981

Inhibition of mouse natural killer activity by cholera toxin.

The treatment of mouse spleen cells with cholera toxin (CT) extracted from Vibrio cholerae greatly reduced natural killer (NK) activity. The inhibition of NK activity was rapidly induced by CT treatment and persisted in the absence of CT. Even a very small amount of CT, such as 0.1 ng/ml, was effective in inhibiting NK activity. The inhibitory effect of CT on NK activity was lost upon preabsorption of CT with brain tissues, but not upon preabsorption with liver or kidney tissues.

Animals↗