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N Toyama

Publications and source records attributed to N Toyama.

49 records · Page 3Linked to original sources
PubMed1991

Signal transduction through the human IL-2 receptor beta-chain expressed in IL-6-dependent mouse B cell hybridoma.

Non-covalent association between at least two polypeptides, alpha (p55) and beta (p70), yields a high-affinity interleukin 2 receptor (IL-2R). Recent findings suggest that the beta-chain can mediate IL-2 signals on its own, while the alpha-chain is not involved in IL-2 signal transduction. To study the role of the beta-chain, directly, we transfected with the human IL-2R beta-chain cDNA a murine IL-6-dependent B cell hybridoma, F12-28, which originally did not express IL-2R. We established a stable transformant, beta E12, expressing the beta-chain (Kd = 1300 pM, 3000 sites/cell) in the absence of any detectable alpha-chain. We showed that (i) beta E12 manifested the intermediate affinity IL-2 binding, which was completely blocked with anti-human beta-chain antibody (Mik-beta 1); (ii) beta E12 acquired an ability to proliferate in response to IL-2 (greater than 0.1 nM) in a dose-dependent manner. These results clearly demonstrate that the beta-chain itself is directly involved in IL-2 signal transduction in the absence of the alpha-chain. Our results also suggest that a certain IL-6-dependent B cell line possesses cellular components) capable of transducing IL-2 signals.

Animals↗
PubMed1991

Use of a triple protease-deficient mutant of Bacillus subtilis as a host for secretion of a B. subtilis cellulase and TEM beta-lactamase.

The mature portion of the TEM beta-lactamase (BLA) gene (bla) derived from pBR322 was fused with the promoter and signal region of Bacillus subtilis cellulase (BSC) gene (bsc), and the productivity was compared with that of the cloned native bsc gene, using a wild-type B. subtilis strain and a strain deficient in three proteases (i.e., extracellular serine protease, extracellular neutral protease, and the major intracellular serine protease) as hosts. The effects of the sen, sacQ, and prtR genes, carried on the same plasmids, were tested as for the productivities of BSC and BLA. The production of BSC was increased 9-fold by using the combination of the triple-protease deficient strain and the sacQ gene, compared with that by using the wild-type strain as a host, and no degradation of BSC was observed in the triple-protease deficient strain. On the other hand, though the production of the BSC-BLA fusion protein increased 2.5-fold in the triple-protease deficient strain, the BLA activity was decreased after the cell reached the stationary phase of growth, possibly due to some proteolysis. These observations show different sensitivity of secretary proteins to cellular proteases, and suggest that BLA is decomposed by remaining minor proteases.

Amino Acid Sequence↗
PubMed1986

Evaluation of anticancer drugs by lymphocyte electrophoresis.

The spleen cells in tumor-bearing and normal mice treated with Krestin (PSK), mitomycin C (MMC) or adriamycin (ADM) were analyzed by cell electrophoresis and flow microcytometry. In normal mice, the splenocyte electrophoretic mobility histogram was observed as a bimodal pattern, and low and high mobility cells (LMC and HMC) corresponded with B and T cells, respectively. In sarcoma-180-bearing mice, an intermediate mobility peak (IMC) appeared between the low and high peaks. Although every anticancer drug depressed the IMC when the tumor was cured, MMC reduced the absolute number of splenic Ig+ and Thy-1+ cells, and ADM injured Ig+ cells in normal as well as in tumor-bearing mice. PSK, however, depressed splenomegaly by tumor-burden in spite of a slight increase in splenocytes of normal mice. In a previous paper, it was reported that the thymocyte mobility histogram was restored to a normal pattern by treatment with PSK in tumor-bearers, while it was made more abnormal by treatment with MMC because of injury to cortical thymocytes. From these results, it may be considered that an anticancer drug which restored the splenocyte mobility histogram to a normal pattern without damages to thymocytes is preferable for cancer therapy.

Animals↗
PubMed1985

[A pharmacokinetic study of cefoperazone during percutaneous transhepatic cholangial catheterization].

The metabolic fate of cefoperazone (CPZ) was studied in 19 cases which underwent percutaneous transhepatic cholangial catheterization (PTC-catheterization, PTCC) and were under various conditions of the liver function. The peak of bile levels of CPZ immediately after PTCC differed greatly from one case to another at 12.6-7,260 micrograms/ml with 1 g intravenous injection and 23.0-5,800 micrograms/ml with 2 g intravenous injection. The ratio of the peak of bile level to the serum level immediately after PTCC showed the highest negative correlation with the serum total bilirubin level. It also showed a significant negative correlation with GOT, GPT, Al-P and LAP. The serum CPZ level and half-life showed no significant trend except half-life showed a significant correlation with LAP. The recovery rate in urine up to 12 hours was in the range of 14.8-93.6%, showing a significant correlation with the ratio of the peak of bile levels to the serum level and the date of liver function tests. The bile level, serum level and recovery rate in urine at the time the bile outflow from the catheter has become constant after PTCC (during the course of PTCC) showed a trend almost similar to that immediately after PTCC, there being no significant difference as to each parameter during the course of PTCC and immediately after PTCC. In the cases in which the sample was collected by the cross-over technique, the ratio of the peak of bile levels to the serum level from immediately after PTCC to during the course of PTCC increased in 2 cases and decreased in 6 cases. The 2 cases that showed the increase in the ratio were the case in which the serum total bilirubin level improved almost to normal. Findings above suggest that sufficient biliary decompression can improve the movement of CPZ into bile, despite the fact that the pharmacokinetics of CPZ is affected by the liver function, particularly serum total bilirubin level, that a decrease in the movement to bile and a compensatory increase in urinary excretion are observed in jaundice and disturbance of the liver function and that the ratio of the peak of bile level to the serum level decreases during the course of PTCC rather than immediately after PTCC in some cases.

Adult↗
PubMed1975

Sugar production from agricultural woody wastes by saccharification with Trichoderma viride cellulase.

The saccharification of agricultural woody wastes was studied using a commercial enzyme preparation, Cellulase onozuka, derived from Trichoderma viride or the solid culture extracts of the fungus. With the intention of producing sugar at low cost, a simple procedure of enzymatic saccharification of rice straw, bagasse, and sawdust was studied. Delignifying methods of these wastes were investigated using dilute sodium hydroxide solution and dilute peracetic acid. Rice straw and bagasse were effectively delignified by boiling in a 1% sodium hydroxide solution for 3 hr or by autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr. The sawdust from a broad leaved tree (Machilus thunbergii) was delignified by autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr and by subsequent boiling in diluted 1/5 peracetic acid for 1 hr. This type of sawdust was also delignified by boiling in 1/5 peracetic acid for 1 hr and by subsequent autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr. The sawdust from a coniferous tree (Cryptomeria japonica) was delignified by boiling in 1/5 peracetic acid for 1 hr and by subsequent autoclaving at 120 degrees C in a 1% sodium hydroxide solution for 1 hr; however, the successive treatment by autoclaving with alkali solution and subsequent boiling with diluted peracetic acid failed to bring about the desired effect. The saccharification of delignified rice straw, bagasse, and sawdust was examined using Cellulase onozuka, wheat bran or rice straw solid culture at various substrate concentrations, resulting in the formation of 5 to 10% sugar solutions after incubation at pH 5.0, 45 degrees C for 48 hr. The optimum substrate concentration existed at around 10%. Reuse of cellulase solution and resaccharification of residual sawdust were considered to be inadequate.

Candida↗
PubMedDate not supplied

Segmental small bowel transplantation in the rat: comparison of lipid absorption between jejunal and ileal grafts.

BACKGROUND: From the immunological point of view, it is very important to evaluate the efficacy of segmental small bowel transplantation and to determine which part of the intestine, jejunum, or ileum should be used. In the present study, we investigated the absorptive function of the transplanted jejunum and ileum in the rat. METHODS: Syngeneic segmental small bowel transplantation (jejunal or ileal grafting) was performed. After surgery, body weight and fecal fat excretions were measured. In addition, bile acid concentration in bile juice was measured, and the response of both serum lipase and bile flow rate after oleic acid stimulation was evaluated. Recanalization of the lymphatic vessels was investigated by lymphangiography. RESULTS: There was no significant difference in body weight change between normal controls, jejunum-transplanted rats, and ileum-transplanted rats. In short gut rats, however, body weight was significantly impaired. Fecal fat excretion in short gut rats was the highest in the four groups, and it was significantly lower in ileal grafts than in jejunal grafts. Ileum-transplanted rats also showed a significantly higher bile acid concentration in bile juice than jejunum-transplanted rats. After oleic acid stimulation, serum lipase responded better in ileal transplants than in jejunal transplants, but the bile flow rate did not show significant change in either group. Recanalization of the lymphatic vessels was established on the 28th postoperative day. CONCLUSIONS: These results clearly show that ileal transplantation is more conducive to lipid absorption than jejunal transplantation.

Animals↗