Structural studies on minor components of trienomycin group antibiotics trienomycins D and E.
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Biomedical subjects
Publications and source records attributed to H Nomoto.
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Deuterium oxide (D2O), which is known to stimulate microtubule aggregation, enhanced the IgE-mediated 45Ca2+ influx, (14C)-arachidonic acid and histamine release in rat basophilic leukemia cells (RBL-2H3) in the same dose-dependent manner (up to 90% (v/v]. We compared the interaction between D2O and a variety of groups of pharmacological agents. A microtubule depolymerizing agent, demecolcine, which inhibited the IgE-mediated (14C)-arachidonic acid and histamine release without affecting 45Ca2+ influx, was counteracted by 45% D2O. Taxol, a microtubule stabilizing agent, which had an inhibitory effect on the above three steps, was also reversed by 45% D2O. These results would support the previous data on the interaction between D2O and microtubules and would further suggest that the status of microtubule aggregation may be related to the secretory process. Calmodulin inhibitors (W-7, trifluoperazine) blocked the IgE-mediated 45Ca2+ influx, (14C)-arachidonic acid and histamine release in the same dose-dependent manner, but were counteracted by 45% D2O. In contrast, the effects of proteinase inhibitors (TPCK, TLCK), an adenylate cyclase inhibitor (ddAdo), a phosphodiesterase inhibitor (aminophylline), a phospholipid methylation inhibitor (DZA + Hcy) and microfilament blockers (cytochalasin B and D) were not counteracted by 45% D2O. These results would suggest that D2O may be associated with calmodulin directly or indirectly possibly through some relationship between calmodulin and microtubules.
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Polyclonality of IgA production in IgA nephropathy (IgAN) was studied to elucidate the immunological aberrations in patients with this disease. The amounts of IgG, IgA and IgM and their kappa/lambda ratios in sera and supernatants of lymphocyte cultures were determined by the enzyme-linked immunosorbent assay. This method was sensitive enough to detect as little as 10% of monoclonal IgA in total IgA. The amount of IgA in IgAN was significantly increased in sera and supernatants without pokeweed-mitogen (PWM), but not changed in supernatants with PWM. There were no significant changes in the production of other immunoglobulins between IgAN and controls both in vivo and in vitro with and without addition of PWM. As far as the kappa/lambda ratios of immunoglobulins were concerned, no significant deviations were observed between IgAN and controls in any samples. These results indicated that increased IgA in patients with IgAN was polyclonal, supporting the concept of the heterogeneity of this disorder.
The three-dimensional structure of the mouse epidermal growth factor (EGF) in solution was studied by comparison of the 1H NMR spectra of alpha EGF (1-53) and beta EGF (2-53, des-asparaginyl 1 form). Using pH dependence of chemical shifts and a two-dimensional difference spectrum, the effect of the N-terminal deletion was investigated based on the complete assignment of the proton resonances. The affected residues were all found to be located exactly in the triple-stranded, beta-sheet core in the N-terminal domain of the EGF molecule.
Nine hundred and thirty-four cases of open renal biopsy using the 'Kawamura-modified forceps' have been performed over the past 9 years under general anesthesia. Sufficient amounts of renal tissue for routine histology, immunofluorescence staining and electron microscopy were obtained in all 934 cases. There were no serious major complications attributable to the procedure. It is concluded that this procedure can be performed easier and faster than the previous technique of percutaneous renal biopsy, although patients undergoing open renal biopsy with the Kawamura-modified forceps have to be transferred to the operating room for this procedure.
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The structure of carbohydrates in acetylcholine receptor (AChR) from Torpedo californica is reported. Oligosaccharides released quantitatively from the whole molecule by N-oligosaccharide glycopeptidase digestion were fractionated by thin-layer chromatography and further purified by high-performance liquid chromatography. We show that more than 70% of the total oligosaccharide chains in Torpedo AChR are of the high-mannose type with the structures (Man)8(GlcNAc)2 and (Man)9(GlcNAc)2. The structure of these oligosaccharides were determined by proton nuclear magnetic resonance spectroscopy. These two types of oligosaccharides were shown to be distributed different proportions in all subunits of Torpedo AChR. We also show that several kinds of complex-type oligosaccharides comprising the rest of the carbohydrate in the protein exist mainly in the gamma and delta subunits. The structure of the carbohydrate moiety that is distributed on the four subunits of AChR was also examined by susceptibility to endo-beta-N-acetylglucosaminidase and sialidase and by binding affinity to lectins, e.g. concanavalin A, leucoagglutinating phytohemagglutinin, and wheat germ agglutinin.
Staurosporine, microbial alkaloid which has been known to have antifungal activity was found to inhibit markedly phospholipid/Ca++dependent protein kinase (protein kinase C) from rat brain, with an IC50 value of 2.7 nM. However, it had little effect on the binding of 3H-phorbol-12, 13-dibutyrate (PDBu) to protein kinase C. The inhibition of protein kinase C was not competitive with phospholipid. This compound also showed the strong cytotoxic effect on the growth of HeLa S3 cells, with an IC50 value of 4 X 10(-12)M under the condition of 72 hr-exposure.
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This report described successful uses of continuous ambulatory peritoneal dialysis (CAPD) in the treatment of two patients with renal and cardiac failure. Case 1 was a 46-year-old woman with renal failure and mitral regurgitation. There were some predictable disadvantages to make a blood access and to increase the cardiovascular stress for her condition. Therefore, we treated her using CAPD and succeeded in improving her condition. Case 2. was a 62-year-old man with renal failure and aortic insufficiency. Beside having renal failure, he showed intractable cardiac failure. He was initially treated using in full ECUM (extracorporeal ultrafiltration method) and CAPD. Two week after admission he was successfully treated only by CAPD. It is suggested that CAPD will be the first choice of treatment in patients with renal and cardiac failure.
A nuclear antigen is recognized by autoantibodies in the sera of some patients with IgA nephropathy. Using these autoantibodies as a reagent, this antigen was purified 77.2-fold by ammonium sulfate fractionation, DEAE chromatography and Sepharose 6BCL gel filtration. The antigenicity of this antigen was sensitive to trypsin but resistant to RNase and DNase, suggesting that the antigenic determinant resided in protein and not nucleic acids. This antigen was inactivated at 56 degrees C for 3 h. Isoelectrophoretic focussing showed that the pI was below 4. The immunoblotting (Western transfer) assay showed a single polypeptide (69,000 Daltons) which proved to be a reactive antigen.
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A case of acute renal failure (ARF) associated with type A acute hepatitis followed by a dramatic response to plasmapheresis is described. A female patient was transferred to our hospital with a diagnosis of ARF associated with acute hepatitis. Since radioimmunoassay for IgM antibody to hepatitis A virus showed a positive reaction, recent infection with hepatitis A virus was suspected. Hemodialysis immediately performed after admission was not effective. Plasmapheresis was started on the 5th hospital day and there was a dramatic improvement in ARF and hepatitis. It is concluded that plasmapheresis is effective in the treatment of ARF associated with liver disease if it is applied in the early stage.
The interactions of Sepharose 4B-immobilized concanavalin A (ConA) with 10 glycoasparagines derived from ovalbumin were investigated quantitatively by frontal affinity chromatography. In this method, a carbohydrate solution is applied continuously to a ConA-Sepharose column and the retardation of the elution front is measured as a parameter of the strength of the interaction. The dissociation constant (Kd) for each saccharide with ConA can be determined. An analysis of the binding of p-nitrophenyl-alpha,D-mannoside has shown that the binding properties of ConA do not change essentially after immobilization on Sepharose 4B. Each of the ovalbumin glycoasparagines was labeled with tritium by the reductive methylation method for analysis. A comparison of the Kd values obtained showed that the binding of ConA varies considerably with very slight structural differences of the glycosyl chain. The results suggest that ConA recognizes a specific glycosyl chain structure, Man alpha 1-6(Man alpha 1-3)Man, in which at least one hydroxyl group at the C-3 position of C-6-linked mannose should be free. The glycoasparagines containing this structure bound strongly to ConA-Sepharose with dissociation constants below 3.4 X 10(-7) M.
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Non-oliguric acute renal failure is an increasing disease entity although management of this disease is yet to be established. Poisoning with the sublethal doses of HgCl2 provides an experimental model for the study of non-oliguric acute renal failure. The purpose of this study was to determine the mechanisms of regeneration of renal cortex in HgCl2 treated mice using whole body autoradiograms to evaluate the changes of DNA synthesis in the renal cortex as well as whole body organs in the mice. The whole body autoradiograms showed considerable uptake of thymidine in the renal cortex of the mice after 1.5 h, the highest uptake after 48 h and negligible uptake 8 days after the injection of HgCl2. On the other hand, autoradiograms showed no remarkable changes in the uptake of thymidine in the brain, lungs, heart and liver in HgCl2 treated mice. It was suggested that the initial treatment of non-oliguric acute renal failure within one week may play an important role in its prognosis.