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Biomedical subjects

M Beppu

Publications and source records attributed to M Beppu.

At least 19 recordsLinked to original sources
PubMed1992

Antigenic determinants of senescent antigen of human erythrocytes are located in sialylated carbohydrate chains of Band 3 glycoprotein.

Naturally occurring IgG autoantibody against Band 3 glycoprotein of human erythrocyte membrane (anti-Band 3) recognizes the erythrocytes modified with oxidizing or SH-blocking agents as well as senescent erythrocytes. Location of the antigenic determinants of Band 3 this autoantibody recognizes was investigated by competitive inhibition studies of the antibody binding to the modified cells. Autologous IgG binds to the modified erythrocytes, and purified Band 3 totally inhibits the binding. This inhibitory activity of Band 3 was not affected by digestion of Band 3 with various proteases. Treatment of Band 3 with endo-beta-galactosidase that destroys the poly-N-acetyllactosaminyl sugar chain of Band 3 or with neuraminidase resulted in loss of the inhibitory activity. Oligosaccharides released from Band 3 by hydrazinolysis effectively inhibited the binding of autologous IgG and 125I-labeled purified anti-Band 3 to the modified cells, whereas the oligosaccharides depleted of acidic components did not. Endo-beta-galactosidase and neuraminidase destroyed the activity of the oligosaccharides, but alpha-L-fucosidase did not. Furthermore, human lactoferrin that contains sialylated two N-acetyllactosaminyl units also exhibited potent inhibitory activity, and the activity was destroyed by endo-beta-galactosidase and neuraminidase. These results indicate that the antigenic determinants of Band 3 are located in sialylated poly-N-acetyllactosaminyl sugar chains. Based on this finding, mechanism of appearance of the antigen on senescent erythrocytes recognized by anti-Band 3 (senescent antigen) was discussed.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1992

The osteocutaneous fibula flap: an anatomic study.

Recent studies related to the fibula flap have disagreed regarding the anatomy of the cutaneous branches of the peroneal artery. To clarify this issue, various dissections of 35 injected fresh cadaver legs were done. Identifiable skin branches were found in 23 of 25 dissections. Skin branches from the proximal third of the peroneal artery always travelled an intramuscular course. Skin branches from the distal two-thirds of the peroneal artery were usually affixed to the posterior crural septum. Legs with peroneal artery skin branches had from three to seven branches (average: 4.7); each branch contributed to the fibular periosteal blood supply. The most reliably found skin branch was located within 2 cm of the fibula midpoint. These findings reinforce the fact that a large skin island supplied by branches of the peroneal artery can be harvested with the fibula flap, and that the most reliable cutaneous vessels are found in the lower two-thirds of the leg, run posterior to the fibula in the posterior crural septum, and are always associated with muscular side branches.

Fibula↗
PubMed1992

Generation of senescent antigen on erythrocytes by partial blocking of SH groups of the membrane proteins.

Human erythrocytes treated with diamide (0.2 mM) or N-ethylmaleimide (0.1 mM) at 37 degrees C for 1 h were susceptible to binding of anti-band 3 immunoglobulin G autoantibody and hemoglobin. A definite degree of cell modification appeared to be required for the effective bindings since the cells treated with the reagents above these concentrations were less susceptible. The enhanced binding activities of the cells treated with diamide were abolished on treatment with dithiothreitol. Partial blocking of SH groups of the membrane proteins but not disulfide-mediated protein cross-linking may be essential for the formation of band 3 senescent antigen, which may not be a neo-antigen formed by chemical modification of band 3 but an antigen formed by topological alterations of the molecules in the membrane.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1991

Augmentation of macrophage recognition of oxidatively damaged erythrocytes by substratum-bound fibronectin and macrophage surface fibronectin.

Thioglycollate-induced mouse peritoneal macrophages plated on a coverglass bind oxidized mouse erythrocytes in the absence of serum. Macrophages plated on a coverglass pre-coated with fibronectin (FN) were more active in binding of the oxidized erythrocytes. This effect of FN-coated coverglass was due to specific binding of an RGD-containing sequence of FN to FN-receptors on the macrophage, since GRGDSP hexapeptide in solution inhibited this effect, and GRGDSP-coated coverglass exhibited the same effect as FN-coated coverglass. Removal of FN originally present on the macrophage surface by trypsinization, prior to attachment to the coverglass, resulted in diminution of their ability of recognition of the oxidized erythrocytes, but the diminished ability was restored when the trypsinized macrophages were plated on a FN-coated coverglass, indicating that the cell surface FN is required for the macrophage recognition. Attachment to the coverglass was necessary for the cell surface FN to be effective. These results suggest that solid-phase FN, produced either by deposition of soluble FN to substratum or attachment of macrophage surface FN to substratum, activates the macrophages and augments their ability to recognize the oxidized erythrocytes.

Amino Acid Sequence↗
PubMed1991

Development of fluorescence and cross-links in eye lens crystallin by interaction with lipid peroxy radicals.

Senile nuclear cataract formation is associated with the accumulation of fluorescent insoluble proteins. alpha-Crystallin from bovine eye lens was treated with the lipid peroxy radicals generated by interaction of linoleic acid 13-monohydroperoxide or phosphatidylcholine hydroperoxide with methemoglobin. A blue non-tryptophan fluorescence composed of at least two kinds of fluorophores, stable and unstable on borohydride treatment, was produced. One of the stable fluorophores was identified as dityrosine by comparison of its retention times in amino acid analysis and HPLC with those of authentic dityrosine. Dityrosine was formed by the radical reaction, and less than 0.3% of the total tyrosine residues of the protein were transformed into dityrosine. The unstable fluorophores may be produced on the amino groups of alpha-crystallin by the non-radical reaction of the decomposition products of the radicals including monofunctional aldehyde species. Extensive intermolecular cross-links could not be explained only by the dityrosine content, but by the other modifications. Formation of fluorescence and intermolecular cross-links in alpha-crystalline in reaction with the lipid peroxy radicals suggested the participation of lipid peroxidation in the cataractous process.

Animals↗
PubMed1991

[The prognosis of segmental type of primary sclerosing cholangitis--a prognostic study of the cases].

Our review of the cases of segmental primary sclerosing cholangitis (PSC) in Japanese literature has found nineteen cases, of which our own case in 1976 has been in good health for fifteen years and three months after resection. The prognostic study was possible in sixteen cases. In twelve cases the lesions were resected. Ten of twelve are found in good health, the average length of survival being nine years and one month. There are two cases of death and the causes are unknown. The unresected cases (4 out of 16) are all dead. It is concluded that the prognosis of segmental PSC is good if the lesion is resected.

Adult↗
PubMed1990

Modification of glycophorin A during oxidation of erythrocyte membrane.

Human erythrocyte ghosts were oxidized with tert-butyl hydroperoxide and subsequently treated with tritiated borohydride to label the membrane proteins modified during the membrane oxidation. From the ghosts, oxidized-and-tritiated glycophorin A was isolated and characterized. No intermolecular cross-links were observed as analyzed by sodium dodecylsulfate gel electrophoresis. But, the number of lysine residues was significantly reduced and susceptibility to proteinases such as trypsin, chymotrypsin and pronase was lower than that of control glycophorin A. Trypsinization of the oxidized-and-tritiated glycophorin A gave insoluble and soluble trypsin fragments. After dansylation, N-terminal amino acids of the trypsin-fragments were determined. Dansyl amino acids from the insoluble trypsin fragments were not identical with those from control insoluble counterparts in the membrane-spanning region of glycophorin A molecule. Fractionation by gel filtration of dansyl-soluble trypsin fragments, and the N-terminal amino acid analysis of the fractionated peptides indicated that the peptides derived from the glycosylated region located in the outside of the membrane matrix were identical with those from control soluble counterparts. The results suggest that the glycosylated outside region of glycophorin A was modified only slightly but the hydrophobic membrane-spanning region was extensively modified during membrane oxidation, most likely by oxidized lipids.

Amino Acids↗
PubMed1990

Binding of anti-band 3 autoantibody to oxidatively damaged erythrocytes. Formation of senescent antigen on erythrocyte surface by an oxidative mechanism.

Incubation of human erythrocytes oxidized by iron catalysts, ADP/Fe3+ or xanthine/xanthine oxidase/Fe3+, with autologous IgG resulted in IgG binding as detected by enzyme immunoassay using protein A-beta-galactosidase conjugate. The binding of autologous IgG to ADP/Fe3(+)-treated erythrocytes maximized when the cells were treated with 1.8:0.1 mM ADP/Fe3+, and declined when treated above this concentration, suggesting that autologous IgG binds to moderately but not to excessively oxidized erythrocytes. The antibody involved in the binding was anti-Band 3, the autoantibody known to bind to aged erythrocytes, because isolated anti-Band 3 bound to the oxidized cells, but anti-Band 3-depleted autologous IgG did not. In addition, purified Band 3 inhibited the autologous IgG binding. Anti-alpha-galactosyl IgG, another natural antibody which has been reported to bind to aged erythrocytes, did not bind to the oxidized cells. Oxidation of membrane lipids, SH-groups of membrane proteins, and Hb of these cells was slight, but the cells contained an increased amount of membrane-bound native Hb, indicating that the oxidized cell membrane has an altered property. alpha-Tocopherol prevented the lipid oxidation and the subsequent IgG binding. Reduction of the oxidized erythrocytes with dithiothreitol resulted in a loss of the IgG binding. These results suggest that anti-Band 3 binding sites (Band 3 senescent antigen) are formed on moderately oxidized erythrocytes as a result of oxidation of membrane protein SH-groups which can be mediated by the membrane lipid oxidation and that formation of the anti-Band 3 binding sites on the oxidized cells is an essentially reversible membrane event which is linked to oxidation and restoration of the protein SH-groups.

Adenosine Diphosphate↗
PubMed1990

Hepatic subsegmentectomy with segmental hepatic vein sacrifice.

There is no clinical disorder in partial Budd-Chiari syndrome or in a major hepatic vein ligation in hepatic trauma. When considering these findings, it is significant to investigate hepatic subsegmentectomies in which a major hepatic vein is sacrificed. We performed such hepatic subsegmentectomies in nine cases of hepatocellular carcinoma. With the sacrifice of the right hepatic vein, S7, S8 resection was done in three patients, S7 resection in two patients, S8 resection in one patient, and S5 resection in one patient. With the sacrifice of the middle hepatic vein, S8 resection was done in two patients. These resections were successfully performed with no postoperative problem. Further, there were no significant differences in postoperative liver function tests of the patients from those of a control group of the commonly performed systematic segmentectomy and subsegmentectomy. By performing such resections, resection was made possible in three cases and curative resection was made feasible in six cases.

Aged↗
PubMed1990

Metabolism in vivo of 3,4,5,3',4'-pentachlorobiphenyl and toxicological assessment of the metabolite in rats.

Metabolism in vivo of 3,4,5,3',4'-pentachlorobiphenyl (PenCB) and toxicological assessment of the metabolite were investigated using male Wistar rats. Only one metabolite was isolated from the feces of rats administered 3,4,5,3',4'-PenCB. By gas chromatography-mass spectrometry, the methylated metabolite was identified with the synthesized authentic sample, 4'-methoxy-3,4,5,3',5'-PenCB. This indicated that the metabolite was 4'-hydroxy-3,4,5,3',5'-PenCB, which was produced via a 4',5'-epoxide formation and subsequent NIH-shift of the 4'-chlorine to the 5'-position. Administration of the metabolite at either single i.p. dose of 3 or 10 mg/kg to rats did not cause any toxic and biological effects such as body weight loss, atrophy of thymus and spleen, liver hypertrophy, increase of liver lipids, or 3-methylcholanthrene-type induction of liver enzymes. These changes were observed in rats administered with 3,4,5,3',4'-PenCB at a single dose of 3 mg/kg. In addition, a trace amount of 4'-hydroxy-3,4,5,3',5'-PenCB could be detected in rat liver 5 d after treatment with 3,4,5,3',4'-PenCB or 4'-hydroxy-3,4,5,3',5'-PenCB. The amount of this metabolite excreted in feces during 5 d after treatment with 3,4,5,3',4'-PenCB accounted for only 1.3% of dose. In 4'-hydroxy-3,4,5,3',5'-PenCB-treated rats, about 60% of dose was excreted as unchanged in feces for 5 d. These results suggest that this metabolite is a detoxified product and has no longer the high affinity for the liver, being excreted rapidly into the feces.

Animals↗
PubMed1979

Preparation of concanavalin A-ricin A-chain conjugate and its biologic activity against various cultured cells.

For the development of therapeutic agents that possess tissue-specific carriers, a method was devised to synthesize an artificial protein hybrid conjugate containing a moiety which binds to a cell membrane receptor and an active fragment of a toxic protein. By the introduction of an activated sulfhydryl group into concanavalin A (Con A), a conjugate of Con A and the ricin A-chain cross-linked with a disulfide linkage was synthesized. The purified conjugate was studied with regard to its inhibitory activity against protein synthesis in cell-free and cultured cell systems. The Con A-rich A-chain conjugate retained about one-third the inhibitory activity of ricin in a cell-free protein synthesis system. It also was highly toxic to cultured normal cells. These results indicate that the conjugate is a structural and functional analog of ricin and that the original membrane-binding chain (B-chain of ricin) could be replaced by Con A. Transformed cells were insensitive to this conjugate and required a longer preincubation time. The sensitivity of the normal cells was reduced in the presence of local anesthetics.

Animals↗
PubMed1979

Covalently cross-linked monovalent, divalent, and tetravalent derivatives of concanavalin A.

Dimeric succinyl-concanavalin A was cross-linked with ethylenediamine using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide a condensing agent. Thus, a divalent dimer and a tetravalent tetramer composed mostly of covalently cross-linked subunits bearing altered net charges were obtained. Photoaffinity labeling of the cross-linked dimer with p-azidophenyl alpha-D-mannopyranoside resulted in a specific label for its saccharide-binding site and yielded a nonvalent dimer and a monovalent dimer (showing no subunit exchange). However, hemagglutination and glycogen precipitation data suggested that the labeled binding site is shielded but not destroyed by the label and can still bind weakly an external saccharide ligand possibly due to unsteadiness of the shielding label. Although nonvalent and monovalent derivatives were mitogenic as well as divalent and tetravalent derivatives for mouse splenic lymphocytes, binding and stimulation experiments indicated that their stimulating efficiencies after binding to the cells were far lower than those of the multivalent counterparts. Their activities were inhibited by methyl alpha-D-mannopyranoside, suggesting that the weak activities of nonvalent and monovalent derivatives were due to the labeled sites entirely and partly, respectively. We suggest that the triggering of lymphocyte mitogenesis by concanavalin A may depend on cross-linkage of cell surface receptors.

Animals↗
PubMed1979

[An experimental study on the effects of the plating method for bone fractures--with reference to bone union and bone strength (author's transl)].

The plating method for bone fractures is in wide use. The author studied both new bone formation and bone atrophy of the cortex of fracture site after long periods of plating. This study is concerned with the bone strength of the fracture site as influenced by rigid plate fixation, and also with bone union after the removal of the plate. The experimental results, using mature rabbits as subjects, showed the following: X-rays of the bone union at the fracture site treated by the plating method confirmed evident union at 8 weeks after surgery. The bone strength at the region of this union, as tested by the bending method (an Instron Type Testing Machine was used), showed its highest values at 28 weeks after surgery. Yet, this was only 60% of the bone strength as measured at a non-fracture site; it then gradually declined in strength. On the other hand, in the case where the plate had been removed 8 weeks after surgery, bone strength was recovered to the same level as that of non-fracture sites 16 weeks after surgery. In conclusion, rigid plate fixation for a long period may result not only in progressive bone atrophy of the cortex but also in a delayed remodeling of the bone at the region of the bone union. It is, therefore, very important to remove the plate as early as possible once union has been achieved. Careful observation, however, is necessary during the short time between plate removal and the period when bone strength becomes again normal.

Animals↗