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Biomedical subjects

S Shirahama

Publications and source records attributed to S Shirahama.

At least 55 records · Page 3Linked to original sources
PubMed1987

Effects of lysine and glutamic acid or [corrected] Mg++ on the conformations of C3 and B, and the activation of the alternative complement pathway.

The conversion of C3 and B in the mixture of C3, B, D and Mg++ ions was inhibited in the presence of arginine and lysine, but not in the presence of glutamic acid and aspartic acid among other amino acids. Application of dialyzed plasma to a lysine-Sepharose column resulted in elution of B and a part of D in pass-through fractions, and C3 and the other part of D were retained in the column, subsequently eluted by increase in salt concentrations. C3, B and a part of D were eluted in pass-through fractions, and C3 and the other part of D were retained in the column, subsequently eluted by increase in salt concentrations. C3, B and a part of D were eluted in pass-through fractions when applied to glutamic acid-Sepharose. A highly purified D preparation appeared in the pass-through fraction of the lysine-Sepharose column, suggesting that D may form a complex in plasma. The intensity of intrinsic fluorescence of C3 decreased in the presence of arginine to the largest extent. Lysine affected the intensity less than arginine. Kd was calculated to be 0.42 mM for arginine and 0.55 mM for lysine in the interaction with C3. The intensity of intrinsic fluorescence of B decreased in the presence of aspartic acid and glutamic acid (Kd = 0.48 mM for aspartic acid and 0.24 mM for glutamic acid). Arginine or lysine affected the intensity of B less than those anionic amino acids. The presence of Mg++ ions resulted in a decrease in the fluorescence intensity of C3 and B.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1986

Inhibition by lysine and arginine of the conversion of C3 and B in the serum and a purified system.

When human serum was incubated at 45 degrees C for 30 min, C3 and B were converted to C3b and Bb. Molecular weights of purified C3 and B were shown not to change after incubation at 50 degrees C. Spectropolarimetry indicated that the secondary structures of C3 and B changed after incubation at higher temperature. The titration of SH groups in the C3 molecule showed the liberation of an SH group. These results show that the alternative complement pathway is activated at raised temperatures without known activators such as zymosan or lipopolysaccharide (LPS). This may be due to the accelerated interaction of conformationally changed components of the alternative pathway such as C3 and B. Using this system, effects of various substances on the interaction of C3 and B in serum and the purified system were investigated. The addition of arginine and lysine resulted in the inhibition of the conversion of C3 and B in the serum at elevated temperature. Other amino acids such as anionic amino-acids and NaCl did not influence the conversion. In the purified system, only arginine and lysine prevented the conversion of C3 and B, when C3, B and D were incubated in the presence of Mg++ and amino-acids. Since lysine and arginine did not inhibit the enzymatic activity of D, these data suggest that arginine and lysine prevent the interaction of C3 and B in the serum at elevated temperatures.

Animals↗
PubMed1985

Inhibition by various peptides of the activation of C1, the first component of complement, and the interaction of C gamma 2 domain of IgG with C1q.

Three groups of peptides were synthesized, each of which was proposed to be a part of the C1q binding sites of the C gamma 2 domain of IgG. They were: Trp(277)-Tyr-Val-Asp-Gly (WYVDG), Thr(289)-Lys-Pro-Arg (tuftsin) and Gly(316)-Lys-Glu-Tyr-Lys (GKEYK) or portions of these peptides. Assays included CH50, consumption of serum complement induced by heat-aggregated IgG, C1 hemolysis and an enzyme immunoassay that directly measures interaction between C1q and IgG. Peptides near Gly(316) such as GKEY, GKE or EYK inhibited CH50 and heat-aggregated IgG-induced consumption of serum complement. WYVDG also inhibited CH50, with 50% inhibition at 2.05 mM, which was more than the concentrations of peptides near Gly(316) at 50% inhibition. Tuftsin was only slightly inhibitory in both systems. Results of C1 hemolysis indicated that dipeptides composed of two aromatic amino acids, especially Trp-Tyr, were more inhibitory than dipeptides of which one residue was an aromatic amino acid. Peptides such as EYK, GKEY or GKE were very inhibitory, and tuftsin was far less inhibitory than these peptides in C1 hemolysis. Results of enzyme immunoassay also showed that dipeptides composed of two aromatic amino acids were more inhibitory than dipeptides of which one residue was aromatic amino acid. WYVDG was most inhibitory in enzyme immunoassay, but tuftsin, EYK, GKEY GKE and KE were less effective.

Binding Sites↗
PubMed1985

Conformational changes of complement components C3 and B induced at higher temperature.

When purified C3 or B of human complement was incubated at various temperatures for 30 min, B lost most of its antibody combining capability at 46 degrees C, and C3 lost it at higher than 50 degrees C. When C3, heated B, D and Mg++ ions were incubated, there was a precipitous decrease in C3 conversion in the presence of heated B between 44 and 46 degrees C. No C3 conversion was observed in the presence of B heated at 50 degrees C. When C3 heated higher than 50 degrees C was incubated with B, D and Mg++ ions, C3 conversion decreased dramatically, but B was converted almost normally, suggesting that B could be complexed with heated and conformationally altered C3 and cleaved by D. The fluorescence intensity of heated C3 excited at 288 nm gradually decreased between 44 and 46 degrees C. The fluorescence 288 nm gradually decreased between 44 and 46 degrees C. The fluorescence intensity of C3 was slightly increased by 1-anilino-8-naphthalene sulfonate (ANS) at 50 degrees C and significantly increased at 56 degrees C, while ANS enhancement of fluorescence of B began at 46 degrees C and was significant at 50 degrees C, indicating that the surface of B and C3 became hydrophobic between 44 and 46 degrees C, and 46 and 50 degrees C, respectively. These results suggest that conformations of C3 and B have low melting points at which they change confirmations drastically.

Anilino Naphthalenesulfonates↗
PubMed1985

Enzyme immunoassay of C1q and its application to the detection of C1q antigens in urine.

A highly sensitive enzyme immunoassay for the determination of C1q, a subcomponent of the first component of complement, C1, was developed to determine C1q in body fluid. Anti-C1q F(ab')2 fragments were immobilized on silicone rubber and after the interaction of anti-C1q with C1q, Fab' fragments of anti-C1q coupled with beta-D-galactosidase were added. The amounts of C1q were measured by enzymatic activity of beta-D-galactosidase to cleave 4-methylumbelliferyl-D-galactoside. A calibration curve of C1q indicates that C1q could be determined in the range of 0.3 ng/ml-1 mg/ml, the optimal range being 1-100 ng/ml. While C1q was not detectable in the urine of healthy volunteers, C1q could be determined in the urine of patients with renal diseases. The highest level of C1q detected was 31.8 ng/ml in urine of chronic nephritis.

Complement Activating Enzymes↗
PubMed1984

Inhibition of the activation of the first component of complement, C1, by various amino acids or peptides.

The effects of various amino acids (or their analogues) and peptides on the activation or consumption of human complement by erythrocytes bound with hemolysin or heat-aggregated immunoglobulin G (aggIgG) were studied by using the hemolysis of hemolysin-bound erythrocytes, the consumption of complement by aggIgG in the serum, the hydrolysis of acetyl tyrosine ethyl ester by activated Cl (Cls), Cl hemolysis and a newly developed enzyme immunoassay, which directly measures interaction between Clq and aggIgG. Amino acids or peptides which were proposed to comprise Clq binding sites of the C2 region of IgG or their analogues were used. CH50 was inhibited by lysine or arginine to the largest extent, but other amino acids, including tranexamic acid and epsilon-amino caproic acid were not inhibitory up to 60 mM. The consumption of serum complement by aggIgG was prevented by arginine or lysine (about 60% inhibition at 60 mM) and by histidine to a lesser extent. The activation of Cls in the Cl complex by aggIgG precipitated at pH 5.5 was most inhibited by lysine, and to a lesser extent by tranexamic acid, arginine and epsilon-aminocaproic acid, but not glutamic acid or glycine. The results of Cl hemolysis indicated that, of all amino acids soluble at neutral pH, lysine and arginine were most effective in the inhibition of Cl hemolysis. Tranexamic acid and epsilon-aminocaproic acid were less effective, and glycine and norleucine were hardly effective. Among the dipeptides used, those that are composed of aromatic amino acids were very effective in the inhibition of Cl hemolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1984

Pustulosis vegetans.

Sterile pustules and crusted vegetative plaques on the trunk and limbs developed in a 24-year-old man. They left cribriform scars after healing. Histologically, the lesions showed epidermal proliferation and pustulosis resembling that found in "pyoderma vegetans" and pemphigus vegetans. The lesions were effectively suppressed in two months by the topical application of methoxsalen followed by UV-A irradiation. Studies revealed that the chemotactic activity of polymorphonuclear leukocytes (PMNs) in the patient's peripheral blood was enhanced and that an extract of lesional crusty scales showed the presence of a PMN chemotactic factor. This factor had a molecular weight near 12,500 daltons similar to that reported in psoriasis scales. We speculate that tissue destruction due to complement activation, possibly induced by immune complex-mediated reactions in the dermis, provoked a process of transepithelial elimination of the inflammatory products.

Adult↗
PubMed1980

Human IgM anti-IgM cytotoxin for B lymphocytes.

B lymphocytes were shown previously to be killed at 5 degrees C by some autologous and allogeneic human sera. We show here that such cold cytotoxins are directed against immunoglobulins on the surface of B lymphocytes. The activity is partially removed by passing serum through IgG-coupled Sepharose and usually completely removed by passing serum through IgM-coupled Sepharose. Activity is regained from the columns by acid elution and IgM inhibits the cytotoxicity of these eluates. 125I-labeled eluates bind to IgG- and IgM-coupled Sepharose beads and binding is inhibited by IgM and to a lesser degree by IgG thus showing a primarily more avid binding to IgM as compared to IgG. Furthermore, the 125I-labeled cytotoxic eluates recognize the same determinant(s) on IgM and IgG. We suggest tht IgM anti-IgM antiimmunoglobulin may regulate immune reactivity by binding to B-lymphocyte surfaces.

Absorption↗
PubMed1980

Preliminary evidence of dual-marked lymphocytes in thoracic duct lymph fluid.

Thoracic duct lymphocytes from patients receiving thoracic duct drainage as a pretransplant therapy were examined for cell surface markers. Patients followed over the drainage time period showed a variable but decreasing percentage of E-rosette-positive cells in the lymph fluid. A substantial percentage of these E-rosette-positive cells also had C3 receptors on their cell surface. Reactions of the whole lymphocytes with a heteroantisera to human B-lymphocyte antigens reflected the increasing proportion of B cells in the samples, but also indicated that a fraction of the T cells have Ia-like antigens on their surface marker characteristics. Significance of these cells with respect to graft survival is discussed.

Animals↗
PubMed1979

IgM anti-IgM cold lymphocytotoxins to B cells.

Cytotoxic antibodies to B lymphocytes have been shown to be IgM. They are not absorbed by red blood cells and therefore not absorbed by red blood cells and therefore not directed against the I antigen of red cells. They are also not inhibited by mannose, as are certain natural cytotoxins against lymphocytes. Methods for producing purified eluates of IgM anti-IgM antibodies are given. These antibodies are postulated to be immunoregulative by acting on B lymphocytes.

Absorption↗
PubMed1979

A simple, rapid micro-latex fixation test.

A micro-latex fixation test (LFT) for the determination of rheumatoid factor (RF) is presented. Its advantages compared to similar tests are greater precision, simplicity, increased sensitivity, lower cost, reproducibility and adaptibility to large-scale testing. Micro-LFT titres are presented from a wide range of sample populations. The majority of normal samples show measureable titres whereas rheumatoid patients show high titres. A large sampling of pre- and post-transplant sera from kidney patients was studied and the micro-LFT titres were in the range of normal persons. The transplant sera were tested for lymphocytotoxic antibodies and no correlation was observed with the micro-LFT titres.

Adult↗