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Y Takada

Publications and source records attributed to Y Takada.

At least 631 records · Page 35Linked to original sources
PubMed1985

The activation of Glu- and Lys-plasminogens by streptokinase: effects of fibrin, fibrinogen and their degradation products.

Studies were performed on the activation of a native form of human plasminogen (Glu-plg) or its degraded form (Lys-plg) by streptokinase (SK) in the presence of fibrin, fibrinogen, SK-potentiator, fragment D or E. When Glu-plg (0.1 microM) was activated by 0.5 u/ml of SK in the presence of 100 micrograms of S-2251 and 0.1 microM of fibrin, fibrinogen or their degradation products (potentiating agents), fibrin enhanced the rate of the hydrolysis of S-2251 to the largest extent. Fragments D and E only slightly enhanced it. The order of effectiveness of enhancement was fibrin greater than SK-potentiator greater than fibrinogen greater than D greater than E. When Lys-plg (0.1 microM) was activated by 0.5 u/ml of SK in the presence of potentiating agents, SK-potentiator enhanced the hydrolysis of S-2251 to the largest extent. The enhancement was far less in comparison to the enhancement of the hydrolysis by Glu-plg and SK. The measurement of delta OD405/min at the time of 50% hydrolysis of the substrate was performed in order to compare the effects of concentrations of potentiating agents. The maximum enhancement was obtained at almost an equimolar ratio of plasminogen and fibrin. Fifty percent enhancement was obtained at 0.05 microM for SK-potentiator, 0.072 microM for fibrinogen, 0.21 microM for D and 0.35 microM for E. Fibrin caused the largest extent of enhancement among other potentiating agents. These results may indicate that a trimolecular complex between SK, plasminogen and potentiating agents hydrolyzes S-2251 more effectively than SK-plasminogen complex, thus a trimolecular complex being a better activator than SK-plasminogen complex. Although D and E enhanced only slightly the rate of hydrolysis of S-2251 at equimolar ratio to plasminogen, increase in their concentration resulted in the same extent of enhancement as shown in the presence of fibrinogen or SK-potentiator.

Fibrin↗
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

Computer-analyzed EEG before and after bypass surgery. Quantification by a computerized wave form recognition method.

Chronological changes of the EEG before and after extracranial-intracranial arterial bypass surgery were studied on 12 patients with minor completed stroke of the carotid circulation. Instead of a power spectrum used in the conventional computer analysis, a wave form recognition method, which well correlated with visual assessment of the EEG, was applied to the present computer analysis of the EEG. The EEG changed mainly in the parietal, occipital, anterior and middle temporal records of the affected cerebral hemisphere. Deterioration of the EEG continued until 1 month, and improved gradually during 3 and 6 months after the operation. However, it was difficult to conclude that the EEG improved by surgery.

Adult↗
PubMed1985

The association of imperforate anus and Hirschsprung's disease in siblings.

The recognition of Hirschsprung's disease is often delayed in children with imperforate anus. Two siblings with imperforate anus who were born of consanguineous parents had persistent constipation after the repair of the anorectal malformation. Subsequently colon biopsy confirmed that each had long segment aganglionosis beginning at the splenic flexure. A suspicion that these two disorders may coexist is mandatory for early correct diagnosis.

Anus, Imperforate↗
PubMed1985

Activation of human and rabbit prokallikrein by serine and metalloproteases.

Human and rabbit kidney and urine contain an inactive form of kallikrein. Studies on the mRNA sequence suggested that the active form of the enzyme and the propeptide are linked by a peptide bond between a basic and hydrophobic amino acid. We studied the activation of prokallikrein by serine proteases and a neutral metalloproteinase, thermolysin, because serine proteases cleave the peptide chain after a basic amino acid and thermolysin before a hydrophobic amino acid. The activity of kallikrein was measured by RIA and with a fluorogenic peptide substrate. Trypsin was used as a standard reference activator. We found that human plasmin and plasminogen, activated by urokinase, activate prokallikrein. Pronase coupled to Sepharose also enhanced the activity of the renal kallikrein zymogen. On a molar basis, thermolysin was a more effective activator of prokallikrein than trypsin. The activation by thermolysin was blocked by the inhibitor phosphoramidon, but not by DFP or SBTI. These experiments indicate that, in addition to serine proteases, neutral metalloproteases of tissues may activate prokallikrein.

Animals↗
PubMed1985

Reaction p

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Journal Article↗
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

Neurogenic hypertension in the Guillain-Barré syndrome.

We report a case of Guillain-Barré syndrome associated with hypertension. The hypertension was related to glossopharyngeal and vagal nerve impairment. Plasma noradrenaline concentration (NA) and plasma renin activity (PRA) were elevated. The possible mechanism of the neurogenic hypertension produced by the sino-aortic denervation is discussed.

Adolescent↗
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↗
PubMed1985

[Production and characterization of a monoclonal sperm immobilizing antibody to seminal plasma antigens].

Rat spleen cells immunized to human azoospermic semen were fused with mouse myeloma cells (P3 X 63Ag8Ul) to obtain hybridomas which produce monoclonal sperm immobilizing antibodies. Of 114 hybrid clones obtained, 10 were found to produce antibodies with sperm immobilizing activity with complement. One clone (1C4) producing the highest antibody titer was chosen for further characterization. Chromosome analysis showed that 1C4 hybridoma cells contained two types of chromosomes which were derived from rat and mouse. Rat Ig was detected in both the cytoplasma and the culture medium of the cells by direct immunofluorescent test and immunodiffusion test, respectively. Gammaglobulin fractions from the culture medium had a strong sperm immobilizing activity and showed a common single precipitin line against human seminal plasma and human milk proteins. It was proved that the monoclonal antibody was produced to No. 7 antigen and not to No. 3 antigen (lactoferrin) in human seminal plasma, both of which have a common antigenicity to human milk proteins and compose the sperm coating antigens.

Animals↗