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Biomedical subjects

Y Takada

Publications and source records attributed to Y Takada.

At least 577 records · Page 32Linked to original sources
PubMed1987

Kinetic analyses of the activation of Glu-plasminogen by urokinase in the presence of fibrin, fibrinogen or its degradation products.

The kinetics of the activation of Glu-plasminogen (Glu-plg) and Lys-plasminogen (Lys-plg) by urokinase (UK) were studied in purified systems. The activation of plasminogen by UK in the purified systems followed Michaelis-Menten kinetics with a Michaelis constant (Km) of 1.45 microM and a catalytic rate constant (kcat) of 0.93/sec for Glu-plg as compared to 0.25 microM (Km) and 0.82/sec (kcat) for Lys-plg. In the presence of fibrin and fibrinogen or its plasmin degradation products (fragment D and fragment E), Km for Glu-plg hardly changed, whereas kcat for Glu-plg increased. Effect on increase in kcat was in the order of fibrin greater than fibrinogen greater than D greater than E. Fibrin, fibrinogen, D and E did not influence the activation of Lys-plg by UK. These results indicate that Glu-plg bound to fibrin, fibrinogen, D or E becomes easily activatable by UK. The activation of Lys-plg, however, is not influenced in the presence of fibrin, fibrinogen, D or E.

Enzyme Activation↗
PubMed1987

Differences in the activation rates of plasminogen by tissue plasminogen activator and urokinase.

The activation of a native form of plasminogen (Glu-plg) by tissue plasminogen activator(t-PA) was enhanced when the plasma was clotted by the addition of thrombin or thrombin plus Ca++. Cross-linking of fibrin in the clotted plasma did not inhibit the fibrin-associated enhancement of the activation of plasminogen by t-PA. When fibrinolysis induced by t-PA in the clotted plasma was measured using enzyme immunoassay, lysis of non cross-linked fibrin in the clotted plasma was faster than lysis of cross-linked fibrin, however such decrease in the extent of fibrinolysis was observed in cross-linked fibrin even in the absence of alpha 2antiplasmin (alpha 2AP) in a purified system. When Glu- or Lys-plg (modified plg) was activated by t-PA, the presence of fibrin enhanced significantly the extent of activation of both Glu- and Lys-plg, but the activation of Glu-plg by urokinase (UK) was enhanced in the presence of fibrin. The activation of Lys-plg by UK was rather inhibited in the presence of fibrin.

Enzyme Activation↗
PubMed1987

Relationship between urinary fibrinogen degradation products and various types of chronic nephritis.

The concentration of urinary fibrin(ogen) degradation products (FDP) was determined by using enzyme immunoassay and radio immunoassay, and their urinary levels were compared with histologically classified types of glomerulonephritis. Urinary FDP levels were higher in the severe type of proliferative glomerulonephritis and at the active phase of systemic lupus erythematosus (SLE). They were also high in the membranous glomerulonephritis. Molecular weight of urinary FDP of a patient with severe proliferative glomerulonephritis was determined to be 150,000 and 68,000, respectively after gel filtration. Urinary FDP levels were higher in patients with glomerular fibrin deposit than in patients without fibrin deposit or normal volunteers. The amounts of excreted protein in urine was not related to the amounts of FDP. Decrease in the reciprocal of serum creatinine levels resulted in high urinary FDP levels, indicating that high urinary FDP levels may represent deterioration of renal function.

Chromatography, Gel↗
PubMed1987

The very late antigen family of heterodimers is part of a superfamily of molecules involved in adhesion and embryogenesis.

The very late antigen (VLA) protein family contains at least five related heterodimers, including a fibronectin receptor structure, and probably other cell substrate adhesion receptors. These cell-surface VLA proteins were immunopurified from human placenta (VLA-1, VLA-3, and VLA-5), platelets (VLA-2), and Molt-4 cells (VLA-4) using a series of monoclonal antibody-Sepharose immunoaffinity columns. After further purification by gel electrophoresis, the N-terminal amino acid sequence for each of the five VLA alpha subunits was determined. In the first 14 positions, the five VLA alpha subunits showed an average of 42% homology to each other, rising to 59% including conservative amino acid substitutions. In addition, the alpha subunits from the LFA-1, Mac-1 (CR-3), and p150,95 family of heterodimers, the vitronectin receptor-platelet GPIIb/IIIa family, and a position-specific (PS) antigen important in Drosophila embryogenesis each showed average homologies of 31-40% to individual VLA alpha sequences and 46-52% homology to VLA alpha subunits including conservative substitutions. Taken together, these results suggest that the VLA proteins, the LFA-1, Mac-1, and p150,95 family, the GPIIb/IIIa, vitronectin receptor family, and the Drosophila PS antigens have evolved as four subgroups in a highly conserved supergene family of receptors involved in fundamentally important functions, such as cell adhesion, migration, and embryogenesis.

Amino Acid Sequence↗
PubMed1987

Kinetic analyses of potentiation of plasminogen activation by streptokinase in the presence of fibrin or its degradation products.

When Glu-plasminogen (Glu-plg) was activated by various amounts of streptokinase (SK), Km of the hydrolysis of S-2251 by the mixture of Glu-plg and SK did not change, but Vmax increased with an increase in the amount of SK. Since low concentrations of SK-plg complex do not result in its conversion to the SK-plasmin complex by mutual activation, these results seem to suggest that the SK-plg complex may be a better activator when S-2251 is used as a substrate. When Glu-plg was activated by SK in the presence of fibrin(ogen) or its degradation products (potentiating agents), Km did not change with an increase in the concentration of each potentiating agent, but Vmax increased. The effects of potentiating agents on the kcat values of these activators were in the order of fibrin greater than fibrinogen greater than D greater than E.

Drug Synergism↗
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↗
PubMed1987

Activation of human prorenin by neutrophil elastase.

Although about 90% of human renin circulates as inactive prorenin, the mechanism of prorenin activation in vivo is not known. We found that human polymorphonuclear leukocytes (PMN) activate prorenin at a neutral pH. Prorenin was partially purified from human amniotic fluid, and its activation was measured by the release of angiotensin I from sheep angiotensinogen. In control experiments, thermolysin was the standard activator. PMN cells were separated from blood and, after N2 cavitation or degranulation by cytochalasin, were fractionated by differential centrifugation. Elastase and cathepsin G activities were determined with synthetic fluorescent substrates. The activators of prorenin concentrated in the azurophil granules were released by Triton; most of the activation was due to elastase. Elastase, purified from human PMN, activated prorenin completely. The activation by the granular fraction was inhibited 77% by a specific elastase inhibitor in the presence of a detergent, but only 22% by a cathepsin G inhibitor. After inhibition of elastase, the residual activity was inhibited by diisopropylfluorophosphate; thus, it was due to a serine protease(s) such as cathepsin G. We suggest that human renin fully activated by elastase may still contain an N-terminal pentapeptide fragment of the propeptide.

Amniotic Fluid↗
PubMed1987

Biochemistry of human converting enzyme.

Angiotensin converting enzyme (ACE, EC 3.4.15.1) was purified to homogeneity from human kidney and its specific antibody was raised in the rabbit. The antibody cross-reacted equally with human enzymes from kidney, lung, intestine, plasma and urine. Immunofluorescent and immunoelectron microscopic observation indicated that the enzyme was located on the plasma membrane and micropinocytic vesicles at the luminal site of vascular endothelium in the lung. It was also present on the brush border, intercellular and basal infolding membranes of proximal tubular epithelium, but was not detected on the distal tubular epithelium or vascular endothelium in the kidney. ACE was demonstrated immunocytologically in human alveolar macrophages and renal carcinoma tissues. The carcinoma tissue contained a possible isoenzyme of ACE differing in part immunologically from the enzyme of normal kidney.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1987

Angiotensin converting enzyme in sarcoidosis and in silicosis.

Angiotensin converting enzyme (ACE) activities of bronchoalveolar lavage fluid (BALF) and serum in patients with sarcoidosis and with silicosis were measured. Serum ACE was measured by enzymic assay and radioimmunoassay. There was a close relationship between ACE activity and content (r = 0.78). Serum ACE activities in patients with active sarcoidosis (37.5 +/- 11.1 nmol/min/ml, mean +/- SD) and with silicosis (25.5 +/- 9.3) were significantly elevated from the control (18.6 +/- 6.0). BALF ACE activities in the control, patients with active sarcoidosis and with silicosis were 0.23 +/- 0.19 nmol/min/ml, 0.94 +/- 0.97 and 0.38 +/- 0.05, respectively. BALF ACE in patients with active sarcoidosis and with silicosis were significantly different from the control. When BALF ACE was corrected by the cell count of alveolar macrophage (per 10(6) cells), activity was significantly different from control only in the patients with sarcoidosis. Moreover, only the alveolar macrophages in sarcoidosis were stained by immunofluorescence and immunocytochemistry using rabbit antihuman ACE antibody. Induction of ACE in alveolar macrophage might have an important role for the activity or progression of sarcoidosis.

Adult↗
PubMed1987

[Experimental study of intralymphatic chemotherapy in rabbits].

In order to examine the clinical usefulness of intralymphatic chemotherapy and the regimen of the appropriate anticancer drug for this route, we measured serum and tissue drug levels following intralymphatic administration of Futraful (FT) or Neocarzinostatin (NCS) in rabbits. The results were as follows: When a low-molecular-weight drug such as FT was administered into the lymphatic vessels, most of the drug flowed into the systemic circulation through the thoracic duct, but some leaked from the lymphatic vessels and flowed into the portal vein via the intestine. In the case of a high-molecular-weight drug such as NCS, there was a tendency for it to remain in the lymph nodes. It therefore seems that a drug of high molecular weight is most suitable for use in intralymphatic administration.

Animals↗
PubMed1987

[Evaluation of tumor marker CA15-3 in breast cancer].

CA15-3, a new tumor marker for breast cancer, was determined in various malignant diseases including breast cancer and various benign diseases, and its clinical significance and usefulness were studied. In 18 normal individuals, the value of CA15-3 was 8.9 +/- 3.3 U/ml (mean +/- SD). In primary breast cancer, the positivity was 20% for Stage I, 0% for Stages II and III and 100% for Stage IV. Of 17 cases of recurrent breast cancer, 13 (77%) were shown to be positive. The therapeutic effect and the value of CA15-3 were well correlated with each other. As for other malignant tumors, positive cases were observed in 50% of recurrent cancer of the stomach and in 14% of malignant tumors of the biliary system. All of these cases were terminal-stage cancers. The CEA value determined simultaneously showed a good correlation, r = 0.87 (p less than 0.01) with CA15-3 in malignant tumors other than breast cancer. In breast cancer, however, the correlation between the two was low, r = 0.18. These results suggest that CA15-3 is not necessarily useful in the diagnosis of primary breast cancer, but is useful as an indicator of the effect of therapy for recurrent breast cancer and for the prediction of recurrence.

Antigens, Neoplasm↗