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Biomedical subjects

T Yamura

Publications and source records attributed to T Yamura.

At least 19 recordsLinked to original sources
PubMed1982

Isolation of tissue plasminogen activator from skin lesions with allergic vasculitis.

A tissue plasminogen activator was extracted from skin lesions with allergic vasculitis and purified by successive column chromatography on Sephadex G-200, DEAE-cellulose, Hydroxyaptite-cellulose and polyacrylamide gel electrophoresis. By these procedures, 160 micrograms of enzyme with a specific activity of 843.8 international units/mg protein was obtained from 5 g of original skin. The purified material was homogeneous as ascertained by sodium dodecyl sulfate polyacrylamide gel electrophoresis and had an apparent molecular weight of 110,000 as measured by gel filtration on Sephadex G-200. Its identity with human urokinase was investigated and was found to possess the same plasminogen activator activity as that of urokinase. It had high amindolytic activity, but only slight N-alpha-acetyl-glycyl-L-lysine methyl ester esterolytic activity. This tissue plasminogen activator was confirmed to be immunologically identical to human urokinase.

Aged↗
PubMed1981

The significance of cell-bound antigen-specific IgE in chronic urticaria.

Radioallergosorbent test (RAST) was performed on the sera obtained from chronic urticarial patients from whose leucocytes significant histamine release by mite antigen was observed. In 14 out of 19 cases investigated, no mite-antigen-specific IgE was detected in their sera by RAST, in spite of significant mite-antigen-induced histamine release from their leucocytes. The results suggest that type I reaction may be involved in chronic urticaria and the cell-bound, antigen-specific IgE may be important rather than the circulating antigen-specific IgE in this disease.

Adolescent↗
PubMed1980

Further studies on a new kallikrein inhibitor in human skin--its purification and characterization.

A new kallikrein inhibitor in human skin extract was further purified by successive column chromatography on DEAE-cellulose, hydroxylapatite-cellulose, and p-cellulose. By these procedures, 0.7 mg of purified preparation was obtained from 10 g of original skin. The purified material was homogeneous, as confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and ultracentrifugation. It had an S20,w value of 4.2 and an apparent molecular weight of 57,000 as measured by gel filtration on Sephadex G-200, and was heat unstable. It possessed an inhibitory activity towards not only human plasma kallikrein, but also human urinary and pancreas kallikrein. It also exhibits antiplasmin and antithrombin activity. This kallikrein inhibitor was found to be immunologically distinct from alpha 2-macroglobulin, alpha 1-antitrypsin, or Cl-inhibitor.

Chromatography, DEAE-Cellulose↗
PubMed1980

Studies on the blood fibrinolytic enzyme system of patients with cutaneous vasculitis.

The fibrinolytic enzyme system in thirty-two patients suffering from cutaneous vasculitis was investigated. In five of seven patients with Behçet's disease and in five of thirteen patients with erythema nodosum a significant elongation of euglobulin lysis time was observed. On the other hand, in two patients with allergic vasculitis, a significant shortening of euglobulin lysis time was noticed. In the present study, factors responsible for the change of euglobulin lysis time were sought. It was confirmed that the significant elongation of euglobulin lysis time in patients with erythema nodosum was based on an increase of fibrinogen content in the euglobulin fraction. On the other hand, it was speculated that the significant elongation of euglobulin lysis time in patients with Behçet's disease might be due to an increase of antiactivators in the patients' plasma. In the present study, the authors further investigated the status of this antiactivator which is increased in plasma of patients with Behçet's disease, and proposed the possibility that the increased antiactivator might consist of at least two types of antiactivators, one of which is considered to be alpha 2-plasmin inhibitor.

Adolescent↗
PubMed1979

Kinin-forming enzyme in human skin: the purification and characterization of a kinin-forming enzyme.

A kinin-forming-enzyme in human skin extract was further purified by successive column chromatography on DEAE-cellulose, Hydroxylapatite-cellulose and Sepharose-4B. By these procedures, 2.7 mg of purified enzyme was obtained from 10 gm of original skin. The purified material was homogeneous as ascertained by cellulose acetate membrane electrophoresis, sodium dodecyl sulfate polyacrylamide gel disc electrophoresis and ultracentrifugation. It had an S20,w value of 4.3 and an apparent molecular weight of 104,000 as measured by gel filtration on Sephadex G-200. The purified enzyme was comparatively heat-stable, but was unstable below pH values of 5 and above pH 9. It possessed arginine or lysine esterolytic activity, but not tyrosine or tryptophane esterolytic activity and denatured proteolytic activity. This enzyme was not affected by metal ion, cystein, glutathion or rho-chloromercuribenzoate, but was strongly inhibited by alpha-N-rho-tosyl-L-lysine chloromethyl ketone or soybean-trypsin inhibitor. It was also inhibited by alpha 1-antitrypsin, but not by alpha 2-macroglobulin. This enzyme was confirmed to be immunologically distinct from human plasma, urinary or pancreas kallikrein.

Animals↗
PubMed1979

In vitro release of eosinophil chemotactic factor of anaphylaxis (ECF-A) from guinea pig skin.

An in vitro release of the eosinophil chemotactic factor of anaphylaxis (ECF-A) in anaphylactic reactions was studied using skin slices from actively sensitized guinea pigs. ECF-A and histamine were released in vitro from actively sensitized guinea pig skin by antigen challenge. The magnitude of ECF-A release did not always parallel that of anaphylactic histamine release in guinea pig skin, suggesting that there may be no correlation between the amount of ECF-A and that of histamine released from the skin in anaphylactic reactions in guinea pigs.

Anaphylaxis↗
PubMed1979

The role of mite allergen in chronic urticaria.

Fifty-two patients with chronic urticaria were tested intradermally with mite allergen (Dermatophagoides farinae). None had any past history of any other atopic diseases. Thirty of the 52 patients gave positive skin tests to mite allergen. A good correlation between skin sensitivity to mite allergen and in vitro mite antigen-induced histamine release from leucocytes was observed. These facts suggest that a mite may be an important role in chronic urticaria.

Allergens↗
PubMed1978

Studies on the effect of plasminogen activator on the interaction between alpha 2-macroglobulin and plasmin.

Six different plasmins were prepared by incubating human plasminogen with various amounts of streptokinase or urokinase. It was confirmed that the six different plasmins possessed similar caseinolytic activities, and the inhibitory effects of a alpha 1-antitrypsin on caseinolytic activities of the six different plasmins were all the same. On the other hand, interactions between the six different plasmins and alpha 2-macroglobulin were complicated. Plasmins activated by cleavage of plasminogen were almost immediately or effectively inhibited by alpha 2-macroglobulin. However, plasmin activated by complex formation of plasminogen with streptokinase was not so immediately or effectively inhibited by alpha 2-macroglobulin. It was supposed that the difference between these two results on the interaction between plasmin and alpha 2-macroglobulin might be due to the difference in molecular form of plasmin. In the present study, it was also confirmed that streptokinase or urokinase, in free form in the reaction mixture, interfered with the interaction between plasmin and alpha 2-macroglobulin. The cause for such interference was discussed.

Fibrinolysin↗