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Biomedical subjects

S C Lin

Publications and source records attributed to S C Lin.

At least 217 records · Page 12Linked to original sources
PubMed1978

Purification and characterization of the anticoagulant principle of Trimeresurus mucrosquamatus venom.

By means of CM-Sephadex column chromatography, Trimeresurus mucrosquamatus venom was separated into 20 fractions. Fraction XX had the marked anticoagulant action. This fraction was refractionated three times on Sephadex G-75, and a single peak was obtained. The patterns of microzone and disc electrophoresis also showed a single band. A single, symmetrical boundary with a value of 1.61 S was obtained by ultracentrifugation. It was a single peptide chain with a molecular weight of 11 700. The isoelectric point was higher than pH 10. The anticoagulant principle possessed phospholipase A activity and was calcium ion dependent. It did not possess proteolytic, tosyl-L-arginine methyl ester esterase, phosphodiesterase and alkaline phosphomonoesterase activities of the crude venom. The phospholipase A activity was heat-labile at pH 7.4, but was heat-stable at pH 5.6. The anticoagulant activity was more resistant to heat treatment as compared with phospholipase A activity. The anitoagulant action of the purified principle was competitively inhibited by platelet phospholid, tissue thromboplastin and cephalin, and was neutralized by antiserum. The anticoagulant principle inhibited platelet aggregation induced by ADP. It did not destroy fibrinogen, Factor X, prothrombin and thrombin; nor did it induce fibrinolysis nor interfere with the interaction between thrombin and fibrinogen. It is concluded that the anticoagulant action of this phospholipase A was due to the inhibition of the activations of Factors X and II through the inactivation of the procoagulant activity of phospholipids mediated partly by phospholipid-binding activity of this venom enzyme and partly by its enzymatic hydrolysis of phospholipids.

Amino Acids↗
PubMed1977

Regional distribution of barbital in the brain of mice during the development of tolerance and physical dependence.

ICR male mice each receiving a 16 mg barbital pellet implanted subcutaneously for three days developed about 40 percent tolerance to barbital and more than 50 percent tolerance to pentobarbital as measured by sleeping time. The development of physical dependence in these mice was demonstrated by an increased sensitivity to convulsions with pentylenetetrazol. The concentration of barbital rose to high levels in the subcortex and the cerebellum during the time between the implantation of the pellet and the loss of the righting reflex and distributed uniformly thereafter. After a challenge dose of the drug, higher barbital concentrations were found in these two areas as well as in the pons-medulla at 30 minutes and in all areas at the time of the loss of righting reflex, in withdrawn mice. The latter finding would indicate an increase in threshold for barbital anesthesia. The mechanisms of the higher uptake in the brain of withdrawn mice are discussed.

Animals↗
PubMed1976

Distribution of the femoral circulation in living dogs.

The femoral circulation of living dogs was studied with plastic carbonized microspheres 50 and 200 micra in diameter, labeled with Yterbium169. The femoral blood flow is distributed in the following way: 35% of the particles 50 micra in diameter went to muscle, 45% of the same particles went to skin and 20% to bone. When the particles were 200 micra in diameter 16% went to muscle, 65% to skin and 19% to bone.

Animals↗
PubMed1974

Perfusion and ventilation scintigrams with a gamma-camera.

Regional lung function studies were obtained with a gamma camera. The ventilation was studied with 133Xe and radioactive particles and the pulmonary circulation with radioactive particles and the pulmonary circulation with radioactive particles. Some pathophysiologic patterns could be defined with this methodology, i.e. in chronic uncomplicated pulmonary embolism the pathophysologic pattern was normal ventilation with decreased or absent perfusion in the affected areas, when C.O.L.D. was associated with pulmonary embolism the ventilation with 133Xenon could be normal if the C.O.L.D. was mild but the inhaled particles deposited in foci. In bullous disease the inhaled 133Xenon reached the blebs with delay and that wash-out was prolonged, the particles did not reach the blebs, the perfusion was absent in the areas with blebs. Similar pattern was present in bronchial obstruction. In hilar masses the defect in perfusion and ventilation was usually larger than the one expected from the lesion.

Albumins↗