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Biomedical subjects

X Y Yang

Publications and source records attributed to X Y Yang.

120 records · Page 7Linked to original sources
PubMed1984

Synthesis of the leu-enkephalin gene.

The synthesis of Leu-enkephalin gene by an alternative approach was described in this paper. The sequence of the synthetic gene, 26 base-pairs in length, was derived from the amino acid sequence of the hormone peptide Leu-enkephalin. It bears single-stranded cohesive termini for the restriction endonucleases EcoR I and BamH I so that it may be inserted into a pBR 322 plasmid. The 4 deoxyoligonucleotide fragments, varying in length from octanucleotide to octadecanucleotide, were synthesized by an improved phosphotriester method developed in our laboratory. All chemically synthetic fragments were pure and had the correct sequences. The assembly of the Leu-enkephalin gene was carried out in a one-step ligation reaction catalysed by T4-DNA ligase with good yield. Finally, the purified products from polyacrylamide gel electrophoresis had the correct joining-points as predicted.

DNA Ligases↗
PubMed1979

Studies on a new antiarrhythmic drug changrolin-4-(3',5'-bis [(N-pyrrolidinyl) methyl]-4'-hydroxyanilino)-quinazoline.

Changrolin is 4-(3', 5'-bis[(N-pyrrolidinyl)methyl]-4'-hydroxyanilino)-quinazoline. It is a novel type of antidysrhythmic drug. It has been synthesized in 4 steps. According to our experiments, changrolin exhibited significant protective and therapeutic effects against experimental arrhythmias induced by aconitine or ouabain. It raised the electrical threshold of ventricular fibrillation. Intravenous injections in dogs and rabbits caused (i) a mild tachycardia followed by bradycardia; (ii) a prolongation of P-R interval and a widening of QRS complex in the electrocardiogram; (iii) a gradual hypotehsion; (iv) a slight weakening of cardiac functions; and (v) only moderate influences on the hearts of dogs and rabbits when the rate of infusion was less than 1 mg/min. Changrolin could be well absorbed by oral administration. Absorption appeared to be more rapid and complete by intramuscular injection. 14C-labelled changrolin was distributed mainly in the liver and the alimentary tract.

Animals↗