Biomedical subjects
Publications and source records attributed to J Xia.
The first examples of PEG linkers containing the highly fluorescent dansyl group have been synthesized. Quantum yields of these PEG fluorescent linkers (PFL) were determined and utilized in calculating the PEG number of various protein conjugates. The method was also shown to be applicable to lower molecular weight drugs as exemplified by taxol.
1. Neuropeptide Y (NPY; 3-100 nmol/L) caused a concentration-dependent potentiation of constriction in response to noradrenaline or the thromboxane mimetic U46619 in arterioles from the submucosa of the guinea-pig small intestine. 2. In arterioles permeabilized by exposure to the alpha-toxin of Staphylococcus aureus and maintained in Ca(2+)-buffered medium, NPY potentiated the contractile effects of Ca2+. The magnitude of the potentiation was the same as in intact arterioles. 3. Exposure of arterioles to 1 mumol/L nifedipine to inhibit Ca2+ influx or to 20 mumol/L cyclopiazonic acid to abolish Ca2+ uptake into internal stores had no effect on the potentiating action of NPY.
To determine a fetal variable number of tandem repeats (VNTR) without using fetal tissues, we amplified the whole VNTR region in intron 40 of the von Willebrand factor gene from maternal peripheral blood by the polymerase chain reaction and then separated the amplified fragments by a nonhydratable polyacrylamide gel with an electrolyte gradient. After water elution from the gel, each preliminary product was amplified for the second time and then digested by Alu I restriction endonuclease. Then the VNTR was examined using a hydratable polyacrylamide gel with an electrolyte gradient. We successfully identified the fetal VNTR from 6 cases of 10 maternal peripheral blood samples and 2 cases of 6 maternal blood samples after parturition. This study might offer a theoretical basis for the noninvasive diagnosis of genetic disorders and identification of disputed paternity with common primers.