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Biomedical subjects

J K Wong

Publications and source records attributed to J K Wong.

6 recordsLinked to original sources
PubMed1991

Discovery and preliminary pharmacology of Sch 37370, a dual antagonist of PAF and histamine.

From a series of amide analogs of the histamine H1 antagonist, azatadine, a potent, orally active, dual platelet-activating factor (PAF) and histamine antagonist, Sch 37370, namely 1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo- [5,6]cyclohepta[1,2-b]pyridin-11-ylidine)piperidine, was discovered. Sch 37370 selectively inhibits PAF-induced aggregation of human platelets in vitro (IC50 = 0.6 microM), and in vivo inhibits PAF- and histamine-induced bronchospasm in guinea pigs with ED50 values of 6.0 and 2.4 mg/kg p.o., respectively. Sch 37370 is expected to be more efficacious than single mediator antagonists in allergic diseases, such as asthma.

Histamine Antagonists↗
PubMed1990

Short-term effect of hepatic arterial versus portal venous reperfusion on energy levels of liver tissue.

The hepatic artery and the portal vein blood vary in flow, oxygenation, and hormonal content. It was uncertain which blood supply has a greater effect on the recuperative process of the hepatocytes in the ischemic liver during the initial reperfusion. The ability of the liver cells to restore its energy phosphates is related to the viability of the liver. This study was designed to determine the differences of the high energy phosphate in the liver predicated upon whether reflow was first provided by either the hepatic artery or the portal vein followed by subsequent reperfusion from both vessels. The recovery of ATP upon 10 min of only hepatic arterial reperfusion after 15 min of total ischemia was much slower compared to the portal venous reperfusion only. It may be undesirable, therefore, to reperfuse the liver with hepatic arterial blood first immediately after warm liver ischemia.

Adenine Nucleotides↗
PubMed1989

Drugs of abuse found in fatally injured drivers in Los Angeles County.

Blood or urine specimens from nearly 600 fatally injured drivers in two Los Angeles County studies were analyzed for the presence of alcohol and other drugs of abuse, including PCP, cocaine, opiates and marijuana. The results of the preliminary study indicate that 65 out of 102 fatally injured drivers had used alcohol and/or another drug of abuse - 34 had used alcohol only, 12 had used one or more other drug(s) of abuse, and 19 had used alcohol in combination with another drug of abuse. The results of the larger follow-up study, begun a year later, indicate a continued high level of both alcohol use (41.5%) and marijuana use (19%) with moderate cocaine usage (8%) and low levels (less than 2%) of barbiturate and PCP usage.

Accidents, Traffic↗
PubMed1988

The C-terminal domain of the largest subunit of RNA polymerase II of Saccharomyces cerevisiae, Drosophila melanogaster, and mammals: a conserved structure with an essential function.

Using DNA encoding the largest subunit of Drosophila melanogaster RNA polymerase II, we isolated the homologous hamster RPO21 gene. Nucleotide sequencing of both the hamster and D. melanogaster RPO21 DNAs confirmed that the RPO21 polypeptides of these two species, like the Saccharomyces cerevisiae RPO21 polypeptide, contain both an N-terminal region homologous to the Escherichia coli RNA polymerase subunit beta' and a unique polymerase II-specific C-terminal domain. This C-terminal domain, encoded by separate exons in the D. melanogaster and hamster genes, consists of a tandemly repeated heptapeptide sequence. By constructing a series of deletions in DNA encoding the 26 heptapeptide repeats normally present in the S. cerevisiae RPO21 polypeptide, we have established that a minimum of between 9 and 11 repeats is necessary for RPO21 function in yeast cells. Replacement of the yeast RPO21 heptapeptide repeats by the longer hamster repetitive domain resulted in viable yeast cells with no detectable mutant phenotype, while a similar replacement of the yeast repeats by the more divergent D. melanogaster repeats was a recessive lethal mutation. We suggest that this novel repetitive domain is essential for proper initiation of transcription by RNA polymerase II and that it may mediate the functions of TATA boxes, upstream activating sequences, and enhancers.

Amino Acid Sequence↗
PubMed1979

Examination hints.

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Education, Nursing↗