Biomedical subjects

J Z Tan

Publications and source records attributed to J Z Tan.

9 recordsLinked to original sources

PubMed1999

[Western blotting of RStV gene products in rice and insects].

The NS3 and NC protein genes encoded by RNA3 of RStV, the NCP and NSvc4 protein genes encoded by RNA4 were subcloned into the E. coli expression vector pGEX3X to express four groups of fusion protein under IPTG induction. These fusion proteins were used to immunize rabbits to raise antisera. The antisera against the E. coli-expressed proteins were available for probing the presence of the viral gene products in both rice plant and insect hosts. The expected gene products can be probed only in diseased rice plant with NCP antiserum and the corresponding products detected in both plant and RStV particle preparation with NC antiserum. The viral gene products probed by NS3 and NSvc4 antisera were different from the expected ones in size.

Animals↗

PubMed1997

Cloning of a gene (RIG-G) associated with retinoic acid-induced differentiation of acute promyelocytic leukemia cells and representing a new member of a family of interferon-stimulated genes.

In a cell line (NB4) derived from a patient with acute promyelocytic leukemia, all-trans-retinoic acid (ATRA) and interferon (IFN) induce the expression of a novel gene we call RIG-G (for retinoic acid-induced gene G). This gene codes for a 58-kDa protein containing 490 amino acids with several potential sites for post-translational modification. In untreated NB4 cells, the expression of RIG-G is undetectable. ATRA treatment induces the transcriptional expression of RIG-G relatively late (12-24 hr) in a protein synthesis-dependent manner, whereas IFN-alpha induces its expression early (30 min to 3 hr). Database search has revealed a high-level homology between RIG-G and several IFN-stimulated genes in human (ISG54K, ISG56K, and IFN-inducible and retinoic acid-inducible 58K gene) and some other species, defining a well conserved gene family. The gene is composed of two exons and has been mapped by fluorescence in situ hybridization to chromosome 10q24, where two other human IFN-stimulated gene members are localized. A synergistic induction of RIG-G expression in NB4 cells by combined treatment with ATRA and IFNs suggests that a collaboration exists between their respective signaling pathways.

Amino Acid Sequence↗

PubMed1997

Nitric oxide and prostaglandins mediate vasodilation to 5,6-EET in rabbit lung.

We have previously found that 5,6-EET (epoxyeicosatrienoic acid)(50 nM) significantly dilates the vascular bed(42%) of the isolated, constantly perfused rabbit lung, which has been constricted with U46619(5-8 pM). We studied the role of EDRF-NO and prostaglandins in the 5,6-EET-induced vascular relaxation. Dilation to 5,6-EET was evident only when the pulmonary vascular tone was increased. L-NNA (N omega-nitro-L-arginine, 10(-4) M), an inhibitor of NO synthase(NOS); U46619(5-10 pM), a thromboxane mimetic; and L-NNA + INDO(indomethacin, 10(-5) M), a cyclooxygenase inhibitor, all increased the pressure of pulmonary artery(PPa) from baseline, to a peak range of 28-38mmHg(32.75 [symbol: see text] 2.2), whereas INDO alone increased Ppa only by 10mmHg. L-NNA + INDO,L-NNA alone, and INDO + U46619 attenuated the 5,6-EET relaxing effect by 100%, 88% and 64.5%, respectively. In the presence of L-NNA and 5,6-EET, SNAP(S-nitroso-N-acetyl-D,L-penicillamine, 10(-6) M), a NO donor, reduced Ppa by 75%. We conclude that the mechanism of vasodilation to 5,6-EET in the rabbit pulmonary circulation is via both EDRF-NO and PG pathways and that the vasodilation is largely EDRF-NO dependent.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1996

RIG-E, a human homolog of the murine Ly-6 family, is induced by retinoic acid during the differentiation of acute promyelocytic leukemia cell.

In vivo all-trans-retinoic acid (ATRA), a differentiation inducer, is capable of causing clinical remission in about 90% of patients with acute promyelocytic leukemia (APL). The molecular basis for the differentiation of APL cells after treatment with ATRA remains obscure and may involve genes other than the known retinoid nuclear transcription factors. We report here the ATRA-induced gene expression in a cell line (NB4) derived from a patient with APL. By differential display-PCR, we isolated and characterized a novel gene (RIG-E) whose expression is up-regulated by ATRA. The gene is 4.0 kb long, consisting of four exons and three introns, and is localized on human chromosome region 8q24. The deduced amino acid sequence predicts a cell surface protein containing 20 amino acids at the N-terminal end corresponding to a signal peptide and an extracellular sequence containing 111 amino acids. The RIG-E coded protein shares some homology with CD59 and with a number of growth factor receptors. It shares high sequence homology with the murine LY-6 multigene family, whose members are small cysteine-rich proteins differentially expressed in several hematopoietic cell lines and appear to function in signal transduction. It seems that so far RIG-E is the closest human homolog of the LY-6 family. Expression of RIG-E is not restricted to myeloid differentiation, because it is also present in thymocytes and in a number of other tissues at different levels.

Amino Acid Sequence↗

PubMed1995

Perspectives on genetics in china.

The long civilization of China traces its origin to the development of agriculture. Early records and archaeological findings demonstrate the success of plant and animal breeding in contributing to human livelihood and the national economy. Teaching and research in modern genetics began in China in the 1920s with individuals who received advanced training in the West. Over the following 30 years, notable contributions to genetics, both basic and applied, were made by Chinese scientists in universities and research institutions. Unfortunately, these activities were brought to a virtual standstill first by the official advocacy of Lysenkoism, followed by ten years of Cultural Revolution. Schools were closed and scientific research was interrupted. Not until 1978 did the universities begin to enroll new students and scientific research, including genetics, again receive endorsement. Since then, Chinese scientists have resumed contacts with colleagues in other countries and publication of their research findings in national and international journals. The material summarized in this article covers a long time span and a broad spectrum of scientific subjects and events. Representative examples of Chinese contributions to various areas of genetics are cited to depict the history, current status, and prospects for the development of genetics in China. After many ups and downs and despite limitations in material resources, the study of genetics in China seems to be on a sound footing, with a relatively complete system in place for training workers in this discipline.

Agriculture↗

PubMed1992

Open method versus capsulorrhaphy without drainage in the treatment of children with hepatic hydatid disease.

A recognized major postoperative complication of hepatic hydatid disease is accumulated hydrops leading to secondary infection in the residual cavity of the excised cyst. This study examined two methods of treating cystic hepatic hydatid disease in 43 children. A group of 22 children were treated by a new method of open drainage, 21 underwent capsulorrhaphy without drainage. There was no mortality or morbidity. The open method was associated with more rapid resolution of hydrops and quicker shrinkage of residual cavities, with efficacy over a median follow-up of 42 months.

Adolescent↗

PubMed1989

Identification of partial mutational sites in human mitochondrial DNA in the Chinese and its significance.

A simple method for the identification of mutational sites in human mitochondrial DNA (mtDNA) was described. It was based on the human Cambridge sequence as a relative standard sequence and a single base pair substitution in mtDNA as a unique mutational form. The partial mutational sites can be determined using this method which was characterized by combining the restriction mapping with the analysis for the table of human mtDNA potential mutational sites with rapidity and simplicity. In the meanwhile, six mtDNA mutational sites found in Chinese population were identified by means of this method.

China↗

PubMed1989

[Study on genetic polymorphism of isozyme in natural populations of Drosophila virilis].

Using techniques of polyacrylamide slab electrophoresis and agarose electrophoresis, we have detected genetic variation at 6 loci which coding for enzymes in 4 local samples from natural population of Drosophila virilis. We found 50% of the loci detected are polymorphic, depending on the criterion of polymorphism used. An individual is heterozygotes on the average at 27.13% of its loci. The amount of genetic variation fluctuates widely from locus to locus. At Est-alpha, Est-beta, Amy, most of the individuals are heterozygotes. At the other extreme , Mdh, aGpdh, Acph, few individuals are heterozygotes. For Mdh, we have measured the thermostability at 53 degrees C. No more genetic variation was found. We have measured the amount of genetic differentiation between different local populations. The result showed that there is no relationship between geographical distance and genetic distance. The results are discussed in the light of the continuing controversy over selection and natural theories of genetic variation. We think that both selection and stochastic processes must operate simultaneously in most systems.

Animals↗

PubMed1988

Mitochondrial DNA polymorphism in Chinese.

Human mitochondrial DNA (mtDNA) restriction endonuclease fragment patterns were analyzed using placenta DNA isolated from 273 individuals representing four different nationalities, the Han, the Uygur, the Kazakh and the Hui populations. Thirty-eight fragment patterns (morphs) were observed with the enzyme ApaI, BamHI, EcoRI, HindIII, HinfI, HhaI, HapII, KpnI, Mbol, PstI, PvuII, SacI, ScaL and XhoI. Fourteen new morphs, including some only existing in individual racial and national populations were observed, which indicates that there is a significant difference in the distribution of mtDNA morphs among various national and racial populations. By comparison with the mtDNA sequences in primate species, some mtDNA ancestral morphs were found to be retained in Oriental population today. This result provided indirect evidence that Asia may be one of the human original sources. Genetic distances among four national populations computed and employed in construction of an average linkage tree suggested that the Uygur and the Kazakh populations combined to form a branch at first, then the Han and the Hui came together to form another one, and at last, these two branches converged into a stem. Again, it was found that the internal variation within the Uygur and the Kazakh populations was greater than that within the Han and the Hui populations. These results showed a relationship among the four different national populations in China based on the molecular level.

China↗