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Biomedical subjects

Wei Yang

Publications and source records attributed to Wei Yang.

187 records · Page 11Linked to original sources
PubMed2002

[Effects of recombinant human brain natriuretic peptide and milrinone on cardiac hemodynamics and renal function in anesthetized dog].

AIM: To study the effects of rhBNP and milrinone on the cardiac hemodynamics and renal function in anesthetized dogs. METHODS: The actions of rhBNP given cumulatively i.v. 10, 30 and 100 ng.kg-1 for 30 min and milrinone of single dose (100 micrograms.kg-1, i.v.) on cardiac hemodynamics and renal function were studied in anesthetized open-chest dogs. RESULTS: In anesthetized dogs (n = 7) intravenous infusion of rhBNP at 10-100 ng.kg-1, caused decreases in mean arterial pressure (MAP), left ventricular systolic pressure (LVSP), LVdp/dtmax, pulmonary arterial pressure (PAP), left ventricular end diastolic pressure (LVEDP), total peripheral resistance (TPR) and renal vascular resistance (RVR) dose-dependently, without significant changes in cardiac output (CO), LV(dp/dt)/P, renal blood flow (RBF) and heart rate (HR), increases in urinary volume and sodium excretion. In anesthetized dogs (n = 6), there were remarkable decreases in MAP, LVEDP, PAP, TPR, RBF, RVR and urinary volume following the MIL (100 micrograms.kg-1, i.v.), with significant increases of LVSP, +/- LVdp/dtmax, HR and CO, but no marked changes in urinary volume and sodium excretion. CONCLUSION: rhBNP reduces the pre-load and after-load in the anaesthetized dogs but showed no distinct effect on the contractility of the heart. Positive inotropic and chronotropic actions have been demonstrated after intravenous injection of milrinone 100 micrograms.kg-1 in anesthetized dogs.

Anesthesia↗
PubMed2001

Hsc/Hsp70 interacting protein (hip) associates with CXCR2 and regulates the receptor signaling and trafficking.

The ligand-induced trafficking of chemokine receptors plays a significant role in the regulation of inflammatory processes and human immunodeficiency infection. Although many chemokine receptors have been demonstrated to internalize through clathrin-coated vesicles, a process that involves the binding of arrestins to the receptors, accumulating evidence has suggested the possible existence of other regulators. In a yeast two-hybrid screening using the C-terminal domain of CXCR2 as a bait, the Hsc70-interacting protein (Hip) was identified to interact with CXCR2. Hip binds CXCR2 through its C-terminal domain binding to the C-terminal leucine-rich domain (KILAIHGLI) of CXCR2. Hip associates with CXCR2 or CXCR4 in intact cells, and agonist stimulation increases the association. Mutation of the Ile-Leu motif in the C-terminal domain of CXCR2 blocks the agonist-dependent association of the mutant receptor with Hip. Overexpression of a tetratricopeptide repeat (TPR) deletion mutant form of Hip (Delta TPR), which is unable to bind Hsc70 (Prapapanich, V., Chen, S., Nair, S. C., Rimerman, R. A., and Smith, D. F. (1996) Mol. Endocrinol. 10, 420-431), but retains the ability to bind CXCR2, does not affect CXCR2-mediated mitogen-activated protein kinase activation. However, overexpression of Delta TPR significantly attenuates the agonist-induced internalization of CXCR2 and CXCR4 and attenuates CXCR2-mediated chemotaxis. These findings open the possibility for regulation of chemokine receptor signaling and trafficking by protein chaperone molecules.

Animals↗
PubMed2001

Coexpression of DNA Fragmentation Factor Subunits in E.coli by Two Incompatible Plasmids.

The human DNA fragmentation factor (DFF) is a heterodimer of 40 kD (DFF40/CAD) and 45 kD(DFF45/ICAD) subunits. Apoptotic DNA fragmentation and chromatin condensation are mediated by the caspase-activated DFF40 nuclease, which is inhibited by a chaperone-like subunit DFF45. In this work, the coding regions of human DFF45 and DFF40 mRNAs were amplified from total RNA of HeLa cells by RT-PCR. Two 1 kb DNA fragments were obtained and were cloned into a kanamycin-resistant bacterial expression vector, pET-28a( ), generating pET28a-DFF45 and pET28a-DFF40, which were then used to transform E.coli BL21(DE3), respectively. After induction with IPTG, DFF45 and DFF40 were expressed effectively, accounting for about 56% and 22% of total bacterial proteins, respectively. Since successful expression of properly folded DFF40 requires coexpression with DFF45, the full-length DFF45 cDNA was inserted into an ampicillin resistant expression vector, pET-21a( ), and the recombinant plasmid was designated pET21a-DFF45. Under screening pressure by ampicillin and kanamycin simultaneously, E.coli BL21(DE3) was cotransformed with pET21a-DFF45 and pET28a-DFF40. Upon induction with IPTG, DFF45 and DFF40 were coexpressed efficiently and the desired products comprised about 30% and 17% of total cell proteins, respectively. To further study the stability of the two incompatible plasmids'coexistance in E.coli, the cotransformant was cultured in liquid medium containing ampicillin and kanamycin for 14 h, and more than 75% of the cells were found to be resistant to the two antibiotics, that is, they carried both pET21a-DFF45 and pET28a-DFF40. Thus, a novel method of coexpressing different proteins using two incompatible plasmids was developed.

Journal Article↗
PubMed2001

Recombinant Human DFF45 Inhibits Apoptosis-specific Endonuclease in a Cell-free System of Xenopus Egg Extracts.

The human DNA fragmentation factor (DFF) is a heterodimer of 40 kD and 45 kD subunits. The 40 kD subunit (DFF40) has an intrinsic DNase activity responsible for the genomic DNA degradation into nucleosomal fragments during apoptosis. As an inhibitor for DFF40, the 45 kD subunit (DFF45) complexes with DFF40, inhibiting DNase activity until certain apoptosis signals are received. In cells undergoing apoptosis, the cleavage of DFF45 by activated caspase-3 frees DFF40from the complex and initiates the apoptosis-specific DNA fragmentation. In this report, the coding region of human DFF45 gene was amplified from the total RNA of HeLa cells by RT-PCR. The resulting 1 kb DNA fragment was cloned into the bacterial expression vector pET-28a(+) with a 6xhistidine tag fused to the N-terminus of DFF45, generating plasmid pET28a-DFF45, which was then used to transform E.coli BL21(DE3). Induced by IPTG, the recombinant DFF45 was expressed efficiently with a yield of 56.6% of total bacterial proteins. The product was purified to homogeneity through a nickel affinity column, followed by heat treatment, and approximately 4--6 mg of DFF was purified from 100 ml culture. Purified recombinant human DFF45, added into the apoptotic cell-free system of Xenopus egg extracts, could effectively inhibit both the digestion of lambdaDNA and the degradation of chromosomal DNA into nucleosomal fragments in the nuclei of chicken red blood cells. Our results demonstrated the existence of an apoptosis-specific endonuclease in this cell-free system, the activity of which could be inhibited by recombinant human DFF45.

Journal Article↗
PubMedDate not supplied

Differential display proteome analysis of PC-12 cells transiently transfected with metallothionein-3 gene.

Metallothionein-3 (MT-3), also known as growth inhibitory factor, possesses several unique properties other than the common features of metallothionein family. To investigate the mechanisms underlying its multifaceted roles in the central nervous system, we employed differential display proteomics techniques to study holistic protein changes of PC-12 cells induced by transient transfection of MT-3. Ten significantly and reproducibly changed proteins were identified and their functional implications are discussed in some detail.

Animals↗
PubMedDate not supplied

Yeast POL5 is an evolutionarily conserved regulator of rDNA transcription unrelated to any known DNA polymerases.

We show that yeast protein Yel055cp, which has been identified as the fifth essential DNA polymerase in Saccharomyces cerevisiae (POL5), is a member of a family of predicted rDNA transcription regulators (typified by human MYB-binding protein MYBBP1 A), which are represented by a single ortholog in all animals, fungi and plants with sequenced genomes. These proteins are confidently predicted to have an entirely a-helical structure and are unrelated to the B class DNA polymerases, as claimed for yeast POL5, or any other known polymerases.

Amino Acid Sequence↗