Biomedical subjects

Xiao-Ming Yang

Publications and source records attributed to Xiao-Ming Yang.

11 recordsLinked to original sources

PubMed2006

A molecular epidemiological study targeting the glycoprotein gene of rabies virus isolates from China.

A group of 31 rabies viruses (RABVs), recovered primarily from dogs, one deer and one human case, were collected from various areas in China between 1989 and 2006. Complete G gene sequences determined for these isolates indicated identities of nucleotide and amino acid sequences of >or=87% and 93.8%, respectively. Phylogenetic analysis of these and some additional Chinese isolates clearly supported the placement of all Chinese viruses in Lyssavirus genotype 1 and divided all Chinese isolates between four distinct groups (I-IV). Several variants identified within the most commonly encountered group I were distributed according to their geographical origins. A comparison of representative Chinese viruses with other isolates retrieved world-wide indicated a close evolutionary relationship between China group I and II viruses and those of Indonesia while China group III viruses formed an outlying branch to variants from Malaysia and Thailand. China group IV viruses were closely related to several vaccine strains. The predicted glycoprotein sequences of these RABVs variants are presented and discussed with respect to the utility of the anti-rabies biologicals currently employed in China.

Amino Acid Sequence↗

PubMed2006

A method for purification and viral inactivation of human placenta hemoglobin.

For pilot-scale manufacturing of hemoglobin-based oxygen carrying drugs, we should get highly pure and viral inactivated hemoglobin (Hb) at high recovery. In our method, placenta hemoglobin (PHb) solutions were purified by heating in the presence of reducing agent and deoxygenating conditions so that heat-sensitive proteins were selectively precipitated and virus was inactivated. The optimum preparative condition resulted in highly purified PHb solution (>99% pure) with approximate 90% recovery and less than 2% of MetHb content, maintained oxygen carrying capacity, residual phospholipids less than 1 ppm, free of endotoxin, bacteria, type A&B antigens and virus. Finally, we compared the efficacy of blood exchange on rat with poly-PHb and poly-Hb from adult blood. The results showed no significant difference between two products. Therefore, the placenta Hb obtained from this method could be supplied as materials for oxygen carrying drugs.

Animals↗

PubMed2006

Rapid induction and activation of Tec tyrosine kinase in liver regeneration.

BACKGROUND: Previous studies have indicated that Tec tyrosine kinase is differentially expressed in the regenerating liver. The purpose of the present study was to further investigate the potential involvement of Tec tyrosine kinase in hepatocyte proliferation and liver regeneration. METHODS: Tec kinase gene expression after partial (two-thirds) hepatectomy was examined by representational difference analysis. Tissue distribution and potential involvement of Tec kinase in liver regeneration and hepatocyte proliferation were then determined by northern blotting, reverse transcription-polymerase chain reaction (RT-PCR), and western blotting. Full-length rat Tec cDNA was cloned. RESULTS: Using this cDNA as the probe, northern blotting showed that Tec was specifically expressed in liver and kidney, the highest expression of Tec being detected in embryonic day 15-19 fetal livers. In contrast, the expression level of Tec in adult and neonatal rat livers was significantly decreased. Similar results were obtained from western blotting analyzes. It was thus hypothesized that Tec might be involved in hepatocyte proliferation. To test this hypothesis, Tec expression was examined in regenerating rat livers. An increase in Tec expression and activation of Tec kinase were observed within 1 h after partial hepatectomy. Moreover, it has been shown that hepatocyte growth factor (HGF) dramatically induces Tec expression in primary rat hepatocytes. Additionally, it was observed that Tec gene expression in serum-starved liver tumor cell line HepG2 was substantially decreased. Stimulation with 10% fetal bovine serum and insulin but not epidermal growth factor resulted in dramatic elevation of Tec expression in these cells. CONCLUSION: Tec is an inducible early response gene that might enhance hepatocyte proliferation and liver regeneration.

Animals↗

PubMed2004

[Expression of EDAG-1 gene in human leukemia and lymphoma cell lines].

BACKGROUND & OBJECTIVE: Embryonic development associated gene 1 (EDAG-1), located at chromosome 9q22, is specially expressed in hematopoietic cells, and related to the regulation of hematopoietic system. This study was designed to explore relationship between pathogenesis of leukemia, lymphoma and EDAG-1 through analyzing the structure of EDAG-1 coding region, and its expression in these cell lines. METHODS: Fifteen leukemia and lymphoma cell lines, HEL, K562, HL-60, Namalwa, Raji, J111, Jurkat, HuT 78, MEG-01, U937, 6T-CEM, HPB-ALL, KG-1a, THP-1, and DAMI, were selected to observe the expression of EDAG-1 by reverse transcriptase-polymerase chain reaction (RT-PCR), EDAG-1 cDNA coding fragments (1.5 kb) were purified to construct the corresponding recombinant plasmid. Then, the plasmid was sequenced to analyze mutation of the coding region. The expression of EDAG-1 protein, and mRNA in these cell lines were detected by Western blot, and Northern blot; the rearrangement and amplification of EDAG-1 genome in these cell lines were detected by Southern blot. RESULTS: EDAG-1 mRNA and protein were highly expressed in erythroleukemia cell lines (K-562, HEL), megakaryoblast leukemia cell lines (DAMI, MEG-01), and T cell leukemia cell line (Jurkat), while no gene mutation was found in coding region, no amplification and rearrangement of genome was detected in these cell lines. EDAG-1 was absent in HL-60 cell line, and rearranged in HuT 78 cells. CONCLUSION: EDAG-1 may relate with pathogenesis of erythroleukemia and megakaryoblast leukemia; its coding region may have no relation with the mechanism of its activation.

Burkitt Lymphoma↗

PubMed2002

Identification and characterization of a novel isoform of hepatopoietin.

AIM: To isolate a novel isoform of human HPO (HPO-205) from human fetal liver Marathon-ready cDNA and characterize its primary biological function. METHODS: 5'-RACE (rapid amplification of cDNA 5' ends) was used to isolate a novel isoform of hHPO in this paper. The constructed pcDNA(HPO-205), pcDNA(HPO) and pcDNA eukaryotic expression vectors were respectively transfected by lipofectamine method and the stimulation of DNA synthesis was observed by (3)H-TdR incorporation assay. Proteins extracted from different cells were analyzed by Western blot. RESULTS: A novel isoform of hHPO (HPO-205) encoding a 205 amino acid ORF corresponding to a translated production of 23 kDa was isolated and distinguished from the previous HPO that lacked the N-terminal 80 amino acids. The dose-dependent stimulation of DNA synthesis of HepG2 hepatoma cells by HPO-205 demonstrated its similar biological activity with HPO in vitro. The level of MAPK (Mitogen-activated protein kinase) phosphorylation by Western blot analysis revealed that HPO-205 might have the stronger activity of stimulating hepatic cell proliferation than that of HPO. CONCLUSION: A novel isoform of hHPO (HPO-205) was isolated from hepatic-derived cells. The comparison of HPO-205 and HPO will lead to a new insight into the structure and function of hHPO, and provide the new way of thinking to deeply elucidate the biological roles of HPO/ALR.

Amino Acid Sequence↗

PubMed2002

[Surgical approach in plastic of shortened lower limb].

OBJECTIVE: To introduce a new surgical approach to rectify the shortened lower limbs. METHODS: From March 1985 to October 2000, 288 cases of shortened lower limbs were treated and reviewed. Closed fracture at the metaphysis was made by a self-made "needle saw", and then the "multiple-plane and double-track elongation instrument" was adopted to elongate the fractured bone. There were totally 161 cases of male and 127 cases of female included, with average age 21.3 years old, ranging from 12 to 29 years old, among which there were 268 cases elongated at the proximal metaphysis of the tibia, 16 cases at the distal femur and 4 cases at the distal tibia. All of the cases were followed up for 6 to 8 months before clinical evaluation. RESULTS: The lower limbs in 288 cases were elongated for 3.0 to 11.5 cm in 24 to 96 days, averaging 47 days, which fulfilled pre-operative plan. In the second week after the operation, new calculus and periosteum formed obviously in the gap between the fractured parts, and in 6 to 8 months bone union was observed at the fractured site in all cases. There was no nerve or blood vessel injury, or non-union of the metaphysis fracture. The function of the manipulated knee joints and ankle joints recovered well. CONCLUSION: It is a practical and safe surgical option to rectify the shortened lower limbs by closed fracture at the metaphysis, followed by elongation of the fractured bone, without any complication such as non-union or atrophy of manipulated bone, and with no need of internal fixation or bone grafting.

Adolescent↗

PubMed2002

[Overexpression of EDAG-1 in NIH3T3 cells leads to malignant transformation].

To study the biological function of EDAG-1, a novel gene cloned by our lab recently, the EDAG-1 cDNA was subcloned into pcDNA3. 1(+) vector and transfected into NIH3T3 cells by Lipofect AMINE methods. Overexpression of EDAG-1 in NIH3T3 cells resulted in loss of cell contact inhibition, anchorage-independent growth in soft agar and tumor formation in nude mice. These results suggest that EDAG-1 is a transforming gene and may be associated with the development of tumors, especially in hematopoietic system.

3T3 Cells↗

PubMed2002

[The thinking about modern biological technology].

The way of life and mode of thinking of mankind is being changed by modern biological technology. It may be come true again that coexist and evolution of man and nature because the development of modern biological technology, but it also cannot avoid produce some new problem which made people have a think deeply to biological warfare, ethics and morals, law, society, food safety, production of industry and agriculture, energy resources, environment.

Agriculture↗

PubMed2002

[Isolation and characterization of a novel transcript of hepatopoietin].

A novel transcript of human HPO (HPO-205) encoding a 205 amino acid ORF corresponding to a translated product of 23 kD different from the previous HPO that lacks the N-terminal 80 amino acids, was isolated from human fetal liver cDNA library by 5'RACE methods. The dose-dependent stimulation of DNA synthesis of HepG2 hepatoma cells by HPO-205 demonstrated its similar biological activity with HPO in vitro. The level of MAPK (mitogen-activated protein kinase)phosphorylation was further examined by Western blot analysis and the result revealed that HPO-205 protein might have stronger activity on stimulating hepatic cell proliferation than that of HPO. The similar result was observed by FACS technique. Therefore, our results suggest that the HPO-205 has activity to stimulate proliferation of liver derived cells, and this activity may be stronger than HPO.

Amino Acid Sequence↗

PubMed1998

Partial isolation and identification of hepatic stimulator substance mRNA extracted from human fetal liver.

AIM:To partially isolate and identify hepatic stimulator substance mRNA from human fetal liver tissues.METHODS:The poly (A)mRNA was extracted from human fetal liver tissues of 4-5 month gestation, fractionated by size on sucrose gradient centrifugation, translated into protein from each fraction in vitro and then its products were tested for HSS activity.RESULTS:Twenty-two 500 total RNA was obtained from human fetal liver tissues and pooled.mRNA of 420 was yielded,processed by oligo(dT)-cellulose column chromatography, then was size-fractionated by ultracentrifution on a continuous sucrose density gradient (5%-25%), and separated into 18 fractions.Translated products of mRNA in fraction 8 and 9 could produce a two-fold increase in the incorporation of( 3)H-TdR into DNA of SMMC-7721 hepatoma cells and in a heat resistant and organ-specific way.CONCLUSION:The partially purified HSS mRNA was obtained and this would facilitate the cloning of HSS using expression vectors.

Journal Article↗

PubMed1997

Expression and Activity of Recombinant Human Augmenter of Liver Regeneration.

The cDNA of human augmenter of liver regeneration was subcloned onto the downstream of the P(R)P(L) promoter of the expression plasmid pBV220. The recombinant plasmid could stably express ALR with high efficiency (up to 20% of the total bacterial proteins) in E. coli through thermal induction. The expressed recombinant ALRs could produce a significant increase in the incorporation of (3)H-TdR into liver DNA of a 1/3 hepatectomized test animal and also had a potent antihepatitis effect. These results suggest that ALR appears to be an important regulator of liver regeneration and may be used in clinical trial for enhancing liver regeneration in the treatment of hepatic diseases.

Journal Article↗