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Biomedical subjects

Ping Wang

Publications and source records attributed to Ping Wang.

At least 253 records · Page 14Linked to original sources
PubMed2004

Legg-Calve-Perthes disease and thrombophilia.

BACKGROUND: Thrombophilia has previously been identified as a potential etiologic factor in Legg-Calve-Perthes disease. We prospectively studied the association between Legg-Calve-Perthes disease and coagulation abnormalities by comparing seventy-two children who had the disease with 197 healthy controls. METHODS: A nonselected, consecutive series of seventy-two patients with Legg-Calve-Perthes disease (mean age [and standard deviation], 6.6 +/- 2.6 years) was studied in their order of referral and compared with 197 healthy controls (mean age, 7.6 +/- 5.1 years). Assays were done for factor-V Leiden, prothrombin G20210A, methylenetetrahydrofolate reductase C677T, and plasminogen activator inhibitor-1 4G/5G gene mutations. Levels of anticardiolipin antibodies immunoglobulin G and M (IgG and IgM), homocysteine, protein C, protein S, antithrombin III, and plasminogen activator inhibitor-1 were also measured. RESULTS: The factor-V Leiden mutation was more common in the patients (eight of seventy-two) than in the controls (seven of 197) (chi-square = 5.7, p = 0.017). After we controlled for the false-discovery rate, the case-control difference remained significant (p = 0.017). The odds ratio for the development of Legg-Calve-Perthes disease in the presence of the factor-V Leiden mutation was 3.39 with a 95% confidence interval of 1.18 to 9.73. A high level of anticardiolipin antibodies (IgG and/or IgM) was found in nineteen of the seventy-two patients compared with twenty-two of the 197 controls (chi-square = 9.5, p = 0.002). After we controlled for the false-discovery rate, the case-control difference remained significant (p = 0.002). The odds ratio of patients with Legg-Calve-Perthes disease having one or more abnormalities in factor V, anticardiolipin antibody IgG, or anticardiolipin antibody IgM as opposed to normal values for all three variables was 3.29 (95% confidence interval, 1.73 to 6.24; p = 0.0003). CONCLUSIONS: Two thrombophilic risk factors, the factor-V Leiden mutation and anticardiolipin antibodies, are associated with Legg-Calve-Perthes disease, an association that may reflect causality. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Adolescent↗
PubMed2004

[Experimental and clinical research on the effect of keyouling on condyloma acuminatum and adjustment of cellular immunity function].

OBJECTIVE: To discuss the mechanism of the traditional Chinese medicine Keyouling oral liquid in the treatment of condyloma acuminatum(CA) and the adjustment of cellular immunity function. METHODS: The IL-18 and TNF-alpha levels of peripheral serum and wart tissue of patterned rats and CA patients exposed to Keyouling were determined by means of double-antibody sandwich ELISA, and the NK cellular activity of the spleen of the patterned rats and that of the peripheral blood of the CA patients exposed to Keyouling were determined by means of 3H-TdR isotype release. RESULTS: The IL-18 and TNF-alpha levels, the NK cellular activity of the high-dosage group showed significant difference from those of the pattern group and low-dosage group in animal experiment(P < 0.05); the IL-18 and TNF-alpha levels of peripheral serum and wart tissues, and the NK cellular activity of the peripheral blood of the treatment group showed significant difference from those of the control group after treatment(P < 0.01, P < 0.05). CONCLUSIONS: Keyouling oral liquid has significant positive adjusting effect, which can markedly ameliorate the cellular immunadeficiency of the patterned animals and reinforce the cellular immunocompetence of CA patients.

Adolescent↗
PubMed2004

[Effects of leukemia bone marrow stromal cells on resistance of co-cultured HL-60 to idarubicin].

To study the role of hematopoietic microenvironment abnormality in development of minimal residual disease and its mechanism, the viability of HL-60 cells was investigated by means of bone marrow stromal cell culture system or co-culture system of bone marrow stromal cell with HL-60 cells and idarubicin (IDA), flow cytometry and ELISA. The results showed that viability of HL-60 cells gradually decreased along with the increase of IDA dose and prolongation of culture time. Amount of HL-60 cells co-cultured with leukemia bone marrow stramal cells was significantly increased as compared with that of the control (P < 0.05). Bone marrow stromal cells or stromal cell conditioned medium reduced the effect of IDA on HL-60 cells in culture. In conclusion, leukemia bone marrow stromal cells contribute to increasing resistance of HL-60 cells to chemotherapeutic agents, and play some role in developing minimal residual disease.

Bone Marrow Cells↗
PubMed2004

[Preparation and characterization of anti-human IL-15 monoclonal antibody].

AIM: To prepare monoclonal antibody (mAb) against human interleukin-15 (hIL-15) and identify its characterization. METHODS: The GST-IL-15 was extracted from the gene-engineering bacteria E. coli and identified by SDS-PAGE. The gel strip containing GST-IL-15 was cut off to immunize BALB/c mice. The splenocytes of immunized mice were fused with Sp2/0 myeloma cells by a routine method and the hybridomas were selected in HAT medium. The hybridoma cells secreting specific antibody were detected by ELISA and cloned by limiting dilution. The stability of the obtained hybridoma cells and the specificity of anti-hIL-15 mAb the hybridoma cells secreted were identified. In addition, the New Zealand rabbits were immunized with the rhIL-15 inclusion body protein (rhIL-15IBP) to prepare the polyclonal antibody (pAb) against hIL-15. A sandwich ELISA was established with the anti-IL-15 mAb and pAb as coating and sandwich antibodies, respectively, to detect hIL-15. RESULTS: One hybridoma cell line which could stably secrete specific mAb was obtained. A sandwich ELISA for detecting rhIL-15 protein was established and its sensitivity was as low as 10 microg/L. CONCLUSION: The anti-hIL-15 mAb was prepared successfully. A sandwich ELISA for the detection of hIL-15 was established.

Animals↗
PubMed2004

[Immunogenicity of a multiple epitope DNA vaccine against hepatitis B virus].

AIM: To study the immunogenicity of a multiple epitope DNA vaccine against hepatitis B virus(HBV). METHODS: A multiple epitope HBV antigen gene BPT was synthesized and cloned into eukaryotic expression vector pcDNA3.1 and then BALB/c mice were immunized with the DNA vaccine. The specific humoral and cellular immune responses were detected by indirect ELISA, cytotoxicity of CTL, and lymphocyte proliferation. The immunized mice were also observed for the possible toxicity and side effects after administration of the DNA vaccine. RESULTS: Immunization with pcDNA3.1/BPT elicited high-level antigen-specific IgG and antigen-specific CTL response, and stimulated lymphocyte proliferation. RT-PCR analysis of spleen lymphocytes showed that levels of IL-12 mRNA in immunized mice were notably higher than that in control mice. CONCLUSION: The multiple epitope HBV DNA vaccine can induce specific humoral and cellular immune responses, which lays a certain foundation for development of prophylactic and therapeutic HBV vaccine.

Animals↗
PubMed2004

[Sodium butyrate induces rat hepatic oval cells differentiating into mature hepatocytes in vitro].

OBJECTIVE: To elucidate the effects of sodium butyrate on rat hepatic oval cell differentiation in vitro. METHODS: Hepatic oval cells were isolated from rats fed with a choline-deficient diet supplemented with 0.1% (w/w) ethonine for 4 to 6 weeks. The cultured hepatic oval cells were identified by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). After hepatic oval cells were treated with sodium butyrate, the morphological changes were studied through Giemsa staining and the albumin expression level was tested by Western blot. RESULTS: Immunohistochemical results showed the isolated cells were positive for both mature hepatocyte marker albumin and bile duct cell marker cytokeratin-19. Furthermore, RT-PCR results showed that the cells expressed stem cell marker c-kit, but not hematopoietic stem cell marker CD34. In short, the isolated cells were rat hepatic oval cells. 0.75 mmol/L sodium butyrate induced obvious phenotype changes of hepatic oval cells, including enlargement of the oval cells, a decrease in nucleus to cytoplasm ratio, and a 50% increase in the number of binucleated cells. Western blot results showed that 0.75 mmol/L sodium butyrate markedly raised the expression of albumin. CONCLUSION: Sodium butyrate, a differentiation promoting agent, can induce rat hepatic oval cells (liver progenitor cells) to differentiate into mature hepatocytes in vitro.

Animals↗
PubMed2004

[Studies of somatic embryogenesis and genetic transformation by Agrobacterium- mediated in soybean].

Somatic embryogenesis was induced and the regenerated plants were obtained by higher concentrations of auxins with immature cotyledon of 55 genotypes in soybean. Bivalent insect resistant genes were transformed into immature cotyledon of soybean which have high frequency of somatic embryogenesis via Agrobacterium-mediated. The results showed that 14 genotypes possessed high frequency of somatic embryogenesis (more than 40%) among soybean genotypes from Northeast area. 2147 immature cotyledons of 5 different soybean genotypes cultured in Northeast area were inoculated with LBA4404 (including pGBI121S4ABC plasmid). 17 plantlets were obtained under Kanamicy selection. 12 plantlets showed positive reaction in PCTR and PCR-Southern detection. These analyses confirmed the presence of introduced Bt gene in soybean.

Cotyledon↗
PubMed2004

[Research progress on system of transgene in soybean].

This review introduced the recent research progress on transgenic methods and system of receptor in soybean. The major obstacles of genetic transformation in soybean and possible approach for solving the problem were also discussed. Cotyledon node via Agrobacterium tumefaciens-mediated and immature cotyledon via particle bombardment were thought to be the efficient systems of genetic transformation. Three problems existed in genetic transformation of soybean. The first one was that the system of tissue culture needs to be further improved. The second was that efficiency of genetic transformation was still low and difficult to be repeated. The last one was that restricted genotypes of soybean have been transformed successfully as a receptor. The path of solving these problems need to set a new and high efficient system for tissue culture in soybean. Also the number of target gene to be transformed will be increased from single gene to several genes at same time.

Agrobacterium tumefaciens↗
PubMed2004

[Isolation and prelimary characterization of a kind of rat liver potential progenitor cells small round hepatic cells].

Liver undergoes profound regeneration usually after hepatic damage. It has been shown in recent study that two kinds of liver stem cells, which are mainly oval cells (OVCs) and small hepatocytes, are involved in the process of liver regeneration as they differentiated into premature liver cells. However, the origination of oval cells as well as its differentiation property is not quite understood. In this study, we isolated a novel potential liver progenitor cells, namely small round cells (SRCs). The cellular features of the cells such as morphological appearance, surface marker, growth curve, and differentiation induced by DMSO were analyzed. SRCs and OVCs were obtained by using discontinuous digestions and isopyknic centrifugation, respectively. With non-radioactive measurement of MTT, the cell growth was assayed. Meanwhile, SRCs were stained with antibodies against CK19, ALB and AFP antibody to characterize their tissue-specificities. The results showed that SRCs appeared in round-shaped, but irregular in size. The nuclei of SRCs were relative small with rich nucleolus visible. SRCs were semi-floated during primary culture. Even cultured in F12:DMEM (1:1) mixed-medium supplemented with 15% fetal calf serum, viability of the cells could merely be expanded over 7 days. SRCs were positively stained by CK19, ALB and AFP within initial 3 days. After DMSO stimulation, SRCs were not only morphologically changed into OVCs, but also expressed those markers identical to OVCs. It was suggested that SRCs could be considered as an potential candidate of liver progenitors which were related to OVCs.

Animals↗
PubMed2004

[Myocardial ultrastructural changes in rats following different levels of acute +Gz exposure].

OBJECTIVE: To observe the effects of different levels of acute +Gz exposure on myocardial ultrastructure of rats and provide experimental basis for further development of anti-G measures. METHOD: Twenty male Wistar rats were randomly divided into 4 groups (n=5): normal control group, +20 Gz group, +10 Gz group and +5 Gz group. Profile of the centrifuge +Gz exposure was trapezoidal, in which +20 Gz lasted for 30 s, +10 Gz for 1.5 min. +5 Gz exposure was repeated for 3 times with 30 min interval and each for 1.5 min. Myocardial tissue of left ventricle was sampled for transmission electron microscopy 5 h after exposure. RESULT: +20 Gz and +10 Gz exposure caused obvious edema of myocardial and endothelial cells, myofibril disorder and injuries of mitochondria and nucleus. Breaks of myocardial fiber, formation of contraction bands and rupture of mitochondria were also observed in +20 Gz group. In +5 Gz group, there was still slight edema of myocardial and endothelial cells, while organic changes of myocardial ultrastructure were not observed. CONCLUSION: High +Gz exposure can cause myocardial ultrastructural injury in rats. Slight reversible injured response can also be observed in myocardial cell after repeated moderate level of +Gz exposure. This indicates that attention should be paid to the study of the effect of high +Gz on heart in pilots.

Acceleration↗
PubMed2003

Catalytic behaviors of enzymes attached to nanoparticles: the effect of particle mobility.

Nanoparticles provide an ideal remedy to the usually contradictory issues encountered in the optimization of immobilized enzymes: minimum diffusional limitation, maximum surface area per unit mass, and high effective enzyme loading. In addition to the promising performance features, the unique solution behaviors of the nanoparticles also point to a transitional region between the heterogeneous (with immobilized enzymes) and homogeneous (with soluble free enzymes) catalysis. The particle mobility, which is related to particle size and solution viscosity through Stokes-Einstein equation, may impact the reaction kinetics according to the collision theory. The mobility-activity relationship was examined through experimental studies and theoretical modeling in the present work. Polystyrene particles with diameters ranging from 110-1000 nm were prepared. A model enzyme, alpha-chymotrypsin, was covalently attached to the nanoparticles up to 6.6 wt%. The collision theory model was found feasible in correlating the catalytic activities of particles to particle size and solution viscosity. Changes in the size of particles and the viscosity of reaction media, which all affect the mobility of the enzyme catalyst, evidently altered the intrinsic activity of the particle-attached enzyme. Compared to K(M), k(cat) appeared to be less sensitive to particle size and viscosity.

Calcium Carbonate↗
PubMed2003

X-ray structures of two xanthine inhibitors bound to PEPCK and N-3 modifications of substituted 1,8-dibenzylxanthines.

The analysis of the X-ray structures of two xanthine inhibitors bound to PEPCK and a comparison to the X-ray structure of GTP bound to PEPCK are reported. The SAR at N-1, N-7 and developing SAR at C-8 are consistent with information gained from the X-ray structures of compounds 1 and 2 bound to PEPCK. Representative N-3 modifications of compound 2 that led to the discovery of 3-cyclopropylmethyl and its carboxy analogue as optimal N-3 groups are presented.

Crystallography, X-Ray↗
PubMed2003

Modified 3-alkyl-1,8-dibenzylxanthines as GTP-competitive inhibitors of phosphoenolpyruvate carboxykinase.

The first non-substrate like inhibitors of human cytosolic phosphoenolpyruvate carboxykinase (PEPCK) competitive with GTP are reported. An effort to discover orally active compounds that improve glucose homeostasis in Type 2 diabetics by reversibly inhibiting PEPCK led to the discovery of 1-allyl-3-butyl-8-methylxanthine (5). We now report modifications at N-1 and C-8 that improved the in vitro activity of the initial xanthine HTS hit by 100-fold and a developing SAR for this class of inhibitor.

Diabetes Mellitus, Type 2↗
PubMed2003

Neuropilin-1-mediated vascular permeability factor/vascular endothelial growth factor-dependent endothelial cell migration.

Neuropilin-1 (NRP-1) has been found to be expressed by endothelial cells and tumor cells as an isoform-specific receptor for vascular permeability factor/vascular endothelial growth factor (VEGF). Previous studies were mainly focused on the extracellular domain of NRP-1 that can bind to VEGF165 and, thus, enables NRP-1 to act as a co-receptor for VEGF165, which enhances its binding to VEGFR-2 and its bioactivity. However, the exact functional roles and related signaling mechanisms of NRP-1 in angiogenesis are not well understood. In this study we constructed a chimeric receptor, EGNP-1, by fusing the extracellular domain of epidermal growth factor receptor to the transmembrane and intracellular domains of NRP-1 and transduced it into HUVECs with a retroviral expression vector. We observed that NRP-1/EGNP-1 mediates ligand-stimulated migration of human umbilical vein endothelial cells (HUVECs) but not proliferation. Our results show that NRP-1 alone can mediate HUVEC migration through its intracellular domain, and its C-terminal three amino acids (SEA-COOH) are essential for the process. We demonstrate that phosphatidylinositol 3-kinase inhibitor Ly294002 and the p85 dominant negative mutant can block NRP-1-mediated HUVEC migration. NRP-1-mediated migration can be significantly reduced by overexpression of the dominant negative mutant of RhoA (RhoA-19N). In addition, Gq family proteins and Gbetagamma subunits are also required for NRP-1-mediated HUVEC migration. These results show for the first time that NRP-1 can independently promote cell signaling in endothelial cells and also demonstrate the importance of last three amino acids of NRP-1 for its function.

Base Sequence↗
PubMed2003

[The correlation between the electroencephalogram findings and clinical manifestations of Creutzfeldt-Jakob disease].

OBJECTIVE: To investigate the correlation between the EEG findings and the clinical signs of Creutzfeldt-Jakob disease (CJD). METHODS: Serial standard recording during different stage of disease was conducted among 13 patients with CJD, 10 males and 3 females, with the year of onset of 58.2 (49 approximately 65). The EEG findings were analyzed in combination of the clinical symptoms and signs. RESULTS: 12 of the 13 patients showed typical periodic sharp wave complexes (PSWCs), occurring after the onset of myoclonus and akinetic mutism in 8 patients, both after myoconus and before akinetic mutism in 2 cases, and just at the onset of akinetic mutism before or after the onset of myoclonus respectively in 2 cases. Different EEG features were observed in different stages of disease. Frontal intermittent rhythmic delta activity (FIRDA) and frontal intermittent rhythmic triphasic slow wave, which was replaced by PSWC later, were seen in 4 cases. CONCLUSION: PSWC has a close association with myoclonus and akinetic mutism. The best time of EEG recording is when myoclonus and/or akinetic mutism happen. FIRDA and frontal intermittent rhythmic triphasic slow wave may be hint of the onset of PSWC.

Aged↗
PubMed2003

Mutations in the effector binding loops in the C2A and C2B domains of synaptotagmin I disrupt exocytosis in a nonadditive manner.

The secretory vesicle protein synaptotagmin I (syt) plays a critical role in Ca2+-triggered exocytosis. Its cytoplasmic domain is composed of tandem C2 domains, C2A and C2B; each C2 domain binds Ca2+. Upon binding Ca2+, positively charged residues within the Ca2+-binding loops are thought to interact with negatively charged phospholipids in the target membrane to mediate docking of the cytoplasmic domain of syt onto lipid bilayers. The C2 domains of syt also interact with syntaxin and SNAP-25, two components of a conserved membrane fusion complex. Here, we have neutralized single positively charged residues at the membrane-binding interface of C2A (R233Q) and C2B (K366Q). Either of these mutations shifted the Ca2+ requirements for syt-liposome interactions from approximately 20 to approximately 40 microm Ca2+. Kinetic analysis revealed that the reduction in Ca2+-sensing activity was associated with a decrease in affinity for membranes. These mutations did not affect sytsyntaxin interactions but resulted in an approximately 50% loss in SNAP-25 binding activity, suggesting that these residues lie at an interface between membranes and SNAP-25. Expression of full-length versions of syt that harbored these mutations reduced the rate of exocytosis in PC12 cells. In both biochemical and functional assays, effects of the R233Q and K366Q mutations were not additive, indicating that mutations in one domain affect the activity of the adjacent domain. These findings indicate that the tandem C2 domains of syt cooperate with one another to trigger release via loop-mediated electrostatic interactions with effector molecules.

Animals↗