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Biomedical subjects

Wei Gao

Publications and source records attributed to Wei Gao.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Prediction of 2-year outcome by combining TIMI myocardial perfusion grading with sum ST segment resolution in patients with acute myocardial infarction].

OBJECTIVE: To evaluate the value of combining TIMI myocardial perfusion (TMP) grading with sum ST segment resolution (sumSTR) in prediction of the 2-year outcome and heart function in patients with acute myocardial infarction (AMI) after emergency percutaneous intervention (PCI). METHODS: Seventy-seven consecutive patients of AMI with elevated ST segment, 62 males and 15 females, aged 63 +/- 12 (30-91), underwent PCI. TMP grading was used in combination of electrocardiography to calculate the sumSTR so as to evaluate the effect of myocardial reperfusion. The patients with TMP grade 2-3 and sumSTR > or = 30% were included in the group of better perfusion, and those with the TMP grade 0-1 and sumSTR < 30% were included in the group of lower perfusion. The cardiac events, including death, reinfarction, revascularization, angina pectoris, and heart failure were recorded. The left ventricular end-diastolic dimension (LVEDD) and left ventricular ejection fraction (LVEF) were measured by echocardiography 72 hours and 2 years after the PCI. RESULTS: There were 37 patients in the lower perfusion group and 39 patients in the better perfusion group. Cos regression showed that TMP grade 0-1 associated with sumSTR < 30% was an independent factor for 2-year cardiac events (RR = 13.186, 95% CI 2.149 - 80.917, P = 0.005). The LVEDD 2 years after PCI was 60 mm +/- 4 mm, significantly higher than that 72 hours after PCI (53 mm +/- 4 mm. P < 0.01) in the lower perfusion group. The LVEDD increased by 7.1 mm +/- 1.9 mm two years after PCI in the lower perfusion group, significantly more than that in the better perfusion group (1.5 mm +/- 1.2 mm, P < 0.01). The myocardial perfusion after PCI was closely correlated with the extent of heart function improvement 2 years after (chi(2) = 50.58, P < 0.01). CONCLUSION: TMP grading combined with sumSTR helps predict the 2-year outcome and heart function in the patients with AMI after emergency PCI.

Adult↗
PubMed2005

Superior neovascularization and muscle regeneration in ischemic skeletal muscles following VEGF gene transfer by rAAV1 pseudotyped vectors.

Recombinant adeno-associated virus serotype 2 (rAAV2) vector has been widely employed for gene therapy. Recent progress suggests that the new serotypes of AAV showed a better performance than did AAV2 in normal tissues. Here, we evaluate the potential role of human vascular endothelial growth factor (VEGF) gene transfer using rAAV vector pseudotyped with serotype 1 capsid proteins (rAAV1) in the treatment of muscle ischemia. In ischemic skeletal muscles, the rAAV1-LacZ vector allowed higher level, broader distribution, and long-lasting gene expression compared with the rAAV2-LacZ vector. Muscle VEGF165 production following the rAAV1-VEGF165 vector injection was 5-10 times higher than that following the rAAV2-VEGF165 vector injection. VEGF165 production mediated by the rAAV1-VEGF165 vector stimulated a large set of neovascularization with relatively mature vascular structures and enhanced muscle regeneration in the ischemic skeletal muscles. Thus, the rAAV1-VEGF165 vector mediated gene transfer may be a therapeutic approach to peripheral vascular diseases.

Adenoviridae↗
PubMed2005

[Hypoxia/reoxygenation induced endoplasmic reticulum stress in cultured neonatal rat cardiomyocyte].

OBJECTIVE: To investigate the effect of hypoxia/reoxygenation on endoplasmic reticulum stress in cultured neonatal rat cardiomyocytes. METHODS: Neonatal rat cardiac myocytes in primary culture were exposed to hypoxia for 5.5 hours and subsequently reoxygenation for 2-24 hours. Western blot and RT-PCR were applied to monitor the expression change of GRP78 (glucose regulated protein 78). 2-deoxy-D-glucose (2-DG) was the positive control of this study. Then Western blot and RT-PCR were used to examine the expression of GRP78. RESULTS: Cell viability was decreased obviously after hypoxia/reoxygenation. Compared with untreated cells, the GRP78 content of the cells had increased significantly in the hypoxia/reoxygenation cells. The level of GRP78 protein and mRNA elevated from the points of 2 hours to 24 hours after reoxygenation, and increased most obviously at the point of 4 hours after reoxygenation. (4 hours: protein level 142% of the control, mRNA level 200%). 2-DG could induce the increasing expression of GRP78 in a concentration-dependent manner from 10-50 mmol/L. CONCLUSION: Hypoxia/reperfusion can induce endoplasmic reticulum stress in rat cardiomyocytes.

Animals↗
PubMed2005

Structure-based design of potent non-peptide MDM2 inhibitors.

A successful structure-based design of a class of non-peptide small-molecule MDM2 inhibitors targeting the p53-MDM2 protein-protein interaction is reported. The most potent compound 1d binds to MDM2 protein with a Ki value of 86 nM and is 18 times more potent than a natural p53 peptide (residues 16-27). Compound 1d is potent in inhibition of cell growth in LNCaP prostate cancer cells with wild-type p53 and shows only a weak activity in PC-3 prostate cancer cells with a deleted p53. Importantly, 1d has a minimal toxicity to normal prostate epithelial cells. Our studies provide a convincing example that structure-based strategy can be employed to design highly potent, non-peptide, cell-permeable, small-molecule inhibitors to target protein-protein interaction, which remains a very challenging area in chemical biology and drug design.

Biomimetic Materials↗
PubMed2005

An attempt to increase the efficiency of protein crystal screening: a simplified screen and experiments.

Macromolecular crystallization remains a bottleneck in structure determination by X-ray diffraction. Based on the data reflecting success rates of crystallization conditions in different screens and the information derived from the BMCD and other related studies, a simplified screen has been designed to increase the success rate of traditional screening and to save samples, time and cost. The screen has been tested with six protein samples which had been crystallized before and its comparison with Crystal Screen (Hampton Research) was also performed with lysozyme crystallization. The experimental results show that for obtaining crystal leads, the success rate of the simplified screen is reasonably higher. In addition, it has been successful in crystallizing two new proteins from snake venom using the simplified screen that had failed with Crystal Screen. These results indicate that the simplified screen, which assembles and optimizes the efficient crystallization conditions from distinct screens, extends the region of crystallization and improves the success rate of screening. Based on information of newly published efficient crystallization conditions, the simplified screen could be developed and optimized continuously in the future.

Animals↗
PubMed2005

A novel site contributing to growth-arrest-specific gene 6 binding to its receptors as revealed by a human monoclonal antibody.

Gas6 (growth-arrest-specific gene 6) is a vitamin K-dependent protein known to activate the Axl family of receptor tyrosine kinases. It is an important regulator of thrombosis and many other biological functions. The C-terminus of Gas6 binds to receptors and consists of two laminin-like globular domains LG1 and LG2. It has been reported that a Ca2+-binding site at the junction of LG1 and LG2 domains and a hydrophobic patch at the LG2 domain are important for receptor binding [Sasaki, Knyazev, Cheburkin, Gohring, Tisi, Ullrich, Timpl and Hohenester (2002) J. Biol. Chem. 277, 44164-44170]. In the present study, we developed a neutralizing human monoclonal antibody, named CNTO300, for Gas6. The antibody was generated by immunization of human IgG-expressing transgenic mice with recombinant human Gas6 protein and the anti-Gas6 IgG sequences were rescued from an unstable hybridoma clone. Binding of Gas6 to its receptors was partially inhibited by the CNTO300 antibody in a dose-dependent manner. To characterize further the interaction between Gas6 and this antibody, the binding kinetics of CNTO300 for recombinant Gas6 were compared with independently expressed LG1 and LG2. The CNTO300 antibody showed comparable binding affinity, yet different dependence on Ca2+, to Gas6 and LG1. No binding to LG2 was detected. In the presence of EDTA, binding of the antibody to Gas6 was disrupted, but no significant effect of EDTA on LG1 binding was evident. Further epitope mapping identified a Gas6 peptide sequence recognized by the CNTO300 antibody. This peptide sequence was found to be located at the LG1 domain distant from the Ca2+-binding site and the hydrophobic patch. Co-interaction of Gas6 with its receptor and CNTO300 antibody was detected by BIAcore analysis, suggesting a second receptor-binding site on the LG1 domain. This hypothesis was further supported by direct binding of Gas6 receptors to an independently expressed LG1 domain. Our results revealed, for the first time, a second binding site for Gas6-receptor interaction.

Amino Acid Sequence↗
PubMed2005

Prevalence of essential tremor in Singapore: a study on three races in an Asian country.

To investigate the prevalence of Essential Tremor (ET) in Singapore and compare the rates between Singaporean Chinese, Malays, and Indians, a community-based survey among a disproportionate random sample of 15,000 individuals (9000 Chinese, 3000 Malays, 3000 Indians) aged 50 years and above was conducted. In phase 1, trained interviewers conducted a door-to-door survey using a screening questionnaire for Parkinson's disease. In phase 2, medical specialists examined participants who screened positive to evaluate for the presence of postural or kinetic tremor of the upper limbs, or head tremor. Participants with suspected ET had their diagnosis confirmed in phase 3 by a movement disorders specialist and fellow based on the latest core diagnostic criteria. Forty participants with classic ET were identified. The prevalence rate (PR) of ET was 2.37 per 1000 (95% CI: 1.65-3.32), age-adjusted to UICC world standard population. The PR was significantly higher in males (p=0.01) and increased significantly with age (p<0.001). Indians (PR=4.94 per 1000, 95% CI: 2.63-9.04) were 1.8 times more likely to have ET than Chinese (PR=2.77 per 1000, 95% CI: 1.78-4.17) (p=0.08). No Malays with ET were identified. The data suggest that the prevalence of ET increases with age, is higher in males and may be higher amongst Indians.

Age Distribution↗
PubMed2005

Albumin activates ERK via EGF receptor in human renal epithelial cells.

Emerging clinical and experimental evidence strongly implicates proteinuria in the progression of kidney disease. One pathway involves the activation of NFkappaB by albumin, and it has been demonstrated that the activation of NFkappaB induced by albumin is dependent on mitogen-activated protein kinase ERK1/ERK2. To study the effect of albumin on gene expression, primary human renal tubular cells were exposed in vitro to albumin (1%) for 6 h, and gene expression profiling was performed with the human oligonucleotide microarray, U133A Affymetrix Gene Chip. In all, 223 genes were differentially regulated by albumin, including marked upregulation of the EGF receptor (EGFR) and IL-8. Accordingly, the authors sought to delineate the signaling pathway linking albumin to the EGFR and activation of ERK1/ERK2. It was found that albumin led to a dose- and time-dependent activation of ERK1/ERK2. Treatment with albumin led to EGFR phosphorylation, but the activation of ERK1/ERK2 was prevented by pretreatment of the cells with AG-1478, the EGFR kinase inhibitor, at a dose that inhibited EGF-induced ERK1/ERK2 activation. Exogenously administered reactive oxygen species (ROS) were found to activate ERK1/ERK2 via the EGFR and src tyrosine kinase activity and pretreatment of cells with the antioxidant N-acetylcysteine (NAC) and the NADPH oxidase inhibitor DPI abrogated albumin-induced activation of ERK1/ERK2. The src tyrosine kinase inhibitor, PP2, also inhibited the albumin-induced activation of ERK1/ERK2. Finally, pretreatment with AG-1478, the MEK inhibitor UO126, and NAC prevented the albumin-induced increase in IL-8 expression. The authors conclude that the EGF receptor plays a central role in the signaling pathway that links albumin to the activation of ERK1/ERK2 and increased expression of IL-8. Gene profiling studies suggest that there may be a positive feedback loop through the EGFR that amplifies the response of the proximal tubule cell to albumin. Taken together, these results suggest that the EGFR may be an important treatment target for kidney disease associated with proteinuria.

Albumins↗
PubMed2005

Nonenzymatic glucose detection by using a three-dimensionally ordered, macroporous platinum template.

A three-dimensionally ordered, macroporous, inverse-opal platinum film was synthesized electrochemically by the inverted colloidal-crystal template technique. The inverse-opal film that contains platinum nanoparticles showed improved electrocatalytic activity toward glucose oxidation with respect to the directly deposited platinum; this improvement is due to the interconnected porous structure and the greatly enhanced effective surface area. In addition, the inverse-opal Pt-film electrode responds more sensitively to glucose than to common interfering species of ascorbic acid, uric acid, and p-acetamidophenol due to their different electrochemical reaction mechanisms. Results showed that the ordered macroporous materials with enhanced selectivity and sensitivity are promising for fabrication of nonenzymatic glucose biosensors.

Electrodes↗
PubMed2005

Lithospheric structure of the Rio Grande rift.

A high-resolution, regional passive seismic experiment in the Rio Grande rift region of the southwestern United States has produced new images of upper-mantle velocity structure and crust-mantle topography. Synthesizing these results with geochemical and other geophysical evidence reveals highly symmetric lower-crustal and upper-mantle lithosphere extensional deformation, suggesting a pure-shear rifting mechanism for the Rio Grande rift. Extension in the lower crust is distributed over a region four times the width of the rift's surface expression. Here we propose that the laterally distributed, pure shear extension is a combined effect of low strain rate and a regionally elevated geotherm, possibly abetted by pre-existing lithospheric structures, at the time of rift initiation. Distributed extension in the lower crust and mantle has induced less concentrated vertical mantle upwelling and less vigorous small-scale convection than would have arisen from more localized deformation. This lack of highly focused mantle upwelling may explain a deficit of rift-related volcanics in the Rio Grande rift compared to other major rift systems such as the Kenya rift.

Journal Article↗
PubMed2005

Isolation and preliminary crystallographic studies of two new phospholipases A2 from Vipera nikolskii venom.

Snake-venom phospholipases A2 (PLA2s) represent a good model for studies of structure-function relationships, mainly because of their small size and diverse pharmacological and toxicological activities. To obtain new members of the abundant PLA2 family, the venom of the viper Vipera nikolskii was fractionated for the first time and two new proteins, VN5-3 and VN4-3, were isolated. Both proteins show phospholipase A2 activity and may possess neurotoxic activity. Based on the determined partial amino-acid sequences, the new proteins can be classified as basic Asp49 phospholipases A2. They were crystallized using the hanging-drop vapour-diffusion method and crystals of both proteins belong to space group R32, with similar unit-cell parameters: a = b = 76.29, c = 303.35 A for protein VN5-3 and a = b = 76.28, c = 304.39 A for protein VN4-3. Diffraction data sets to 3.0 and 2.2 A resolution were collected and processed for the VN5-3 and VN4-3 crystals, respectively. Preliminary analysis indicates that there are two molecules in the asymmetric unit for both crystals. Further crystallographic studies will help in understanding the structural basis for the multiple functions of snake-venom PLA2s.

Animals↗
PubMed2005

[Criteria suitable for diagnosis of acute respiratory distress syndrome/multiple organ dysfunction syndrome at moderately high altitude area].

OBJECTIVE: To compare the diagnostic parameters of acute respiratory distress syndrome/multiple organ dysfunction syndrome (ARDS/MODS) at high altitude (H-ARDS/MODS) with that on plain, and to establish a more practical diagnostic criterion of H-ARDS/MODS. METHODS: Five hundred and five cases fulfilled the criteria for the diagnosis of ARDS/MODS were divided into three groups according to the altitude of their habitation: control group including inhabitants (<430 m) on plain (CG, n=113), moderate high altitude group 1 inhabitants at the altitude of 1,517 m (H1G, n=314), moderate high altitude group 2 inhabitants at the altitude of 2,261 m to 2,400 m (H2G, n=78). The ARDS/MODS scores of the three groups were made according to the diagnostic criteria of Lushan conference, Marshall(1995) and Lanzhou criteria drafted by the authors respectively to set up three data analyzing models, followed by plotting of receiver operating characteristic curves (ROC curve) and calculation of the Yordon Index and the optimum cutoff points of the parameters,in order to study the accuracy of the three diagnostic criteria in predicting the outcome of the patients suffering from ARDS/MODS. RESULTS: In CG group, the differences were not significant in area of ROC, the maximal Yordon Index, the optimum cutoff points and the sensitivity and the specificity for three criteria; but the differences were significant for the three criteria in H1G group. Further investigation in comparing the ROC values of lung, brain, heart and kidney, the Lanzhou criteria were more advantageous in the high altitude than the other criteria. CONCLUSION: (1)The current diagnostic criteria of ARDS/MODS are not suitable for the diagnosis of these syndromes in moderately high or high altitude areas. It is necessary to revise the diagnostic criteria of H-ARDS/MODS. (2)One thousand five hundred and seventeen meters in altitude might be considered to be an important borderline, above with the diagnostic criteria of ARDS/MODS for patients inhabiting on plain could not be suitably applied to those living above this level.

Altitude↗
PubMed2005

[Magnetic resonance imaging diagnosis of occupied lesions in cerebellopontine angle area:a report of 78 cases].

BACKGROUND & OBJECTIVE: It is difficult to diagnose cerebellopontine angle area tumor because of many sorts and origins of the tumor. This study was to explore magnetic resonance imaging (MRI) diagnosis of occupied lesions in cerebellopontine angle area. METHODS: MRI records of 78 patients with pathologically confirmed occupied lesions in cerebellopontine angle area were analyzed. RESULTS: Of the 78 cases, 48 (61.5%) were unilateral acoustic neuroma, 5(6.4%) were bilateral acoustic neuroma, 12 (15.4%) were meningioma, 4 (5.1%) were trigeminal neuroma, 3 (3.8%) were hemangioblastoma, 3 (3.8%) were lipoma, 2 (2.6%) were melanoma, 1 (1.3%) was medulloblastoma. According to the anatomic site, tumor lesion character, and MRI signal character, the majority of cerebellopontine angle area tumors were diagnosed accurately. CONCLUSION: MRI plays an important role in diagnosis of occupied lesions in cerebellopontine angle area.

Adolescent↗
PubMed2005

[Foraging habitat selection of Otis tarda dybowskil during its breeding season].

From April to July of 2000 and 2001, the authors studied the foraging habitat selection of Otis tarda dybowskil in the southeast Keerqin of Inner Mongolia by sampling method. The results showed that whether at burned or at non-burned grassland, the foraging habitat of Otis tarda dybowski had the same feature in vegetation structure, the plant height was about 13 cm on average, with the highest of 30 cm, and there were abundant species of plants and insects with big density that the bird favored to eat. The bird more concerned with the abundance of plants at burned grassland, while that of insects at non-burned grassland.

Animals↗
PubMed2005

[Multiple organ dysfunction scoring system: comparison and evaluation of correlation and accuracy of the three scoring systems in predicting the outcome of multiple organ dysfunction syndrome on highland].

OBJECTIVE: To study the characteristics of the diagnostic parameters of acute respiratory distress syndrome/multiple organ dysfunction syndrome on plateau (H-ARDS/MODS) and compare the accuracy of the three MODS scoring criteria in predicting the outcome of syndrome. METHODS: Five hundred and forty cases fulfilling the criteria of MODS were divided into four groups according to the altitude of their inhabitation area: control group (on plain, CG, n=113, altitude: <430 m), moderate high altitude group 1 (H1G, n=314, altitude: 1,517 m), moderate high altitude group 2 (H2G, n=78, altitude: 2,261 m to 2,400 m) and high altitude group (HG, n=35, altitude: 2 808 m to 3 400 m). According to the diagnostic criteria of Lushan conference and Marshall (1995) commonly used on plain, and Lanzhou criteria drafted by the authors, three data analyzing models were set up to draw the receiver operating characteristic (ROC) curves, the Yordon Index and the optimum cutoff points of the parameters were calculated and the accuracy of the three respective diagnostic criteria was evaluated in predicting the outcome of ARDS/MODS. Multiple factors affecting the outcome of MODS were analyzed using the method of stepwise forward regress model. RESULTS: Following the increase in altitude, Lanzhou criteria was clearly superior to the other two criteria in the area of ROC, the sensitivity, the specificity, and also for the optimum cutoff points of MODS. Multi-variable regression analysis showed that the impacting factor of Lanzhou criteria was the highest (P<0.05). CONCLUSION: (1)Some parameters of the current diagnostic criteria of ARDS/MODS are not suitable in moderately high or high altitude areas. It is necessary to set up the diagnostic criteria of H-ARDS/MODS. (2)Some clinical characteristics might change in areas 1,500 m altitude or higher. The pathophysiological mechanism might be attributable to peculiar biologic reactions due to hypoxia stress reaction, and it is worth further study.

Altitude↗
PubMed2005

[Therapeutic effect of Qingkailing and methylprednisolone injection alone or combined on the acute lung injury induced by oleic acid in rabbits].

OBJECTIVE: To investigate the effect of Qingkailing and Methylprednisolone (MP) injection alone or combined on the acute lung injury (ALI) induced by oleic acid in rabbits. METHOD: The rabbits were randomly divided into 11 groups: oleic acid group; control group; treatment groups including low, middle and high dosage groups of Qingkailing and MP alone and combined, respectively. ALI model was established by i.v. oleic acid (0.05 mL x kg(-1)) in these groups, and then i.v. above drugs respectively, while in control group, the same volume of normal saline was given. The respiratory amplitude and rate were observed, and blood samples were taken from cervical artery for blood-gas analysis before and at 30, 60, 120 min after oleic acid or normal saline administration. At the end of experiment, the concentration of LDH, CAT and MDA in the lung tissue were measured and pathologic changes of lung tissue were observed microscopically. RESULT: Compared with oleic acid group, the respiratory amplitude markedly enhanced (P < 0.05) and respiratory rate lowered (P < 0.05) in the low, middle and high dose groups of Qingkailing and MP injection. On the 30 min of treatment, PaO2 increased significantly (P < 0.05) in the low and middle dose groups of combined Qingkailing and MP injection; PaCO2 decreased markedly (P < 0.05) on the 120 min of treatment in each treatment group. The level of LDH significantly increased (P < 0.05), CAT and MDA decreased (P < 0.05) in the middle and high groups of Qingkailing and MP injection. The low and middle dose groups of combined Qingkailing and MP injection can alleviate the pathological changes induced by oleic acid. CONCLUSION: The curative effect of the low dose group of combined Qingkailing and MP for the ALI induced by oleic acid was better than Qingkailing and MP alone, while the big dose groups of Qingkailing and MP alone better than the combination at the same dosage.

Animals↗
PubMed2005

[Therapeutic effect of qingkailing and shengmai injection alone or combined on the acute lung injury induced by oleic acid in rabbits].

OBJECTIVE: To investigate the effect of Qingikailing and Shengmai injection alone or combined on the acute lung injury (AL) induced by oleic acid in rabbits. METHOD: The rabbits were randomly divided into 11 groups: oleic acid group; control group; treatment groups including low, middle and high dosage groups of Qingkailing and Shengmai injection alone and combined, respectively. ALI model was established by iv oleic acid (0.05 mL x kg(-1)) in these groups, and then iv above drugs respectively,while in control group, the same volume of normal saline was given. The respiratory amplitude and rate were observed, and blood samples were taken from cervical artery for blood-gas analysis before and at 30, 60, 120 min after oleic acid or normal saline administration. At the end of experiment, the concentration of LDH, CAT and MDA in the lung tissue were measured and pathologic changes of lung tissue were observed microscopically. RESULT: Compared with oleic acid group, the respiratory amplitude markedly enhanced (P < 0.05) in the low and high dose groups of Qingkailing and Shengmai injection. PaO2 increased significantly (P < 0.05) in the low dose group of combined Qingkailing and Shengmai injection, PaCO2 decreased markedly (P < 0.05) in the low dose groups of Qingkailing and Shengmai injection alone and combined. The level of MDA significantly decreased (P < 0.05) in the each group of Qingkailing and Shengmai injection alone, the level of MDA significantly decreased (P < 0.05) and CAT increased (P < 0.05) in the low dose group of combined Qingkailing with Shengmai injection. The low dose group of combined Qingkailing and Shengmai injection can alleviate the pathological changes induced by oleic acid. CONCLUSION: The curative effect of the low dose group of combined Qingkailing with Shengmai injection for the ALI induced by oleic acid was better than Qingkailing and Shengmai injection alone at the same dosage.

Animals↗