Biomedical subjects
Publications and source records attributed to Wei Deng.
[reaction: see text] Under the Lewis acid catalysis offered by TiCl(3), SnCl(2) can efficiently mediate the aqueous Barbier reactions between aldehydes and allyl chloride or bromide.
In order to investigate the changes of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) expression in residual hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE), the expression levels of VEGF and bFGF expression in specimens surgically removed from 48 HCC patients were detected by immunohistochemical methods, and staining intensity of VEGF and bFGF was assessed by a computer-assisted image-analyzer. Among the 48 patients, 25 underwent partial hepatectomy alone (single operating group), and 23 were subjected to second stage surgical resection after TACE (TACE group). The results showed that the average absorbance value (A) of VEGF was higher in TACE group than that in single operating group (0.152 +/- 0.021 vs 0.131 +/- 0.012, P < 0.01). The Average A of bF-GF in TACE group was 0.127 +/- 0.023, higher than in single operating group (0.111 +/- 0.016, P < 0.05). These results suggested that TACE of HCC can up-regulate the expression of VEGF and bFGF in HCC tissues possibly due to anoxia and ischemia.
OBJECTIVE: To establish a model for one choosing controls with a suitable concentration for internal quality control (IQC) with qualitative ELISA detection, and a consecutive plotting method on Levey-Jennings control chart when reagent kit lot is changed. METHODS: First, a series of control serum with 0.2, 0.5, 1.0, 2.0 and 5.0ng/ml HBsAg respectively were assessed for within-run and between-run precision according to NCCLs EP5 document. Then, a linear regression equation (y=bx + a) with best correlation coefficient (r > 0.99) was established based on S/CO values of the series of control serum. Finally, one could choose controls with S/CO value calculated from the equation (y = bx + a) minus the product of the S/CO value multiplying three-fold between-run CV to be still more than 1.0 for IQC use. For consecutive plotting on Levey-Jennings control chart when ELISA kit lot was changed, the new lot kits were used to detect the same series of HBsAg control serum as above. Then, a new linear regression equation (y2 = b2x2 + a2) with best correlation coefficient was obtained. The old one (y1 =b1x1 + a1) could be obtained based on the mean values from above precision assessment. The S/CO value of a control serum detected by new lot kit could be changed to that detected by old kit lot based on the factor of y2/y1. Therefore, the plotting on primary Levey-Jennings control chart could be continued. RESULTS: The within-run coefficient of variation CV of the ELISA method for control serum with 0.2, 0.5, 1.0, 2.0 and 5.0ng/ml HBsAg were 11.08%, 9.49%, 9.83%, 9.18% and 7.25%, respectively, and between-run CV were 13.25%, 14.03%, 15.11%, 13.29% and 9.92%. The linear regression equation with best correlation coefficient from a test at random was y = 3.509x + 0.180. The suitable concentration of control serum for IQC could be 0.5ng/ml or 1.0ng/ml. The linear regression equation from the old lot and other two new lots of the ELISA kits were y1 = 3.550(x1) + 0.226, y2 = 3.238(x2) +0.388, and y3 =3.428(x3) + 0.148, respectively. Then, the transferring factors of 0.960 (y2/y1) and 0.908 (y3/y1) were obtained. CONCLUSION: The results shows that the model established for IQC control serum concentration selecting and for consecutive plotting on control chart when the reagent lot is changed is effective and practical.
Ecotone is a special zone in the landscape, which is very susceptive to the changes in environmental conditions, and hence, is prone to the disturbance by unfavorable conditions. Human activity has a series of positive and negative effects on it, and greatly changes the geo-chemical process in the ecosystem. In the ecosystem, especially in the ecotone, different systems and regimes are interconnected and inter-determined. For the sustainable development of ecosystem and the protection and rational utilization of resources, it is of great importance to study this internal relationship and to seek rational regulation and control measures. With the ecotone in the west Songnen Plain as an example, and based on the studies of the topography, physiognomy, soil, vegetation, and their geographic distribution in the ecotone., this paper explained the structure of the ecological landscape, and quantitatively analyzed the ecological geo-chemical processes under different landscape conditions. In addition, this paper also tried to make coupling analyses to the ecologic succession and the landscape geo-chemical environment. Under current conditions, the succession of plant communities and the shift of soil landscape geo-chemical conditions in the west Songnen Plain are almost co-instantaneous, and these two factors can inter-determined under certain conditions.
This paper studied the spatial distribution characteristics and ecological effects of organic carbon and nitrogen in soils of Huolin River catchment wetland in horizontal and vertical levels. The results showed that the differences of horizontal and vertical distribution of organic carbon and nitrogen were very obvious, and of all the factors such as the period of wetting and drying cycles, leaching, plant and flood etc., the period of wetting and drying cycles was contents the critical one, which caused the differences. Soil organic carbon was significantly correlated with soil nitrogen (r = 0.977). The ratio of carbon and nitrogen (C/N) changed along with the humidity gradient, and soil pH values obviously influenced the concentration of organic carbon and nitrogen. The correlation of C/N values and organic carbon and nitrogen contents in wetland soil and in grassland soil were remarkably different, and the ecological effects mainly included production effect and clarification effect.
The piwi family genes are highly conserved during evolution and play essential roles in stem cell self-renewal, gametogenesis, and RNA interference in diverse organisms ranging from Drosophila melanogaster and C. elegans to Arabidopsis. Here we report the molecular characterization of hiwi, a human member of the piwi gene family. hiwi maps to the long arm of chromosome 12, band 12q24.33, a genomic region that displays genetic linkage to the development of testicular germ cell tumors of adolescents and adults (TGCTs), i.e., seminomas and nonseminomas. In addition, gain of this chromosomal region has been found in some TGCTs. hiwi encodes a 3.6 kb mRNA that is expressed abundantly in the adult testis. It encodes a highly basic 861-amino-acid protein that shares significant homology throughout its entire length with other members of the PIWI family proteins in Drosophila, C. elegans and mammals. In normal human testes, hiwi is specifically expressed in germline cells, with its expression detectable in spermatocytes and round spermatids during spermatogenesis. No expresssion was observed in testicular tumors of somatic origin, such as Sertoli cell and Leydig cell tumors. Enhanced expression was found in 12 out of 19 sampled testicular seminomas-tumors originating from embryonic germ cells with retention of germ cell phenotype. In contrast, no enhanced expression was detected in 10 nonseminomas-testicular tumors that originate from the same precursor cells as seminomas yet have lost their germ cell characteristics. Finally, no enhanced expression was detected in four spermatocytic seminomas-testicular tumors that most likely originate from germ cells capable of partial meiosis. Thus, hiwi is specifically expressed in both normal and malignant spermatogenic cells in a maturation stage-dependent pattern, in which it might function in germ cell proliferation.
The piwi family genes are crucial for stem cell self-renewal, RNA silencing, and translational regulation in diverse organisms. However, their function in mammals remains unexplored. Here we report the cloning of a murine piwi gene (miwi) essential for spermatogenesis. miwi encodes a cytoplasmic protein specifically expressed in spermatocytes and spermatids. miwi(null) mice display spermatogenic arrest at the beginning of the round spermatid stage, resembling the phenotype of CREM, a master regulator of spermiogenesis. Furthermore, mRNAs of ACT (activator of CREM in testis) and CREM target genes are downregulated in miwi(null) testes. Whereas MIWI and CREM do not regulate each other's expression, MIWI complexes with mRNAs of ACT and CREM target genes. Hence, MIWI may control spermiogenesis by regulating the stability of these mRNAs.
The spatial distribution characteristics of soil organic matter and nitrogen in the natural floodplain wetland were studied in this paper. The results showed that the vertical distributions of nutrients in floodplain wetland were very similar, and the horizontal distribution of them in surface soil were distinctly different. The highest concentration of nutrients was not in the frequently-flooded floodplain wetland where the concentrations of soil organic matter and total nitrogen were 2.36% and 2605.4 mg/kg, but in the floodplain with a certain flood frequency. The concentrations of soil organic matter in the one-year floodplain wetland and five-year floodplain wetland were 3.70% and 3.92%, respectively; and the concentrations of total nitrogen were 3666.4 mg/kg and 3125.6 mg/kg, respectively. The ratios of carbon and nitrogen were relatively low. All the factors such as cycling of dry and wet, underground underset, vegetation growth and pH values etc. influenced the distribution of soil organic matter and nitrogen in wetland.
The characteristics of vertical and horizontal variations of lead element(Pb) in soil-plant system of vertical zone in Changbai Mountain National Nature Reserve(CNNR) were studied. The results showed that Pb concentrations in soils of vertical zone are all above 25 mg/kg, and the average Pb concentration of each soil zone negatively correlates its degree of variation, i.e. brown coniferous forest soil zone has the lowest average Pb concentration of four soil zones, and the highest horizontal variation; however, mountain soddy forest soil has the highest average Pb concentration, and the lowest horizontal variation; the average concentration of plant Pb of each plant zone is lower than the worldwide average level of Pb in plant(Clarke), respectively, and plant Pb content order is consistent with soil Pb content order, but their horizontal variations are different from those in soil zones, the variation of mountain tundra forest zone is highest, but Betula ermanii forest zone the lowest. Vertical variation of plant Pb is obviously higher than that in soils with variation coefficient of 89.76%; the enrichment capability of plant for Pb is depended on the plant types and the different organs of plant; parent material and parent rock, pH values, soil organic matter and soil particle fraction etc. are the main factors influencing variations of Pb content in soil-plant system of vertical zone in CNNR.
All samples were divided into three groups and subjected to three different surface treatments, i.e. untreated group, group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h and group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h then heated at 600 degrees C for 1 h. After soaked in simulated body fluid for two weeks, a thin calcium phosphate coatings was precipitated on the surfaces of the two treated samples. Results of SEM and EDX showed that calcium phosphate coatings on the surfaces of the titanium samples etched and heated were more even than the titanium samples etched without heating. The analysis of XRD demonstrated the main component of calcium phosphate coating was hydroxyapatite.
The methyl isobutyl ketone-dimethyl benzene solution of sample was emulsified into emulsion by emulsifier Triton X-100. The standard addition method was used to determine with polyisobutylene emulsion as the reference. An analytical method for rapid determination of iron and nickel in crude oils by FAAS had been developed. A principle and method of preparing blank solution had been advanced. Choices of solvent and emulsifier, preparing blank solution were studied. The determination results were consistent with those obtained by ashing method-FAAS.
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Inspired by the concept of knowledge-based scoring functions, a new quantitative structure-activity relationship (QSAR) approach is introduced for scoring protein-ligand interactions. This approach considers that the strength of ligand binding is correlated with the nature of specific ligand/binding site atom pairs in a distance-dependent manner. In this technique, atom pair occurrence and distance-dependent atom pair features are used to generate an interaction score. Scoring and pattern recognition results obtained using Kernel PLS (partial least squares) modeling and a genetic algorithm-based feature selection method are discussed.