Biomedical subjects

Ming Dong

Publications and source records attributed to Ming Dong.

At least 37 records · Page 2Linked to original sources

PubMed2004

[Study on measuring host-guest ratio of inclusion compound of beta-CD-permethrin by IR].

Permethrin is one of the agrochemicals used in tea gardens currently with the characteristic of being easily decomposed in light. Permethrin with beta-cyclodextrin(CD) made into Inclusion Compound (IC) can increase its stability and reduce dosage to remain on the tea. Host/guest ratio is one of the important parameters of IC. The IC of permethrin with beta-CD was prepared by means of liquid phase method and characterized by using IR. The result of the IR proves that the characteristic absorption peaks of the host and guest are not changed by forming their IC. The host/guest ratio of the IC measured by IR is 1:1. Potassium sulfocyanate (KSCN) was chosen as an inside mark material, because it has only one strong absorption peak at 2100 cm(-1) and the peak was chosen as a quantitative peak of KSCN. The peak at 580 cm(-1) is the characteristic absorption of the wreath vibration of beta-CD and was chosen as a quantitative peak of beta-CD. KSCN and beta-CD were mixed with a certain quantity ratio and the mixture was analyzed by IR. The work curve of IR was established. A kind of new experimental method of measuring host/guest ratio of the IC was provided.

Calorimetry, Differential Scanning↗

PubMed2003

p53 alteration is not an independent prognostic indicator, but affects the efficacy of adjuvant chemotherapy in human pancreatic cancer.

BACKGROUND AND OBJECTIVES: Mutations in the p53 gene are found in more than 50% of human cancers and are observed in 60-80% of pancreatic cancers. The clinicopathologic implications of p53 abnormalities and their effects on the efficacy of the adjuvant chemotherapy for pancreatic cancer remain controversial. METHODS: We investigated the p53 status in core exon-4 to -9 (codon 33-331) by direct DNA sequencing in a series of 72 pancreatic cancers and analyzed the effects of p53 abnormalities on the patients' survival and the efficacy of adjuvant chemotherapy. RESULTS: p53 mutations were found in 62.5% (45/72) of cases, including 38 point mutations and 7 frameshift mutations. The subtypes of p53 mutations included 68.9% (31/45) transitions and 15.6% (7/45) transversions. 39.5% (15/38) of point mutations were CGT (Arg) to CAT (His) mutation at codon-273 of exon-8. 34.2% (13/38) of point mutations were CGG (Arg) to TGG (Trp) mutation at codon-248 of exon-7. Of seven frameshift mutations, four were seen at exon-4, two at exon-5, and one at exon-6. Of overall cases, p53 abnormalities were not associated with a poorly differentiated grade and an advanced stage. The relationship of adjuvant chemotherapy to survival is approaching statistical significance. Univariate analysis showed that in the p53 mutation group, the patients who received adjuvant chemotherapy had a better survival ratio than that of patients who did not do. Multivariate analysis indicated that in the group with p53 mutations, the significant factors for survival were adjuvant chemotherapy, histologic grade, and clinical stage. However, in the group with a wild-type p53 gene, only histologic grade was a significant factor. In addition, 34.7% (25/72) of the cases harbor p53 polymorphism mutation only at codon-72 of exon-4, which did not show any significant effect on the pathology, prognosis, and efficacy of adjuvant chemotherapy of the pancreatic cancers. CONCLUSIONS: A p53 abnormality was not an independent factor for evaluating the prognosis of patients with pancreatic cancer, but was a beneficial indicator for selecting a reasonable strategy of adjuvant chemotherapy against pancreatic cancer.

Adult↗

PubMed2003

Induction of primary virus-cross-reactive human immunodeficiency virus type 1-neutralizing antibodies in small animals by using an alphavirus-derived in vivo expression system.

We have studied the induction of neutralizing antibodies by in vivo expression of the human immunodeficiency virus type 1 (HIV-1) envelope by using a Venezuelan equine encephalitis virus (VEE) replicon system with mice and rabbits. The HIV-1 envelope, clone R2, has broad sensitivity to cross-reactive neutralization and was obtained from a donor with broadly cross-reactive, primary virus-neutralizing antibodies (donor of reference serum, HIV-1-neutralizing serum 2 [HNS2]). It was expressed as gp160, as secreted gp140, and as gp160deltaCT with the cytoplasmic tail deleted. gp140 was expressed in vitro at a high level and was predominantly uncleaved oligomer. gp160deltaCT was released by cells in the form of membrane-bound vesicles. gp160deltaCT induced stronger neutralizing responses than the other forms. Use of a helper plasmid for replicon particle packaging, in which the VEE envelope gene comprised a wild-type rather than a host range-adapted sequence, also enhanced immunogenicity. Neutralizing activity fractionated with immunoglobulin G. This activity was cross-reactive among a panel of five nonhomologous primary clade B strains and a Chinese clade C strain and minimally reactive against a Chinese clade E (circulating recombinant form 1) strain. The comparative neutralization of these strains by immune mouse sera was similar to the relative neutralizing effects of HNS2, and responses induced in rabbits were similar to those induced in mice. Together, these results demonstrate that neutralizing antibody responses can be induced in mice within 2 to 3 months that are similar in potency and cross-reactivity to those found in the chronically infected, long-term nonprogressive donor of HNS2. These findings support the expectation that induction of highly cross-reactive HIV-1 primary virus-neutralizing activity by vaccination may be realized.

AIDS Vaccines↗

PubMed2003

Association between pepsinogen C gene polymorphism and genetic predisposition to gastric cancer.

AIM: To identify a molecular marker for gastric cancer, and to investigate the relationship between the polymorphism of pepsinogen C (PGC) gene and the genetic predisposition to gastric cancer. METHODS: A total of 289 cases were involved in this study. 115 cases came from Shenyang area, a low risk area of gastric cancer, including 42 unrelated controls and 73 patients with gastric cancer. 174 cases came from Zhuanghe area, a high-risk area of gastric cancer, including 113 unrelated controls, and 61 cases from gastric cancer kindred families. The polymorphism of PGC gene was detected by polymerase chain reaction (PCR) and the relation between the genetic polymorphism of PGC and gastric cancer was examined. RESULTS: Four alleles, 31 0bp (allele 1), 400 bp (allele 2), 450 bp (allele 3), and 480 bp (allele 4) were detected by PCR. The frequency of allele 1 was higher in patients with gastric cancer than that in controls. Genotypes containing homogenous allele 1 were significantly more frequent in patients with gastric cancer than that in controls (0.33, 0.14, chi(2)=3.86, P<0.05). There was no significant difference between the control group of Zhuanghe and the group of gastric cancer kindred. But the frequency of allele 1 was higher in control group of Zhuanghe area than that in control group of Shenyang area and genotypes containing homogenous allele 1 were significantly more frequent in the control group of Zhuanghe area than those in control group of Shenyang area (0.33, 0.14, chi(2)=4.32, P<0.05). In the group of gastric cancer kindred the frequency of allele 1 was significantly higher than that in control group of Shenyang area (0.5164, 0.3571, chi(2)=4.47, P<0.05). Genotypes containing homogenous allele 1 were significantly more frequent in the group of gastric cancer kindred than those in control group of Shenyang area (0.36, 0.14, chi(2)=4.91, P<0.05). CONCLUSION: These results suggest that there is some relation between pepsinogen C gene polymorphism and gastric cancer, and the person with homogenous allele 1 predisposes to gastric cancer than those with other genotypes. Pepsinogen C gene polymorphism may be used as a genetic marker for a genetic predisposition to gastric cancer. The distribution of pepsinogen C gene polymorphism in Zhuanghe, a high-risk area of gastric cancer, is different from that in Shenyang, a low risk area of gastric cancer.

Alleles↗

PubMed2003

[Fractal characteristics of particle size distributions of mangroves soils in Yingluo Bay].

Based on fractal theory, the fractal characteristics of particle-size distributions of mangrove soils in Yingluo Bay (21 degrees 28'N, 109 degrees 43'E) were studied. The results show that the fractal dimensions of the soils ranged from 2.6837 to 2.8834, and decreased in the order of sand loam < light loam < medium loam < heavy loam < light clay. The fractal dimensions of the soils on exterior beach were lower than those on middle and inner beaches. There was a significant positive linear relationship between fractal dimension and soil salinity and organic matter content. The major factors that influenced the fractal dimensions of the soils were community type, soil texture, beach position, soil salinity, and soil organic matter content.

Algorithms↗

PubMed2003

[Growth and physiological features of Salix matsudana on the Mu Us Sandland in response to shading].

In a pot experiment, Salix matsudana was subjected to the unshaded, partial shading and shading treatments. The growth and physiological features of its branches were compared under contrasting light environments (i.e., the branches of entirely grew under unshaded condition (Bhh), entirely grew under shading condition (Bll), grew under unshaded condition and connected to different branches under shading condition (Bhl), and grew under shading condition and connected to different branches under unshaded condition (Blh)). The results showed that the leaf natality and mortality were higher in Bhl and Bll than in Bhh and Blh, respectively. Shading had significant effects on net photosynthesis and night respiration rates of four types of branches. The branch biomass, total branch length, shoot biomass and shoot weight ratio were higher in Bhl than in Bhh, and conversely, the number of branches, branch biomass, leaf area, leaf biomass, basal diameter, total branch length, shoot biomass and shoot weight ratio were smaller in Blh than in Bll.

Photosynthesis↗

PubMed2003

[Diverse boundaries between patches within the sandy landscape in Mu Us sandy land].

A terrestrial landscape is a mosaic of heterogeneous landforms, vegetation types, and land uses. Boundaries between neighbor patches become conspicuous components of ecological landscapes. The vegetation cover, plant species number, species similarity, soil organic C content, and soil organic N content crossing neighbor patches in Mu Us sandy land were investigated. The results showed that boundaries determined on the basis of each parameter differed, which compared favorably with the previous studies on ecotone dynamics and ecological boundaries delineation.

Ecology↗

PubMed2003

[Spatial heterogeneity of Ulmus pumila open forest ecosystem in Otindag sandy land].

Ulmus pumila open forest ecosystem plays an important role in Otindag Sandy Land. Using biostatistics (U test and Pearson correlation analysis) and geostatistics (Semivariogram analysis and Kriging interpolation), the spatial heterogeneity of soil organic matter (SOM), soil total nitrogen (STN), soil pH (SpH), soil water content (SWC), and the correlations between them, as well as their relationships with herbaceous coverage (HC) and Ulmus pumila were studied. The results showed that spatial heterogeneity and spatial dependence were apparent in SOM, STN, SpH, SWC and HC. With Kriging interpolation in the sampling area, the contour maps for these properties were drawn. Using the contour maps, the relationship between Ulmus pumila and spatial heterogeneity of the studied properties was investigated. The possible reason for the formation of fertility island under the Ulmus pumila trees in the ecosystem was discussed.

Ecosystem↗

PubMed2003

[Application of DNA extraction and analysis of its influence factors].

To explore influence factors of DNA extraction, the protease and phenol-chloroform method was used to extract DNA in whole blood, fresh tissues, frozen tissues embedding with OCT and tissues embedding in paraffin. It results that 200-300 microg DNA was extracted from 1 ml whole blood or 0.2 g fresh tissues or frozen tissue embedding with OCT. DNA extracted from paraffin specimen can be directly used in PCR amplification. Purity DNA can be extracted from four kinds of different tissues. OCT hasn't harmful effect on tissue DNA extraction.

English Abstract↗

PubMed2002

[Quantitative analysis of landscape conditions of the desertified sandy grassland in Ordos Plateau].

The landscape condition of the sandy grassland in southeast of Ordos Plateau was analyzed based on the data from field investigation along two intercepting 5 km transects. Summary on frequency of the patches showed that small-scale patches were prominent in this area, with 95% of total patches smaller than 50 m and average dimension of patches 15 m, while there were also a couple of large-scale mobile sandy patches. Environmental heterogeneity dependent on spatial scales was revealed by semivarogram in the sampling area. The large fractal dimensions of percent coverage of bare ground, close to 2, indicated dominant small-scale spatial variance. This result implies a relative stabilized landscape and also a desertified area.

China↗

PubMed2002

Clonal integration and its ecological significance in Hedysarum laeve, a rhizomatous shrub in Mu Us Sandland.

Hedysarum laeve, a rhizomatous clonal half-shrub, commonly dominates in inland dunes in semiarid areas of northern China. This species propagates vegetatively by the extension of horizontal rhizomes resulting in programmed reiteration of apical and/or axillary meristems. In this study, (14)C labeling and experimental defoliation were employed to test the photosynthate translocation within the interconnected parent-daughter ramet pairs. A proportion of (14)C-photosynthates was transported from the parent ramet into the daughter ramet, the roots of the daughter ramet, and the rhizome; these three components showed more than 70% sink activity after 24-h translocation. On the other hand, the basipetal translocation (from daughter ramet into parent ramet) was relatively small with sink activity of less than 5%, but sink activity of the rhizome exceeded 10%. Defoliation had an influence on the photosynthate translocation between parent and daughter ramets. The intact parent ramets significantly increased their (14)C-photosynthate translocation into defoliated daughter ramets when compared to intact daughter ramets. The daughter ramets transported significantly more (14)C-photosynthates to the defoliated parent ramets than to the intact parent ramets. A portion of (14)C-photosynthates was transported into the rhizome from both parent and daughter ramets, indicating that the rhizome is supported by both ramets for photosynthates. The clonal integration between ramets of the species through rhizome connection may confer benefit both to the ramets and the genet in adverse environments.

Journal Article↗

PubMed2002

Implication of thymidylate synthase in the outcome of patients with invasive ductal carcinoma of the pancreas and efficacy of adjuvant chemotherapy using 5-fluorouracil or its derivatives.

Thymidine synthase (TS) is a key enzyme in the synthesis of pyrimidine in the de novo pathway of DNA synthesis and a major target of 5-fluorouracil (5-FU), but the implications of TS regarding human pancreatic cancer have not been reported. We assessed the expression of TS in invasive ductal carcinoma (IDC) of the pancreas by immunostaining and evaluated its clinicopathological significance, especially its implications regarding the efficacy of chemotherapy with 5-FU or its derivatives. The expression of TS in the nuclei of pancreatic cancer cells in 72 primary lesions of resectable IDC and 30 distant metastases of unresectable IDC was examined by immunostaining using anti-TS polyclonal antibody and immunoreactivity was classified into three categories: negative (-), low (+) and high (2+). High TS immunoreactivity was detected in 43% (31 of 72) of the primary lesions of the resectable IDCs and in 47% (18 of 38) of the metastatic lesions of the unresectable IDCs. The high TS in primary lesions showed a significantly inverse correlation with the level of nodal involvement. High TS immunoreactivity had a significant influence on the outcome of patients with resectable IDC and the rate of survival of the high TS immunoreactivity group was significantly higher than that of the negative or low reactivity groups, although high TS immunoreactivity did not have a significant influence on survival of the patients with unresectable IDC. The implications of TS immunoreactivity regarding the efficacy of 5-FU-based adjuvant chemotherapy (ACT) was also assessed. The high TS immunoreactivity group showed significantly better survival in both the patients who received ACT and those who were treated by surgery alone, in the resectable IDC among patients with resectable IDC. In cases of unresectable IDC, there were no differences in survival between the high and low TS groups among the patients who received ACT and those who were treated by surgery. In conclusion, high TS immunoreactivity was found to be cogent in predicting the prognosis of patients with pancreatic IDC, but its implications regarding the efficacy of 5-FU-based ACT are still unclear.

Adult↗

PubMed2002

Expression of gastric cancer-associated MG7 antigen in gastric cancer, precancerous lesions and H. pylori -associated gastric diseases.

AIM: To investigate the relationship between the antigen MG7 antigen expression and gastric cancer as well as precancerous condition; to study the relationship between the MG7 antigen expression and H. pylori infection in benign gastric lesions in order to find out the effect of H. pylori infection on the process of gastric cancer development. METHODS: The level of MG7 antigen expression was determined by immunohistochemical method in 383 gastric biopsied materials. The intestinal metaplasia was determined by histochemistry method. The H. pylori infection was determined by HE stain, PCR and ELISA in 291 specimens, among which only 34 cases of H. pylori-associated gastric lesions were followed up. RESULTS: The positive rate of MG7 expression in normal gastric mucosa, intestinal metaplasia, dysplasia and gastric cancer increased gradually in ascending order (P<0.01). The positive rate of MG7 antigen expression in type III intestinal metaplasia of gastric mucosa was higher than that of type I and II intestinal metaplasia, being highly significant (P<0.05).The positive rate of MG7 antigen expression in superficial gastritis, atrophic gastritis and gastric cancer increased gradually (11.9 %, 64.8 %, 91.2 %, P<0.01). There was no significant difference between H. pylori-negative and H. pylori-positive intestinal metaplasia, atrophic gastritis and dysplasia of gastric epithelium in the positive rate of MG7 antigen expression. There was no expression of MG7 antigen in H. pylori-negative superficial gastritis. The positive rate of MG7 expression in H. pylori-positive superficial gastritis was 20.5 %, and the difference between them was significant (P<0.05). During following up, one of the three H. pylori negative cases turned positive again, and its MG7 antigen expression turned to be stronger correspondingly. 3 of 31 H. pylori positive cases were detected as early gastric cancer, among which one with "+++" MG7 antigen expression was diminished after H. pylori eradication. CONCLUSION: MG7 antigen expression is highly specific in gastric cancer and can be used as a good marker for screening of gastric cancer; type III intestinal metaplasia, atrophic gastritis and dysplasia should be followed up and MG7 antigen expression has high clinical value in the dynamic follow-up study; although the positive -MG7 in positive -H. pylori superficial gastritis show benign morphology in features, there is still the potential risk of developing into gastric cancer, hence special attention should be paid to those showing increasing MG7 antigen expression.

Antibodies, Monoclonal↗

PubMed2002

[MG7 expression in helicobacter pylori-related gastric diseases].

OBJECTIVE: To determine the influence of Helicobacter pylori (H. pylori) on gastric cancer-related antigen MG7 expression. METHODS: The H. pylori infection and the expression level of antigen MG7 in gastric mucosa were determined by HE stain, PCR, ELISA and immunohistochemistry in 291 patients with H. pylori-related conditions, among whom 34 were followed-up. RESULTS: No significant difference was found between H. pylori-negative and H. pylori-positive intestinal metaplasia, atrophic gastritis and dysplasia of gastric epithelium in positive rate of antigen MG7 expression. There was significant difference between H. pylori-negative and H. pylori-positive superficial gastritis in the positive rate of MG7 expression (P < 0.05). During follow-up, one of 3 H. pylori-negative cases turned to be H. pylori-positive, and its MG7 expression turned to be higher at the same time. Three of 31 H. pylori-positive patients were discovered as having early gastric cancer, among whom one with antigen MG7 expression (+ + +) was found to have a reduced Mg7 expression accompanied with H. pylori eliminutied after operation. CONCLUSION: There is correlationship between H. pylori infection and MG7 expression in superficial gastritis. Although the MG7-positive lesions with H. pylori infection shows a benign nature in morphology, they also have the potential risk of developing into gastric cancer. Therefore, they should be followed up, during which special attention should be paid to patients with increased MG7 expression.

Antibodies, Bacterial↗

PubMed2002

Clinicopathological significance of abnormalities in Gadd45 expression and its relationship to p53 in human pancreatic cancer.

PURPOSE: The growth arrest and DNA damage-inducible 45 gene (GADD45a) is one of the downstream mediators of the p53 gene that stimulates DNA excision repair. The present study was designed to assess the clinicopathological significance of GADD45a and p53 in resectable invasive ductal carcinomas (IDCs) of the pancreas. EXPERIMENTAL DESIGN: This study included 72 pancreatic IDC patients who received surgery between 1982 and 2001. Point mutations in exons 1 and 4 of GADD45a and the expression of the GADD45a gene product (Gadd45) and p53 protein were analyzed by direct DNA sequencing and immunohistochemistry. RESULTS: Point mutations were found in exon 4 of GADD45a in eight cases (13.6%). Gadd45 and p53 were expressed in 54.2% (39 of 72) and 47.2% (34 of 72) of the patients. The expression of Gadd45 did not necessarily correlate with that of p53. However, Gadd45 expression correlated significantly with the grade of the pT factor of the tumors. Coexpression analysis of Gadd45 and p53 indicated that in patients with p53(+) IDC, the Gadd45(+) group had a significantly lower survival rate than the Gadd45(-) group. Furthermore, Gadd45 expression had no effect on the efficacy of the adjuvant chemotherapy. Multivariate analysis indicated that pTNM (tumor-node-metastasis) stage, grade, and adjuvant chemotherapy were significant variables for survival. Furthermore, in the p53(-) group, there were no significant variables. In contrast, in the p53(+) group, pTNM stage, histological grade, and Gadd45 expression were significant variables. CONCLUSIONS: The frequency of GADD45a mutation is appreciable in human pancreatic IDC, and the expression of Gadd45, combined with that of p53, significantly affects the survival of patients with resectable IDCs of the pancreas.

Adult↗

PubMed2002

[Architectural plasticity of the stoloniferous herb, Duchesnea indica in response to different elevation].

Architectural plasticity of clonal plant may modify its ways of utilization of resources through clonal growth and be of ecologically importance. The plasticity of clonal architecture in response to ecological conditions at different altitudes in a stoloniferous herb, Duchesnea indica, was investigated in an experiment with different elevations of 400, 800, 1200, and 1600 m. The results showed that the change patterns of spacer length, ramet density, branching intensity, and branching angle of Duchesnea indica were in a quadratic curve when the elevation increased. The architectural plasticity of D. indica was simulated through dynamic Logistic model, and the imitative effect was statistically preferable. Combining with the resources utilization of Duchesnea indica under different environments, the architectural plasticity was also discussed in this paper.

Altitude↗

PubMed2001

Prospects of EGF Transgenic Mice Researches.

Genetic engineering in mice has proven to be a powerful tool for studying the specificity, complementarity and redundancy in the signalling cascades by altering the structure or expression of a single gene or a set of genes, from the ligands themselves to the specific receptors to the downstream signallingplayers. These models have provided a wealth of information about the effects of a number of oncogenes and growth factors. Transgenic and gene-targeted mouse lines have been used extensively to study the function of the EGFR and its ligands, insulin-like growth factor (IGF), their receptors and binding proteins. This mini-review highlights some of the major recent findings pertinent to the EGF and IGF-I/IGFBPS transgenic model. This mini-review summarizes the current knowledge about the actions of EGF and IGFBP in vivo based on the presently established transgenic mice. We focus on results obtained from the application of transgenic and knockout models to determine the roles of EGF, IGFs in the regulation of reproduction and growth development.

Journal Article↗

PubMed2000

ZNC(C)PR Induces Phosphorylation of CREB in Rat Hippocampus.

ZNC(C)PR can facilitate the learning and memory in rat. Transgenic experiments have revealed that long-term memory depended on cyclic AMP-response element binding protein, CREB. CREB phosphorylation at serine-133 is essential for it's transcriptional activity. Here, it was demonstrated that ZNC(C)PR could induce CREB phosphorylation at serine-133 in both rat hippocampus and rat hippocampus slices. ZDC(C)PR antagnist of ZNC(C)PR , PTX(inhibitor of G(o)/G(I) protein coupled receptor), GF109203x(inhihitor of PKC), PD98059( inhibitor of MAPK ) but not KN-62(inhibitor of CaMKII) could inhibit the phosphorylation of CREB induced by ZNC(C)PR.

Journal Article↗