Search PubMed⌕ Search

Biomedical subjects

D Wang

Publications and source records attributed to D Wang.

At least 505 records · Page 28Linked to original sources
PubMed1999

[A study on homozygous deletion, hypermethylation, mutation and expression of p16 gene in human breast cancer].

OBJECTIVE: To investigate the homozygous deletion (HZD), hypermethylation and mutation of p16 gene in human breast cancer and the relationship between the structural alterations of p16 gene and its expression. METHODS: PCR and PCR-methylation assay with silver staining (PCR-MASS) were used to detect HZD and hypermethylation of p16 gene exon 1 in 60 fresh breast cancers and 24 normal breast tissues adjacent to cancer (as control tissues). PCR-SSCP and DNA sequencing were used for the analysis of p16 gene mutation. Moreover, p16 gene and mRNA were also detected in the 60 cases. RESULTS: Of the 60 breast cancers, HZD was found in 7 cases, hypermethylation and mutation were found in 16 and 4 cases respectively, and the difference was statistically significant. The positive rates of p16 protein and mRNA in breast cancer were 28/60 and 39/60 respectively. CONCLUSION: The results demonstrate that several kinds of p16 gene structural changes exist in breast cancer. The structural changes of p16 gene cause abnormal p16 expression, the main mechanisms are hypermethylation, while HZD or mutation are the secondary causes. Abnormal expression of p16 gene then becomes involved in the development and metastasis of breast cancer.

Breast Neoplasms↗
PubMed1999

[A study on the loss of heterozygosity of multiple tumor suppressor genes in gastrointestinal metaplasia].

OBJECTIVE: To investigate the role of multiple tumor suppressor gene abnormality in gastrointestinal metaplasia (IM). METHODS: The loss of heterozygosity (LOH) of YNZ22, APC, MCC and DCC genes was examined by PCR-RFLP technique in 60 IM cases. RESULTS: LOH of YNZ22, APC, MCC and DCC genes were found in 19.4% (6/31), 12.0% (3/25), 13.0% (3/23) and 4.3% (2/47) respectively. IM was classified into types I, II and III. It was found that the LOH rates of each tumor suppressor gene of type III IM were higher than those of types I & II IM, but the difference was not significant (P > 0.05). Two cases of type III IM were found to also have 2 gene alterations (APC, MCC or YNZ22, MCC) respectively. All LOH were found in IM of adjacent carcinoma. None were found in IM of cancer-free patients. CONCLUSION: The alteration of tumor suppressor gene may play a role in the development and carcinogenesis of IM.

DNA↗
PubMed1999

[Relationship between smoking and drinking and herniation of intervertebral disc].

To study whether there is relationship between smoking and drinking and herniation of intervertebral disc, we investigated 214 patients who had been proved with herniation of intervertebral disk during 1986-1996. The results were that in the younger (< or = 35 year old), no matter whether they drank or not, the number of smoker in the patients with herniation of intervertebral disc was more than that in the control group; no matter whether they smoked or not, the number of drinker in the patients with herniation of intervertebral disc was more than that in the control group.

Adolescent↗
PubMed1999

[Examination of human herpesvirus-6 antibody in blood patients serum].

To know the infection state of human herpesvirus-6(HHV-6) in leukemia, lymphoma, myeloproliferative disorder syndrome, and multiple myeloma, indirect fluoroimmunoassay was taken to examine the rate of HHV-6's antibody. The results were that: the patient's rate of HHV-6 antibody was 75.6% (149/197), the blood donor's rate was 45.6% (115/252), there was a significant difference between them (P < 0.01). The results show that the examined patients are infected by HHV-6, which has a good relationship with leukemia, lymphoma, myeloproliferative disorder syndrome, and multiple myeloma.

Adolescent↗
PubMed1999

[Risk state analysis on lung cancer of male in Xuanwei, China].

The analysis of lung cancer risk factors among male population was based on the data of a retrospective cohort study conducted during 1976-1996 in Xuanwei, China. The results verified that the indoor air pollution from burning smoky coal was the main cause of high lung cancer mortality, and found that cigarette smoking was also significantly related with the lung cancer mortality. Using risk state analysis theory, fuel types(including household stove improvement), smoking and the history of chronic bronchitis were selected as the covariance for the analysis. A risk state analysis model for male lung cancer in Xuanwei was established. The model can be used to quantitatively estimate the risk of lung cancer and to determine high risk population and individuals. The model is helpful for the prevention of lung cancer in Xuanwei.

Adult↗
PubMed1999

[Classification distribution and medicinal sorts of endemic plants in Anhui province].

OBJECTIVE: To explore the natural resources of endemic medicinal plants in Anhuei, for reference in regional study of Chinese medicines. METHOD: Investigating the natural resources of medicinal plants in Anhuei and collating and studying the findings. RESULT AND CONCLUSION: There are 109 species of 37 families, of which Aristolochiaceae, Ranunculaceae, Crassulaceae, Cucurbitaceae, Labiatae, Liliaceae and Berberidaceae, Compositae, Orchidaceae are of greater medicinal value.

Aristolochiaceae↗
PubMed1999

[A study on producing areas of Chinese flos Dendranthematis].

OBJECTIVE: To probe into the cultural environment and changes of producing areas of different species of Chinese Flos Dendranthematis. METHOD: On-the-spot investigation and literature study. RESULTS: A clearer idea has been gained on the geographical distribution, growing environment and changes of producing areas of Gongju, Hangju, Chuju, Boju, Huaiju and Jiju. CONCLUSION: Different environments fit for the growth of different species of Flos Dendranthematis. The present study provides some valuable information on the cultivation and development of Chinese Flos Dendranthematis.

Asteraceae↗
PubMed1999

[An experimental study on the biological basis of cortex-to-cortex bone healing after oblique ramus osteotomy].

This study was designed to elucidate biological basis of cortex-to-cortex bone healing after oblique ramus osteotomy. 12 rhesus monkeys were subjected to oblique ramus osteotomy bilaterally, and the operated sites were examined by microvascular irrigation section and histology techniques. The results showed that, besides the blood supply from the attachment of lateral pterygoid muscles and capsule of temporomandibular joint to the medial segments, the blood supply from the attachment of medial pterygoid muscles also played an important role. Cortex-to-cortex bone healing was achieved by the formation of a large volume of scab surrounding the operated sites. It is concluded that oblique ramus osteotomy has its good biological basis both in blood supply and cortex-to-cortex bone healing process.

Animals↗
PubMed1999

[Species evolution of Chinese flos Dendranthematis].

OBJECTIVE: To probe into the history and current situation and main producing areas of different species of Chinese Flos Dendranthematis. METHOD: On-the-spot investigation, cultivation observation and literature study. RESULTS: Morphological characteristics of different species of Flos Dendranthematis were clarified, and the historical changes of these species were studied. CONCLUSION: Congju is related to Hangju. Boju is related to Huaiju. Jiju and Qiju, and Chuju is a distinctive species. These findings are important for the cultivation and processing of Chinese Flos Dendranthematis.

Asteraceae↗
PubMed1999

[The effects of combined use of multiple growth factors on proliferation and differentiation of human osteoblast-like cells].

Four growth factors PDGF, bFGF, IGF-II and TGF-beta, which is believed to have biological effects on bone cells, were examined in this study. The aim was to assess the effects of combinations of three and four growth factors on the proliferation and differentiation of osteoblast-like cells. The incorporation of 3H-TdR, 3H-Proline of osteoblast-like cells and alkaline phosphatase content of the cells were tested. The results showed the combinations of three and four growth factors stimulated the synthesis of DNA, collagen and ALP of osteoblast-like cells. These four growth factors interacted synergistically. The combinations of three and four growth factors showed stronger promoting effect on osteoblast-like cells, compared with the combinations of two growth factors. These findings suggest that the combined use of growth factors be a potential way of bone defect reconstruction and treatment of human bone disease.

Cell Differentiation↗
PubMed1999

[A dynamic study of influences of TMJOA on TMJ disc].

OBJECTIVE: To learn the changes of TMJ disc positions under the influences of TMJ Osteoarthrosis(TMJOA). METHODS: The TMJOA experimental animal model was established by 12 goats. The TMJ disc positions were observed and recorded at different intervals, (1 month, 2 months, 3 months, 4 months and 6 months) then the pathological changes of TMJ specimens were also studied. RESULTS: Significant anteromedial shift of TMJ disc position was observed in some certain TMJOA phases and became more obviously along with the disease progress. CONCLUSION: The shift of TMJ disc may be the secondary change of TMJOA.

Animals↗
PubMed1999

[Cloning and sequence characterization of heavy chain variable region gene from hybridoma cells secreting MAB against VEGF].

OBJECTIVE: To clone the variable region of heavy chain (VH) gene from hybridoma secreting monoclonal antibody against human vasoendothelial growth factor (VEGF) for construction of recombinant antibody (scFv). METHODS: One step method was used to extract total RNA and degeneration primer was used to amplify the cDNAs by retropolymerase chain reaction (RT-PCR), then the products were inserted to T-vector and its sequence was analysed. RESULTS: The VH gene contained 369 base pairs encoding 123 amine acid resides. Analysis of the nucleotide sequence of the light chain variable region revealed that the VH sequence was 87% identical to the sequence present in mouse Ig VH region. CONCLUSION: The VH gene was 369 bp. According to Kabat classification, the VH gene belonging to mouse kappa light chains subgroup I (A), resulting from VH-D-JH4 rearrangment.

Amino Acid Sequence↗
PubMed1999

[Design and synthesizing of human vascular endothelial growth factor (VEGF) peptide].

OBJECTIVE: To predict continuous epitopes of VEGF using synthetic peptide of VEGF as antigen to produce anti-VEGF-peptide monoclonal antibody. METHODS: According to amino sequence of VEGF189, antigen index program and Goldkey soft were used to predict VEGF epitopes, and the peptide containing one of predicted epitopes was synthesized by 430A Peptide Synthesizer. RESULTS: The NH2-terminal 1-26 amino acid sequence of VEGF was determined as synthetic peptide and synthesized. CONCLUSION: The predicted epitope of VEGF was synthesized, which provided an effective method when lacking of VEGF.

Amino Acid Sequence↗
PubMed1999

[Effects of two growth factors combination on the proliferation and differentiation of human osteoblast-like cells].

OBJECTIVE: To examine the effects of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-II) and type beta transforming growth factor(TGF-beta) which were believed to have biological effects on bone cells on human osteoblast-like cells. METHODS: 3H-TdR, 3H-Proline and alkaline phosphatase of the osteoblast-like cells were tested to study the combinating effects of different growth factors on the proliferation and differentiation of osteoblast-like cells. RESULTS: The combination of different growth factors had promotive effect and synergic interact on proliferation and differentiation of osteoblast-like cells. CONCLUSION: The phenomena indicate that the combination of two growth factors will enhance the biological effects of bone formation.

Cell Differentiation↗
PubMed1999

[Phenotypic changes of mandibular condylar cartilage cells during subculture].

OBJECTIVE: To demonstrate the phenotypic changes of mandibular condylar cartilage(MCC) cells during subculture in vitro. METHODS: MCC cells were harvested from human fetus by digestion of collagenase and cultured in DMEM supplemented with 10% newborn calf serum, then they were passaged when reached confluence. Morphological changes were observed under phase-contrast microscope. Type II collagen, proteoglycan synthesis and type I, II and III procollagen mRNA levels were also studied in serial monolayer cultures. RESULTS: During subculture, type II collagen and proteoglycan synthesis were decreased, being accompanied by a lower type II collagen mRNA level. In contrast, type I and III procollagen mRNA levels were elevated progressively. The morphology of polygonal-shaped chondrocytes was lost to the bipolar fibroblastic cells. CONCLUSION: Passage and culture can affect the phenotypic property of MCC cells.

Cells, Cultured↗
PubMed1999

[Effects of growth factors on DNA and collagen synthesis of human mandibular condylar cartilage cells].

OBJECTIVE: To investigate the effects of transforming growth factor-beta 1 (TGF-beta 1), insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor(bFGF) on DNA and collagen synthesis of mandibular condylar cartilage(MCC) of human fetus. METHODS: Cell culture, 3H-TdR and 3H-Proline incorporation methods were used. MCC cells were harvested from 4 to 5 months old human fetus. Cells were seeded at 2 x 10(4)/well on 96-well Plate. After synchronization, medium was replaced by DMEM containing 0.4% NCS with various growth factors and concentrations. RESULTS: bFGF stimulated the DNA synthesis significantly, and IGF-I had less effect, while the effect of TGF-beta 1 was insignificant. For collagen synthesis, bFGF caused a dose-dependent increase(60%). A greater effect(98%) was achieved when IGF-1 was added. In contrast, TGF-beta 1 could inhibit collagen synthesis (24%). CONCLUSION: Growth factors play an important part in the proliferation and matrix synthesis of MCC cells, which might be of potential application in treating cartilage destructive lesions.

Cell Division↗
PubMed1999

[Evaluation of methods of drug release rate in root canal disinfection controlled-release delivery system containing metronidazole].

OBJECTIVE: To measure the release rate of drug in controlled-release delivery system containing metronidazole. METHODS: Drug release tests in vitro, in vivo and through the roots of extracted teeth were performed. The release rate of metronidazole was calculated after 1 day, 3 days, 7 days and 10 days, and the results were statistically analyzed. RESULTS: Significant difference was observed among the total drug release rate in vitro, in vivo and through the roots of extracted teeth (P < 0.01). There was no statistically significant difference between the release test in vivo and through the roots of extracted teeth in vitro (P > 0.05). CONCLUSION: The method of using extracted teeth and the controlled release medium at 37 degrees C, pH7.4 was close to the situation in vivo, and it was an effective method to measure the drug release rate of the root canal disinfection controlled-release delivery system.

Anti-Infective Agents, Local↗