Biomedical subjects

Z Dong

Publications and source records attributed to Z Dong.

At least 127 records · Page 7Linked to original sources

PubMed2000

[The expression level of the transfected hEGF gene to cultured human epidermal cells].

OBJECTIVE: To study the stable expression levels of cultured human epidermal cells transfected with a hEGF-plasmid. METHODS: The 60%-70% confluent cultured human epidermal cells were transfected with a pBK-Signal-EGF plasmid-construct mediated by lipofectAMINE. After screening of G418 successfully transfected, clone forming cells were picked and subcultured for several weeks. To detect hEGF expression levels and to determine long term transgenic stability a specific ELISA was used. RESULTS: (1) hEGF plasmid constructs were successfully introduced into cultured human epidermal cells. (2) Transgenic expression still persisted after four subcultures. (3) hEGF expression levels could be detected in the medium over a six-week period. CONCLUSIONS: The stable expression of hEGF was obtained after gene transfected with the pBK-Signal-EGF plasmid mediated by lipofectAMINE.

Cell Division↗

PubMed2000

[Study on pathogenicity of sputum from cavity of sputum negative patients with pulmonary tuberculosis after short course chemotherapy].

OBJECTIVE: To find out whether or not the sputa of pulmonary tuberculosis(PTB) patients with cavitation but sputum negative have pathogenicity after short course chemotherapy. METHODS: Guinea pigs were inoculated with sputa of PTB patients who were with cavitation but sputum negative after having finished short course chemotherapy. Then their body weight, enlargement of local lymph nodes and other ordinary symptom were observed. Six weeks later, pathological changes of TB in the internal organs were examined by dissecting these guinea pigs. Culture and drug resistance test of tubercle bacillus were also conducted. All of which were with negative and positive controls. RESULTS: Of the 63 cases included, 3(5%) patients' sputa resulted in tuberculous nodulation varying in amount in lung, liver and spleen of these guinea pigs, and the culture for tubercle bacillus of these sputa was positive too. CONCLUSIONS: 5% of sputum collected from PTB patients with cavitation but sputum negative still show pathogenicity after short course chemotherapy. For the cases with drug-resistant PTB and slow sputum negative conversion, the treatment should be prolonged and tubercle bacilli in their sputa should be monitored.

Animals↗

PubMed2000

[Selection and characterization of human antibodies against vascular endothelial growth factor from human phage display antibody library].

OBJECTIVE: To select anti-VEGF (vascular endothelial growth factor) antibodies (Fab fragments) from human phage display antibody library and to identify their specification and activities. METHODS: Human immunoglobulin heavy chain and light chain genes were separately amplified by RT-PCR from human peripheral lymphocytes using family specific primers and signal sequences of immunoglobulin. Human antibody library was constructed by phage display technology, and phage Fab antibodies to VEGF were screened from this library. ELISA, Western blot and (3)H-thymidine incorporation assays were used for the specification and neutralization activities of these Fab antibodies. Sequencing analysis was carried out for further identification of the antibodies. RESULTS: The repertoire of human phage display Fab library was 1.5 x 10(8). After 4 round panning with VEGF(121), 280 clones were checked for their binding activities with ELISA and 12 clones could bind to VEGF(121) specifically. Western blot demonstrated that bacterially expressed soluble Fab could specifically recognize VEGF. Results of (3)H- thymidine incorporation showed that one clone of soluble Fab could neutralize the mitogenic activity of VEGF(165) on HUVEC. Sequencing analysis showed that the obtained V(H) gene belonged to human VH6 subgroup and the light chain was VJC rearranged human VL4 gene. CONCLUSIONS: Human anti-VEGF antibodies can be obtained from human phage display library, which provides a basis for preparation of high affinity human anti-VEGF monoclonal antibodies through antibody engineer technique.

Antibodies↗

PubMed2000

[The clinical significance of lung resistance protein (LRP) gene expression in patients with acute leukemia].

OBJECTIVE: To investigate the relationship between the expression of lung resistance protein (LRP) gene and drug resistance in patients with acute leukemias (AL). METHODS: Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR)was used to examine the expression of LRP gene in AL patients and 15 normal subjects. Beta(2) microglobulin (beta(2)MG) was used as internal reference. LRP/beta(2)MG ratio >or= 0.3 was defined as LRP positive. RESULTS: The positivity percentage of LRP gene expression in newly diagnosed group was 32.4%. The first complete remission rate was 84.0% and 33.0% in LRP negative and LRP positive patients, respectively. The difference was significant (P < 0.005). The expression level of LRP mRNA and the positivity percentage of LRP in relapsed/refractory group were significantly higher than that in newly diagnosed group (P < 0.01). The expression level of LRP gene in normal subjects and long-term survival groups was very low and correlated with FAB subtypes. The mdr-1 gene was examined simultaneously in 61 AL patients. No significant correlation was found between the expression of LRP and mdr-1 gene (P > 0.5). Coexpression of LRP and mdr-1 genes in the same AL patient might result in the worst prognosis. CONCLUSION: High expression of LRP gene leads to clinical drug resistance and is an unfavorable factor to AL patients of prognosis.

Acute Disease↗

PubMed2000

[Dynamic analysis of junctional sequences of T cell receptor (TCR) delta and gamma gene rearrangement in childhood with acute lymphoblastic leukemia].

OBJECTIVE: To explore the junctional sequence difference of T cell receptor delta and gamma gene rearrangement in childhood acute lymphoblastic leukemia (ALL) at diagnosis, complete remission (CR) and relapse. METHODS: By using the T-vector molecular cloning and sequencing and polymerase chain reaction, the junctional sequences of TCRdeltaV-D and TCRgammaV-J were dynamically analyzed in 34 bone marrow samples of ALL. RESULTS: The junctional sequence of TCR delta, gamma gene showed significant difference and regularity before and after remission and during relapsed periods. The sequence of TCRdeltaV-D were analyzed in 24 samples from ALL. Among them, the intact Vdelta2 and 5'Ddelta3 sequences were observed in 10 samples at diagnosis, of which 7 samples had T-->C mutation in Ddelta3 nonamer sequence. The deletions of rearranged Vdelta2, 5'Ddelta3 and Ddelta3 haptamer sequences were found in 11 complete remission (CR) samples with ALL, but none had T-->C mutation in Ddelta3 nonamer sequence. The deletion rate of Vdelta2 or Ddelta3 sequences and the T-->C mutation in Ddelta3 nonamer sequence were extremely differed between samples at diagnosis and in remission (calculate exact probabilities P = 0.001). The junctional rearrangement sequence of 5'Ddelta3 sequences tended to remain intact in 3 relapsed samples. The findings of TCRgammaV-J sequences were similar to that of TCRdeltaV-D in 10 ALL patients. CONCLUSION: The difference of TCRdeltaV-D and TCRgammaV-J junctional sequences were related to the development, therapeutic effectiveness and outcome in ALL.

Child↗

PubMed2000

[The significance and expression of vascular endothelial growth factor on nasal inverted papillomas].

OBJECTIVE: To determine the expression of vascular endothelial growth factor (VEGF) and its receptor in nasal inverted papillomas (NIP) and to clarify the function of VEGF in the establishment of NIPs. METHOD: VEGF and its receptor, fetal liver kinase-1 (flk-1) expression were examined by immunohistochemistry using SP method in sections of NIPs from 11 patients and inferior turbinates from 6 patients with chronic simple rhinitis. An automatic image analyzer was used to detect the staining results. Gray scale, a half-quantitative parameter, was used to describe the expression of VEGF and flk-1. RESULT: It showed that all the epithelium in NIPs, together with vascular and stroma adjacent to the epithelium, expressed different degree of VEGF. The VEGF expression in epithelium was significantly stronger in NIPs than that in inferior turbinates (P < 0.001). The expressions of both VEGF and flk-1 in vascular endothelium were more intense in NIPs than that in inferior turbinates (P < 0.001, P < 0.001). Flk-1 positive expression was observed in epithelium of NIPs but not in inferior turbinates. CONCLUSION: The results suggest that VEGF participate in the growth of NIPs, part of which shows the characteristics of containing plenty of blood vessels and being bloody in operation. The enhanced expression of VEGF may also play a key role in the development of edematous stroma. The expression degree of VEGF in the epithelium may be identified as one of the parameters of judging the propensity of NIPs' malignant transformation.

Aged↗

PubMed2000

[Purification and characterization of an endo-beta-1, 4-mannanase from Bacillus subtilis BM9602].

An extracellular neutral endo-beta-mannanase(endo-beta-1, 4-D-mannan mannanohydrolase, EC 3.2.1.78)of Bacillus subtilis BM9602 was purified to electrophoretic homogeneity by ammonium sulfate precipitation and DEAE-cellulose DE22 chromatography with 45.5 fold and 5.9% yield. It's molecular weight and pl value were 35 kD by SDS-PAGE and 4.5 by isoelectric focusing, respectively. The enzyme was the most active at pH 5.8. The optimum temperature of the enzyme activity was 50 degrees C. The enzyme was stable at pH 6.0-8.0 and below 50 degrees C. The activity of the enzyme was inhibited by Hg2+, Ag+ strongly. For various substrates, such as locust bean gum, guar gum, sesbania gum and konjac gum, Km and Vmax value of the enzyme were 3.8, 14.9, 11.3, 2.4 mg/mL, and 24.5, 86.5, 38.4, 19.8 mumol.min-1.mg-1, respectively. The enzyme hydrolize various plant beta-mannans, with valuable oligosaccharides and without monosaccharide.

Bacillus subtilis↗

PubMed2000

[Nasal cavity volume and nasopharyngeal cavity volume in adults measured by acoustic rhinometry].

OBJECTIVE: To investigate the range of normal value of total nasal cavity volume(NV) and total nasopharyngeal cavity volume (NPV) of healthy adults. METHOD: Six hundred and fifty-nine healthy adults and eighty-two adults of chronic rhinitis were measured with acoustic rhinometry. RESULT: The range of NV was 29.922-37.481 cm3 and NPV was 29.369-44.159 cm3. Comparing healthy adults with adults of chronic rhinitis, there was a significant difference in NV. CONCLUSION: Acoustic rhinometry suited for objective assessment of the nasal airways in adults. It was demonstrated that these data could provide available information for the study of nasal physiology and pathophysiology, as well as for the diagnosis and judgement of therapeutic effectiveness of nasal diseases.

Adolescent↗

PubMed2000

[The lamina papyracea fracture reduction under nasal endoscope].

OBJECTIVE: To evaluate the clinical results of blow-out laminapapyracea fracture reduction under nasal endoscopy. METHODS: All 6 cases had endophthalmos and blepharophimosis. Four cases also complained of diplopia. The horizontal and coronal CT of orbit showed the lamina papyracea fracture clearly. The degree and range of the lamina papyracea displacement was measured on CT films. The reduction under nasal endoscope was performed with local and topical anesthesia. We selected the Meeserklinger's route of entry. The uncinate process, ethmoidal bulla, and ethmoidal cells were removed successively. Then, with the help of a tonsil dissector, the lamina papyracea was pushed outward and replaced and was supported with iodoform gauze. After 2 to 3 weeks, the gauze was removed. RESULTS: The endophthalmos and diplopia disappeared in all cases. No postoperative complications occurred. With 0.5-2 years follow-up, the degree of the endophthalmos was stable within 2 mm. CONCLUSION: The reduction under nasal endoscope has many advantages such as short route of entry, simple performance, and no facial scar. It is a good operative option to correct the lamina papyracea fracture.

Endoscopy↗

PubMed2000

[The secretion of chemokine RANTES in epithelial cells of nasal polyps and its significance].

OBJECTIVE: To investigate the effect of RANTES(regulated upon activation, normal T cell expressed and secreted) on chemotaxis, migration and accumulation of eosinophils in nasal polyps during epithelial immune responses. METHODS: The epithelial cells were obtained from nasal polyps and inferior turbinates in patients with snoring, and cultured for 24 and 48 hours with IL-1 beta(25 micrograms/L, 50 micrograms/L). RANTES was measured in the culture supernatant by ELISA. RESULTS: 1. On incubation with IL-1 beta, the epithelial cells from inferior turbinate and nasal polyps released 1.5-10 fold and 10-20 fold greater amounts of RANTES respectively than unstimulated samples. Significant increase in levels of RANTES was found in both groups(P < 0.001); 2. There was no difference between nasal polyp and inferior turbinate before incubation with IL-1 beta(P > 0.05) in the level of RANTES. After IL-1 beta stimulation, the concentration of RANTES was higher in polyp than in inferior turbinate (P < 0.001); 3. The expression of RANTES in both groups was dose-dependent and time-dependent upon stimulation of IL-1 beta. CONCLUSION: The epithelial cells of nasal mucosa are active end-organs, capable of releasing chemokine RANTES. In nasal polyps, RANTES has chemotactic activity for eosinophils and other inflammatory cells. It could affect the chemotaxis and eosinophil function and may play an important role in polyp formation.

Adult↗

PubMed2000

[Expression of apoptotic gene and FGF on olfactory bulb of rat and its significance].

OBJECTIVE: To study the expression and distribution of apoptotic gene Bcl-2 and Bax on olfactory of rat, and its relation with the FGF and to investigate the mechanism of senile dysosmia. METHODS: Ten young (3 months) and ten senile rats (24 months) were used in this study. After the removal of the heads of these rats, olfactory bulb were immediately fixed with neutralized formalin, followed with paraffin-embedding, serial sectioning, immunohistochemiscal staining and microscopic observing. RESULTS: The positive expression rate of Bcl-2 and FGF on olfactory bulb in young rats was significantly stronger than that in senile rats (P < 0.01). The positive expression rate of Bax in senile rats was a little stronger than that in young rats, but the differences were not statistically significant. (P > 0.05) CONCLUSION: The expression of FGF and anti-apoptotic gene Bcl-2 on olfactory bulb decrease with the increase of age. This suggests neuron apoptosis on olfactory bulb are regulated by neurotrophic factor, and directly related with senile dysosmia. The mitral cell apoptosis as a result of FGF decreased on olfactory bulb may play a key role in the senile dysosmia.

Animals↗

PubMed2000

[Primary study of Na+ channels in the epithelial cells of nasal polyps and of the effect of IL-1 beta on Na+ channels].

OBJECTIVE: To investigate the relationship between Na+ channels and nasal polyps and to study the effect of IL-1 beta on Na+ channels of epithelial cells of human normal nasal turbinate (NT) and nasal polyps (NP). METHODS: Serum-free cultured epithelial cells of NT from obstructive sleep apnea syndrome patients and NP were studied on collagen gel-coated membranes at an air-liquid interface using the patch-clamp technique in the cell-attached configuration. RESULTS: (1) The three Na+ absorption-related factors(the incidence of Na+ channels, the conductance of Na+ channels and the open probability of Na+ channels) were compared in NT cells and NP cells. There was no difference between NT and NP cells in the incidence(P > 0.05) and in the conductance(P > 0.05). However, the open probability was higher in NP cells compared to NT cells(P < 0.01). (2) Application of IL-1 beta increased significantly in the open probability of Na+ channels in NT and in NP cells (P < 0.01), the conductance of Na+ channels in NP cells was strongly increased by IL-1 beta(100 ng/ml)(P < 0.01). CONCLUSIONS: (1) The formation of NP is significantly correlated with increased Na+ absorption, the prolonged open time of Na+ channels is one of the most important factors. (2) IL-1 beta may upregulate Na+ permeability by prolonged open time of Na+ channels and increased conductance of Na+ channels, increased absorption of Na+ may lead to the growth and enlargement of NP.

Adolescent↗

PubMed2000

[Expression of cell proliferation and apoptosis gene associated protein on nasal polyps and its significance].

OBJECTIVE: To further understand the pathogenic mechanism of nasal polyps, namely the cells proliferation and apoptosis in nasal polyps tissue. METHODS: The proliferation cell nuclear antigen (PCNA), apoptosis associated gene protein (Bcl-2, Bax) were determined in 26 tissue samples of nasal polyps and 14 controls from normal inferior turbinates respectively. RESULTS: (1) The positive expression e of PCNA, Bcl-2 and Bax were significantly higher in epithelium of nasal polyps than the controls, and the expression rate of Bcl-2/Bax, however, tended equipoise. (2) The expression of Bcl-2 were significantly stronger than Bax in glands, eosinophils of nasal polyps tissue, and there were not significant differences in inferior turbinates. CONCLUSION: There is strongly proliferation activity in the epithelium of nasal polyps, and expression imbalance of Bcl-2/Bax may be one of the important factors of eosinophilia in nasal polyps tissue.

Adult↗

PubMed2000

Effect of VL and VH consensus sequence-specific primers on the binding and expression of a mini-molecule antibody directed towards human gastric cancer.

OBJECTIVE: To construct ScFv and Fab from murine anti-gastric cancer monoclonal antibody (mAb)3H11. METHODS: At first, 3H11 ScFv and Fab were constructed with V genes PCR amplified by degenerate primers for FR1. The bacterial expressed 3H11 Ab fragments showed no antigen binding activity. Then, phage antibody library and random mutated library were constructed from 3H11 hybridoma cells and panning selection was perfomed. Again the identification of positive clone was failed. Finally the N-terminal sequences of V regions were resumed to 3H11 original sequences by site-directed mutagenesis via PCR. RESULTS: Binding activity to gastric cancer cells was detected only from N-terminal sequence corrected 3H11 ScFv and Fab,though the expression of the Ab fragments was not affected. Correction of either VL or VH N-terminal sequences could partially resume the antigen binding activity. CONCLUSION: Sequence changes of V region N terminal introduced by PCR may seriously affect antigen binding without affecting the expression of antibody.

Animals↗

PubMed2000

[Coordination chemistry and Raman spectra of acetylide dianion].

This paper shows the syntheses of double salts of silver acetylide with various soluble silver salts, investigations on the coordination modes of acetylide dianion and their Raman spectra, discussion of the relationship between the coordination chemistry of acetylide dianion and the bind mode of N2 molecule in the FeMoco factor of nitrogenase. The results present that the bind mode of N2 molecule inside the FeMoco factor of nitrogenase is more reasonable.

English Abstract↗

PubMed2000

[Infrared spectra and Raman spectra of monoclinic RblnS2 and CsInS2].

Monoclinic RbInS2 and CsInS2 were prepared by the traditional flux method and their IR and Raman spectra were studied. The IR and Raman absorption bands of CsInS2 shift to lower frequency compared with RbInS2. IR and Raman spectra show that monoclinic RbInS2 and CsInS2 exhibit good infrared transmission.

English Abstract↗

PubMed1999

Freshly fractured crystalline silica induces activator protein-1 activation through ERKs and p38 MAPK.

The transcription factor activator protein-1 (AP-1) reportedly plays an important role in the induction of neoplastic transformation and multiple genes involved in cell proliferation, differentiation, and inflammation. To investigate the mechanisms of silica-induced carcinogenesis, AP-1-luciferase reporter transgenic mice were used as an in vivo model, whereas the JB6 mouse epidermal cell line and a rat lung epithelial cell line were employed as in vitro models to study the effects of silica at the molecular level. Freshly fractured silica caused an 8-fold increase in AP-1 activity in JB6 cells and a 2.5-fold increase in rat lung epithelial cells. The induction of AP-1 activity in cultured cell lines was time- and dose-dependent. Intratracheal administration of silica was also able to induce AP-1 transactivation in transgenic mice. AP-1 activation was first observed at 2 days after silica administration and reached its maximum at 3 days post-exposure of the mice to silica. The signal transduction pathways for AP-1 activation were also investigated using these cell lines. The results demonstrate that freshly fractured silica stimulates mitogen-activated protein kinase (MAPK) family members, as determined by the phosphorylation of p38 MAPK and extracellular signal-regulated protein kinases (ERKs). Inhibition of ERKs with PD98059 or of p38 with SB203580 significantly inhibited silica-induced AP-1 activation. These findings demonstrate for the first time that freshly fractured silica induces AP-1 activation, which may be mediated through p38 MAPK and ERK pathways. Unraveling the complex mechanisms associated with these events may provide insights into the initiation and progression of silica-induced carcinogenesis.

Animals↗

PubMed1999

JNK activation is required for JB6 cell transformation induced by tumor necrosis factor-alpha but not by 12-O-tetradecanoylphorbol-13-acetate.

Signal transduction via mitogen-activated protein kinase pathways plays a key role in a variety of cellular responses, including cell proliferation, differentiation, tumor promotion, and cell death. c-Jun N-terminal kinases (JNKs) are identified as members of the mitogen-activated protein kinase family and are known to phosphorylate and activate several transcription factors, including c-Jun, ATF, and Elk-1. However, the role of JNK activation in tumor promotion is not yet defined. Because previous studies have indicated that exposure of JB6 Cl 41 cells to either 12-O-tetradecanoylphorbol-13-acetate (TPA) or tumor necrosis factor-alpha (TNF-alpha) results in cell transformation, we investigated the role of JNKs in this biological process by using dominant negative JNK(1) and the cell transformation model JB6 Cl 41 cells. Incubation of Cl 41 cells with TNF-alpha led to cell transformation and activation of JNKs. Introduction of the dominant negative mutant of JNK(1) into JB6 Cl 41 cells specifically inhibited TNF-alpha-induced activation of JNKs, but not Erks and p38 kinases. Most importantly, expressing dominant negative mutant JNK(1) inhibited TNF-alpha-induced cell transformation but not TPA-induced cell transformation. Our results directly demonstrated for the first time that JNK activation is required for TNF-alpha- but not TPA-induced cell transformation.

Animals↗