Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 199 records · Page 11Linked to original sources

PubMed2000

Upregulation of drug sensitivity of multidrug-resistant SGC7901/VCR human gastric cancer cells by bax gene transduction.

OBJECTIVE: To investigate the role of bax in a vincristine (VCR)-induced multidrug-resistant (MDR) human gastric cancer cell line, SGC7901/VCR, in which the Bax protein expression level was significantly lower compared with that in parent cells. METHODS: A bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells by lipofectamine, and resistant clones were selected by G418. Western blotting detected Bax expression in transfectants. Tetrazolium blue (MTT) assay evaluated the differences in drug sensitivity and cell cycle changes of transfectants were analyzed using flowcytometry (FCM). RESULTS: The bax eukaryotic expression vector was constructed and transfected into SGC7901/VCR cells. Through G418 selection, resistant clones were obtained. Western blotting demonstrated that the expression of Bax protein was markedly increased in bax transduced cells. These cells were more sensitive to adriamycin (ADR) and VCR than mock vector transducted cells. Moreover, bax transfection enhanced ADR-induced apoptosis and VCR-induced G2/M phase arrest of SGC7901/VCR cells. CONCLUSION: Bax was involved in the MDR of SGC7901/VCR cells.

Antineoplastic Agents, Phytogenic↗

PubMed2000

[The variation of nasal obstruction in patients with OSAS].

OBJECTIVE: To study the variation of nasal resistance and its possible relationship to obstructive sleep apnea. METHODS: The detection of nasal resistance and polysomnography were performed in 30 normal subjects, 30 snoring patients and 60 patients with OSAS. RESULTS: The study reveal that nasal resistance of the patients with OSAS (1.06 +/- 4.25) Pa.s/ml, (2.29 +/- 9.74) Pa.s/ml or snoring (0.71 +/- 0.31) Pa.s/ml was higher than that of normal group (0.40 +/- 0.13) Pa.s/ml (P < 0.01). There was a positive correlation between nasal resistance and snoring index (r = 0.258, P < 0.01), but there was no correlation among AHI, waken intervals, and nasal resistance. CONCLUSION: Nasal resistance increased in the patients with snoring or OSAS, it may be a factor related with OSAS.

Adult↗

PubMed2000

[Clinical effect of Xinqingning combined low dose continuous gastrointestinal dialysis in treating uremia].

OBJECTIVE: To investigate the clinical effect of Xinqingning (XQN), a preparation of rhubarb, combined with low dose continuous gastrointestinal dialysis in treating uremia. METHODS: Patients of uremia were divided into three groups at random, eighteen patients in the group A were treated with 1000 ml gastrointestinal dialysate (non-absorbed mannitol solution) orally 2-3 times a day, twenty patients in the group B treated with the same therapy as that in the group A, but combined with XQN 5-10 tablets 3 times per day and 19 patients in the group C treated by orally taken coated aldehyde oxystarch 5-10 g, 3 times a day. The therapeutic course for the three groups were 11 months. The changes in clinical manifestation, renal function, nutritional condition, and electrolytes before and after treatment were observed. RESULTS: After treatment, significant improvement was revealed in aspects of uremic symptoms, quality of life, nutritional condition, serum creatinine, urea nitrogen, serum phosphate, uric acid, CO2 combining power, creatine clearance, body weight and arm muscular circumference in the group A and B, as compared with those in the group C. In comparison of the group A and B, the group B showed a lower serum triglyceride and slower progression of chronic renal failure (CRF). All the criteria were not improved in the group C and with serum creatinine raised significantly. CONCLUSION: XQN combined low dose continuous gastrointestinal dialysis therapy was effective in definitely treating uremia, it provides a new therapeutic means of non-replacement therapy for CRF with uremia.

Adult↗

PubMed2000

[Production of phage-displayed single chain variable fragments of monoclonal antibody MGb1].

OBJECTIVE: To lay a foundation for obtaining a tumor-targeting vehicle for in vivo study on diagnosis and treatment of gastric carcinoma by generating single chain variable fragments (ScFv) of monoclonal antibody MGb1 directed against the cancer. METHODS: mRNA was isolated from MGb1-producing mouse hybridoma cell line, and the variable regions of heavy and light chain cDNAs were amplified separately and assembled into ScFv DNAs with a specially constructed linker DNA by PCR. The ScFv DNAs were ligated into the phagemid vector pCANTAB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13KO7 helper phage to yield recombinant phage, which display ScFv fragments as a fusion with gene 3 protein on the tips of the phage M13. After two rounds of panning with gastric carcinoma cell line KATO III highly expressing MGb1-binding antigen, the phage clones displayed ScFv fragments of the antibody were selected by enzyme-linked immunosorbent assay (ELISA) from the enriched phages. The affinity of the positive phage clones was detected by competition ELISA. RESULTS: The VH, VL and ScFv DNAs were about 340 bp, 320 bp and 750 bp respectively. 17 phage clones displayed ScFv of MGb1 were selected from 40 enriched phage clones. 4 out of the 17 phage clones could strongly compete with the original hybridoma antibody MGb1 for binding to the antigen expressed on KATOIII cells. CONCLUSION: The phage-displayed ScFv fragments of monoclonal antibody MGb1 are successfully produced by phage antibody technology, which may be useful to widen the range of application of the antibody.

Animals↗

PubMed2000

[Mimic epitope recognized by monoclonal antibody MG7 against gastric cancer through screening phage displayed random peptide library].

OBJECTIVE: To get mimic peptide epitopes that could be recognized by a monoclonal antibody against gastric cancer named MG7 from random peptide library displayed by phage, and to provide useful information for further study of the interaction between antigen and antibody. METHODS: Through affinity enrichment and immunoscreening of two phage-displayed non-apeptide libraries constructed in pVIII with MG7 MAb separately, several positive phages were obtained. Fluorescence labeling and dot blot were carried out for further identification of their binding activities. Then, some of the positive phages were sequenced and their corresponding peptide sequence was deduced according to their DNA sequence. Finally, HLA binding prediction software was applied for HLA binding analysis. RESULTS: Based on several rounds of screening and binding activity detection, we got twelve and thirty positive phage clones respectively from two libraries. Through DNA sequencing, peptide deducing and sequence aligning analysis of the positive phages, some preserved epitope information such as PLX(0 - 2)S, SAVR, XRMX and YARN were obtained. The prediction using HLA binding analysis software showed that most of the sequenced peptide had the potentiality to bind with HLA molecules. CONCLUSION: PLX(0 - 2)S, SAVR, XRMX and YARN may be some of the motifs which could be recognized by monoclonal antibody MG7.

Antibodies, Monoclonal↗

PubMed2000

[Association between genetic polymorphism of dopamine transporter gene and susceptibility to Parkinson's disease].

OBJECTIVE: To explore the association between genetic polymorphism of dopamine transporter (DAT) gene and susceptibility to Parkinson's disease (PD). METHODS: The polymorphism of DAT 3' VNTR was analyzed in 171 PD patients and 180 unrelated healthy controls with amplification fragment length polymorphism (Amp-FLP). RESULTS: Five alleles of the DAT 3' VNTR were detected, consisting of 7, 8, 9, 10 and 11 copies of the 40 bp repeated sequence. The 10-copy allele was the most common one in both patients and controls. There were significant differences in both allelic and genotypic distributions of the DAT 3' VNTR between the patient and control groups (P = 0.016, P = 0.03, respectively; Fisher's exact test). The frequency of the 11-copy allele was significantly higher in patients (4.4%) than in controls (1.1%), with an odds ratio of 4.08 (95% confidence interval 1.25 approximately 14.7, P = 0.008). CONCLUSION: DAT 3' VNTR 11-copy allele is a genetic factor susceptible to PD in the population tested.

Adult↗

PubMed2000

[Association between cytochrome P-450 enzyme gene polymorphisms and Parkinson's disease].

OBJECTIVE: To explore the association between cytochrome P-450 enzyme gene polymorphisms and Parkinson's disease (PD). METHODS: The polymorphisms of CYP1A1 and CYP2E1 gene were analyzed in 158 PD patients and 150 unrelated healthy controls with PCR-RFLP and ASA techniques. RESULTS: (1) Of the 46 patients with early-onset PD, the frequency of the m2 allele was significantly higher than that in their matched controls, with an odds ratio of 2.459 (P < 0.005); the frequencies of the m1m2 and m2m2 genotypes were significantly higher than those in their matched controls with odds ratios of 2.99 (P < 0.01) and 6.22 (P < 0.025), respectively. In contrast, no differences were observed when the frequencies of individuals with the CYP1A1 MspI alleles or genotypes among patients with late-onset PD and their matched controls were compared (all P > 0.05). (2) Of the 46 patients with early-onset PD, the frequency of the G allele was significantly higher than that in their matched controls, with an odds ratio of 2.432 (P < 0.005); odds ratio was 6.167 in homozygotes for G allele (P < 0.01). Similarly, the frequency of the G allele was also significantly higher in late-onset PD patients than in their matched controls, with only an odds ratio of 1.649 (P < 0.01). In contrast, no differences were observed when the frequencies of individuals with the CYP1A1 exon 7 A4889G polymorphic locus genotypes among patients with late-onset PD and their matched controls were compared (P > 0.05). (3) No differences were observed when the frequencies of individuals with the CYP2E1 RsaI and PstI alleles or genotypes among patients with early- and late-onset PD and their matched controls were compared (all P > 0.05). CONCLUSIONS: Our data suggest that CYP1A1 gene polymorphisms might be a genetic susceptible factor for early-onset PD, and CYP2E1 RsaI and PstI polymorphisms might not be a genetic susceptible factor for both early- and late-onset PD in the Chinese population tested.

Adult↗

PubMed2000

[Surgical repair of postinfarction ventricular septal rupture].

OBJECTIVE: To study the characteristics of occurrence of postinfarction ventricular septal rupture (VSR) and preliminarily evaluate the proper timing of operation and its effect. METHODS: Twenty patients with postinfarction VSR were divided into two groups: surgical repair (14 patients), and conventional treatment (6 patients). Clinical data were analyzed and the 14 patients were followed up for 4 months-14 years. RESULTS: The 6 patients died within 6 hours-7 days. Of the 14 patients treated surgically, however, 4 had their ruptures closed by the technique of plication and the rest by prosthetic patches. Concomitant procedures included resection of postinfarction ventricular aneurysm in all 14 patients and coronary artery grafting bypass in 3. Five patients (35.7%) died during peri-operation, and 14.3% had residual ventricular septal defects. 2 patients died of heart failure 7 and 9 years after the operation respectively, 1 was lost to follow-up, and the rest were in good condition. CONCLUSIONS: The proper timing of operation determined by the cardiac function of patients. It is necessary to improve condition of circulation before operation. The mortality rate of emergency operation is high within 3 days after VSR, and residual VSR tends to develop in a week after the repair. Operation should be performed a week after VSR. The early operative mortality is closely related to preoperative cardiogenic shock and postoperative complications.

Adult↗

PubMed2000

[Clinical use of acellular allogenic dermis or acellular porcine dermis with split-thickness autologous skin graft in 119 cases].

OBJECTIVE: To observe the effect of acellular allogenic dermis or acellular porcine dermis together with split-thickness autologous skin graft on coverage of deep burn wound and the wound of scar excision. METHODS: Acellular allogenic dermis or acellular porcine dermis produced by our unit, with split-thickness autologous skin graft, were used in repairing various wounds in 119 cases. The take rate of various wounds was compared, and the take rate of wounds in which autologous skin from different sites was used to cover either acellular allogenic dermis or acellular porcine dermis was also compared. Histological examination and follow-up were made in some cases. RESULTS: After tangential excision, eschar excision and scar excision, the wounds were covered with either allogenic acellular dermis or porcine acellular dermis and autologous split-thickness skin. The take rate was found to be (93.4 +/- 3.4)%, (92.1 +/- 4.6)%, (94.5 +/- 3.5)%, respectively. There was no a significant difference in take rate (P > 0.05). No significant difference in take rate between the transplantation of allogenic acellular dermis with autologous split-thickness skin and transplantation of porcine acellular dermis with autologous split-thickness skin was found (P > 0.05). When autologous split-thickness skin harvested from the trunk or extremities was used, the take rate was (93.1 +/- 4.8)%, (89.0 +/- 6.2)%, respectively, whereas the take rate was only about 70% - 80% when skin harvested from the scalp was used. The take rate was only about 40% when acellular allogenic dermis and autologous micro-skin graft were used to cover the wound. Histological examination 19 months after the transplantation revealed normal structure. Collagenous fibers were orderly arranged. There was no apparent hyperplasia of collagenous fibers. Hair follicles, sweat glands and other skin appendages were not found in the healed area. Grossly, no obvious pigmentation was seen, the surface was smooth with slight wound contraction, and the consistency was flexible. CONCLUSION: Acellular allogenic split-thickness dermis or acellular porcine split-thickness dermis with autologous split-thickness dermis for coverage of deep burn wound and the wound of scar excision is an ideal material.

Adolescent↗

PubMed2000

[The effect of hyperoxic solution on acute myocardial hypoxia in scalded rabbits].

OBJECTIVE: To investigate the effects of hyperoxic solution on acute myocardial hypoxia in scalded rabbits. METHODS: Rabbits inflicted with 30% TBSA III degree scald injury and/or acute myocardial ischemia were employed as the model. Animals were randomly divided into 4 groups, i.e. scalded rabbits treated with hyperoxic solution (A), scalded rabbits treated with normal saline (B), scalded rabbits without any treatment (C(b)) and normal healthy rabbits (C(h)). The cardiac function, blood rheology, blood gas analysis and the ratio of infarction to ischemic areas were dynamically monitored. RESULTS: (1) The cardiac function of the rabbits in B group was evidently worse than that in C(h) group (P < 0.01) and A group (P < 0.05). (2) The whole blood viscosity in A, C(b) and especially B groups was obviously increased compared with that in C(h) group (P < 0.05). While the viscosity in A group was much lower than that in B group (P < 0.01), it was similar to that in C(b) group (P > 0.05). (3) The PO(2) in A group was significantly higher than that in B and C (C(b), C(h)) groups (P < 0.01). (4) The ratio of infarction to ischemic areas in A group was remarkably lower than that in B group (P < 0.01). CONCLUSION: The hyperoxic solution may exert beneficial effects on acute myocardial ischemia in scalded rabbits. The mechanism might be related to the immediate correction of hypoxia in vital organs with simultaneous lowering of blood viscosity and the establishment of myocardial collateral circulation after the infusion of hyperoxic solution.

Animals↗

PubMed2000

[The influence of hTGFbeta(1) gene transfection on the proliferation of NIH 3T3 fibroblast].

OBJECTIVE: To investigate the influence of hTGFbeta(1) ene transfection on the proliferation of in vitro cultured NIH 3T3 fibroblast. METHODS: Lipofictin mediated co-transfected method was employed to transfect hTGFbeta(1) plasmid DNA into NIH 3T3 fibroblasts of the rats. Cell growth counting method, MTT, flow cytometry (FCM) and soft agar clone forming method were adopted to examine the biology of the transfected cells. RESULTS: (1) Fibroblast growth slowed down after hTGFbeta(1) transfection, especially on 4th to 6th days after the transfection, which was accompanied by decreased synthesis of DNA as indicated by the increase of G(1) phase percentage (from 39.9% to 66.2% P < 0.05) and the decrease of S phase percentage (from 40.2% to 26.8%, P < 0.05); (2) There was no evident change of all the phases in a cell cycle in the blank load transfection group and in control group. (3) There was a good correlation between MTT and cell counting method (co-efficient 0.992) (4) The formation rate of the soft agar clone of fibroblast decreased from 1.18% to 0.55% (P < 0.05) after hTGFbeta(1) transfection. CONCLUSION: hTGFbeta(1) gene transfection could inhibit fibroblast proliferation, which might be related to the interference of TGFbeta(1) with the DNA synthesis of fibroblasts.

3T3 Cells↗

PubMed2000

[Proliferation inhibition and apoptosis induction of K562 cells by fatty acid synthase inhibitor--cerulenin].

OBJECTIVE: To investigate the effect of fatty acid synthase (FAS) inhibitor--cerulenin on K562 leukemia cells and its mechanism. METHODS: Inhibition rate of cerulenin on K562 leukemia cells was assayed by MTT method, cell apoptosis by flow cytometry (FCM) and agarose gel electrophoresis. RESULTS: When treated with 10(-9) - 10(-5) mol/L of cerulenin for 24 h, the proliferation of K562 cells was obviously inhibited with dose related effect. At the same concentrations, the inhibition rates of human skin fibroblasts were all lower than 30%. When K562 cells were treated for 12 h with 50 microg/ml and 60 microg/ml of cerulenin, the apoptosis rate revealed by FCM was 42.30% and 38.8%, respectively, and DNA agarose gel electrophoresis showed the typical DNA ladder of apoptosis. CONCLUSION: Fatty acid synthase inhibitor--cerulenin inhibits proliferation of K562 cells but not of human fibroblasts. Cerulenin mediated cytotoxity is due to apoptosis induction. Fatty acid synthase might be a potential target for anti-leukemia.

Apoptosis↗

PubMed2000

[Clinical study on treatment of infantile rotaviral enteritis with Psidium guajava L].

OBJECTIVE: To observe the clinical effect of olium Psidium guajava (PG) in treating infantile rotaviral enteritis. METHODS: Sixty-two patients of rotaviral enteritis were randomly divided into the treated group treated with PG and the control group treated with Gegen Qinlian decoction. The time for ceasing diarrhea, the content of Na+ in blood, the content of Na+ and glucose in stool, and the rate of negative conversion of human rotavirus (HRV) antigen were observed. RESULTS: The rate of recovery in 3 days of the treated group was 87.1%, significantly higher than that of the control group (58.1%, P < 0.05). The time of ceasing diarrhea of the treated group (25.1 +/- 9.5 hr) was significantly shorter than that of the control group (38.7 +/- 15.2 hr, P < 0.01). The content of Na+ and glucose in stool was reduced obviously in the treated group, while the reduction in the control group was insignificant, the treated group was superior to the control group significantly (P < 0.05). The rate of negative conversion of HRV in feces of the treated group was 87.1%, significantly better than that of the control (58.1%, P < 0.05). CONCLUSION: The treatment with PG has good curative effect on infantile rotaviral enteritis.

Adolescent↗

PubMed2000

[Distinguish of the original fungi of the Chinese traditional medicine, hongqu with gas chromatography fuzzy clustering analytical method].

OBJECTIVE: To establish a gas chromatography fuzzy clustering analytical method for classifying of origin fungi of the Chinese traditional medicine, Hongqu. METHODS: The volatile and nonvolatile components of 7 ordinary species of Monascus including M. aurantiacus Lee, etc. were analyzed by capillary gas chromatog raphy using FID: Inlet temperature 280 degrees C, detector temperature 280 degrees C, temperature program 130 degrees C, 5 min-->10 degrees C.min-1-->200 degrees C, 10 min. RESULTS: In the peak number and contents of volatile and nonvolatile components of Monascus exist obviously differences through which Monascus can be distinguished easily by the main fingerprint peaks within 20 minutes. CONCLUSION: The capillary gas chromatography fuzzy clustering analytical method is useful to the identification of Monascus fungi.

Chromatography, Gas↗

PubMed2000

[Determination of major components in liuyingwan pills by supercritical fluid extraction(SFE)].

OBJECTIVE: On the basis of SFE and CGC to establish a method for the qualitative and quantitative analysis of major components in Liuyingwan pills. METHOD: Orthogonal design and variance analysis were used to optimize the four variables (temperature, pressure, volume of modifier and static extraction time) of SFE, and the quantification was completed by CGC. RESULT: The optimized conditions are as follows: pressure 48.2 MPa, temperature 60 degrees C, 0.2 ml ethyl acetate as modifier and static extraction 10 min. The recoveries of borneol and eugenol are 101.93% (RSD 1.56%) and 98.43% (RSD 2.26%) respectively. CONCLUSION: Compared with conventional methods, SFE is rapid, convenient and accurate in determining borneol and eugenol.

Camphanes↗

PubMed2000

[Regulation effect of curcumin on blood lipids and antioxidation in hyperlipidemia rats].

The regulation effects of curcumin on lowering blood lipids and antioxidation were studied in the hyperlipoidemia model Wistar rats fed with high fat diet for 4 weeks. The hyperlipoidemia model rats were then separated into four groups: normal diet group, normal diet + curcumin (5 g/kg) group, high-fat diet group and high-fat diet + curcumin group. The rats were fed with experimental diets for another 4 weeks respectively. The results indicated that curcumin decreased the serum levels of cholesterol and triglyceride and increased the serum level of apolipoprotein A. Curcumin decreased TBA value and improved total antioxidation capability. The activities of SOD and GSH-PX in liver were enhanced. After taking normal diet for four weeks, the blood fat and cholesterol levels of the hyperlipoidemia rats recovered. But in the normal diet + curcumin group, the same results could be found in two weeks.

Animals↗

PubMed2000

[Simultaneous determination of fluoroacetamide and tetramethylendisulfotetramin with gas chromatography-mass spectrography].

Simultaneous determination of fluoroacetamide and tetramethylendisulfotetramin with gas chromatography-mass spectrography was established. The condition of separation, ways of extraction, the qualitative and quantitative determination of two compounds were discussed. The linear ranges of fluoroacetamide and tetramethylendisulfotetramin were 5-40 micrograms/ml and 0.5-20.0 micrograms/ml, respectively. The recoveries of these two compounds in different sample were 52.25%-94.30% and 61.85%-92.50%, respectively. The method was fast, sensitive and accurate.

Bridged-Ring Compounds↗

PubMed2000

[Determination of major components in Psoralea corylifolia L. by using supercritical fluid extraction (SFE)].

A method based on SFE and CGC has been developed for qualitative and quantitative analysis of major components in Psoralea corylifolia L.. The orthogonal design method and the analysis of variance are used to optimize the five variables (temperature, pressure, volume of modifier, static extraction time and CO2 dynamic extracting volume) of SFE and the optimized conditions listed as follows: temperature 70 degrees C, pressure 38.5 MPa, static extraction 1 min, dynamic extraction 7 mL and 60 microL CHCl3 as modifier. The recoveries of psoralen and isopsoralen are 96.93% (RSD 1.87%) and 98.43% (RSD 2.06%) respectively. Being compared with conventional methods, the SFE as an alternative technique for sample preparation will be most useful in the quality control of Chinese traditional medicines.

Chromatography, Gas↗