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Biomedical subjects

Y Ma

Publications and source records attributed to Y Ma.

At least 217 records · Page 12Linked to original sources
PubMed2000

[Effects of p16 and GM-CSF combined gene therapy on immune response of tumor-bearing mice].

OBJECTIVE: To investigate the effects of p16 and GM-CSF combined gene therapy on immune response of tumor-bearing mice (Renca). METHODS: The model of renal tumor-bearing mice was constructed by subcutaneous injection of Renca cells. The tumor-bearing mice were divided into 5 groups at random three days after injection of Renca cells. Different groups of mice were given different treatments. The antitumor immune responses and the survival time of mice were tested. Histopathologic analysis of tumor tissue was done. RESULTS: Enhancement of antitumor immune responses and prolongation of survival period were observed more obviously in tumor-bearing mice after combined therapy than in those of the other four groups. CONCLUSIONS: p16 and GM-CSF combined gene therapy can enhance the antitumor immune responses of mice and inhibit the growth of pre-established renal cell carcinoma.

Adenoviridae↗
PubMed2000

[Effects of adenovirus-mediated p16 and p53 genes transfer on apoptosis and cell cycle of lung carcinoma cells].

OBJECTIVE: To explore the synergistic inhibition effect and apoptosis induction of p16 and p53 genes on lung carcinoma cells. METHODS: E1-deficient and replication-defective recombinant p16 and p53 adenoviruses were generated by liposome-mediated co-transfection of recombinant plasmid pAdCMV-p16 or pAdCMV-p53 along with pJM17 and homologous recombination in 293 packaging cell. The lung cancer cell line H358, which had a homozygous deletion of p53 gene and no expression of p16 mRNA and protein, was infected with recombinant p16 and p53 adenovirus either individually or together. RESULTS: Immunohistochemical analysis showed that recombinant adenovirus could transfer p53 gene into tumor cell with 98% efficiency. Western blot indicated that p16 and p53 proteins were expressed at a high level in infected H358 cell. Inhibition effect of p53 gene on proliferation of H358 cell was weaker than that of p16 gene, and the combined use of both genes could completely prevent the proliferation of H358 cell. In situ end-labeling and flow cytometry indicated that p16 could result in G(1) arrest of cell cycle and did not induce H358 cells to undergo apoptosis; p53 also induced apoptosis of few cells besides G(1) arrest; and the simultaneous use of p16 and p53 genes could induce marked apoptosis of H358 cells. CONCLUSION: p16 and p53 genes possess the synergistic inhibiting effect on growth of lung cancer cells and can cooperate to induce apoptosis of H358 cell. The combined application of recombinant p16 and p53 adenoviruses can be used as a new strategy for cancer gene therapy.

Adenoviridae↗
PubMed2000

[Effect of mouse p53 minigene on lung cancer cells with different 172 structures regulated by tetracycline].

OBJECTIVE: To investigate the effect of mouse 172 wild-type p53 (Arg), pseudo-wild-mutant-type p53 (Arg-->Leu) and mutant-type p53 (Arg-->His) induced by absence of tetracycline on the growth of PG cell line. METHODS: Three variant types of p53 minigene were sub-cloned by gene recombination into an expression vector which was controlled by tetracycline. Through LipofectAMINE, the vectors were transfected into p53 defective PG (248CGG-->CTT) cells, and the transfectants were screened in the selecting medium containing puromycin. Tumor suppressing effects were studied by MTT absorption, flow cytometry and Western blotting. RESULTS: Wild-type p53 and pseudo-wild-mutant-type p53 could lead cells to decrease their growth rates, arrest cell cycle and transactivation of p21(WAF1). Mutant-type p53 was defective in tumor suppression. CONCLUSION: Wild-type p53 and pseudo-wild-type p53 may inhibit cell growth and induce cell cycle arrest. Some p53 variants such as 172 Arg-->Leu can still retain the tumor suppression function of the wild-type.

Amino Acid Substitution↗
PubMed2000

[Effect of different injections of Chinese herbal medicine on stress hormones and immune cell factors in patients of type 2 diabetes mellitus complicated with acute cerebral infarction].

OBJECTIVE: To investigate the effect and clinical significance of different injections of Chinese herbal medicine on stress hormones and immune cell factors in treating patients of type 2 diabetes mellitus complicated with acute cerebral infarction. METHODS: Patients were divided into three groups, treated with Defibrase injection (DI, n = 32), Acanthopanax injection (AI, n = 20) and Ginaton injection (GI, n = 12) respectively. Parameters, including corticotropin-releasing hormone (CRH), adrenocoticortropic hormone (ACTH), cortisol (CS), tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) were determined using RIA in patients before and after treatment. The changes of parameters were analyzed and compared with those of healthy subjects for control. RESULTS: (1) Levels of all the above-mentioned parameters in all the three treated groups were higher than those in the healthy control group (P < 0.01); (2) All parameters were reduced after treatment in the three treated groups and the optimal effect was shown in the DI group (P < 0.01). CONCLUSION: The beneficial action of the three injections is closely related with the levels of stress hormones and immune cell factors, therefore, to monitor dynamically the changes of CRH, ACTH, CS, TNF alpha and IL-6 is of important significance in evaluation of therapeutic effect and elucidation of the pharmacology of Chinese herbal medicine.

Adrenocorticotropic Hormone↗
PubMed2000

[PCR amplification and cloning of virulence expression regulatory gene toxR of Vibrio cholerae].

In order to construct a genomic bivalent oral vaccine of Leishmania donovani and Vibrio cholerae, we amplified a 1.3 kb DNA fragment from 7 strains of Vibrio cholerae with primers P1 and P2. Restriction endonuclease analysis of PCR amplified products from 9 strains of Vibrio cholerae was performed by digestion with EcoR I. The results revealed an EcoR I site in the central part of toxR gene. The entire toxR gene of Vibrio cholerae Non-CT strain 7743 was amplified by PCR with primers P1 and P2, digested with endonucleases BamH I and Hind III, then was orientationally cloned into plasmid pAT153. The restriction endonuclease analysis demonstrates that the recombinant plasmid ptR4 contains a 1.3 kb toxR gene fragment.

Bacterial Proteins↗
PubMed2000

[Immune reconstitution in immunosuppressed pigs with human immune competent cells].

To reconstitute the immune system of the pig with human immune cells after destroying or suppressing it, so that the transplant immunoreactivity between human and pig could be monitored in vivo. Fifteen Chinese Neijiang pigs were divided into 3 groups. Group A (n = 5) received immunosuppression through intravenous infusion of methotrexate (MTX), myleran and cyclophosphamide (CTX). Group B received intraperitoneal injection of human bone marrow and spleen cells (HBSC) after the same treatment as group A. Group C (n = 5) received intravenous infusion of HBSC after the same treatment as group A. Blood routines and biochemical analysis were monitored. The chimerisms of human cells were supervised through immunohistochemistry of cytospin of peripheral blood from recipient pigs and flow cytometry of the same specimen and immunohistochemistry of frozen tissue sections and paraffin sections. All pigs in group A survived definitely. Group B and C survived 3 days to 54 days and 15 hours to 60 days respectively. The peripheral white blood cell count (WBCC) of group A, B and C decreased to the bottom 7 days after drug administration, about 1%-10% of the normal level. After transplantation, the WBCC of group B and C recovered more slowly than those of group A. Human cells were found in the recipient pigs of group B and C after transplantation through immunohistochemistry of peripheral blood cytospin and flow cytometry. Infiltration of human cells was found in the spleens and lungs of group C and D through immunohistochemistry. The chimerism of human cells in recipient pigs could be established by transplanting human bone marrow and spleen cells into immunosuppressed pigs. It is possible that XGVHD occurs in the recipient, which offers a novel animal model for studies on immunoreactivity of pig-to-human xenotransplantation. The proportions of human cells in peripheral blood of recipient pigs are low long after transplantation through both intraperitoneal injection and intravenous infusion.

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

[Continuous ethanol fermentation using tapioca starch by immobilized yeast cell without carrier].

A widespread interest has been noted in continuous power ethanol fermentation utilizing systems with immobilized yeast cell through self-flocculating. We studied continuous ethanol fermentation by a naturally flocculent strain of Schizosaccharomyces pombe and the performance of two-stage continuous ethanol fermentation system using suspended-bioreactors(total effective volume 1.5 L) has been established: the high biomass levels achieved allow efficient ethanol conversion(72.7 g/L, average), residual glucose(3.74 g/L) and high productivity(9.7 g/L.h) for 150 g/L glucose concentration in feed(tapioca syrup) with average 90% total conversion of substrate. The system was run steadily during a month research.

Bioreactors↗
PubMed2000

[Studies of adsorbents for hemoperfusion--preparation and in vitro studies of cross-linked agar beads entrapped Attapulgite clay].

A new method for preparation of cross-linked agar beads entrapped Attapulgite clay (CAA) is reported. Attapulgite clay was coated with agar and shaped in organic solvent, as well as cross-linked by epichlorohydrin. The products withstood autoclaving at 121 degrees C for 30 minutes and had a good adsorption ability for model compounds and medicines. The results of preliminary investigation indicate that CAA is relatively hemocompatible.

Adsorption↗
PubMed2000

[The outcome of 1268 cases of endoscopic sinus surgery].

OBJECTIVE: To evaluate the curative effect of endoscopic sinus surgery (ESS). METHODS: One thousand two hundred and sixty-eight cases with chronic sinusitis and nasal polyps undergone ESS from 1989 to 1997 were appraised with the standard criteria (Chinese ENT Association, 1997). There were 366 cases(28.9%) in type 1, 646 cases(50.9%) in type 2 and 256 cases(20.2%) in type 3. One thousand two hundred and sixty-two cases underwent ESS under intranasal local anesthesia and sedation; 182 cases underwent submucous resection of nasal septum or septoplasty. Long-term follow-up was performed at 9 to 42 months(mean = 15 months). RESULTS: The results showed that cure rate was 93.7% for type 1, 81.6% for type 2 and 68.4% for type 3. There was significant difference in cure rate among different types (P < 0.01). Complication of ESS in 1,268 cases occurred in 2.3%. CONCLUSION: ESS is efficacy and safe in the treatment of nasal polyps and chronic sinusitis. The cure result is directly related to the types of the disease.

Adult↗
PubMed2000

Polymorphism of angiotensin-converting enzyme gene and genetic susceptibility to asthma with familial aggregation.

OBJECTIVE: Angiotensin-converting enzyme (ACE) plays a key role in the metabolism of angiotensin II (AT II) and inactivation of bradykinins and tachykinins, which are potent bronchialconstrictors and mediators of inflammation asthma, and ACE is heavily expressed in the lungs. An insertion-deletion (D/I) polymorphism of ACE gene has been shown to be associated with levels of ACE. We investigate whether the polymorphism of ACE gene is associated with asthma and bronchial responsiveness. METHODS: A case-control study was carried out in 50 asthmatics, 7 families with at least 2 asthmatic individuals, and 50 healthy subjects. The insertion/deletion (I/D) polymorphism of ACE gene was amplified by polymerase chain reaction (PCR). Methacholine brocho-provocation and pulmonary function tests were performed in all asthmatics. RESULTS. There was an higher gene frequency of DD genotype of ACE gene in asthmatic subjects and families individuals compared with healthy subjects (46%, 53% vs 16%, P<0.05; odd ratio 4.98). An- higher prevalence of DD genotype of ACE was in patients with bronchial hyperresposiveness (BHR) (67% vs 33%, P<0.05; odd ratio 3.8). Accordingly, the mean values of FEV1% and FEV1/FVC were higher in asthmatics carrying non-DD alleles than patients with DD genotype (73.78% vs 56.56%, P<0.05, 79.19% vs 69.29%, P<0.05, respectively). CONCLUSION: These results suggested that DD allele of ACE genotype was significantly involved in genetic susceptibility to asthma. DD genotype of ACE might be a risk factor for the degree of airway obstruction, it could also be implicated in pathogenesis of bronchial hyperresponsiveness.

Adolescent↗
PubMed2000

[Construction of plasmids expressing hepatitis E virus antigen fragments and their combinations].

OBJECTIVE: Several different regions of the HEV antigen were expressed in Escherichia coli and their immunological characteristics were simply evaluated. METHODS: Three coding sequences of immunodominant antigenic regions in structural protein of the hepatitis E virus (ORF2.1: 6287-6403nt, ORF2.2: 6743-7126nt, ORF3: full length of ORF3) were amplified by RT-PCR from the fecal supernatants of macaques experimentally infected with HEV. These three fragments were inserted into the pThioHisC expression vector separately or fused in line by (Gly)n short arms. After identified by DNA sequence analysis, these six recombinant plasmids were transformed into Escherichia coli, and immunology characteristics of expressed antigen fragments were evaluated by Western blotting. RESULTS: All six genes were successfully expressed in Escherichia coli. Western blotting assay showed that the recombinant proteins specifically reacted with the serum antibody from hepatitis E patient in various degrees. CONCLUSION: Artificial antigen based on strung epitopes provides a promising strategy for detection and prevention of HEV infection.

Antigens, Viral↗
PubMed2000

[Expression and glycosylation of rotavirus strain SA11 VP4 protein in a recombinant adenovirus].

OBJECTIVE: A modified VP4 gene of rotavirus SA11 strain was expressed by a recombinant human adenovirus. METHODS: A whole VP4 gene was obtained with PCR and induced the signal peptide at the gene N terminal. The chimera gene was cloned into pCMV plasmid that consist of human cytomagolovirus promoter and then cloned the gene to transfer human adenovirus type 5 vector. Homologues recombinant was performed by co-transfection to 293 cell line with recombinant plasmid and viral genome using CaPO4 precipitation. RESULTS: VP4 gene is 2,362 base pair in length mutation was not found in whole VP4 gene sequence. Expressed product in recombinant adnovirus was confirmed to be specific and more antigenicity by indirect immunofluorescence assay. Both Western blot and immunoprecipitation assays showed that expressed protein molecular weight was higher than wild type VP4 protein and that modified product was corresponding to a glycosylation of VP4 protein. CONCLUSIONS: It may be a effective method to modify interested gene for enhancing stability, antigenicity and immunogenicity of expressive product.

Adenoviruses, Human↗
PubMed2000

[Effect of titanium substructure on color of porcelain-fused-to-titanium restoration].

OBJECTIVE: To study the effect of titanium substructure on color of porcelain-fused-to-metal restoration. METHODS: Standard samples of Dentsply DETREY-Carat and Tibond porcelain fused-to-metal restorations were made. Color Parameters were tested by cs-5 spectrophotometer. Statistic analysis was done and the color differences were calculated. RESULTS: Most of color parameters were found to be statistically significant at the P < or = 0.05 level at substructure layer. But no statistical significance existed after putting opaque and dentin porcelain. The values of color difference between two groups at opaque and dentin porcelain layers were all smaller than 1.5. CONCLUSIONS: Titanium substructure had no visually apparent effect on final color of porcelain-fused-to-metal restoration. There was no perceived color difference between corresponding shade of two Dentsply porcelain systems (DETREY-Carat and Tibond).

Color↗
PubMed2000

[Effect of glazing techniques on color of porcelain-fused-to-titanium restorations].

OBJECTIVE: To study the effect of various glazing techniques on color of porcelain-fused-to-titanium restorations and their surface texture. METHODS: Standard samples of Dentsply Tibond porcelain fused-to-metal restorations were made. Selfglazing and over-glazing techniques were used. Color parameters were tested by cs-5 spectrophotometer with CIE1976LAB color system before and after glazing. Statistical analysis was done and the color differences were calculated. The samples' surface structure was observed under the same background. RESULTS: No statistical significance existed in all of the color parameters between two groups before and after glazing. The values of color difference were all smaller than 1.5. The samples had the same surface structure after treated by different glazing techniques. CONCLUSIONS: Glazing techniques had no effect on final color of porcelain-fused-to-titanium restoration. No matter what kind of glazing techniques were used, the same surface structure and color would be obtained as long as the same polish way was used before glazing.

Color↗
PubMed2000

[Interference and interference-restraining in flame-emitting method].

When the flame-emitting method is used to determine certain element of alkali metal and alkaline-earth metal, some other external substances will interfere in the sample-determing. This passage put forwards some efficient ways of restraining the interference. It suggests that appropriate kinds of releasing agent should be added, and the radiant energy of flame itself should be controlled so as to find out the best way to improve the accuracy of analysing.

English Abstract↗
PubMed2000

[Experimental study on using mGTR and silicone gel tube connection to repair facial nerve defect in rabbits].

OBJECTIVE: To observe and compare the effects of using mGTR or Silicone tube to repair the defect of facial nerve. METHODS: mGTR and Silicone tube methods were performed on three groups of rabbits. Then physical and histological examination was carried out to get the results of these two repair methods. RESULTS: Both the two methods can induce regeneration of facial nerve. The mGTR was more effective and faster in repairing the nerve defect. Three months after operation, the distance of NCV between the two sides of facial nerve in mGTR group was 2.33+/-1.2 m/s, 10.21+/-1.5 m/s in Silicone tube group, and 2.16+/-1.6 m/s in autogeneous nerve transplantation group. CONCLUSION: The mGTR is more effective than Silicone tube method in repair facial nerve. mGTR has some other advantages, it is likely to be a new method of nerve repair on clinical domain.

English Abstract↗