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Peng Gao

Publications and source records attributed to Peng Gao.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Construction of glucosylceramide synthase-specific siRNA expression vector and its efficiency in reversal of drug resistance in breast carcinoma cells].

OBJECTIVE: To construct a glucosylceramide synthase (GCS)-specific small interfering RNA (siRNA) expression vector and to investigate the inhibitory effect of this siRNA on GCS expression and drug resistance in breast carcinoma cells. METHODS: Two GCS gene-specific siRNAs were designed and cloned into the expression vector pSUPER to generate the plasmids pSUPER-GCS1 and pSUPER-GCS2. Human adriamycin (ADM)-resistant breast carcinoma cells of the line MCF-7/ADR and human adriamycin-sensitive breast carcinoma cells of the line MCF-7 were cultured and transfected with pSUPER-GCS1, pSUPER-GCS2, and blank vector pSUPER as controls. The expression of GCS mRNA was assayed by RT-PCR and the expression of GCS protein was observed by flow cytometry. The 50% inhibition concentration of ADM on MCF-7/ADR cells was evaluated by MTT method. Flow cytometry was performed to determine the ratio of apoptosis. RESULTS: Double enzyme digestion analysis and DNA sequencing confirmed that pSUPER-GCS1 and pSUPER-GCS2 were successfully constructed. The GCS protein positive rate of the MCF-7/ADR cells 48 hours after transfection with pSUPER-GCS1 and pSUPER-GCS2 were 8.3% +/- 1.0% and 9.2% +/- 0.8% respectively, significantly lower than that before transfection (68.3% +/- 0.6%), with a inhibition rate of 89.4% and 88.5% respectively (both P < 0.01). Forty-eight hours after transfection with pSUPER-GCS1 and pSUPER-GCS2, the relative reversal rates of sensitivity to ADM of the MCF-7/ADR cells were 93.7% and 91.6%. Flow cytometry showed that the apoptotic rate of the MCF-7/ADR cells was 0.80 +/- 0.06 before transfection, 15.38 +/- 1.16 after transfection with pSUPER-GCS1 and 13.92 +/- 1.73 after transfection with pSUPER-GCS2 (both P < 0.05), and was 0.87 +/- 0.12 in the cells transfected with blank vector (P > 0.05). CONCLUSION: A GCS-specific small interfering RNA expression vector has been constructed successfully that suppresses the GCS expression and reverses the multidrug resistance in breast carcinoma cells by increasing the ratio of apoptosis in drug-resistant cells.

Antibiotics, Antineoplastic↗
PubMed2005

[Expression of mucin 1 and tumor invasiveness in breast carcinoma].

OBJECTIVE: To study the relationship of abnormal expression of mucin 1 with the invasiveness of breast carcinoma cells. METHODS: Immunohistochemistry was used to detect the protein expression of mucin 1 in 5 specimens of juxta-cancerous normal tissues, 20 specimens of benign breast tumors, 35 specimens of early breast carcinoma, 22 specimens of infiltrating cancerous tissues, and 20 specimens of lymph node foci with metastatic breast carcinoma. Human breast cancer cells of the line MCF-7 were cultured and transfected with antisense oligodeoxynucleotide (ASODN) of mucin 1. The mucin 1 mRNA expression in the cells was detected by RT-PCR and the protein expression of mucin 1 in the cells was detected by flow cytometry. The cell invasiveness was detected by Matrigel invasion assays. RESULTS: Top membrane positive expression of mucin 1 was observed in the normal breast tissues and breast benign tumors and whole membrane positive expression of mucin 1 was observed in the 30 of the 35 specimens of early breast carcinoma, 18 of the 22 specimens of breast infiltrating carcinoma, and 17 of the 20 specimens of lymph node metastatic tissues. The mRNA and protein expressions of mucin 1 in the breast carcinoma cells treated with ASODN of mucin 1 were significantly decreased (both P < 0.05). The number of invasive cells decreased significantly in the cell treated with ASODN of mucin 1 in comparison with those treated with sense nucleotide (P < 0.05). CONCLUSION: The abnormal distribution of mucin 1 contributes to the invasiveness of carcinoma cells and may not make difference in the lymphogenous metastasis of the carcinoma. The invasiveness of breast carcinoma cells can be inhibited by the ASODN complementary to the start site of mucin1 mRNA.

Biomarkers, Tumor↗
PubMed2005

Safety and immunogenicity of adenovirus-vectored nasal and epicutaneous influenza vaccines in humans.

The increasing number and density of the human population, the emergence of lethal influenza strains, and the potential use of designer influenza virus as a bioweapon, collectively highlight a critical need for more rapid production of influenza vaccines and less invasive means of delivery. We have developed a nonreplicative adenovirus-vectored influenza vaccine that can be produced without the prerequisite of growing influenza virus. This new class of vaccines can be administered as a nasal spray or skin patch by personnel without medical training. We report here that adenovirus-vectored nasal and epicutaneous influenza vaccines were well tolerated by human volunteers. The nasal vaccine was more potent than its epicutaneous counterpart under the adjuvant-free experimental condition. These results provide the foundation for further human testing of needleless vectored vaccines as promising alternatives to current vaccines.

Adenoviridae↗
PubMed2005

Rapid identification of pathogenic bacteria by capillary electrophoretic analysis of rRNA genes.

Molecular diagnosis is playing an increasingly important role in the rapid detection and identification of pathogenic organisms in clinical samples. The genetic variation of ribosomal genes in bacteria offers an alternative to culturing for the detection and identification of these organisms. Here 16S rRNA and 16S-23S rRNA spacer region genes were chosen as the amplified targets for single-strand conformation polymorphism (SSCP) and restriction fragment length polymorphism (RFLP) capillary electrophoresis analysis and bacterial identification. The multiple fluorescence based SSCP method for the 16S rRNA gene and the RFLP method for the 16S-23S rRNA spacer region gene were developed and applied to the identification of pathogenic bacteria in clinical samples, in which home-made short-chained linear polyacrylamide (LPA) was used as a sieving matrix; a higher sieving capability and shorter analysis time were achieved than with a commercial sieving matrix because of the simplified template preparation procedure. A set of 270 pathogenic bacteria representing 34 species in 14 genera were analyzed, and a total of 34 unique SSCP patterns representing 34 different pathogenic bacterial species were determined. Based on the use of machine code to represent peak patterns developed in this paper, the identification of bacterial species becomes much easier.

Bacteria↗
PubMed2005

Identification of phospholipid structures in human blood by direct-injection quadrupole-linear ion-trap mass spectrometry.

Direct-injection electrospray ionization mass spectrometry in combination with information-dependent data acquisition (IDA), using a triple-quadrupole/linear ion trap combination, allows high-throughput qualitative analysis of complex phospholipid species from child whole blood. In the IDA experiments, scans to detect specific head groups (precursor ion or neutral loss scans) were used as survey scans to detect phospholipid classes. An enhanced resolution scan was then used to confirm the mass assignments, and the enhanced product ion scan was implemented as a dependent scan to determine the composition of each phospholipid class. These survey and dependent scans were performed sequentially and repeated for the entire duration of analysis, thus providing the maximum information from a single injection. In this way, 50 different phospholipids belonging to the phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylcholine and sphingomyelin classes were identified in child whole blood.

Child↗
PubMed2005

Overexpression of extracellular superoxide dismutase (EC-SOD) in mouse skin plays a protective role in DMBA/TPA-induced tumor formation.

Extracellular superoxide dismutase (EC-SOD, EC 1.15.1.1) is a major antioxidant enzyme that is located in the extracellular matrix and on the cell surface. EC-SOD protects against cell and tissue damage initiated by extracellular-produced reactive oxygen species (ROS). We investigated a major role of EC-SOD in the development of tumor formation. In this study, we reported that skin-specific overexpressed EC-SOD transgenic mice showed half the number of tumors compared with the nontransgenic mice in the dimethylbenzanthracene (DMBA)-initiated and a 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted two-stage skin carcinogenesis model. This model showed a significant increase of the epidermal cell proliferation in the nontransgenic mice, but the proliferative response in the transgenic mice was delayed. The 8-hydroxy-2'-deoxyguanosine (8OH-dG) detection assay showed that the oxidative DNA damage was significantly higher in the nontransgenic mice than in the transgenic mice after TPA treatments. Overall, EC-SOD overexpression inhibited the TPA-induced cell proliferation and DNA damage, and reduced the subsequent formation of tumors. Our data suggest that EC-SOD plays a protective role in DMBA/TPA-induced skin carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2005

[The relationship of abnormal expression of cell glucoprotein with recurrence of pleomorphic adenoma in salivary gland].

OBJECTIVE: To study the relationship of expression of mucin 1 and E-cadherin with recurrence of pleomorphic adenoma in salivary gland, and to investigate the signal to predict the recurrence potential of the tumor. METHODS: ; The capsule of tumor was observed by microscope. The expression of mucin 1 and E-cadherin in 33 cases of primary adenoma, 12 cases of recurrent pleomorphic adenomas and 7 cases of malignant pleomorphic adenomas were detected by immunohistochemistry. RESULTS: There was no significant difference about the status of capsule and the positive rate of mucin 1 expression between primary and recurrent pleomorphic adenoma (P > 0.05). The abnormal distribution of mucin 1 expression was observed in recurrent pleomorphic adenoma (6/8), which was characterized by the positive staining of the whole cytomembrane. On the other hand, positive staining of the primary pleomorphic adenoma was observed on the top of the membrane (19/21). The difference was statistically significant (P < 0.05). The staining pattern in malignant pleomorphic adenoma was similar with the recurrent ones except higher ratio of positive expression. No significant different was observed among the three kind of tumors on the expression rate of E-cadherin (P > 0.05). CONCLUSION: The status of capsule didn't have much actual usage in predicting the recurrence of pleomorphic adenoma. There was no significant relationship between the expression of E-cd and the recurrence of the tumor. The abnormal distribution of mucin 1 expression contributes to the invasiveness of the tumor and can be used as the predictive signal for recurrence of pleomorphic adenoma.

Adenocarcinoma↗
PubMed2005

[A preliminary study of the homing capacity of allograft mesenchymal stem cells to rat liver].

OBJECTIVE: To study the homing capacity of allograft mesenchymal stem cells (MSCs) transfected with a green fluorescent protein (GFP) retroviral construct to the liver of rats. METHODS: MSCs were obtained from rat bone marrow and cultured in vitro in conditional DMEM medium supplemented with 10% fetal bovine serum. The MSCs were identified by the monoclonal antibodies of CD29, CD44, CD34, CD45, CD90, SH-2 and SH-3 followed by transfection with a GFP retroviral vector. After ex vivo expansion, the transfected MSCs were infused through the tail vein or portal veins of rats, some of which were subjected to treatment with carbon tetrachloride (CCl(4)) to induce centrolobular liver necrosis. On days 3 and 7 after transplantation, the liver was removed from each recipient and evaluated for the presence of GFP transgene in purified genomic DNA using sensitive real-time PCR. RESULTS: All the rats receiving GFP-labeled MSCs survived until the study had been completed. GFP transgene in purified genomic DNA were detected in the livers of all the rats with GFP-labeled MSC infusion by sensitive real-time PCR. DNA copy numbers of GFP in the liver were higher in rats with CCl(4) treatment than in those without the treatment. Infusion of the MSCs through the tail vein or the portal vein did not produce significant difference in the mean DNA copy number in the liver of CCl(4)-treated rats. In rats without CCl(4) treatment, the sites of MSC infusion, e.g. through the tail vein or the portal vein, produced significant difference in MSC homing to the liver, which was also related to the passage of time after MSC infusion. CONCLUSION: In rats with liver injuries induced CCl(4), the timing and number of MSCs homing to the liver might be closely related to the presence of liver injury, but not to the site of MSC infusion, e.g. through the tail vein or the portal vein. MSCs possess homing capacity to the liver in normal recipient rats, and number of homed MSCs is related to the site of infusion and post-transplantation time.

Animals↗
PubMed2005

[Comparison of isolation, preparation and culture methods of rat kidney cells].

OBJECTIVE: To compare the isolation effects and yields of rat kidney cells by three different digestion methods (collagenase, trypsinase, and the two step digestion method), the yields, proliferation rate, and LDH leakage in two different media (MEM and RPMI1640 media) in rats in two different ages (suckling and adult) . METHODS: The renal cortex from the suckling and the adult rat group was digested by three different methods, respectively, and the suspension was separately cultured in MEM and RPMI1640 media. After 48 hours, the cells were digested and counted to calculate the yields, and the proliferation rate between 24h and 48h was examined by MTT examination, and the leakage of LDH in the media was measured by biochemical analyzer every day for 7 days. RESULTS: The yields of kidney cells by collagenase and the two-step method were significantly higher than by trypsinase method (P < 0.01), the suckling group were significantly higher than the adult group. The isolation effect of the two-step method was better than the collagenase method. The yields, proliferation rate, and LDH leakage of cells in MEM and RPMI1640 media had no significant difference. CONCLUSION: The two-step digestion method was the most appropriate method for the preparation of kidney cells. Both MEM and RPMI1640 media were suitable for the culture of kidney cells. The suckling rat was proper than the adult for kidney cell preparation.

Animals↗
PubMed2004

Alteration of cyclin D1 in gastric carcinoma and its clinicopathologic significance.

AIM: To detect the genetic alteration and abnormal expression of cyclin D1 in gastric carcinoma and investigate its clinicopathologic significance in advanced gastric carcinoma. METHODS: Proteins of cyclin D1 were detected by immunohistochemistry in 42 cases of advanced gastric carcinoma with their follow-up data available, 27 cases of early stage carcinoma, 21 cases of gastric adenoma, 22 cases of hyperplastic polyp and 20 cases of normal mucosa adjacent to adenocarcinomas. Genetic alteration of cyclin D1 was detected by Southern blot and expression of cyclin D1 mRNA was detected by PT-PCR in 42 cases of advanced gastric carcinoma. RESULTS: Cyclin D1 protein was not expressed in normal mucosa, hyperplastic polyp and gastric adenoma, while it was only positively expressed in gastric carcinoma. The expression rate of cyclin D1 protein in early stage gastric carcinoma, advanced gastric carcinoma and lymph node metastasis was 48.1%, 47.4% and 50.0%, respectively. The amplification of cyclin D1 gene was detected in 16.6% of advanced gastric carcinomas. The overexpression of cyclin D1 mRNA was detected in 40.5% of the samples. There was no significant correlation between cyclin D1 protein expression and age, lymph-node metastasis and histological grading in patients with advanced gastric carcinoma (chi2 = 0.038, 0.059, 0.241, P>0.05). Significant correlation was observed between the expression of cyclin D1 protein and the 5-year survival rate (chi2 = 3.92, P<0.05). CONCLUSION: Detection of cyclin D1 protein by immunohistochemistry may be useful in the diagnosis of early gastric carcinomas. Patients with positive expression of cyclin D1 protein tend to have a worse prognosis.

Adenocarcinoma↗
PubMed2004

[Reversal of multidrug resistance of MCF-7/ADR in nude mice by grape seed polyphenol].

OBJECTIVE: To study the reversing effect of Grape seed polyphenol (GSP) on multidrug resistance of MCF-7/ADR cell in vivo. METHODS: The transplantable breast carcinoma cell line MCF-7/ADR model was established in BALB/C-nu/nu mice by subcutaneous implantation. Flow cytometry (FCM) was used to investigate the changes of Pgp expression and apoptosis rate after different drug treatment. RESULTS: GSP has some effect on inhibition of tumor growth (the rate of inhibition was 18.35%), and combined with adriamycin can significantly inhibit tumor growth in nude mice, 20 mg/kg GSP can effectively reverse the resistance of MCF-7/ADR cells to ADR in vivo, and the rate of inhibition was 54.64%. FCM results showed that the expression of Pgp was significantly decreased (32.03 +/- 2.09) After administration of GSP and ADR, there was distinct difference between it and control (55.13 +/- 2.12). The mean rate of apoptosis was 15.12% +/- 1.04%, and was significantly increased compared with control (9.07% +/- 0.43%), P < 0.05. CONCLUSION: GSP can effectively reversed the resistance of MCF-7/ADR cells in nude mice, the mechanism may be correlated with inhibition of Pgp expression and apoptosis.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Folic acid supplementation enhances repair of the adult central nervous system.

Folic acid supplementation has proved to be extremely effective in reducing the occurrence of neural tube defects (NTDs) and other congenital abnormalities in humans, suggesting that folic acid can modulate key mechanisms for growth and differentiation in the central nervous system (CNS). To prevent NTDs, however, supplemental folate must be provided early in gestation. This suggests that the ability of folic acid to activate growth and differentiation mechanisms may be confined to the early embryonic period. Here, we show that folic acid can enhance growth and repair mechanisms even in the adult CNS. Using lesion models of CNS injury, we found that intraperitoneal treatment of adult rats with folic acid significantly improves the regrowth of sensory spinal axons into a grafted segment of peripheral nerve in vivo. Regrowth of retinal ganglion cell (RGC) axons into a similar graft also was enhanced, although to a smaller extent than spinal axons. Furthermore, folic acid supplementation enhances neurological recovery from a spinal cord contusion injury, showing its potential clinical impact. The results show that the effects of folic acid supplementation on CNS growth processes are not restricted to the embryonic period, but can also be effective for enhancing growth, repair, and recovery in the injured adult CNS.

Animals↗
PubMed2004

Isolation and analysis of water stress induced genes in maize seedlings by subtractive PCR and cDNA macroarray.

In order to identify genes induced during the water stress response in maize (Zea mays) seedlings, suppression subtractive hybridization (SSH) was performed using mixed cDNAs prepared from maize seedlings treated with 20% PEG as testers and cDNAs from unstressed maize seedlings as drivers. A forward subtractive cDNA library was constructed, from which 960 recombinant colonies were picked and amplified. Through differential screening of the subtractive cDNA library, 533 clones were identified as water stress induced. After sequencing, 190 unique expressed sequence tags (ESTs) were obtained by clustering and blast analysis, which included transcripts that had previously been reported as responsive to stress as well as some functionally unknown transcripts. The ESTs with significant protein homology were sorted into 13 functional categories. A cDNA marcoarray containing the 190 unique ESTs was used to analyze their expression profiles in maize seedling during both PEG treatment and natural drought. The results indicated that 67 ESTs in leaves and 113 ESTs in roots were significantly up-regulated by PEG-stress. 123 ESTs were found to be up-regulated for at least one time-course point in either maize leaves or roots. Correspondingly, 163 ESTs were significantly up-regulated by drought stress. Results from the hierarchical cluster analysis suggest that the leaves and roots of maize seedlings had different expression profiles after PEG treatment and that there was a lot of overlap between PEG- and drought-stress induced up-regulated transcripts. A set of transcripts has been identified, which have significantly increased expression and probably involved in water stress signaling pathway based on data analysis.

Cluster Analysis↗
PubMed2004

Expression of a modified Cry1Ie gene in E. coli and in transgenic tobacco confers resistance to corn borer.

The wild-type Cry1Ie gene from Bacillus thuringiensis was modified for its efficient expression in transgenic plants. Modified Cry1Ie gene (designated as Cry1Iem) was cloned into prokaryotic expression vector pET28b and its expression in E. coli was confirmed by SDS-PAGE analysis. Bioassays using crude expression products in E. coli revealed that Cry1Iem protein had a similar toxicity to corn borer as wild-type Cry1Ie. Cry1Iem gene was then inserted downstream of the maize ubiquitin-1 promoter in plant expression vector p3301. Transgenic tobacco plants carrying Cry1Iem showed insecticidal activity against corn borer.

Animals↗
PubMed2004

[Reversal of multidrug resistance of tumor cells by anti-mdr1 ribozyme].

OBJECTIVE: To stably reverse the multidrug resistance (MDR) of breast carcinoma cells in vitro. METHODS: Two anti-mdr-1 ribozyme plasmids, RZ196 and RZ179, were constructed with EGFP as reporter gene and transfected into drug-resistant breast carcinoma cells in vitro. The expression of EGFP was observed by laser confocal microscopy. Flow cytometry, RT-PCR and Rhodamine123 efflux assay were used to detect P-glyco protein (p-gp) and mdr-1 mRNA. RESULTS: After transfection with RZ196 and RZ179, the mdr-1 indices were reduced from 2.20 to 0.76 and 1.40, the expression rates of p-gp were reduced from 55.0% to 4.6% and 18.2%, the fluorescence intensity increased from 22.0% to 46.2% and 70.1%, TCL reduced from 75% to 28% and 43% respectively. In addition, the expression of ribozyme plasmid in tumor cells was stable under G418 selection. After two months, the mdr-1 indices remained at 0.81 and 1.47 in the cells transfected RZ196 and RZ179 respectively. The expression rates of p-gp were 5.2% and 19.5% and the Rh123 fluorescence intensity was 51.4% and 71.6% respectively. CONCLUSIONS: Both anti-mdr-1 ribozyme RZ196 and RZ179 can stably reverse MDR phenotype of breast carcinoma cells in vitro. RZ196 construct appears to be more effective.

ATP Binding Cassette Transporter, Subfamily B, Mem↗