Biomedical subjects

Feng Wang

Publications and source records attributed to Feng Wang.

At least 145 records · Page 8Linked to original sources

PubMed2005

[Analysis of angiogenesis associated factors of retinoblastoma cell line and tumor tissues].

OBJECTIVE: To investigate the factors regulating angiogenesis of retinoblastoma. METHODS: Cultured retinoblastoma cells from HXO-Rb-44 cell lines were inoculated subcutaneously into the leg of nude-mice. Experimental retinoblastoma was studied by immunohistochemistry staining for the expression of angiogenesis factors (VEGF-A, VEGF-C, VEGF-D and bFGF), vascular endothelial cell membrane receptor tyrosine kinases (Flt-1, Flt-4, Flk-1, Tie-2 and FGFR), transcription regulated factor, Hif-1, matrix metalloproteinase (MMP-2, MMP-7 and MMP-9) and tissue inhibitor of metalloproteinase (TIMP-1 and TIMP-2). RESULTS: There were plenty of capillaries and small vessels in the retinoblastoma. Some retinoblastoma cells expressed Hif-1 and most cells expressed VEGF at a high level, especially VEGF-D. Flt-1, Flt-4 and FGFR were found in vascular endothelial cells in the retinoblastoma. Three matrix metalloproteinases were positive and two tissue inhibitors of metalloproteinases were negative in the retinoblastoma. CONCLUSIONS: Down-regulated TIMP and up-regulated MMP and VEGF signal transduction play an important role in the occurrence of angiogenesis in the retinoblastoma. This could be considered as the target of retinoblastoma treatment.

Animals↗

PubMed2005

[Activation of Kupffer cell TLR2 signaling pathway during hepatic ischemia/reperfusion injury process in mice and it's significance].

OBJECTIVE: To study changes of TLR2 signaling pathway expression in Kupffer cells during the process of hepatic ischemia/reperfusion in a mice model and the mechanism of TLR2 signaling pathway participating in hepatic ischemia/reperfusion injury. METHODS: BALB/c mice were divided into 3 groups: sham operation (SH), ischemia/reperfusion (I/R) and GdCl3 treatment (Gd) groups. After 4 h of reperfusion, the expression of TLR2 mRNA and membrane TLR2 protein were analyzed in ischemic lobes of the livers, and in Kupffer cells isolated from ischemic lobes. The expression of NF-kappaB in ischemic lobes was also examined. Levels of endotoxin, ALT and TNFalpha were measured at the same time point. RESULTS: The expressions of TLR2 mRNA and protein in both ischemic hepatic lobes and Kupffer cells isolated from ischemic lobes were increased in the I/R group compared to those in the SH group, as well as the expression of NF-kappaB in ischemic lobes, which was down regulated by intravenous GdCl3 treatment. Levels of ALT and TNFalpha in the portal vein were higher in the I/R group than in the SH group, which also were decreased with treatment of GdCl3. The level of endotoxin in the three groups remained constant. CONCLUSION: TLR2 signaling pathway in Kupffer cells is activated during the process of hepatic ischemic/reperfusion injury. The activation of TLR2 signaling pathway in Kupffer cells may play a role in this process.

Animals↗

PubMed2005

[Treatment of ureteral calculi with ballistic lithoclast].

OBJECTIVE: To evaluate the availability of ballistic lithoclast in treatment of ureteral calculi. METHODS: Totally 625 patients with ureteral calculi were treated with ballistic lithoclast by rigid ureteroscopy. RESULTS: Totally 610 patients were treated successfully by ballistic lithoclast with a cure rate of 97.6% (90.3% in upper ureter, 96.8% in middle ureter, 100% in lower ureter). The average time of lithoclast was (5.0 +/- 2.8) minutes and the stone-free rate was 99.2%. CONCLUSION: Ballistic lithoclast combined with rigid ureteroscopy is safe and effective in treating ureteral calculi.

Adult↗

PubMed2005

[Effects of c-myc antisense oligodeoxynucleotide on the telomerase activity and the induction of apoptosis in HL-60 cells].

To investigate the effects of c-myc antisense oligodeoxynucleotide (ASODN) on the telomerase activity and the induction of apoptosis in HL-60 cells, and to explore the relationship between the telomerase activity and the expression of c-myc gene in HL-60 cells, after treatment by c-myc ASODN, the expression of c-myc was detected by RT-PCR, the apoptosis, cell cycle were detected with agarose gel electrophoresis and flow cytomety, and the telomerase activity was determined with TRAP-ELISA. The results showed that after blocking c-myc gene with ASODN for 72 hours, it is obvious that the expression of c-myc gene was inhibited. The percentage of S phase HL-60 cells decreased from 55.6% to 30%, the early apoptosis peak appeared (the percentage of apoptosis cells were 25.2%) and the DNA ladders were shown. OD(450 - 690) were 2.648 +/- 0.42, 2.324 +/- 0.36, 2.162 +/- 0.38, 1.952 +/- 0.14, 1.805 +/- 0.40, 1.616 +/- 0.41 and 2.466 +/- 0.29, respectively, as the cells were treated with 0, 1, 2, 3, 4, 5 micromol/L ASODN and 5 micromol/L SODN for 72 hours. The difference was significant when compared 3, 4, 5 micromol/L groups with 0 micromol/L ASODN group respectively (P < 0.05), but the difference was no significant when compared 1, 2 micromol/L ASODN and 5 micromol/L SODN groups with 0 micromol/L ASODN group (P > 0.05). It is concluded that the c-myc gene ASODN may induce the apoptosis of cells, inhibit cells from G(1) phase into S phase and regulate the telomerase activity down in HL-60 cells by blocking the expression of c-myc gene.

Apoptosis↗

PubMed2005

[A study of 10-23 DNAzyme inhibiting the expression of hepatitis B virus genes].

OBJECTIVES: To explore, on the cell level, the possibility of using 10-23DNAzyme, as a new genetherapy in treating hepatitis B. METHODS: Phosthorothioate 10-23DRz (DRz-S) and 10-23DRz specific to HBV pre-C/C gene ORFA2031 were designed and synthesized, and the inhibition effects of 10-23DRz-S and 10-23DRz on the expression of HBV gene in HepG2 2.2.15 cells were observed. RESULTS: The expression of HBV gene was remarkably depressed after 2.2.15 cells were transfected by DRz-S and DRz. The maximum inhibition was 93.75% and 90.26%. The inhibition effect was maintained for 96 hours, and the inhibition time of DRz-S was longer than that of DRz. The maximum inhibition of DRz-S was lower than that of DRz. The efficiency of inhibiting HBsAg and HBeAg in 2.2.15 cells transfected by DRz-S and DRz was higher than that by antisense oligonucleotides for the same target genes. It had no remarkable effect on the replication of HBV DNA and no toxicity to the 2.2.15 cells. CONCLUSION: 10-23DRz can highly block the expression of HBV gene in the 2.2.15 cell model and it can serve as a specific and effective anti-HBV gene therapeutic means.

Carcinoma, Hepatocellular↗

PubMed2005

[Tumor targeting gene transfer mediated by electroporation for growth suppression of retinoblastoma in vivo].

OBJECTIVE: To explore the effects and mechanisms of electroporation on the therapy of transplanted retinoblastoma tumor (RB) by transferring the expressive plasmids of sFlk-1 and ExTek. METHODS: The effects and mechanisms of sFlk-1 and ExTek on RB is validated both in vitro and in vivo. In vitro, pCI-sFlk-1 was transfected into HEK293 (human embryonic kidney 293) cells with DMRIE-C Reagent, and its supernatant was collected 24 h later to mix with RPMI-1640 medium as 1:1, 2:1 and 3:1. RB cells were cultured in the mixed medium and the cell growth curve were analyzed 6 days later. The suspension of 1 x 10(7) RB cells were inoculated in 40 nude mice subcutaneously. The nude mice with RB were divided into 2 groups. The experimental group was treated with transfer of pCI-sFlk-1 (15 microg) and pCI-ExTek (15 microg) by electroporation once a week, while the control group was treated with physiological saline solution. After 3 weeks' therapy, the animals were observed for one more week. During this period the tumors were measured to draw the growth curve of the tumors and to calculate the anti-tumor rate. The vessel endothelium were tagged with smooth muscle actin (SMA) by immunohistochemical methods to inspect the micro vessel density (MVD) of the tumors. Moreover, the expression of vascular endothelial growth factor (VEGF) and its receptor Flk-1 of the tumors was confirmed by immunohistochemical staining. RESULTS: sFlk-1 exhibited no inhibiting effects on the growth of RB cells in vitro, while sFlk-1 combined with ExTek restrained the growth of the transplanted tumors obviously in vivo, and the anti-growth rate is 80.04%. The MVD of the experimental group is 26.69 +/- 2.95, which is evidently lower than that of the control group (44.51 +/- 6.11). The difference between these 2 groups was statistically significant (P < 0.05). As to the expression of VEGF, there was no significant difference between these 2 groups, while the expression of Flk-1 of the experimental group was much stronger than that of the control group. CONCLUSION: Transfer the expressive plasmids of sFlk-1 and ExTek by electroporation in vivo restrained the growth of the transplanted RB tumor, and the effect is due to the inhibition of angiogenesis process.

Animals↗

PubMed2005

[Cleavage of HCV by HCV specific deoxyribozyme in vitro].

OBJECTIVE: To study the cleavage activity of specific deoxyribozyme to hepatitis C virus in vitro. METHODS: Three deoxyribozymes were designed to cleave at sites 157, 168, 173 in HCV 5'-noncoding region with the active region of 5'-GGCTAGCTACAACGA-3' respectively. Plasmid pCMV/T7-NCRC -Delta Luc was completely linearized with restriction endonuclease Xba I. HCV RNA5'-NCRC was transcribed in vitro from the linearized products and radiolabelled with [alpha-32P] UTP. Under the conditions of 37 degrees C, pH7.5, Mg2+ 10 mmol/L, the three deoxyribozymes were mixed with substrate RNA individually for 120 minutes and then the reactions were terminated. The cleavaged products were separated with 8% denaturated polyacrylamide gel electrophoresis and displayed by autoradiography. DRz3 was mixed with the substrate RNA at different Mg2+ concentrations. The cleavage efficiency was analyzed with a gel document action analyzing systems. RESULTS: Under the adopted conditions the three deoxyribozymes efficiently cleaved to the target RNA in vitro and the cleavage activity of DRz3 was increased with the increase of Mg2+ concentration. CONCLUSION: The designed deoxyribozymes can cleave 5'-NCR mRNA of HCV efficiently in vitro and it is dose-respondent to Mg2+ concentration.

DNA, Catalytic↗

PubMed2005

[Testicular injuries: report of 31 cases].

OBJECTIVE: To report 31 cases and 32 testicles of testicular injuries and summarize the experience of treatment. METHODS: Thirty-one patients suffered from testicular injuries which included 26 cases of closed injuries and 5 cases of open injuries. Nine cases were treated with expectant treatment (surgical treatment were performed in 2 out of 9 cases later) and 22 cases were treated with surgical treatment directly. RESULTS: Twenty-five patients and 26 testicles were followed up from 7 months to 9 years,which included 9 cases of expectant treatment and 16 cases of surgical treatment. There were 2 patients with orchiatrophy in expectant treatment group and surgical treatment group respectively. No patient had testicular sclerosis and chronic pain. CONCLUSION: Patients suffering from scrotal trauma or perineal trauma, might have testicular injuries simultaneously. The ultrasonic examination is preferred in these patients. Expectant treatment should be performed under the ultrasonic monitoring and some patients should be underwent operations research actively.

Adolescent↗

PubMed2005

[The role of specific ROCK inhibitor in the prevention of experimental PVR in rabbits].

OBJECTIVE: To determine the effect of Y27632, a specific inhibitor of p160 Rho-associated coiled-coil forming protein kinase (ROCK), on experimental rabbit PVR. METHODS: Cultured rabbit retinal pigment epithelial cells were used in the experiments. The effects of Y27632 on RPE alpha-SMA (smooth muscle actin) stress fiber formation were studied by immuno-fluorescent staining. An in vitro type I collagen gel contraction assay and MTT assay were used to detect the effect of Y27632 on RPE cell contractile force and proliferation. Cultured 6 th passage rabbit RPE cells were injected intravitreally to induce the PVR model and then followed injection of 50 micromol/L of Y27632. The presence of tractional retinal detachment (TRD) was assessed to evaluate the effect of this agent in vivo. Electroretinography and histological studies were performed after intravitreal injection of Y27632 into untreated eyes to evaluate toxicity. RESULTS: The results showed that Y27632 disrupted SMA stress fiber formation in the cultured RPE cells and impaired contractile force generated by RPE cells (t = 16.212, P < 0.01). Development of TRD was significantly reduced (P < 0.01) with 50 micromol/L of Y27632. No obvious histological or retinal functional damage was found in the Y27632-treated group. CONCLUSION: p160 ROCK specific inhibitor Y27632 decreased contractile force generated by RPE cells and attenuated PVR without significant side effect in rabbit. This reagent could be potential therapeutically method in the treatment of PVR.

Amides↗

PubMed2005

[Expression of somatostatin receptor reporter gene and its correlation with targeted imaging in vivo for detection of pancreas carcinoma].

OBJECTIVE: To evaluate the value of (99 m)Tc-sandostatin scintigraphy in targeted diagnosis of pancreas carcinoma and the correlation with expression of somatostatin receptor (SSTR) reporter gene in tumor tissue. METHODS: Nude mice bearing human pancreas carcinoma xenograft were established in advance. (99 m)Tc-sandostatin imaging was performed in 18 nude mice and tumor to normal tissue ratio (T/NT) was calculated. mRNA expression of SSTR1, SSTR2 and SSTR5 in tumor tissue was detected by RT-PCR. RESULTS: Out of 18 nude mice, 13 mice showed intense uptake of (99 m)Tc-sandostatin. Six hours after (99 m)Tc-sandostatin administration, the T/NT ratio was 2.53 +/- 0.84. Five mice showed negative findings, and the T/NT ratio was 1.04 +/- 0.06. Positive correlations were obtained between the T/NT ratio and the expression of SSTR1 and SSTR2 mRNA, especially SSTR2 (r = 0.807, P < 0.01). CONCLUSION: High expression of SSTR1, SSTR2 and SSTR5 mRNA were found in human pancreas tumor xenograft in nude mice, especially SSTR2. There is a significant correlation between the tumor uptake of (99 m)Tc-sandostatin and SSTR2 mRNA level. This approach may allow SSTR-targeted diagnosis and therapy of human pancreas cancer.

Animals↗

PubMed2005

[Preventing scarring in split-thickness skin donor sites with epidermal grafting].

OBJECTIVE: Introducing a new technique for preventing the scar growthing in split thickness skin donor sites using the great sheets of epidermis covering. METHODS: The donor sites of split thickness skin were grafting with the great sheets of the epidermis, of the thickness about 0.07 approximately 0.12 mm, harvested by electrical power dermatome and fixed the edges of the epidermal sheet with the verges of donor wound together using the nanoparticles-Ag-gauze stripes adding the sutures or skin stapler, dressing the wounds with the nanoparticles-Ag-gauze using the tie-over technique, left the dressing entire for a 5-day period. RESULTS: This method were used in a total of 209 donor sites of both the split-thickness skin and epidermis for 133 reconstructed sites of 118 cases from November 1999 to November 2003, and the smooth, near normal skin appearance without scarring were obtained in the split thickness skin donor sites, and the epidermal donor sites healed good enough 5 days after surgery, and skin appearance is near normal in 3 months later. CONCLUSIONS: Covering the donor sites of split thickness skin with the large sheets of epidermis is an effective and useful method for preventing the scarring in the split thickness skin donor sites.

Adolescent↗

PubMed2004

Structural basis for broad substrate specificity of earthworm fibrinolytic enzyme component A.

Earthworm fibrinolytic enzyme component A (EFE-a) possesses an S1 pocket, which is typical for an elastase-like enzyme, but it can still hydrolyze varieties of substrates, and it exhibits wide substrate specificity. Former structure studies suggested that the four-residue insertion after Val(217) might endow EFE-a with this specificity. Based on the native crystal structure at a resolution of 2.3A, we improved the native crystal structure to 1.8A and determined its complex structure with the inhibitor Meo-Suc-Ala-Ala-Pro-Val-CMK at a resolution of 1.9A. The final structures show that: (1) EFE-a possesses multisubstrate-binding sites interacting with the substrates; (2) significant conformation adjustment takes place at two loops binding to the N-terminal of the substrates, which may enhance the interaction between the enzyme and the substrates. These characteristics make the substrate-specificity of EFE-a less dependent on the property of its S1-pocket and may endow the enzyme with the ability to hydrolyze chymotrypsin-specific substrates and even trypsin-specific substrates.

Amino Acid Sequence↗

PubMed2004

Study of the interaction of proteins with curcumin and SDS and its analytical application.

It is found that protein and sodium dodecyl sulphonate (SDS) can enhance resonance light scattering (RLS) of curcumin (CU). Based on this phenomenon, a new quantitative method for protein in aqueous solution has been developed. In the BR (pH 3.5) buffer, the RLS intensity of CU-SDS system is greatly enhanced by protein. The enhanced RLS is proportional to the concentration of protein in the range of 0.00020-20.0 microgml(-1) for bovine serum albumin (BSA) and 0.00040-1.0 microgml(-1) for human serum albumin (HSA) and their detection limits are 0.16 and 0.041 ngml(-1), respectively. An actual sample is satisfactorily determined. In addition, the interaction mechanism between protein and CU-SDS is also studied by using multi-techniques such as RLS, absorption spectroscopy and fluorescence, zeta potential assay measurement.

Animals↗

PubMed2004

Reversible surface oxidation and efficient luminescence quenching in semiconductor single-wall carbon nanotubes.

We have investigated reversible single-wall carbon nanotube (SWNT) oxidation by quantitative analysis of the oxide-induced absorption bleaching and luminescence quenching at low pH. These data, in combination with DFT structure calculations, suggest that the nanotube oxide is a 1,4-endoperoxide. At low pH, the endoperoxide protonates to create a hydroperoxide carbocation, introducing a hole in the SWNT valence band. Nanotube luminescence is extremely sensitive to quenching by hole-doping, while the absorption is relatively robust.

Journal Article↗

PubMed2004

Probing electronic transitions in individual carbon nanotubes by Rayleigh scattering.

Rayleigh scattering spectra were obtained from individual single-walled carbon nanotubes with the use of a laser-generated visible and near-infrared supercontinuum. This diagnostic method is noninvasive and general for nanoscale objects. The approach permits clear identification of excited states in arbitrary metallic and semiconducting nanotubes. We analyzed spectral lineshapes in relation to the role of excitonic effects and correlated the results with Raman scattering data on individual tubes. The nanotube structure remained the same over distances of tens of micrometers. Small nanotube bundles retained distinct Rayleigh spectroscopic signatures of their component nanotubes, thus allowing the probing of nanotube-nanotube interactions.

Journal Article↗

PubMed2004

Palladium-catalyzed tandem reaction of yne-propargylic carbonates with boronic acids: a simple method for the synthesis of fused aromatic rings through allene-mediated electrocyclization.

The palladium-catalyzed tandem reactions of yne-propargylic carbonates with aryl boronic acids, 2-furyl boronic acid, and 2-thiopheneboronic acid, followed by 6pi-electrocyclization to give fused ring aromatic products such as naphthalene, benzofuran, and benzothiophene derivatives are realized. Screening of the reaction conditions revealed that the combination of [Pd(PPh3)4] in THF gave the best results in terms of reactivity and product yields in the reaction of yne-propargylic carbonates with phenylboronic acid. The reaction is sensitive toward steric hindrance when substituted phenylboronic acids are employed. However, when we take 2-furyl boronic acid as the organometallic reagent, most substrates perform very well to give benzofuran derivatives. In addition, 2-thiopheneboronic acid is also a very effective coupling reagent to give bezothiophenes in high yields. A mechanism is proposed that involves the formation of an allenylpalladium complex from Pd0 and propargylic carbonate, followed by insertion of an intramolecular triple bond and the Suzuki coupling reaction, and then electrocyclization.

Journal Article↗

PubMed2004

Green fluorescent protein as a vital elimination marker to easily screen marker-free transgenic progeny derived from plants co-transformed with a double T-DNA binary vector system.

We investigated the potential of a novel double T-DNA vector for generating marker-free transgenic plants. Co-transformation methods using a double T-DNA vector or using mixture of two Agrobacterium tumefaciens strains were compared, and showed that the double T-DNA vector method could produce marker-free transgenic tobacco (Nicotiana tabacum L.) plants more efficiently. A dual marker double T-DNA vector was then constructed by assembling the green fluorescent protein (GFP) gene mgfp5 and the neomycin phosphotransferase gene nptII into the same T-DNA. The frequency of co-transformants produced by this vector was 56.3%. Co-expression of mgfp5 and nptII was found in 28 out of 29 T1 lines, and segregation of the reporter beta-glucuronidase gene, gusA, from mgfp5 to nptII was found in 12 out of 29 T1 lines. Therefore, GFP could be used as a vital marker to improve the transformation efficiency and to easily monitor the segregation of marker genes, thus facilitating screening of marker-free progeny.

Agrobacterium tumefaciens↗

PubMed2004

Correlation of lymphocyte heat shock protein 70 levels with neurologic deficits in elderly patients with cerebral infarction.

PURPOSE: To assess the association between heat shock protein 70 (HSP70) levels and the severity of ischemic stroke in elderly patients. METHODS: We conducted a case-control study to investigate the changes in lymphocyte HSP70 levels by immunoblot in 65 elderly patients with mild (n = 22), intermediate (n = 21), or severe (n = 22) stroke, and in 34 healthy controls. We analyzed correlations between HSP70 levels and neurologic deficit scores on days 1, 15, and 30 after the onset of stroke. RESULTS: Mean (+/- SD) HSP70 levels were higher in all stroke patients compared with controls (mild stroke: 709 +/- 194 units; intermediate: 585 +/- 165 units; severe: 421 +/- 124 units; controls: 86 +/- 34 units on day 1). Patients with mild stroke had higher levels at day 1 and 15 than did patients with severe stroke. HSP70 levels decreased rapidly from days 1 to 30 in all patients, except in patients with severe stroke, in whom levels decreased slowly between days 15 and 30. There were significant negative correlations between HSP70 levels and neurologic deficit scores in patients on days 1 (r = -0.53, P < 0.001) and 15 (r = -0.54, P < 0.001), but a positive correlation on day 30 (r = 0.49, P < 0.001). CONCLUSION: These data suggest that HSP70 may be a marker for neuroprotection in the early stage of ischemic stroke and a marker for a crisis in the later stages of severe cerebral infarction. Further studies on the use of lymphocyte HSP70 levels in predicting clinical outcomes and underlying mechanisms in cerebral infarction are warranted.

Aged↗