Biomedical subjects
Publications and source records attributed to Bo Tang.
Highly luminescent water-soluble CdTe nanowires synthesized in one step were used to detect copper(II) selectively below 0.078 microM in the presence of other physiologically relevant cations.
A surfactant-free route was successfully established to synthesize CeO2 single-crystalline nanowires using H2O2 as oxidizer and template agent.
A strong and stable room temperature phosphorescence (RTP) signal (lambda(ex)/lambda(em) = 298/481 nm) resulting from a 1:1:1 beta-cyclodextrin (beta-CD)/thiabendazole (TBZ)/triton X-100 (TX-100) supramolecular ternary inclusion complex was induced by KI as a heavy atom perturber. Based on the heavy-atom induced RTP, a new phosphorescence method for TBZ determination was established. The analytical curve of TBZ gave a linear range of 20-820 ng mL(-1) with a detection limit and relative standard deviation of 2.1 ng mL(-1) and 1.9%, respectively. The interference of 46 coexisting substances was studied. Compared with the method using a chemical oxygen scavenger, this method is simpler as deoxygenation of the solution is not required. The detection limit and the heavy-atom concentration of the proposed method were decreased about 8 and 4 times, respectively. The lifetime of the phosphorescence was prolonged 9 times and the pH range was greatly broadened. The proposed method has been successfully applied to the determination of TBZ in tap water, lake water and pineapples.
Ultralong and single-crystalline Cd(OH)(2) nanowires were fabricated by a hydrothermal method using alkali salts as mineralizers. The morphology and size of the final products strongly depend on the effects of the alkali salts (e.g., KCl, KNO(3), and K(2)SO(4) or NaCl, NaNO(3), and Na(2)SO(4)). When the salt is absent, only nanoparticles are observed in TEM images of the products. The 1D nanostructure growth method presented herein offers an excellent tool for the design of other advanced materials with anisotropic properties. In addition, the Cd(OH)(2) nanowires might act as a template or precursor that is potentially converted into 1D cadmium oxide through dehydration or into 1D nanostructures of other functional materials (e.g., CdS, CdSe).
This paper presents a novel spectrofluorometric method using the novel fluorescent probe 2-(2-pyridyl)benzothiazoline for the determination of superoxide dismutase (SOD) activity. The fluorescent probe was synthesized in house and fully characterized by elemental analysis and by IR and (1)H NMR spectra. It could specially identify and trap superoxide anion radicals (O2(.-)), and then was oxidized by O2(.-) to form a strong fluorescence product. On the basis of this reaction, the spectrofluorometric method was proposed and successfully used to determine SOD activity. The proposed method has a better selectivity in the determination of reactive oxygen species, because the probe can be oxidized to afford a highly fluorescent product only by O2(.-) excluding hydrogen peroxide and hydroxyl radical. As a kind of simple, rapid, precise, and sensitive technique, it could avoid the errors caused by detection time and was applied to the measurement of SOD activity in scallion genus foods with satisfactory results.
The supramolecular interaction of dequalinium chloride (DQC) and beta-cyclodextrin has been studied by flow injection spectrofluorimetry. The results showed that beta-CD reacted with DQC to form a 1:1 host:guest complex with an apparent association constant of 4.99 x 10(2) L mol(-1). Based on the enhancement of the fluorescence intensity of DQC, a flow injection spectrofluorometric method for the determination of DQC in bulk aqueous solution in the presence of beta-CD was developed. The linear range was 0.0412-30.00 microg mL(-1). The detection limit was 12.3 ng mL(-1) with a sampling rate of 80 h(-1). There was no interference from the excipients normally used in tablets and serum compositions. The proposed method was successfully applied to the determination of DQC in tablets and serum.
A flow injection (FI) kinetic spectrofluorimetric method is described for the determination of osmium(IV) and the possible mechanism of catalytic reaction is discussed. The method is based on the fluorescence enhancing reaction of o-vanillin furfuralhydrazone (OVFH) with potassium bromate, which is catalyzed by Os(IV) in water medium at pH 6.10 and 45 degrees C. OVFH is newly synthesized and its ionization, IR and elemental analysis are established. Under these experimental conditions, the oxidized product of OVFH has excitation and emission maxima at 337 and 490 nm, respectively. The linear range of this method is 0-600 ng ml(-1) with the R.S.D. of 1.2%. The detection limit is 1.0 ng ml(-1) of Os(IV). A high analysis rate of 24 samples h(-1) is obtained by the FI method. The proposed method is applied successfully to determine Os(IV) in synthetic mixture and mineral samples, and the results are well consistent with the standard values.
A method is developed for the determination of nine organophosphorus pesticide residues in cereals and kidney beans by capillary gas chromatography with flame-photometric detection. In this method, dichloromethane is used for clean-up after liquid-liquid extraction. It is shown that good separations are obtained using a fused-silica capillary column (DB-1701) by the optimized temperature program. In the spiked levels of 0.012-0.43 mg/kg, the recoveries are from 83.7% to 107%, with the relative standard deviation between 3.2% and 13% and limits of detection from 8.2 to 15 microg/kg. The method is rapid, sensitive, and practical.
OBJECTIVE: To explore the effect of von Hippel-Lindau(VHL) gene on growth of EL-4 solid tumors in vivo. METHODS: C57BL/6 mice model of solid tumors was established by subcutaneous injection of EL-4 lymphoma cells. Mice were randomly divided into two groups as treatment group (n=6) and control group (n=6) when tumor diameter increased to 0.1 cm and 0.4 cm respectively. Plasmid pcDNA3-VHL was injected into solid tumor in treatment group, empty pcDNA3 vector in control group. The growth of tumor was observed. Immunohistochemistry and Western blot analysis were used to examine the transgenic expression of VHL, hypoxia inducible factor-1alpha (HIF)-1alpha, bcl-2 and VEGF. Microvessel density (MVD) and apoptosis index (AI) of tumors were also detected. RESULTS: VHL gene transfer eradicated tumors with small size (0.1 cm diameter), but it only retarded the growth of large tumors (0.4 cm diameter). VHL was overexpressed, the expression levels of VEGF, HIF-1alpha and bcl-2 were reduced in treatment group compared with those in the control group. The level of MVD was significantly lower in treatment group (P< 0.05), but AI was higher in treatment group compared with those in the control group (P< 0.01). CONCLUSION: VHL gene therapy can inhibit the growth of EL-4 solid tumor in vivo.
OBJECTIVE: To detect the 5'CpG island methylation of estrogen receptor (ER) alpha gene promotor region in ER alpha-negative human breast cancer cell lines (MDA-MB-231 and MDA-MB-435) and breast cancer tissues; and to investigate the possibility of hydralazine in restoring the expression of ER alpha gene through demethylation. METHODS: The CpG island methylation status of ER alpha gene promotor region-A, B and C in ER alpha-negative human breast cancer cell lines (MDA-MB-231 and MDA-MB-435) and 20 cases of breast cancer tissues were analyzed using methylation-specific polymerase chain reaction (MSP). The mRNA expression profile of ER alpha isoforms (ERalpha-A, ERalpha-B and ERalpha-C) and coding region in ER alpha gene were analyzed by using RT-PCR, after hydralazine treatment. RESULTS: In the two cell lines studied, CpG island was methylated in ERalpha-A and ERalpha-B but not ERalpha-C. Among them, methylation of CpG island in ERalpha-A was obtained in 13 breast tumor cases; methylation of ERalpha-B seen in 10 tumor cases; methylation of both ERalpha-A and ERalpha-B seen in 9 cases; and methylation of ERalpha-C was obtained in only 1 case. The positivity rates were 65%, 50%, 45% and 5% respectively. CONCLUSIONS: The ER alpha gene non-expression in breast cancer is probably associated with CpG island methylation in ER alpha gene promotor region A and B, and the level of methylation is enhanced as advance of tumors in clinical stage. Hydralazine, served as a demethylating agent enables to restore the expression of ER alpha gene.
This paper presents an automatic spectrofluorimetric method (flow injection spectrofluorimetry) using a novel fluorescent probe named H. Py. Bzt (2-(2-pyridil)-benzothiazoline) for determining superoxide dismutase (SOD) activity. The fluorescent probe was synthesized in house and fully characterized by elemental analysis and by infrared and (1)H nuclear magnetic resonance spectra. It could specially identify and trap O(2)(*-) and was oxidized by O(2)(*-) to form a strong fluorescence product. Based on this reaction, the flow injection spectrofluorimetric method was proposed and successfully used to determine SOD activity. The proposed method has a better selectivity in the determination of reactive oxygen species because the probe can be oxidized only by O(2)(*-) excluding H(2)O(2). As a kind of simple, rapid, precise, sensitive and automatic technique, it was applied to measurement of SOD activity in scallion, garlic, and onion with satisfactory results.
The present study examined effects of genetic manipulation and serum starvation on in vitro developmental potential of bovine somatic cell nuclear transfer (SCNT) embryos and vitrification on in vivo developmental competence of transgenic SCNT blastocysts. Fetal oviduct epithelial cells (FOECs) were isolated from the oviduct of a Day 147 bovine fetus and transfected with a plasmid (pCE-EGFP-IRES-NEO) containing the enhanced green fluorescent protein (EGFP) and neomycin-resistant (Neor) genes. There were no significant differences (P > 0.05) in cleavage rates or development rates to the blastocyst stage for SCNT embryos derived from FOECs (72.5 and 47.8%, respectively) or transfected FOECs (TFOECs, 73.8 and 47.7%, respectively); nor from serum-fed (73.6 and 47.2%, respectively) or serum-starved (72.7 and 48.3%, respectively) cells. Seventeen of Day 7 GFP-embryos (eight fresh blastocysts and nine vitrified/thawed blastocysts ) were transferred to recipients with one embryo per recipient. Two (25%) recipients were confirmed pregnant at Day 60 in fresh blastocysts group, and three recipients (33%) were confirmed pregnant at Day 60 in vitrified/thawed blastocysts group. Two healthy calves (25%) were obtained from fresh blastocysts and one (11%) from vitrified/thawed blastocysts. Microsatellite analysis confirmed that the three clones were genetically identical to the donor cells. Moreover, PCR and Southern blot demonstrated integration of transgene in genomic DNA of all three cloned calves. Expression of GFP in skin biopsies isolated from transgenic cloned calves and fibroblasts derived from the skin biopsies revealed the activity of EGFP gene, and G418 resistance in vitro of these fibroblasts confirmed the activity of Neor gene. Our results show that genetic manipulation and serum starvation of donor cells (FOECs) do not affect in vitro developmental competence of bovine SCNT embryos, and vitrified transgenic SCNT blastocysts can develop to term successfully.
A novel host inclusion complex of cross-linking-polymeric-beta-cyclodextrin-o-vanillin furfuralhydrazone (beta-CDP-OVFH) was synthesized and characterized with IR and 1H NMR spectra to confirm its structure. The coordination reaction of the host reagent with Cd(2+) was studied and the optimum reacting conditions were observed carefully. A highly selective and sensitive spectrofluorimetric determination of trace amount of cadmium was proposed based on the reaction of Cd(2+) with beta-CDP-OVFH in ammonia water-ammonium acetate buffer medium of pH = 11.0. The molar ratio of beta-CDP-OVFH to Cd(2+) was 1:1. The maximum excitation and emission wavelengths were 393 and 494 nm, respectively. The linear range of this method was from 3.0 to 500 microg l(-1) with a detection limit of 0.80 microg l(-1). The effect of interferences in the determination of cadmium was investigated and the results showed that the host reagent had quite high capacity of identifying Cd(2+). The proposed method was successfully applied to the determination of trace amount of Cd(2+) in mussel and tea samples.
Collagen-induced arthritis (CIA) is an animal model of human rheumatoid arthritis that can be induced in susceptible mice by immunization with type II collagen (CII) or with collagen fragments, including cyanogen bromide (CB) peptides. One susceptible mouse strain, B10.RIII (I-Ar), has previously been found to respond to two major T-cell determinants, namely CII 610-618 (GPAGTAGAR) within CB10 and CII 445-453 (GPAGPAGER) within CB8. Although CB10 contains the immunodominant determinant, it is not arthritogenic. Using recombinant techniques, the determinant within CB10 was mutated to rCB10(T614P,A617E), generating a recombinant CB10 that in effect contained the arthritogenic epitope. When used for immunization, rCB10(T614P,A617E) was arthritogenic. This suggested that the arthritogenic property was intrinsic to the epitope and unrelated to its position within the CII molecule. To test this hypothesis, additional mutants were generated. The wild-type T-cell epitope of CB10 was deleted from its natural position, and the 'arthritogenic' GPAGPAGER T-cell epitope was inserted into the C-terminal portion of the CB10 peptide. The resulting peptide induced arthritis in B10.RIII mice. Adding a second copy of the T-cell determinant to other sites within CB10, however, had varying results. A second T-cell epitope located at the C-terminus of rCB10 significantly increased the incidence and severity of arthritis, while determinants placed in other positions had little effect. These data indicate that the T-cell epitope has intrinsic arthritogenic properties, but there are positional and structural constraints that affect its arthritogenicity. Enhanced arthritis was associated with an increased T-cell proliferation to the peptides, an increase in the level of inflammatory cytokines, and higher levels of anti-CII immunoglobulin. These data suggest that the position and copy number of T-cell determinants also affect the overall immune T-cell responses.
OBJECTIVES: By culturing primary early (8 to 12-weeks-old) human fetal hepatocytes with different conditions, to study the status of cell susceptibility to HBV. METHODS: During primary culture of 10-weeks-old human fetal hepatocytes with serum-free medium adding different differentiation-induced ingredients, to inoculate cell with HBV at certain time. Cell shape, function and markers of HBV infection are measured. RESULTS: 6 days after seeding, markers of mature hepatocytes are observed in cells cultured with 2.5mmol/L phenobarbital sodium, and these cells show susceptibility to HBV. Other ingredients cannot render hepatocytes susceptible to HBV. CONCLUSION: Phenobarbital sodium induces differentiation and susceptibility to HBV in primary culture of early human fetal hepatocytes.
OBJECTIVE: To observe the effects of Chinese herbal composition Zengjing Granule (ZJG) on the quality of sperm in the epididymis of infertile rats, and to study its therapeutic mechanisms of improving sperm quality. METHODS: A total of 40 GTW infertile rats were divided into 4 groups of 10 rats each, including an infertility group[GTW 2 mg/(ml.100 g)], a high-dosage group[ZJG 0.67 g/(ml.100 g) + GTW 2 mg/(ml.100 g)], a medium-dosage group[ZJG 0.33 g/(ml.100 g) + GTW 2 mg/(ml.100 g)], a low-dosage group[ZJG 0.17 g/(ml.100 g) + GTW 2 mg/(ml.100 g)], and a normal control group(1% CMC). This study consisted of a 3-week modeling period and a 3-week ZJG period. The changes of sperm quality, the thickness of the epididymal gland canal wall and sexual organ coefficient were detected after 3-week ZJG period. RESULTS: Of the 3 ZJG groups, the sperm density was (59.6 +/- 3.72), (63.3 +/- 5.70) and (69.7 +/- 6.91) x 10(6)/ml, the sperm motility rates were (65.4 +/- 6.33)%, (69.3 +/- 10.96)% and (72.6 +/- 9.61)%, the sperm deformity rates were (52.3 +/- 7.47)%, (46.2 +/- 7.73)% and (33.2 +/- 7.97)% respectively. The ZJG groups showed significant difference from the infertility group (P < 0.05), whose sperm density, motility and deformity were (13.1 +/- 6.81) x 10(6)/ml, (7.6 +/- 5.87)%, and (77.2 +/- 8.75)% respectively. But there was no significant difference between ZJG groups and the normal control group (P > 0.05), whose sperm density, motility and deformity were (75.6 +/- 10.82) x 10(6)/ml, (83.00 +/- 8.02)%, and (8.80 +/- 3.49)% respectively. The thickness of the epididymal gland canal wall was (37.07 +/- 3.38), (37.16 +/- 6.69) and (43.42 +/- 10.23) nm in the three ZJG groups respectively, different from the infertility group[(28.65 +/- 6.96) nm] (P < 0.05) significantly, but not from the normal control group [(45.79 +/- 11.13) nm] (P > 0.05). The ZJG groups showed an increase in the organ coefficient of the epididymal gland canal wall. And these was obvious statistical difference compared with the infertility group (P < 0.05), but no statistical significance compared with the normal control group (P > 0.05). CONCLUSIONS: ZJG can obviously improve the sperm quality of infertile rats. Its therapeutic mechanisms can be summed up as follows: restoring the thickness of epididymal gland wall, increasing the organ coefficient of testes and epididymis, and hence improving the spermatozoa maturing function of epididymis of infertile rats.
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Based on the significant enhancement of fluorescence intensity of carbaryl in inclusion complex, a spetrofluorimetric method with high sensitivity was developed for the determination of carbaryl in aqueous solution. Under the optimum conditions, the complex had excitation and emission maxima at 278 nm and 332 nm, respectively. The linear range of the method was 7.0 ng/ml-1500 ng/ml with a detection limit of 1.2 ng/ml. The proposed method was successfully used to determine quantitatively of carbaryl in cottonseeds.