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Biomedical subjects

Gang Wang

Publications and source records attributed to Gang Wang.

At least 91 records · Page 5Linked to original sources
PubMed2005

Oncolytic viral therapy for cervical and ovarian cancer cells by Sindbis virus AR339 strain.

PURPOSE: Recently, the application of replication-competent viruses has been studied as anticancer agents. Sindbis virus (SIN) is an RNA virus that belongs to the Alphavirus genus in the Togaviridae virus family. The AR339 strain of SIN has not been reported to induce any serious disease to humans. EXPERIMENTAL DESIGN: In this study, we evaluated the feasibility of the replication-competent SIN AR339 strain as an agent for cervical and ovarian cancer therapy. RESULTS: SIN infection was able to induce cytopathic effects and apoptosis in two cervical cancer cells (HeLaS3 and C33A) and three ovarian cancer cells (HOC-1, HAC-2, and OMC-3) but not in normal human keratinocytes in vitro. The analysis of cell viability, virus protein synthesis, and viral growth showed the cancer-specific cytotoxicity and virus growth of SIN. In nude mice, i.t. and i.v. inoculation of SIN resulted in significant regression of established cervical tumors implanted at their backs. Histologic studies revealed that systemic treatment with the single injection of SIN induces necrosis within tumors at a remote site. In the metastasis model of ovarian cancer, suppression of ascites formation was observed in nude mice with i.p. SIN treatment. By using an in vivo green fluorescent protein imaging system, we also showed that systemic treatment with SIN targeted tumors specifically. CONCLUSIONS: Our study suggested that SIN AR339 strain has a possibility as a novel agent for human cervical and ovarian cancer therapy.

Animals↗
PubMed2005

Event-related potential component associated with the recognition of three-dimensional objects.

To understand the physiological process underlying view-invariant object recognition, we designed a delayed matching-to-sample task under two different conditions: in the first condition, the sample and test stimuli were presented in the same view, and in the second, the two stimuli were presented in different views. The event-related potential (ERP) component, posterior N1, exhibited a significantly larger amplitude when the test image was in the same view as the sample image than when the test and the sample images were in different views. The result indicates that the posterior N1 is significantly sensitive to view association, and clarifies the difference between the neuronal activity that occurs in 3D object recognition and 2D image identification at the level of N1.

Adult↗
PubMed2005

Cys351 and Cys361 of the Na+/glucose cotransporter are important for both function and cell-surface expression.

Here, we identify Cys351 and Cys361 as novel residues critical for the function and plasma membrane targeting of the Na+/glucose transporter-1 (SGLT1). HEK-293 cells expressing the C351A and C361A mutants showed no detectable Na(+)-coupled uptake for alpha-methyl glucoside (AMG). Cell-surface biotinylation and Western blot revealed that the two mutants were overexpressed in 293 cells; however, none of them exhibited normal cell-surface expression. When reconstituted in proteoliposomes, mutant SGLT1s demonstrated significantly lower affinity for AMG compared with the wild-type transporter. Incubation with the reducing agent dithiothreitol did not alter the catalytic activity of wild-type protein, but surprisingly, it nearly restored the ability of SGLT1-C351A and -C361A to bind and translocate AMG. Thus, the C351A and C361A mutations might cause a global reorganization of the disulfide bonds of SGLT1. Furthermore, we showed that a double mutation (C351A/C361A) restored the cell-surface expression of the single C-to-A mutants (C351A and C361A).

Amino Acid Sequence↗
PubMed2005

The endogenous CXXC motif governs the cadmium sensitivity of the renal Na+/glucose co-transporter.

Cadmium (Cd2+) poisoning causes severe renal disorders manifested by defects in reabsorptive transport of various compounds. It is reported here that the renal brush-border membrane Na+/glucose co-transporter-1 (SGLT1) is a molecular target for Cd2+ toxicity. In micromolar concentrations, Cd2+ acted as a noncompetitive, partial inhibitor of methyl-D-glucopyranoside uptake in vesicles from COS-7 cells transiently expressing SGLT1. In contrast, only a modest effect in the closely related Na+/myo-inositol co-transporter-1 (SMIT1) was observed. The factor responsible for this difference was the CXXC motif (X can be any residue) at the cytoplasmic end of the eighth transmembrane segment (TM8) of SGLT1. Thus, a mutational transfer of this motif conveyed Cd2+ sensitivity to SMIT1. Moreover, mimicking the inhibitory effect of Cd2+, the biarsenical molecule FlAsH-EDT2 strongly inhibited the SGLT1 that had an engineered tetracysteine motif at the cytoplasmic end of TM8. The experiments also showed that covalent binding of the sulfhydryl reactive biotin-PEO-maleimide to the SGLT1 wild type but not to the mutant lacking the CXXC motif was suppressed by Cd2+. Taken together, these results suggest that in SGLT1, Cd2+ binding to the CXXC motif induces conformational changes that cause a partial inhibition of d-glucose transport.

Amino Acid Sequence↗
PubMed2005

[Diagnosis and management of primary hyperparathyrodism with urolithiasis].

OBJECTIVE: To investigate the diagnosis and management of primary hyperparathyroidism with urolithiasis. METHODS: The clinical data of 12 patients who were diagnosed with primary hyperparathyroidism with urolithiasis from January 1998 to June 2004 were analyzed retrospectively. RESULTS: Four male and five female patients were demonstrated pathologically as parathyroid adenoma, with a mean age of 45.7 +/- 11.8 years (26 approximately 57) and a stone history of 8.3 +/- 6.4 years (0.5 approximately 22). Their serum calcium and PTH level were elevated obviously, while serum phosphate of 66% patients were lowered. The positive rate and accuracy of ultrasound, CT and (99m)TC-MIBI imaging were 67%, 100%, and 100% and 67%, 75%, 100% respectively. After resection of the parathyroid adenoma, the patients' serum calcium and PTH returned to normal. The other data of 3 cases without parathyroid adenoma. all males aged 45 approximately 54, were also investigated. CONCLUSIONS: Serum calcium level above 2.96 mmol/L and PTH 3.9 or more times as normal in patients with recurrent or bilateral urolithiasis should be suspected with primary hyperparathyroidism. (99m)TC-MIBI image functions best in preoperative localization of the abnormal gland. Parathyroidectomy is the curative approach for the disease. Stones should be followed up after operation and appropriate treatment should be employed when needed.

Adenoma↗
PubMed2005

Mediator requirement for both recruitment and postrecruitment steps in transcription initiation.

Mediator complexes are required for activators to stimulate Pol II preinitiation complex assembly on an associated promoter. We show here that for the mouse Egr1 gene, controlled largely by MAP kinase phosphorylation of the ELK1 transcription factor, the MED23 Mediator subunit that interacts with phospho-ELK1 is also required to stimulate Pol II initiation at a step subsequent to preinitiation complex assembly. In Med23-/- cells, histone acetylation, methylation, and chromatin remodeling complex association at the Egr1 promoter were equivalent to that of wild-type cells, yet Egr1 induction was greatly reduced. MAP kinase activation stimulated Pol II and GTF promoter binding. However, the difference in factor binding between wild-type and mutant cells was much less than the difference in transcription, and Pol II remained localized to the promoter in mutant cells. These results indicate that an interaction with MED23 stimulates initiation by promoter bound Pol II in addition to Pol II and GTF recruitment.

Acetylation↗
PubMed2005

Cytoplasmic and nuclear retained DMPK mRNAs are targets for RNA interference in myotonic dystrophy cells.

Small interfering RNA (siRNA) duplexes induce the specific cleavage of target RNAs in mammalian cells. Their involvement in down-regulation of gene expression is termed RNA interference (RNAi). It is widely believed that RNAi predominates in the cytoplasm. We report here the co-existence of cytoplasmic and nuclear RNAi phenomena in primary human myotonic dystrophy type 1 (DM1) cells by targeting myotonic dystrophy protein kinase (DMPK) mRNAs. Heterozygote DM1 myoblasts from a human DM1 fetus produce a nuclear retained mutant DMPK transcript with large CUG repeats ( approximately 3,200) from one allele of the DMPK gene and a wild type transcript with 18 CUG repeats, thus providing for both a nuclear and cytoplasmic expression profile to be evaluated. We demonstrate here for the first time down-regulation of the endogenous nuclear retained mutant DMPK mRNAs targeted with lentivirus-delivered short hairpin RNAs (shRNAs). This nuclear RNAi(-like) phenomenon was not observed when synthetic siRNAs were delivered by cationic lipids, suggesting either a link between processing of the shRNA and nuclear import or a separate pathway for processing shRNAs in the nuclei. Our observation of simultaneous RNAi on both cytoplasmic and nuclear retained DMPK has important implications for post-transcriptional gene regulation in both compartments of mammalian cells.

Active Transport, Cell Nucleus↗
PubMed2005

Stable isotope labeling-mass spectrometry analysis of methyl- and pyridyloxobutyl-guanine adducts of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in p53-derived DNA sequences.

The p53 tumor suppressor gene is a primary target in smoking-induced lung cancer. Interestingly, p53 mutations observed in lung tumors of smokers are concentrated at guanine bases within endogenously methylated (Me)CG dinucleotides, e.g., codons 157, 158, 245, 248, and 273 ((Me)C = 5-methylcytosine). One possible mechanism for the increased mutagenesis at these sites involves targeted binding of metabolically activated tobacco carcinogens to (Me)CG sequences. In the present work, a stable isotope labeling HPLC-ESI(+)-MS/MS approach was employed to analyze the formation of guanine lesions induced by the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) within DNA duplexes representing p53 mutational "hot spots" and surrounding sequences. Synthetic DNA duplexes containing p53 codons 153-159, 243-250, and 269-275 were prepared, where (Me)C was incorporated at all physiologically methylated CG sites. In each duplex, one of the guanine bases was replaced with [1,7,NH(2)-(15)N(3)-2-(13)C]-guanine, which served as an isotope "tag" to enable specific quantification of guanine lesions originating from that position. After incubation with NNK diazohydroxides, HPLC-ESI(+)-MS/MS analysis was used to determine the yields of NNK adducts at the isotopically labeled guanine and at unlabeled guanine bases elsewhere in the sequence. We found that N7-methyl-2'-deoxyguanosine and N7-[4-oxo-4-(3-pyridyl)but-1-yl]guanine lesions were overproduced at the 3'-guanine bases within polypurine runs, while the formation of O(6)-methyl-2'-deoxyguanosine and O(6)-[4-oxo-4-(3-pyridyl)but-1-yl]-2'-deoxyguanosine adducts was specifically preferred at the 3'-guanine base of 5'-GG and 5'-GGG sequences. In contrast, the presence of 5'-neighboring (Me)C inhibited O(6)-guanine adduct formation. These results indicate that the N7- and O(6)-guanine adducts of NNK are not overproduced at the endogenously methylated CG dinucleotides within the p53 tumor suppressor gene, suggesting that factors other than NNK adduct formation are responsible for mutagenesis at these sites.

Base Sequence↗
PubMed2005

Study on the behavior of hyper-rayleigh scattering for silver nanoparticles with aggregation effects.

The absorption spectra as well as the Hyper-Rayleigh scattering (HRS) signals of a highly monodisperse 10.5-nm diameter silver colloids with the addition of KNO(3) and pyridine have been measured. Strongly enhanced HRS signals are observed by 15x and 6x, respectively. Through size distribution and TEM measurements, the morphology of aggregated silver nanoparticles has been observed as a chainlike aggregation. The dramatically enhanced second-order nonlinearity was explained by the enhanced electromagnetic (EM) field near the surface of the silver nanoparticles as they approached. The different enhancement between these two kinds of aggregates was considered with the diversity of separated distance between silver nanoparticles. The experimental results reveal that there is an optimum size for the aggregates to yield the maximum HRS response.

Journal Article↗
PubMed2005

Construction of a cucumber genetic linkage map with SRAP markers and location of the genes for lateral branch traits.

Using SRAP (sequence-related amplified polymorphism) markers a genetic linkage map of cucumber was constructed with a population consisting of 138 F2 individuals derived from a cross of the two cucumber lines, S06 and S52. In the survey of parental polymorphisms with 182 primer combinations, 64 polymorphism-revealing primer pairs were screened out, which generated totally 108 polymorphic bands with an average of 1.7 bands per primer pair and at most 6 bands from one primer pair. The constructed molecular linkage map included 92 loci, distributed in seven linkage groups and spanning 1164.2 cM in length with an average genetic distance of 12.6 cM between two neighboring loci. Based on this linkage map, the quantitative trait loci (QTL) for the lateral branch number (Ibn) and the lateral branch average length (Ibl) in cucumber were identified by QTLMapperl.6. A major QTL Ibn1 located between ME11 SA4B and ME5EM5 in LG2 could explain 10.63% of the total variation with its positively effecting allele from S06. A major QTL Ibl1 located between DC1OD3 and DC1EM14 in LG2 could account for 10.38% of the total variation with its positively effecting allele from S06.

Chromosome Mapping↗
PubMed2005

Protective effect of nitric oxide against oxidative stress under ultraviolet-B radiation.

The response of bean leaves to UV-B radiation was extensively investigated. UV-B radiation caused increase of ion leakage, loss of chlorophyll, and decrease of the maximum efficiency of PSII photochemistry (Fv/Fm) and the quantum yield of PSII electron transport (PhiPSII) of bean leaves. H2O2 contents and the extent of thylakoid membrane protein oxidation increased, indicated by the decrease of thiol contents and the increase of carbonyl contents with the duration of UV-B radiation. Addition of sodium nitroprusside, a nitric oxide (NO) donor, can partially alleviate UV-B induced decrease of chlorophyll contents, Fv/Fm and PhiPSII. Moreover, the oxidative damage to the thylakoid membrane was alleviated by NO. The potassium salt of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger, arrested NO mediated protective effects against UV-B induced oxidative damage. Incubation of thylakoid membrane with increasing H2O2 concentrations showed a progressive enhancement in carbonyl contents. H2O2 contents were decreased in the presence of NO under UV-B radiation through increased activities of superoxide dismutases, ascorbate peroxidases, and catalases. Taken together, the results suggest that NO can effectively protect plants from UV-B damage mostly probably mediated by enhanced activities of antioxidant enzymes.

Antioxidants↗
PubMed2005

The stability of predator-prey systems subject to the Allee effects.

In recent years, many theoreticians and experimentalists have concentrated on the processes that affect the stability of predator-prey systems. But few papers have addressed the Allee effect with focus on the their stability. In this paper, we select two classical models describing predator-prey systems and introduce the Allee effects into the dynamics of both the predator and prey populations in these models, respectively. By combining mathematical analysis with numerical simulation, we have shown that the Allee effect may be a destabilizing force in predator-prey systems: the equilibrium point of the system could be changed from stable to unstable or otherwise, the system, even when it is stable, will take much longer time to reach the stable state. We also conclude that the equilibrium of the prey population will be enlarged due to the Allee effect of the predator, but the Allee effects of the prey may decrease the equilibrium value of the predator, or that of both the predator and prey. It should also be pointed out that the impact of the Allee effects of predator and prey due to different mechanisms on different predator-prey systems could also vary.

Animals↗
PubMed2005

Relationship between bone mineral density and syndrome types described in traditional chinese medicine in chronic obstructive pulmonary disease: a preliminary clinical observation.

Osteoporosis is a common finding following chronic obstructive pulmonary disease (COPD), but there are few reports on the relationship between bone mineral density (BMD) and the syndrome types described in traditional Chinese medicine (TCM) in patients with COPD. A cross-sectional medical survey was used in this study. Twenty-six male patients with COPD and 26 age-matched male healthy subjects were recruited. The symptom questionnaire survey of TCM was implemented, and thereafter the COPD patients were divided into two subgroups: type of deficiency of the lung and spleen (TDLS) and type of deficiency of the lung, spleen and kidney (TDLSK). BMD of lumbar spine (L2-4), non-dominant femoral neck (Neck), Ward's triangle (Ward's), and great trochanter (Troch) were measured by dual-energy x-ray absorptiometry. In addition, the other bone turnover markers were also examined. The results showed that BMD was much more decreased in TDLSK than that in TDLS patients (p < 0.05), and BMD in the patients of the TDLS subgroup without symptoms of kidney-vacuity has showed the decreased trend from healthy subjects to TDLS patients. Furthermore, there was a higher incidence of osteoporosis in patients with TDLSK compared with that in TDLS (p < 0.05, OR > 2.0). Therefore, the data suggest that: (1) BMD might be a marker more sensitive than the symptom for the diagnosis of kidney-vacuity in COPD patients; (2) the deficiency of kidney would be the key factor of bone mineral loss; and (3) that invigorating the kidney should be performed in the phase of TDLS in COPD patients in advance.

Absorptiometry, Photon↗
PubMed2005

Cloning and expression of a novel lipase gene from Pseudomonas fluorescens B52.

A novel lipase gene (lipB52) was isolated directly from the genomic DNA of Pseudomonas fluorescens B52 with the genome-walking method, an effective method for isolating lipase gene from bacteria. There was an open reading frame (ORF) of 1854 bp, which encoded 617 amino acids. The lipase gene (lipB52) was cloned into expression vector pPIC9K and successfully integrated into a heterologous fungal host, Pichia pastoris KM71, and the recombinant Pichia pastoris were screened with a high throughput method. The recombinant was induced by methanol to secrete active lipase into the culture medium. The recombinant lipase LipB52 was also purified and characterized. The optimum temperature for the purified lipase LipB52 was 40 degrees C at pH 8.0. It exhibited better thermostability and pH stability than its homologs.

Cloning, Molecular↗
PubMed2005

[Protective effects of ulinastatin on ischemia/reperfusion injury in the rabbit lung in traumatic hemorrhagic shock].

OBJECTIVE: To investigate the effects and mechanisms of ulinastatin on activities of myeloperoxidase (MPO) in lung tissue and neutrophil elastase (NE) in bronchoalveolar lavage fluid and to evaluate the protective effects of ulinastatin on rabbit lung in traumatic hemorrhagic shock. METHODS: Thirty rabbits were randomly assigned to three groups: control group, traumatic hemorrhagic shock group and ulinastatin-treatment group. The traumatic hemorrhagic shock model was reproduced by producing: femur fracture and femoral artery bleeding to reduce the mean artery pressure to (40+/-5) mmHg (1 mmHg=0.133 kPa). The hypotension was maintained 90 minutes before the shed blood and equivalent amount of Ringer's lactate was infused. Four hours after blood volume compensation, the activities of MPO in lung tissue and NE in bronchoalveolar lavage fluid (BALF) were measured, and the extravascular lung water volume was determined. RESULTS: Compared with control group, the activities of either MPO in lung tissue or NE in BALF appeared to be increased in the ulinastatin-treatment group (both P<0.05), but their levels were significantly higher in traumatic hemorrhagic shock group(both P<0.05). The extravascular lung water volume was increased significantly in the two experimental group (both P<0.05), however it was more pronounced in traumatic hemorrhagic shock group (all P<0.05). CONCLUSION: Ulinastatin can inhibit the increase in the activities of MPO in lung tissue and NE in BALF, and possesses potential protective effects on the lung tissue in traumatic hemorrhagic shock.

Animals↗
PubMed2005

[The combination of VEGF-C expressing vector and the detection of expression in Tca8113 cell].

OBJECTIVE: To investigate the functional expression of a truncated VEGF-C gene in mammalian cells. METHODS: A truncated VEGF-C cDNA (with 5'-terminal cleaved between residues 207/208) was used to construct a pcDNA3.1(+)-VEGF-C recombined plasmid, which was cloned into a lingual SCC cell line (Tca8113) by lipid-mediated transfection. The expression of VEGF-C was detected by Western blotting and immunohistochemical staining. RESULTS: The VEGF-C fragment was successfully ligated into the pcDNA3.1(+) between EcoR I and Xho I multiclone sites. By Western blotting, the relative molecular mass 53 x 10(3) and 29 x 10(3) forms of VEGF-C were detected in cell lysates of VEGF-C transfected cells (VcTca), while the relative molecular mass 29 x 10(3) form of VEGF-C presented the only band in culture media. According to immunohistochemistry, the VcTca cells showed intensive cytoplasm positive reaction to VEGF-C, whereas faint reaction was found in non-transfected cells and pcDNA3.1(+) mock transfected cells. CONCLUSION: The results indicated that the truncated VEGF-C cDNA was sufficient for expression, secretion and activation when it was transfected into Tca8113 cell.

Carcinoma, Squamous Cell↗