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Biomedical subjects

Ying Huang

Publications and source records attributed to Ying Huang.

At least 181 records · Page 10Linked to original sources
PubMed2003

Retinoic acid-induced AP-1 transcriptional activity regulates B16 mouse melanoma growth inhibition and differentiation.

Retinoic acid (RA) inhibits growth and induces differentiation of B16 mouse melanoma cells. These effects are accompanied by a large increase in PKCalpha mRNA and protein levels and surprisingly an increase in activating protein-1 (AP-1) transcriptional activity. To further investigate the RA-induced AP-1 activity we established clones of B16 cells stably expressing an AP-1-luciferase reporter gene. Treatment of these clones with phorbol dibutyrate increased AP-1 activity which peaked at 2-4 h and returned to baseline level by 24 h. In contrast, RA treatment resulted in a slow increase in AP-1 activity that reached a maximum level at 48 h and was maintained for the duration of the treatment. We tested the importance of the RA-induced AP-1 activity by establishing clones which stably express a dominant negative fos gene (A-fos) and have greatly diminished AP-1 activity. Growth rates of untreated A-fos expressing cells were similar to wt B16 and clones not expressing A-fos. However, clones expressing the dominant-negative fos had a markedly decreased sensitivity to RA-induced inhibition of anchorage-dependent and -independent growth. Treatment of wt B16 cells for 48 h with RA increased melanin production by two to fourfold, but this effect was completely lost in the A-fos clones. The ability of RA to induce RARbeta and PKCalpha expression was retained in A-fos clones, suggesting that A-fos was not interfering with RAR transcription activation functions. We tested whether the RA-induced AP-1 activity might be mediated by the ERK1/2 MAPK pathway. Inhibition of ERK1/2 phosphorylation stimulated AP-1 activity, which was not additive to that induced by RA. This finding raises the possibility that this MAPK pathway may be a target of retinoid action. Our observations suggest that AP-1 transcriptional activity induced by RA likely plays an important role in the biological changes mediated by this retinoid in B16 melanoma cells.

Animals↗
PubMed2003

Chlorobenzenes removal from municipal solid waste incineration fly ash by surfactant-assisted column flotation.

The organic contaminants in municipal solid waste incineration (MSWI) fly ash, including chlorinated aromatic compounds and polycyclic aromatic hydrocarbons, have high toxicity and a potential negative impact on the environment. An effective and low energy consumption technique to remove the organic contaminants from MSWI fly ash is required urgently. Organic contaminants, such as chlorobenzenes (CBzs), in MSWI fly ash are known to become enriched in the unburnt carbon (UC) fraction. It is proposed that removal of UC from fly ash will result in the effective removal of most organic micropollutants. In this research, we use a technique of surfactant-assisted column flotation to decontaminate MSWI fly ash by removal of the CBzs-enriched UC from MSWI fly ash. We find that 39.8% of CBzs can be removed from fresh MSWI fly ash with 61.7% UC removal efficiency, whereas only 33.2% of CBzs can be removed from weathered MSWI fly ash with a low UC removal efficiency of 33.7%. By adding a mixture of two kinds of surfactants: sorbitan mono-oleate and polyoxyethylene (20) sorbitan mono-oleate to the weathered fly ash, 47.0% of CBzs were removed at the hydrophile lipophile balance value of 13.5, while the UC removal efficiency increased to 49.0%. The results show that surfactants can enhance CBzs and UC removal efficiencies during the column flotation process. Higher CBzs and UC removal efficiencies can be expected by further optimizing the conditions of surfactant-assisted column flotation.

Air Pollutants↗
PubMed2003

Removal of unburned carbon from municipal solid waste fly ash by column flotation.

Unburned carbon (UC) is the major source of organic contaminants in municipal solid waste (MSW) fly ash. So most organic contaminants can be removed by the removal of the UC from the MSW fly ash. In this paper, we first used a technique of column flotation to remove UC from MSW fly ash. The influences of column flotation parameters on the recovery efficiency of UC were systematically studied. It was found that the UC recovery efficiency was greatly influenced by the gas flow rate, pH value, collector kerosene's concentration and the types of fly ash. By optimizing the above parameters, we have successfully removed 61.2% of the UC from MSW fly ash having 5.24% UC content. The removal mechanism was well accounted for the kinetic theory of column flotation and surface-chemistry theory. The results indicate that the column flotation technique is effective in removing the UC from MSW fly ash, and show that there is a strong possibility for practical application of this technique in removing the organic contaminants from MSW fly ash.

Air↗
PubMed2003

Glutamine decreases lipopolysaccharide-induced IL-8 production in Caco-2 cells through a non-NF-kappaB p50 mechanism.

Glutamine (Gln) supplementation has been shown to decrease production of pro-inflammatory cytokines by the human intestinal mucosa. The mechanism of this is poorly understood. We hypothesize that Gln down-regulates lipopolysaccharide (LPS)-stimulated pro-inflammatory cytokine production in Caco-2 cells by nuclear factor-kappa B (NF-kappaB). Caco-2 cells were incubated with different concentrations of Gln with or without methionine sulfoximine (MS, an inhibitor of glutamine synthetase) before stimulation with LPS. IL-6, IL-8, IL-10 and TNF-alpha protein and mRNA level were determined. NF-kappaB translocation was determined using an ELISA-based kit. IL-8 was the only detectable cytokine/chemokine. The largest amount of IL-8 was secreted by cells in the presence of MS with no Gln in the medium after exposure to LPS. LPS increased IL-8 production, peaking 10h after LPS administration. The addition of Gln (0.5 or 5.0mM) decreased IL-8 peptide and mRNA expression. LPS increased NF-kappaB nuclear translocation in the presence or absence of MS. Neither Gln nor MS altered NF-kappaB nuclear translocation. These results indicate that the lack of glutamine increases IL-8 production by Caco-2 cells after LPS stimulation. However, the glutamine-mediated decrease in LPS-stimulated IL-8 production is not associated with NF-kappaB p50 nuclear binding.

Caco-2 Cells↗
PubMed2003

Synergistic antiviral activity of human interferon combinations in the hepatitis C virus replicon system.

The use of type I interferon (IFN), in combination with ribvirin, to treat chronic hepatitis C virus (HCV) infection has many drawbacks that prevent widespread application, ultimately leading to a significant unmet clinical need. Potential improvements in IFN therapy through targeted delivery, molecular alteration, and combination with other agents are ongoing in an attempt to decrease adverse effects and increase efficacy. In this report, the HCV replicon cell culture system was used to assess potential synergistic antiviral effects of multiple IFN species when administered in combination. Quantitative analysis of HCV replicon RNA by TaqMan (PE Applied Biosystems, Foster City, CA) and qualitative analysis of HCV protein expression were used to measure the antiviral efficacy of individual and combination IFN treatments, and synergistic responses of IFN combinations were determined through statistical analysis of the TaqMan results. We found that when administered simultaneously, type I/II IFN combinations (IFN-alpha2b + IFN-gamma or IFN-beta + IFN-gamma) resulted in dramatic antiviral synergy, whereas a type I/I combination (IFN-alpha2b + IFN-beta) demonstrated a slightly antagonistic profile. The synergistic effect is likely due to differential cell surface receptors and signaling pathways employed by types I and II IFNs. Conversely, all type I IFN species bind the same receptor and signal through similar pathways, possibly accounting for the nearly additive response observed. In support of this hypothesis, IFN treatment resulted in differential induction of Stat1 phosphorylation at Tyr 701. In conclusion, simultaneous type I/II IFN combination treatment may allow an overall decreased effective IFN dose, which may reduce the side effect profiles that hinder current therapy.

Antiviral Agents↗
PubMed2003

[An insertion mutant of LeuRS with 116 amino acid residues has full activity].

Escherichia coli leucyl-tRNA synthetase (LeuRS) belongs to class I aminoacyl-tRNA synthetases. It consists of 860 amino acid residues and catalyzes the leucylation of tRNA(Leu). An insertion of its 253-368 peptide fragment between 368 to 369 in CP1 domain of this enzyme was shown to maintain the activity of the enzyme, and the insertion mutant was named as LeuRS-C. Because the insertion mutant of LeuRS was sensitive to operation of the purification, a plasmid containing the gene encoding LeuRS with His(6)-tag at its N-terminus was constructed to facilitate the purification of His(6)-LeuRS-C through one-step affinity chromatography on Ni(2+)-NTA column. The purified His(6)-LeuRS-C had full activity as the native LeuRS with His-tag at the N-terminus (His(6)-LeuRS), although the mutant enzyme had an insertion of 116 amino acid residues. The kinetic parameters of His(6)-LeuRS-C were determined. The secondary structure estimated by CD spectrum and thermal stability of the insertion mutant was compared with those of His(6)-LeuRS, respectively.

Circular Dichroism↗
PubMed2003

[Chronic hepatitis B treated with domestic manufactured lamivudine in 2200 patients: a phase IV study].

OBJECTIVE: To further verify the efficacy and safety of locally manufactured lamivudine on patients with chronic hepatitis B (CHB). METHODS: 2200 patients with CHB were recruited and received lamivudine orally 100 mg once daily for 12 months. The efficacy assessments included virologic response rate (defined by the absence of serum HBV DNA, HBeAg loss and HBeAg/HBeAb seroconversion), percentage of patients with normalization of alanine aminotransferase (ALT). Meanwhile improvement of quality of life (QOL) measured by mos SF-36 QOL questionnaire and liver histology evaluation were conducted in some patients. The safety assessments included adverse events, serious adverse events and laboratory abnormalities. All 2200 patients received at least one dose of medication and were all included in the safety population. RESULTS: Ninety seven percent of patients (2137/2200) recruited were HBV DNA positive by dot blot (sensitivity GRT or equal to 1.0 pg/ml) at baseline. At the end of 12 months treatment, HBV DNA was undetectable in 80% patients (1538/1920) with HBV DNA positive before treatment. Among the 79%(1744/2200) of the patients recruited had positive HBV DNA accompanied abnormal ALT levels at baseline, 72% patients became ALT normal. And among the 84% (1843/2200) of the patients recruited were HBV DNA and HBeAg positive, anti-HBe negative, 16% (269/1650) patients achieved HBeAg/HBeAb seroconversion after 12 months of lamivudine treatment. The HBeAg/HBeAb seroconversion rate was positive correlation to the ALT level before treatment. A total of 304 patients completed the health-related QOL questionnaire. After 12 months treatment, lamivudine improved both their physical and mental health, especially for their mental health. 133 evaluable, paired liver biopsies were obtained for histological assessment, among whom 115 patients had abnormal ALT levels at baseline. Compared with pre-treatment most of their liver injury got alleviated (51.9%) or no further deterioration (36%), only 12% worsening. During the 12 months treatment, 9% patients withdrew from the study and 17% patients showed at least one adverse event, mild or moderate. There were no obvious difference between this study and the previously reported lamivudine Phase II or III study with regard to the kinds, incidence and severity of adverse events. CONCLUSION: The efficacy and safety profile of the locally manufactured lamivudine 100 mg tablets are similar with those of the previously reported available lamivudine tablets imported in treating Chinese chronic hepatitis B patients.

Adolescent↗
PubMed2003

[Determination of salbutamol in human plasma by column-switching HPLC with UV detection].

OBJECTIVE: To make better the RP-HPLC method with column-switching technique for the determination of salbutamol in human plasma. METHODS: A high-pressure flow channel selection valve and Kromasil C18 pretreatment column (20 x 4 mm, 5 microns), Ultrasphere Cyano analysis column (250 mm x 4.6 mm, 5 um, Beckman) were used. To the plasma sample 1.0 ml, 0.5 ml phosphate buffer (2.0 mol/L, pH 9.0) containing 0.4% diphenylboric acid 2-aminoethyl ester was added, then extraction was performed with the use of 4.0 ml chloroform containing 1% tetraoctylammonium bromide. The organic layer was removed and extracted again with 300 microliters (0.08 mol/L) acetic acid. 100 microliters of the acid layer was injected onto the column. The mobile phase of pH 2.8, 0.025 mol/L phosphate buffer-acetonitrile-methanol (95:4:1) was pumped at the rate of 0.9 and 1.0 ml.min-1 through the pretreatment and analysis column, respectively. The column-switching time was from 0.7 min to 1.5 min. The detector at 0.002 aufs was set at 224 nm. RESULTS: The retention time for salbutamol was 6.7 min and that for internal standard (morphine) 7.6 min. The standard curve was linear over the concentration range from 0.5 to 32 micrograms/L. The lowest concentration of detection in plasma was 0.5 microgram/L. The method recovery was 96%-107%; the intra-day RSD less than 5%; the inter-day RSD less than 8%. CONCLUSION: This method was found to be simple, rapid, sensitive and accurate for determination of salbutamol in human plasma.

Adrenergic beta-Agonists↗
PubMed2003

[Intensity modulated radiation therapy for 49 patients with recurrent nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the feasibility, toxicity and tumor control of intensity modulated radiation therapy (IMRT) for recurrent nasopharyngeal carcinoma. METHODS: Fourty-nine patients (Karnofsky performance status (KPS) >or= 80) with local-regional recurrence in the nasopharynx were treated with full course IMRT. Three patients with cervical lymph node metastasis (N1 2 and N3 1) were further supplemented with 5 to 6 courses of chemotherapy (Cisplatin + 5-Fu) after IMRT. RESULTS: The results of treatment plan showed that the mean dose of covering gross tumor volume (GTV) (D(95)) in the nasopharynx was 68.09 Gy and the mean volume of GTV (V(95)) receiving the 95% dose was 98.46%. The mean dose of GTV, clinical target volume CTV1 and CTV2 in the targets were 71.40 Gy, 63.63 Gy and 59.81 Gy. The median follow-up time was 9 months (range 3 to 16 months). The local-regional progression-free survival was 100% with local-regional residual disease in 3 (6.1%) cases but was complicated with nasopharyngeal mucosa necrosis in 14 (28.6%) cases after IMRT. CONCLUSION: Intensity modulated radiation therapy, as a re-treatment option for recurrent nasopharyngeal carcinoma, is able to improve the tumor target coverage and spare the adjacent critical structures. As high dose IMRT can result in radio-necrosis of nasopharyngeal mucosa, the prescription dose of GTV should be suitably decreased to 60 - 65 Gy.

Adult↗
PubMed2003

[Chromosomal abnormalities in two cases of goats with sexual deformity].

We herein report two cases of goats with sexual deformity. They had two systems of reproductive organs and the karyotype analysis showed mosaicism for their sex chromosomes, i.e., 60, XX / XY. The proportion of XX cell line was 42% and 54%, while XY cell line was 58% and 46%, respectively, in the two abnormal goats.

English Abstract↗
PubMed2003

[Goat beta-lactoglobulin gene cloning and high expression in the mammary gland of transgenic mice].

To clone goat beta-lactoglobulin (BLG) gene,two fragments were amplified from goat genomic DNA by LD-PCR method. The fragments were inserted in T-vectors before being spliced into the whole 7.2 kb BLG gene at a single restriction enzyme site of NarI. Consequently, the eukaryotic expression vector was constructed. All the clones were proved to be correct by restriction enzyme cutting and sequencing analysis. Six Founders (3 male symbol, 3 female symbol) of goat BLG transgenic mice were obtained by microinjection and BLG genes integration were confirmed by both PCR and Southern blot analyses. The milk was collected from two lactating female transgenic mice and goat BLG protein contents were measured with ELISA. The results showed that goat BLG protein in milk of the two mice were 23.49 mg/mL and 2.19 mg/mL, respectively.

English Abstract↗
PubMed2002

Apo2L/TRAIL differentially modulates the apoptotic effects of sulindac and a COX-2 selective non-steroidal anti-inflammatory agent in Bax-deficient cells.

The nonsteroidal anti-inflammatory drugs (NSAIDs) are believed to mediate their anticancer effects by inducing apoptosis but the molecular mechanisms of their apoptotic effects remain largely unknown. Here we report that two different NSAIDs, sulindac sulfide and SC-'236 engage the death receptor 5 (DR5) and mitochondrial pathways to mediate apoptosis in human colon cancer cells. We show that sulindac sulfide and SC-'236-induced apoptosis is coupled with upregulation of DR5, caspase 8 activation and Bid cleavage. Thus, a cross talk appears to exist between the DR5 and mitochondrial pathways during apoptosis induced by these NSAIDs. We further show that sulindac sulfide and SC-'236-induced DR5 upregulation occurs independent of the COX inhibitory effects of these NSAIDs. Using Bax-proficient (Bax+/-) and Bax-deficient (Bax-/-) HCT116 human colon cancer cells, we further demonstrate that Apo2L/TRAIL differentially modulates the apoptotic effects of sulindac sulfide and SC-'236. For example, sulindac sulfide upregulates DR5 in both Bax-deficient and proficient cells, but Apo2L/TRAIL efficiently potentiates sulindac sulfide-induced apoptosis as well as activation of caspase-8, -9 and -3 only in Bax-proficient cells. SC-'236 also upregulates DR5 in both Bax-proficient and Bax-deficient cells but Apo2L/TRAIL potentiates SC-'236-mediated apoptosis and caspases-8 and -3 activation in both Bax-proficient and Bax-deficient cells. Further, in Bax-deficient cells, neither sulindac sulfide nor SC-'236 in combination with Apo2L/TRAIL effectively promotes the release of cytochrome c from mitochondria into cytosol and caspase-9 activation. Collectively, our results suggest that unlike sulindac sulfide, SC-'236 in combination with Apo2L/TRAIL can overcome Bax deficiency to induce apoptosis. These results have important clinical implications in that the tumors harboring Bax mutations are likely to develop resistance to sulindac but not to SC-'236-like NSAIDs. In conclusion, the data presented herein form the basis of future in-depth studies to further explore the utility of Apo2L/TRAIL and NSAIDs, in combination, as a novel cancer preventive/therapeutic strategy.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Catalytic oxidations of steroid substrates by artificial cytochrome p-450 enzymes.

Catalysts comprising manganese-porphyrins carrying cyclodextrin binding groups are able to perform hydroxylations with substrate selectivity and regio- and stereoselectivity and high catalytic turnovers. The geometries of the catalyst/substrate complexes override intrinsic substrate reactivities, permitting attack on geometrically accessible saturated carbons of steroids in the presence of secondary carbinol groups and carbon-carbon double bonds, as in enzymatic reactions. Selective hydroxylations of steroid carbon 9 positions are of particular practical interest.

Binding Sites↗
PubMed2002

Dielectrophoretic cell separation and gene expression profiling on microelectronic chip arrays.

Cell membrane dielectric properties of five different cultivated cell lines and human peripheral blood mononuclear cells (PBMC) were determined from dielectrophoretic crossover frequency measurements on a 5 x 5 microelectronic chip array. Based on distinct dielectric property differences between individual cell types, efficient cell separations were achieved by dielectrophoresis on this 5 x 5 array, which included separation of monocytic cells (U937) or human T cell leukemia virus type 1 (HTLV-1) tax-transformed cells (Ind-2) from PBMC, as well as separation of neuroblastoma cells (SH-SY5Y) from glioma cells (HTB). The purity of dielectrophoretically separated cells can be greater than 95%. Expression profiles of IL-1, TNF-alpha, and TGF-beta genes for U937 cells mixed with PBMC before and after the separation were determined by a means of electric field-facilitated hybridization on a 10 x 10 microelectronic chip array. By using the expression levels of pure U937 cells as a control, it was shown that the gene expression profiles of the postseparation cells were significantly different from those of the preseparation cell mixtures. The increase in gene expression levels for U937 cells upon lipopolysaccharide induction could be accurately determined only in the postseparation cells, while the preseparation samples masked these changes. Furthermore, by cultivating the separated HTB and SH-SY5Y cells and measuring expression of the stress-related gene c-fos, dielectrophoretic forces were shown to have little effect on cell survival and stress. The presented approach of using microelectronic chip arrays for both cell separation and gene expression profiling provides a great potential for accurate genetic analysis of specific cell subpopulations in heterogeneous samples.

Cell Line↗
PubMed2002

Endoplasmic reticulum calcium pool depletion-induced apoptosis is coupled with activation of the death receptor 5 pathway.

Thapsigargin (TG), by inducing perturbations in cellular Ca(2+) homeostasis, has been shown to induce apoptosis. The molecular mechanisms of Ca(2+) perturbation-induced apoptosis are not fully understood. In this study, we demonstrate for the first time that TG-mediated perturbations in Ca(2+) homeostasis are coupled with activation of the death receptor 5 (DR5)-dependent apoptotic pathway in human cancer cells. TG selectively upregulated DR5 but had no effect on the expression of the other TRAIL receptor, DR4. TG also upregulated the expression of the DR5 ligand TRAIL (tumor necrosis factor-related apoptosis inducing ligand), albeit in a cell-type specific manner. TG-induced apoptosis has been shown to be associated with activation of the mitochondrial pathway. We found that TG upregulation of DR5 and TRAIL was coupled with caspase 8 activation and Bid cleavage, suggesting that the TG-regulated DR5 pathway could be linked to the mitochondrial pathway. TG enhanced not only DR5 mRNA stability but also increased induction of the DR5 genomic promoter-reporter gene. The TG-induced increase in DR5 expression appeared to occur as a consequence of TG-induced endoplasmic reticulum (ER) Ca(2+) pool depletion. Thus, we report our novel findings that ER Ca(2+) pool depletion-induced apoptotic signals are mediated, at least in part, via a DR5-dependent apoptotic pathway and there appears to be a cross-talk between the death receptor and mitochondrial pathways.

Apoptosis↗
PubMed2002

Transcriptional silencing in Saccharomyces cerevisiae and Schizosaccharomyces pombe.

Transcriptional silencing is a heritable form of gene inactivation that involves the assembly of large regions of DNA into a specialized chromatin structure that inhibits transcription. This phenomenon is responsible for inhibiting transcription at silent mating-type loci, telomeres and rDNA repeats in both budding yeast Saccharomyces cerevisiae and fission yeast Schizosaccharomyces pombe, as well as at centromeres in fission yeast. Although transcriptional silencing in both S.cerevisiae and S.pombe involves modification of chromatin, no apparent amino acid sequence similarities have been reported between the proteins involved in establishment and maintenance of silent chromatin in these two distantly related yeasts. Silencing in S.cerevisiae is mediated by Sir2p-containing complexes, whereas silencing in S.pombe is mediated primarily by Swi6-containing complexes. The Swi6 complexes of S.pombe contain proteins closely related to their counterparts in higher eukaryotes, but have no apparent orthologs in S.cerevisiae. Silencing proteins from both yeasts are also actively involved in other chromosome-related nuclear functions, including DNA repair and the regulation of chromatin structure.

Fungal Proteins↗