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Tong Zhang

Publications and source records attributed to Tong Zhang.

At least 55 records · Page 3Linked to original sources
PubMed2005

Identification of the sequence determinants mediating the nucleo-cytoplasmic shuttling of TIAR and TIA-1 RNA-binding proteins.

TIAR and TIA-1 are two closely related RNA-binding proteins which possess three RNA recognition motifs (RRMs) followed by an auxiliary region. These proteins are involved in several mechanisms of RNA metabolism, including alternative hnRNA splicing and regulation of mRNA translation. Here we characterize the subcellular localization of these proteins in somatic cells. We demonstrate that TIAR and TIA-1 continuously shuttle between the cytoplasm and the nucleus and belong to the class of RNA-binding proteins whose nuclear import is transcription-dependent. We identified RRM2 and the first half of the auxiliary region as important determinants for TIAR and TIA-1 nuclear accumulation. In contrast, the nuclear export of TIAR and TIA-1 is mediated by RRM3. Both RRMs contribute to TIAR and TIA-1 nuclear accumulation or export by their RNA-binding capacity. Indeed, whereas mutations of the highly conserved RNP2 or RNP1 peptides in RRM2 redistribute TIAR to the cytoplasm, similar modifications in RRM3 abolish TIAR nuclear export. Moreover, TIAR and TIA-1 nuclear accumulation is a Ran-GTP-dependent pathway, in contrast to its nuclear export which is unaffected by Ran-GTP depletion and which is independent of the major CRM1-exporting pathway. This study demonstrates the importance of TIAR and TIA-1 RNA-binding domains for their subcellular localization and provides the first evidence for distinct functions of TIAR and TIA-1 RRMs.

Active Transport, Cell Nucleus↗
PubMed2005

Effect of pH change on the performance and microbial community of enhanced biological phosphate removal process.

An acetate-rich wastewater, containing 170 mg/L of total organic carbon (TOC), 13 mg/L of N, and 15 mg/L of P, was treated using the enhanced biological phosphate removal (EBPR) process operated in a sequencing batch reactor. A slight change of pH of the mixed liquor from 7.0 to 6.5 led to a complete loss of phosphate-removing capability and a drastic change of microbial populations. The process steadily removed 94% of TOC and 99.9% of P from the wastewater at pH 7.0, but only 93% TOC and 17% of P 14 days after the pH was lowered to pH 6.5. The sludge contained 8.8% P at pH 7.0, but only 1.9% at pH 6.5. Based on 16S rDNA analysis, 64.8% of the clones obtained from the sludge at pH 7.0 were absent in the pH 6.5 sludge. The missing microbes, some of which were likely responsible for the phosphate removal at pH 7.0, included beta-Proteobacteria, Actinobacteria, Bacteriodetes/Chlorobi group, plus photosynthetic bacteria and Defluvicoccus of the alpha-Proteobacteria. Among them, the last two groups, which represented 9.3% and 10.1% of the EBPR sludge at pH 7.0, have rarely been reported in an EBPR system.

Bacteria↗
PubMed2005

FDG-PET and CT characterization of adrenal lesions in cancer patients.

PURPOSE: Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) may differentiate benign from malignant adrenal lesions. In this study, standardized uptake values (SUVs), visual interpretation, and computed tomography (CT) data were correlated with the final diagnosis to determine the contribution of adrenal FDG-PET in patients with known non-adrenal cancer. METHODS: Ninety-two patients with adrenal lesions on CT underwent FDG-PET. Eighty adrenals in 74 patients met the inclusion criteria (PET scan within 4 weeks of CT plus >1 year of follow-up after PET scan with repeat CT or biopsy for final diagnosis). CT was considered positive for metastases (CT+) based on two of the following three criteria: >4 cm, Hounsfield units (HU) >30, and delayed contrast enhancement. Lesions with <2 cm, with HU <20, and showing no enhancement were considered benign (CT-). Remaining lesions were considered indeterminate (CT-Ind). Visually, adrenal uptake exceeding liver uptake was considered PET positive (PET+). Diagnosis of metastases was based on biopsy or interval CT growth (unchanged >1 year=benign). SUV(max) and SUV(avg) were calculated from a 4 x 4 pixel region of interest drawn from CT, PET, and fused images. A receiver operator curve (ROC) determined the SUV with the best sensitivity and specificity. RESULTS: Overall, PET was 93% sensitive and 96% specific for metastases. A SUV(max) of 3.4 was 95% sensitive and 86% specific. A SUV(avg) of 3.1 was 95% sensitive and 90% specific. There was no significant difference between visual interpretation and SUV (SUV(max) or SUV(avg)). Among CT+ and CT- lesions, PET was 100% sensitive and 96% specific; CT was 86% sensitive and 100% specific. In the CT-Ind group, PET was 88% sensitive and 96% specific. CONCLUSION: PET accurately characterized adrenal lesions. Visual interpretation was as accurate as SUV. FDG-PET was most useful in the 52.5% of cancer patients with inconclusive adrenal lesions on CT.

Adrenal Gland Neoplasms↗
PubMed2005

Poly(ADP-ribosyl)ation by PARP-1: 'PAR-laying' NAD+ into a nuclear signal.

Poly(ADP-ribose) (PAR) and the PAR polymerases (PARPs) that catalyze its synthesis from donor nicotinamide adenine dinucleotide (NAD+) molecules have received considerable attention in the recent literature. Poly(ADP-ribosyl)ation (PARylation) plays diverse roles in many molecular and cellular processes, including DNA damage detection and repair, chromatin modification, transcription, cell death pathways, insulator function, and mitotic apparatus function. These processes are critical for many physiological and pathophysiological outcomes, including genome maintenance, carcinogenesis, aging, inflammation, and neuronal function. This review highlights recent work on the biochemistry, molecular biology, physiology, and pathophysiology of PARylation, focusing on the activity of PARP-1, the most abundantly expressed member of a family of PARP proteins. In addition, connections between nuclear NAD+ metabolism and nuclear signaling through PARP-1 are discussed.

Aging↗
PubMed2005

Optimization of the chiral separation of a Ca-sensitizing drug on an immobilized polysaccharide-based chiral stationary phase: case study with a preparative perspective.

Sample solubility in the mobile phase and enantioselectivity are key factors in chiral preparative chromatography. In the search for a high throughput process for production of pure enantiomers, the rational design of the mobile phase and the selection of a suitable chiral stationary phase (CSP) are essential. However, one may sometimes be faced with the incompatibility between the CSP and the preferential eluent for sample solubility. Such a limitation may be circumvented by using an immobilized CSP such as CHIRALPAK IA. In this manuscript, the chiral separation of a Ca-sensitizing drug (EMD 53986) is optimized on CHIRALPAK IA in terms of sample solubility, enantioselectivity and preparative productivity. The approaches for method optimization and the impact of sample solubility on productivity are discussed. The preparative potential of CHIRALPAK IA is also demonstrated.

Amylose↗
PubMed2005

Erlotinib in lung cancer - molecular and clinical predictors of outcome.

BACKGROUND: A clinical trial that compared erlotinib with a placebo for non-small-cell lung cancer demonstrated a survival benefit for erlotinib. We used tumor-biopsy samples from participants in this trial to investigate whether responsiveness to erlotinib and its impact on survival were associated with expression by the tumor of epidermal growth factor receptor (EGFR) and EGFR gene amplification and mutations. METHODS: EGFR expression was evaluated immunohistochemically in non-small-cell lung cancer specimens from 325 of 731 patients in the trial; 197 samples were analyzed for EGFR mutations; and 221 samples were analyzed for the number of EGFR genes. RESULTS: In univariate analyses, survival was longer in the erlotinib group than in the placebo group when EGFR was expressed (hazard ratio for death, 0.68; P=0.02) or there was a high number of copies of EGFR (hazard ratio, 0.44; P=0.008). In multivariate analyses, adenocarcinoma (P=0.01), never having smoked (P<0.001), and expression of EGFR (P=0.03) were associated with an objective response. In multivariate analysis, survival after treatment with erlotinib was not influenced by the status of EGFR expression, the number of EGFR copies, or EGFR mutation. CONCLUSIONS: Among patients with non-small-cell lung cancer who receive erlotinib, the presence of an EGFR mutation may increase responsiveness to the agent, but it is not indicative of a survival benefit.

Adenocarcinoma↗
PubMed2005

Solvent versatility of immobilized 3,5-dimethylphenylcarbamate of amylose in enantiomeric separations by HPLC.

CHIRALPAK IA is a new chiral stationary phase containing amylose 3.5-dimethylphenylcarbamate immobilized onto silica gel. It is compatible with the whole range of organic solvents. Its solvent versatility has been thoroughly investigated. The option to use a wide range of solvents, especially the "non-standards" ones, in the mobile phase enables the enhancement of chiral separation methods in terms of enantioselectivity, resolution, analysis time, sample injection and sample solubility. Parameters such as the mobile phase type, the nature of modifier and eluting strength of various solvents are examined and discussed. A guideline for method development and optimization on CHIRALPAK IA is also proposed.

Amylose↗
PubMed2005

Chimeric NK-receptor-bearing T cells mediate antitumor immunotherapy.

NKG2D is an activating cell-surface receptor expressed on natural killer (NK) cells and some T-cell subsets. Its ligands are primarily expressed on tumor cells. The aim of this study was to determine whether chimeric NK-receptor-bearing T cells would directly kill tumor cells and lead to induction of host immunity against tumors. Chimeric NK receptors were produced by linking NKG2D or DNAX activating protein of 10 kDa (Dap10) to the cytoplasmic portion of the CD3zeta chain. Our results showed that chimeric (ch) NKG2D-bearing T cells responded to NKG2D-ligand-bearing tumor cells (RMA/Rae-1beta, EG7) but not to wild-type tumor cells (RMA). This response was dependent upon ligand expression on the target cells but not on expression of major histocompatibility complex (MHC) molecules, and the response could be blocked by anti-NKG2D antibodies. These T cells produced large amounts of T-helper 1 (Th1) cytokines and proinflammatory chemokines and killed ligand-expressing tumor cells. Adoptive transfer of chNKG2D-bearing T cells inhibited RMA/Rae-1beta tumor growth in vivo. Moreover, mice that had remained tumor-free were resistant to subsequent challenge with the wild-type RMA tumor cells, suggesting the generation of immunity against other tumor antigens. Taken together, our findings indicate that modification of T cells with chimeric NKG2D receptors represents a promising approach for immunotherapy against cancer.

Animals↗
PubMed2005

Antigen epitope-expressing cytokines for DNA immunization.

Strategies to enhance the efficacy of DNA vaccination against malignancy remain to be established. In this study, a plasmid expressing a tumor antigen incorporated into the signal peptide of human IL-2 was tested as a DNA vaccine in a murine model system. Results showed that antigen-specific CTL responses were elicited by intramuscular injection of these plasmids. Importantly, compared with a minigene vector expressing the same epitope, the OVA epitope-incorporated, IL-2 expression plasmid vaccination was more effective in protecting mice from OVA-expressing tumor challenge. The improved efficacy appears to result from enhanced antigen presentation as well as the immunostimulatory activity of IL-2. This approach may provide new perspectives in designing cytokine-adjuvant DNA vaccines for clinical applications.

Animals↗
PubMed2005

Immuno-gene therapy of melanoma by tumor antigen epitope modified IFN-gamma.

Cytokine-based vaccines play a major part in tumor immuno-gene therapy. However, down-regulated antigen expression on tumor cells may diminish the immuno-potentiating aspects of cellular vaccines. In this study, we coexpressed a tumor antigen epitope with IFN-gamma in the same gene by replacing the IFN-gamma signal peptide with an antigen epitope-expressing signal peptide. We then investigated the effect of the antigen epitope-incorporated IFN-gamma on the immunotherapy of murine melanoma B16 tumors. Results showed that TRP-2 epitope-expressing IFN-gamma decreased B16 tumorigenicity and enhanced its immunogenicity after gene transfer. Protective immunity against wild type B16 tumors was induced by vaccination with IFN-gamma transiently gene-modified tumor cells. These data suggest that cellular vaccines engineered to express an antigen epitope within an immunostimulatory cytokine could potentiate the immunization effect.

Animals↗
PubMed2005

Microbial community analysis and performance of a phosphate-removing activated sludge.

The microbial community of a phosphate-removing activated sludge was analyzed according to the extracted 16S rDNA sequences. The sludge, which accumulated 5.6% P by weight, was obtained from a sequencing batch reactor treating a fatty-acid rich wastewater containing 108 mg l(-1) total organic carbon (TOC), 14.0 mg l(-1) N and 16.2 mg l(-1) P. The reactor at 25 degrees C and pH 7.6 removed over 96% TOC and 99.9% P from the wastewater. According to the 16S rDNA analysis of the 114 clones developed, the sludge had a diverse population, mainly comprising Proteobacteria (71.0%) and the Cytophaga Flavobacterium Bacteroides group (23.7%), plus a few species of Planctomycetales (2.6%), Verrucomicrobiales (1.8%) and Firmicutes (0.9%). Of the 114 clones, 36 (31.6%) were closely affiliated with Acinetobacter. However, Acinetobacter did not accumulate phosphate judging from the images of sludge samples hybridized with an Acinetobacter-specific probe and stained with a phosphate-specific dye. The identities of the phosphate-removing bacteria remain unclear.

Bacteria↗
PubMed2005

X-ray single-crystal analysis of (-)-(S)-equol isolated from rat's feces.

The biological effects of soy isoflavones have attracted considerable interest in recent years, leading to numerous studies on dietary intake and epidemiology. (-)-(S)-equol (3) is a metabolite produced in vivo from the isoflavone daidzein, a kind of soy phytoestrogen, by the action of gut microflora. It has higher biological activity than its precursor. Here, we wish to report the isolation and first X-ray crystal structure of 3 from the feces of rats fed a soy-isoflavone-containing diet.

Animals↗
PubMed2005

Microbial community and biochemistry process in autosulfurotrophic denitrifying biofilm.

The 16S rDNA-based molecular technique was applied to analyze the microbial community of autotrophic denitrification bacteria in a biofilm developed on the surface of sulfur particles and then the biochemistry process involved in this biofilm was discussed based on the microbial community analysis. Six key operational taxonomy units were identified, which were all unknown species belonging to a wide range of bacteria from four major subdivisions (alpha, beta, gamma and delta) of the kingdom Proteobacteria and from the kingdom Chlorobia (green sulfur bacteria). One species was chemoautotrophic and related to Thiobacillus denitrificans, two species were photoautotrophic, and three were chemoheterotrophic. Contrary to expectation, T. denitrificans-like bacteria constituted only 32% of the microbial community. As a result of the study, the entire microbiology of the autosulfurotrophic denitrification process as well as the interactions between the different microbial groups in the biofilm may need to be reconsidered.

Biofilms↗
PubMed2005

Sutural distraction osteogenesis (SDO) versus osteotomy distraction osteogenesis (ODO) for midfacial advancement: a new technique and primary clinical report.

A new technique of osteotomy distraction osteogenesis (ODO) and sutural distraction osteogenesis (SDO) by the use of bone-borne traction hooks is presented. The technique of osteotomy plus distraction osteogenesis is suitable for adult patients. The technique of sutural distraction osteogenesis is suitable for young patients, ages 6 through 12 years. The distraction system consists of a face-bow, orthodontic elastics, and bone-borne traction hooks. The bone-borne traction hooks are made of titanium, with two traction hooks running laterally or downwardly. When a Le Fort III osteotomy is needed, bone-borne traction hooks are inserted through the nostrils into a bone hole drilled at the lateral-inferior pyriform aperture. When no osteotomy is needed, only the bone-borne traction hooks are placed. Heavy elastics were used in the technique of osteotomy distraction osteogenesis for Le Fort III osteotomy adult patients, whereas light forces and thus light elastics were used for younger patients. Three adult patients and four children were treated by osteotomy distraction and sutural distraction, respectively. All seven patients with midfacial hypoplasia established a harmonious facial profile and normal occlusal relationships. Radiographic examination showed balanced advancement of the midfacial skeleton. It is suggested that the treatment of midfacial hypoplasia in children by the technique of sutural distraction osteogenesis is to be preferred because of its simplicity and relative noninvasiveness. Thus, the authors suggest that midfacial hypoplasia should be treated at a younger age by this technique, potentially eliminating the need for a Le Fort III osteotomy at an older age.

Adolescent↗
PubMed2005

Learning bounds for kernel regression using effective data dimensionality.

Kernel methods can embed finite-dimensional data into infinite-dimensional feature spaces. In spite of the large underlying feature dimensionality, kernel methods can achieve good generalization ability. This observation is often wrongly interpreted, and it has been used to argue that kernel learning can magically avoid the "curse-of-dimensionality" phenomenon encountered in statistical estimation problems. This letter shows that although using kernel representation, one can embed data into an infinite-dimensional feature space; the effective dimensionality of this embedding, which determines the learning complexity of the underlying kernel machine, is usually small. In particular, we introduce an algebraic definition of a scale-sensitive effective dimension associated with a kernel representation. Based on this quantity, we derive upper bounds on the generalization performance of some kernel regression methods. Moreover, we show that the resulting convergent rates are optimal under various circumstances.

Artificial Intelligence↗
PubMed2005

[Analysis on the relative factors of trichomonal vaginitis in married childbearing age women in rural impoverished area].

OBJECTIVE: To investigate the status and relative factors of trichomonal vaginitis among married childbearing age women in rural impoverished area of the northwestern part of China and hence identify the risk factors and provide a basis for the prevention and treatment of trichomonal vaginitis. METHODS: Questionnaire investigation, gynecological and laboratory examination were carried out in 480 women who had been selected by multi-stage cluster sampling in rural impoverished area of Bao Ji in ShannXi province. A case-control study was conducted to analyze the relative factors of trichomonal vaginitis and other reproductive tract infection (RTI) complications. RESULTS: The prevalence rate of trichomonal vaginitis was 12.9%, and 64.5% of the cases were complicated with chronic cervicitis, 17.7% were complicated with adnexitis. Uni-variated and multi-variated logistic regression analyses revealed that lack of reproductive health knowledge, bath with polluted water, washing vulva or penis with polluted water before sexual intercourse, having intercourse during menstrual period, having past history of trichomonal vaginitis, as well as no-income woman's and husband's negative attitude towards wife's RTIs were risk factors of trichomonal vaginitis and complicating chronic cervicitis or adnexitis. And lack of reproductive health knowledge, bath with polluted water, washing penis with polluted water before sexual intercourse, past history of trichomonal vaginitis, husband's negative attitude to wife's RTIs were relative factors of trichomonal vaginitis and complicating chronic cervicitis or adnexitis revealed by the binary logistic regression analysis. The less score of reproductive health knowledge, the more risk of suffering from trichomonal vaginitis complicating chronic cervicitis. CONCLUSION: Compositive and successive prevention and treatment scheme should be used to control trichomonal vaginitis and other RTI complications in rural impoverished area of northwestern China. The scheme should be focused on four ways, including improving sanitation behaviors in couples, insisting on normative treatment, generalizing reproductive health knowledge and mobilizing husbands to pay attention.

Adult↗