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Yan Wang

Publications and source records attributed to Yan Wang.

At least 379 records · Page 21Linked to original sources
PubMed2004

Synthetic lethal targeting of MYC by activation of the DR5 death receptor pathway.

The genetic concept of synthetic lethality provides a framework for identifying genotype-selective anticancer agents. In this approach, changes in cellular physiology that arise as a consequence of oncogene activation or tumor suppressor gene loss, rather than oncoproteins themselves, are targeted to achieve tumor selectivity. Here we show that agonists of the TRAIL death receptor DR5 potently induce apoptosis in human cells overexpressing the MYC oncogene, both in vitro and as tumor xenografts in vivo. MYC sensitizes cells to DR5 in a p53-independent manner by upregulating DR5 cell surface levels and stimulating autocatalytic processing of procaspase-8. These results identify a novel mechanism by which MYC sensitizes cells to apoptosis and validate DR5 agonists as potential MYC-selective cancer therapeutics.

Animals↗
PubMed2004

Chromosome walking in the Petunia inflata self-incompatibility (S-) locus and gene identification in an 881-kb contig containing S2-RNase.

Self-incompatibility (SI) in the Solanaceae, Rosaceae and Scrophulariaceae is controlled by the polymorphic S locus, which contains two separate genes encoding pollen and pistil determinants in SI interactions. The S-RNase gene encodes the pistil determinant, whereas the pollen determinant gene, named the pollen S gene, has not yet been identified. Here, we set out to construct an integrated genetic and physical map of the S locus of Petunia inflata and identify any additional genes located at this locus. We first conducted chromosome walking at the S2 locus using BAC clones that contained either S2-RNase or one of the nine markers tightly linked to the S locus. Ten separate contigs were constructed, which collectively spanned 4.4 Mb. To identify additional genes located at the S2 locus, a 328-kb region (part of an 881-kb BAC contig) containing S2-RNase was completely sequenced. Approximately 76% of the region contained repetitive sequences, including transposon-like sequences. Other than S2-RNase, an F-box gene, named PiSLF2 (S2-allele of P. inflata S-locus F-box gene), was the only predicted gene whose deduced amino acid sequence was similar to the sequences of known proteins in the database. Two different cDNA selection methods were used to identify additional genes in the 881-kb contig; 11 groups of cDNA clones were identified in addition to those for S2-RNase and PiSLF2. RT-PCR analysis of expression profiles and PCR analysis of BAC clones and genomic DNA confirmed that seven of these 11 newly identified genes were located in the 881-kb contig.

Chromosome Walking↗
PubMed2004

Gait instability in patients with acoustic neuroma.

OBJECTIVE: To investigate pathological gait in patients with unilateral acoustic neuroma using tactile sensors placed under both feet. MATERIAL AND METHODS: Forty-three patients were enrolled in the study. They were categorized into two groups: the small tumor group had tumors < 2 cm from the porus acousticus without any brainstem compression and the large tumor group had tumors > 2 cm from the porus acousticus with brainstem compression. Eighteen healthy subjects served as controls. Subjects were asked to walk freely with eyes open or closed for a distance of nearly 8 m. The coefficients of variation (CVs) of stance, swing and double support were calculated. The stability of the trajectories of the center of force and the foot pressure difference were also studied. RESULTS: The CVs of stance, swing and double support were significantly greater with eyes closed and, with the exception of double support, these differences were greater in the tumor groups. The instability of the trajectories of the center of force was significantly greater in the tumor group, and in the large tumor group the horizontal component of sway movement of the trajectories of the center of force of the foot on the same side as the lesion was greater than that on the intact side with eyes closed. Regarding foot pressure differences between the two feet, the large tumor group had a greater foot pressure for the foot on the same side as the lesion than for the foot on the intact side, especially with eyes closed. No significant difference was found in the small tumor group. CONCLUSION: The presence of acoustic neuroma may cause unstable gait, and steady gait is considerably dependent on visual input. Larger tumors may produce shifts in the body's center of gravity to the lesioned side during gait, especially under conditions of visual deprivation. These abnormalities may reflect some influences on gait control systems such as phase and muscular tonus control systems.

Gait Disorders, Neurologic↗
PubMed2004

Furostanol oligoglycosides from Asparagus cochinchinensis.

Three new furostanol oligoglycosides, named aspacochioside A (1), B (2) and C (3), together with the known compound 3-O-[(alpha-L-rhamnopyranosyl-(1 --> 4))(beta-D-glucopyranosyl)]-26-O[beta-D-glucopyranosyl]-(25S)-5beta-spirostane-3beta-ol were isolated from the roots of Asparagus cochinchinensis. Their structures were elucidated by spectroscopic techniques (IR, HR-ESIMS, ESIMS/MS, ID and 2D NMR) and chemical methods as 3-O-[(alpha-L-rhamnopyranosyl-(1 --> 4))(beta-D-glucopyranosyl)]-26-O-[beta-D-glucopyranosyl]-(25S)-5beta-furostane-3beta,22alpha,26-triol (1), 3-O-[(alpha-L-rhamnopyranosyl-(1 --> 4))(beta-D-glucopyranosyl)]-26-O-[beta-D-glucopyranosyl]-22alpha-methoxy-(25S)-5beta-furostane-3beta,26-diol (2), and 3-O-[(alpha-L-rhamnopyranosyl-(1 --> 4))(beta-D-glucopyranosyl)]-26-O-[beta-D-glucopyranosyl]-(25S)-5beta-furost-20(22)-en-3beta,26-diol (3).

Asparagus Plant↗
PubMed2004

Multiple peak formation of avidin on an iminobiotin affinity support.

When pure avidin is chromatographed on a homemade iminobiotin column, two distinct peaks are observed using a gradient solvent system starting with a pH 9 buffer. Proteins in both peaks are shown to be identical by nondenatured polyacrylamide gel electrophoretic experiment. The weak interaction of the protein with the stationary phase at pH 9 could cause this unusual behavior.

Avidin↗
PubMed2004

Genome-wide gene expression analysis for induced ischemic tolerance and delayed neuronal death following transient global ischemia in rats.

Genome-wide gene expression analysis of the hippocampal CA1 region was conducted in a rat global ischemia model for delayed neuronal death and induced ischemic tolerance using an oligonucleotide-based DNA microarray containing 8,799 probes. The results showed that expression levels of 246 transcripts were increased and 213 were decreased following ischemia, corresponding to 5.1% of the represented probe sets. These changes were divided into seven expression clusters using hierarchical cluster analysis, each with distinct conditions and time-specific patterns. Ischemic tolerance was associated with transient up-regulation of transcription factors (c-Fos, JunB Egr-1, -2, -4, NGFI-B), Hsp70 and MAP kinase cascade-related genes (MKP-1), which are implicated cell survival. Delayed neuronal death exhibited complex long-lasting changes of expression, such as up-regulation of proapoptotic genes (GADD153, Smad2, Dral, Caspase-2 and -3) and down-regulation of genes implicated in survival signaling (MKK2, and PI4 kinase, DAG/PKC signaling pathways), suggesting an imbalance between death and survival signals. Our study provides a differential gene expression profile between delayed neuronal death and induced ischemic tolerance in a genome-wide analysis, and contributes to further understanding of the complex molecular pathophysiology in cerebral ischemia.

Animals↗
PubMed2004

Kaposi's sarcoma-associated herpesvirus ori-Lyt-dependent DNA replication: cis-acting requirements for replication and ori-Lyt-associated RNA transcription.

Herpesvirus lytic DNA replication requires both the cis-acting element, the origin, and trans-acting factors such as virally encoded origin-binding protein and DNA replication enzymes. Recently, the origins of lytic DNA replication (ori-Lyt) in Kaposi's sarcoma-associated herpesvirus (KSHV) have been identified and a virally encoded bZip protein, K8, has been shown to specifically bind to the origin. To map cis-acting elements within KSHV ori-Lyt that are required for DNA replication function and to define the nature of K8 bZip protein binding to the origin, we constructed consecutive internal deletion mutations across the core domain of a KSHV ori-Lyt and tested them for DNA replication function in a transient replication assay. This mutagenesis study allowed the identification of four components within the ori-Lyt, and all were indispensable for ori-Lyt function. The first component contains eight CCAAT/enhancer binding protein (C/EBP) binding motifs that organize as four spaced C/EBP palindromes. Each palindrome contains two head-to-head CCAAT consensus motifs that are separated by a 13- or 12-bp space sequence. Substitution mutagenesis of these C/EBP motifs showed that these C/EBP palindromes are required for both K8 binding and ori-Lyt-dependent DNA replication. The second component is an 18-bp AT palindrome, which is essential for ori-Lyt function. The third component was determined to be a 32-bp previously unidentified sequence and is required for DNA replication. The last component consists of an open reading frame 50 (ORF50)/Rta responsive element (RRE) and a TATA box. We showed that the binding of an ORF50/Rta protein to the RRE was essential for ori-Lyt-dependent DNA replication. The presence of a functional RRE and a downstream TATA box suggested that this region serves as an ORF50/Rta-dependent promoter and a transcription event may be necessary for ori-Lyt-dependent DNA replication. Using a luciferase reporter system, we demonstrated that the region of the RRE and TATA box constitutes an ORF50/Rta-dependent promoter. Furthermore, a polyadenylated RNA of 1.4 kb was identified downstream of the promoter.

Amino Acid Sequence↗
PubMed2004

Adenovirus-mediated transfer of the 1-cys peroxiredoxin gene to mouse lung protects against hyperoxic injury.

1-Cys peroxiredoxin (1-cysPrx) is a novel antioxidant enzyme that has been shown to reduce a broad spectrum of peroxides including phospholipid hydroperoxides. We tested the hypothesis that adenovirus-mediated transfer of the 1-cysPrx gene can protect lungs of mice from oxidant injury. Mice infected with AdLacZ/AdNull were used as a control (AdCon). X-galactosidase staining revealed widespread expression of the LacZ gene in airways and lung alveoli. Compared with AdCon, 1-cysPrx expression was increased about twofold at 3 days after adenovirus infection. Mice with increased Prx expression showed less loss of body weight and longer survival during exposure to 100% O(2) or to 85% O(2) for 4 days followed by 100% O(2). At 72 h of 100% O(2) exposure, AdPrx infection protected mouse lungs from injury as indicated by less pleural effusion, lower lung wet/dry weight, less protein and fewer nucleated cells in bronchoalveolar lavage fluid, and lower content of thiobarbituric acid-reactive substances and protein carbonyls in lung homogenate. These findings show that increased expression of 1-cysPrx through adenovirus-mediated gene transfer protects mouse lungs from hyperoxic injury and delays death.

Adenoviridae↗
PubMed2004

Three-Dimensional Culture of Hybridoma Cells Secreting Anti-Human Chorionic Gonadotropin by a New Rolling Culture System.

Cell growth rate and production of monoclonal antibody (MAb) of hybridoma cells producing anti-human chorionic gonadotropin (hCG) MAb have been used as investigation criteria in double-mouthed rolling bottle (DMRB). Compared with T-flask cell culture, both of the cell number and MAb production increased by approximately 42.5% when the medium was supplemented with 5% fetal calf serum (FCS) and DMRB rotated at 2 turns per minute. Yield of MAb was experimentally related to the number of viable cells. Interestingly, MAb yield was four times as high as that cultured in T-flask in the first 24 hours, and about 75% yield of total MAb was secreted by 48 hours during the culture. It appears that the promoted cell growth and MAb yield are resulted from the three-dimensional growth of hybridoma cells under a suitably revolving condition.

Journal Article↗
PubMed2004

[Analysis of the association between the quantity of insoluble particles in intravenously administered solution with adverse drug reactions].

OBJECTIVE: To investigate the possible association between adverse drug reactions and the quantity of insoluble particles in the intravenously administered drugs. METHODS: The solutions were prepared following the procedures in routine clinical practice, and the quantity of insoluble particles in these solutions were measured before and after the solutions went through the transfusion apparatus. RESULTS: The quantity of insoluble particles measured after the solutions passed through the transfusion apparatus was consistent with the standard documented in Chinese Pharmacopoeia. CONCLUSION: Adverse intravenous reactions occurring in our hospital has no association with excessive quantity of insoluble particles in the administered drugs.

Drug-Related Side Effects and Adverse Reactions↗
PubMed2004

[Amplification and cloning of the N gene of SARS-associated coronavirus].

OBJECTIVE: To amplify and clone the N gene of severe acute respiratory syndrome-associated coronavirus. METHOD: Using primer Premier 5.0 software, two pairs of nested PCR primers were designed to amplify the N gene. After purification, the amplified products were cloned into pMD18-T vectors, and the positive clones with the inserted fragments were identified by sequence analysis. RESULTS: The amplified products was about 1 375 bp in length, and sequence analysis demonstrated that the N gene fragments had been successfully inserted into pMD18-T vectors. CONCLUSION: The successful amplification and cloning of N gene facilitates further investigation of the expression of the N protein and study of its structure and functions.

Base Sequence↗
PubMed2004

Design and preparation of oligonucleotide microarray for vaccinia virus detection.

OBJECTIVE: To study the preparation of oligonucleotide microarray for detecting vaccinia virus. METHODS: Oligonucleotide probes were designed and synthesized according to the specific genes of vaccinia virus. Sample DNA of the virus and the negative control sample were obtained and labeled by restriction display technique, followed by hybridization to the oligonucleotide microarray and scanned by Agilent scanner. RESULTS: Strong hybridization signals were detected from the viral DNA hybridized with the microarray, but were absent in the negative sample when positive probes were not used. CONCLUSION: Distinct differences in the hybridization signals between the virus sample and negative sample and between the samples obtained in different phase of infection demonstrate high specificity and sensitivity of the microarray for vaccinia virus detection.

Base Sequence↗
PubMed2004

Effects of temperature on UV-B-induced DNA damage and photorepair in Arabidopsis thaliana.

DNA damage in the form of cyclobutane pyrimidine dimers(CPDs) and (6-4) photoproducts(6-4PPs) induced by UV-B radiation in Arabidopsis thaliana at different temperatures was investigated using ELISA with specific monoclonal antibodies. CPDs and 6-4PPs increased during 3 h UV-B exposure, but further exposure led to decreases. Contrary to the commonly accepted view that DNA damage induced by UV-B radiation is temperature-independent because of its photochemical nature, we found UV-B-induction of CPDs and 6-4PPs in Arabidopsis to be slower at a low than at a high temperature. Photorepair of CPDs at 24 degrees C was much faster than that at 0 degrees C and 12 degrees C, with 50% CPDs removal during 1 h exposure to white light. Photorepair of 6-4PPs at 12 degrees C was very slow as compared with that at 24 degrees C, and almost no removal of 6-4PPs was detected after 4 h exposure to white light at 0 degrees C. There was evidence to suggest that temperature-dependent DNA damage and photorepair could have important ecological implications.

Arabidopsis↗
PubMed2004

[Circulating endothelial cells and hepatocyte growth factor in patients with pregnancy induced hypertension].

OBJECTIVE: To investigate the relationship between hepatocyte growth factor (HGF) and vascular endothelial cells (VEC) in pregnancy induced hypertension (PIH). METHODS: Twenty women with PIH (6 mild, and 14 moderate or severe PIH) and 20 women with normal pregnancy were recruited as study group and control group, respectively. The two groups were matched in maternal age, parity and gestational age. Flow cytometer was used for counting the number of peripheral blood circulating endothelial cells (CEC), while enzyme-linked immunoabsorbent assay (ELISA) was used to measure the concentration of serum HGF. RESULTS: In the study group, the concentration of HGF was (1395 +/- 512) ng/L, and the number of CEC was (109,360 +/- 24,070) /L. In the control group, the concentration of HGF was (1565 +/- 399) ng/L, and the number of CEC was (21,800 +/- 4420)/L. The differences both in the concentration of HGF and the number of CEC between the two groups were statistically significant (P < 0.01). Negative correlation between CEC and HGF was found both in study group and control group (r = -0.608, P < 0.01). CONCLUSION: Decreased HGF may be related to VEC damage in the development of PIH.

Adult↗
PubMed2004

Role of 1,25-dihydroxyvitamin D3 in preventing acute rejection of allograft following rat orthotopic liver transplantation.

BACKGROUND: We investigated the role of 1,25-dihydroxyvitamin D3(1,25-(OH)2D3) in preventing allograft from acute rejection following orthotopic liver transplantation. METHODS: A rat orthotopic liver transplantation model was used in this study. SD-Wistar rats served as a high responder strain combination. Recipients were subjected to administration of 1,25-(OH)2D3 at dosages ranging from 0.25 microg.kg(-1).d(-1) to 2.5 microg.kg(-1).d(-1). Survival after transplantation as well as pathological rejection grades and IFN-gamma mRNA, IL-10 mRNA transcription intragraft on day 7, and day 30 post-transplantation were observed. RESULTS: After recipients were treated with 1,25(OH)2D3 at dosages of 0.5 microg.kg(-1).d(-1) or 1.0 microg.kg(-1).d(-1), survivals of recipients were prolonged. Ninety-five percent confidence intervals of survival were 46 - 87 days and 69 - 102 days (both P = 0.0005 vs control group), respectively. On day seven post-transplantation, relative levels of IFN-gamma mRNA transcription were 0.59 +/- 0.12 and 0.49 +/- 0.16, which was higher than the control group (P = 0.005, P = 0.003, respectively). Relative levels of IL-10 mRNA transcription were 0.83 +/- 0.09 and 0.76 +/- 0.09, which was lower than the control group (P = 0.002, P = 0.003, respectively). At a dosage of 0.5 microg.kg(-1).d(-1), the median of pathological rejection grade on day seven and on day thirty post-transplantation were 1.5 and 2.0 in comparison with the CsA-treated group (P = 0.178, P = 0.171, respectively). At a dosage of 0.5 microg.kg(-1).d(-1), the median of pathological rejection grade on day seven and day thirty post-transplantation were 1.5 and 1.5 in comparison with CsA-treated group (P = 0.350, P = 0.693, respectively). CONCLUSION: After each recipient was treated with 1,25-(OH)2D3 at a dosage of (0.5 - 1.0) microg.kg(-1).d(-1), transcription of cytokine intragraft was accommodated effectively and deviated to Th2 type, resulting in alleviation of acute rejection. 1,25-(OH)2D3 can prolong survival of recipient after orthotopic liver transplantation.

Animals↗
PubMed2004

[Psychiatric and central nervous system involvement in Sjogren's syndrome].

OBJECTIVE: To study psychiatric features and the manifestations of central nervous system involvement in Chinese patients with primary Sjogren's syndrome (PSS). METHODS: The Minnesota Multiphasic Personality Inventory (MMPI) was used to study 27 PSS female patients and 57 healthy women. The results from two groups were compared. Ten SS patients were evaluated by electroencephalography (EEG), transcranial doppler ultrasound (TCD) and magnetic resonance imaging (MRI). RESULTS: Of 27 patients tested, the three highest clinical mean scales included Hypochondriasis (Hs), Hysteria (Hy), Psychasthenia (Pt) were found. When PSS group was compared with normal control, T scores of SS patients were significantly higher than the healthy women in Hs, Hy. Abnormal EEG was found in 3 of 9 PSS patients. TCD was abnormal in 5 of 9 patients. MRI in 1 patient showed abnormality. CONCLUSIONS: This study shows that the personality of PSS patients is abnormal, the features are neuroticism. Central nervous system was markedly involved in Chinese patients with PSS, including abnormal EEG and TCD. The changes of central nervous system may be related to abnormalities of psychiatric changes.

Adult↗
PubMed2004

[Research advances on tumor therapy via nitric oxide].

Nitric oxide (NO) is a short-lived pleiotropic molecule involved in many physiological and pathological processes in the organism. As an important biologic mediator, nitric oxide has been focused in tumor study and therapy for its function in the process of tumor genesis, progression,and death. It is documented that nitric oxide plays a dual role:induction or suppression of tumorigenesis, which is dependent on different conditions, such as the concentration, time,and position of NO products. Tumor growth can be promoted by continuous low NO concentration, while cytotoxicity and apoptosis to tumor cells can be induced by quite high NO concentration. Currently, the concentration-dependent principle is the theoretical basis of tumor therapy mediated by NO. These tumor therapies can be classified into several types: firstly, drug treatments including chemotherapy, nitric oxide synthase inducer and inhibitor, together with related research from Chinese traditional medicine; secondly, radiotherapy and photodynamic therapy; thirdly, genic level therapy; and so on. Thus, the paper states the relationship and mechanism between NO and tumor, and summarizes research advances on tumor therapy via nitric oxide.

Animals↗