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Biomedical subjects

Ye Zhang

Publications and source records attributed to Ye Zhang.

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

[Application of supraomohyoid neck dissection in oral squamous cell carcinoma with clinically N0 neck].

OBJECTIVES: The value of supraomohyoid neck dissection used in treating oral squamous cell carcinoma was discussed. METHODS: Twenty-seven cN0 patients with oral squamous cell carcinoma were entered into the study. Supraomohyoid neck dissection was performed to remove the lymphatic tissue of level I, II, and III. The operation duration and shoulder function were recorded. RESULTS: The average operation duration was (1.6 +/- 0.2) h. Nineteen percent (5/27) of the cN0 neck were proved positive pathologically which included two cases in level I and four in level II (one case had both level I and II metastases). Shoulder function recovered in three months after operation. All patients were followed up from two years to four years and none of them had local or neck recurrence. CONCLUSIONS: Supraomohyoid neck dissection is a right choice for cN0 patients with oral squamous cell carcinoma with its advantages in both curing neck lymphatic metastases and preserving neck and shoulder contours and functions.

Adult↗
PubMed2004

Repression of hsp90beta gene by p53 in UV irradiation-induced apoptosis of Jurkat cells.

Tumor suppressor p53 has been implicated in cell stress response and determines cell fate of either growth arrest or apoptosis. Heat shock proteins (Hsps) expressed under stress usually confer survival protection to the cell or interruption in the apoptotic pathways. Although Hsp90 can physically interact with p53, whether or not the hsp90 gene is influenced downstream of p53 in UV irradiation-induced apoptosis remains unclear. We have found that the level of p53 is elevated with the decline of Hsp90 in UV-irradiated cells and that malfunction of Hsp90, as inhibited by geldanamycin, enhances the p53-involved UV irradiation-induced apoptosis. In addition, the expression of the hsp90beta gene was reduced in both UV-irradiated and wild type p53-transfected cells. These results suggest a negative correlation between the trans factor p53 and a chaperone gene hsp90beta in apoptotic cells. Mutation analysis demonstrated that the p53 binding site in the first exon was indispensable for p53 regulation on the hsp90beta gene. In addition, with p53 bound at the promoter of the hsp90beta gene, mSin3a and p300 were differentially recruited in UV irradiation-treated or untreated Jurkat cells in vivo. The evidence of p53-repressed hsp90beta gene expression in UV-irradiated cells shed light on a novel pathway of Hsp90 in the survival control of the stressed cells.

Antibiotics, Antineoplastic↗
PubMed2004

Structure analysis and expressions of a novel tetratransmembrane protein, lysosoma-associated protein transmembrane 4 beta associated with hepatocellular carcinoma.

AIM: To analyze the structure and expressions of the protein encoded by an HCC-associated novel gene, lysosome-associated protein transmembrane 4 beta (LAPTM4B). METHODS: Primary structure and fundamental characteristics of LAPTM4B protein were analysed with bioinformatics. Expressions of LAPTM4B in HCC tissues and various cell lines were detected using polyclonal antibodies and Western blot. RESULTS: LAPTM4B encoded two isoforms of proteins with molecular masses 35-ku and 24-ku, respectively. The expression level of LAPTM4B-35 protein in HCC tissues was dramatically upregulated and related to the differentiation status of HCC tissues, and it was also high in some cancer cell lines. Computer analysis showed LAPTM4B was an integral membrane protein with four transmembrane domains. LAPTM4B showed relatively high homology to LAPTM4A and LAPTM5 in various species. CONCLUSION: LAPTM4B gene encoded two isoforms of tetratransmembrane proteins, LAPTM4B-35 and LAPTM4B-24. The expression of LAPTM4B-35 protein is upregulated and associated with poor differentiation in human HCC tissues, and also at high levels in some cancer cell lines. LAPTM4B is an original and conserved protein.

Amino Acid Sequence↗
PubMed2004

The role of lipid charge density in the serum stability of cationic lipid/DNA complexes.

To evaluate the role of lipid charge density in the serum stability of DOTAP-Chol/DNA complexes (lipoplexes), lipid-DNA interactions, extent of aggregation, supercoil content, and in vitro transfection efficiency of lipoplexes were investigated. In general, higher serum concentration destabilized, and increasing molar charge ratio of DOTAP to negatively charged phosphates in the DNA (DOTAP(+)/DNA(-)) stabilized lipoplexes in serum as assessed by the criteria used in this study. The increase of cholesterol content led to increased serum stability, and DOTAP:Chol (mol/mol 1:4)/DNA lipoplex with DOTAP(+)/DNA(-) ratio 4 was the most serum stable formulation of all the formulations examined, and maintained lipid-DNA interactions, did not aggregate and exhibited high in vitro transfection efficiency in 50% (v/v) serum. The increased stability of this formulation could not be explained by the decreased charge density of the lipid component. Furthermore, no single parameter examined in the study could be used to consistently predict the in vitro transfection efficiency of lipoplexes in serum. Surprisingly, no correlation between the maintenance of supercoiled DNA content and in vitro transfection efficiency was found in the study.

Animals↗
PubMed2004

Upregulated expression of neuronal nitric oxide synthase by insulin in both neurons and astrocytes.

Both insulin and nitric oxide (NO) play important roles in the brain. However, there are no unequivocal evidences pointing to a direct effect of insulin on nitric oxide pathway in the brain. In the present study, the effects of insulin on the expression and activity of neuronal nitric oxide synthase (nNOS) were investigated in the cultured cerebellum cell line R2, cerebral cortical astrocytes, and neurons of rats by using flow cytometry, in situ hybridization, RT-PCR, and electron spin resonance (ESR) techniques. In astrocytes, the expression of nNOS was significantly stimulated by insulin in a concentration-dependent manner, with a maximal increase of about 47.6% compared with the control values (p<0.05, t test, n=5). Furthermore, in situ hybridization analysis showed that the expression of nNOS was also significantly increased by insulin (0.64 ng/ml, 6 h), reaching 134.2+/-9.6% of the control values (p<0.05, t test, n=3). In addition, by using nNOS specific primers, RT-PCR analysis also demonstrated the same effect of insulin (0.64 ng/ml, 6 h) on nNOS mRNA expression. Similarly, significant increase of the expression of nNOS protein and mRNA were also observed in both R2 cells and neurons of rats after incubation with insulin. In addition, significant increase of the activity of nNOS in R2 cells and astrocytes were also detected after incubation with insulin (0.64 ng/ml, 9 h) by using ESR technique. Overall, our results suggested that exogenous insulin could upregulate the expression and activity of nNOS in R2 cells, cerebral cortical astrocytes, and neurons of rats. The phenomena opened new insights for further investigation of the physical and pathological significances of insulin in the brain.

Animals↗
PubMed2004

Evidence of nuclear localization of neuronal nitric oxide synthase in cultured astrocytes of rats.

With immunocytochemistry, we have observed the nuclear localization of neuronal nitric oxide synthase (nNOS) in cultured cerebral cortical astrocytes of rats. During the early six days in the subcultures of these cells, nNOS-immunoreactivity was mainly distributed in the cytoplasm. However, nNOS-immunoreactivity was mainly distributed in the nucleus at day 7, and this nuclear localization lasted about ten hours. Meanwhile, inducible nitric oxide synthase expression was significantly inhibited in these cells. Thereafter, nNOS-immunoreactivity was mainly distributed in the cytoplasm again. By confocal microscopy and western blot analysis, the phenomenon of nNOS nuclear localization was further confirmed; and the activity of nNOS in nuclear protein extracts from astrocytes of day 7-subculture could be detected using electron spin resonance (ESR) technique. These results may represent a new pathway of nitric oxide/nNOS participating in inducible nitric oxide synthase gene transcription regulation.

Animals↗
PubMed2004

Phosphorylation of histone H2A inhibits transcription on chromatin templates.

The regulation of gene expression via the histone code has, for the most part, revealed that histone modifications cause the recruitment of adaptor proteins that indirectly regulate the synthesis of RNA. Using purified factors to assemble and modify the chromatin and to transcribe the DNA, we investigated whether modifications of histones may directly impact the RNA polymerase II transcription process. We screened proteins known to modify histones for effects on transcription, and we found that the mitogen- and stress-induced kinase, MSK1, inhibited RNA synthesis. Inhibition of transcription by MSK1 was most sensitive when the template was in chromatin, as naked DNA templates were resistant to the effects of MSK1. We found that MSK1 phosphorylated histone H2A on serine 1, and mutation of serine 1 to alanine blocked the inhibition of transcription by MSK1. Furthermore, we found that acetylation of histone H3 by the p300 and CREB-binding protein associated factor, PCAF, suppressed the kinase-dependent inhibition of transcription. These results suggest that acetylation of histones may stimulate transcription by suppressing an inhibitory phosphorylation by a kinase as MSK1.

Chromatin↗
PubMed2004

Neutral, acidic, and basic derivatives of anthranilamide that confer different formal charge to reducing oligosaccharides.

To facilitate the use of oligosaccharides as analytical tools in biological studies, we have designed, synthesized, and conjugated to maltosaccharides a novel series of homologous small fluorescent moieties that differ in formal charge. These moieties are amide derivatives of anthranilic acid: uncharged N-(2-aminobenzoyl)glycinamide (ABGlyAmide; 2), acidic N,N-dimethyl-N(')-(2-aminobenzoyl)ethylenediamine (ABGlyDIMED; 3), and basic N-(2-aminobenzoyl)glycine (ABGly; 1). Routes for synthesis and optimal reaction conditions for glycoconjugation by conventional reductive amination are presented, as is the compatibility of these adducts with common analytical and preparative chromatographic methods, including RP-HPLC and HPAEC-PAD. These novel anthranilic acid derivatives confer both fluorescence and defined charge to oligosaccharides, and so enhance the repertoire of chromatographic and analytical methods for which anthranilic acid can be used. Furthermore, because glucosaccharides have rigid solution structure, these small fluorescent adducts with different formal charge are ideal tools for molecular sizing studies of membrane pores.

Acids↗
PubMed2004

Low nuclear levels of nuclear factor-kappa B are essential for KC self-induction in astrocytes: requirements for shuttling and phosphorylation.

Stimulation with the chemokine KC induces an autocrine response in mouse astrocytes. A requirement for NF-kappa B was established for KC self-induction. NF-kappa B inhibitors, p65 antisense oligonucleotides, or dominant-negative Ikappa Balpha inhibited this autocrine response. Mutation of a specific kappa B site in the KC promoter also blocked KC self-induction. Chromatin immunoprecipitation and in vivo footprinting confirmed the direct binding of NF-kappa B to the KC promoter. However, neither NF-kappa B nuclear translocation, increased Ikappa B degradation, nor upregulation of NF-kappa B DNA binding activity was observed after KC stimulation. Reporter gene assays demonstrated KC-upregulated NF-kappa B transcriptional activity, and this effect was inhibited by dominant-negative IkappaBalpha. Accumulation of NF-kappaB was noted within the nucleus in the presence of nuclear export inhibitor leptomycin B, demonstrating constitutive shuttling of NF-kappa B between the cytoplasm and nucleus. Blocking NF-kappa B shuttling inhibited KC transcription. KC induced p65 phosphorylation, which was critical for NF-kappa B activation as determined with the Gal-4-p65 fusion protein and mutation of p65 phosphorylation sites. In conclusion, low-level nuclear NF-kappa B is essential for KC self-induction, and this effect is mediated by shuttling and phosphorylation of NF-kappa B. The results outline a novel mechanism for NF-kappa B participation in transcription regulation.

Animals↗
PubMed2004

The stability of lyophilized lipid/DNA complexes during prolonged storage.

It is well known that excipients are required to protect nonviral vectors during the lyophilization process. The goal of this study is to describe the stability of lyophilized nonviral vector preparations on pharmaceutically relevant timescales and provide insight into the factors that govern long-term stability of vectors in the dried state. Lipid/DNA complexes were lyophilized in glucose, sucrose, or trehalose and stored for a period of up to 2 years at five different temperatures (-20, 4, 22, 40, 60 degrees C). We evaluated simultaneously the physico-chemical characteristics (size, zeta potential, ethidium bromide (EtBr) accessibility, supercoiled DNA content) and the ability of vector formulations to transfect COS-7 cells at different time intervals. In addition, a fluorescence assay was utilized to assess levels of ROS in the dried cake after storage. The physical state of each formulation was evaluated by determination of the glass transition temperature and residual moisture content, before and after storage. Results from our stability study show that a progressive degradation of lipid/DNA complexes occurs in terms of transfection rates, particle size, dye accessibility, and supercoil content, even when samples are stored at low temperatures (e.g., -20 degrees C). Furthermore, our preliminary results on the quantification of free radicals in rehydrated formulations emphasize the importance of developing strategies to prevent the formation of reactive oxygen species (ROS) during prolonged storage in the dried state.

Animals↗
PubMed2004

Mechanism for benzyl alcohol-induced aggregation of recombinant human interleukin-1 receptor antagonist in aqueous solution.

Benzyl alcohol, an antimicrobial preservative, accelerates aggregation and precipitation of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) in aqueous solution. The loss of native monomer during incubation at 37 degrees C was determined by analysis of sample aliquots with size exclusion high performance liquid chromatography (SE-HPLC). Benzyl alcohol caused minor perturbation of the tertiary structure of the protein without changing its secondary structure, documenting that the preservative caused a minor shift in the protein molecular population toward partially unfolded species. Consistent with this conclusion, in the presence of benzyl alcohol the rate of H-D exchange was accelerated and the fluorescence of 1-anilinonaphthalene-8-sulfonic acid in the presence of rhIL1ra was increased. Benzyl alcohol did not alter the free energy of unfolding based on unfolding experiments in urea or guanidine HCl. With differential scanning calorimetry it was determined that benzyl alcohol reduced the apparent Tm of rhIL-1ra, but this effect occurred because the preservative lowered the temperature at which the protein aggregated during heating. Isothermal calorimetry documented that the interaction of benzyl alcohol with rhIL-1ra is relatively weak and hydrophobically driven. Thus, benzyl alcohol accelerates protein aggregation by binding to the protein and favoring an increase in the level of partially unfolded, aggregation-competent species. Sucrose partially inhibited benzyl alcohol-induced aggregation and tertiary structural change. Sucrose is preferentially excluded from the surface of the protein, favoring most compact native state species over expanded aggregation-prone forms.

Benzyl Alcohol↗
PubMed2004

Remifentanil preconditioning protects against ischemic injury in the intact rat heart.

BACKGROUND: Opioid receptors mediate cardiac ischemic preconditioning. Remifentanil is a new, potent ultra-short-acting phenylpiperidine opioid used in high doses for anesthesia. The authors hypothesize that pretreatment with this drug confers cardioprotection. METHODS: Male Sprague-Dawley rats were anesthetized and the chest was opened. All animals were subjected to 30 min of occlusion of the left coronary artery and 2 h of reperfusion. Before the 30-min occlusion, rats received either preconditioning by ischemia (ischemic preconditioning, 5-min occlusion, 5-min reperfusion x 3) or pretreatment with remifentanil, performed with the same regime (3 x 5-min infusions) using 0.2, 0.6, 2, 6, or 20 microg.kg.min intravenously. The experiment was repeated with naltrindole (a selective Delta-opioid receptor antagonist, 5 mg/kg), norbinaltorphimine (a selective kappa-OR antagonist, 5 mg/kg), or CTOP (a selective mu-opioid receptor antagonist, 1 mg/kg) administered before remifentanil-induced preconditioning or ischemic preconditioning, respectively. Infarct size, as a percentage of the area at risk, was determined by 2,3,5-triphenyltetrazolium staining. RESULTS: There was a dose-related reduction in infarct size/area at risk after treatment with remifentanil that was similar to that seen with ischemic preconditioning. This effect was prevented or significantly attenuated by coadministration of a mu, kappa, or Delta-opioid antagonist. The infarct-sparing effect of ischemic preconditioning was abolished by blockade of kappa-opioid receptors or Delta-opioid receptors but not by mu-opioid receptors. CONCLUSION: Remifentanil mimics cardioprotection via all three opioid receptors. This differs from ischemic preconditioning, which confers cardioprotection via kappa- and Delta-, but not mu-opioid receptors. Part of the protective effect of remifentanil may be produced by mu-agonist activity outside the heart.

Animals↗
PubMed2004

[Effect of Jianwei Yuyang Granules on expression of epidermal growth factor receptor in gastric mucosa of gastric ulcer patients].

OBJECTIVE: To observe the effect of Jianwei Yuyang Granules on the expression of epidermal growth factor receptor (EGFR) in the gastric mucosa of gastric ulcer patients. METHODS: Sixty gastric ulcer patients (final diagnosis by gastroscope) were randomly divided into Jianwei Yuyang Granules treated group (JWYY group, n=30) and western medicine treated group (control group, n=30). Ten patients without gastric mucosa lesion were treated as normal control group. The expression of EGFR in the mucosa was tested by immunohistochemistry and RT-PCR. RESULTS: Expression of EGFR and EGFR mRNA was not observed in patients without gastric mucosa lesion, and slight expression was observed in the edge of ulcer region of the gastric ulcer patients. The expression of EGFR and EGFR mRNA was increased in JWYY group and control group. CONCLUSION: Jianwei Yuyang Granules enhances the expression of EGFR in the mucosa of gastric ulcer patients to prevent peptic ulcer recurrence.

Adult↗
PubMed2004

[Use of unfractionated heparin and a low-molecular-weight heparin following thrombolytic therapy for acute ST-segment elevation myocardial infarction].

OBJECTIVE: To compare the efficacy and safety of unfractionated heparin with a low-molecular-weight heparin (parnaparin) in the management of anticoagulation following thrombolytic therapy for acute ST-segment elevation myocardial infarction. METHODS: One hundred and eighty-six patients with acute ST-segment elevation myocardial infarction undergoing thrombolytic therapy were randomly assigned to receive either unfractionated heparin (100 U/kg x b.w. intravenous bolus, 1,000 U/h continuous infusion for 3 days just 12 h after thrombolysis to maintain the activated partial thromboplastin time at 1.5 to 2.0 times as normal, then subcutaneous 7500 U every 12 h for 4 days, n=90) or parnaparin (0.4 ml subcutaneously every 12 h for 7 days 12 h after thrombolysis, n=96) in conjunction with routine therapy. The patients enrolled stayed in hospital for at least 14 days and were followed for 45 days after admission into the hospital. RESULTS: The composite triple end-point (death, recurrent myocardial infarction, emergency revascularization assessed at 2, 7, 14, 45 days) was significantly reduced in patients receiving parnaparin 42.22% vs 37.08%, P=0.03 . Compared with unfractionated heparin group, the incidences of hemorrhage 10.00% vs 3.13%, P=0.06 and heparin-induced thrombocytopenia (3.33% vs 0, P=0.07) were also lower in parnaparin group. CONCLUSION: Parnaprin is more effective in reducing composite cardiac events, hemorrhage and heparin-induced thrombocytopenia at least in 45 days as compared with unfractionated heparin during anticoagulation following thrombolytic therapy for acute ST-segment elevation myocardial infarction.

Aged↗
PubMed2004

[Epidemiologic characteristics of influenza in China, from 2001 to 2003].

OBJECTIVE: To understand the epidemiologic characters of influenza in China from 2001 to 2003. METHODS: Data of outpatient visits for influenza-like illness (ILI) each week and outbreaks of influenza were collected through National Influenza Surveillance Network, which includes 11 northern and 12 southern provinces of China. Samples were collected in the outpatients of ILI from 2001 to 2003 and influenza viruses were isolated and identified. RESULTS: Epidemiological and laboratory surveillance data showed that the annual seasonality of influenza epidemic was clear. The peak of epidemic of influenza in northern areas was in winter season, during December to January. However, there were three peaks distributed to Spring (Apr.-May.), Summer (Jun.-Aug.) and Winter (Dec.-Jan.) seasons in the southern areas. In the peak months, the number of ILI visits per day and per surveillance hospital had increased two-fold in northern and by 37% in southern China. The baseline of percentages for ILI visits, which calculated with 75th percentiles (P75), was 13.68% in the north and 13.08% in southern China. The age distribution of ILI was related to seasonal types of influenza. When the predominated strain of the season was influenza B virus, the ratio of the ILI visits younger than 15 year-old, increased obviously. When the predominated stains became influenza A virus, the ratio of patient visits for ILI aged over 25 year-old increased. Of 63 outbreaks of influenza, 92% of them occurred at primary and middle schools and usually occurred in May (32%). The type of strains usually changed around June. CONCLUSION: The quality of national influenza surveillance system is reliable since it was matched between percentages of ILI visits and rates of influenza virus isolation. The different epidemiologic characteristics in north and south of China was noticed. Peak in spring was shown in southern area and which called for more analysis. The change of the types of strains in the outbreaks during April to June in the southern China could provide data for better understanding on the trend of epidemics in the next season.

Adolescent↗
PubMed2004

[Characterization of HA and NA genes of swine influenza A (H9N2) viruses].

OBJECTIVE: To understand the origin of HA and NA genes of swine influenza A (H9N2) viruses isolated from pigs in the mainland of China and on basis of these to reveal the pathogenicity of them in pigs. METHODS: The target gene was amplified by PCR, the PCR product was ligated with PGEM-T Easy Vector (Promega company, USA) at 4 degrees, the recombined plasmid was transferred into DH-10-beta bacteria; positive colonies were selected and identified then digested with restriction enzyme. Afterwards,the nucleotide sequence was determined. Finally,phylogenetic analysis of the sequencing data was performed with MegAlign (Version 1.03) and Editseg (Version 3.69) softwares. RESULTS: Two strains of swine influenza A(H9N2) virus isolated in the mainland had an amino acid residue, leucine (L) at position 226 (H3 numbering) on HA protein molecule found in H9N2 viruses isolated either in pigs or humans previously; the amino acid sequence at HA connecting peptide of isolates possessed R-L-S-R, whereas the other H9N2 viruses with virulence in poultry had R-S-S-R at HA connecting peptide. The two pig H9N2 isolates shared the same three-amino-acids deletion in the NA stalk at 62.64 position found in A/Shaoguan/408/98 and A/Swine/Hong Kong/9/98, as well as A/Duck/Hong Kong /Y280/97(H9N2) viruses. The analysis of the phylogenetic tree indicated that the HA and NA genes of new isolates were closely related to those of A/Chicken/Hong Kong/G23/97 and A/Chicken/Hong Kong/G9/97 and A/Shaoguan/408/98 viruses, respectively. CONCLUSION: The HA and NA genes of swine influenza A(H9N2) viruses isolated in the mainland of China probably were derived from those of avian influenza A(H9N2) virus. The occurrence of substitution of amino acid sequence at HA connecting peptide, could result in the H9N2 virus from non pathogenic to pathogenic in pigs. However, avian influenza A(H9N2) virus had deletion in the stalk of the NA that resulted in host range transmission. Therefore they could infect pigs directly.

Amino Acid Sequence↗
PubMed2004

[Antigenic and genetic characterizations of group A influenza viruses H3N2 circulated in men in China during 2000-2002].

OBJECTIVE: To understand the antigenic and genetic characteristics of influenza A H3N2 viruses circulated in man in China from 2000 to 2002. METHODS: Embryonated chicken eggs inoculated with virus for amplification of viral yield. The harvesting egg allantoic fluids with influenza viruses were provided for testing antigen and RNA extraction. Virion RNA was transcribed into cDNA by reverse transcriptase, cDNA amplified by PCR, and the product of PCR was purified. Afterward RNA sequence analysis was performed by the dideoxynucleotide chain termination method using synthetic oligodeoxynucleotide primers. Finally the phylogenetic tree was analyzed with MegAlign software. RESULTS: The H3N2 viruses isolated during 2000-2002 were different in amino acid sequences on HA1 domain protein molecule from those of A/Wuhan359/1995 H3N2 as well as those of A/Sydney/7/1997 H3N2 strains. There were four different positions of amino acid sequence on HA1 domain protein molecule among the H3N2 viruses isolated in 2000 and during 2001-2002. They located at 83, 186, 202, 222 and 225 position, respectively. Of them 83 and 186 were in antigenic determinant E and B, respectively. The others located at left wall of the receptor binding site (RBS). CONCLUSION: From the end of 2001 to the beginning of 2002, the influenza epidemic in Northern China caused by H3N2 virus was due to occurrence of antigenic and genetic changes of influenza A(H3N2) virus.

Amino Acid Sequence↗