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Biomedical subjects

Ying Xue

Publications and source records attributed to Ying Xue.

35 records · Page 2Linked to original sources
PubMed2005

[Immunity characteristics induced by a genetic vaccine expressing Ag85B-ESAT6 fusion protein].

OBJECTIVE: To evaluate the humoral and cell-mediated immune responses induced by a genetic vaccine expressing the Ag85B-ESAT6 fusion protein, and to investigate its protective effect against Mycobacterium tuberculosis (MTB) challenge. METHODS: Fifty BALB/c mice were randomized into 5 groups and subjected to the following treatments respectively: immunization with normal saline, BCG, pcDNA3, A(Z)-pcDNA3-E(F) and E(Z)-pcDNA3-A(F) for 3 times at 2-week intervals. The stimulation index (SI) of the splenic lymphocytes from the immunized mice was measured by the methyl thiazolyl tetrazolium (MTT) method, and the level of secreted IFN-gamma upon antigen-specific stimulation was detected by ELISA. The immunized mice were intravenously infected with 10(5) colony forming unit (CFU) of MTB H(37)Rv. The numbers of MTB CFU in spleens were determined 4 weeks later. RESULTS: The specific antibody titers in the sera of mice immunized with plasmid A(Z)-pcDNA3-E(F) and E(Z)-pcDNA3-A(F) were 1:1,000 and 1:1,500 respectively, and the SI was 2.2 and 2.4 respectively, while the SI of the normal saline group and the plasmid pcDNA3 immunized group was only 0.9 and 1.1 respectively. The IFN-gamma concentrations in cultured supernatant of splenic lymphocytes from mice immunized with plasmid A(Z)-pcDNA3-E(F) [(5.48 +/- 0.38) ng/ml] and E(Z)-pcDNA3-A(F) [(5.76 +/- 0.51) ng/ml] were significantly higher than those of the normal saline group [(0.50 +/- 0.25) ng/ml] and the plasmid pcDNA3 immunized group [(1.20 +/- 0.33) ng/ml, P < 0.05], but were not significantly different with that of the BCG immunized group [(5.55 +/- 0.31) ng/ml]. Compared with plasmid pcDNA3 immunized group, the bacterial load (lg, CFU/g) in spleen was 6.08 +/- 0.25 which dramatically reduced in mice immunized with recombinant plasmids, but the protective efficacy of mice immunized with plasmid A(Z)-pcDNA3-E(F) (4.63 +/- 0.11) or E(Z)-pcDNA3-A(F) (4.50 +/- 0.32) was lower than that of the BCG vaccination group (4.09 +/- 0.27). CONCLUSION: The cell-mediated immune response induced by genetic vaccine expressing the Ag85B-ESAT6 fusion protein was similar to that induced by BCG immunization.

Acyltransferases↗
PubMed2004

A theoretical study of solvent effects on tautomerism and electronic absorption spectra of 3-hydroxy-2-mercaptopyridine and 2,3-dihydroxypyridine.

The tautomerization equilibria of 3-hydroxy-2-mercaptopyridine (HMP) and 2,3-dihydroxypyridine (DHP) in vacuo and in ethanol solution have been studied using the density functional theory (DFT) at B3LYP/6-31Gd level. The results indicate that the thione form of HMP and the keto form of DHP are the most stable tautomers in the equilibrium, and the energy barrier for the thiol-thione and enol-keto proton transfer decreases significantly when the tautomerism is mediated by a specific ethanol molecule in solution. The time-dependent density functional theory--polarizable continuum model (TDDFT-PCM) calculations on all tautomers of HMP and DHP in vacuo and in ethanol have assigned the lowest pi --> pi* excitations of thione and keto tautomers to the observed absorption bands of HMP and DHP in solutions. The solvation is predicted to have relatively small effect on these pi --> pi* excitations in ethanol.

Journal Article↗
PubMed2004

Analysis of part of the Trichophyton rubrum ESTs.

Trichophyton rubrum (T. rubrum) is the most common of the superficial fungi. In an effort to better understand the genetic and biochemical makeup of T. rubrum, we generated cDNA libraries from 3 growth stages and used these to isolate 4002 unique expressed sequence tags (ESTs). Sequence comparisons with the Genbank database allowed 1226 of the ESTs to be assigned putative functions or matched with homologs from other organisms. Of the remaining ESTs, 989 were only weakly similar to known sequences and 1787 had no identifiable functions, suggesting that they represent novel genes. We further analyzed the presence of several important genes involved in the growth, metabolism, signal transduction, pathogenesis and drug resistance in T. rubrum. This information was used to newly elucidate important metabolic pathways in T. rubrum. Taken together, our results should form the molecular basis for continued research on the physiological processes and pathogenic mechanisms of T. rubrum, and may lead to a better understanding of fungal drug resistance and identification of new drug targets.

Computational Biology↗
PubMed2004

Development of hospice in China.

Hospice began in China with a research center founded in 1988. After a survey measured national attitudes about death, the ground was laid for the first clinical ward to be opened in October, 1990. The Chinese philosophy of hospice is consistent with the rest of the world--to provide holistic care to improve quality of life while keeping the family as the core unit of care.

China↗
PubMed2004

[Mycobacterium tuberculosis secreting protein Ag85B-ESAT6 fused expression and purification].

OBJECTIVE: To investigate the fused expression of secreted protein Ag85B-ESAT6 of Mycobacterium tuberculosis, and to provide a promising preventive subunit vaccine against tuberculosis. METHODS: The gene encoding Ag85B and ESAT6 protein was amplified by PCR from genome of Mycobacterium tuberculosis H(37)Rv strain, and inserted into cloning vector P(GEM)-T-easy. After sequence analysis, and digestion by restriction endonuclease, Ag85B-ESAT6 was cloned into corresponding sites of the expression vector P(PRO) EXHT, and the recombinant plasmid was transformed into expressive strain E. coli DH5 alpha, induced with IPTG and fusion protein was purified by Ni-NTA purification system. The specific antibody titer in the sera of BALB/c mouse immunized with two fusion protein was detected by ELISA. RESULTS: The sequences of Ag85B and ESAT6 by PCR amplification were identical to those reported by GenBank. The recombinant plasmid fused expression protein of Ag85B-ESAT6 with relative molecular mass (Mr) of 37,000, which was confirmed by Western-blot analysis with specific monoclonal antibody against 6 x HismAb. The fused expression protein was insoluble. It could be purified by Ni-NTA purification system. The specific antibody titer in the sera of BALB/c mouse immunized with fusion Ag85B-ESAT6 was 1:1000 and that of mouse immunized with fusion protein ESAT6-Ag85B was 1:5000. CONCLUSIONS: Secreted protein Ag85B-ESAT6 of Mycobacterium tuberculosis was successfully fused expressed in E. Coli DH5 alpha. It may become a new type of vaccine against tuberculosis.

Acyltransferases↗
PubMed2003

Ab initio studies for the photodissociation mechanism of hydroxyacetone.

The reaction pathways for CH(3)COCH(2)OH (hydroxyacetone) photodissociation on the low-lying electronic states have been studied with use of the CASSCF energy gradient techniques. The S(0)/S(1) and S(1)/T(1) intersection points were determined by the state-average CASSCF method. Two main reaction pathways, which are possible to the photodissociation, have been studied. It has been found that the mechanism is stepwise, and belongs to Norrish type-I reaction. The n --> pi* excitation leads to the first excited singlet state, followed by the intersystem crossing from S(1) to T(1). On the T(1) potential energy surface, the system can dissociate adiabatically to CH(3)(x) +COCH(2)OH( x) and CH(3)CO(x)+CH(2)OH(x). The COCH(2)OH(x) and CH(3)CO(x) radicals can further dissociate into CO, OH, and other fragments. Our calculated results are in good agreement with recent experimental results.

Journal Article↗
PubMed2003

Theoretical studies on the gas-phase pyrolysis of 2-phenoxycarboxylic acids: an ONIOM approach.

Various ONIOM combinations-ONIOM(HF/6-31G*: PM3), ONIOM(B3LYP/6-31G*: PM3), ONIOM(MP2/6-31G*: PM3), and ONIOM(MP2/6-31G*: HF/3-21G)--were applied to investigate thermal decomposition mechanisms of four 2-phenoxycarboxylic acids (2-phenoxyacetic acid, 2-phenoxypropionic acid, 2-phenoxybutyric acid, and 2-phenoxyisobutyric acid) in the gas phase. All the transition states and intermediates of the reaction paths were optimized. The reaction pathway of four reactants yielding the phenol, CO, and the corresponding carbonyl compound was characterized on the potential energy surface and found to proceed stepwise. The first step corresponds to the elimination of phenol and the formation of alpha-lactone intermediate through a five-membered ring transition state, and the second step is the cycloreversion process of alpha-lactone intermediate to form CO and the corresponding carbonyl compound. The reaction pathway of latter three compounds to produce the carboxylic acid and phenol via a four-membered cyclic transition structure was also examined theoretically. Comparison with experiment indicates that the activation parameters for the fist reaction channel are accurately predicted at the ONIOM(MP2/6-31G*: HF/3-21G) level of theory.

Journal Article↗
PubMed2003

[Analysis on Clenbuterol pollution in swine products in Beijing, 2002].

OBJECTIVE: To explore the status of clenbuterol pollution in swine products in Beijing city in 2002. METHODS: European Union method (EUR 15127-EN Cy2.3) was adopted to examine the samples. Samples were screened by enzyme-linked immunosorbent assay (ELISA) and confirmed by GC-MS. Detected limit of the method was 0.5 micro g/kg. Samples, including lung, liver, pork, kidney and urine of swine, were collected from slaughterhouses, refrigeratories and markets in 11 districts of Beijing. RESULTS: The results indicated that 185 out of 1 379 samples were positive with an annual positive rate of 13.4%. The highest was 15.7% in lung of swine, followed by urine 15.2% and pork liver 14.0%. CONCLUSION: Rates of detection had decreased from 30.0% to 2.7% during 2002.

Animals↗
PubMed2003

[Protective efficacy of DNA vaccines encoding mycobacterium tuberculosis Ag85B protein].

AIM: To explore protective efficacy of pTB30m and pTB30s encoding Ag85B protein against infection with M. tuberculosis H (37)R (v). METHODS: BALB/c mice were infected intravenously with 5x10(5) CFU of M. tuberculosisH (37)R (v) six weeks after the last vaccination of pTB30m and pTB30s. At the same time, normal BALB/c mice were injected intravenously with 5x10(6) T cells separated from immunized BALB/c mouse spleen through nylon wool column, and challenges were injected with 10(5) CFU of M. tuberculosis immediately intravenously. After 4 weeks, the CFU in spleens of infected mice were counted respectively. RESULTS: Vaccination with pTB30m and pTB30s produced significant protection against M. tuberculosis proliferation in the mouse spleens following challenge. As compared with the saline-injected mice, CFU in spleens of the mice vaccinated with pTB30m or pTB30s were reduced significantly, being 0.645(log(10) CFU, P<0.01) and 0.839(log(10) CFU, P<0.001), respectively. In contrast, bacterial load in the mice spleens vaccinated with empty plasmid only had little reduction. After adoptive immunization by T cells from the mice vaccinated with pTB30m and pTB30s, the mice might induce partial protection against M. tuberculosis proliferation in the mouse spleens following challenge. CONCLUSION: Protective efficacy of the mice immunized with pTB30s against challenge with M. tuberculosis virulent strain was better than that immunized with pTB30m.Thus, pTB30s is a promising DNA vaccine with respect to the prevention and treatment of tuberculosis.

Acyltransferases↗
PubMed2003

[Effects of Th1 cytokine gene on anti-CFP10 antibody production in BALB/c mice induced by Mycobacterium tuberculosis DNA vaccine].

AIM: To investigate the effects of plasmid containing mouse IL-12 and human IL-18 genes on the humoral immune response of mice immunized by CFP10 gene of Mycobacterium tuberculosis (MTB) H(37)R(v) strain. METHODS: Human IL-18 cDNA was amplified from RNA of PBMCs by RT-PCR and cloned into the pGEM-Teasy vector. After sequencing it was subcloned into the the sites of BamH I and EcoR I digestion of pcDNA3.1. BALB/c mice were injected intramuscularly by eukaryotic expression plasmid pcmIL12 and pcIL18, together with MTB CFP10 DNA vaccine, respectively. The same immunization repeated three times at intervals of two weeks. Mouse sera were collected at two weeks after the each injection. The titer of anti-CFP10 antibody was detected by ELISA. RESULTS: IL-18 cDNA was amplified successfully from RNA of human PBMCs by RT-PCR and the result of sequencing was correct. The IL-18 gene was correctly inserted into the vector pcDNA3.1 by being confirmed with BamH I and EcoR I digestion analysis, positive plasmid was called pcIL18. After being immunized with pcCFP10 three times, the end point titer of anti-CFP10 was 1:4 000, while the titer obtained by being immunized with pcIL18 + pcCFP10 was 1:8 000, but yet, after being immunized with pcmIL12+pcCFP10, the end point titer of anti-CFP10 antibody was only 1:200. CONCLUSION: Combination of IL-18 gene with MTB CFP10 DNA vaccine can enhance the humoral immune responses to pcCFP10, whereas the immunization with IL-12 gene plus pcCFP10 made humoral immune response markedly descent. As for whether IL-18 gene plus MTB CFP10 DNA vaccine can induce markedly the cellular mediated immune response to CFP10 or not remains to be further investigated.

Animals↗
PubMed2002

Genome sequence of Shigella flexneri 2a: insights into pathogenicity through comparison with genomes of Escherichia coli K12 and O157.

We have sequenced the genome of Shigella flexneri serotype 2a, the most prevalent species and serotype that causes bacillary dysentery or shigellosis in man. The whole genome is composed of a 4 607 203 bp chromosome and a 221 618 bp virulence plasmid, designated pCP301. While the plasmid shows minor divergence from that sequenced in serotype 5a, striking characteristics of the chromosome have been revealed. The S.flexneri chromosome has, astonishingly, 314 IS elements, more than 7-fold over those possessed by its close relatives, the non-pathogenic K12 strain and enterohemorrhagic O157:H7 strain of Escherichia coli. There are 13 translocations and inversions compared with the E.coli sequences, all involve a segment larger than 5 kb, and most are associated with deletions or acquired DNA sequences, of which several are likely to be bacteriophage-transmitted pathogenicity islands. Furthermore, S.flexneri, resembling another human-restricted enteric pathogen, Salmonella typhi, also has hundreds of pseudogenes compared with the E.coli strains. All of these could be subjected to investigations towards novel preventative and treatment strategies against shigellosis.

Amino Acid Sequence↗
PubMed2002

Density functional theory studies on the structures and vibrational spectra of 3,6-dichlorocarbazole and 3,6-dibromocarbazole.

Becke 3-Lee-Yang-Parr density functional theory (DFT) calculations using 6-311G** and 6-311G(2df,p) basis sets were carried out to study molecular structures and vibrational spectra of 3,6-dichlorocarbazole and 3,6-dibromocarbazole. The optimized geometries, vibrational frequencies, IR intensities, and Raman activities have been obtained. On the basis of B3LYP calculations, a normal mode analysis was performed to assign the vibrational fundamental frequencies according to the potential energy distributions. The computational frequencies are in good agreement with the observed results.

Bromine↗
PubMed2002

[Study on the anti-carcinogenic effects of three compounds in Kaempferia galanga L].

In order to study the anti-carcinogeneic effect of three compounds isolated from Kaempferia galanga L, EBV assay, ear edema test, ornithine decarboxylase (ODC) activity and two-stage-carcinogenisis test are applied. The results show that both -cis and -trans ethyl-p-methoxycinnamate has inhibitory effect in vitro, and also has inhibitory effects in TPA tests or croton oil-induced ear edema, ODC activity in specimen of mouse epidermis and extent of papilloma, indicating a relatively strong anti-carcinogenic potential of ethyl-p-methoxycinnamate in Kaempferia galanga L.

Animals↗
PubMedDate not supplied

Effect of selection of molecular descriptors on the prediction of blood-brain barrier penetrating and nonpenetrating agents by statistical learning methods.

The ability or inability of a drug to penetrate into the brain is a key consideration in drug design. Drugs for treating central nervous system (CNS) disorders need to be able to penetrate the blood-brain barrier (BBB). BBB nonpenetration is desirable for non-CNS-targeting drugs to minimize potential CNS-related side effects. Computational methods have been employed for the prediction of BBB-penetrating (BBB+) and -nonpenetrating (BBB-) agents at impressive accuracies of 75-92% and 60-80%, respectively. However, the majority of these studies give a substantially lower BBB- accuracy, and thus overall accuracy, than the BBB+ accuracy. This work examined whether proper selection of molecular descriptors can improve both the BBB- and the overall accuracies of statistical learning methods. The methods tested include logistic regression, linear discriminate analysis, k nearest neighbor, C4.5 decision tree, probabilistic neural network, and support vector machine. Molecular descriptors were selected by using a feature selection method, recursive feature elimination (RFE). Results by using 415 BBB+ and BBB- agents show that RFE substantially improves both the BBB- and the overall accuracy for all of the methods studied. This suggests that statistical learning methods combined with proper feature selection is potentially useful for facilitating a more balanced and improved prediction of BBB+ and BBB- agents.

Artificial Intelligence↗
PubMedDate not supplied

Unlicensed staff members' experiences with patients' pain on an inpatient oncology unit: implications for redesigning the care delivery system.

Although unlicensed staff have routine contact with patients in pain, little research relates to their role with these patients. The purpose of this study was to describe the experiences of unlicensed inpatient hospital staff caring for cancer patients in pain. We sought to understand pain identification and communication practices, describe common practice situations, and identify training needs. We conducted 4 focus groups with unit secretaries, nurses' aides, and housekeepers (N = 24) on 2 inpatient oncology units at an urban, northeastern teaching hospital. Group processes were tape-recorded, transcribed, and analyzed using Atlas/ti software and content analysis. Analysis generated 5 issues related to pain in the daily practice of unlicensed staff: perceived function with pain, building relationships with patients, interpreting patients' pain, system issues, and job challenges and coping strategies. Unlicensed staff reported performing important functions related to pain, including alerting nursing staff to patients' pain, and providing psychosocial support. Participants shared difficulties of working with patients in pain and expressed interest in education on pain identification and course of illness. Findings provide insight into the role of unlicensed staff, and have implications for the educational preparation of this group as well as the nature of their participation in the care delivery system.

Adaptation, Psychological↗