Biomedical subjects

Yi Jiang

Publications and source records attributed to Yi Jiang.

At least 37 records · Page 2Linked to original sources

PubMed2006

Massilia dura sp. nov., Massilia albidiflava sp. nov., Massilia plicata sp. nov. and Massilia lutea sp. nov., isolated from soils in China.

Four Gram-negative, motile, rod-shaped bacterial strains were isolated from soil samples collected from south-east China. A taxonomic study including phylogenetic analysis based on 16S rRNA gene sequences and phenotypic characteristics was performed. DNA G+C contents of the four strains were 63-66 mol%. Their predominant ubiquinone was Q-8. The fatty acid profiles contained C16:1omega7c (36.9-54.7%) and C16:0 (22.8-25.5%) as the major components. Based on their phenotypic characteristics, phylogenetic position as determined by 16S rRNA gene sequence analysis and DNA-DNA hybridization results, the four isolates are considered to represent four novel species of the genus Massilia, for which the names Massilia dura sp. nov. (type strain 16T=CCTCC AB 204070T=KCTC 12342T), Massilia albidiflava sp. nov. (type strain 45T=CCTCC AB 204071T=KCTC 12343T), Massilia plicata sp. nov. (type strain 76T=CCTCC AB 204072T=KCTC 12344T) and Massilia lutea sp. nov. (type strain 101T=CCTCC AB 204073T=KCTC 12345T) are proposed.

Base Composition↗

PubMed2006

Identification of essential host factors affecting tombusvirus RNA replication based on the yeast Tet promoters Hughes Collection.

To identify essential host genes affecting replication of Tomato bushy stunt virus (TBSV), a small model plant virus, we screened 800 yeast genes present in the yeast Tet promoters Hughes Collection. In total, we have identified 30 new host genes whose down-regulation either increased or decreased the accumulation of a TBSV replicon RNA. The identified essential yeast genes are involved in RNA transcription/metabolism, protein metabolism/transport, or other cellular processes. Detailed analysis of the effects of some of the identified yeast genes revealed that they might affect RNA replication by altering (i) the amounts/functions of p33 and p92(pol) viral replication proteins, (ii) the standard 10 to 20:1 ratio between p33 and p92(pol) in the viral replicase, (iii) the activity of the tombusvirus replicase, and (iv) the ratio of plus- versus minus-stranded RNA replication products. Altogether, this and previous genetic screening of yeast (Panavas et al., Proc. Natl. Acad. Sci. USA 102:7326-7331, 2005) led to the identification of 126 host genes (out of approximately 5,600 genes that represent approximately 95% of all the known and predicted yeast genes) that affected the accumulation of tombusvirus RNA.

Genes, Essential↗

PubMed2006

Screening of the yeast yTHC collection identifies essential host factors affecting tombusvirus RNA recombination.

RNA recombination is a major process in promoting rapid virus evolution in an infected host. A previous genome-wide screen with the yeast single-gene deletion library of 4,848 strains, representing approximately 80% of all genes of yeast, led to the identification of 11 host genes affecting RNA recombination in Tomato bushy stunt virus (TBSV), a small model plant virus (E. Serviene, N. Shapka, C. P. Cheng, T. Panavas, B. Phuangrat, J. Baker, and P. D. Nagy, Proc. Natl. Acad. Sci. USA 102:10545-10550, 2005). To further test the role of host genes in viral RNA recombination, in this paper, we extended the screening to 800 essential yeast genes present in the yeast Tet-promoters Hughes Collection (yTHC). In total, we identified 16 new host genes that either increased or decreased the ratio of TBSV recombinants to the nonrecombined TBSV RNA. The identified essential yeast genes are involved in RNA transcription/metabolism, in protein metabolism/transport, or unknown cellular processes. Detailed analysis of the effect of the identified yeast genes revealed that they might affect RNA recombination by altering (i) the ratio of the two viral replication proteins, (ii) the stability of the viral RNA, and/or (iii) the replicability of the recombinant RNAs. Overall, this and previous works firmly establish that a set of essential and nonessential host genes could affect TBSV recombination and evolution.

Base Sequence↗

PubMed2006

[Evaluation of association between an acute attack of childhood bronchial asthma and Chlamydia pneumoniae infection].

OBJECTIVE: To identify whether there is an association between an acute attack of childhood bronchial asthma and Chlamydia pneumoniae (CP) infection. METHODS: Serum specific antibodies IgM and IgG to CP were detected by ELISA in 120 asthmatic children with an acute attack and 82 healthy children. RESULTS: Anti-CP IgM was demonstrated in 22 cases (18.3%) and anti-CP IgG was demonstrated in 32 cases (26.7%) out of the 120 asthmatic patients. The incidence of CP infection in asthmatic children was significantly higher than that in healthy controls (3.7%) (P < 0.01). Glucocorticoid inhalation treatment alone resulted in a remission of an acute attack of asthma in 15 cases out of the 32 cases with CP infection, but 17 cases required glucocorticoid inhalation treatment together with anti-CP infection treatment (macrolide antibiotics, eg. azithromycin) for remission of asthma attack. CONCLUSIONS: There may be a link between an acute attack of childhood asthma and CP infection. It is thus necessary to detect the CP-specific antibodies in asthmatic children for proper treatment.

Acute Disease↗

PubMed2006

[Study on diversity of actinomycetes under salt and alkaline environments].

Actinomycetes have been attached a great attention owing to these microorganisms product various natural compounds and have special mechanism of adapting extreme environments. But the research work on actinomycetes under extreme environments is few. Soil and sediment samples were collected from saline and alkaline soil and lakes in Xinjiang, Qinghai Province, P. R. China and Egypt. Diversity and some biological characteristics of Actinomycete were studied by using cultivation and DGGE methods. Results showed that large amount of unknown microorganisms exist in the salt lake Chaka, isolated strains account for only a small portion of species diversity. Designing new strategies for isolation of as yet uncultured microorganisms from natural extreme environments is the key step to exploit microbial resources. The 87% of alkalophilic or alkalinetolerant actinomycete strains were able to grow at pH 6.0 - 12.0. 14 strains grow well at pH 8.5 - 11.5, but not at pH 7.0. 34 halotolerant actinomycete cab grow in 15% - 20% NaCl. Based on the study of the halophilic and halotolerant actinomycetes isolated from the saline and the alkaline soils collected from Xinjiang and Qinghai Province, China, we can conclude that the relationship of actinomycetes (especially halophilic actinomycetes strains) to positive ions such as Na+, K+ and Mg2+ is very complex, and there were sodiumphilic, kaliumphilic, magnesiumphilic, and calciumphilici actinomycete strains. One new family, eight new genera and more than 30 new species of halophilic and alkalophilic actinomycetes were fund. Many strains with PKS genes were selected. We believe based on the research results that there is a very high density of new or unknown actinomycete resources in these areas in China and Egypt.

Actinobacteria↗

PubMed2006

[Clinical evaluation of DLF, CLF and DFM regimens based on platinum compound plus 5-fluorouracil for treatment of advanced esophageal carcinoma].

BACKGROUND & OBJECTIVE: Combination chemotherapy with 5-fluorouracil (5-FU) and cisplatin is regarded as the standard regimen for advanced esophageal carcinoma. This study was to evaluate the efficacy and safety of DLF, CLF and DFM regimens, based on platinum compound plus 5-fluorouracil in the treatment of advanced esophageal carcinoma, and to further explore prognostic factors of advanced esophageal carcinoma. METHODS: From October 1999 to December 2004, 98 patients with advanced esophageal carcinoma were enrolled in the study. They were non-randomly assigned to receive a 2-hour infusion of folinic acid 200 mg/m(2), followed by a 5-FU bolus 400 mg/m(2) and 48-hour infusion of 5-FU 3,000 mg/m(2) every 3 weeks, combined with cisplatin 80 mg/m(2) (DLF, n=48) or with carboplatin AUC=5 on day 1 (CLF, n=32), or with cisplatin 80 mg/m(2), 5-fluorouracil bolus 400 mg/m(2) on day 1-5 plus pingyangmycin 5 mg/m(2) on day 1, 3, 5 (DFM, n=18). Survival analysis and prognostic factors were evaluated by Kaplan-Meier method and Cox regression analysis. RESULTS: All 98 patients were assessable for response and toxicity. There were 13 complete response, 36 partial response, 45 no changes and 4 progressive disease with a total response rate of 46.86%. The response rates of DLF, CLF and DFM regimens were 60.42%,46.86% and 27.78%, respectively (DLF vs DFM, P=0.027). The major side effects were nausea-vomiting, alopecia, bone marrow suppression and mucositis, and the others were uncommon. All side effects were tolerable and mild except for nausea-vomiting. Nausea-vomiting was mildest in CLF among the three regimens. After a median follow-up of 9 months, the overall median survival was 9 months (95% CI, 6.67 to 11.33 months), the median survival of the patients treated with DLF, CLF or DFM regimen was 10, 9 and 7 months, respectively (P=0.7402). Better prognosis was correlated with good conditions of patients before chemotherapy (KPS> or =80, P=0.000) and metastasis to lymph node, parenchyma or bone in stead of visceral organs (P=0.026). There was no correlation between the prognosis and age, sex, types of pathology and the regimen of therapy. CONCLUSIONS: The DLF regimen is tolerable and more effective, thus could be recommended as a front-line standard treatment for advanced esophageal carcinoma. The CLF regimen is more suitable for feeble and older patients since it has the mildest side effects. The prognostic factors of advanced esophageal carcinoma include conditions before chemotherapy and the location of metastasis.

Adenocarcinoma↗

PubMed2006

[Evaluation of early cognitive ability of infants born preterm by near-infrared spectroscopy].

OBJECTIVE: To compare the differences in cerebral oxygenation responses between the infants born preterm and full-term infants and to evaluate the early cognitive ability of infants born preterm. METHODS: Cerebral oxygenation after light stimulation was detected by near infrared spectroscopy (NIRS) in preterm infants at 3 or 6 months corrected gestational age (GA). The results were compared with those of age-matched infants born at term. RESULTS: The start and peak response time of cerebral oxygenation occurring after light stimulation in preterm infants at 3 months corrected GA was 17.2 +/- 5.2 and 38.4 +/- 9.6 seconds respectively, which were significantly longer than in age-matched term infants (13.1 +/- 2.7 and 28.9 +/- 5.0 seconds respectively) (P < 0.05). The maximum response value of hemoglobin, oxyhemoglobin and regional oxygen saturation of the preterm infants at 3 months corrected GA was (1.2 +/- 0.5)%, (1.5 +/- 0.6)%, and (1.3 +/- 0.4)% respectively , which were significantly lower than that of the term infants [(2.3 +/- 0.3)%, (2.8 +/- 0.3)% and (2.4 +/- 0.5)% respectively] (P < 0.05). Cerebral oxygenation responses to light stimulation in preterm infants examined at 6 months corrected GA were not significantly different from age-matched term infants. CONCLUSIONS: Cerebral oxygenation responses to light stimulation in infants born preterm at 3 months corrected GA are not as good as age-matched term infants, but were close to the level of age-matched term infants at 6 months corrected GA. This suggests that the early cognitive ability of preterm infants before 3 months corrected GA might fall behind age-matched term infants.

Brain↗

PubMed2006

[Study on the genotyping of 113 Mycobacterium tuberculosis strains isolated in Beijing based on 13 variable number of tandem DNA repeats].

OBJECTIVE: Variable Number of Tandem Repeats (VNTRs) analysis was a recently developed method which could serve as a 'real-time' genotyping tool for Mycobacterium tuberculosis. One hundred and thirteen M. tuberculosis isolates from the patients with tuberculosis in Beijing were analysed using the reference method to study the characters of genetic diversity and genotype. METHODS: Thirteen tandem repeat loci (ETR-A, ETR-C, ETR-D, MIRU10, MIRU16, MIRU27, MIRU31, MIRU40, Mtub21, Mtub30, Mtub38, Qublla, Qubllb) in the total genome of MTB were analyzed by PCR and agarose gel electrophoresis method. The characters of the polymorphism of DNA fingerprinting of one hundred and thirteen MTB strains were analyzed with Gel-Pro analyzer 3.1 software and BioNumerics 3.0 software. Results One hundred and thirteen MTB strains were characterized and classified in to four genotype families(type I , type II , type NV, type V ) based on thirteen tandem repeat loci. One hundred and four isolates(92.0%) belonged to type I , the other three genotypes scattered, five strains(4.4%) remaining with type II , while type IV and type V having the same quantity 1.8% (2/113). M. tuberculosis H37Rv belonged to a unattached genotype(type ll ). Conclusion There was obvious length polymorphism in the M. tuberculosis isolates which implied that type I was the epidemic strain clusters in M. tuberculosis in Beijing. VNTRs analysis seemed to be a simple, rapid, sensitive and valuable tool for epidemiological studies of M. tuberculosis complex organisms.

China↗

PubMed2005

The yeast prion protein Ure2: structure, function and folding.

The Saccharomyces cerevisiae protein Ure2 functions as a regulator of nitrogen metabolism and as a glutathione-dependent peroxidase. Ure2 also has the characteristics of a prion, in that it can undergo a heritable conformational change to an aggregated state; the prion form of Ure2 loses the regulatory function, but the enzymatic function appears to be maintained. A number of factors are found to affect the prion properties of Ure2, including mutation and expression levels of molecular chaperones, and the effect of these factors on structure and stability are being investigated. The relationship between structure, function and folding for the yeast prion Ure2 are discussed.

Amino Acid Sequence↗

PubMed2005

Nocardia lijiangensis sp. nov., a novel actinomycete strain isolated from soil in China.

A novel actinomycete strain YIM 33378T was isolated from a soil sample collected from Lijiang, Yunnan Province, China. Based on the results of phenotypic and genotypic characteristics, strain YIM 33378T should be assigned to a new species of the genus Nocardia, for which the name Nocardia lijiangensis sp. nov. is proposed. The type strain is YIM 33378T (= CCTCC AA 204005T = KCTC 19028T). The GenBank accession number for the sequence reported in this paper is AY779043.

Bacterial Typing Techniques↗

PubMed2005

Acryloylamino-salicylanilides as EGFR PTK inhibitors.

A series of acryloylamino-salicylanilides were synthesized as inhibitors of EGFR PTK. A strategy of pseudo six-membered ring formed through intramolecular hydrogen bonding in salicylanilides is employed to mimic the planar pyrimidine ring of quinazoline EGFR inhibitors. Acrylamido moiety is incorporated to target the Cys-773 of EGFR specifically. Some of the obtained compounds exhibited good activity as EGFR inhibitors.

Crystallography, X-Ray↗

PubMed2005

Polymorphism of the mouse gene for the interleukin 10 receptor alpha chain (Il10ra) and its association with the autoimmune phenotype.

Several studies suggest that interleukin (IL)-10 pathway is involved in murine lupus, while no linkage of IL-10 gene polymorphism to disease susceptibility has been reported in studies with lupus-prone mice. Since IL-10 functions through the specific IL-10 receptor alpha (IL-10RA) chain and the IL-10RA gene (Il10ra) is linked to the susceptibility loci of atopic dermatitis and Crohn's disease identified using mouse models, we supposed that IL-10RA might be involved in murine lupus. By flow cytometry analysis, we found that NZW mice, one of the parental strains of lupus-prone (NZBxNZW) F1 mice, express extremely low levels of IL-10RA compared with NZB mice, the other parental strain, and the healthy BALB/c and C57BL/6 mice. Sequence analyses of Il10ra cDNA of NZW mice showed multiple nucleotide mutations compared with that of NZB and C57BL/6 strains, some of which would result in amino acid substitutions in the IL-10RA protein. Lupus-prone MRL mice shared the same polymorphism with NZW. Analyses using (NZBxNZW) F1xNZB backcross mice showed that high serum levels of IgG antichromatin antibodies were regulated by a combinatorial effect of the NZW Il10ra allele and a heterozygous genotype for Tnfa microsatellite locus. Our data suggest that the polymorphic NZW-type Il10ra may be involved in the pathologic production of antichromatin antibodies and, if so, may contribute in part to the development of systemic lupus erythematosus as one susceptibility allele.

Animals↗

PubMed2005

Expressions of inducible nitric oxide synthase and matrix metalloproteinase-9 and their effects on angiogenesis and progression of hepatocellular carcinoma.

AIM: To determine the expressions of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-9 (MMP-9) in hepatocellular carcinoma (HCC) and to investigate the relationship between iNOS and MMP-9 expression and their effects on angiogenesis and progression of HCC. METHODS: In this study, we examined iNOS, MMP-9, and CD34 expression in specimens surgically removed from 32 HCC patients and 7 normal liver tissues by immunohistochemical staining. Meanwhile, microvessel density (MVD) was determined as a marker of angiogenesis by counting CD34-positive cells. RESULTS: The positive rates of iNOS and MMP-9 expression were 71.88% (23/32) and 78.13% (25/32) in HCC. MMP-9 expression was significantly correlated with tumor size, capsule status, TNM stage, and risk of HCC recurrence (P = 0.032, P = 0.033, P = 0.007, and P = 0.001, respectively). There was also a significant relationship between iNOS expression and capsule status and risk of HCC recurrence (P = 0.049 and P = 0.004, respectively), but no correlation between iNOS expression and tumor size and TNM stage. There was a positive association between MVD and TNM stage and risk of HCC recurrence (P = 0.037 and P = 0.000, respectively). The count of MVD was significantly different in different iNOS and MMP-9 immunoreactivity groups (F = 17.713 and 17.097, P = 0.000 and P = 0.000, respectively). The examination of Spearman's rank correlation coefficient showed that there was a significant positive correlation between MVD and iNOS, MMP-9 immunoreactivity (r = 0.754 and 0.751, P = 0.000 and P=0.000, respectively). There was also a significant association between MMP-9 and iNOS expression in HCC (P = 0.010). CONCLUSION: Nitric oxide (NO) produced by iNOS could modulate MMP-9 production and therefore contribute to tumor cell angiogenesis and invasion and metastasis in HCC. The strong expression of iNOS and MMP-9 in HCC may be helpful in evaluating the recurrence of HCC, predicting poor prognosis. For patients with strong expression of MMP-9 and iNOS, the optimal treatment scheme needs to be selected.

Adolescent↗

PubMed2005

A multiscale model for avascular tumor growth.

The desire to understand tumor complexity has given rise to mathematical models to describe the tumor microenvironment. We present a new mathematical model for avascular tumor growth and development that spans three distinct scales. At the cellular level, a lattice Monte Carlo model describes cellular dynamics (proliferation, adhesion, and viability). At the subcellular level, a Boolean network regulates the expression of proteins that control the cell cycle. At the extracellular level, reaction-diffusion equations describe the chemical dynamics (nutrient, waste, growth promoter, and inhibitor concentrations). Data from experiments with multicellular spheroids were used to determine the parameters of the simulations. Starting with a single tumor cell, this model produces an avascular tumor that quantitatively mimics experimental measurements in multicellular spheroids. Based on the simulations, we predict: 1), the microenvironmental conditions required for tumor cell survival; and 2), growth promoters and inhibitors have diffusion coefficients in the range between 10(-6) and 10(-7) cm2/h, corresponding to molecules of size 80-90 kDa. Using the same parameters, the model also accurately predicts spheroid growth curves under different external nutrient supply conditions.

Animals↗

PubMed2005

Sonolysis of 4-chlorophenol in aqueous solution: effects of substrate concentration, aqueous temperature and ultrasonic frequency.

The sonolysis of 4-chlorophenol (4-CP) in O2-saturated aqueous solutions is investigated for a variety of operating conditions with the loss of 4-CP from solution following pseudo-first-order reaction kinetics. Hydroquinone (HQ) and 4-chlorocatechol (4-CC) are the predominant intermediates which are degraded on extended ultrasonic irradiation. The final products are identified as Cl-, CO2, CO, and HCO2H. The rate of 4-CP degradation is dependent on the initial 4-CP concentration with an essentially linear increase in degradation rate at low initial 4-CP concentrations but with a plateauing in the rate increase observed at high reactant concentrations. The results obtained indicate that degradation takes place in the solution bulk at low reactant concentrations while at higher concentrations degradation occurs predominantly at the gas bubble-liquid interface. The aqueous temperature has a significant effect on the reaction rate. At low frequency (20 kHz) a lower liquid temperature favours the sonochemical degradation of 4-CP while at high frequency (500 kHz) the rate of 4-CP degradation is minimally perturbed with a slight optimum at around 40 degrees C. The rate of 4-CP degradation is frequency dependent with maximum rate of degradation occurring (of the frequencies studied) at 200 kHz.

Journal Article↗

PubMed2005

A three-dimensional model of myxobacterial aggregation by contact-mediated interactions.

Myxobacteria provide one of the simplest models of cell-cell interaction and organized cell movement leading to cellular differentiation. When starved, tens of thousands of cells change their movement pattern from outward spreading to inward concentration; they form aggregates that become fruiting bodies. Cells inside fruiting bodies differentiate into round, nonmotile, environmentally resistant spores. Traditionally, cell aggregation has been considered to imply chemotaxis; a long-range cell interaction. However, myxobacterial aggregation is the consequence of direct cell-contact interactions, not chemotaxis. We present here a 3D stochastic lattice-gas cellular automata model of cell aggregation based on local cell-cell contact, and no chemotaxis. We demonstrate that a 3D discrete stochastic model can simulate two stages of cell aggregation. First, a "traffic jam" forms embedded in a field of motile cells. The jam then becomes an aggregation center that accumulates more cells. We show that, at high cell density, cells stream around the traffic jam, generating a 3D hemispherical mound. Later, when the nuclear traffic jam dissolves, the aggregation center becomes a 3D ring of streaming cells.

Models, Biological↗

PubMed2005

Metavanadate suppresses desferrioxamine-induced leukemic cell differentiation with reduced hypoxia-inducible factor-1alpha protein.

We recently showed that moderate hypoxia and hypoxia-mimetic agents CoCl(2) and desferrioxamine (DFO) induce differentiation of acute myeloid leukemic cells via hypoxia-inducible factor-1alpha (HIF-1alpha) that interacts with and increases the transcriptional activity of CCAAT/enhancer-binding protein alpha (C/EBPalpha), a critical factor for granulocytic differentiation. Here, we show that metavanadate antagonizes DFO-induced growth arrest and differentiation with the inhibition of HIF-1alpha protein accumulation in leukemic cells. Furthermore, DFO also increased C/EBPalpha expression rapidly but transiently, which was inhibited by metavanadate. Taken together, these findings provide further evidence for the role of HIF-1alpha and C/EBPalpha in DFO-induced leukemic cell differentiation.

Animals↗

PubMed2005

Aflatoxin B1 albumin adduct levels and cellular immune status in Ghanaians.

Although aflatoxins (AFs) have been shown to be immune-suppressive agents in animals, the potential role of AFs in modifying the distribution and function of leukocyte subsets in humans has never been assessed. We examined the cellular immune status of 64 Ghanaians in relation to levels of aflatoxin B1 (AFB1)-albumin adducts in plasma. The percentages of leukocyte immunophenotypes in peripheral blood, CD4+ T cell proliferative response, CD4+ T(h) and CD8+ T cell cytokine profiles and monocyte phagocytic activity were measured using flow cytometry. NK cell cytotoxic function was determined by perforin and tumor necrosis factor-alpha expression in CD3-CD56+ NK cells. AFB1-albumin adducts levels ranged from 0.3325 to 2.2703 (mean = 0.9972 +/- 0.40, median = 0.9068) pmol mg(-1) albumin. Study participants with high AFB1 levels had significantly lower percentages of CD3+ and CD19+ cells that showed the CD69+ activation marker (CD3+CD69+ and CD19+CD69+) than participants with low AFB1 levels (P = 0.002 for both). Also, the percentages of CD8+ T cells that contained perforin or both perforin and granzyme A were significantly lower in participants with high AFB1 levels compared with those with low AFB1 (P = 0.012 for both). Low levels of CD3+CD69+ (r = -0.32, P = 0.016) and CD19+CD69+ (r = -0.334, P = 0.010) cells were significantly associated with high AFB1 levels using correlation analysis. By multivariate analysis, there were strong negative correlations between the percentages of these cells (CD3+CD69+: b = -0.574, P = 0.001, and CD19+CD69+: b = -0.330, P = 0.032) and AFB1 levels. These alterations in immunological parameters in participants with high AFB1 levels could result in impairments in cellular immunity that could decrease host resistance to infections.

Adult↗