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Biomedical subjects

Xin Jiang

Publications and source records attributed to Xin Jiang.

At least 37 records · Page 2Linked to original sources
PubMed2006

Comparison of the proteome of isoniazid-resistant and -susceptible strains of Mycobacterium tuberculosis.

In an effort to determine whether there is a major difference in protein level between isoniazid resistant and susceptible Mycobacterium tuberculosis strains, the proteins extracted from nine isoniazid (INH) monoresistant M. tuberculosis strains, seven isoniazid susceptible M. tuberculosis strains, and M. tuberculosis H37Rv, were analyzed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In all protein spot differences, five protein spots that are upregulated in INH-resistant strains were identified as Rv1446c, Rv3028c, Rv0491, Rv2971, and Rv2145 by matrix-assisted laser desorption/ionization-time of fight-mass spectrometry (MALDI-TOF-MS). Most of these differential proteins are membrane proteins, which are known to be rich in potential diagnostic and therapeutic protein targets. These results suggest that the differentially expressed proteins from INH-resistant strains might be used as potential immunodiagnosis antigens and candidate novel drug targets against drug-resistant tuberculosis.

Genome, Bacterial↗
PubMed2006

[Analysis of shape and retractability of the prepuce in 1,015 Chinese boys aged from 0 to 18 years old].

OBJECTIVE: To evaluate the characteristics of the preputial development in Chinese boys and indications as well as occasion of circumcision. METHODS: The shape and retractability of prepuce were evaluated in 1,015 Chinese boys from 0 to 18 years old without heteroplasia of prepuce and penis. RESULTS: Ratio of children with phimosis decreases progressively with increasing age, from 64.09% in the first group (0 approximately 3 years old) to 7.66% in the fourth group (11 approximately 18 years old). CONCLUSION: Phimosis and incomplete separation of the prepuce is normal in the neonate and infant. Prepuce will separate from the glans progressively till adolescence, so it's unnecessary to perform circumcision for them when without any complications.

Adolescent↗
PubMed2006

[Effect of chlorpyrifos residue in red soil on crops].

The pot cultivation experiment method, integrating with laboratory analysis, was employed for exploring the influence of chlorpyrifos residue in red soil on growth of wheat and oil-seed rape seedlings, and the uptake of crops to chlorpyrifos residue. The results show that, wheat seedlings and oil-seed rape seedlings can absorb chlorpyrifos residue from soil to reach the concentration of 0.257 to approximately 4.50 microg/g and 0.249 to approximately 2.021 microg/g, respectively, 20 days later since chlorpyrifos was introduced into the pots, on condition that the initial concentration of chlorpyrifos residue in red soil was 1 to approximately 10 microg/g. The initial concentration of chlorpyrifos residue in red soil equivalent to or below 10 micro/g has not significant influence on growth of wheat seedlings. Similarly, the concentration equivalent to or below 5 microg/g has not significant influence on growth of oil-seed rape seedlings. The degradation rate in oil-seed rape rhizosphere soil is 1.4 to approximately 4.2 times more than in that in unvegetated soil. The amount of bacterium and fungus in oil-seed rape rhizosphere is 3.18 times and 1.84 times as much as these in unvegetated soil, respectively. However, there is no substantial difference of actinomyces between in rhizosphere soil and in unvegetated soil. Compared with unvegetated soil, pH in rhizosphere soil is lowered by 0. 19 to approximately 0.23.

Chlorpyrifos↗
PubMed2006

[The effects of 40 mg atorvastatin on serum lipids, inflammatory markers and clinical events in ACS patients post PCI].

OBJECTIVE: To assess the safety and effects of 40 mg atorvastatin on serum lipids, inflammatory markers and clinical events in ACS patients post PCI. METHODS: A total of 92 patients with ACS post successful PCI were randomly divided into atorvastatin 10 mg/d (group A) and atorvastatin 40 mg/d (group B) on top of the standard medical therapy. Blood were taken at baseline, 4, 12 and 24 weeks for serum alanine aminotransferase (ALT), lipids, high-sensitive C-reactive protein (hs-CRP) and matrix metalloprotease-9 (MMP-9) measurements. The major adverse cardiac events (MACE) were also observed. RESULTS: There was no significant difference in medication withdrawn (2 vs. 3 cases) due to increased ALT (3 times higher than normal) and incidence of MACE (5 vs. 7 cases) between the groups. TC and LDL were significantly reduced in both groups 4 weeks and thereafter post medication compared to pre-treatment (P < 0.05) and the reduction was more significant in group B than that in group A at 24 weeks post medication (P < 0.05) while TG and HDL remained unchanged. hs-CRP was significantly reduced at 12 and 24 weeks in both groups compared to baseline and the reduction was more significant in group B than that in group A at 24 weeks. MMP-9 was significantly reduced in both groups 4 weeks and thereafter post medication compared to pre-treatment (P < 0.05) and the reduction was more significant in group B than that in group A at 12 weeks post medication (P < 0.05). CONCLUSION: Both atorvastatin doses significantly reduced TC, LDL, hs-CRP and MMP-9 in ACS patients post PCI and the reduction was more significant in high dose atorvastatin group at 24 weeks while the MACE and drug withdraw rates were similar between the groups.

Acute Coronary Syndrome↗
PubMed2006

[Contribution of endothelin and its receptors to ouabain-induced hypertension in rats].

OBJECTIVE: To investigate the effect of endothelin and its receptors on ouabain-induced hypertension in rats. METHODS: Male Sprague-Dawley (SD) rats were treated with ouabain or saline for 6 weeks and their systolic blood pressure (SBP) were recorded weekly. At the end of 2, 4 and 6 weeks, respectively, the plasma and left ventricle endothelin contents were measured by radio-immunoassay, and real-time quantitative RT-PCR was employed to determine the mRNA level of endothelin type A receptor (ETAR) and type B receptor (ETBR) in the left ventricle, and the protein expressions of ETAR and ETBR were examined by immuno-histochemistry. RESULTS: After 4 weeks of intraperitoneal ouabain injection, the mean SBP in ouabain group increased till reaching a level significantly higher than that in the control group after 6 weeks (P<0.001). The plasma and left ventricle endothelin contents were significantly increased after 2 weeks of ouabain injection (P<0.01), and similarly, increased ETAR mRNA was observed. After 4 weeks of treatment, ETAR mRNA was increased continuously and the protein expression of ETAR upregulated in ouabain group as compared with the control group. The transcription and protein expression of ETBR were not altered by ouabain treatment. CONCLUSION: Before detectable blood pressure elevation occurs, endothelin concentration and ETAR can be already upregulated in ouabain-induced hypertensive rats, suggesting that endothelin might be involved in the cardiovascular effects of ouabain via an action on ETAR.

Animals↗
PubMed2006

[Effect of ouabain on cardiac function and myocardium ultrastructure of rat].

OBJECTIVE: To investigate the changes in rat cardiac function and myocardium ultrastructure in response to ouabain treatment. METHODS: Twenty-four male SD rats were randomized into two equal groups to receive daily intraperitoneal injection of ouabain or saline for 4 consecutive weeks, and their systolic blood pressure (SBP) was recorded weekly. After 4 weeks of injection, echocardiography was performed and the hemodynamic parameters were measured by invasive cardiac catheterization, and the changes in myocardium ultrastructure observed using transmission electron microscopy. RESULTS: After 4 weeks of ouabain injection, no significant changes in the mean SBP occurred in comparison with the saline group, but echocardiographic examination showed significant increases in the left ventricular end-diastolic and end-systolic diameters, septum thickness, posterior wall thickness, left ventricular mass and isovolumetric relaxation time but significantly lowered E/A ratio, ejection fraction and fractional shortening after ouabain treatment (P<0.05). Invasive monitoring revealed significant attenuation of the left ventricular developed pressure, rate of pressure development (+dp/dt) and rate of pressure decay (-dp/dt), and increment of the left ventricular end diastolic pressure. Myofibrillar fragmentation, swelling of the cardiac myocytes, absence of the Z line, increases of the mitochondria and collagen fibers were found in ouabain group by transmission electron microscopy. CONCLUSION: Ouabain can induce left ventricular enlargement, cardiac wall thickening, myocardial ultrastructural alterations, systolic and diastolic dysfunction in rats before blood pressure elevation is detected, indicating that ouabain can directly cause cardiac damage in rats.

Animals↗
PubMed2006

[Effects of several low-molecular-weight organic acids on the release kinetic of DDTs from red soil].

The kinetic release behavior of DDTs from red soil with three kinds of low-molecular-weight (LMW) organic acids solution and water leaching was investigated by kinetic device designed. The results show that the release percentage of DDTs from red soil by LMW organic acid can increase by 15% - 18% more than that by water, especially for the initial 250 mL leaching solution. When using water as leaching solution, the data of release kinetics of DDTs from red soil conformed to the apparently first dynamics equation (R2 > 0.99, p < 0.000 1), it implied that the surface diffuse of soil mineral is primary release mechanism of DDTs from red soil in water leaching system. The kinetic release behavior of DDTs in LMW organic acid leaching system can be described by parabola diffuse equation, double constant equation or Elovich equation. It implied that the LMW organic acids induced the complication of the release mechanisms of DDTs from red soil, this maybe related to the dissolution of soil mineral surface and structure change of inherent organic material that coating onto the soil mineral surface induced by LMW organic acid.

Acids↗
PubMed2006

[Meta-analysis of association of deletion allele of angiotensin-converting enzyme gene with coronary heart disease in China].

OBJECTIVE: To qualitatively and quantitatively assess the evidence regarding the relation of ACE I/D polymorphism to coronary heart disease (CHD) risk. METHODS: Medline (January 1994 to February 2005) and China Hospital Knowledge Databases (January 1994 to May 2005) were retrieved for all publications relating to case-control studies reporting a link between CHD risk factors and the ACE I/D polymorphism. All 16 association studies were identified and a meta-analysis was conducted by using the RevMan 4.2 estimate for odds ratio (OR) to determine whether the DD genotype might predict the outcome in CHD. RESULTS: Sixteen out of 48 identified studies reporting data on 1345 CHD patients and 1286 matched controls fulfilled these inclusion criteria. The overall distribution of genotypes in the control subjects was 35.88% II, 40.86% ID, and 23.26% DD. The odds ratio for CHD for DD versus ID/II genotypes across all studies was 2.56 [95% CI, 2.09 - 3.13]. The relative CHD risk appeared to be increased with the D allele (chi(Trend)(2) = 97.12, P < 0.01). CONCLUSIONS: ACE gene I/D polymorphism should be associated with susceptivity of coronary heart disease in China. The CHD risk is increased significantly in individuals with DD genotypes. The ACE D allele should be a risk factor for CHD.

Alleles↗
PubMed2006

[Expression and purification of Rv3369 of Mycobacterium tuberculosis].

To obtain purified recombinant Rv3369 protein by means of expressing the Rv3369 protein of Mycobacterium tuberculosis in E. coli. The gene coding Rv3369 protein was amplified by polymerase chain reaction (PCR), then was inserted into an expression vector pET28a to get recombinant plasmid. The recombinant plasmid was transformed into E. coli BL21(DE3) and induced by IPTG. The expressed product was indentified by SDS-PAGE and purified by Ni- NTA His. Bind Resin. The sequence of Rv3369 in recombinant plasmid was the same with GenBank's report. The molecular mass of the product is 19.5kDa, which accounts for about 20% in the thalli proteins, and its purity is more than 90% analyzed by SDS-PAGE and laser scanning. The yield of recombinant protein is 1.56mg from 100mL of culture. Compared with other methods, purity of the recombinant protein is higher through affinity chromatography.

Bacterial Proteins↗
PubMed2005

Rv2131c gene product: an unconventional enzyme that is both inositol monophosphatase and fructose-1,6-bisphosphatase.

Inositol monophosphatase is an enzyme in the biosynthesis of myo-inostiol, a crucial substrate for the synthesis of phosphatidylinositol, which has been demonstrated to be an essential component of mycobacteria. In this study, the Rv2131c gene from Mycobacterium tuberculosis H37Rv was cloned into the pET28a vector and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) strain, allowing the expression of the enzyme in fusion with a histidine-rich peptide on the N-terminal. The fusion protein was purified from the soluble fraction of the lysed cells under native conditions by immobilized metal affinity chromatography (IMAC). The purified Rv2131c gene product showed inositol monophosphatase activity but with substrate specificity that was broader than those of several bacterial and eukaryotic inositol monophosphatases, and it also acted as fructose-1,6-bisphosphatase. The dimeric enzyme exhibited dual activities of IMPase and FBPase, with K(m) of 0.22+/-0.03mM for inositol-1-phosphate and K(m) of 0.45+/-0.05mM for fructose-1,6-bisphosphatase. To better understand the relationship between the function and structure of the Rv2131c enzyme, we constructed D40N, L71A, and D94N mutants and purified these corresponding proteins. Mutations of D40N and D94N caused the proteins to almost completely lose both the inositol monophosphatase and fructose-1,6-bisphosphatase activities. However, L71A mutant did not cause loss either of the activities, but the activity toward the inositol was 12-fold more resistant to inhibition by lithium (IC(50) approximately 60mM). Based on the substrate specificity and presence of conserved sequence motifs of the M. tuberculosis Rv2131c, we proposed that the enzyme belonged to class IV fructose-1,6-bisphosphatase (FBPase IV).

Amino Acid Sequence↗
PubMed2005

Low-temperature synthesis of amorphous carbon nanocoils via acetylene coupling on copper nanocrystal surfaces at 468 K: a reaction mechanism analysis.

A new type of amorphous helical carbon nanofibers has been synthesized using copper nanocatalysts and an acetylene gas source at atmospheric pressure. The nanofibers are grown at 468 K, which is the lowest temperature by ordinary metal-catalyzed thermal chemical vapor deposition of hydrocarbon, and exhibit a symmetric growth mode in the form of twin helices. IR, XRD, Raman, and C/H molar ratio analyses reveal a polymer-like structure with a weak trans-polyacetylene feature. The nanofibers are a mixture of solid polymers and a small amount of carbon. A reaction mechanism has been proposed on the basis of the previous studies of acetylene adsorption, desorption properties, and surface reactions on copper (111), (110), and (001) planes under ultrahigh-vacuum (UHV) conditions as well as the results obtained in our study. The reaction mechanism of acetylene on copper single-crystal surfaces under UHV conditions indeed reflects the reaction mechanism under practical catalytic conditions at atmospheric pressure. The nanofibers grow mainly via acetylene coupling to solid polymers on copper nanocrystal surfaces. Acetylene also couples to yield small amounts of liquid oligomers and gaseous products, and undergoes slight carbon deposition during the fiber growth.

Acetylene↗
PubMed2005

Quantitative structure-toxicity relationships of organophosphorous pesticides to fish (Cyprinus carpio).

This study was conducted to determine the relationships between 1381 chemical and structural parameters of 43 organophosphorus pesticides (OPs) and their toxicity to fish, Cyprinus carpio, using ChemOffice 8.03 and Dragon 2.1. By multivariate linear regression and intervariable regression analyses, various equations have been derived to calculate the lethal toxicity value, LC(50), for 43 OPs found in fish with different levels of toxicity. Results show that for all selected OPs, especially those of low toxic OPs (LC(50)< 2.5 mM), the equation, LC(50) = 56.259 - 13.071 lg K(ow)+17.510 MATS8P-17.455 Mor24u - 0.085 MW + 1.706 (lg K(ow))(2) + 2.306 (Mor14e)(2) + 6.849 Mor20 m (n = 43, F = 36.815, r = 0.942, r(adj)(2) = 0.862, SE = 2.899, p < 10(-6)), could account for 86.2% of the variability of the toxic effect. The steric and electronic characteristics and the hydrophobicity of OPs, in particular, are among the most important parameters determining the toxicity of OPs to fish. For the OPs with high toxicity, different structural parameters were introduced into the following two equations: LC(50)=3.795-1.195 (H1p)(2)-0.037 U-2.225 MATS3v-19.593 Tcon (n = 16, F = 56.820, r = 0.977, r(adj)(2) = 0.937, SE = 0.143, p < 10(-6)), where LC(50) is less than 2.5 mM, and LC(50) = 0.341-0.561 (HOMA)(2) + 0.231 HOMA (n = 3,r(adj)(2) = 1), where LC(50) is less than 0.3 mM. These results suggest that chemical and structural parameters could be useful in modeling chemical reactivity within homologous series of OP compounds and elucidating possible mechanisms associated with different levels of toxicity to fish.

Animals↗
PubMed2005

Synthesis and complete stereochemical assignment of psymberin/irciniastatin A.

We describe a concise and flexible synthetic avenue for the preparation of compounds with structures relevant to those proposed for the novel marine-derived differential cytotoxins psymberin and irciniastatin A. Our efforts led to their complete stereochemical assignment and the notion that psymberin and irciniastatin A are identical compounds. Our total synthesis features an interesting termini-differentiating lactolization of a dialdehyde obtained from a C2-symmetrical bis-olefin precursor, a mild platinum-catalyzed hydrolysis of an epimerizable nitrile, a novel protocol to prepare sensitive methyl imidates, and a one-pot conversion of these imidates to N-acyl aminals. Starting from fragments 5-7 (prepared in 7-8 steps each, 30-49% overall yield) the synthesis of psymberin/irciniastatin A was completed in an additional 9 steps and 30% yield (17 steps longest linear sequence, 8.9% overall).

Coumarins↗
PubMed2005

Potent and selective structure-based dibenzofuran inhibitors of transthyretin amyloidogenesis: kinetic stabilization of the native state.

Transthyretin (TTR) amyloidogenesis requires rate-limiting tetramer dissociation and partial monomer denaturation to produce a misassembly competent species. This process has been followed by turbidity to identify transthyretin amyloidogenesis inhibitors including dibenzofuran-4,6-dicarboxylic acid (1). An X-ray cocrystal structure of TTR.1(2) reveals that it only utilizes the outer portion of the two thyroxine binding pockets to bind to and inhibit TTR amyloidogenesis. Herein, structure-based design was employed to append aryl substituents at C1 of the dibenzofuran ring to complement the unused inner portion of the thyroxine binding pockets. Twenty-eight amyloidogenesis inhibitors of increased potency and dramatically increased plasma TTR binding selectivity resulted. These function by imposing kinetic stabilization on the native tetrameric structure of TTR, creating a barrier that is insurmountable under physiological conditions. Since kinetic stabilization of the TTR native state by interallelic trans suppression is known to ameliorate disease, there is reason to be optimistic that the dibenzofuran-based inhibitors will do the same. Preventing the onset of amyloidogenesis is the most conservative strategy to intervene clinically, as it remains unclear which of the TTR misassembly intermediates results in toxicity. The exceptional binding selectivity enables these inhibitors to occupy the thyroxine binding site(s) in a complex biological fluid such as blood plasma, required for inhibition of amyloidogenesis in humans. It is now established that the dibenzofuran-based amyloidogenesis inhibitors have high selectivity, affinity, and efficacy and are thus excellent candidates for further pharmacologic evaluation.

Amyloid↗
PubMed2005

A modified PCR system for amplifying beta-ketoacyl-ACP synthase gene fragments with DNA from Streptomyces luteogriseus.

Streptomyces luteogriseus strain 099, producing a new type of macrolide antibiotic with anti-coxB6 virus and anti-HIV protease activities, was isolated from soil. PCR was optimized to amplify beta-ketoacyl-ACP synthase (KS) genes. The system was optimized around the use of higher concentrations of DMSO (15% vs. 10% v/v) and dNTP (500 microM vs. 50-200 microM) and a lower annealing temperature (55 degrees C vs. 60-70 degrees C) than the normal PCR method used to amplify high GC content DNA.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed2005

Assessment of pesticide residues in two arable soils from the semi-arid and subtropical regions of China.

The residues of 31 chlorinated hydrocarbons (CHCs), 25 chlorophenols (CPs), 30 organophosphorus (OP) and pyrethroid (PRT) in two arable soils from the semi-arid and subtropical regions of China were assessed. Data obtained indicate that the main compounds of CHC pesticide residues in the semi-arid soil were 4,4'-DDE (25.3 ng/g) and beta-HCH (14.1 ng/g), which totally accounted to about 90% of total CHC residues detected. The total content of CHC residues detected in the subtropical soil was only 3.1 ng/g, of which approximately 50% was beta-HCH. However, the total content of CP residues in both of the soils was about 11 ng/g. In the semi-arid soil, only parathion-methyl amongst the 30 compounds of OP and PRT residues was detected (32.5 ng/g), whilst malathion and parathion-methyl (8.7 and 17.7 ng/g, respectively) detected in the subtropical soil. Based on these results, it was suggested the environmental risk of pesticide residues ranked in an order as CHCs (mainly as 4,4'-DDE, beta-HCH) > OP (parathion-methyl) > CPs for the semi-arid soil, and as OPs (parathion-methyl and malathion) > CPs > CHCs (beta-HCH) for the subtropical soil.

China↗
PubMed2005

New evidence that both T-type calcium channels and GABAA channels are responsible for the potent peripheral analgesic effects of 5alpha-reduced neuroactive steroids.

Neurosteroids are potent blockers of neuronal low-voltage activated (T-type) Ca(2+) channels and potentiators of GABA(A) ligand-gated channels, but their effects in peripheral pain pathways have not been studied previously. To investigate potential analgesic effects and the ion channels involved, we tested the ability of locally injected 5alpha-reduced neurosteroids to modulate peripheral thermal nociception to radiant heat in adult rats in vivo and to modulate GABA(A) and T-type Ca(2+) channels in vitro. The steroid anesthetic alphaxalone (ALPX), the endogenous neurosteroid allopregnanolone (3alpha5alphaP), and a related compound ((3alpha,5alpha,17beta)-3-hydroxyandrostane-17-carbonitrile, (ACN)), induced potent, dose-dependent, enantioselective anti-nociception in vivo and modulation of both T-type Ca(2+) currents and GABA(A)-mediated currents in vitro. Analgesic effects of ALPX were incompletely antagonized by co-injections of the GABA(A) receptor antagonist bicuculline. The neurosteroid analogue ((3alpha,5alpha)-3-hydroxy-13,24-cyclo-18,21-dinorchol-22-en-24-ol (CDNC24), a compound with GABAergic but not T-type activity, was not analgesic. However, (3beta,5alpha,17beta)-17-hydroxyestrane-3-carbonitrile (ECN)), which has effects on T-type channels but not on GABA(A) receptors, also induced potent enantioselective peripheral anti-nociception. ECN increased pain thresholds less than ALPX, 3alpha5alphaP and ACN. However, when an ineffective dose of CDNC24 was combined with ECN, anti-nociceptive activity was greatly enhanced, and this effect was bicuculline-sensitive. These results strongly suggest that GABA(A) channels do not contribute to baseline pain transmission, but they can enhance anti-nociception mediated by blockade of T-type Ca(2+) channels. In conclusion, we demonstrate that potent peripheral analgesia induced by 5alpha-reduced neurosteroid is mediated in part by effects on T-type Ca(2+) channels. Our results also reveal a role of GABA-gated ion channels in peripheral nociceptive signaling.

Anesthetics↗