On-cartridge derivatisation using matrix solid phase dispersion for the determination of cyclamate in foods.

A novel method for determination of sodium cyclamate in foods was developed. In this method, a syringe was loaded with the homogeneous mixture of the sample, KMnO4 powder and silica dispersant and used as a matrix solid phase dispersion (MSPD) reactor. As the reactor was infiltrated with small amounts of concentrated HCl, cyclamate was converted to 2-chlorocyclohexanone quickly and effectively within 5 min and determined by HPLC on a reversed-phase column using UV detection at a wavelength of 310 nm. Comparing with the traditional derivatisation in solution, the better clean-up was provided using on-cartridge derivatisation of MSPD, and much time, labor, and expense were saved. The results showed good linearity (r2 = 0.9998) over the concentration range of 1-500 mg/L. The limit of detection (LOD) and limits of quantification (LOQ) of the cyclamate were 0.3 mg/L and 1 mg/L respectively. The recoveries ranged from 91.6% to 101.3% with the relative standard deviations (RSDs) in the range of 2.5%-4.3%.

Growth differentiation factor 15 may protect the myocardium from no­reflow by inhibiting the inflammatory­like response that predominantly involves neutrophil infiltration.

The aim of the current study was to investigate the time course of the expression of growth differentiation factor­15 (GDF­15) in rat ischemic myocardium with increasing durations of reperfusion, and to elucidate its physiopathological role in the no­reflow phenomenon. Wistar rats were randomly divided into ischemia reperfusion (I/R) and sham groups, and myocardial I/R was established by ligation of the left anterior descending coronary artery for 1 h followed by reperfusion for 2, 4, 6, 12, 24 h and 7 days whilst rats in the sham group were subjected to a sham operation. The expression levels of GDF­15 and ICAM­1 were measured, in addition to myeloperoxidase (MPO) activity. The myocardial anatomical no­reflow and infarction areas were assessed. The area at risk was not significantly different following various periods of reperfusion, while the infarct area and no­reflow area were significantly greater following 6 h of reperfusion (P<0.05). The mRNA and protein expression levels of GDF­15 were increased during the onset and development of no­reflow, and peaked following 24 h of reperfusion. MPO activity was reduced with increasing reperfusion duration, while ICAM­1 levels were increased. Hematoxylin and eosin staining demonstrated that myocardial neutrophil infiltration was significantly increased by I/R injury, in particular following 2, 4 and 6 h of reperfusion. GDF­15 expression levels were negatively correlated with MPO activity (r=­0.55, P<0.001), and the MPO activity was negatively correlated with the area of no­reflow (r=­0.46, P<0.01). By contrast, GDF­15 was significantly positively correlated with ICAM­1 levels (r=0.52, P<0.01), which additionally were demonstrated to be significantly positively associated with the size of the no­reflow area (r=0.39, P<0.05). The current study demonstrated the time course effect of reperfusion on the expression of GDF­15 in the myocardial I/R rat model, with the shorter reperfusion times (6 h) resulting in significant no­reflow in ischemic myocardium. GDF­15 may protect the I/R myocardium from no­reflow by inhibiting the inflammatory­like response, which involves neutrophil infiltration and transendothelial migration.

HIV, syphilis, and behavioral risk factors among female sex workers before and after implementation of harm reduction programs in a high drug-using area of China.

OBJECTIVE: To evaluate the impact of harm reduction programs on HIV and syphilis infection and related risk behaviors among female sex workers (FSWs) in a drug trafficking city in Southwest China. DESIGN: Before and after harm reduction program study. METHODS: Two cross-sectional surveys were conducted among FSWs before and after harm reduction programs were launched in Xichang city, Sichuan province. The first and second cross-sectional surveys were conducted in 2004 and 2010, respectively. Temporal changes in odds of HIV, syphilis, and behavioral risk factors were assessed by multivariable logistic regression while controlling for socio-demographics. RESULTS: The 2004 and 2010 cross-sectional surveys recruited 343 and 404 FSWs, respectively. From 2004 to 2010, the odds of syphilis infection decreased by 35% and was of borderline statistical significance (AOR: 0.65, 95% CI: 0.41-1.03), while odds of HIV infection rose, but not significantly (AOR: 4.12, 95% CI: 0.76-22.45). Although odds of unprotected sex with primary sex partners did not significantly change over time (AOR: 0.96; 95% CI: 0.61-1.50), odds of unprotected sex with clients declined significantly and remarkably (AOR: 0.14, 95% CI: 0.09-0.21). Notably, the odds of reporting ≥10 new sex partners in the previous month increased by 37% (AOR: 1.37; 95% CI: 0.98-1.90). CONCLUSIONS: Harm reduction strategies may be an effective means of reducing unprotected sex with clients among FSWs. Future research is needed to better target both FSWs and IDUs and interrupt bridging networks for HIV transmission in high drug-using areas of China.

[Dynamic expression of toll like receptor 2 and 4 in a rat model of myocardial ischemia/reperfusion injury].

OBJECTIVE: To explore the role of toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) in myocardial ischemia/reperfusion injury (MI/RI) by observing the dynamic expression changes at mRNA and protein levels early after myocardial ischemia/reperfusion (I/ R). METHODS: The Wistar rats were randomly divided into Sham and I/R group (n = 42), and killed according to different reperfusion time (1, 2, 4, 6, 12, 24 h and 7 d). Structural and morphous changes of myocytes were observed under optical microscope. The mRNA and protein levels of TLR2 and TLR4 were detected using real-time PCR (RT-PCR). Monocyte chemokine protein-1 (MCP-1) and interleukine-6 (IL-6) mRNA levels were measured by reverse transcriptase-polymerase chain reaction (rt-PCR). RESULTS: (1) With the extension of reperfusion time, the myocardial infarct size increased smoothly, and reached the plateau at 4 h, then stayed in the platform. After reperfusion for 7 d, the ventricular had been remodeled. (2) At the beginning of reperfusion, myocardial structure showed no significant change in Sham group, but had different degrees of injury in I/R group. In rats of the group reperfused for 7 d the left ventricular remodeling could be visible. (3) Compared to sham group,TIR2, TLR4, MCP-1, IL-6 mRNA level were increased in myocardium in I/R group. TLR2 and TLR4 both peaked at 4 h of reperfusion, IL6 peaked at 6 h, followed by a gradually decrease. TLR4 and IL-6 mRNA levels rose again at 7 d. MCP-1 level in I/R group remained fairly with sham group at the beginning of reperfusion, and markedly elevated at 7 d. CONCLUSION: Expression of TLRs mRNA in myocardium during early after myocardial ischemia/reperfusion increased rapidly and activated TLRs might play an important role in MI/RI through promoting the generation of inflammatory factors. At the late reperfusion, TLRs levels raise again and the expression of inflammatory factors increase once again, Those may probably affect the remodeling of ventricular, and injure myocardial structure and function.

RTEL1 and TERT polymorphisms are associated with astrocytoma risk in the Chinese Han population.

Common variants of multiple genes play a role in glioma onset. However, research related to astrocytoma, the most common primary brain neoplasm, is rare. In this study, we chose 21 tagging SNPs (tSNPs), previously reported to be associated with glioma risk in a Chinese case-control study from Xi'an, China, and identified their contributions to astrocytoma susceptibility. We found an association with astrocytoma susceptibility for two tSNPs (rs6010620 and rs2853676) in two different genes: regulator of telomere elongation helicase 1 (RTEL1) and telomerase reverse transcriptase (TERT), respectively. We confirmed our results using recessive, dominant, and additive models. In the recessive model, we found two tSNPs (rs2297440 and rs6010620) associated with increased astrocytoma risk. In the dominant model, we found that rs2853676 was associated with increased astrocytoma risk. In the additive model, all three tSNPs (rs2297440, rs2853676, and rs6010620) were associated with increased astrocytoma risk. Our results demonstrate, for the first time, the potential roles of RTEL1 and TERT in astrocytoma development.

Evaluation of harm reduction programs on seroincidence of HIV, hepatitis B and C, and syphilis among intravenous drug users in southwest China.

OBJECTIVE: The aim of this study was to evaluate the impact of a multifaceted harm reduction program by comparing seroincidence rates of HIV, hepatitis C virus (HCV), hepatitis B virus (HBV), and syphilis before and after implementation of harm reduction strategies among intravenous drug users (IDUs) in a drug-trafficking city in Southwest China. DESIGN: This is a prospective cohort study with 24 months of follow-up. METHODS: Two prospective cohorts (cohort 2002-2004 and cohort 2006-2008) were followed up every 6 months for seroconversions of HIV, HCV, and syphilis antibodies and HBV surface antigen. RESULTS: After implementation of harm reduction strategies in Xichang city, Sichuan province, the HIV incidence rate among IDUs significantly dropped from 2.5 to 0.6 cases per 100 person-years. Subanalyses also indicated that the incidence rate of HBV significantly declined from 14.2 to 8.8 cases per 100 person-years. No significant changes in the seroincidence rates of HCV or syphilis were detected after implementation of IDU harm reduction strategies. CONCLUSIONS: Harm reduction strategies may help reduce the high incidence of certain blood-borne infectious diseases and sexual transmitted diseases among high-risk IDUs in southwest China. Additional research is needed on the implementation and evaluation of harm reduction strategies in China.

Common single nucleotide polymorphisms and keratoconus in the Han Chinese population.

OBJECTIVE: To investigate whether the tag single nucleotide polymorphisms (tSNPs) in VSX1, COL4A3, COL4A4, IL1A and IL1B genes were associated with keratoconus (KTCN) in the Han Chinese population. METHODS: Ninety-seven KTCN patients and 101 healthy controls were enrolled in this study. All cases were diagnosed on the basis of clinical examination. Twenty-one tSNPs were selected for association study in five genes. SNP genotyping was performed by Sequenom MassARRAY RS1000. Sequenom Typer 4.0 Software, PLINK, Haploview and SHEsis software platform were used to perform data management and analyses. RESULTS: Three tSNPs in the VSX1 gene were observed to be associated with KTCN risk at a 5% level by χ(2) test (rs56157240 and rs12480307, p = 0.0499, OR: 6.42, 95% CI: 0.77-53.78; rs6050307, p = 1.22 × 10(-7), OR: 0.05, 95% CI: 0.01-0.23). Rs2071376 in the IL1A gene was also associated with KTCN (p = 0.0487, OR: 1.51, 95% CI: 1.00-2.26). Three haplotypes in the VSX1 gene were found to be associated with risk of KTCN (p < 0.05). CONCLUSIONS: Our findings confirmed previous reports that polymorphisms of VSX1 and IL1A genes were associated with risk of KTCN in the Chinese population, suggesting an important determinant of KTCN development by VSX1 and IL1A genes.

Gender and ethnic disparities of HIV and syphilis seroconversions in a 4-year cohort of injection drug users.

This study assessed gender and ethnic disparities of HIV and syphilis seroconversions in a cohort of injection drug users (IDUs) in Southwest China. A cohort of HIV-seronegative IDUs was followed up from November 2002 to January 2007. The average seroincidence for HIV and syphilis was 2.2 and 4.2 per 100 person-years (PYs), respectively. Multivariable Poisson regression models indicated that the predictors for incident HIV seroconversion included non-Han minority ethnic groups (RR: 5.2; 95% CI: 1.9-14.4) and injecting drugs > or = 7 times/week in the past 3 months (RR: 3.6; 95% CI: 1.4-9.8). The predictors for incident syphilis seroconversion included female (RR: 4.1; 95% CI: 1.8-9.3) and being married or cohabiting (RR: 2.7; 95% CI: 1.2-5.9). These findings suggested that HIV continues to spread among IDUs, especially among Yi and other minority ethnic groups, and frequent risky injections might be the major diver of the epidemic. Female IDUs are disproportionally affected by syphilis. Further research is needed to better understand the ethnicity disparity for HIV and gender disparity for syphilis.

Factors Associated with Recent Risky Drug Use and Sexual Behaviors among Drug Users in Southwestern China.

A cross-sectional survey was conducted in 2007 among 504 drug users who were recruited mainly from detoxification centers in southwest China. About one-third (34.3%) of participants reported recent risky drug use behavior, which was defined as injecting drugs in the past 3 months, and more than one-fifth (21.6%) reported recent risky sexual behavior, or had multiple sexual partners in the past 30 days. Male sex (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.2-3.2) and more episodes of detoxification (OR, 3.7; 95% CI, 2.3-6.0) were associated with higher odds of risky drug use behavior, while unmarried status (OR, 1.7; 95% CI, 1.0-2.9), higher personal annual income (OR, 1.8; 95% CI, 1.1-2.8) and history of sexually transmitted infections (OR, 3.7; 95% CI, 2.1-6.6) were associated with higher odds of having risky sexual behavior. Subgroup analyses showed 15% participants who used drugs in the past 3 months also shared needles, and 77% participants who had multiple sexual partners in the past 30 days did not use condoms during sex with non-primary sexual partners. The study findings are useful for developing HIV risk reduction intervention programs among drug users.

Kringle 5 of human plasminogen suppresses hepatocellular carcinoma growth both in grafted and xenografted mice by anti-angiogenic activity.

Plasminogen kringle 5 (K5), a proteolytic fragment of plasminogen, is an endogenous angiogenic inhibitor. We have previously shown that K5 inhibits ischemia-induced retinal neovascularization in a rat model. However, its anti-angiogenic potential and application in the treatment of neoplastic diseases have not been well investigated. Our present study was designed to test its effect on the neovascularization and growth of hepatocellular carcinoma, a typical hypervascular tumor. Recombinant human K5 was expressed in E. coli and purified by affinity chromatography. K5 inhibited proliferation and induced apoptosis of primary endothelial cells in dose-dependent manner, but no effect on pericytes from the same origin of endothelial cells, which suggested an endothelial cell-specific inhibition. Moreover, K5 had no effect on the proliferation and apoptosis of mouse HepA and human Bel7402 hepatoma cell lines even in the enhanced concentration range, which suggested K5 having no direct effect on tumor cells. Ventral injection of K5 significantly suppressed the tumor growth in graphed hepatocarcinoma mice model, which was established by injection of mouse HepA hepatoma cells. In xenografted hepatocarcinoma athymic mice model, which mimicked human tumors by injection of human Bel7402 hepatoma cells, K5 significantly suppressed the tumor growth. An average of 68% suppression of primary tumor growth was observed in the K5-treated mice compared with control group. K5 also inhibited intratumoral neovascularization in the two cancer models determined by micro vessel density (MVD) analysis. Injection of K5 significantly induced the cleavage of pro-caspase-3 in tumor tissues of grafted mouse model, which suggested K5 also induced apoptosis of tumor tissues and the decreased intratumoral microvascular density in K5 treated group may correlate with K5-induced endothelial cell apoptosis. These results suggest that tumor growth suppression of K5 depends on its anti-angiogenic activity and K5 could have therapeutic potential in hepatocellular carcinoma.

[High-dose glucose induces human retinal endothelial cell apoptosis].

OBJECTIVE: To examine the direct effect of high glucose levels on primary cultured human retinal capillary endothelial cells (HRCEC). METHODS: HRCECs were isolated from donated eyes and cultured for 6 days in the media containing 5 or 25 mmol/L glucose. The cell viability was determined by trypan blue exclusion assay and cell cycle analyzed by flow cytometry, with the cell apoptosis assayed by TUNEL method. RESULTS: The cell viability was significantly decreased after exposure to 25 mmol/L glucose, and the number of apoptotic cells determined by flow cytometry and TUNEL was significantly increased in response to high-dose glucose treatment. CONCLUSION: High-dose glucose induces apoptosis in HRCEC, which may contribute to the development of diabetic retinopathy.