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1.  Nanomechanics of phospholipid LB film studied layer by layer with AFM 
Phospholipid, a main component of cell membrane, has been explored as a model system of the cell membrane and temporary scaffold materials in recent studies. The mechanical properties of phospholipid layers are essentially interesting since it is involved in several biological processes.
Here, the nanomechanical properties such as indentation force, adhesion force and DMT (Derjaguin-Müller-Toporov) modulus of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) Langmuir-Blodgett (LB) films were analyzed layer by layer with Atomic Force Microscope (AFM) under deionized water condition.
The penetration distances in the indentation force curves are equal to the thicknesses of phospholipid films, and the yield forces of DSPC LB films in deionized water are smaller than that of similar lipid films in buffered solutions due to the influence of ions. Moreover, the DMT modulus of upper layer DSPC LB film is different from that of monolayer DSPC LB film due to the influence of their different substrates. Our results suggest that environment such as surrounding ions and substrate will strongly influence the measured nano-mechanical properties of the lipid bilayer, especially that of the down layer.
Graphical AbstractA process about the exploration of nanomechanics of DSPC LB film.
PMCID: PMC4279057  PMID: 25614761
Phospholipid; Nanomechanics; Langmuir-Blogget film; Atomic force microscope; Indentation force curve
2.  Nanomechanics of phospholipid LB film studied layer by layer with AFM 
Phospholipid, a main component of cell membrane, has been explored as a model system of the cell membrane and temporary scaffold materials in recent studies. The mechanical properties of phospholipid layers are essentially interesting since it is involved in several biological processes.
Here, the nanomechanical properties such as indentation force, adhesion force and DMT (Derjaguin-Müller-Toporov) modulus of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) Langmuir-Blodgett (LB) films were analyzed layer by layer with Atomic Force Microscope (AFM) under deionized water condition.
The penetration distances in the indentation force curves are equal to the thicknesses of phospholipid films, and the yield forces of DSPC LB films in deionized water are smaller than that of similar lipid films in buffered solutions due to the influence of ions. Moreover, the DMT modulus of upper layer DSPC LB film is different from that of monolayer DSPC LB film due to the influence of their different substrates. Our results suggest that environment such as surrounding ions and substrate will strongly influence the measured nano-mechanical properties of the lipid bilayer, especially that of the down layer.
Graphical AbstractA process about the exploration of nanomechanics of DSPC LB film.
PMCID: PMC4279057  PMID: 25614761
Phospholipid; Nanomechanics; Langmuir-Blogget film; Atomic force microscope; Indentation force curve
3.  Acceptance of Male Circumcision Among Male Rural-to-Urban Migrants in Western China 
AIDS Research and Human Retroviruses  2013;29(12):1582-1588.
To describe the acceptability of male circumcision (MC) and explore potential factors associated with MC acceptability among male rural-to-urban migrants in western China, a cross-sectional survey of MC acceptability was conducted with 1,904 subjects in three western provinces with high HIV prevalence (Guangxi, Chongqing, and Xinjiang) in China between June 2009 and November 2009. Through face-to-face interviews, the participants completed a self-administered questionnaire about demographics, MC knowledge, willingness and reasons to accept or refuse MC, sexual behaviors, and other psychosocial variables. Factors associated with acceptability of MC were identified by multiple logistic regression analysis. Of the participants (n=1,904), 710 men were willing to accept MC (37.3%); the reasons included promotion of the partners' genital hygiene (54.9%), redundant prepuce or phimosis (43.1%), enhancement of sexual pleasure (40.6%), prevention of penile inflammation or cancer (35.5%), and protection against HIV and sexual transmitted diseases (STDs)(31.1%). A multivariable logistic regression showed that four factors were associated with acceptability of MC, including education level (OR=1.286, 95% CI=1.025∼1.614), redundant prepuce or phimosis (OR=13.751, 95% CI=10.087∼18.745), having one or more circumcised friends (OR=2.468, 95% CI=1.953∼3.119), and having sexual intercourse with a temporary partner in the past year (OR=1.543, 95% CI=1.101∼2.162). Compared with previously published data among the general population in China or worldwide, the acceptability of MC (37.3%) was low among the male rural-to-urban migrants in western China. Nevertheless, appropriate education could greatly improve the acceptability of MC. More public campaigns and health education on MC are needed to increase the rate of MC in China.
PMCID: PMC3848437  PMID: 23931654
4.  Development of a Surface Plasmon Resonance Biosensing Approach for the Rapid Detection of Porcine Circovirus Type2 in Sample Solutions 
PLoS ONE  2014;9(10):e111292.
A sensitive and label-free analytical approach for the detection of porcine circovirus type 2 (PCV2) instead of PCV2 antibody in serum sample was systematically investigated in this research based on surface plasmon resonance (SPR) with an establishment of special molecular identification membrane. The experimental device for constructing the biosensing analyzer is composed of an integrated biosensor, a home-made microfluidic module, and an electrical control circuit incorporated with a photoelectric converter. In order to detect the PCV2 using the surface plasmon resonance immunoassay, the mercaptopropionic acid has been used to bind the Au film in advance through the known form of the strong S-Au covalent bonds formed by the chemical radical of the mercaptopropionic acid and the Au film. PCV2 antibodies were bonded with the mercaptopropionic acid by covalent -CO-NH- amide bonding. For the purpose of evaluating the performance of this approach, the known concentrations of PCV2 Cap protein of 10 µg/mL, 7.5 µg/mL, 5 µg/mL, 2.5 µg/mL, 1 µg/mL, and 0.5 µg/mL were prepared by diluting with PBS successively and then the delta response units (ΔRUs) were measured individually. Using the data collected from the linear CCD array, the ΔRUs gave a linear response over a wide concentration range of standard known concentrations of PCV2 Cap protein with the R-Squared value of 0.99625. The theoretical limit of detection was calculated to be 0.04 µg/mL for the surface plasmon resonance biosensing approach. Correspondingly, the recovery rate ranged from 81.0% to 89.3% was obtained. In contrast to the PCV2 detection kits, this surface plasmon resonance biosensing system was validated through linearity, precision and recovery, which demonstrated that the surface plasmon resonance immunoassay is reliable and robust. It was concluded that the detection method which is associated with biomembrane properties is expected to contribute much to determine the PCV2 in sample solutions instead of PCV2 antibody in serum samples quantitatively.
PMCID: PMC4213070  PMID: 25354302
5.  Plasma proteomics for the identification of Alzheimer’s disease 
Alzheimer disease and associated disorders  2013;27(4):10.1097/WAD.0b013e31827b60d2.
Less invasive biomarkers for early Alzheimer’s disease (AD) are urgently needed. The present study aimed to establish a panel of plasma proteins that accurately distinguishes early AD from physiological aging and to compare the findings with previous reports. Fifty eight healthy controls (CON) and 109 patients with AD dementia were randomly split into a training (40%) and a test (60%) sample. Significant proteins to differentiate between the CON and the AD dementia groups were identified in a comprehensive panel of 107 plasma analytes in the training sample; the accuracy in differentiating these two groups was explored in the test sample. A set of five plasma proteins was identified, which differentiated the CON vs. the AD dementia with a sensitivity of 89.36% and a specificity of 79.17%. A biological pathway analysis showed that four of the five proteins belonged to a common network with amyloid precursor protein and tau. Apolipoprotein E was the only protein that was both significant in the present report and in one previous proteomic study. The study provides a piece of evidence in support of the feasibility of a blood-based biomarker approach in AD diagnostics; however, further research is required because of issues with replicability.
PMCID: PMC3626738  PMID: 23314060
Alzheimer’s disease; dementia; biomarker; early diagnosis; prognosis; proteomics
6.  Fabrication of Graphene-isolated-Au-nanocrystal Nanostructures for Multimodal Cell Imaging and Photothermal-enhanced Chemotherapy 
Scientific Reports  2014;4:6093.
Using nanomaterials to develop multimodal systems has generated cutting-edge biomedical functions. Herein, we develop a simple chemical-vapor-deposition method to fabricate graphene-isolated-Au-nanocrystal (GIAN) nanostructures. A thin layer of graphene is precisely deposited on the surfaces of gold nanocrystals to enable unique capabilities. First, as surface-enhanced-Raman-scattering substrates, GIANs quench background fluorescence and reduce photocarbonization or photobleaching of analytes. Second, GIANs can be used for multimodal cell imaging by both Raman scattering and near-infrared (NIR) two-photon luminescence. Third, GIANs provide a platform for loading anticancer drugs such as doxorubicin (DOX) for therapy. Finally, their NIR absorption properties give GIANs photothermal therapeutic capability in combination with chemotherapy. Controlled release of DOX molecules from GIANs is achieved through NIR heating, significantly reducing the possibility of side effects in chemotherapy. The GIANs have high surface areas and stable thin shells, as well as unique optical and photothermal properties, making them promising nanostructures for biomedical applications.
PMCID: PMC4151100  PMID: 25178354
7.  Methamphetamine Inhibits Toll-Like Receptor 9-Mediated Anti-HIV Activity in Macrophages 
AIDS Research and Human Retroviruses  2013;29(8):1129-1137.
Toll-like receptor 9 (TLR9) is one of the key sensors that recognize viral infection/replication in the host cells. Studies have demonstrated that methamphetamine (METH) dysregulated host cell innate immunity and facilitated HIV infection of macrophages. In this study, we present new evidence that METH suppressed TLR9-mediated anti-HIV activity in macrophages. Activation of TLR9 by its agonist CpG-ODN 2216 inhibits HIV replication, which was demonstrated by increased expression of TLR9, interferon (IFN)-α, IFN regulatory factor-7 (IRF-7), myeloid differentiation factor 88 (MyD88), and myxovirus resistance gene A (MxA) in macrophages. However, METH treatment of macrophages greatly compromised the TLR9 signaling-mediated anti-HIV effect and inhibited the expression of TLR9 downstream signaling factors. Dopamine D1 receptor (D1R) antagonists (SCH23390) could block METH-mediated inhibition of anti-HIV activity of TLR9 signaling. Investigation of the underlying mechanisms of the METH action showed that METH treatment selectively down-regulated the expression of TLR9 on macrophages, whereas it had little effect on the expression of other TLRs. Collectively, our results provide further evidence that METH suppresses host cell innate immunity against HIV infection by down-regulating TLR9 expression and its signaling-mediated antiviral effect in macrophages.
PMCID: PMC3715810  PMID: 23751096
8.  Silencing DACH1 Promotes Esophageal Cancer Growth by Inhibiting TGF-β Signaling 
PLoS ONE  2014;9(4):e95509.
Human Dachshund homologue 1 (DACH1) is a major component of the Retinal Determination Gene Network. Loss of DACH1 expression was found in breast, prostate, lung, endometrial, colorectal and hepatocellular carcinoma. To explore the expression, regulation and function of DACH1 in human esophageal cancer, 11 esophageal cancer cell lines, 10 cases of normal esophageal mucosa, 51 cases of different grades of dysplasia and 104 cases of primary esophageal squamous cancer were employed. Methylation specific PCR, immunohistochemistry, western blot, flow cytometry, small interfering RNAs, colony formation techniques and xenograft mice model were used. We found that DACH1 expression was regulated by promoter region hypermethylation in esophageal cancer cell lines. 18.8% (6 of 32) of grade 1, 42.1% (8 of 19) of grade 2 and grade 3 dysplasia (ED2,3), and 61.5% (64 of 104) of esophageal cancer were methylated, but no methylation was found in 10 cases of normal esophageal mucosa. The methylation was increased in progression tendency during esophageal carcinogenesis (P<0.01). DACH1 methylation was associated with poor differentiation (P<0.05) and late tumor stage (P<0.05). Restoration of DACH1 expression inhibited cell growth and activated TGF-β signaling in KYSE150 and KYSE510 cells. DACH1 suppressed human esophageal cancer cell tumor growth in xenograft mice. In conclusion, DACH1 is frequently methylated in human esophageal cancer and methylation of DACH1 is involved in the early stage of esophageal carcinogenesis. DACH1 expression is regulated by promoter region hypermethylation. DACH1 suppresses esophageal cancer growth by activating TGF-β signaling.
PMCID: PMC3990688  PMID: 24743895
9.  Potential of Adipose-Derived Mesenchymal Stem Cells and Skeletal Muscle-Derived Satellite Cells for Somatic Cell Nuclear Transfer Mediated Transgenesis in Arbas Cashmere Goats 
PLoS ONE  2014;9(4):e93583.
Somatic cell nuclear transfer is used to generate genetic models for research and new, genetically modified livestock varieties. Goat fetal fibroblast cells (gFFCs) are the predominant nuclear donors in Cashmere goat transgenic cloning, but have disadvantages. We evaluated the potential of goat adipose-derived mesenchymal stem cells (gADSCs) and goat skeletal muscle-derived satellite cells (gMDSCs) for somatic cell nuclear transfer, evaluating their proliferation, pluripotency, transfection efficiency and capacity to support full term development of embryos after additive gene transfer or homologous recombination. gADSCs and gMDSCs were isolated by enzyme digestion and differentiated into neurocytes, myotube cells and insulin-producing cells. Neuron-specific enolase, fast muscle myosin and insulin expression were determined by immunohistochemistry. Following somatic cell nuclear transfer with donor cells derived from gADSCs, gMDSCs and gFFCs, transfection and cloning efficiencies were compared. Red fluorescent protein levels were determined by quantitative PCR and western blotting. 5-Methylcytosine, H4K5, H4K12 and H3K18 were determined immunohistochemically. gADSCs and gMDSCs were maintained in culture for up to 65 passages, whereas gFFCs could be passaged barely more than 15 times. gADSCs and gMDSCs had higher fluorescent colony forming efficiency and greater convergence (20%) and cleavage (10%) rates than gFFCs, and exhibited differing H4K5 histone modification patterns after somatic cell nuclear transfer and in vitro cultivation. After transfection with a pDsRed2-1 expression plasmid, the integrated exogenous genes did not influence the pluripotency of gADSCs–pDsRed2-1 or gMDSCs–pDsRed2-1. DsRed2 mRNA expression by cloned embryos derived from gADSCs–pDsRed2-1 or gMDSCs–pDsRed2-1 was more than twice that of gFFCs–pDsRed2-1 embryos (P<0.01). Pregnancy rates of gADSCs–pDsRed2-1 and gMDSCs–pDsRed2-1 recipients were higher than those of gFFCs–pDsRed2-1 recipients (P<0.01). With their high proliferative capacity and transfection efficiency, gADSCs and gMDSCs are a valuable cell source for breeding new, genetically modified varieties of livestock by somatic cell nuclear transfer.
PMCID: PMC3974752  PMID: 24699686
10.  Prevalence and Correlates of Sexual Risk Behaviors Among Drug Users in Western China: Implications for HIV Transmission 
The prevalence and correlates of sexual risk behaviors among drug users in western China and the implications for HIV transmission in this population are described. A cross-sectional survey of male drug users was conducted in methadone maintenance therapy clinics and detoxification centers in three western provinces of China between September 2009 and December 2010. Participants in the study completed a questionnaire about demographics, HIV/AIDS knowledge, drug use history, sexual risk behaviors, and other psychosocial variables. Factors associated with HIV sexual risk behaviors were identified by multiple logistic regression analysis. Of 1,304 drug users surveyed, nearly 54% never used condoms during sexual intercourse with a spouse or cohabitant, and this behavior was associated with coming from Chongqing (OR=1.86, p<0.05), being aged 36 and older (OR=5.03, p<0.05), being married or cohabiting (OR=1.68, p<0.05), having first taken drugs at age 30 and above (OR=1.80, p<0.05), and having received AIDS advice or detection from authorities in the past year (OR=1.95, p<0.05). Twenty-six percent had had sex with casual sexual partners in the past year, and this behavior was associated with being married or cohabiting (OR=0.30, p<0.05), first taking drugs at age 31 and above (OR=0.42, p<0.05), and receiving AIDS advice or HIV detection from authorities in the past year (OR=0.70, p<0.05). About 34% never used a condom when having sex with casual sexual partners, and this behavior was associated with coming from Guangxi (OR=2.81, p<0.05) or Chongqing (OR=2.73, p<0.05). Almost 14% had had commercial sex in the past year, and this behavior was associated with coming from Guangxi (OR=6.26, p<0.05) or Chongqing (OR=5.44, p<0.05) and having exchanged needles or received clean needles from the Needle Exchange Centers in the past year (OR=2.76, p<0.05). Nearly 23% had never used condoms when having commercial sex, and this behavior was associated with having received free condoms from authorities in the past year (OR=0.26, p<0.05). Sexual risk behaviors among drug users in Guangxi, Chongqing, and Xinjiang are common. Additional intervention strategies are needed to control the spread of HIV in this population.
PMCID: PMC3607904  PMID: 23210514
11.  Exploring the complex mechanical properties of xanthan scaffolds by AFM-based force spectroscopy 
The polysaccharide xanthan has been extensively studied owing to its potential application in tissue engineering. In this paper, xanthan scaffold structures were investigated by atomic force microscope (AFM) in liquid, and the mechanical properties of the complex xanthan structures were investigated by using AFM-based force spectroscopy (FS). In this work, three types of structures in the xanthan scaffold were identified based on three types of FS stretching events. The fact that the complex force responses are the combinations of different types of stretching events suggests complicated intermolecular interactions among xanthan fibrils. The results provide crucial information to understand the structures and mechanical properties of the xanthan scaffold.
PMCID: PMC3999747  PMID: 24778961
atomic force microscopy (AFM); force spectroscopy (FS); mechanical properties; xanthan scaffold
12.  Attitudes Toward HIV Pre-Exposure Prophylaxis Among Men Who Have Sex with Men in Western China 
AIDS Patient Care and STDs  2013;27(3):137-141.
Pre-exposure prophylaxis (PrEP), as demonstrated in recently published clinical trials, is one promising approach for controlling the emerging epidemic among men who have sex with men (MSM). We evaluated the attitudes towards use of PrEP among MSM in western China. A total of 1402 participants completed a self-administered questionnaire. Overall, 22% of the participants reported that they had heard of PrEP, <1% had ever used medicine to prevent HIV, and 64% reported that they were absolutely willing to use PrEP if it were proven to be safe and effective. The predictors of willingness to use PrEP included lower education, moderate income compared with the lowest income, never or rarely finding sexual partners through the Internet in the past 6 months, sexually transmitted infection (STI) history, more knowledge of AIDS, worrying about HIV as a threat to themselves and their family, having previously heard of PrEP, and believing that PrEP was effective in preventing HIV. This study demonstrates that Chinese MSM have moderate awareness of PrEP and a high interest in using it.
PMCID: PMC3595955  PMID: 23425017
13.  Scientific publications in respiratory journals from Chinese authors in various parts of North Asia: a 10-year survey of literature 
BMJ Open  2014;4(2):e004201.
Respiratory disease remains one of the leading causes of morbidity and mortality in China. However, little is known about the research status of respirology in three major regions of China—Mainland (ML), Hong Kong (HK) and Taiwan (TW). A 10-year survey of literature was conducted to compare the three regions’ outputs in the research of respirology.
A bibliometric study.
Participants and outcome measures
A literature search in PubMed database, updated as of September 2012, led to the identification of the related articles from 2000 to 2009. The number of total articles, randomised controlled trials, case reports, meta-analysis, impact factors (IF), citations and articles published in top general medicine journals was collected for quantity and quality comparisons.
2208 articles were collected, 814 from ML, 909 from TW and 485 from HK. The total number of articles from the three regions has increased significantly from 2000 to 2009. The number of articles published per year from ML has exceeded that from HK in 2005 and TW in 2008. The accumulated IF of articles from TW (3192.417) was much higher than that from ML (2409.956) and HK (1898.312). HK got the highest average IF of respirology articles and the majority of articles were published in top general medicine journals.
The total number of published articles from the three major regions of China has increased notably from 2000 to 2009. The annual number of publications by ML researchers exceeded those from TW and HK. However, the quality of articles from TW and HK is better than that from ML.
PMCID: PMC3939649  PMID: 24583761
Internal Medicine; Medical History; Respiratory Medicine (see Thoracic Medicine)
14.  LRP-1 polymorphism is associated with global and regional amyloid load in Alzheimer's disease in humans in-vivo 
NeuroImage : Clinical  2014;4:411-416.
Impaired amyloid clearance has been proposed to contribute to β-amyloid deposition in sporadic late-onset Alzheimer's disease (AD). Low density lipoprotein receptor-related protein 1 (LRP-1) is involved in the active outward transport of β-amyloid across the blood–brain barrier (BBB). The C667T polymorphism (rs1799986) of the LRP-1 gene has been inconsistently associated with AD in genetic studies.
We aimed to elucidate the association of this polymorphism with in-vivo brain amyloid load of AD patients using amyloid PET with [11C]PiB.
Materials and methods
72 patients with very mild to moderate AD were examined with amyloid PET and C667T polymorphism was obtained using TaqMan PCR assays. The association of C667T polymorphism with global and regional amyloid load was calculated using linear regression and voxel based analysis, respectively. The effect of the previously identified modulator of amyloid uptake, the apolipoprotein E genotype, on this association was also determined.
The regression analysis between amyloid load and C667T polymorphism was statistically significant (p = 0.046, β = 0.236). In an additional analysis ApoE genotype and gender were identified to explain further variability of amyloid load. Voxel based analysis revealed a significant (p < 0.05) association between C667T polymorphism and amyloid uptake in the temporo-parietal cortex bilaterally. ApoE did not interact significantly with the LRP-1 polymorphism.
In conclusion, C667T polymorphism of LRP-1 is moderately but significantly associated with global and regional amyloid deposition in AD. The relationship appears to be independent of the ApoE genotype. This finding is compatible with the hypothesis that impaired amyloid clearance contributes to amyloid deposition in late-onset sporadic AD.
•Impaired drainage systems are discussed to be causative for AD.•LRP-1 transports Aß from the brain.•LRP-1 polymorphism is associated with amyloid deposition in-vivo in-human.•Results are compatible with the hypothesis of impaired drainage systems in AD.
PMCID: PMC3939495  PMID: 24596678
Alzheimer's disease (AD); Low density lipoprotein receptor related protein 1 (LRP-1); C667T polymorphism; Apolipoprotein E (ApoE); Pittsburgh compound B ([11C]PiB); Positron emission tomography (PET)
15.  Pre-Exposure Prophylaxis for the Prevention of HIV Infection in High Risk Populations: A Meta-Analysis of Randomized Controlled Trials 
PLoS ONE  2014;9(2):e87674.
Nearly ten randomized controlled trials (RCTs) of pre-exposure prophylaxis (PrEP) have been completed or are ongoing worldwide to evaluate the effectiveness of PrEP in HIV transmission among HIV-uninfected high risk populations. The purpose of this study was to evaluate the role of PrEP to prevent HIV transmission through a Mata-analysis.
A comprehensive computerized literature search was carried out in PubMed, EMbase, Ovid, Web of Science, Science Direct, Wan Fang, CNKI and related websites to collect relevant articles (from their establishment date to August 30, 2013). The search terms were “pre-exposure prophylaxis”, “high risk population”, “HIV infection”, “reduction”, “relative risk” and “efficacy”. We included any RCT assessing PrEP for the prevention of HIV infection in high risk populations. Interventions of the studies were continuously daily or intermittent doses of single or compound antiretrovirals (ARVs) before HIV exposure or during HIV exposure. A meta-analysis was conducted using Stata 10.0. A random-effects method was used to calculate the pooled relative risk (RR) and 95% confidence intervals (CI) for all studies included.
Seven RCTs involving 14,804 individuals in high risk populations were eligible for this study. The number of subjects in the experimental groups was 8,195, with HIV infection rate of 2.03%. The number of subjects in the control groups was 6,609, with HIV infection rate of 4.07%. The pooled RR was 0.53 (95% CI = 0.40∼0.71, P<0.001). The re-analyzed pooled RR were 0.61 (95% CI = 0.48∼0.77, P<0.001), 0.49 (95% CI = 0.38∼0.63, P<0.001), respectively, by excluding the largest study or two studies without statistical significance. Publication bias analysis revealed a symmetry funnel plot. The fail-safe number was 1,022.
These results show that PrEP is an effective strategy for reducing new HIV infections in high risk populations.
PMCID: PMC3912017  PMID: 24498350
16.  HIV Pre-Exposure Prophylaxis Interest among Female Sex Workers in Guangxi, China 
PLoS ONE  2014;9(1):e86200.
Acceptability of pre-exposure prophylaxis (PrEP) and willingness to participate in a clinical trial for both safety and efficacy of PrEP were investigated among female sex workers (FSWs) in Guangxi, China.
A cross-sectional study was performed in three cities in Guangxi. Structured, self-administered questionnaires were used to assess the acceptability of PrEP and the willingness to participate in a clinical trial. Multivariable logistic regression models were fitted to identify predictors.
Among 405 participants, 15.1% had heard of PrEP. If PrEP was deemed to be effective, safe and provided for free, 85.9% reported that they would accept it, and 54.3% of those who accepted PrEP said that they would participate in a clinical trial. The increased acceptability of PrEP was associated with working in male dominated venues, higher income, a poor family relationship, better HIV/AIDS knowledge, not realizing HIV risk from unfamiliar clients, not being forced to use condoms by the gatekeepers, consistent use of condoms, and use of drugs to prevent STD infection. The increased willingness to participate in a clinical trial was associated with a poor family relationship, better HIV/AIDS knowledge, not realizing HIV risk from unfamiliar clients, a willingness to adhere to daily PreP use, and not being concerned about discrimination by others. The main reason for rejecting PrEP or participating in a clinical trial was the concern about the side effects of PrEP.
Acceptability of PrEP among Guangxi FSWs is relatively high, indicating that PrEP intervention programs may be feasible for Chinese FSWs. Given the fact that most of the participants had never heard of PrEP before, and that family, gatekeepers, and social discrimination could significantly affect its acceptability, a comprehensive mix of multiple interventions is necessary for the successful implementation of a PrEP program among this population in Guangxi.
PMCID: PMC3899205  PMID: 24465956
17.  Molecular characterisation of murine acute myeloid leukaemia induced by 56Fe ion and 137Cs gamma ray irradiation 
Mutagenesis  2012;28(1):71-79.
Exposure to sparsely ionising gamma- or X-ray irradiation is known to increase the risk of leukaemia in humans. However, heavy ion radiotherapy and extended space exploration will expose humans to densely ionising high linear energy transfer (LET) radiation for which there is currently no understanding of leukaemia risk. Murine models have implicated chromosomal deletion that includes the hematopoietic transcription factor gene, PU.1 (Sfpi1), and point mutation of the second PU.1 allele as the primary cause of low-LET radiation-induced murine acute myeloid leukaemia (rAML). Using array comparative genomic hybridisation, fluorescence in situ hybridisation and high resolution melt analysis, we have confirmed that biallelic PU.1 mutations are common in low-LET rAML, occurring in 88% of samples. Biallelic PU.1 mutations were also detected in the majority of high-LET rAML samples. Microsatellite instability was identified in 42% of all rAML samples, and 89% of samples carried increased microsatellite mutant frequencies at the single-cell level, indicative of ongoing instability. Instability was also observed cytogenetically as a 2-fold increase in chromatid-type aberrations. These data highlight the similarities in molecular characteristics of high-LET and low-LET rAML and confirm the presence of ongoing chromosomal and microsatellite instability in murine rAML.
PMCID: PMC3716295  PMID: 22987027
18.  TFIIB Co-Localizes and Interacts with α-Tubulin during Oocyte Meiosis in the Mouse and Depletion of TFIIB Causes Arrest of Subsequent Embryo Development 
PLoS ONE  2013;8(11):e80039.
TFIIB (transcription factor IIB) is a transcription factor that provides a bridge between promoter-bound TFIID and RNA polymerase II, and it is a target of various transcriptional activator proteins that stimulate the pre-initiation complex assembly. The localization and/or attachment matrix of TFIIB in the cytoplast is not well understood. This study focuses on the function of TFIIB and its interrelationship with α-tubulins in a mouse model. During oocyte maturation TFIIB distributes throughout the entire nucleus of the germinal vesicle (GV). After progression to GV breakdown (GVBD), TFIIB and α-tubulin co-localize and accumulate in the vicinity of the condensed chromosomes. During the MII stage, the TFIIB signals are more concentrated at the equatorial plate and the kinetochores. Colcemid treatment of oocytes disrupts the microtubule (MT) system, although the TFIIB signals are still present with the altered MT state. Injection of oocytes with TFIIB antibodies and siRNAs causes abnormal spindle formation and irregular chromosome alignment. These findings suggest that TFIIB dissociates from the condensed chromatids and then tightly binds to microtubules from GVBD to the MII phase. The assembly and disassembly of TFIIB may very well be associated with and driven by microtubules. TFIIB maintains its contact with the α-tubulins and its co-localization forms a unique distribution pattern. Depletion of Tf2b in oocytes results in a significant decrease in TFIIB expression, although polar body extrusion does not appear to be affected. Knockdown of Tf2b dramatically affects subsequent embryo development with more than 85% of the embryos arrested at the 2-cell stage. These arrested embryos still maintain apparently normal morphology for at least 96h without any obvious degeneration. Analysis of the effects of TFIIB in somatic cells by co-transfection of BiFC plasmids pHA-Tf2b and pFlag-Tuba1α further confirms a direct interaction between TFIIB and α-tubulins.
PMCID: PMC3828216  PMID: 24244602
19.  Hilar hematoma after extracorporeal shock wave lithotripsy for pancreatic stones 
PMCID: PMC3896577  PMID: 24498532
extracorporeal shock wave lithotripsy; pancreatic stones; hematoma
20.  Comparison of Three Intervention Models for Promoting Circumcision among Migrant Workers in Western China to Reduce Local Sexual Transmission of HIV 
PLoS ONE  2013;8(9):e76107.
Three models for promoting male circumcision (MC) as a preventative intervention against HIV infection were compared among migrant worker populations in western China.
A cohort study was performed after an initial cross-sectional survey among migrant workers in three provincial level districts with high HIV prevalence in western China. A total of 1,670 HIV seronegative male migrants were cluster-randomized into three intervention models, in which the dissemination of promotional materials and expert- and volunteer-led discussions are conducted in one, two, and three stage interventions. Changes in knowledge of MC, acceptability of MC, MC surgery uptake, and the costs of implementation were analyzed at 6-month and 9-month follow-up visits.
All three models significantly increased the participants’ knowledge about MC. The three-stage model significantly increased the acceptability of MC among participants and led to greatest increase in MC uptake. At the end of follow-up, 9.2% (153/1,670) of participants underwent MC surgery; uptake among the one-, two-, and three-stage models were 4.9%, 9.3%, and 14.6%, respectively. Multivariable Cox regression analysis showed that three-stage model was the most effective method to scale up MC, with RR = 2.0 (95% CI, 1.3-3.1, P=0.002) compared to the on-site session model. The two-stage intervention model showed no significant difference with either the on-site session model (RR=1.5, 95% CI, 0.92-2.4, P=0.12) or three-stage model (P=0.10).
A three-stage intervention with gradual introduction of knowledge led to the significantly increase in MC uptake among migrant workers in western China, and was also the most cost-effective method among the three models.
PMCID: PMC3786908  PMID: 24098770
21.  Systematic Review of Anastomotic Leakage Rate According to an International Grading System Following Anterior Resection for Rectal Cancer 
PLoS ONE  2013;8(9):e75519.
A generally acceptable definition and a severity grading system for anastomotic leakages (ALs) following rectal resection were not available until 2010, when the International Study Group of Rectal Cancer (ISGRC) proposed a definition and a grading system for AL.
A search for published data was performed using the MEDLINE database (2000 to December 5, 2012) to perform a systematic review of the studies that described AL, grade AL according to the grading system, pool data, and determine the average rate of AL for each grade after anterior resection (AR) for rectal cancer.
A total of 930 abstracts were retrieved; 40 articles on AR, 25 articles on low AR (LAR), and 5 articles on ultralow AR (ULAR) were included in the review and analysis. The pooled overall AL rate of AR was 8.58% (2,085/24,288); the rate of the asymptomatic leakage (Grade A) was 2.57%, that of AL that required active intervention without relaparotomy (Grade B) was 2.37%, and that of AL that required relaparotomy (Grade C) was 5.40%. The pooled rate of AL that required relaparotomy was higher in AR (5.40%) than in LAR (4.70%) and in ULAR (1.81%), which could be attributed to the higher rate of protective defunctioning stoma in LAR (40.72%) and ULAR (63.44%) compared with that in AR (30.11%).
The new grading system is simple that the ALs of each grade can be easily extracted from past publications, therefore likely to be accepted and applied in future studies.
PMCID: PMC3783382  PMID: 24086552
22.  Comprehensive screening for PRSS1, SPINK1, CFTR, CTRC and CLDN2 gene mutations in Chinese paediatric patients with idiopathic chronic pancreatitis: a cohort study 
BMJ Open  2013;3(9):e003150.
Genetic alterations may contribute to chronic pancreatitis (CP) in Chinese young patients. This study was designed to investigate mutations of cationic trypsinogen (PRSS1), pancreatic secretory trypsin inhibitor or serine protease inhibitor Kazal type 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsin C (CTRC) and CLDN2 genes and the copy number variations (CNVs) of PRSS1 and asses associations with the development of idiopathic CP (ICP) in Chinese children.
A single center.
75 ICP Chinese children (40 boys and 35 girls).
Primary and secondary outcome measures
Mutations of PRSS1, SPINK1, CFTR, CTRC and CLDN2 genes and CNVs.
7 patients had heterozygous mutations in PRSS1, that is, N29I (n=1), R122H or R122C (n=6). The CNVs of PRSS1 in five patients had abnormal copies (1 copy (n=4), five copies (n=1)). 43 patients had IVS3+2T>C (rs148954387) (10 homozygous and 33 heterozygous) in SPINK1. None of the PRSS1 mutation patients carried a SPINK1 mutation. Frequency of PRSS1 and SPINK1 mutations was 9.3% and 57.3%, respectively, with an overall frequency of 66.6% (50/75). In addition, one patient had a novel deletion of CFTR (GCTTCCTA from c.500 to c.508 leading to the shortened polypeptide molecule via a stop codon). Another patient had a novel missense in CLDN2 exon 2 (c.592A>C mutation). Clinically, patients with SPINK1 mutations had a higher rate of pancreatic duct stones, pancreatic pseudocyst and pancreatic calcification than those without SPINK1 mutations (p<0.05).
SPINK1 mutations were more commonly associated with Chinese children with ICP. SPINK1 IVS3+2T>C mutation may play an important role in the pathogenesis of Chinese paediatric ICP. However, further study is needed to confirm and to investigate the role of these genes in the development of Chinese ICP.
PMCID: PMC3773632  PMID: 24002981
Gastroenterology; Genetics
23.  The Clinical Profile of Merkel Cell Carcinoma in Mainland China 
International journal of dermatology  2012;51(9):1054-1059.
Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy, but little is known about the presence or characteristics of MCC in mainland China. A retrospective chart review was conducted to describe the clinical profile of Merkel cell carcinoma in China.
At 18 cancer or dermatology hospitals in metropolitan centers from the six geographical regions of mainland China, approximately 3,100,000 pathology database and medical records were searched for cases that had a pathological diagnosis of MCC between 1970 and 2009. A case series was compiled from retrospective chart reviews of identified MCC patients.
Eight out of 18 participating hospitals reported at least one record of a patient with a pathological diagnosis of MCC, and a total of 22 cases were identified. The median age of patients was 65.5, and 59% were female. The median time from the appearance of a lesion to the time of biopsy was 6 months, and the most common location of lesions was the head and neck. The most common treatment used was surgery alone.
MCC appears to be uncommon in mainland China. Patients in this series are elderly, often had lesions on the head/neck region, and most commonly received surgery alone as treatment. In contrast with MCC in Western countries, the current series' patients were all of Asian ethnicity, had larger lesions at presentation, and none were documented as having HIV or other forms of immunosuppression.
PMCID: PMC3732818  PMID: 22909358
Merkel cell carcinoma; China; skin cancer; case-series
24.  Progenitor Cell Line (hPheo1) Derived from a Human Pheochromocytoma Tumor 
PLoS ONE  2013;8(6):e65624.
Pheochromocytomas are rare tumors generally arising in the medullary region of the adrenal gland. These tumors release excessive epinephrine and norepinephrine resulting in hypertension and cardiovascular crises for which surgery is the only definitive treatment. Molecular mechanisms that control tumor development and hormone production are poorly understood, and progress has been hampered by the lack of human cellular model systems. To study pheochromocytomas, we developed a stable progenitor pheochromocytoma cell line derived from a primary human tumor.
After IRB approval and written informed consent, human pheochromocytoma tissue was excised, minced, dispersed enzymatically, and cultured in vitro. Primary pheochromocytoma cells were infected with a lentivirus vector carrying the catalytic subunit of human telomerase reverse transcriptase (hTERT). The hTERT immortalized cells (hPheo1) have been passaged >300 population doublings. The resulting cell line was characterized morphologically, biochemically and for expression of neuroendocrine properties. The expression of marker enzymes and proteins was assessed by immunofluorescence staining and immunoblotting. Telomerase activity was determined by using the telomeric repeat amplification protocol (TRAP) assay.
We have established a human pheochromocytoma precursor cell line that expresses the neuroendocrine marker, chromogranin A, when differentiated in the presence of bone morphogenic protein 4 (BMP4), nerve growth factor (NGF), and dexamethasone. Phenylethanolamine N-methyltransferase (PNMT) expression is also detected with this differentiation regimen. CD-56 (also known as NCAM, neural cell adhesion molecule) is expressed in these cells, but CD31 (also known as PECAM-1, a marker of endothelial cells) is negative.
We have maintained hTERT-immortalized progenitor cells derived from a pheochromocytoma (hPheo1) in culture for over 300 population doublings. This progenitor human cell line is normal diploid except for a deletion in the p16 region and has inducible neuroendocrine biomarkers. These cells should be a valuable reagent for studying mechanisms of tumor development and for testing novel therapeutic approaches.
PMCID: PMC3681983  PMID: 23785438
25.  Distinct transcriptome profiles identified in normal human bronchial epithelial cells after exposure to γ-rays and different elemental particles of high Z and energy 
BMC Genomics  2013;14:372.
Ionizing radiation composed of accelerated ions of high atomic number (Z) and energy (HZE) deposits energy and creates damage in cells in a discrete manner as compared to the random deposition of energy and damage seen with low energy radiations such as γ- or x-rays. Such radiations can be highly effective at cell killing, transformation, and oncogenesis, all of which are concerns for the manned space program and for the burgeoning field of HZE particle radiotherapy for cancer. Furthermore, there are differences in the extent to which cells or tissues respond to such exposures that may be unrelated to absorbed dose. Therefore, we asked whether the energy deposition patterns produced by different radiation types would cause different molecular responses. We performed transcriptome profiling using human bronchial epithelial cells (HBECs) after exposure to γ-rays and to two different HZE particles (28Si and 56Fe) with different energy transfer properties to characterize the molecular response to HZE particles and γ-rays as a function of dose, energy deposition pattern, and time post-irradiation.
Clonogenic assay indicated that the relative biological effectiveness (RBE) for 56Fe was 3.91 and for 28Si was 1.38 at 34% cell survival. Unsupervised clustering analysis of gene expression segregated samples according to the radiation species followed by the time after irradiation, whereas dose was not a significant parameter for segregation of radiation response. While a subset of genes associated with p53-signaling, such as CDKN1A, TRIM22 and BTG2 showed very similar responses to all radiation qualities, distinct expression changes were associated with the different radiation species. Gene enrichment analysis categorized the differentially expressed genes into functional groups related to cell death and cell cycle regulation for all radiation types, while gene pathway analysis revealed that the pro-inflammatory Acute Phase Response Signaling was specifically induced after HZE particle irradiation. A 73 gene signature capable of predicting with 96% accuracy the radiation species to which cells were exposed, was developed.
These data suggest that the molecular response to the radiation species used here is a function of the energy deposition characteristics of the radiation species. This novel molecular response to HZE particles may have implications for radiotherapy including particle selection for therapy and risk for second cancers, risk for cancers from diagnostic radiation exposures, as well as NASA’s efforts to develop more accurate lung cancer risk estimates for astronaut safety. Lastly, irrespective of the source of radiation, the gene expression changes observed set the stage for functional studies of initiation or progression of radiation-induced lung carcinogenesis.
PMCID: PMC3680091  PMID: 23724988
Gene expression; HZE particles; Ionizing radiation; Human bronchial epithelial cells

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