Highly sensitive near-simultaneous assay of multiple "lean meat agent" residues in swine urine using a disposable electrochemiluminescent immunosensors array

Nowadays, β(2)-agonists are abused illegally as "lean meat agents" for food-producing animals, and cause increasing food-safety accidents in some countries. Due to their hazard to the human health, "lean meat agents" are banned in most countries and required to be routinely monitored. We herein report a disposable electrochemiluminescent immunosensors array for near-simultaneous assay of multiple β(2)-agonist residues in swine urine, by using ractopamine and salbutamol as the models. In this investigation, a screen-printed carbon electrodes array was assembled and acted as the substrate of the immunosensors array. Then the immunosensors array was constructed by site-selectively immobilizing the antigens of ractopamine and salbutamol on the working electrodes of array. After the competitive immuno-binding, with the aid of a homemade single-pore-four-throw switch, the electrochemiluminescent signals of the two β(2)-agonists were sequentially detected using a non-array detector. The limits of detection for ractopamine and salbutamol were 8.5 and 17pg/mL, respectively, which were much lower than those of the most previous reports. Compared with other routine methods based on chromatography and ELISA, this method is more suitable for screening of multiple β(2)-agonists in quantities of samples, owing to its merits of low cost, user-friendliness and high throughput, and shows great promise in food safety and agonist surveillance.     

人脐带和骨髓间充质干细胞体外分离培养及生物学特性比较

目的体外分离培养、扩增人脐带间充质干细胞(h UC-MSC)和人骨髓间充质干细胞(h BM-MSC),并对其生物学特性进行比较。方法采用组织块贴壁法从足月胎儿脐带分离、纯化和培养h UC-MSC,健康成人骨髓肝素抗凝后,采用密度梯度离心法分离、纯化和培养h BM-MSC;用倒置显微镜观察两种细胞的形态及细胞生长增殖情况,流式细胞仪分析检测第3代细胞表面标志的表达,Von?Kossa染色及油红O染色检测分化潜能。结果镜下两种细胞均为贴壁生长,形态为均一的成纤维细胞样,取相同数量的细胞传代接种后,h UC-MSC的增殖速率快于h BM-MSC,两种细胞具有均一的细胞表型,均表达CD29、CD44、CD105,不表达CD45、CD34、HLA-DR、HLA-G、CD80、CD86,两种细胞都有成骨、成脂分化潜能,但h UC-MSC的分化潜能更强。结论 h UC-MSC与h BM-MSC具有相似的生物学特性,且前者具有更强的增殖能力和分化潜能,h UC-MSC有望成为h BMMSC理想的替代来源。     

Integrin-associated molecules and signalling cross talking in osteoclast cytoskeleton regulation

In the ageing skeleton, the balance of bone reconstruction could commonly be broken by the increasing of bone resorption and decreasing of bone formation. Consequently, the bone resorption gradually occupies a dominant status. During this imbalance process, osteoclast is unique cell linage act the bone resorptive biological activity, which is a highly differentiated ultimate cell derived from monocyte/macrophage. The erosive function of osteoclasts is that they have to adhere the bone matrix and migrate along it, in which adhesive cytoskeleton recombination of osteoclast is essential. In that, the podosome is a membrane binding microdomain organelle, based on dynamic actin, which forms a cytoskeleton superstructure connected with the plasma membrane. Otherwise, as the main adhesive protein, integrin regulates the formation of podosome and cytoskeleton, which collaborates with the various molecules including: c-Cbl, p130^Cas, c-Src and Pyk2, through several signalling cascades cross talking, including: M-CSF and RANKL. In our current study, we discuss the role of integrin and associated molecules in osteoclastogenesis cytoskeletal, especially podosomes, regulation and relevant signalling cascades cross talking.     

侧脑室注射促甲状腺激素释放激素对大鼠睡眠—觉醒的影响

采用多导睡眠描记术研究了例脑室注射促甲状腺激素释放激素(TRH)对正常大鼠和去甲状腺大鼠睡眠-觉醒的影响。在正常大鼠,TRH引起觉醒增加,浅慢波睡眠(SWS_1)、深慢波睡眠(SWS_2)和总睡眠时间(TST)均减少,异相睡眠(PS)消失,SWS_1、SWS_2和PS的潜伏期均显著延长,给药后立即产生效应并在1h内达高峰。去甲状腺对大鼠的睡眠-觉醒无明显影响,注射TRH后引起的效应与正常大鼠相似。结果提示TRH有促进大鼠觉醒的作用,对各睡眠时相均有抑制作用,其作用部位可能在下丘脑以外的中枢结构。     

Polymorphisms of the DNA Methyltransferase 1 Associated with Reduced Risks of Helicobacter pylori Infection and Increased Risks of Gastric Atrophy

Introduction

DNA methyltransferase-1(DNMT1) is an important enzyme in determining genomic methylation patterns in mammalian cells. We investigated the associations between SNPs in the DNMT1 gene and risks of developing H. pylori seropositivity, gastric atrophy and gastric cancer in the Chinese population.

Methods

The study consisted of 447 patients with gastric cancer; 111 patients with gastric atrophy; and 961 healthy controls. Five SNPs, rs10420321, rs16999593, rs8101866, rs8111085 and rs2288349 of the DNMT1 gene were genotyped. Anti-H.pylori IgG was detected by ELISA. Gastric atrophy was screened by the level of serum pepsinogen Ιand II and then confirmed by endoscopy and histopatholgical examinations.

Results

The age- and sex-adjusted OR of H. pylori seropositivity was 0.67 (95%CI: 0.51–0.87) for rs8111085 TC/CC genotypes, significantly lower than the TT genotype in healthy controls. The adjusted OR of H.pylori seropositivity was 0.68 (95%CI: 0.52–0.89) for rs10420321 AG/GG genotypes. In addition, patients carrying rs2228349 AA genotype have a significantly increased risk for H.pylori seropositivity (OR = 1.67; 95%CI: 1.02–2.75). Further haplotype analyses also showed that the ATTTG and ATCTA are significantly associated with increased risks in H.pylori infection compared to the GTCCG haplotype (OR = 1.38, 95%CI: 1.08–1.77; OR = 1.40, 95% CI: 1.09–1.80). The adjusted ORs of gastric atrophy were 1.66 (95%CI: 1.06–2.61) for rs10420321 GG genotype, and 1.67 (95%CI 1.06–2.63, P = 0.03) for rs8111085 CC genotype, but no association was found between SNPs in the DNMT1 gene and risk of developing gastric cancer.

Conclusions

Individuals with rs10420321 GG and rs8111085 CC genotype of the DNMT1 gene were associated with reduced risks for H.pylori infection. On the other hand, higher risks of gastric atrophy were found in the carriers with these two genotypes compared to other genotypes. Our results suggested that SNPs of DNMT1 could be used as genotypic markers for predicting genetic susceptibilities to H.pylori infection and risks in gastric atrophy.     

Advantages and Challenges of A Village Doctor-Based Cognitive Behavioral Therapy for Late-Life Depression in Rural China: A Qualitative Study

Background

The delivery of mental health services in rural China has been notably limited due to lack of qualified mental health professionals among other impeding factors. A village doctor-based cognitive behavioral therapy intervention may be one way of improving accessibility. The purpose of this study was to explore the advantages and challenges of implementing this intervention, as delivered by trained village doctors, to treat late-life depression in rural China.

Methods

We conducted one focus group discussion with 10 village doctors, 10 individual interviews with each of the village doctors, and individual interviews with 19 older adults. The topic guides were advantages and challenges of the intervention program from the perspective of the village doctors and older adults. Interviews were audio-recorded, transcribed, coded using NVivo 8, and analyzed using thematic analysis.

Results

The village doctors stressed the importance of role-playing and using instructive manuals in the training. Proper supervision was also a key component of the program. The benefits received from the intervention for the village doctors and the elders were positive such that both the doctors and the older adults were willing to implement/receive this intervention. Cultural and political factors (renqing and perceived policy consideration) facilitated the elders’ access to mental health services. Challenges included a lack of real therapy (in contrast to role-playing) demonstrated in the training and lack of a step-by-step manual based on different types of problems encountered. Other impediments to the successful implementation of the intervention included the time constraints of village doctors and the presence of other people when conducting the intervention.

Conclusions

The present study has demonstrated that the intervention program is likely to be an acceptable geriatric depression intervention in rural China if several challenges are appropriately addressed.     

藏猪小肠形态、消化酶及微生物多样性研究

[目的]肠道是动物的主要消化器官,同时也是机体抵抗外源病原菌的重要屏障,已有研究表明,动物的品种、饲养方式、生长阶段均会影响动物的肠道菌群结构,但对舍饲和放牧饲养条件下藏猪的肠道菌群结构,以及藏猪和长白、约克与杜洛克三元杂交猪(DLY猪)的肠道菌群结构是否有差异,尚未见报道.[方法]本研究选取6-7月龄的放牧藏猪、舍饲...     

Development of a versatile computer integrated control system for bioprocess controls

A general approach is described for the implementation of a networked multi-unit computer integrated control system. The use of data acquisition hardware and graphical programming tools alleviates tedious programming and maintains potency and flexibility. One application of the control system, the control of a mammalian cell perfusion culture based on a key nutrient glucose concentration, was demonstrated. The control system offers customized user interface for all process control parameters and allows the flexibility for continued improvement and implementation of new tailored functions. The temperature, pH, dissolved oxygen and glucose level were accurately controlled. This revised version was published online in June 2006 with corrections to the Cover Date.     

Resonance Rayleigh-scattering method for the determination of proteins with gold nanoparticle probe

Gold nanoparticles with a 12-nm diameter were used as probes for the determination of proteins by resonance Rayleigh-scattering techniques. In weak acidic solution, large amounts of citrate anions will self-assemble on the surface of positively charged gold nanoparticles to form supermolecular compounds with negative charges. Below the isoelectric point, proteins with positive charges such as human serum albumin (HSA), bovine serum albumin (BSA), and ovalbumin (Ova) can bind gold nanoparticles to form larger volume products (the diameter of the binding product of gold nanoparticles with HSA is 23 nm.) through electrostatic force, hydrogen bonds, and hydrophobic effects, which can result in a red shift of the maximum absorption wavelength, the remarkable enhancement of the resonance Rayleigh-scattering intensity (RRS), and the appearance of the RRS spectra. At the same time, the second-order-scattering (SOS) and frequency-doubling-scattering (FDS) intensities are also enhanced. The binding products of gold nanoparticles with different proteins have similar spectral characteristics and the maximum wavelengths are located near 303 nm for RRS, 540 nm for SOS, and 390 for FDS, respectively. The scattering enhancement (DeltaI) is directly proportional to the concentration of proteins. Among them, the RRS method has the highest sensitivity and the detection limits are 0.38 ng/ml for HSA, 0.45 ng/ml for BSA, and 0.56 ng/ml for Ova, separately. The methods have good selectivity. A new RRS method for the determination of trace proteins using a gold nanoparticle probe has been developed. Because gold nanoparticle probes do not need to be modified chemically in advance, the method is very simple and fast.