Rapid detection of grass carp reovirus type 1 using RPA-based test strips combined with CRISPR Cas13a system

IntroductionDue to the existence of grass carp reovirus (GCRV), grass carp hemorrhagic disease occurs frequently, and its high pathogenicity and infectivity are great challenges to the aquaculture industry. As a highly pathogenic pathogen, the outbreak of hemorrhagic disease often causes tremendous economic losses. Therefore, it is important to rapidly and accurately detect GCRV on site to control timely.MethodsIn this study, recombinant enzyme amplification (RPA) combined with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a system was employed to establish a method to detect the vp7 gene of grass carp reovirus type 1. This method can be adopted for judging the results by collecting fluorescence signal, ultraviolet excitation visual fluorescence and test strip.ResultsCombined with the RPA amplification experiment, the detection limit of the RPA-CRISPR method can reach 7.2 × 101 copies/μL of vp7 gene per reaction, and the detection process can be completed within 1 h. In addition, this method had no cross-reaction with the other 11 common aquatic pathogens. Then, the performance of the RPA-CRISPR/Cas13a detection method was evaluated by comparing it with the real-time fluorescence quantitative PCR detection method of clinical samples. The results of RPA-CRISPR/Cas13a detection were shown to be in consistence with the results obtained from the real-time fluorescence quantitative PCR detection. The coincidence rate of this method with 26 GCRV clinical samples was 92.31%.DiscussionIn summary, this method has high sensitivity, specificity and on-site practicability for detecting GCRV type 1, and has great application potential in on-site GCRV monitoring

Association between serum keptin concentrations and insulin resistance: A population-based study from China

BACKGROUND Insulin resistance contributes to the cardio-metabolic risk. The effect of leptin in obese and overweight population on insulin resistance was seldom reported. METHODS A total of 1234 subjects (572 men and 662 women) aged ≥18 y was sampled by the procedure. Adiposity measures included BMI, waist circumference, hip circumference, WHR, upper arm circumference, triceps skinfold and body fat percentage. Serum leptin concentrations were measured by an ELISA method. The homeostasis model (HOMA-IR) was applied to estimate insulin resistance. RESULTS In men, BMI was the variable which was most strongly correlated with leptin, whereas triceps skinfold was most sensitive for women. More importantly, serum leptin levels among insulin resistant subjects were almost double compared to the subjects who had normal insulin sensitivity at the same level of adiposity in both men and women, after controlling for potential confounders. In addition, HOMA-IR increased significantly across leptin quintiles after adjustment for age, BMI, total energy intake, physical activity and smoking status in both men and women (p for trend <0.0001). CONCLUSIONS There was a significant association between HOMA-IR and serum leptin concentrations in Chinese men and women, independently of adiposity levels. This may suggest that serum leptin concentration is an important predictor of insulin resistance and other metabolic risks irrespective of obesity levels. Furthermore, leptin levels may be used to identify the cardio-metabolic risk in obese and overweight population.Hui Zuo, Zumin Shi, Baojun Yuan, Yue Dai, Gaolin Wu, Akhtar Hussai

British Society for Sexual Medicine Guidelines on Adult Testosterone Deficiency, With Statements for UK Practice

BACKGROUND: Testosterone deficiency (TD) is an increasingly common problem with significant health implications, but its diagnosis and management can be challenging. AIM: To review the available literature on TD and provide evidence-based statements for UK clinical practice. METHODS: Evidence was derived from Medline, EMBASE, and Cochrane searches on hypogonadism, testosterone (T) therapy, and cardiovascular safety from May 2005 to May 2015. Further searches continued until May 2017. OUTCOMES: To provide a guideline on diagnosing and managing TD, with levels of evidence and grades of recommendation, based on a critical review of the literature and consensus of the British Society of Sexual Medicine panel. RESULTS: 25 statements are provided, relating to 5 key areas: screening, diagnosis, initiating T therapy, benefits and risks of T therapy, and follow-up. 7 statements are supported by level 1, 8 by level 2, 5 by level 3, and 5 by level 4 evidence. CLINICAL IMPLICATIONS: To help guide UK practitioners on effectively diagnosing and managing primary and age-related TD. STRENGTHS AND LIMITATIONS: A large amount of literature was carefully sourced and reviewed, presenting the best evidence available at the time. However, some statements provided are based on poor-quality evidence. This is a rapidly evolving area of research and recommendations are subject to change. Guidelines can never replace clinical expertise when making treatment decisions for individual patients, but rather help to focus decisions and take personal values and preferences and individual circumstances into account. Many issues remain controversial, but in the meantime, clinicians need to manage patient needs and clinical expectations armed with the best clinical evidence and the multidisciplinary expert opinion available. CONCLUSION: Improving the diagnosis and management of TD in adult men should provide somatic, sexual, and psychological benefits and subsequent improvements in quality of life. Hackett G, Kirby M, Edwards D, et al. British Society for Sexual Medicine Guidelines on Adult Testosterone Deficiency, With Statements for UK Practice. J Sex Med 2017;14:1504-1523

A Validated Age-Related Normative Model for Male Total Testosterone Shows Increasing Variance but No Decline after Age 40 Years

The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a normative model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5-97.5 percentile)] at 15.4 (7.2-31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5-97.5 percentile)] to 13.0 (6.6-25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.Publisher PDFPeer reviewe

Microchip-capillary electrophoresis with two-dimensional separation and isotachophoresis preconcentration for determining low abundanceproteins in human urine and dairy products

published_or_final_versionChemistryDoctoralDoctor of Philosoph

Experiment&mdash;Simulation Comparison in Liquid Filling Process Driven by Capillarity

This paper studies modifications made to the Bosanquet equation in order to fit the experimental observations of the liquid filling process in circular tubes that occurs by capillary force. It is reported that there is a significant difference between experimental observations and the results predicted by the Bosanquet equation; hence, it is reasonable to investigate these differences intensively. Here, we modified the Bosanquet equation such that it could consider more factors that contribute to the filling process. First, we introduced the air flowing out of the tube as the liquid inflow. Next, we considered the increase in hydraulic resistance due to the surface roughness of the inner tube. Finally, we further considered the advancing contact angle, which varies during the filling process. When these three factors were included, the modified Bosanquet equation was well correlated with the experimental results, and the R square&mdash;which indicates the fitting quality between the simulation and the experiment&mdash;significantly increased to above 0.99

Magnetic Janus Particles Synthesized by Droplet Micro-magnetofluidic Techniques for Protein Detection

Magnetic droplets on a microfluidic platform can acts as micro-robots, providing wireless, remote, and programmable control. This field of droplet micro-magnetofluidics (DMMF) is useful for droplet merging, mixing and synthesis of Janus structures. Specifically, magnetic Janus particles (MJP) are useful for protein and DNA detection as well as magnetically controlled bioprinting. However, synthesis of MJP with control of the functional phases is a challenge. Hence, we developed a high flow rate, surfactant-free, wash-less method to synthesize MJP by integration of DMMF with hybrid magnetic fields. The effect of flow rate, flow rate ratio, and the hybrid magnetic field on the magnetic component of the Janus droplets and the MJP was investigated. It was found that the magnetization, particle size, and phase distribution inside MJP could be readily tuned by the flow rates and the magnetic field. The magnetic component in the MJP could be concentrated after mixing at flow rate ratio values less than 7.5 and flow rates less than 3 ml/h. The experimental results and our simulations are in good agreement. The synthesized magnetic-fluorescent Janus particles were used for protein detection, with BSA as a model protein.Accepted versio

Chloroplast genome of Gaura parviflora Douglas and its comparative analysis

Gaura parviflora Douglas (Onagraceae) is an annual or perennial herbaceous plant from the prairie of North America. It has become a harmful exotic invading plant in China due to its strong adaptability, fast growth, massive propagation and reproduction. The complete chloroplast (cp) genome of G. parviflora was reported in this study. The size of the complete cp genome of G. parviflora is 161,318 bp in length, including a pair of inverted repeat (IR) regions of 27,402 bp, a large single-copy (LSC) region of 89,132 bp, and a small single-copy (SSC) region of 17,382 bp. A total of 130 genes were annotated, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Comparison of cp genomes of four species from Onagraceae indicated that Onagraceae cp genomes had high nucleotide diversity. In addition, a few highly variable regions of these cp genomes were also detected. The phylogenetic tree showed that G. parviflora is closely related to Oenothera. Thus, the chloroplast genome of G. parviflora can provide valuable genetic information for species identification and phylogenetic analysis