Harmonization and standardization of nucleus pulposus cell extraction and culture methods

BACKGROUND: In vitro studies using nucleus pulposus (NP) cells are commonly used to investigate disc cell biology and pathogenesis, or to aid in the development of new therapies. However, lab-to-lab variability jeopardizes the much-needed progress in the field. Here, an international group of spine scientists collaborated to standardize extraction and expansion techniques for NP cells to reduce variability, improve comparability between labs and improve utilization of funding and resources. METHODS: The most commonly applied methods for NP cell extraction, expansion, and re-differentiation were identified using a questionnaire to research groups worldwide. NP cell extraction methods from rat, rabbit, pig, dog, cow, and human NP tissue were experimentally assessed. Expansion and re-differentiation media and techniques were also investigated. RESULTS: Recommended protocols are provided for extraction, expansion, and re-differentiation of NP cells from common species utilized for NP cell culture. CONCLUSIONS: This international, multilab and multispecies study identified cell extraction methods for greater cell yield and fewer gene expression changes by applying species-specific pronase usage, 60-100 U/ml collagenase for shorter durations. Recommendations for NP cell expansion, passage number, and many factors driving successful cell culture in different species are also addressed to support harmonization, rigor, and cross-lab comparisons on NP cells worldwide

Detection of Porcine Circovirus Type 2 (PCV2) in Mosquitoes from Pig Farms by PCR

To investigate, whether mosquitoes could be potential vectors that maintain or transmit PCV2, 59 mosquito samples were collected from suspicious PCV2-infected pig farms in Hubei and Anhui province, China. Total DNA from these mosquitoes was extracted and then tested for presence of PCV2 nucleic acid by PCR. Four (6.78%) samples showed the positive result. Subsequently, the positive PCR product was cloned into pEASY-T1 vector and sequenced. Sequence analysis displayed that homology between the PCR products and PCV2 strains were more than 94%. These results demonstrate that PCV2 nucleic acid exists in these mosquitoes, which suggests that mosquitoes could serve as mechanical transmission vectors of PCV2

Formal Analysis of Fairness for Optimistic Multiparty Contract Signing Protocol

Optimistic multiparty contract signing (OMPCS) protocols are proposed for exchanging multiparty digital signatures in a contract. Compared with general two-party exchanging protocols, such protocols are more complicated, because the number of protocol messages and states increases considerably when signatories increase. Moreover, fairness property in such protocols requires protection from each signatory rather than from an external hostile agent. It thus presents a challenge for formal verification. In our analysis, we employ and combine the strength of extended modeling language CSP# and linear temporal logic (LTL) to verify the fairness of OMPCS protocols. Furthermore, for solving or mitigating the state space explosion problem, we set a state reduction algorithm which can decrease the redundant states properly and reduce the time and space complexity greatly. Finally, this paper illustrates the feasibility of our approach by analyzing the GM and CKS protocols, and several fairness flaws have been found in certain computation times

IS BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) VAL66MET POLYMORPHISM ASSOCIATED WITH OBSESSIVE-COMPULSIVE DISORDER? A META-ANALYSIS

Background: Brain-derived neurotrophic factor (BDNF) polymorphism plays an important role in neural survival and was proposed to be related to obsessive-compulsive disorder (OCD). Genetic association studies of the BDNF Val66Met polymorphism (rs6265) in OCD have produced inconsistent results. A meta-analysis of studies was conducted to compare the frequency of the BDNF Val66Met variant between cases with OCD and age-matched controls. Subjects and methods: Electronic databases were searched for eligible articles in English and ten studies on the association of the BDNF Val66Met polymorphism with OCD were analysed. Results: A total of ten studies involving 2306 cases with OCD and 4968 healthy controls were included. Findings indicated that the BDNF Val66Met polymorphism was not associated with OCD. But there was a marginally significant effect of the BDNF Val66Met variant on OCD in different ethnicity. Conclusion: Findings from this meta-analytic investigation of published literature provide little support for the Val66Met variant of BDNF as a predictor of OCD. Future well-powered agnostic genome-wide association studies with more refined phenotype are needed to clarify genetic influences on OCD