Seroprevalence and incidence of transfusion-transmitted infectious diseases among blood donors from regional blood transfusion centres in Burkina Faso, West Africa

Background and objective The high prevalence of numerous transfusion‐transmitted infectious diseases such as HIV, HBV, HCV and syphilis in sub‐Saharan Africa affects blood safety for transfusion recipients. The aim of this study was to evaluate the prevalence and incidence of transfusion‐transmissible infectious diseases among blood donors in Burkina Faso. Methods A retrospective study of blood donors’ records from January to December 2009 was conducted. Prevalence and incidence of viral infections were calculated among repeat and first‐time blood donors. Results Of the total of 31 405 first‐time volunteer blood donors in 2009, 24.0% were infected with at least one pathogen and 1.8% had serological evidence of multiple infections. The seroprevalence of HIV, HBV, HCV and syphilis in first‐time volunteer donors was 1.8%, 13.4%, 6.3% and 2.1%, respectively. In 3981 repeat donors, the incidence rate was 3270.2, 5874.1 and 6784.6 per 100 000 donations for anti‐HIV‐1, HBsAg and anti‐HCV, respectively. These numbers varied significantly according to populations where blood is collected and blood centres in Burkina Faso. Conclusion The relatively high prevalence of viral markers in first‐time volunteers and remarkably high incidence of infections in repeat donors raise concerns regarding the safety of these donors and suggest that implementation of NAT might significantly improve the situation.     

Multicenter precision of cortical and trabecular bone quality measures assessed by high‐resolution peripheral quantitative computed tomography

High‐resolution peripheral quantitative computed tomography (HR‐pQCT) has recently been introduced as a clinical research tool for in vivo assessment of bone quality. The utility of this technology to address important skeletal health questions requires translation to standardized multicenter data pools. Our goal was to evaluate the feasibility of pooling data in multicenter HR‐pQCT imaging trials. Reproducibility imaging experiments were performed using structure and composition‐realistic phantoms constructed from cadaveric radii. Single‐center precision was determined by repeat scanning over short‐term (<72 hours), intermediate‐term (3–5 months), and long‐term intervals (28 months). Multicenter precision was determined by imaging the phantoms at nine different HR‐pQCT centers. Least significant change (LSC) and root mean squared coefficient of variation (RMSCV) for each interval and across centers was calculated for bone density, geometry, microstructure, and biomechanical parameters. Single‐center short‐term RMSCVs were <1% for all parameters except cortical thickness (Ct.Th) (1.1%), spatial variability in cortical thickness (Ct.Th.SD) (2.6%), standard deviation of trabecular separation (Tb.Sp.SD) (1.8%), and porosity measures (6% to 8%). Intermediate‐term RMSCVs were generally not statistically different from short‐term values. Long‐term variability was significantly greater for all density measures (0.7% to 2.0%; p < 0.05 versus short‐term) and several structure measures: cortical thickness (Ct.Th) (3.4%; p < 0.01 versus short‐term), cortical porosity (Ct.Po) (15.4%; p < 0.01 versus short‐term), and trabecular thickness (Tb.Th) (2.2%; p < 0.01 versus short‐term). Multicenter RMSCVs were also significantly higher than short‐term values: 2% to 4% for density and micro–finite element analysis (µFE) measures (p < 0.0001), 2.6% to 5.3% for morphometric measures (p < 0.001), whereas Ct.Po was 16.2% (p < 0.001). In the absence of subject motion, multicenter precision errors for HR‐pQCT parameters were generally less than 5%. Phantom‐based multicenter precision was comparable to previously reported in in vivo single‐center precision errors, although this was approximately two to five times worse than ex vivo short‐term precision. The data generated from this study will contribute to the future design and validation of standardized procedures that are broadly translatable to multicenter study designs. © 2013 American Society for Bone and Mineral Research.     

Investigation of the bindings of a class of inhibitors with GSK3β kinase using thermodynamic integration MD simulation and kinase assay

GSK3β kinase is a noteworthy target for discovery of the drugs that will be used to treat several diseases. In the effort to identify a new inhibitor lead compound, we utilized thermodynamic integration (TI)‐molecular dynamics (MD) simulation and kinase assay to investigate the bindings between GSK3β kinase and five compounds that were analogous to a known inhibitor with an available crystal structure. TI‐MD simulations of the first two compounds (analogs 1 and 2 ) were used for calibration. The computed binding affinities of analogs 1 and 2 agreed well with the experimental results. The rest three compounds (analogs 3 – 5 ) were newly obtained from a database search, and their affinity data were newly measured in our labs. TI‐MD simulations predicted the binding modes and the computed ΔΔG values have a reasonably good correlation with the experimental affinity data. These newly identified inhibitors appear to be new leads according to our survey of GSK3β inhibitors listed in recent review articles. The predicted binding modes of these compounds should aid in designing new derivatives of these compounds in the future.     

Large Deformation Mechanisms,Plasticity, and Failure of an Individual Collagen Fibril With Different Mineral Content

Mineralized collagen fibrils are composed of tropocollagen molecules and mineral crystals derived from hydroxyapatite to form a composite material that combines optimal properties of both constituents and exhibits incredible strength and toughness. Their complex hierarchical structure allows collagen fibrils to sustain large deformation without breaking. In this study, we report a mesoscale model of a single mineralized collagen fibril using a bottom‐up approach. By conserving the three‐dimensional structure and the entanglement of the molecules, we were able to construct finite‐size fibril models that allowed us to explore the deformation mechanisms which govern their mechanical behavior under large deformation. We investigated the tensile behavior of a single collagen fibril with various intrafibrillar mineral content and found that a mineralized collagen fibril can present up to five different deformation mechanisms to dissipate energy. These mechanisms include molecular uncoiling, molecular stretching, mineral/collagen sliding, molecular slippage, and crystal dissociation. By multiplying its sources of energy dissipation and deformation mechanisms, a collagen fibril can reach impressive strength and toughness. Adding mineral into the collagen fibril can increase its strength up to 10 times and its toughness up to 35 times. Combining crosslinks with mineral makes the fibril stiffer but more brittle. We also found that a mineralized fibril reaches its maximum toughness to density and strength to density ratios for a mineral density of around 30%. This result, in good agreement with experimental observations, attests that bone tissue is optimized mechanically to remain lightweight but maintain strength and toughness. © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).     

Giant squamous cell carcinoma as a complication of a chronic enterocutaneous fistula: complex parietal reconstruction

Treatment of an enterocutaneous fistula is complex and may require multidisciplinary management, especially when associated with a neoplastic process. Here, we describe the case of a 59‐year‐old patient with a squamous cell carcinoma that had invaded the abdominal wall through a chronic enterocutaneous fistula identified 30 years ago. We combined parietectomy with small intestine and colon resection and inguinal lymphadenectomy in order to obtain clear surgical margins. At the same time, plastic surgery involved the implementation of a large bioprosthesis and coverage with a vastus lateralis muscle free flap.