1,720,967 research outputs found
Investigation on the application of DNA forensic human identification techniques to detect homologous blood transfusions in doping control
No full textHomologous blood transfusion is an illicit practice used by athletes to improve the delivery of oxygen to tissues and, as such, it is banned in sports. The current method of detection is based on the flow cytofluorimetric phenotypic identification of red blood cells mismatch of minor blood group antigens between the donor and the recipient. The selectivity of this method to clearly identify transfused samples is related to the number of blood group antigens tested. Despite the fact that several different antigens are investigated, two individuals sharing the expression of the same minor blood group antigens pattern cannot be distinguished. We tested the possibility to use a different approach based on DNA forensic human identification techniques. Analysis of the DNA short tandem repeats (STRs) demonstrated its suitability in detecting mixed whole blood samples simulating homologous blood transfusion in 100% of the samples tested, ensuring the capability of clearly detecting mixed blood cell populations also on samples where the fraction of the minoritary population is as low as 2.5%. (C) 2013 Elsevier B.V. All rights reserved
Satisfactory performance of hepatocytes in three-dimensional culture on innovative biopolymeric scaffolds.
No full textHuman hepatocytes in three-dimensional culture on innovative biopolymeric scaffolds as a useful system for in vitro toxicology tests.
No full textA three-dimension hepatocyte-alginate culture system as a tool for in vitro pharmacological tests.
No full textThe approach of microRNA expression analysis in the detection of autologous blood transfusion in doping control
No full textBlood transfusion (BT) as blood doping practice is banned by the World Anti-Doping Agency (WADA) and can be abused by cheating athletes to increase the rate of oxygen transport to tissues with the aim to improve sport performance. At present, a method for the detection of Homologous Blood Transfusion (HBT) has been implemented by the WADA accredited antidoping laboratories worldwide, while no internationally recognized method has been finalized so far for the direct detection of autologous blood transfusions (ABT), which can at present be only detected indirectly by targeting longitudinal profiling of key hematological parameters. In this perspective, several researches approaching different fields are underway to find reliable biomarkers to be suitable in the development of a method to directly detect autologous blood transfusion
Application of DNA-based forensic analysis for the detection of homologous transfusion of whole blood and of red blood cell concentrates in doping control
No full textIn this work we present the application of a method for the identification of homologous blood transfusions using forensic genetic techniques based on DNA typing. Ex vivo mixtures of human blood samples - either whole blood or red blood cell concentrates - simulating homologous blood transfusions at different percentages of the donor were typed for a panel of 16 highly variable DNA short tandem repeats (STR). Tested samples included also mixtures, which gave false-negative results if assayed by the reference flow cytofluorimetric method, which is based on the recognition of target antigens located on the membrane of the red blood cell. The recognition of triplets and quadruplets at various loci gave information of the presence of cells belonging to different individuals, as it is the case for homologous blood transfusions. Specificity and sensitivity of the method were assessed in the validation study. The method proved to be unequivocally specific since it was able to recognize all single profiles of each individual, clearly discriminating them from mixtures. Sensitivity resulted as a consequence of the percentage of the donor aliquot in the total volume of the mixture. Although the source of DNA in a blood sample is represented only by nucleated white blood cells, the same procedure resulted effective also in detecting mixtures of red blood cell concentrates (RBCC) from leukodepletion procedure: DNA of the donor from the residual white blood cells resulted still detectable, even if with an expected loss of sensitivity. The proposed approach may contribute to reduce the risk of false-negative results, which may occur using the reference cytofluorimetric method
Dielectric characterization of hepatocytes in suspension and embedded into two different polymeric scaffolds
No full textThe dielectric and conductometric properties of hepatocytes in two different environments (in aqueous suspension and embedded into polymeric scaffolds) have been investigated in the frequency range from 1 kHz to 2 GHz, where the interfacial electrical polarization gives rise to marked dielectric relaxation effects. We analyzed the dielectric behavior of hepatocytes in complete medium aqueous suspensions in the light of effective medium approximation for heterogeneous systems and hepatocytes cultured into two different highly porous and interconnected polymeric structures. In the former case, we have evaluated the passive electrical parameters associated with both the plasmatic and nuclear membrane, finding a general agreement with the values reported elsewhere, based on a partially different analysis of the experimental spectra. In the latter case, we have evaluated the cell growth into two different polymeric scaffolds made of alginate and gelatin with a similar pore distribution and similar inter-connectivity. Based on a qualitative analysis of the dielectric spectra, we were able to provide evidence that alginate scaffolds allow an overall survival of cells better than gelatin scaffold can do. These indications, confirmed by biological tests on cell viability, suggest that hepatocytes embedded in alginate scaffolds are able to perform liver specific functions even over on extended period of time. (c) 2012 Elsevier B.V. All rights reserved
Searching for markers to detect autologous blood transfusion. An investigation on platelets activation by flow cytofluorimetry.
No full textBlood transfusion (BT) are banned by the WADA and are abused by cheating athletes to improve tissues oxygenation. At present, only a method to detect homologous blood transfusion (HBT) by flow cytofluorimetry, based on the detection of different populations of minor red blood cells surface antigens, is available. [1]
For autologous blood transfusion (ABT), several attempts have been made in the research of reliable markers to be applied for the abuse detection. These markers are of multiple origin and include gene expression of erythropoiesis, hematological indexes, total hemoglobin mass, markers of storage of red blood cells and phthalates residues from blood bags. A recent paper by Silvain et al. 2010 [2] claimed that red blood cell transfusion increases platelet activation in healthy volunteers, so opening the possibility to use platelet activation as indirect marker for the detection of blood transfusion abus
Rapid Prototyping of Chitosan-Coated Alginate Scaffolds Through the Use of a 3D Fiber Deposition Technique
No full textThree dimensional, periodic scaffolds of chitosan-coated alginate are fabricated in a layer-by-layer fashion by rapid prototyping. A novel dispensing system based on two coaxial needles deliver simultaneously an alginate and calcium chloride solutions permitting the direct deposition of alginate fibers according to any designed pattern. Coating of the alginate fiber with chitosan and subsequent cross-linking with EDC and genipin assured the endurance of the scaffold in culture environment for a prolonged period of time. The cross-linking protocol adopted, imparted to the scaffold a hierarchical chemical structure as evidenced by Confocal Laser Microscopy and FTIR spectroscopy. The core of the fibers making up the scaffold is represented by alginate chains cross-linked by ester bonds only, the periphery of the fiber are constituted by an inter-polyelectrolyte complex of alginate and chitosan cross-linked in all pair combinations. Fibers belonging to adjacent layers are glued together by the chitosan coating. Mechanical behavior of the scaffolds characterized by different layouts of deposition was determined revealing anisotropic properties. The biocompatibility and capability of the scaffolds to sustain hepatocytes (HepaRG) cultures was demonstrated. Typical hepatic function such as albumin and urea secretion and induction of CYP3A4 enzyme activity following drug administration were excellent, thus proving the potentials of these constructs in monitoring liver specific function
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