GHEP-ISFG collaborative exercise on mixture profiles (GHEP-MIX06). Reporting conclusions: Results and evaluation.

One of the main goals of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the field of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, six exercises have been organized. At the present edition (GHEP-MIX06), with 25 participant laboratories, the exercise main aim was to assess mixture profiles results by issuing a report, from the proposal of a complex mock case. One of the conclusions obtained from this exercise is the increasing tendency of participating laboratories to validate DNA mixture profiles analysis following international recommendations. However, the results have shown some differences among them regarding the edition and also the interpretation of mixture profiles. Besides, although the last revision of ISO/IEC 17025:2017 gives indications of how results should be reported, not all laboratories strictly follow their recommendations. Regarding the statistical aspect, all those laboratories that have performed statistical evaluation of the data have employed the likelihood ratio (LR) as a parameter to evaluate the statistical compatibility. However, LR values obtained show a wide range of variation. This fact could not be attributed to the software employed, since the vast majority of laboratories that performed LR calculation employed the same software (LRmixStudio). Thus, the final allelic composition of the edited mixture profile and the parameters employed in the software could explain this data dispersion. This highlights the need, for each laboratory, to define through internal validations its criteria for editing and interpreting mixtures, and to continuous train in software handling.

GHEP-ISFG collaborative exercise on mixture profiles of autosomal STRs (GHEP-MIX01, GHEP-MIX02 and GHEP-MIX03): results and evaluation.

One of the main objectives of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the area of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, three exercises have been organized (GHEP-MIX01, GHEP-MIX02 and GHEP-MIX03), with 32, 24 and 17 participant laboratories respectively. The exercise aims to give a general vision by addressing, through the proposal of mock cases, aspects related to the edition of mixture profiles and the statistical treatment. The main conclusions obtained from these exercises may be summarized as follows. Firstly, the data show an increased tendency of the laboratories toward validation of DNA mixture profiles analysis following international recommendations (ISO/IEC 17025:2005). Secondly, the majority of discrepancies are mainly encountered in stutters positions (53.4%, 96.0% and 74.9%, respectively for the three editions). On the other hand, the results submitted reveal the importance of performing duplicate analysis by using different kits in order to reduce errors as much as possible. Regarding the statistical aspect (GHEP-MIX02 and 03), all participants employed the likelihood ratio (LR) parameter to evaluate the statistical compatibility and the formulas employed were quite similar. When the hypotheses to evaluate the LR value were locked by the coordinators (GHEP-MIX02) the results revealed a minor number of discrepancies that were mainly due to clerical reasons. However, the GHEP-MIX03 exercise allowed the participants to freely come up with their own hypotheses to calculate the LR value. In this situation the laboratories reported several options to explain the mock cases proposed and therefore significant differences between the final LR values were obtained. Complete information concerning the background of the criminal case is a critical aspect in order to select the adequate hypotheses to calculate the LR value. Although this should be a task for the judicial court to decide, it is important for the expert to account for the different possibilities and scenarios, and also offer this expertise to the judge. In addition, continuing education in the analysis and interpretation of mixture DNA profiles may also be a priority for the vast majority of forensic laboratories.

Signaling and biological effects of glucagon-like peptide 1 on the differentiation of mesenchymal stem cells from human bone marrow.

Glucagon-like peptide 1 (GLP-1) functions as an incretin hormone with antidiabetogenic properties. However, the role of GLP-1 in human bone marrow-derived mesenchymal stem cells (hMSCs), if any, remains unknown. The effects of GLP-1 on hMSCs were tested with regard to cell proliferation, cytoprotection, and cell differentiation into adipocytes. The signaling pathways involved in these processes were also analyzed. Cells were characterized with biochemical and morphological approaches before and after being induced to differentiate into adipocytes. PCNA protein levels were used as a proliferation index, whereas cell apoptosis was studied by deprivation of fetal bovine serum. Isolated hMSCs expressed stem cell markers as well as mRNA and GLP-1 receptor protein. GLP-1 increased the proliferation of hMSCs, which decreased when they were induced to differentiate into adipocytes. This process produced biochemical and morphological changes in cells expressing PPARgamma, C/EBPbeta, AP2, and LPL in a time-dependent pattern. Notably, GLP-1 significantly reduced the expression of PPARgamma, C/EBPbeta, and LPL. These effects were exerted at least through the MEK and PKC signaling pathways. In addition, GLP-1 significantly reduced cell apoptosis. Our data indicate that, in hMSCs, GLP-1 promotes cellular proliferation and cytoprotection and prevents cell differentiation into adipocytes. These latter findings underscore the potential therapeutic role of GLP-1 in preventing the adipocyte hyperplasia associated with obesity and, additionally, could bolster the maintenance of hMSC stores by promoting the proliferation and cytoprotection of undifferentiated hMSC.

Glucokinase and glucokinase regulatory proteins are functionally coexpressed before birth in the rat brain.

Our previous description of functional glucokinase (GK) isoforms and their interactions with glucokinase regulatory protein (GKRP) in adult rat and human brains suggested that both participate in glucose sensing in the central nervous system. To determine whether both proteins are coexpressed and active before birth or during early post-natal life, we characterised these molecules in the brains of foetal and post-natal pup rats. We found GK and GKRP mRNAs that were similar to those previously reported in the adult rat brain. Likewise, GK and GKRP gene expression gave rise to proteins of 52 and 69 kDa, respectively. Immunohistochemistry experiments showed the colocalisation of both GK and GKRP proteins in the same brain cells of 21-day-old rat foetuses. Furthermore, coprecipitation of GK and GKRP in the presence of fructose 6-phosphate suggests interactions between both proteins. The presence of GK phosphorylating activity was detected in different brain areas of 21-day-old foetuses with a contribution to the total glucose-phosphorylating activity of between 17.2 +/- 1.7% and 12.4 +/- 3.7%, with the hypothalamus being the region of maximum activity. The hypothalamic GK activity in 21-day-old foetuses has a high apparent K(m) for glucose and no product inhibition by glucose 6-phosphate. Our findings indicate that both proteins may be functionally active before birth and that they can act within a glucose sensor system involved in controlling food intake.