Characterization of a Family of Scorpion Toxins Modulating Ca2+-Activated Cl- Current in Vascular Myocytes.

The pharmacology of calcium-activated chloride current is not well developed. Peptides from scorpion venom present potent pharmacological actions on ionic conductance used to characterize the function of channels but can also be helpful to develop organic pharmacological tools. Using electrophysiological recording coupled with calcium measurement, we tested the potent effect of peptides extracted from Leuirus quinquestratus quinquestratus venom on the calcium-activated chloride current expressed in smooth muscle cells freshly dissociated from rat portal veins. We identified one peptide which selectively inhibited the chloride conductance without effects on either calcium signaling or calcium and potassium currents expressed in this cell type. The synthetic peptide had the same affinity, but the chemical modification of the amino acid sequence altered the efficiency to inhibit the calcium-activated chloride conductance.

Data integrity in regulated bioanalysis: a summary from the European Bioanalysis Forum Workshop in collaboration with the MHRA.

In this conference report, we summarize the main findings and messages from a workshop on 'Data Integrity'. The workshop was held at the 11th European Bioanalysis Forum Open (EBF) Symposium in Barcelona (21-23 November 2018), in collaboration with the Medicines and Health products Regulatory Agency to provide insight and understanding of regulatory data integrity expectations. The workshop highlighted the importance of engaging with software developers to address the gap between industry's data integrity needs and current system software capabilities. Delegates were also made aware of the importance of implementing additional procedural controls to mitigate the risk associated with using systems that do not fully meet data integrity requirements.

Feedback from a European Bioanalysis Forum survey on bioanalysis of drugs in tissues.

Tissue analysis has always been a difficult discipline of bioanalysis. Laboratories that perform bioanalysis in tissue are facing a lot of challenges and questions before starting experiments, from a scientific/technical point of view regarding more regulated aspects. Actually, literature is poor regarding the more technical and scientific aspects but also beyond that no clear guidance is available on this topic and laboratories performing tissue analysis face real ambiguity regarding regulatory requirements, always with the risk of under- or over-validation of the assay. For all of these reasons bioanalysis in tissue became a frequently discussed topic within the European Bioanalytical Forum (EBF) organization. The EBF then decided to treat this as a specific topic, and carried out a survey that was done in two steps between 2012 and 2013. This paper represents an exhaustive summary of the result of this survey that includes themost important aspects of tissue bioanalysis. This survey provided the team a good starting point for their discussions and resulted in an EBF recommendation paper published separately.

Recommendations from the European Bioanalysis Forum on method establishment for tissue homogenates.

Tissue analysis has always been a difficult discipline of bioanalysis. Differences in scientific approaches or level of adherence to regulated guidelines have led to a growing ambiguity on how to perform tissue analysis, an ambiguity that starts with the question of if we analyze tissue or tissue homogenates. The European Bioanalysis Forum (EBF) is proposing a recommendation on how to perform method establishment and analysis of tissue homogenates. The recommendation is based on broad discussions and survey data from the EBF community and, as for many EBF recommendations, focuses on finding the right balance between science, technology and regulations.

Evaluation of the relative performance of 12 urinary biomarkers for renal safety across 22 rat sensitivity and specificity studies.

Novel urinary kidney safety biomarkers have been identified recently that may outperform or add value to the conventional renal function biomarkers, blood urea nitrogen (BUN) and serum creatinine (SCr). To assess the relative performance of the growing list of novel biomarkers, a comprehensive evaluation was conducted for 12 urinary biomarkers in 22 rat studies including 12 kidney toxicants and 10 compounds with toxicities observed in organs other than kidney. The kidney toxicity studies included kidney tubular toxicants and glomerular toxicants. The 12 urinary biomarkers evaluated included Kim-1, clusterin, osteopontin, osteoactivin, albumin, lipocalin-2, GST-α, ß2-microglobulin, cystatin C, retinol binding protein 4, total protein, and N-acetyl-ß-D-glucosaminidase. Receiver operator characteristic (ROC) curves were generated for each biomarker and for BUN and SCr to compare the relative performance of the 12 biomarkers in individual animals against the microscopic histomorphologic changes observed in the kidney. Among the kidney toxicity biomarkers analyzed, Kim-1, clusterin, and albumin showed the highest overall performance for detecting drug-induced renal tubular injury in the rat in a sensitive and specific manner, whereas albumin showed the highest performance in detecting drug-induced glomerular injury. Although most of the evaluated kidney biomarkers were more sensitive in detecting kidney toxicity compared with BUN and SCr, all biomarkers demonstrated some lack of specificity, most notably NGAL and osteopontin, illustrating the need for caution when interpreting urinary biomarker increases in rat samples when organ toxicity is unknown.