In this study, a total of 248 ground beef samples were analyzed for the presence of Shiga toxin-producing Escherichia coli (STEC). Out of these samples, only one (0.4%) tested positive for STEC.
View Article and Find Full Text PDFIntroduction: Pharmacokinetic/pharmacodynamic modelling has emerged as a valuable technique for understanding drug exposure and response relationships in drug development. Pharmacokinetic data are often obtained by taking multiple blood samples, which may disturb physiological parameters and complicate study designs. Wearable automatic blood sampling systems can improve this limitation by collecting dried blood samples at programmable time points without disrupting cardiovascular parameters.
View Article and Find Full Text PDFConducting safety evaluations of new drugs using conscious animals has been a specialty of our working group for thirty years. In this article, we review the various technical challenges and solutions dealt with over the years to improve both the data quality and the well being of our animal subjects. Of particular interest for us has been the use of telemetry-based data acquisition for conducting studies on cardiovascular (CV) function.
View Article and Find Full Text PDFIntroduction: A safety pharmacology study detects and evaluates potential side effects of a new drug on physiological function at therapeutic levels and above and, in most cases, prior to the initiation of clinical trials. The aim of this study was to investigate the effects of environmental and biological factors on resting heart rate (HR), a representative cardiac parameter in cardiovascular safety pharmacology.
Methods: Over twenty years, 143 dogs (Beagles, Labradors and mongrels) received implanted telemetry transmitters to measure aortic pressure (AP), left ventricular pressure (LVP), Electrocardiogram (ECG) and body temperature.
Rural residents are more likely to be physically inactive than their urban counterparts and are therefore at higher risk for obesity and cardiovascular disease. Research has shown that these disparities are driven in part by the physical environment, policies, and programming in rural communities. The purpose of this study was to use the Rural Active Living Assessment (RALA) to assess the physical activity environment of four Midwestern towns and to develop physical activity maps to support Enhanced Win With Wellness, a community-based cardiovascular risk reduction program.
View Article and Find Full Text PDFHemolytic Uremic Syndrome (HUS) associated with Shiga-toxigenic (STEC) infections is the principal cause of acute renal injury in pediatric age groups. Shiga toxin type 2 (Stx2) has in vitro cytotoxic effects on kidney cells, including human glomerular endothelial (HGEC) and Vero cells. Neither a licensed vaccine nor effective therapy for HUS is available for humans.
View Article and Find Full Text PDFTo navigate the social world, humans heavily rely on gaze for non-verbal communication as it conveys information in a highly dynamic and complex, yet concise manner: For instance, humans utilize gaze effortlessly to direct and infer the attention of a possible interaction partner. Many traditional paradigms in social gaze research though rely on static ways of assessing gaze interaction, e.g.
View Article and Find Full Text PDFDefining an appropriate and efficient assessment of drug-induced corrected QT interval (QTc) prolongation (a surrogate marker of torsades de pointes arrhythmia) remains a concern of drug developers and regulators worldwide. In use for over 15 years, the nonclinical International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) S7B and clinical ICH E14 guidances describe three core assays (S7B: in vitro hERG current & in vivo QTc studies; E14: thorough QT study) that are used to assess the potential of drugs to cause delayed ventricular repolarization. Incorporating these assays during nonclinical or human testing of novel compounds has led to a low prevalence of QTc-prolonging drugs in clinical trials and no new drugs having been removed from the marketplace due to unexpected QTc prolongation.
View Article and Find Full Text PDFIntroduction: Alterations in cardiac contractility can have significant clinical implications, highlighting the need for early detection of potential liabilities. Pre-clinical methods to assess contractility are typically invasive and their translation to human measures of cardiac function are not well defined. Clinically, cardiac function is most often measured non-invasively using echocardiography.
View Article and Find Full Text PDFJ Pharmacol Toxicol Methods
September 2020
The latex agglutination test using single-chain antibody fragments (scFvStx1 and scFvStx2) coupled to latex particles, was compared with the gold standard Vero cell assay for Shiga toxin (Stx) detection, aiming to estimate the diagnosis potential of these scFv fragments in a rapid and straightforward test. The latex complexes identified the presence of the toxins up to a 1:8 dilution in the majority of the evaluated strains. Moreover, the Stx concentration was indirectly determined in Stx-producing Escherichia coli (STEC) strains, allowing detection limit inference.
View Article and Find Full Text PDFMicroorganisms
October 2019
A recent article by Castro et al. describes a systematic review of Shiga-toxin producing (STEC) in Brazil. [.
View Article and Find Full Text PDFContractility of the myocardium engines the pumping function of the heart and is enabled by the collective contractile activity of its muscle cells: cardiomyocytes. The effects of drugs on the contractility of human cardiomyocytes can provide mechanistic insight that can support the prediction of clinical cardiac drug effects early in drug development. Cardiomyocytes differentiated from human-induced pluripotent stem cells have high potential for overcoming the current limitations of contractility assays because they attach easily to extracellular materials and last long in culture, while having human- and patient-specific properties.
View Article and Find Full Text PDFWe compared a published computational model of the action potential of a specific type of human induced pluripotent stem cell -derived cardiomyocytes (hiPSC-CM) with experimental field potential data with regard to their inter-beat interval and the duration of repolarization. In particular, concomitant changes in inter-beat interval and duration of repolarization were calculated after reduction and/or augmentation of specific ion channel conductances as a surrogate for pharmacological manipulation. The observed mismatches between calculations and experimental data indicate that there is information missing about the cellular test system.
View Article and Find Full Text PDFDrug-induced effects on cardiac contractility can be assessed through the measurement of the maximal rate of pressure increase in the left ventricle (LVdP/dt) in conscious animals, and such studies are often conducted at the late stage of preclinical drug development. Detection of such effects earlier in drug research using simpler, test systems would be a valuable addition to our strategies for identifying the best possible drug development candidates. Thus, testing platforms with reasonably high throughput, and affordable costs would be helpful for early screening purposes.
View Article and Find Full Text PDFShiga toxin (Stx)-producing (STEC) and its subgroup enterohemorrhagic are important pathogens involved in diarrhea, which may be complicated by hemorrhagic colitis and hemolytic uremic syndrome, the leading cause of acute renal failure in children. Early diagnosis is essential for clinical management, as an antibiotic treatment in STEC infections is not recommended. Previously obtained antibodies against Stx and Stx toxins were employed to evaluate the sensitivity and specificity of the latex Agglutination test (LAT), lateral flow assay (LFA), and capture ELISA (cEIA) for STEC detection.
View Article and Find Full Text PDFShiga toxin-producing (STEC) O113:H21 strains are associated with human diarrhea and some strains may cause hemolytic-uremic syndrome (HUS). In Brazil, these strains are commonly found in cattle but, so far, were not isolated from HUS patients. Here, a system biology approach was used to investigate the differential transcriptomic and phenotypic responses of enterocyte-like Caco-2 cells to two STEC O113:H21 strains with similar virulence factor profiles (i.
View Article and Find Full Text PDFJ Pharmacol Toxicol Methods
January 2020
This meeting report is based on presentations given at the first Drug Safety Africa Meeting in Potchefstroom, South Africa from November 20-22, 2018 at the North-West University campus. There were 134 attendees (including 26 speakers and 34 students) from the pharmaceutical industry, academia, regulatory agencies as well as 6 exhibitors. These meeting proceedings are designed to inform the content that was presented in terms of Safety Pharmacology (SP) and Toxicology methods and models that are used by the pharmaceutical industry to characterize the safety profile of novel small chemical or biological molecules.
View Article and Find Full Text PDFExotic psittacine birds have been implicated as reservoir of diarrheagenic (), including enteropathogenic (EPEC) and Shiga-toxin producing (STEC). Here, we present a genotypic and phenotypic characterization of typical EPEC/STEC hybrid strains isolated from exotic psittacine birds. The strains were positive for , A, and s2f genes, belong to serotype O137:H6 and ST2678.
View Article and Find Full Text PDFDiarrhoeagenic Escherichia coli (DEC) is a leading cause of infectious diarrhoea worldwide. In recent years, Escherichia albertii has also been implicated as a cause of human enteric diseases. This study describes the occurrence of E.
View Article and Find Full Text PDFJ Pharmacol Toxicol Methods
January 2019
Southern Africa (South Africa as well as neighboring countries) has not had an infrastructure for testing the safety of new drugs or other therapeutic entities, including plant-based or herbal treatments coming from the indigenous cultures, according to the current practice and regulatory requirements. Simultaneously, Southern Africa is challenged by very high rates of immune deficiency diseases which have further led to the resurgence of diseases such as tuberculosis, which is commonly thought to be eradicated, at least in Western cultures. Thus, there is high medical need for affordable, effective and safe treatments, but up to now there has been no local expertise and capabilities for state-of-the-art drug testing.
View Article and Find Full Text PDFIntroduction: A newly developed total implant telemetry system for cardiovascular (CV), electrophysiological and body temperature measurement was evaluated. A cloud-based transmission of the physiological signals allowed an assessment of the quality of the physiological signals despite the physical separation between the instrumented animals and the evaluating home laboratory. The new system is intended to be used for safety pharmacological evaluations of drug candidates in various species.
View Article and Find Full Text PDFIntroduction: The sensitivity of a given test to detect a treatment-induced effect in a variable of interest is intrinsically related to the variability of that variable observed without treatment and the number of observations made in the study (i.e. number of animals).
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