Modelling the long QT syndrome with induced pluripotent stem cells

The ability to generate patient-specific human induced pluripotent stem cells (iPSCs) offers a new paradigm for modelling human disease and for individualizing drug testing. Congenital long QT syndrome (LQTS) is a familial arrhythmogenic syndrome characterized by abnormal ion channel function and sudden cardiac death. Here we report the development of a patient/disease-specific human iPSC line from a patient with type-2 LQTS (which is due to the A614V missense mutation in the KCNH2 gene). The generated iPSCs were coaxed to differentiate into the cardiac lineage. Detailed whole-cell patch-clamp and extracellular multielectrode recordings revealed significant prolongation of the action-potential duration in LQTS human iPSC-derived cardiomyocytes (the characteristic LQTS phenotype) when compared to healthy control cells. Voltage-clamp studies confirmed that this action-potential-duration prolongation stems from a significant reduction of the cardiac potassium current I(Kr). Importantly, LQTS-derived cells also showed marked arrhythmogenicity, characterized by early-after depolarizations and triggered arrhythmias. We then used the LQTS human iPSC-derived cardiac-tissue model to evaluate the potency of existing and novel pharmacological agents that may either aggravate (potassium-channel blockers) or ameliorate (calcium-channel blockers, K(ATP)-channel openers and late sodium-channel blockers) the disease phenotype. Our study illustrates the ability of human iPSC technology to model the abnormal functional phenotype of an inherited cardiac disorder and to identify potential new therapeutic agents. As such, it represents a promising paradigm to study disease mechanisms, optimize patient care (personalized medicine), and aid in the development of new therapies.     

The gonad stimulating potency of date palm pollen grains

Résumé La principale substance gonadotrophique des grains de pollen des palmiers-dattiers est extraite avec de l'acétone. On a constaté qu'un g de pollen contient 1,05 I.U. de LH et 0,80 I.U. de FSH. L'activité combinée des deux fractions augmente leur effet qui atteint jusqu'à 10 I.U. HCG par g.     

Implementing Action Research in EFL/ESL Classrooms: a Systematic Review of Literature 2010–2019

Systemic Practice and Action Research - Action research studies in education often address learners’ needs and empower practitioners to effectively change instructional practices and school...