Hypokalemia Promotes Late Phase 3 Early Afterdepolarization and Recurrent Ventricular Fibrillation During Isoproterenol Infusion in Langendorff Perfused Rabbit Ventricles

BACKGROUND Hypokalemia and sympathetic activation are commonly associated with electrical storm (ES) in normal and diseased hearts. The mechanisms remain unclear. OBJECTIVE To test the hypothesis that late phase 3 early afterdepolarization (EAD) induced by IKATP activation underlies the mechanisms of ES during isoproterenol infusion and hypokalemia. METHODS Intracellular calcium (Cai) and membrane voltage were optically mapped in 32 Langendorff-perfused normal rabbit hearts. RESULTS Repeated episodes of electrically-induced VF at baseline did not result in spontaneous VF (SVF). During isoproterenol infusion, SVF occurred in 1 of 15 hearts (7%) studied in normal extracellular potassium ([K+]o) (4.5 mmol/L), 3 of 8 hearts (38%) in 2.0 mmol/L [K+]o, 9 of 10 hearts (90%) in 1.5 mmol/L [K+]o, and 7 of 7 hearts (100%) in 1.0 mmol/L [K+]o (P<0.001). Optical mapping showed isoproterenol and hypokalemia enhanced Cai transient duration (CaiTD) and heterogeneously shortened action potential duration (APD) after defibrillation, leading to late phase 3 EAD and SVF. IKATP blocker (glibenclamide, 5 μmol/L) reversed the post-defibrillation APD shortening and suppressed recurrent SVF in all hearts studied despite no evidence of ischemia. Nifedipine reliably prevented recurrent VF when given before, but not after, the development of VF. IKr blocker (E-4031) and small conductance calcium activated potassium channel blocker (apamin) failed to prevent recurrent SVF. CONCLUSION Beta-adrenergic stimulation and concomitant hypokalemia could cause non-ischemic activation of IKATP, heterogeneous APD shortening and prolongation of CaiTD to provoke late phase 3 EAD, triggered activity and recurrent SVF. IKATP inhibition may be useful in managing ES during resistant hypokalemia

Comparative analysis of pediatric COVID-19 infection in Southeast Asia, south Asia, Japan, and China

There is a scarcity of data regarding coronavirus disease 2019 (COVID-19) infection in children from southeast and south Asia. This study aims to identify risk factors for severe COVID-19 disease among children in the region. This is an observational study of children with COVID-19 infection in hospitals contributing data to the Pediatric Acute and Critical Care COVID-19 Registry of Asia. Laboratory-confirmed COVID-19 cases were included in this registry. The primary outcome was severity of COVID-19 infection as defined by the World Health Organization (WHO) (mild, moderate, severe, or critical). Epidemiology, clinical and laboratory features, and outcomes of children with COVID-19 are described. Univariate and multivariable logistic regression models were used to identify risk factors for severe/critical disease. A total of 260 COVID-19 cases from eight hospitals across seven countries (China, Japan, Singapore, Malaysia, Indonesia, India, and Pakistan) were included. The common clinical manifestations were similar across countries: fever (64%), cough (39%), and coryza (23%). Approximately 40% of children were asymptomatic, and overall mortality was 2.3%, with all deaths reported from India and Pakistan. Using the multivariable model, the infant age group, presence of comorbidities, and cough on presentation were associated with severe/critical COVID-19. This epidemiological study of pediatric COVID-19 infection demonstrated similar clinical presentations of COVID-19 in children across Asia. Risk factors for severe disease in children were age younger than 12 months, presence of comorbidities, and cough at presentation. Further studies are needed to determine whether differences in mortality are the result of genetic factors, cultural practices, or environmental exposures

Method of zinc oxide film grown on the epitaxial lateral overgrowth gallium nitride template

US8257999Granted Paten

METHOD OF ZINC OXIDE FILM GROWN ON THE EPITAXIAL LATERAL OVERGROWTH GALLIUM NITRIDE TEMPLATE

US20120018699A1Published Applicatio

4,9-Dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-embedded electrochromic conjugated polymers with high coloration efficiency and fast coloration time

10.1016/j.solmat.2015.01.007Solar Energy Materials and Solar Cells13692-9

Effects of fluorination on the electrochromic performance of benzothiadiazole-based donor - Acceptor copolymers

10.1039/c5tc00725aJournal of Materials Chemistry C3215589-559

Loop-Mediated Isothermal Amplification Assay for Detection of Generic and Verocytotoxin-Producing Escherichia coli among Indigenous Individuals in Malaysia

We have successfully developed a Loop-mediated isothermal amplification (LAMP) assay that could specifically detect generic Escherichia coli (E. coli). This assay was tested on 85 bacterial strains and successfully identified 54 E. coli strains (average threshold time, Tt = 21.26). The sensitivity of this assay was evaluated on serial dilutions of bacterial cultures and spiked faeces. The assay could detect 102 CFU/mL for bacterial culture with Tt = 33.30 while the detection limit for spiked faeces was 103 CFU/mL (Tt = 31.12). We have also detected 46 generic E. coli from 50 faecal samples obtained from indigenous individuals with 16% of the positive samples being verocytotoxin-producing E. coli (VTEC) positive. VT1/VT2 allele was present in one faecal sample while the ratio of VT1 to VT2 was 6 : 1. Overall, our study had demonstrated high risk of VTEC infection among the indigenous community and most of the asymptomatic infection occurred among those aged below 15 years. The role of asymptomatic human carriers as a source of dissemination should not be underestimated. Large scale screening of the VTEC infection among indigenous populations and the potential contamination sources will be possible and easy with the aid of this newly developed rapid and simple LAMP assay

Loop-Mediated Isothermal Amplification Assay for Detection of Generic and Verocytotoxin-Producing Escherichia coli among Indigenous Individuals in Malaysia

We have successfully developed a Loop-mediated isothermal amplification (LAMP) assay that could specifically detect generic Escherichia coli (E. coli). This assay was tested on 85 bacterial strains and successfully identified 54 E. coli strains (average threshold time, Tt = 21.26). The sensitivity of this assay was evaluated on serial dilutions of bacterial cultures and spiked faeces. The assay could detect 10 2 CFU/mL for bacterial culture with Tt = 33.30 while the detection limit for spiked faeces was 10 3 CFU/mL (Tt = 31.12). We have also detected 46 generic E. coli from 50 faecal samples obtained from indigenous individuals with 16% of the positive samples being verocytotoxin-producing E. coli (VTEC) positive. VT1/VT2 allele was present in one faecal sample while the ratio of VT1 to VT2 was 6 : 1. Overall, our study had demonstrated high risk of VTEC infection among the indigenous community and most of the asymptomatic infection occurred among those aged below 15 years. The role of asymptomatic human carriers as a source of dissemination should not be underestimated. Large scale screening of the VTEC infection among indigenous populations and the potential contamination sources will be possible and easy with the aid of this newly developed rapid and simple LAMP assay