Gap junction inhibition by heptanol increases ventricular arrhythmogenicity by reducing conduction velocity without affecting repolarization properties or myocardial refractoriness in Langendorff-perfused mouse hearts.

This is the final version of the article. It first appeared from Spandidos via https://doi.org/ 10.3892/mmr.2016.5738In the current study, arrhythmogenic effects of the gap junction inhibitor heptanol (0.05 mM) were examined in Langendorff-perfused mouse hearts. Monophasic action potential recordings were obtained from the left ventricular epicardium during right ventricular pacing. Regular activity was observed both prior and subsequent to application of heptanol in all of the 12 hearts studied during 8 Hz pacing. By contrast, induced ventricular tachycardia (VT) was observed after heptanol treatment in 6/12 hearts using a S1S2 protocol (Fisher's exact test; P0.05). Consequently, excitation wavelengths (λ; CV x ERP) were reduced from 9.1±0.6 to 6.5±0.6 mm (P0.05). Together, these observations demonstrate for the first time, to the best of our knowledge, that inhibition of gap junctions alone using a low heptanol concentration (0.05 mM) was able to reduce CV, which alone was sufficient to permit the induction of VT using premature stimulation by reducing λ, which therefore appears central in the determination of arrhythmic tendency.GT was awarded a BBSRC Doctoral Training Award at the University of Cambridge

How Well Do All Patient Refined–Diagnosis-Related Groups Explain Costs of Pediatric Cancer Chemotherapy Admissions in the United States?

Purpose: State-based Medicaid programs have begun using All Patient Refined–Diagnosis-Related Groups (APR-DRGs) to determine hospital reimbursement rates. Medicaid provides coverage for 45% of childhood cancer admissions. This study aimed to examine how well APR-DRGs reflect admission costs for childhood cancer chemotherapy to inform clinicians, hospitals, and policymakers in the wake of policy changes.Methods: We identified 25,613 chemotherapy admissions in the 2009 Kids’ Inpatient Database. To determine how well APR-DRGs explain costs, we applied a hierarchic linear regression model of hospital costs, allowing for a variety of patient, hospital, and geographic confounders.Results: APR-DRGs proved to be the most important predictors of admission costs (P <.001), with costs increasing by DRG severity code. Diagnosis, age, and hospital characteristics also predicted costs above and beyond those explained by APR-DRGs. Compared with admissions for patients with acute lymphoblastic leukemia, costs of admissions for patients with acute myelomonocytic leukemia were 82% higher; non-Hodgkin lymphoma, 20% higher; Hodgkin lymphoma, 25% lower; and CNS tumors, 27% lower. Admissions for children who were 10 years of age or older cost 26% to 35% more than admissions for infants. Admissions to children’s hospitals cost 46% more than admissions to other hospital types.Conclusion: APR-DRGs developed for adults are applicable to childhood cancer chemotherapy but should be refined to account for cancer diagnosis and patient age. Possible policy and clinical management changes merit further study to address factors not captured by APR-DRGs

Full Implementation of the Secondary 1 Program of Project P.A.T.H.S.: Observations Based on the Co-Walker Scheme

This study was conducted in order to understand the implementation quality of the Secondary 1 Program of the Tier 1 Program of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes) in the first year of the Full Implementation Phase. Classroom observations of 137 units in 85 schools were conducted under the Co-Walker Scheme. Results showed that the overall level of program adherence was generally high, with an average of 86.57%. Thirteen aspects concerning program delivery were significantly correlated. Multiple regression analyses revealed that (1) overall implementation quality was significantly predicted by interactive delivery method, use of positive and supportive feedback, opportunity for reflection, degree of achievement of the objectives, and lesson preparation; whereas (2) success of implementation was significantly predicted by student interest, interactive delivery method, use of positive and supportive feedback, opportunity for reflection, and degree of achievement of the objectives. In general, the present study suggests that the implementation quality of the Project P.A.T.H.S. is good

Late-Stage Diagenetic Concretions in the Murray Formation, Gale Crater, Mars

Concretions are prevalent features in the generally lacustrine deposits of the Murray formation in Gale crater. In this work, we document the morphologic, textural, and chemical properties of these concretions throughout 300 m of Murray formation stratigraphy from Mars Science Laboratory observations between Sols 750–1900. We interpret these observations to constrain the timing and composition of post-depositional fluid events at Gale crater. We determine that the overall diversity of concretion morphology, size, texture, and chemistry throughout the Murray formation indicates that concretions formed in multiple, likely late diagenetic, episodes with varying fluid chemistries. Four major concretion assemblages are observed at distinct stratigraphic intervals and approximately correlate with major distinct chemical enrichments in Mg-S-Ni-Cl, Mn-P, and Ca-S, among other local enrichments. Different concretion size populations and complex relationships between concretions and veins also suggest multiple precipitation events at Gale crater. Many concretions likely formed during late diagenesis after sediment compaction and lithification, based on observations of concretions preserving primary host rock laminations without differential compaction. An upsection decrease in overall concretion size corresponds to an inferred upsection decrease in porosity and permeability, thus constraining concretion formation as postdating fluid events that produced initial cementation and porosity loss. The combined observations of late diagenetic concretions and distinct chemical enrichments related to concretions allow constraints to be placed on the chemistry of late stage fluids at Gale crater. Collectively, concretion observations from this work and previous studies of other diagenetic features (veins, alteration halos) suggest at least six post-depositional events that occurred at Gale crater after the deposition of the Murray formation

Discovery of Shiga Toxin-Producing Escherichia coli (STEC)-Specific Bacteriophages From Non-fecal Composts Using Genomic Characterization

Composting is a complex biodegradable process that converts organic materials into nutrients to facilitate crop yields, and, if well managed, can render bactericidal effects. Majority of research focused on detection of enteric pathogens, such as Shiga toxin-producing Escherichia coli (STEC) in fecal composts. Recently, attention has been emphasized on bacteriophages, such as STEC-specific bacteriophages, associated with STEC from the fecal-contaminated environment because they are able to sustain adverse environmental condition during composting process. However, little is known regarding the isolation of STEC-specific bacteriophages in non-fecal composts. Thus, the objectives were to isolate and genomically characterize STEC-specific bacteriophages, and to evaluate its association with STEC in non-fecal composts. For bacteriophage isolation, the samples were enriched with non-pathogenic E. coli (3 strains) and STEC (14 strains), respectively. After purification, host range, plaque size, and phage morphology were examined. Furthermore, bacteriophage genomes were subjected to whole-genome sequencing using Illumina MiSeq and genomic analyses. Isolation of top six non-O157 and O157 STEC utilizing culture methods combined with PCR-based confirmation was also conducted. The results showed that various STEC-specific bacteriophages, including vB_EcoM-Ro111lw, vB_EcoM-Ro121lw, vB_EcoS-Ro145lw, and vB_EcoM-Ro157lw, with different but complementary host ranges were isolated. Genomic analysis showed the genome sizes varied from 42kb to 149kb, and most bacteriophages were unclassified at the genus level, except vB_EcoM-Ro111lw as FelixO1-like viruses. Prokka predicted less than 25% of the ORFs coded for known functions, including those essential for DNA replication, bacteriophage structure, and host cell lysis. Moreover, none of the bacteriophages harbored lysogenic genes or virulence genes, such as stx or eae. Additionally, the presence of these lytic bacteriophages was likely attributed to zero isolation of STEC and could also contribute to additional antimicrobial effects in composts, if the composting process was insufficient. Current findings indicate that various STEC-specific bacteriophages were found in the non-fecal composts. In addition, the genomic characterization provides in-depth information to complement the deficiency of biological features regarding lytic cycle of the new bacteriophages. Most importantly, these bacteriophages have great potential to control various serogroups of STEC

VHL and PTEN loss coordinate to promote mouse liver vascular lesions

Von Hippel-Lindau (VHL) inactivation develops a tumor syndrome characterized by highly vascularized tumors as a result of hypoxia inducible factors (HIF) stabilization. The most common manifestation is the development of hemangioblastomas typically located in the central nervous system and other organs including the liver. PTEN (Phosphatase and tension homologue deleted on chromosome 10) inactivation also upregulates HIF-1α and may take part in promoting vascular lesions in tumors. The coordinate effect of loss of these tumor suppressors on HIF levels, and the subsequent effect on vascular lesion formation would elucidate the potential for mechanisms to modify HIF dosage supplementally and impact tumor phenotype. We therefore employed models of somatic conditional inactivation of Vhl, Pten, or both tumor suppressor genes in individual cells of the liver by Cre-loxP recombination to study the cooperativity of these two tumor suppressors in preventing tumor formation. Nine months after tumor suppressor inactivation, Vhl conditional deletion (VhlloxP/loxP) mice showed no abnormalities, Pten conditional deletion (PtenloxP/loxP) mice developed liver steatosis and focal nodular expansion of hepatocytes containing lipid droplet and fat. Vhl and Pten conditional deletion (VhlloxP/loxP; PtenloxP/loxP) mice, however, developed multiple cavernous liver lesions reminiscent of hemangioblastoma. Liver hemangioblastomas in VHL disease may, therefore, require secondary mutation in addition to VHL loss of heterozygosity which is permissive for vascular lesion development or augments levels of HIF-1α

Correlative multi-scale cryo-imaging unveils SARS-CoV-2 assembly and egress.

Funder: Medical Research CouncilSince the outbreak of the SARS-CoV-2 pandemic, there have been intense structural studies on purified viral components and inactivated viruses. However, structural and ultrastructural evidence on how the SARS-CoV-2 infection progresses in the native cellular context is scarce, and there is a lack of comprehensive knowledge on the SARS-CoV-2 replicative cycle. To correlate cytopathic events induced by SARS-CoV-2 with virus replication processes in frozen-hydrated cells, we established a unique multi-modal, multi-scale cryo-correlative platform to image SARS-CoV-2 infection in Vero cells. This platform combines serial cryoFIB/SEM volume imaging and soft X-ray cryo-tomography with cell lamellae-based cryo-electron tomography (cryoET) and subtomogram averaging. Here we report critical SARS-CoV-2 structural events - e.g. viral RNA transport portals, virus assembly intermediates, virus egress pathway, and native virus spike structures, in the context of whole-cell volumes revealing drastic cytppathic changes. This integrated approach allows a holistic view of SARS-CoV-2 infection, from the whole cell to individual molecules