TNFα protects cardiac mitochondria independently of its cell surface receptors

Our novel proposal is that TNFα exerts a direct effect on mitochondrial respiratory function in the heart, independently of its cell surface receptors. TNFα-induced cardioprotection is known to involve reactive oxygen species (ROS) and sphingolipids. We therefore further propose that this direct mitochondrial effect is mediated via ROS and sphingolipids. The protective concentration of TNFα (0.5 ng/ml) was added to isolated heart mitochondria from black 6 × 129 mice (WT) and double TNF receptor knockout mice (TNFR1&2^−/−). Respiratory parameters and inner mitochondrial membrane potential were analyzed in the presence/absence of two antioxidants, N-acetyl-l-cysteine or N-tert-butyl-α-(2-sulfophenyl)nitrone or two antagonists of the sphingolipid pathway, N-oleoylethanolamine (NOE) or imipramine. In WT, TNFα reduced State 3 respiration from 279.3 ± 3 to 119.3 ± 2 (nmol O₂/mg protein/min), increased proton leak from 15.7 ± 0.6% (control) to 36.6 ± 4.4%, and decreased membrane potential by 20.5 ± 3.1% compared to control groups. In TNFR1&2^−/− mice, TNFα reduced State 3 respiration from 205.2 ± 4 to 75.7 ± 1 (p < 0.05 vs. respective control). In WT mice, both antioxidants added with TNFα restored State 3 respiration to 269.2 ± 2 and 257.6 ± 2, respectively. Imipramine and NOE also restored State 3 respiration to 248.4 ± 2 and 249.0 ± 2, respectively (p < 0.01 vs. TNFα alone). Similarly, both antioxidant and inhibitors of the sphingolipid pathway restored the proton leak to pre-TNF values. TNFα-treated mitochondria or isolated cardiac muscle fibers showed an increase in respiration after anoxia–reoxygenation, but this effect was lost in the presence of an antioxidant or NOE. Similar data were obtained in TNFR1&2^−/− mice. TNFα exerts a protective effect on respiratory function in isolated mitochondria subjected to an anoxia–reoxygenation insult. This effect appears to be independent of its cell surface receptors, but is likely to be mediated by ROS and sphingolipids.     

Impact of COVID-19 Pandemic on Training: Global Perceptions of Gastroenterology and Hepatology Fellows in the USA

Background

The COVID-19 pandemic has impacted numerous facets of healthcare workers’ lives. There have also been significant changes in Gastroenterology (GI) fellowship training as a result of the challenges presented by the pandemic.

Aims

We conducted a national survey of Gastroenterology fellows to evaluate fellows’ perceptions, changes in clinical duties, and education during the pandemic.

Methods

A survey was sent to Gastroenterology (GI) fellows in the USA. Information regarding redeployment, fellow restriction in endoscopy, outpatient clinics and inpatient consults, impact on educational activities, and available wellness resources was obtained. Fellows’ level of agreement with adjustments to clinical duties was also assessed.

Results

One hundred and seventy-seven Gastroenterology fellows responded, and 29.4% were redeployed to non-GI services during the pandemic. COVID-19 impacted all aspects of GI fellowship training in the USA (endoscopy, outpatient clinics, inpatient consults, educational activities). Fellows’ level of agreement in changes to various aspects of fellowship varied. 72.5% of respondents reported that their programs provided them with increased wellness resources to cope with the additional stress during the pandemic. For respondents with children, 17.6% reported no support with childcare.

Conclusions

Our results show that the COVID-19 pandemic has impacted GI fellowship training in the USA in multiple domains, including gastrointestinal endoscopy, inpatient consults, outpatient clinics, and educational conferences. Our study highlights the importance of considering and incorporating fellows’ viewpoints, as changes are made in response to the ongoing pandemic.

     

Increased Risk for Group B Streptococcus Sepsis in Young Infants Exposed to HIV,Soweto, South Africa, 2004–2008

Although group B Streptococcus (GBS) is a leading cause of severe invasive disease in young infants worldwide, epidemiologic data and knowledge about risk factors for the disease are lacking from low- to middle-income countries. To determine the epidemiology of invasive GBS disease among young infants in a setting with high maternal HIV infection, we conducted hospital-based surveillance during 2004–2008 in Soweto, South Africa. Overall GBS incidence was 2.72 cases/1,000 live births (1.50 and 1.22, respectively, among infants with early-onset disease [EOD] and late-onset [LOD] disease). Risk for EOD and LOD was higher for HIV-exposed than HIV-unexposed infants. GBS serotypes Ia and III accounted for 84.0% of cases, and 16.9% of infected infants died. We estimate that use of trivalent GBS vaccine (serotypes Ia, Ib, and III) could prevent 2,105 invasive GBS cases and 278 deaths annually among infants in South Africa; therefore, vaccination of all pregnant women in this country should be explored.     

Evaluation of tuberculosis diagnostics in children: 1. Proposed clinical case definitions for classification of intrathoracic tuberculosis disease. Consensus from an expert panel

There is a critical need for improved diagnosis of tuberculosis in children, particularly in young children with intrathoracic disease as this represents the most common type of tuberculosis in children and the greatest diagnostic challenge. There is also a need for standardized clinical case definitions for the evaluation of diagnostics in prospective clinical research studies that include children in whom tuberculosis is suspected but not confirmed by culture of Mycobacterium tuberculosis. A panel representing a wide range of expertise and child tuberculosis research experience aimed to develop standardized clinical research case definitions for intrathoracic tuberculosis in children to enable harmonized evaluation of new tuberculosis diagnostic technologies in pediatric populations. Draft definitions and statements were proposed and circulated widely for feedback. An expert panel then considered each of the proposed definitions and statements relating to clinical definitions. Formal group consensus rules were established and consensus was reached for each statement. The definitions presented in this article are intended for use in clinical research to evaluate diagnostic assays and not for individual patient diagnosis or treatment decisions. A complementary article addresses methodological issues to consider for research of diagnostics in children with suspected tuberculosis.     

Variation in reported neonatal group B streptococcal disease incidence in developing countries

Group B Streptococcus (GBS) is a leading cause of neonatal sepsis in developed countries. Its burden in the developing world is less clear. Studies reporting neonatal GBS disease incidence from developing countries were identified from 5 literature databases. Studies were assessed with respect to case finding and culture methods. Only 20 studies were identified. The GBS incidence ranged 0-3.06 per 1000 live births with variation within and between geographic regions. All but 1 study identified GBS cases within a hospital setting, despite the potential for births in the community. Possible case under-ascertainment was only discussed in 2 studies. A higher GBS incidence was reported when using automated culture methods. Prospective, population-based surveillance is urgently needed in developing countries to provide an accurate assessment of the neonatal GBS disease burden. This will be crucial for the design of interventions, including novel vaccines, and the understanding of their potential to impact mortality from neonatal sepsis.     

The Pneumonia Etiology Research for Child Health Project: a 21st century childhood pneumonia etiology study

The Pneumonia Etiology Research for Child Health (PERCH) project is a 7-country, standardized, comprehensive evaluation of the etiologic agents causing severe pneumonia in children from developing countries. During previous etiology studies, between one-quarter and one-third of patients failed to yield an obvious etiology; PERCH will employ and evaluate previously unavailable innovative, more sensitive diagnostic techniques. Innovative and rigorous epidemiologic and analytic methods will be used to establish the causal association between presence of potential pathogens and pneumonia. By strategic selection of study sites that are broadly representative of regions with the greatest burden of childhood pneumonia, PERCH aims to provide data that reflect the epidemiologic situation in developing countries in 2015, using pneumococcal and Haemophilus influenzae type b vaccines. PERCH will also address differences in host, environmental, and/or geographic factors that might determine pneumonia etiology and, by preserving specimens, will generate a resource for future research and pathogen discovery.