ATS Core Curriculum 2021. Pediatric Pulmonary Medicine: Pulmonary Infections

The following is a concise review of the Pediatric Pulmonary Medicine Core reviewing pediatric pulmonary infections, diagnostic assays, and imaging techniques presented at the 2021 American Thoracic Society Core Curriculum. Molecular methods have revolutionized microbiology. We highlight the need to collect appropriate samples for detection of specific pathogens or for panels and understand the limitations of the assays. Considerable progress has been made in imaging modalities for detecting pediatric pulmonary infections. Specifically, lung ultrasound and lung magnetic resonance imaging are promising radiation-free diagnostic tools, with results comparable with their radiation-exposing counterparts, for the evaluation and management of pulmonary infections. Clinicians caring for children with pulmonary disease should ensure that patients at risk for nontuberculous mycobacteria disease are identified and receive appropriate nontuberculous mycobacteria screening, monitoring, and treatment. Children with coronavirus disease (COVID-19) typically present with mild symptoms, but some may develop severe disease. Treatment is mainly supportive care, and most patients make a full recovery. Anticipatory guidance and appropriate counseling from pediatricians on social distancing and diagnostic testing remain vital to curbing the pandemic. The pediatric immunocompromised patient is at risk for invasive and opportunistic pulmonary infections. Prompt recognition of predisposing risk factors, combined with knowledge of clinical characteristics of microbial pathogens, can assist in the diagnosis and treatment of specific bacterial, viral, or fungal diseases

Diagnosis and Management of COVID-19 Disease

SARS-CoV-2 is a novel coronavirus that was identified in late 2019 as the causative agent of COVID-19 (aka coronavirus disease 2019). On March 11, 2020, the World Health Organization (WHO) declared the world-wide outbreak of COVID-19 a pandemic. This document summarizes the most recent knowledge regarding the biology, epidemiology, diagnosis, and management of COVID-19

Mixed volumes of networks with binomial steady-states

The steady-state degree of a chemical reaction network is the number of complex steady-states for generic rate constants and initial conditions. One way to bound the steady-state degree is through the mixed volume of the steady-state system or an equivalent system. In this work, we show that for partionable binomial networks, whose resulting steady-state systems are given by a set of binomials and a set of linear (not necessarily binomial) conservation equations, computing the mixed volume is equivalent to finding the volume of a single mixed cell that is the translate of a parallelotope. We then turn our attention to identifying cycles with binomial steady-state ideals. To this end, we give a coloring condition on directed cycles that guarantees the network has a binomial steady-state ideal. We highlight both of these theorems using a class of networks referred to as species-overlapping networks and give a formula for the mixed volume of these networks.Comment: 17 page

Evaluating the educational impact of pre- and post-visit activities on elementary students following a field trip to a public garden

Many public gardens offer tours to schoolchildren. Informal educators argue that preparing students for a field trip by providing pre- and post-visit activities can positively impact learning. However, there is little research that supports the efficacy of pre- and post-visit activities on learning at public gardens. Therefore, the purpose of this research was to determine the impact of pre- and post-visit activities on learning after a field trip to a public garden. This quasi-experimental study\u27s population included four fifth-grade classrooms assigned to one of two treatments: 1) a field trip only (control) and 2) a field trip with pre- and post-visit activities (treatment). A post-trip assessment consisted of open-ended questions and was scored quantitatively. Differences between treatment groups were analyzed by using a t-test. Findings indicated that there was no significant difference in post-test scores between the treatment groups. Although pre- and post-visit activities have been found to prepare students for a field trip and to tie the field trip to classroom learning, this case study did not show an increase in learning outcomes. A limitation of this research was the small number of students involved and should be conducted again with more students. However, the novel method of analysis may have implications for assessing what students learn on field trips to informal settings. This research has implications for informal education settings such as public gardens, botanical centers, and arboreta that seek to measure visitor learning

Impact of cyber-invasive species on a large ecological network

As impacts of introduced species cascade through trophic levels, they can cause indirect and counter-intuitive effects. To investigate the impact of invasive species at the network scale, we use a generalized food web model, capable of propagating changes through networks with a series of ecologically realistic criteria. Using data from a small British offshore island, we quantify the impacts of four virtual invasive species (an insectivore, a herbivore, a carnivore and an omnivore whose diet is based on a rat) and explore which clusters of species react in similar ways. We find that the predictions for the impacts of invasive species are ecologically plausible, even in large networks. Species in the same taxonomic group are similarly impacted by a virtual invasive species. However, interesting differences within a given taxonomic group can occur. The results suggest that some native species may be at risk from a wider range of invasives than previously believed. The implications of these results for ecologists and land managers are discussed

The absence of myocardial calcium-independent phospholipase a2γ results in impaired prostaglandin e2 production and decreased survival in mice with acute trypanosoma cruzi infection

Cardiomyopathy is a serious complication of Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi. The parasite often infects cardiac myocytes, causing the release of inflammatory mediators, including eicosanoids. A recent study from our laboratory demonstrated that calcium-independent phospholipase A(2)γ (iPLA(2)γ) accounts for the majority of PLA(2) activity in rabbit ventricular myocytes and is responsible for arachidonic acid (AA) and prostaglandin E(2) (PGE(2)) release. Thus, we hypothesized that cardiac iPLA(2)γ contributes to eicosanoid production in T. cruzi infection. Inhibition of the isoform iPLA(2)γ or iPLA(2)β, with the R or S enantiomer of bromoenol lactone (BEL), respectively, demonstrated that iPLA(2)γ is the predominant isoform in immortalized mouse cardiac myocytes (HL-1 cells). Stimulation of HL-1 cells with thrombin, a serine protease associated with microthrombus formation in Chagas' disease and a known activator of iPLA(2), increased AA and PGE(2) release, accompanied by platelet-activating factor (PAF) production. Similarly, T. cruzi infection resulted in increased AA and PGE(2) release over time that was inhibited by pretreatment with (R)-BEL. Further, T. cruzi-infected iPLA(2)γ-knockout (KO) mice had lower survival rates and increased tissue parasitism compared to wild-type (WT) mice, suggesting that iPLA(2)γ-KO mice were more susceptible to infection than WT mice. A significant increase in iPLA(2) activity was observed in WT mice following infection, whereas iPLA(2)γ-KO mice showed no alteration in cardiac iPLA(2) activity and produced less PGE(2). In summary, these studies demonstrate that T. cruzi infection activates cardiac myocyte iPLA(2)γ, resulting in increased AA and PGE(2) release, mediators that may be essential for host survival during acute infection. Thus, these studies suggest that iPLA(2)γ plays a cardioprotective role during the acute stage of Chagas' disease

Ecology of Free-Ranging Horses in Northern Guy Fawkes River National Park NSW, Australia

This study examines spatial and temporal aspects of free-ranging horses on approximately 40 km2 of Paddy's Land plateau in northern Guy Fawkes River National Park (GFRNP). Free-ranging horse ecology within GFRNP holds particular scientific interest as, in October 2000, prolonged drought and bush fires prompted the NSW National Parks and Wildlife Service to perform a free-ranging horse control operation, in which 606 horses were culled. A scattered population remains and highest densities are thought to occur in the northern sector of the Park. Investigations into the current population and their impacts are needed to increase our understanding of the relationship free-ranging horses have with the woodland plateau. Baseline information on the densities and distribution of the horse population is presented along with the first examination of bark-chewing damage to eucalypt trees by horses. Density, habitat-use and distribution was systematically sampled by means of repeated transect surveys, implementing horse-band-counts as well as dung-counts, and by passive observational surveys. Results are consistent with anecdotal reports of a seasonal migration, of a portion of the horse population, from the gorge system to the plateau. Free-ranging horses occupied Paddy's Land plateau over all seasons reaching highest densities during the extremely dry summer of 2002-2003. They were dispersed across plateau and showed significant tendency to occupy drainage-lines, which are associated with abandoned stock ponds. Impact assessments revealed that bark-chewing damage is clustered with severity of damage along drainage-lines and in close proximity of other water sources. Investigations using transect and quadrat techniques revealed that free-ranging horses chew bark, intensely during summer demonstrating preferences for 'Eucalyptus amplifolia', 'E. saligna', and 'E. moluccana'. Damage is correlated with poor biological health of trees, which indicates that horses directly affect ecosystem health on Paddy's Land plateau. Replicated exclosures were pilot-tested in Bob's Creek to measure the effects of grazing on herbaceous vegetation. Difficulties experienced resulted in recommendations for a future design. It has been recommended by the National Parks and Wildlife Service that all free-ranging horses be removed from GFRNP, and by the Heritage Working Party that some of the horses be relocated and managed off National Park estate to retain their bloodlines. This study offers detail to support this process including, recommendations for ecosystem rehabilitation on Paddy's Land plateau. Restoring abandoned stock ponds to reconnect the seasonal drainage-lines would be a logical step, and perhaps reduce the advantage these ponds offer the free-ranging horses and other exotic ungulates. Further study of this restoration opportunity would support better management of Park resources while offering a better understanding of horse ecology in Guy Fawkes River National Park