To bite the hand that feeds you: A case of thrombotic microangiopathy due to Tiger snake bite.

This report details the case of a 51-year-old man with a Tiger snake bite who developed systemic envenomation, coagulopathy and thrombotic microangiopathy (TMA) requiring renal replacement therapy. He received plasma exchange as additional therapy while awaiting confirmation of the cause of the TMA. We discuss clinical decision making in detection of systemic envenomation and management of the rare complication of TMA, as well as current Australian guidelines around antivenom administration. This is the fourth known documented case of TMA from a Tiger snake bite in Australia.

Retrospective Use of Patients' Characteristics to Assess Variation in Prenatal Care Utilization.

OBJECTIVE: We used patients' medical and psychosocial risk factors to explore prenatal care utilization and health outcomes to inform prenatal care tailoring. STUDY DESIGN: This retrospective cohort study assessed patients who gave birth at an academic institution from January 1 to December 31, 2018, using electronic health record (EHR) data. Patients were categorized into four phenotypes based on medical/psychosocial risk factors available in the EHR: Completely low risk; High psychosocial risk only; High medical risk only; and Completely high risk. We examined patient characteristics, visit utilization, nonvisit utilization (e.g., phone calls), and outcomes (e.g., preterm birth, preeclampsia) across groups. RESULTS: Of 4,681 patients, the majority were age 18 to 35 (3,697, 79.0%), White (3,326, 70.9%), multiparous (3,263, 69.7%), and Completely high risk (2,752, 58.8%). More Black and Hispanic patients had psychosocial risk factors than White patients. Patients with psychosocial risk factors had fewer prenatal visits (10, interquartile range [IQR]: 8-12) than those without (11, IQR: 9-12). Patients with psychosocial risk factors experienced less time in prenatal care, more phone calls, and fewer EHR messages across the same medical risk group. Rates of preterm birth and gestational hypertension were incrementally higher with additional medical/psychosocial risk factors. CONCLUSION: Data readily available in the EHR can assess the compounding influence of medical/psychosocial risk factor on patients' care utilization and outcomes. KEY POINTS: · Medical and psychosocial needs in pregnancy can inform patient phenotypes and are associated with prenatal care use and outcomes.. · Patient phenotypes are associated with prenatal care use and outcomes.. · Patients with high psychosocial risk spent less time in prenatal care and had more phone calls in pregnancy.. · Tailored prenatal care models may proactively address differences in patient's needs..

Diffuse large B-cell lymphoma: a consensus practice statement from the Australasian Lymphoma Alliance.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, accounting for 30-40% of lymphoma diagnoses. Although aggressive, cure is achievable in approximately 60% of cases with primary chemoimmunotherapy, and in a further substantial minority by salvage therapy and autologous stem cell transplantation. Despite promising activity in early phase clinical trials, no intensified or novel treatment regimen has improved outcomes over R-CHOP21 in randomised studies. However, there remain several areas of controversy including the most appropriate prognostic markers, central nervous system prophylaxis and the optimal treatment for patients with high-risk disease. This position statement presents an evidence-based synthesis of the literature for application in Australasian practice.

Metal-free class Ie ribonucleotide reductase from pathogens initiates catalysis with a tyrosine-derived dihydroxyphenylalanine radical.

All cells obtain 2'-deoxyribonucleotides for DNA synthesis through the activity of a ribonucleotide reductase (RNR). The class I RNRs found in humans and pathogenic bacteria differ in (i) use of Fe(II), Mn(II), or both for activation of the dinuclear-metallocofactor subunit, ß; (ii) reaction of the reduced dimetal center with dioxygen or superoxide for this activation; (iii) requirement (or lack thereof) for a flavoprotein activase, NrdI, to provide the superoxide from O2; and (iv) use of either a stable tyrosyl radical or a high-valent dimetal cluster to initiate each turnover by oxidizing a cysteine residue in the α subunit to a radical (Cys•). The use of manganese by bacterial class I, subclass b-d RNRs, which contrasts with the exclusive use of iron by the eukaryotic Ia enzymes, appears to be a countermeasure of certain pathogens against iron deprivation imposed by their hosts. Here, we report a metal-free type of class I RNR (subclass e) from two human pathogens. The Cys• in its α subunit is generated by a stable, tyrosine-derived dihydroxyphenylalanine radical (DOPA•) in ß. The three-electron oxidation producing DOPA• occurs in Escherichia coli only if the ß is coexpressed with the NrdI activase encoded adjacently in the pathogen genome. The independence of this new RNR from transition metals, or the requirement for a single metal ion only transiently for activation, may afford the pathogens an even more potent countermeasure against transition metal-directed innate immunity.

Developing and implementing core competencies in children's environmental health for students, trainees and healthcare providers: a narrative review.

Knowledge of the health impacts of environmental exposures (such as pollution disasters, poor air quality, water contamination, climate change) on children's health has dramatically increased in the past 40 years. The World Health Organization (WHO) estimated that 23% of all deaths worldwide were attributable to the environment, and 26% of deaths in children less than 5 years old could be prevented with removal of environmental risks factors. Yet, little has permeated medical education, leaving pediatric providers ill equipped to address these issues. To address this gap, members from the Pediatric Environmental Health Specialty Units, a United States nationwide network of academically affiliated experts who have created numerous environmental health educational materials and programs, have identified fifteen core environmental health (EH) competencies needed by health care providers to enable them to effectively address environmental health concerns. These competencies can serve as the foundation for the development and implementation of relevant educational programs. The core EH competencies are based upon these foundational elements: 1) Definition of "children's environmental health" that describes how environmental exposures (positive and negative) in early life influence the health and development in childhood and across the entire human life span 2) Children are not "little adults" and so have unique vulnerabilities to environmental hazards; 3) Environmental health inequities exist, causing some children to have a disproportionate amount of unhealthy exposures and consequently a greater risk of adverse effects; 4) Climate change will translate to numerous adverse health effects that will particularly affect children worldwide. In this article, the authors describe the core environmental health competencies and provide resources, online tools, strategies, and examples targeted to all levels of training and practice to better enable leaders and educators to bring this important content to the forefront.

Structures of Class Id Ribonucleotide Reductase Catalytic Subunits Reveal a Minimal Architecture for Deoxynucleotide Biosynthesis.

Class I ribonucleotide reductases (RNRs) share a common mechanism of nucleotide reduction in a catalytic α subunit. All RNRs initiate catalysis with a thiyl radical, generated in class I enzymes by a metallocofactor in a separate ß subunit. Class Id RNRs use a simple mechanism of cofactor activation involving oxidation of a MnII2 cluster by free superoxide to yield a metal-based MnIIIMnIV oxidant. This simple cofactor assembly pathway suggests that class Id RNRs may be representative of the evolutionary precursors to more complex class Ia-c enzymes. X-ray crystal structures of two class Id α proteins from Flavobacterium johnsoniae ( Fj) and Actinobacillus ureae ( Au) reveal that this subunit is distinctly small. The enzyme completely lacks common N-terminal ATP-cone allosteric motifs that regulate overall activity, a process that normally occurs by dATP-induced formation of inhibitory quaternary structures to prevent productive ß subunit association. Class Id RNR activity is insensitive to dATP in the Fj and Au enzymes evaluated here, as expected. However, the class Id α protein from Fj adopts higher-order structures, detected crystallographically and in solution. The Au enzyme does not exhibit these quaternary forms. Our study reveals structural similarity between bacterial class Id and eukaryotic class Ia α subunits in conservation of an internal auxiliary domain. Our findings with the Fj enzyme illustrate that nucleotide-independent higher-order quaternary structures can form in simple RNRs with truncated or missing allosteric motifs.

Biochemical and Structural Characterization of XoxG and XoxJ and Their Roles in Lanthanide-Dependent Methanol Dehydrogenase Activity.

Lanthanide (Ln)-dependent methanol dehydrogenases (MDHs) have recently been shown to be widespread in methylotrophic bacteria. Along with the core MDH protein, XoxF, these systems contain two other proteins, XoxG (a c-type cytochrome) and XoxJ (a periplasmic binding protein of unknown function), about which little is known. In this work, we have biochemically and structurally characterized these proteins from the methyltroph Methylobacterium extorquens AM1. In contrast to results obtained in an artificial assay system, assays of XoxFs metallated with LaIII , CeIII , and NdIII using their physiological electron acceptor, XoxG, display Ln-independent activities, but the Km for XoxG markedly increases from La to Nd. This result suggests that XoxG's redox properties are tuned specifically for lighter Lns in XoxF, an interpretation supported by the unusually low reduction potential of XoxG (+172 mV). The X-ray crystal structure of XoxG provides a structural basis for this reduction potential and insight into the XoxG-XoxF interaction. Finally, the X-ray crystal structure of XoxJ reveals a large hydrophobic cleft and suggests a role in the activation of XoxF. These studies enrich our understanding of the underlying chemical principles that enable the activity of XoxF with multiple lanthanides in vitro and in vivo.

Opportunistic screening for alcohol use problems in adolescents attending emergency departments: an evaluation of screening tools.

OBJECTIVE: To estimate and compare the optimal cut-off score of Alcohol Use Disorders Identification Test (AUDIT) and AUDIT-C in identifying at-risk alcohol consumption, heavy episodic alcohol use, ICD-10 alcohol abuse and alcohol dependence in adolescents attending ED in England. DESIGN: Opportunistic cross-sectional survey. SETTING: 10 emergency departments across England. PARTICIPANTS: Adolescents (n = 5377) aged between their 10th and 18th birthday who attended emergency departments between December 2012 and May 2013. MEASURES: Scores on the AUDIT and AUDIT-C. At-risk alcohol consumption and monthly episodic alcohol consumption in the past 3 months were derived using the time-line follow back method. Alcohol abuse and alcohol dependence was assessed in accordance with ICD-10 criteria using the MINI-KID. FINDINGS: AUDIT-C with a score of 3 was more effective for at-risk alcohol use (AUC 0.81; sensitivity 87%, specificity 97%), heavy episodic use (0.84; 76%, 98%) and alcohol abuse (0.98; 91%, 90%). AUDIT with a score of 7 was more effective in identifying alcohol dependence (0.92; 96%, 94%). CONCLUSIONS: The 3-item AUDIT-C is more effective than AUDIT in screening adolescents for at-risk alcohol use, heavy episodic alcohol use and alcohol abuse. AUDIT is more effective than AUDIT-C for the identification of alcohol dependence.

Structural Basis for Superoxide Activation of Flavobacterium johnsoniae Class I Ribonucleotide Reductase and for Radical Initiation by Its Dimanganese Cofactor.

A ribonucleotide reductase (RNR) from Flavobacterium johnsoniae ( Fj) differs fundamentally from known (subclass a-c) class I RNRs, warranting its assignment to a new subclass, Id. Its ß subunit shares with Ib counterparts the requirements for manganese(II) and superoxide (O2-) for activation, but it does not require the O2--supplying flavoprotein (NrdI) needed in Ib systems, instead scavenging the oxidant from solution. Although Fj ß has tyrosine at the appropriate sequence position (Tyr 104), this residue is not oxidized to a radical upon activation, as occurs in the Ia/b proteins. Rather, Fj ß directly deploys an oxidized dimanganese cofactor for radical initiation. In treatment with one-electron reductants, the cofactor can undergo cooperative three-electron reduction to the II/II state, in contrast to the quantitative univalent reduction to inactive "met" (III/III) forms seen with I(a-c) ßs. This tendency makes Fj ß unusually robust, as the II/II form can readily be reactivated. The structure of the protein rationalizes its distinctive traits. A distortion in a core helix of the ferritin-like architecture renders the active site unusually open, introduces a cavity near the cofactor, and positions a subclass-d-specific Lys residue to shepherd O2- to the Mn2II/II cluster. Relative to the positions of the radical tyrosines in the Ia/b proteins, the unreactive Tyr 104 of Fj ß is held away from the cofactor by a hydrogen bond with a subclass-d-specific Thr residue. Structural comparisons, considered with its uniquely simple mode of activation, suggest that the Id protein might most closely resemble the primordial RNR-ß.

Genome Plasticity of agr-Defective Staphylococcus aureus during Clinical Infection.

Therapy for bacteremia caused by Staphylococcus aureus is often ineffective, even when treatment conditions are optimal according to experimental protocols. Adapted subclones, such as those bearing mutations that attenuate agr-mediated virulence activation, are associated with persistent infection and patient mortality. To identify additional alterations in agr-defective mutants, we sequenced and assembled the complete genomes of clone pairs from colonizing and infected sites of several patients in whom S. aureus demonstrated a within-host loss of agr function. We report that events associated with agr inactivation result in agr-defective blood and nares strain pairs that are enriched in mutations compared to pairs from wild-type controls. The random distribution of mutations between colonizing and infecting strains from the same patient, and between strains from different patients, suggests that much of the genetic complexity of agr-defective strains results from prolonged infection or therapy-induced stress. However, in one of the agr-defective infecting strains, multiple genetic changes resulted in increased virulence in a murine model of bloodstream infection, bypassing the mutation of agr and raising the possibility that some changes were selected. Expression profiling correlated the elevated virulence of this agr-defective mutant to restored expression of the agr-regulated ESAT6-like type VII secretion system, a known virulence factor. Thus, additional mutations outside the agr locus can contribute to diversification and adaptation during infection by S. aureus agr mutants associated with poor patient outcomes.

Climate-driven changes to the spatio-temporal distribution of the parasitic nematode, Haemonchus contortus, in sheep in Europe.

Recent climate change has resulted in changes to the phenology and distribution of invertebrates worldwide. Where invertebrates are associated with disease, climate variability and changes in climate may also affect the spatio-temporal dynamics of disease. Due to its significant impact on sheep production and welfare, the recent increase in diagnoses of ovine haemonchosis caused by the nematode Haemonchus contortus in some temperate regions is particularly concerning. This study is the first to evaluate the impact of climate change on H. contortus at a continental scale. A model of the basic reproductive quotient of macroparasites, Q0 , adapted to H. contortus and extended to incorporate environmental stochasticity and parasite behaviour, was used to simulate Pan-European spatio-temporal changes in H. contortus infection pressure under scenarios of climate change. Baseline Q0 simulations, using historic climate observations, reflected the current distribution of H. contortus in Europe. In northern Europe, the distribution of H. contortus is currently limited by temperatures falling below the development threshold during the winter months and within-host arrested development is necessary for population persistence over winter. In southern Europe, H. contortus infection pressure is limited during the summer months by increased temperature and decreased moisture. Compared with this baseline, Q0 simulations driven by a climate model ensemble predicted an increase in H. contortus infection pressure by the 2080s. In northern Europe, a temporal range expansion was predicted as the mean period of transmission increased by 2-3 months. A bimodal seasonal pattern of infection pressure, similar to that currently observed in southern Europe, emerges in northern Europe due to increasing summer temperatures and decreasing moisture. The predicted patterns of change could alter the epidemiology of H. contortus in Europe, affect the future sustainability of contemporary control strategies, and potentially drive local adaptation to climate change in parasite populations.

A Validated Open-Source Multisolver Fourth-Generation Composite Femur Model.

Synthetic biomechanical test specimens are frequently used for preclinical evaluation of implant performance, often in combination with numerical modeling, such as finite-element (FE) analysis. Commercial and freely available FE packages are widely used with three FE packages in particular gaining popularity: abaqus (Dassault Systèmes, Johnston, RI), ansys (ANSYS, Inc., Canonsburg, PA), and febio (University of Utah, Salt Lake City, UT). To the best of our knowledge, no study has yet made a comparison of these three commonly used solvers. Additionally, despite the femur being the most extensively studied bone in the body, no freely available validated model exists. The primary aim of the study was primarily to conduct a comparison of mesh convergence and strain prediction between the three solvers (abaqus, ansys, and febio) and to provide validated open-source models of a fourth-generation composite femur for use with all the three FE packages. Second, we evaluated the geometric variability around the femoral neck region of the composite femurs. Experimental testing was conducted using fourth-generation Sawbones® composite femurs instrumented with strain gauges at four locations. A generic FE model and four specimen-specific FE models were created from CT scans. The study found that the three solvers produced excellent agreement, with strain predictions being within an average of 3.0% for all the solvers (r2 > 0.99) and 1.4% for the two commercial codes. The average of the root mean squared error against the experimental results was 134.5% (r2 = 0.29) for the generic model and 13.8% (r2 = 0.96) for the specimen-specific models. It was found that composite femurs had variations in cortical thickness around the neck of the femur of up to 48.4%. For the first time, an experimentally validated, finite-element model of the femur is presented for use in three solvers. This model is freely available online along with all the supporting validation data.

Cytotoxic Virulence Predicts Mortality in Nosocomial Pneumonia Due to Methicillin-Resistant Staphylococcus aureus.

The current study identified bacterial factors that may improve management of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. Isolates were obtained from 386 patients enrolled in a randomized, controlled study of antibiotic efficacy. Isolates were screened for production of virulence factors and for vancomycin susceptibility. After adjustment for host factors such as severity of illness and treatment modality, cytotoxic activity was strongly and inversely associated with mortality; however, it had no effect on clinical cure. Isolates having low cytotoxicity, which were derived largely from healthcare-associated clones, exhibited a greater prevalence of vancomycin heteroresistance, and they were recovered more often from patients who were older and frailer. Additionally, a clone with low cytotoxic activity was associated with death and poor clinical improvement. Clone specificity and attenuated virulence appear to be associated with outcome. To our knowledge, these are the first correlations between MRSA virulence and mortality in nosocomial pneumonia.

Asynchrony in host and parasite phenology may decrease disease risk in livestock under climate warming: Nematodirus battus in lambs as a case study.

Mismatch in the phenology of trophically linked species as a result of climate warming has been shown to have far-reaching effects on animal communities, but implications for disease have so far received limited attention. This paper presents evidence suggestive of phenological asynchrony in a host-parasite system arising from climate change, with impacts on transmission. Diagnostic laboratory data on outbreaks of infection with the pathogenic nematode Nematodirus battus in sheep flocks in the UK were used to validate region-specific models of the effect of spring temperature on parasite transmission. The hatching of parasite eggs to produce infective larvae is driven by temperature, while the availability of susceptible hosts depends on lambing date, which is relatively insensitive to inter-annual variation in spring temperature. In southern areas and in warmer years, earlier emergence of infective larvae in spring was predicted, with decline through mortality before peak availability of susceptible lambs. Data confirmed model predictions, with fewer outbreaks recorded in those years and regions. Overlap between larval peaks and lamb availability was not reduced in northern areas, which experienced no decreases in the number of reported outbreaks. Results suggest that phenological asynchrony arising from climate warming may affect parasite transmission, with non-linear but predictable impacts on disease burden. Improved understanding of complex responses of host-parasite systems to climate change can contribute to effective adaptation of parasite control strategies.

Management of very high risk pregnancy with secondary anti-phospholipid syndrome and triple positivity to the anti-phospholipid antibodies.

There is a significantly increased risk of pregnancy complications in women with anti-phospholipid syndrome (APS). The risk is further heightened in those with previous arterial or venous thromboembolism and so-called 'triple positivity' for anti-phospholipid antibodies (i.e., when lupus anticoagulant, and anti-cardiolipin (aCL) and anti-ß2 glycoprotein-I (anti-ß2Gp-I) antibodies are all detected). Management of these cases is extremely difficult and little is available in the medical literature to guide therapy. This report describes the use of regular plasma exchanges (PEx) to bring about a successful pregnancy outcome in a woman with secondary APS and previous recurrent miscarriages. The patient was also anticoagulated with enoxaparin and administered aspirin, prednisolone, azathioprine and hydroxychloroquine. Through regular PEx and immunomodulation therapy, levels of aCL and anti-ß2Gp-I antibodies were monitored and documented to fall as pregnancy progressed. Although the outcome in this case was successful, further experience is required before this regimen can be accepted as the standard of care for these patients at very high risk of pregnancy loss.

Incidentally detected thrombocytopaenia in adults.

BACKGROUND: With the advent of automated counters, low platelet counts are a common incidental finding. The list of possible aetiologies is long and exhaustive (Figure 1, available online only). Platelet abnormalities range from having no clinical relevance to being the only initial manifestation of a serious underlying disorder. OBJECTIVE: This article provides general practitioners with an approach to differentiating the benign from the life-threatening causes of thrombocytopenia using routine pathology testing in adults. DISCUSSION: There are no specific laboratory tests that can conclusively identify the mechanism of thrombocytopenia - a thorough history, clinical examination, and blood results remain the initial means of diagnosis.

Classic Whipple disease presenting as genuine pyrexia of unknown origin following immunosuppression with adalimumab.

Whipple disease (WD) is a rare chronic multisystem infectious disorder caused by the bacterium Tropheryma whipplei (T. whipplei) and is more prevalent than previously thought. Its diagnosis is often delayed by months to years owing to its rarity, non-specific manifestations and insidious course. WD classically presents with polyarthropathy followed months to years later by the development of gastrointestinal symptoms, which often lead to the diagnosis. Pyrexia of unknown origin (PUO) without gastrointestinal involvement is an extremely rare presentation. We describe a case of WD presenting as genuine PUO following immunosuppression with the tumour necrosis factor-alpha monoclonal antibody adalimumab for seronegative polyarthropathy.

Case report of a pan-cytokeratin negative NUT midline carcinoma of pulmonary origin, a BRD3-NUT variant: Challenges in cytomorphologic presentation.

NUT carcinoma is an aggressive malignancy defined genetically by a balanced translocation of the NUT gene on chromosome 15q14, most commonly associated with the bromodomain-containing protein 4 (BRD4) gene on 19p13.1 but less frequently with variant genes, including BRD3 and NSD-3. We present a case report of a metastatic pulmonary NUT carcinoma found to have a BRD3-NUT fusion and to have only focal pan-cytokeratin staining. Biopsy of the pulmonary mass revealed dyscohesive cells with enlarged nuclei, prominent nucleoli and high nuclear to cytoplasmic ratio without areas of squamous differentiation. Initial immunohistochemical stains were positive for NUT, p63 and retained SMARCA4, while negative for Lu-5 (pan-cytokeratin), TTF-1, p40, S100 protein, OCT-4, HMB-45, SMA, and PAX-8. Tempus ×T assay revealed a BRD3-NUTM1 fusion gene. Post-mortem analysis revealed an ill-defined mass abutting the trachea and superior vena cava, as well as a perirenal mass.