ac The ERS approach to e-cigarettes is entirely rational By erj.ersjournals.com Published On :: 2020-05-07T01:15:55-07:00 The call for the European Respiratory Society (ERS) to change their e-cigarette and vaping policy, from honourable people with decades of experience fighting the evils of tobacco, is unfortunately misconceived. The three issues of greatest concern are acute toxicity, chronic toxicity and, most importantly, the effects on children and young people. The efficacy of e-cigarettes as an adjunct to smoking cessation are outwith the expertise of paediatric specialists, but we would ask for assurances that any benefits really do outweigh the risks to children and young people (below). Our comments on these key issues are as follows: Full Article
ac A rational approach to e-cigarettes: challenging ERS policy on tobacco harm reduction By erj.ersjournals.com Published On :: 2020-05-07T01:15:55-07:00 We wish to thank J. Britton and co-workers for responding to our editorial and giving us an opportunity to clarify our position as well as correct a few misunderstandings. We definitely share the same goal, which is to relieve Europe and the rest of the world from the terrible results of the tobacco epidemic. We also do not "blankly oppose e-cigarettes"; however, we strongly advocate against a harm reduction strategy including e-cigarettes as well as heated tobacco products [1]. As clinicians we all see reluctant smokers where e-cigarettes can be tried as a last resort for getting off cigarette smoking, but that is of little relevance for a general harm reduction strategy. We also agree that the UK has achieved a lot in the area of smoking cessation but would argue that this has been achieved by impressive tobacco control, not by the use of e-cigarettes, and that a country such as Australia, which has banned nicotine-containing e-cigarettes, has achieved similar results. Full Article
ac A rational approach to e-cigarettes: challenging ERS policy on tobacco harm reduction By erj.ersjournals.com Published On :: 2020-05-07T01:15:55-07:00 The respiratory community is united in its desire to reduce and eliminate the harm caused by tobacco smoking, which is at present on course to kill one billion people in the 21st century. The stated policy of the European Respiratory Society is to strive "constantly to promote strong and evidence-based policies to reduce the burden of tobacco related diseases". In our view, the recent ERS Tobacco Control Committee statement on tobacco harm reduction [1], though well-intentioned, appears to be based on a number of false premises and draws its conclusions from a partial account of available data. It also presents a false dichotomy between the provision of "conventional" tobacco control and harm reduction approaches. We therefore respond, in turn, to the seven arguments presented against the adoption of harm reduction in the Committee's statement. Full Article
ac Therapeutic drug monitoring using saliva as matrix: an opportunity for linezolid, but challenge for moxifloxacin By erj.ersjournals.com Published On :: 2020-05-07T01:15:54-07:00 The World Health Organization (WHO) has listed moxifloxacin and linezolid among the preferred "group A" drugs in the treatment of multidrug-resistant (MDR)-tuberculosis (TB) [1]. Therapeutic drug monitoring (TDM) could potentially optimise MDR-TB therapy, since moxifloxacin and linezolid show large pharmacokinetic variability [1–4]. TDM of moxifloxacin focuses on identifying patients with low drug exposure who are at risk of treatment failure and acquired fluoroquinolone resistance [5, 6]. Alternatively, TDM of linezolid strives to reduce toxicity while ensuring an adequate drug exposure because of its narrow therapeutic index [1, 3, 7]. Full Article
ac Immediate reactions with glatiramer acetate: Diagnosis of allergy and desensitization protocols By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Purpose of review Diverse adverse events have been associated with administration of glatiramer acetate (GA), mainly local reactions at the injection site. Other, less frequent generalized reactions include isolated postinjection reactions and anaphylaxis, which may lead to discontinuation of GA. Recent findings Close collaboration between the allergy and neurology departments is needed to study adverse reactions to GA. The allergy study should include a detailed history and skin prick and intradermal tests with GA and, if possible, determination of specific IgE levels. Furthermore, the implication of other drugs should be ruled out. Summary An accurate diagnosis of reactions to GA is essential if we are to confirm or rule out allergy to GA. When an allergy diagnosis is confirmed or firmly suspected based on clinical evidence, desensitization protocols are increasingly seen as safe methods for reintroduction of GA. Full Article
ac Worldwide survey of neurologists on approach to autoimmune encephalitis By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Objective To explore practice differences in the diagnosis and management of autoimmune encephalitis (AE), which is complicated by issues with sensitivity/specificity of antibody testing, nonspecific MRI/EEG/CSF findings, and competing differential diagnoses. Methods We used a worldwide electronic survey with practice-related demographic questions and clinical questions about 2 cases: (1) a 20-year-old woman with a neuropsychiatric presentation strongly suspicious of AE and (2) a 40-year-old man with new temporal lobe seizures and cognitive impairment. Responses among different groups were compared using multivariable logistic regression. Results We received 1,333 responses from 94 countries; 12.0% identified as neuroimmunologists. Case 1: those treating >5 AE cases per year were more likely to send antibodies in both serum and CSF (adjusted odds ratio [aOR] vs 0 per year: 3.29, 95% CI 1.31–8.28, p = 0.011), pursue empiric immunotherapy (aOR: 2.42, 95% CI 1.33–4.40, p = 0.004), and continue immunotherapy despite no response and negative antibodies at 2 weeks (aOR: 1.65, 95% CI 1.02–2.69, p = 0.043). Case 2: neuroimmunologists were more likely to send antibodies in both serum and CSF (aOR: 1.80, 95% CI 1.12–2.90, p = 0.015). Those seeing >5 AE cases per year (aOR: 1.86, 95% CI 1.22–2.86, p = 0.004) were more likely to start immunotherapy without waiting for antibody results. Conclusions Our results highlight the heterogeneous management of AE. Neuroimmunologists and those treating more AE cases generally take a more proactive approach to testing and immunotherapy than peers. Results highlight the need for higher-quality cohorts and trials to guide empiric immunotherapy, and evidence-based guidelines aimed at both experts and nonexperts. Because the average AE patient is unlikely to be first seen by a neuroimmunologist, ensuring greater uniformity in our approach to suspected cases is essential to ensure that patients are appropriately managed. Full Article
ac Factors associated with 30-day readmission for patients hospitalized for seizures By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Background We sought to determine the cumulative incidence of readmissions after a seizure-related hospitalization and identify risk factors and readmission diagnoses. Methods We performed a retrospective cohort study of adult patients hospitalized with a primary discharge diagnosis of seizure (International Classification of Diseases, Ninth Edition, Clinical Modification codes 345.xx and 780.3x) using the State Inpatient Databases across 11 states from 2009 to 2012. Hospital and community characteristics were obtained from the American Hospital Association and Robert Wood Johnson Foundation. We performed logistic regressions to explore effects of patient, hospital, and community factors on readmissions within 30 days of discharge. Results Of 98,712 patients, 13,929 (14%) were readmitted within 30 days. Reasons for readmission included epilepsy/convulsions (30% of readmitted patients), mood disorders (5%), schizophrenia (4%), and septicemia (4%). The strongest predictors of readmission were diagnoses of CNS tumor (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.9–2.4) or psychosis (OR 1.8, 95% CI 1.7–1.8), urgent index admission (OR 2.0, 95% CI 1.8–2.2), transfer to nonacute facilities (OR 1.7, 95% CI 1.6–1.8), long length of stay (OR 1.7, 95% CI 1.6–1.8), and for-profit hospitals (OR 1.7, 95% CI 1.6–1.8). Our main model's c-statistic was 0.66. Predictors of readmission for status epilepticus included index admission for status epilepticus (OR 3.5, 95% CI 2.6–4.7), low hospital epilepsy volume (OR 0.4, 95% CI 0.3–0.7), and rural hospitals (OR 4.8, 95% CI 2.1–10.9). Conclusion Readmission is common after hospitalization for seizures. Prevention strategies should focus on recurrent seizures, the most common readmission diagnosis. Many factors were associated with readmission, although readmissions remain challenging to predict. Full Article
ac Cerebral venous thrombosis: Associations between disease severity and cardiac markers By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Background Plasma cardiac troponin (cTn) elevation occurs in acute ischemic stroke and intracranial hemorrhage and can suggest a poor prognosis. Because acute cerebral venous thrombosis (CVT) might lead to venous stasis, which could result in cardiac stress, it is important to evaluate whether cTn elevation occurs in patients with CVT. Methods Inpatients at Johns Hopkins Hospital from 2005 to 2015 meeting the following criteria were included: CVT (ICD-9 codes with radiologic confirmation) and available admission electrocardiogram (ECG) and cTn level. In regression models, presence of ECG abnormalities and cTn elevation (>0.06 ng/mL) were evaluated as dependent variables in separate models, with location and severity of CVT involvement as independent variables, adjusted for age, sex, and hypertension. Results Of 81 patients with CVST, 53 (66%) met the inclusion criteria. Participants were, on average, aged 42 years, white (71%), and female (66%). The left transverse sinus was most commonly thrombosed (47%), with 66% having >2 veins thrombosed. Twenty-two (41%) had cTn elevation. Odds of cTn elevation increased per each additional vein thrombosed (adjusted OR 2.79, 95% CI [1.08–7.23]). Of those with deep venous involvement, 37.5% had cTn elevation compared with 4.4% without deep clots (p = 0.02). Venous infarction (n = 15) was associated with a higher mean cTn (0.14 vs 0.02 ng/mL, p = 0.009) and was predictive of a higher cTn in adjusted models (β = 0.15, 95% CI [0.06–0.25]). Conclusions In this single-center cohort study, markers of CVT severity were associated with increased odds of cTn elevation; further investigation is needed to elucidate causality and significance. Full Article
ac Machine learning as a diagnostic decision aid for patients with transient loss of consciousness By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Background Transient loss of consciousness (TLOC) is a common reason for presentation to primary/emergency care; over 90% are because of epilepsy, syncope, or psychogenic non-epileptic seizures (PNES). Misdiagnoses are common, and there are currently no validated decision rules to aid diagnosis and management. We seek to explore the utility of machine-learning techniques to develop a short diagnostic instrument by extracting features with optimal discriminatory values from responses to detailed questionnaires about TLOC manifestations and comorbidities (86 questions to patients, 31 to TLOC witnesses). Methods Multi-center retrospective self- and witness-report questionnaire study in secondary care settings. Feature selection was performed by an iterative algorithm based on random forest analysis. Data were randomly divided in a 2:1 ratio into training and validation sets (163:86 for all data; 208:92 for analysis excluding witness reports). Results Three hundred patients with proven diagnoses (100 each: epilepsy, syncope and PNES) were recruited from epilepsy and syncope services. Two hundred forty-nine completed patient and witness questionnaires: 86 epilepsy (64 female), 84 PNES (61 female), and 79 syncope (59 female). Responses to 36 questions optimally predicted diagnoses. A classifier trained on these features classified 74/86 (86.0% [95% confidence interval 76.9%–92.6%]) of patients correctly in validation (100 [86.7%–100%] syncope, 85.7 [67.3%–96.0%] epilepsy, 75.0 [56.6%–88.5%] PNES). Excluding witness reports, 34 features provided optimal prediction (classifier accuracy of 72/92 [78.3 (68.4%–86.2%)] in validation, 83.8 [68.0%–93.8%] syncope, 81.5 [61.9%–93.7%] epilepsy, 67.9 [47.7%–84.1%] PNES). Conclusions A tool based on patient symptoms/comorbidities and witness reports separates well between syncope and other common causes of TLOC. It can help to differentiate epilepsy and PNES. Validated decision rules may improve diagnostic processes and reduce misdiagnosis rates. Classification of evidence This study provides Class III evidence that for patients with TLOC, patient and witness questionnaires discriminate between syncope, epilepsy and PNES. Full Article
ac Diagnosing spells: Machines or humans? By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 In the current era of technological advances in medicine, public interest seems focused on advances in laboratory testing, imaging, and surgical instrumentation. Modern-day expectations in the diagnostic part of medicine appear to demand answers which are instant, specific, and without ambiguity. This is consistent with the idea of developing the science of medicine. However, many still consider obtaining a diagnosis through a careful and thoughtful history as an example of the art of medicine. Full Article
ac Unusual and important cause of acute neck pain: Longus colli calcific tendinitis By cp.neurology.org Published On :: 2020-04-06T12:45:20-07:00 Early recognition of longus colli calcific tendinitis can prevent unnecessary interventions including antibiotics and surgical procedures. Full Article
ac Nickel Allergic Contact Dermatitis: Identification, Treatment, and Prevention By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Nickel is a ubiquitous metal added to jewelry and metallic substances for its hardening properties and because it is inexpensive. Estimates suggest that at least 1.1 million children in the United States are sensitized to nickel. Nickel allergic contact dermatitis (Ni-ACD) is the most common cutaneous delayed-type hypersensitivity reaction worldwide. The incidence among children tested has almost quadrupled over the past 3 decades. The associated morbidities include itch, discomfort, school absence, and reduced quality of life. In adulthood, individuals with Ni-ACD may have severe disabling hand eczema. The increasing rate of Ni-ACD in children has been postulated to result from early and frequent exposure to metals with high amounts of nickel release (eg, as occurs with ear piercing or with products used daily in childhood such as toys, belt buckles, and electronics). To reduce exposure to metal sources with high nickel release by prolonged and direct contact with human skin, Denmark and the European Union legislated a directive several decades ago with the goal of reducing high nickel release and the incidence of Ni-ACD. Since then, there has been a global reduction in incidence of Ni-ACD in population-based studies of adults and studies of children and young adults being tested for allergic contact dermatitis. These data point to nickel exposure as a trigger for elicitation of Ni-ACD and, further, provide evidence that legislation can have a favorable effect on the economic and medical health of a population. This policy statement reviews the epidemiology, history, and appearances of Ni-ACD. Examples of sources of high nickel release are discussed to highlight how difficult it is to avoid this metal in modern daily lives. Treatments are outlined, and avoidance strategies are presented. Long-term epidemiological interventions are addressed. Advocacy for smarter nickel use is reviewed. The American Academy of Pediatrics supports US legislation that advances safety standards (as modeled by the European Union) that protect children from early and prolonged skin exposure to high–nickel-releasing items. Our final aim for this article is to aid the pediatric community in developing nickel-avoidance strategies on both individual and global levels. Full Article
ac Family Values Means Covering Families: Parents Need to Focus on Parenting, Not Access to Care By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Full Article
ac Adolescent Sexual Health Interventions: Innovation, Efficacy, Cost, and the Urgent Need to Scale By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Full Article
ac Exploring Early Childhood Factors as an Avenue to Address Chronic Peer Victimization By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Full Article
ac Racial and Ethnic Differences in Emergency Department Pain Management of Children With Fractures By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 OBJECTIVES: To test the hypotheses that minority children with long-bone fractures are less likely to (1) receive analgesics, (2) receive opioid analgesics, and (3) achieve pain reduction. METHODS: We performed a 3-year retrospective cross-sectional study of children <18 years old with long-bone fractures using the Pediatric Emergency Care Applied Research Network Registry (7 emergency departments). We performed bivariable and multivariable logistic regression to measure the association between patient race and ethnicity and (1) any analgesic, (2) opioid analgesic, (3) ≥2-point pain score reduction, and (4) optimal pain reduction (ie, to mild or no pain). RESULTS: In 21 069 visits with moderate-to-severe pain, 86.1% received an analgesic and 45.4% received opioids. Of 8533 patients with reassessment of pain, 89.2% experienced ≥2-point reduction in pain score and 62.2% experienced optimal pain reduction. In multivariable analyses, minority children, compared with non-Hispanic (NH) white children, were more likely to receive any analgesics (NH African American: adjusted odds ratio [aOR] 1.72 [95% confidence interval 1.51–1.95]; Hispanic: 1.32 [1.16–1.51]) and achieve ≥2-point reduction in pain (NH African American: 1.42 [1.14–1.76]; Hispanic: 1.38 [1.04–1.83]) but were less likely to receive opioids (NH African American: aOR 0.86 [0.77–0.95]; Hispanic: aOR 0.86 [0.76–0.96]) or achieve optimal pain reduction (NH African American: aOR 0.78 [0.67–0.90]; Hispanic: aOR 0.80 [0.67–0.95]). CONCLUSIONS: There are differences in process and outcome measures by race and ethnicity in the emergency department management of pain among children with long-bone fractures. Although minority children are more likely to receive analgesics and achieve ≥2-point reduction in pain, they are less likely to receive opioids and achieve optimal pain reduction. Full Article
ac Asking for Identification and Retail Tobacco Sales to Minors By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 BACKGROUND AND OBJECTIVES: A previous single-county study found that retail stores usually asked young-looking tobacco customers to show proof-of-age identification, but a large proportion of illegal tobacco sales to minors occurred after the customers had shown identification proving they were too young to purchase tobacco. We sought to investigate these findings on a larger scale. METHODS: We obtained state reports for federal fiscal years 2017 and 2018 from a federal agency that tracks tobacco sales to supervised minors conducting compliance checks in retail stores. We used descriptive and multivariable logistic regression methods to determine (1) how often stores in 17 states requested identifications, (2) what proportion of violations occurred after identification requests, and (3) if violation rates differed when minors were required versus forbidden to carry identification. RESULTS: Stores asked minors for identification in 79.6% (95% confidence interval: 79.3%–80.8%) of compliance checks (N = 17 276). Violations after identification requests constituted 22.8% (95% confidence interval: 20.0%–25.6%; interstate range, 1.7%–66.2%) of all violations and were nearly 3 times as likely when minors were required to carry identification in compliance checks. Violations were 42% more likely when minors asked for a vaping product versus cigarettes. CONCLUSIONS: Stores that sell tobacco to underage customers are more likely to be detected and penalized when youth inspectors carry identification during undercover tobacco sales compliance checks. The new age-21 tobacco sales requirement presents an opportunity to require identifications be carried and address other long-standing weaknesses in compliance-check protocols to help combat the current adolescent vaping epidemic. Full Article
ac ACA Medicaid Expansion and Insurance Coverage Among New Mothers Living in Poverty By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 BACKGROUND: Medicaid plays a critical role during the perinatal period, but pregnancy-related Medicaid eligibility only extends for 60 days post partum. In 2014, the Affordable Care Act’s (ACA’s) Medicaid expansions increased adult Medicaid eligibility to 138% of the federal poverty level in participating states, allowing eligible new mothers to remain covered after pregnancy-related coverage expires. We investigate the impact of ACA Medicaid expansions on insurance coverage among new mothers living in poverty. METHODS: We define new mothers living in poverty as women ages 19 to 44 with incomes below the federal poverty level who report giving birth in the past 12 months. We use 2010–2017 American Community Survey data and a difference-in-differences approach using parental Medicaid-eligibility thresholds to estimate the effect of ACA Medicaid expansions on insurance coverage among poor new mothers. RESULTS: A 100-percentage-point increase in parental Medicaid-eligibility is associated with an 8.8-percentage-point decrease (P < .001) in uninsurance, a 13.2-percentage-point increase (P < .001) in Medicaid coverage, and a 4.4-percentage-point decrease in private or other coverage (P = .001) among poor new mothers. The average increase in Medicaid eligibility is associated with a 28% decrease in uninsurance, a 13% increase in Medicaid coverage, and an 18% decline in private or other insurance among poor new mothers in expansion states. However, in 2017, there were ~142 000 remaining uninsured, poor new mothers. CONCLUSIONS: ACA Medicaid expansions are associated with increased Medicaid coverage and reduced uninsurance among poor new mothers. Opportunities remain for expansion and nonexpansion states to increase insurance coverage among new mothers living in poverty. Full Article
ac Teenage Use of Smartphone Applications for Menstrual Cycle Tracking By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Full Article
ac {alpha}-Lipoic Acid (ALA) Improves Cystine Solubility in Cystinuria: Report of 2 Cases By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Cystinuria is an autosomal recessive disorder characterized by excessive urinary excretion of cystine, resulting in recurrent cystine kidney stones, often presenting in childhood. Current treatment options for cystinuria include dietary and/or fluid measures and potassium citrate to reduce cystine excretion and/or increase solubility. Tiopronin and D-penicillamine are used in refractory cases to bind cystine in urine, albeit with serious side effects. A recent study revealed efficacy of nutritional supplement α-lipoic acid (ALA) treatment in preventing kidney stones in a mouse model of cystinuria. Here, we report 2 pediatric patients (6 and 15 years old) with cystinuria who received regular doses of ALA in addition to conventional therapy with potassium citrate. Both patients tolerated ALA without any adverse effects and had reduced frequency of symptomatic and asymptomatic kidney stones with disappearance of existing kidney stones in 1 patient after 2 months of ALA therapy. ALA treatment markedly improved laboratory markers of cystine solubility in urine with increased cystine capacity (–223 to –1 mg/L in patient 1 and +140 to +272 mg/L in patient 2) and decreased cystine supersaturation (1.7 to 0.88 in patient 1 and 0.64 to 0.48 in patient 2) without any changes in cystine excretion or urine pH. Our findings suggest that ALA improves solubility of cystine in urine and prevents stone formation in patients with cystinuria who do not respond to diet and citrate therapy. Full Article
ac All for One and One Delivery Room Approach for All? By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 Multiple births are increasing in frequency related to advanced maternal age and fertility treatments, and they have an increased risk for congenital anomalies compared to singleton births. However, twins have the same congenital anomalies <15% of the time. Thus, having multiple births with discordant anomalies is a growing challenge for neonatologists. Although external anomalies can often be spotted quickly at delivery or sex differences between multiples can rapidly identify those with internal anomalies described on prenatal ultrasound, we present a case of male multiples, who would optimally receive different initial resuscitation strategies on the basis of the presence or absence of an internal anomaly. The similar size of 4 extremely preterm quadruplets raises concern for whether accurate, immediate identification of 1 neonate with a congenital diaphragmatic hernia will be reliable in the delivery room. Clinicians discuss the ethical considerations of an "all for one" approach to this resuscitation. Full Article
ac Effect of State Immunization Information System Centralized Reminder and Recall on HPV Vaccination Rates By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 BACKGROUND: Although autodialer centralized reminder and recall (C-R/R) from state immunization information systems (IISs) has been shown to raise childhood vaccination rates, its impact on human papillomavirus (HPV) vaccination rates is unclear. METHODS: In a 4-arm pragmatic randomized controlled trial across 2 states, we randomly selected practices representative of the specialty (pediatrics, family medicine, and health center) where children received care. Within each practice, patients 11 to 17.9 years old who had not completed their HPV vaccine series (NY: N = 30 616 in 123 practices; CO: N = 31 502 in 80 practices) were randomly assigned to receive 0, 1, 2, or 3 IIS C-R/R autodialer messages per vaccine dose. We assessed HPV vaccine receipt via the IIS, calculated intervention costs, and compared HPV vaccine series initiation and completion rates across study arms. RESULTS: In New York, HPV vaccine initiation rates ranged from 37.0% to 37.4%, and completion rates were between 29.1% and 30.1%, with no significant differences across study arms. In Colorado, HPV vaccine initiation rates ranged from 31.2% to 33.5% and were slightly higher for 1 reminder compared with none, but vaccine completion rates, ranging from 27.0% to 27.8%, were similar. On adjusted analyses in Colorado, vaccine initiation rates were slightly higher for 1 and 3 C-R/R messages (adjusted risk ratios 1.07 and 1.04, respectively); completion rates were slightly higher for 1 and 3 C-R/R messages (adjusted risk ratios 1.02 and 1.03, respectively). CONCLUSIONS: IIS-based C-R/R for HPV vaccination did not improve HPV vaccination rates in New York and increased vaccination rates slightly in Colorado. Full Article
ac Early Childhood Factors Associated With Peer Victimization Trajectories From 6 to 17 Years of Age By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 OBJECTIVES: To describe (1) the developmental trajectories of peer victimization from 6 to 17 years of age and (2) the early childhood behaviors and family characteristics associated with the trajectories. METHODS: We used data from 1760 children enrolled in the Quebec Longitudinal Study of Child Development, a population-based birth cohort. Participants self-reported peer victimization at ages 6, 7, 8, 10, 12, 13, 15, and 17 years. Participants’ behavior and family characteristics were measured repeatedly between ages 5 months and 5 years. RESULTS: We identified 4 trajectories of peer victimization from 6 to 17 years of age: low (32.9%), moderate-emerging (29.8%), childhood-limited (26.2%), and high-chronic (11.1%). Compared with children in the low peer victimization trajectory, children in the other 3 trajectories were more likely to exhibit externalizing behaviors in early childhood, and those in the high-chronic and moderate-emerging trajectories were more likely to be male. Paternal history of antisocial behavior was associated with moderate-emerging (odds ratio [OR] = 1.54; 95% confidence interval [CI] = 1.09–2.19) and high-chronic (OR = 1.93; 95% CI = 1.25–2.99) relative to low peer victimization. Living in a nonintact family in early childhood was associated with childhood-limited (OR = 1.48; 95% CI = 1.11–1.97) and high-chronic (OR = 1.59; 95% CI = 1.09–2.31) relative to low peer victimization. CONCLUSIONS: Early childhood externalizing behaviors and family vulnerabilities were associated with the development of peer victimization. Some children entered the cascade of persistent peer victimization at the beginning of primary school. Support to these children and their families early in life should be an important component of peer victimization preventive interventions. Full Article
ac Use of Standing Orders for Vaccination Among Pediatricians By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 OBJECTIVES: Standing orders are an effective way to increase vaccination rates, yet little is known about how pediatricians use this strategy for childhood immunizations. We assessed current use of, barriers to using, and factors associated with use of standing orders for vaccination among pediatricians. METHODS: Internet and mail survey from June 2017 to September 2017 among a nationally representative sample of pediatricians. In the principal component analysis of barrier items, we identified 2 factors: physician responsibility and concerns about office processes. A multivariable analysis that included barrier scales and physician and/or practice characteristics was used to identify factors associated with use of standing orders. RESULTS: The response rate was 79% (372 of 471); 59% of respondents reported using standing orders. The most commonly identified barriers among nonusers were concern that patients may mistakenly receive the wrong vaccine (68%), concern that patients prefer to speak with the physician about a vaccine before receiving it (62%), and belief that it is important for the physician to be the person who recommends a vaccine to patients (57%). These 3 items also made up the physician responsibility barrier factor. Respondents with higher physician responsibility scores were less likely to use standing orders (risk ratio: 0.59 [95% confidence interval: 0.53–0.66] per point increase). System-level decision-making about vaccines, suburban or rural location, and lower concerns about office processes scores were each associated with use of standing orders in the bivariate, but not the multivariable, analysis. CONCLUSIONS: Among pediatricians, use of standing orders for vaccination is far from universal. Interventions to increase use of standing orders should address physicians’ attitudinal barriers as well as organizational factors. Full Article
ac E-cigarette Product Characteristics and Subsequent Frequency of Cigarette Smoking By pediatrics.aappublications.org Published On :: 2020-05-01T01:00:46-07:00 BACKGROUND: There is a dearth of evidence regarding the association of use of electronic cigarettes (e-cigarettes) with certain product characteristics and adolescent and young adult risk of unhealthy tobacco use patterns (eg, frequency of combustible cigarette smoking), which is needed to inform the regulation of e-cigarettes. METHODS: Data were collected via an online survey of participants in the Southern California Children’s Health Study from 2015 to 2016 (baseline) and 2016 to 2017 (follow-up) (N = 1312). We evaluated the association of binary categories of 3 nonmutually exclusive characteristics of the e-cigarette used most frequently with the number of cigarettes smoked in the past 30 days at 1-year follow-up. Product characteristics included device (vape pen and/or modifiable electronic cigarette [mod]), use of nicotine in electronic liquid (e-liquid; yes or no), and use for dripping (directly dripping e-liquid onto the device; yes or no). RESULTS: Relative to never e-cigarette users, past-30-day e-cigarette use was associated with greater frequency of past-30-day cigarette smoking at follow-up. Among baseline past-30-day e-cigarette users, participants who used mods (versus vape pens) smoked >6 times as many cigarettes at follow-up (mean: 20.8 vs 1.3 cigarettes; rate ratio = 6.33; 95% confidence interval: 1.64–24.5) after adjustment for sociodemographic characteristics, baseline frequency of cigarette smoking, and number of days of e-cigarette use. After adjustment for device, neither nicotine e-liquid nor dripping were associated with frequency of cigarette smoking. CONCLUSIONS: Baseline mod users (versus vape pen users) smoked more cigarettes in the past 30 days at follow-up. Regulation of e-cigarette device type warrants consideration as a strategy to reduce cigarette smoking among adolescents and young adults who vape. Full Article
ac Space is the Place: Effects of Continuous Spatial Structure on Analysis of Population Genetic Data [Population and Evolutionary Genetics] By www.genetics.org Published On :: 2020-05-05T06:43:41-07:00 Real geography is continuous, but standard models in population genetics are based on discrete, well-mixed populations. As a result, many methods of analyzing genetic data assume that samples are a random draw from a well-mixed population, but are applied to clustered samples from populations that are structured clinally over space. Here, we use simulations of populations living in continuous geography to study the impacts of dispersal and sampling strategy on population genetic summary statistics, demographic inference, and genome-wide association studies (GWAS). We find that most common summary statistics have distributions that differ substantially from those seen in well-mixed populations, especially when Wright’s neighborhood size is < 100 and sampling is spatially clustered. "Stepping-stone" models reproduce some of these effects, but discretizing the landscape introduces artifacts that in some cases are exacerbated at higher resolutions. The combination of low dispersal and clustered sampling causes demographic inference from the site frequency spectrum to infer more turbulent demographic histories, but averaged results across multiple simulations revealed surprisingly little systematic bias. We also show that the combination of spatially autocorrelated environments and limited dispersal causes GWAS to identify spurious signals of genetic association with purely environmentally determined phenotypes, and that this bias is only partially corrected by regressing out principal components of ancestry. Last, we discuss the relevance of our simulation results for inference from genetic variation in real organisms. Full Article
ac Promoter-Proximal Chromatin Domain Insulator Protein BEAF Mediates Local and Long-Range Communication with a Transcription Factor and Directly Activates a Housekeeping Promoter in Drosophila [Gene Expression] By www.genetics.org Published On :: 2020-05-05T06:43:41-07:00 BEAF (Boundary Element-Associated Factor) was originally identified as a Drosophila melanogaster chromatin domain insulator-binding protein, suggesting a role in gene regulation through chromatin organization and dynamics. Genome-wide mapping found that BEAF usually binds near transcription start sites, often of housekeeping genes, suggesting a role in promoter function. This would be a nontraditional role for an insulator-binding protein. To gain insight into molecular mechanisms of BEAF function, we identified interacting proteins using yeast two-hybrid assays. Here, we focus on the transcription factor Serendipity (Sry-). Interactions were confirmed in pull-down experiments using bacterially expressed proteins, by bimolecular fluorescence complementation, and in a genetic assay in transgenic flies. Sry- interacted with promoter-proximal BEAF both when bound to DNA adjacent to BEAF or > 2-kb upstream to activate a reporter gene in transient transfection experiments. The interaction between BEAF and Sry- was detected using both a minimal developmental promoter (y) and a housekeeping promoter (RpS12), while BEAF alone strongly activated the housekeeping promoter. These two functions for BEAF implicate it in playing a direct role in gene regulation at hundreds of BEAF-associated promoters. Full Article
ac Topoisomerases Modulate the Timing of Meiotic DNA Breakage and Chromosome Morphogenesis in Saccharomyces cerevisiae [Genome Integrity and Transmission] By www.genetics.org Published On :: 2020-05-05T06:43:41-07:00 During meiotic prophase, concurrent transcription, recombination, and chromosome synapsis place substantial topological strain on chromosomal DNA, but the role of topoisomerases in this context remains poorly defined. Here, we analyzed the roles of topoisomerases I and II (Top1 and Top2) during meiotic prophase in Saccharomyces cerevisiae. We show that both topoisomerases accumulate primarily in promoter-containing intergenic regions of actively transcribing genes, including many meiotic double-strand break (DSB) hotspots. Despite the comparable binding patterns, top1 and top2 mutations have different effects on meiotic recombination. TOP1 disruption delays DSB induction and shortens the window of DSB accumulation by an unknown mechanism. By contrast, temperature-sensitive top2-1 mutants exhibit a marked delay in meiotic chromosome remodeling and elevated DSB signals on synapsed chromosomes. The problems in chromosome remodeling were linked to altered Top2 binding patterns rather than a loss of Top2 catalytic activity, and stemmed from a defect in recruiting the chromosome remodeler Pch2/TRIP13 to synapsed chromosomes. No chromosomal defects were observed in the absence of TOP1. Our results imply independent roles for Top1 and Top2 in modulating meiotic chromosome structure and recombination. Full Article
ac Machine Learning Techniques for Classifying the Mutagenic Origins of Point Mutations [Methods, Technology, [amp ] Resources] By www.genetics.org Published On :: 2020-05-05T06:43:41-07:00 There is increasing interest in developing diagnostics that discriminate individual mutagenic mechanisms in a range of applications that include identifying population-specific mutagenesis and resolving distinct mutation signatures in cancer samples. Analyses for these applications assume that mutagenic mechanisms have a distinct relationship with neighboring bases that allows them to be distinguished. Direct support for this assumption is limited to a small number of simple cases, e.g., CpG hypermutability. We have evaluated whether the mechanistic origin of a point mutation can be resolved using only sequence context for a more complicated case. We contrasted single nucleotide variants originating from the multitude of mutagenic processes that normally operate in the mouse germline with those induced by the potent mutagen N-ethyl-N-nitrosourea (ENU). The considerable overlap in the mutation spectra of these two samples make this a challenging problem. Employing a new, robust log-linear modeling method, we demonstrate that neighboring bases contain information regarding point mutation direction that differs between the ENU-induced and spontaneous mutation variant classes. A logistic regression classifier exhibited strong performance at discriminating between the different mutation classes. Concordance between the feature set of the best classifier and information content analyses suggest our results can be generalized to other mutation classification problems. We conclude that machine learning can be used to build a practical classification tool to identify the mutation mechanism for individual genetic variants. Software implementing our approach is freely available under an open-source license. Full Article
ac Fear and Foxes: An Educational Primer for Use with "Anterior Pituitary Transcriptome Suggests Differences in ACTH Release in Tame and Aggressive Foxes" [Primer] By www.genetics.org Published On :: 2020-05-05T06:43:41-07:00 The way genes contribute to behavior is complicated. Although there are some single genes with large contributions, most behavioral differences are due to small effects from many interacting genes. This makes it hard to identify the genes that cause behavioral differences. Mutagenesis screens in model organisms, selective breeding experiments in animals, comparisons between related populations with different behaviors, and genome-wide association studies in humans are promising and complementary approaches to understanding the heritable aspects of complex behaviors. To connect genes to behaviors requires measuring behavioral differences, locating correlated genetic changes, determining when, where, and how these candidate genes act, and designing causative confirmatory experiments. This area of research has implications from basic discovery science to human mental health. Full Article
ac Surfactant Protein-A Protects against IL-13-Induced Inflammation in Asthma [MUCOSAL IMMUNOLOGY] By www.jimmunol.org Published On :: 2020-05-04T13:00:28-07:00 Key Points SP-A is a collectin and plays a key role in innate immunity in the lung. SP-A modulates inflammation in airway epithelial cells from patients with asthma. SP-A modulates IL-13–induced inflammation through downstream IL-6/STAT3 signaling. Full Article
ac Serotonin (5-HT) Shapes the Macrophage Gene Profile through the 5-HT2B-Dependent Activation of the Aryl Hydrocarbon Receptor [INNATE IMMUNITY AND INFLAMMATION] By www.jimmunol.org Published On :: 2020-05-04T13:00:28-07:00 Key Points 5-HT2B agonists stimulate AhR transcriptional activation in human macrophages. Serotonin-induced expression of AhR target genes is 5-HT2B dependent in macrophages. Full Article
ac Development of IFN-Stimulated Gene Expression from Embryogenesis through Adulthood, with and without Constitutive MDA5 Pathway Activation [INNATE IMMUNITY AND INFLAMMATION] By www.jimmunol.org Published On :: 2020-05-04T13:00:28-07:00 Key Points The augmented ISG profile of RdRP mice develops largely postnatally. Elevated ISG expression is then maintained through adulthood. The ISG signature in adults requires persistent type I IFN signaling. Full Article
ac Apolipoprotein E Triggers Complement Activation in Joint Synovial Fluid of Rheumatoid Arthritis Patients by Binding C1q [INNATE IMMUNITY AND INFLAMMATION] By www.jimmunol.org Published On :: 2020-05-04T13:00:28-07:00 Key Points ApoE was found in complex with C4d in RA patient SF. Deposited ApoE activates complement whereas ApoE in solution is inhibitory. Posttranslational modifications alter ApoE's capacity to bind FH and C4BP. Full Article
ac Leishmania donovani Subverts Host Immune Response by Epigenetic Reprogramming of Macrophage M(Lipopolysaccharides + IFN-{gamma})/M(IL-10) Polarization [INFECTIOUS DISEASE AND HOST RESPONSE] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points L. donovani induces histone lysine methyltransferases/demethylases in the host. L. donovani–induced epigenetic enzymes induce host M(IL-10) polarization. Knockdown of epigenetic enzymes inhibited parasite multiplication in infected host. Full Article
ac T Follicular Helper Cells Regulate Humoral Response for Host Protection against Intestinal Citrobacter rodentium Infection [INFECTIOUS DISEASE AND HOST RESPONSE] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points Lack of Tfh cells renders the mice susceptible to C. rodentium infection. Tfh cell–dependent protective Abs are essential to control C. rodentium. Tfh cells regulate IgG1 response to C. rodentium infection. Full Article
ac Development and Characterization of an Avirulent Leishmania major Strain [INFECTIOUS DISEASE AND HOST RESPONSE] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points Virulent and avirulent parasites significantly differ in their proteome profiles. Avirulent parasites fail to inhibit CD40 signaling. Avirulent parasite strain is a potential antileishmanial vaccine candidate. Full Article
ac Complexes between C-Reactive Protein and Very Low Density Lipoprotein Delay Bacterial Clearance in Sepsis [INFECTIOUS DISEASE AND HOST RESPONSE] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points Kupffer cells phagocytose both bacteria and CRP–VLDL complexes. High levels of CRP–VLDL complexes delay bacterial clearance. Pch disrupts CRP–VLDL complexes to improve bacterial clearance. Full Article
ac Molecular Drivers of Lymphocyte Organization in Vertebrate Mucosal Surfaces: Revisiting the TNF Superfamily Hypothesis [IMMUNOGENETICS] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points Lymphotoxin axis is not essential for formation of O-MALT in ectotherms and birds. Vertebrate O-MALT structures are enriched in neuroactive ligand/receptor genes. Mammalian PPs and LNs are enriched in genes involved in olfactory transduction. Full Article
ac Serine Phosphorylation of the STAT1 Transactivation Domain Promotes Autoreactive B Cell and Systemic Autoimmunity Development [AUTOIMMUNITY] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points STAT1-pS727 is required for SLE-associated AFC, GC, and autoantibody responses. STAT1-pS727 in B cells promotes autoimmune AFC, GC, and autoantibody responses. STAT1-pS727 is not required for foreign Ag– or gut microbiota–driven responses. Full Article
ac Complement Deficiencies Result in Surrogate Pathways of Complement Activation in Novel Polygenic Lupus-like Models of Kidney Injury [AUTOIMMUNITY] By www.jimmunol.org Published On :: 2020-05-04T13:00:27-07:00 Key Points Novel TM lupus mouse strains develop spontaneous nephritis. In C1q deficiency, kidney complement activation likely occurred via the LP. In C3 deficiency, coagulation cascade contributed to kidney complement activation. Full Article
ac The Factor H-Binding Site of CspZ as a Protective Target against Multistrain, Tick-Transmitted Lyme Disease [Microbial Immunity and Vaccines] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 The spirochete Borrelia burgdorferi sensu lato is the causative agent of Lyme disease (LD). The spirochetes produce the CspZ protein that binds to a complement regulator, factor H (FH). Such binding downregulates activation of host complement to facilitate spirochete evasion of complement killing. However, vaccination with CspZ does not protect against LD infection. In this study, we demonstrated that immunization with CspZ-YA, a CspZ mutant protein with no FH-binding activity, protected mice from infection by several spirochete genotypes introduced via tick feeding. We found that the sera from CspZ-YA-vaccinated mice more efficiently eliminated spirochetes and blocked CspZ FH-binding activity than sera from CspZ-immunized mice. We also found that vaccination with CspZ, but not CspZ-YA, triggered the production of anti-FH antibodies, justifying CspZ-YA as an LD vaccine candidate. The mechanistic and efficacy information derived from this study provides insights into the development of a CspZ-based LD vaccine. Full Article
ac LuxS/AI-2 Quorum Sensing System in Edwardsiella piscicida Promotes Biofilm Formation and Pathogenicity [Bacterial Infections] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 LuxS/AI-2 is an important quorum sensing system which affects the growth, biofilm formation, virulence, and metabolism of bacteria. LuxS is encoded by the luxS gene, but how this gene is associated with a diverse array of physiological activities in Edwardsiella piscicida (E. piscicida) is not known. Here, we constructed an luxS gene mutant strain, the luxS strain, to identify how LuxS/AI-2 affects pathogenicity. The results showed that LuxS was not found in the luxS gene mutant strain, and this gene deletion decreased E. piscicida growth compared to that of the wild-type strain. Meanwhile, the wild-type strain significantly increased penetration and motility in mucin compared to levels with the luxS strain. The 50% lethal dose (LD50) of the E. piscicida luxS strain for zebrafish was significantly higher than that of the wild-type strain, which suggested that the luxS gene deletion could attenuate the strain’s virulence. The AI-2 activities of EIB202 were 56-fold higher than those in the luxS strain, suggesting that the luxS gene promotes AI-2 production. Transcriptome results demonstrated that between cells infected with the luxS strain and those infected with the wild-type strain 46 genes were significantly differentially regulated, which included 34 upregulated genes and 12 downregulated genes. Among these genes, the largest number were closely related to cell immunity and signaling systems. In addition, the biofilm formation ability of EIB202 was significantly higher than that of the luxS strain. The supernatant of EIB202 increased the biofilm formation ability of the luxS strain, which suggested that the luxS gene and its product LuxS enhanced biofilm formation in E. piscicida. All results indicate that the LuxS/AI-2 quorum sensing system in E. piscicida promotes its pathogenicity through increasing a diverse array of physiological activities. Full Article
ac Early Endothelial Activation Precedes Glycocalyx Degradation and Microvascular Dysfunction in Experimentally Induced Plasmodium falciparum and Plasmodium vivax Infection [Host Response and Inflammation] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 Endothelial activation and microvascular dysfunction are key pathogenic processes in severe malaria. We evaluated the early role of these processes in experimentally induced Plasmodium falciparum and P. vivax infection. Participants were enrolled in induced blood-stage malaria clinical trials. Plasma osteoprotegerin, angiopoietin-2, and von Willebrand Factor (vWF) levels were measured as biomarkers of endothelial activation. Microvascular function was assessed using peripheral arterial tonometry and near-infrared spectroscopy, and the endothelial glycocalyx was assessed by sublingual videomicroscopy and measurement of biomarkers of degradation. Forty-five healthy, malaria-naive participants were recruited from 5 studies. Osteoprotegerin and vWF levels increased in participants following inoculation with P. vivax (n = 16) or P. falciparum (n = 15), with the angiopoietin-2 level also increasing in participants following inoculation with P. falciparum. For both species, the most pronounced increase was seen in osteoprotegerin. This was particularly marked in participants inoculated with P. vivax, where the osteoprotegerin level correlated with the levels of parasitemia and the malaria clinical score. There were no changes in measures of endothelial glycocalyx or microvascular function. Plasma biomarkers of endothelial activation increased in early P. falciparum and P. vivax infection and preceded changes in the endothelial glycocalyx or microvascular function. The more pronounced increase in osteoprotegerin suggests that this biomarker may play a role in disease pathogenesis. Full Article
ac Generation and Evaluation of a Glaesserella (Haemophilus) parasuis Capsular Mutant [Bacterial Infections] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 Glaesserella (Haemophilus) parasuis is a commensal bacterium of the upper respiratory tract in pigs and also the causative agent of Glässer’s disease, which causes significant morbidity and mortality in pigs worldwide. Isolates are characterized into 15 serovars by their capsular polysaccharide, which has shown a correlation with isolate pathogenicity. To investigate the role the capsule plays in G. parasuis virulence and host interaction, a capsule mutant of the serovar 5 strain HS069 was generated (HS069cap) through allelic exchange following natural transformation. HS069cap was unable to cause signs of systemic disease during a pig challenge study and had increased sensitivity to complement killing and phagocytosis by alveolar macrophages. Compared with the parent strain, HS069cap produced more robust biofilm and adhered equivalently to 3D4/31 cells; however, it was unable to persistently colonize the nasal cavity of inoculated pigs, with all pigs clearing HS069cap by 5 days postchallenge. Our results indicate the importance of the capsular polysaccharide to G. parasuis virulence as well as nasal colonization in pigs. Full Article
ac Towards Innovative Design and Application of Recombinant Eimeria as a Vaccine Vector [Minireviews] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 Efficient delivery of antigenic cargo to trigger protective immune responses is critical to the success of vaccination. Genetically engineered microorganisms, including virus, bacteria, and protozoa, can be modified to carry and deliver heterologous antigens to the host immune system. The biological vectors can induce a broad range of immune responses and enhance heterologous antigen-specific immunological outcomes. The protozoan genus Eimeria is widespread in domestic animals, causing serious coccidiosis. Eimeria parasites with strong immunogenicity are potent coccidiosis vaccine candidates and offer a valuable model of live vaccines against infectious diseases in animals. Eimeria parasites can also function as a vaccine vector. Herein, we review recent advances in design and application of recombinant Eimeria as a vaccine vector, which has been a topic of ongoing research in our laboratory. By recapitulating the establishment of an Eimeria transfection platform and its application, it will help lay the foundation for the future development of effective parasite-based vaccine delivery vectors and beyond. Full Article
ac Staphylococcus aureus Fibronectin Binding Protein A Mediates Biofilm Development and Infection [Bacterial Infections] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 Implanted medical device-associated infections pose significant health risks, as they are often the result of bacterial biofilm formation. Staphylococcus aureus is a leading cause of biofilm-associated infections which persist due to mechanisms of device surface adhesion, biofilm accumulation, and reprogramming of host innate immune responses. We found that the S. aureus fibronectin binding protein A (FnBPA) is required for normal biofilm development in mammalian serum and that the SaeRS two-component system is required for functional FnBPA activity in serum. Furthermore, serum-developed biofilms deficient in FnBPA were more susceptible to macrophage invasion, and in a model of biofilm-associated implant infection, we found that FnBPA is crucial for the establishment of infection. Together, these findings show that S. aureus FnBPA plays an important role in physical biofilm development and represents a potential therapeutic target for the prevention and treatment of device-associated infections. Full Article
ac The Legionella pneumophila Metaeffector Lpg2505 (MesI) Regulates SidI-Mediated Translation Inhibition and Novel Glycosyl Hydrolase Activity [Molecular Pathogenesis] By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 Legionella pneumophila, the etiological agent of Legionnaires’ disease, employs an arsenal of hundreds of Dot/Icm-translocated effector proteins to facilitate replication within eukaryotic phagocytes. Several effectors, called metaeffectors, function to regulate the activity of other Dot/Icm-translocated effectors during infection. The metaeffector Lpg2505 is essential for L. pneumophila intracellular replication only when its cognate effector, SidI, is present. SidI is a cytotoxic effector that interacts with the host translation factor eEF1A and potently inhibits eukaryotic protein translation by an unknown mechanism. Here, we evaluated the impact of Lpg2505 on SidI-mediated phenotypes and investigated the mechanism of SidI function. We determined that Lpg2505 binds with nanomolar affinity to SidI and suppresses SidI-mediated inhibition of protein translation. SidI binding to eEF1A and Lpg2505 is not mutually exclusive, and the proteins bind distinct regions of SidI. We also discovered that SidI possesses GDP-dependent glycosyl hydrolase activity and that this activity is regulated by Lpg2505. We have therefore renamed Lpg2505 MesI (metaeffector of SidI). This work reveals novel enzymatic activity for SidI and provides insight into how intracellular replication of L. pneumophila is regulated by a metaeffector. Full Article
ac Fluorescence-Reported Allelic Exchange Mutagenesis-Mediated Gene Deletion Indicates a Requirement for Chlamydia trachomatis Tarp during In Vivo Infectivity and Reveals a Specific Role for the C Terminus during Cellular Invasion [Cellular Microbiology: Pat By iai.asm.org Published On :: 2020-04-20T08:00:39-07:00 The translocated actin recruiting phosphoprotein (Tarp) is a multidomain type III secreted effector used by Chlamydia trachomatis. In aggregate, existing data suggest a role of this effector in initiating new infections. As new genetic tools began to emerge to study chlamydial genes in vivo, we speculated as to what degree Tarp function contributes to Chlamydia’s ability to parasitize mammalian host cells. To address this question, we generated a complete tarP deletion mutant using the fluorescence-reported allelic exchange mutagenesis (FRAEM) technique and complemented the mutant in trans with wild-type tarP or mutant tarP alleles engineered to harbor in-frame domain deletions. We provide evidence for the significant role of Tarp in C. trachomatis invasion of host cells. Complementation studies indicate that the C-terminal filamentous actin (F-actin)-binding domains are responsible for Tarp-mediated invasion efficiency. Wild-type C. trachomatis entry into HeLa cells resulted in host cell shape changes, whereas the tarP mutant did not. Finally, using a novel cis complementation approach, C. trachomatis lacking tarP demonstrated significant attenuation in a murine genital tract infection model. Together, these data provide definitive genetic evidence for the critical role of the Tarp F-actin-binding domains in host cell invasion and for the Tarp effector as a bona fide C. trachomatis virulence factor. Full Article