Machine learning applications on neonatal sepsis treatment: a scoping review.

INTRODUCTION: Neonatal sepsis is a major cause of health loss and mortality worldwide. Without proper treatment, neonatal sepsis can quickly develop into multisystem organ failure. However, the signs of neonatal sepsis are non-specific, and treatment is labour-intensive and expensive. Moreover, antimicrobial resistance is a significant threat globally, and it has been reported that over 70% of neonatal bloodstream infections are resistant to first-line antibiotic treatment. Machine learning is a potential tool to aid clinicians in diagnosing infections and in determining the most appropriate empiric antibiotic treatment, as has been demonstrated for adult populations. This review aimed to present the application of machine learning on neonatal sepsis treatment. METHODS: PubMed, Embase, and Scopus were searched for studies published in English focusing on neonatal sepsis, antibiotics, and machine learning. RESULTS: There were 18 studies included in this scoping review. Three studies focused on using machine learning in antibiotic treatment for bloodstream infections, one focused on predicting in-hospital mortality associated with neonatal sepsis, and the remaining studies focused on developing machine learning prediction models to diagnose possible sepsis cases. Gestational age, C-reactive protein levels, and white blood cell count were important predictors to diagnose neonatal sepsis. Age, weight, and days from hospital admission to blood sample taken were important to predict antibiotic-resistant infections. The best-performing machine learning models were random forest and neural networks. CONCLUSION: Despite the threat antimicrobial resistance poses, there was a lack of studies focusing on the use of machine learning for aiding empirical antibiotic treatment for neonatal sepsis.

Child Witnesses Productively Respond to "How" Questions About Evaluations but Struggle With Other "How" Questions.

Child interviewers are often advised to avoid asking "How" questions, particularly with young children. However, children tend to answer "How" evaluative questions productively (e.g., "How did you feel?"). "How" evaluative questions are phrased as a "How" followed by an auxiliary verb (e.g., "did" or "was"), but so are "How" questions requesting information about method or manner (e.g., "How did he touch you?"), and "How" method/manner questions might be more difficult for children to answer. We examined 458 5- to 17-year-old children questioned about sexual abuse, identified 2485 "How" questions with an auxiliary verb, and classified them as "How" evaluative (n = 886) or "How" method/manner (n = 1599). Across age, children gave more productive answers to "How" evaluative questions than "How" method/manner questions. Although even young children responded appropriately to "How" method/manner questions over 80% of the time, specific types of "How" method/manner questions were particularly difficult, including questions regarding clothing, body positioning, and the nature of touch. Children's difficulties lie in specific combinations of "How" questions and topics, rather than "How" questions in general.

Incidence of Group B Streptococcus Disease in Infants in China: An Updated Systematic Review and Meta-analysis.

New studies of Group B Streptococcus (GBS) in infants <3 months of age in China have been published since our previous systematic review and meta-analysis. Using the same methodology, we updated these estimates and determined a total incidence of 0.41 (95% CI, 0.32-0.51) cases/1000 live births, lower than previously (0.55/1000). New intrapartum antibiotic prophylaxis policies may have played an important role in this reduction.

Experimental dissolution of fossil bone under variable pH conditions.

Fossils exposed at the surface are an integral component of the paleontologic record and provide an archive of past life. However, it is widely known that fossils are not stable indefinitely upon exposure to surface conditions such as physical, chemical, and biological processes, and this last phase of taphonomy is poorly understood. Studies regarding the longevity of fossils subject to weathering, such as acidic precipitation, are absent in the literature. The goal of this study was to experimentally determine vertebrate fossil dissolution rates under variable pH conditions in a controlled laboratory setting. It was hypothesized that fossils would dissolve within acidic solutions and do so at an increasing rate when exposed to increasingly acidic solutions. The experiments were conducted on three fossil vertebrae in triplicate in closed reaction vessels at pH 4, 5, and 6. The fossils were completely submerged for 21 days in a tap water solution with the pH adjusted using 0.1N hydrochloric acid (HCl). Fossil dissolution was quantified by changes to: (1) fossil mass; (2) elemental chemistry of water and fossils with inductively coupled plasma mass spectrometry (ICP-MS); (3) fossil mineralogy with X-ray diffraction (XRD); and (4) histologic structures with thin section analyses. All fossils exhibited mass loss, which increased with decreasing pH conditions, and was greatest under pH 4 (477 to 803 mg loss). The elemental analyses with ICP-MS indicated an increase of both calcium (maximum increase of 315 ppm) and phosphorus (increase of 18 ppm) in aqueous solutions with increasing pH and a loss of those same elements from the fossils (maximum loss of 10 ppm Ca and 6 ppm P). XRD revealed loss of gypsum in all post-dissolution samples. Taken together, the results of ICP-MS and XRD suggest dissolution of the primary mineral phases, including hydroxylapatite, and secondary phases, particularly calcite and gypsum, resulting in an estimated mass loss at pH 4 of 23 to 28 mg per day. Thin section analysis showed degradation of both cortical and trabecular bone in all post-dissolution images, demonstrating physical changes to the fossils as a result of water-rock interactions. These findings constitute the first quantitative analysis of fossil dissolution rates and provide insights into this last stage of taphonomy, addressing a largely understudied potential bias in the vertebrate fossil record.

Effectiveness of Casirivimab-Imdevimab and Sotrovimab During a SARS-CoV-2 Delta Variant Surge: A Cohort Study and Randomized Comparative Effectiveness Trial.

Importance: The effectiveness of monoclonal antibodies (mAbs), casirivimab-imdevimab and sotrovimab, is unknown in patients with mild to moderate COVID-19 caused by the SARS-CoV-2 Delta variant. Objective: To evaluate the effectiveness of mAb against the Delta variant compared with no mAb treatment and to ascertain the comparative effectiveness of casirivimab-imdevimab and sotrovimab. Design, Setting, and Participants: This study comprised 2 parallel studies: (1) a propensity score-matched cohort study of mAb treatment vs no mAb treatment and (2) a randomized comparative effectiveness trial of casirivimab-imdevimab and sotrovimab. The cohort consisted of patients who received mAb treatment at the University of Pittsburgh Medical Center outpatient infusion centers and emergency departments from July 14 to September 29, 2021. Participants were patients with a positive SARS-CoV-2 test result who were eligible to receive mAbs according to emergency use authorization criteria. Exposure: For the trial, patients were randomized to either intravenous casirivimab-imdevimab or sotrovimab according to a system therapeutic interchange policy. Main Outcomes and Measures: For the cohort study, risk ratio (RR) estimates for the primary outcome of hospitalization or death by 28 days were compared between mAb treatment and no mAb treatment using propensity score-matched models. For the comparative effectiveness trial, the primary outcome was hospital-free days (days alive and free of hospitalization) within 28 days after mAb treatment, where patients who died were assigned -1 day in a bayesian cumulative logistic model adjusted for treatment location, age, sex, and time. Inferiority was defined as a 99% posterior probability of an odds ratio (OR) less than 1. Equivalence was defined as a 95% posterior probability that the OR was within a given bound. Results: A total of 3069 patients (1023 received mAb treatment: mean [SD] age, 53.2 [16.4] years; 569 women [56%]; 2046 had no mAb treatment: mean [SD] age, 52.8 [19.5] years; 1157 women [57%]) were included in the prospective cohort study, and 3558 patients (mean [SD] age, 54 [18] years; 1919 women [54%]) were included in the randomized comparative effectiveness trial. In propensity score-matched models, mAb treatment was associated with reduced risk of hospitalization or death (RR, 0.40; 95% CI, 0.28-0.57) compared with no treatment. Both casirivimab-imdevimab (RR, 0.31; 95% CI, 0.20-0.50) and sotrovimab (RR, 0.60; 95% CI, 0.37-1.00) were associated with reduced hospitalization or death compared with no mAb treatment. In the clinical trial, 2454 patients were randomized to receive casirivimab-imdevimab and 1104 patients were randomized to receive sotrovimab. The median (IQR) hospital-free days were 28 (28-28) for both mAb treatments, the 28-day mortality rate was less than 1% (n = 12) for casirivimab-imdevimab and less than 1% (n = 7) for sotrovimab, and the hospitalization rate by day 28 was 12% (n = 291) for casirivimab-imdevimab and 13% (n = 140) for sotrovimab. Compared with patients who received casirivimab-imdevimab, those who received sotrovimab had a median adjusted OR for hospital-free days of 0.88 (95% credible interval, 0.70-1.11). This OR yielded 86% probability of inferiority for sotrovimab vs casirivimab-imdevimab and 79% probability of equivalence. Conclusions and Relevance: In this propensity score-matched cohort study and randomized comparative effectiveness trial, the effectiveness of casirivimab-imdevimab and sotrovimab against the Delta variant was similar, although the prespecified criteria for statistical inferiority or equivalence were not met. Both mAb treatments were associated with a reduced risk of hospitalization or death in nonhospitalized patients with mild to moderate COVID-19 caused by the Delta variant. Trial Registration: ClinicalTrials.gov Identifier: NCT04790786.

The comparative effectiveness of COVID-19 monoclonal antibodies: A learning health system randomized clinical trial.

BACKGROUND: Monoclonal antibodies (mAb) that neutralize SARS-CoV-2 decrease hospitalization and death compared to placebo in patients with mild to moderate COVID-19; however, comparative effectiveness is unknown. We report the comparative effectiveness of bamlanivimab, bamlanivimab-etesevimab, and casirivimab-imdevimab. METHODS: A learning health system platform trial in a U.S. health system enrolled patients meeting mAb Emergency Use Authorization criteria. An electronic health record-embedded application linked local mAb inventory to patient encounters and provided random mAb allocation. Primary outcome was hospital-free days to day 28. Primary analysis was a Bayesian model adjusting for treatment location, age, sex, and time. Inferiority was defined as 99% posterior probability of an odds ratio < 1. Equivalence was defined as 95% posterior probability the odds ratio is within a given bound. FINDINGS: Between March 10 and June 25, 2021, 1935 patients received treatment. Median hospital-free days were 28 (IQR 28, 28) for each mAb. Mortality was 0.8% (1/128), 0.8% (7/885), and 0.7% (6/922) for bamlanivimab, bamlanivimab-etesevimab, and casirivimab-imdevimab, respectively. Relative to casirivimab-imdevimab (n = 922), median adjusted odds ratios were 0.58 (95% credible interval [CI] 0.30-1.16) and 0.94 (95% CI 0.72-1.24) for bamlanivimab (n = 128) and bamlanivimab-etesevimab (n = 885), respectively. These odds ratios yielded 91% and 94% probabilities of inferiority of bamlanivimab versus bamlanivimab-etesevimab and casirivimab-imdevimab, and an 86% probability of equivalence between bamlanivimab-etesevimab and casirivimab-imdevimab. INTERPRETATION: Among patients with mild to moderate COVID-19, bamlanivimab-etesevimab or casirivimab-imdevimab treatment resulted in 86% probability of equivalence. No treatment met prespecified criteria for statistical equivalence. Median hospital-free days to day 28 were 28 (IQR 28, 28) for each mAb. FUNDING AND REGISTRATION: This work received no external funding. The U.S. government provided the reported mAb. This trial is registered at ClinicalTrials.gov, NCT04790786.

Imprecision About Body Mechanics When Child Witnesses Are Questioned About Sexual Abuse.

In child sexual abuse cases, a central part of the child's testimony is their description of the abuse episode. However, it is often difficult for children to describe the body mechanics of abuse, and miscommunications are likely to occur. In the present study, we examined questions about the mechanics of abuse in trial transcripts (N = 63) to identify sources of miscommunication (N = 130) between attorneys and children (5-12 years old, M age at trial = 9.44, SD = 1.97). We found that both attorneys and children used imprecise language, which led to miscommunication. Specifically, the imprecise use of sexual terminology and the word "touch," polarity items, broad open-ended questions, anaphora and elliptical questions, and "how" questions led to imprecision in attorneys' questions. Imprecise attorney questions often elicited underinformative answers from children, including misinterpretations of the grain size (i.e., level of detail) requested. In response to these underinformative answers, attorneys at times asked highly focused and leading questions, which led to further miscommunications. Implications and recommendations for future research on how best to elicit details about the mechanics of abuse from children are discussed.

Did Your Mom Help You Remember?: An Examination of Attorneys' Subtle Questioning About Suggestive Influence to Children Testifying About Child Sexual Abuse.

Researchers studying children's reports of sexual abuse have focused on how questioners overtly assess coaching and truthfulness (e.g., "Did someone tell you what to say?"). Yet attorneys, and defense attorneys, in particular, may be motivated to ask about suggestive influence and truthfulness in subtle ways, such as with implied meaning (e.g., "Did your mom help you remember?"). Such questions may be particularly challenging for children, who may interpret statements literally, misunderstanding the suggested meaning. The purpose of this study was to examine and categorize how attorneys' ask about suggestive influence and truthfulness. We wanted to learn how attorneys subtly accuse suggestive influence, and how frequently this occurred. We hypothesized that questions indirectly accusing suggestive influence would be common, and that defense attorneys would ask more subtle questions, and fewer overt questions, than prosecutors. We examined 7,103 lines of questioning asked by prosecutors and defense attorneys to 64 children testifying about alleged child sexual abuse. We found that 9% of all attorneys' lines of questioning asked about suggestive influence or truthfulness. The majority (66%) of these were indirect accusations. Indirect accusations of suggestive influence spanned a range of subtleties and topics, including addressing conversational influences (e.g., coaching), incidental influences (e.g., witnessing abuse), and others. We also found defense attorneys were less likely than prosecutors to ask about suggestive influence and truthfulness overtly. We conclude that attorneys commonly ask about suggestive influence and truthfulness in subtle ways that developing children may struggle to understand, and which may result in affirmations of influence, even when allegations are true.

Launching a comparative effectiveness adaptive platform trial of monoclonal antibodies for COVID-19 in 21 days.

Outpatient treatments that limit progression to severe coronavirus disease 2019 (COVID-19) are of vital importance to optimise patient outcomes and public health. Monoclonal antibodies (mAb) demonstrated ability to decrease hospitalizations in randomized, clinical trials. However, there are many barriers to mAb treatment such as patient access and clinician education. There are no data comparing efficacy or safety of available mAbs. We sought to rapidly launch an adaptive platform trial with the goals of enhancing access to treatment, regardless of geography and socioeconomic status, and evaluating comparative efficacy and safety of available mAbs. Within 21 days from idea genesis, we allocated mAb treatment to all patients within the context of this clinical trial. Within 2 months, we closed the gap of the likelihood of receiving mAb, conditional on background positivity rate, between Black and White patients (Black patients 0.238; White patients 0.241). We describe trial infrastructure, lessons learned, and future directions for a culture of learning while doing.

Impact of Bamlanivimab Monoclonal Antibody Treatment on Hospitalization and Mortality Among Nonhospitalized Adults With Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

BACKGROUND: Monoclonal antibody treatment may prevent complications of coronavirus disease 2019 (COVID-19). We sought to quantify the impact of bamlanivimab monoclonal antibody monotherapy on hospitalization and mortality among outpatients at high risk of COVID-19 complications. METHODS: In this observational study we compared outpatients who received bamlanivimab monoclonal antibody from December 9, 2020 to March 3, 2021 to nontreated patients with a positive polymerase chain reaction or antigen test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the same period who were eligible for monoclonal antibody treatment. The primary outcome was 28-day hospitalization or all-cause mortality, and the secondary outcome was hospitalization or emergency department visit without hospitalization. The risk-adjusted odds of study outcomes comparing bamlanivimab treated and untreated patients was determined using 1:5 propensity matching and multivariable logistic regression. RESULTS: Among 232 patients receiving bamlanivimab matched with 1160 comparator patients, the mean age was 67 years, 56% were female, and 196 (14%) of patients experienced hospitalization or mortality. After adjustment for propensity to receive treatment, bamlanivimab treatment was associated with a significantly reduced risk-adjusted odds of hospitalization or mortality within 28 days (odds ratio [OR], 0.40; 95% confidence interval [95% CI], 0.24-0.69; P < .001). Bamlanivimab treatment was also associated with a significantly lower risk adjusted odds of hospitalization or emergency department visit without hospitalization (OR, 0.54; 95% CI, 0.35-0.82; P = .004). The results were most strongly associated with patients age 65 years and older. CONCLUSIONS: Bamlanivimab monoclonal antibody monotherapy was associated with reduced hospitalizations and mortality within 28 days among outpatients with mild to moderate COVID-19.Use of bamlanivimab monotherapy for outpatients with mild to moderate COVID-19 infection was associated with reductions in hospitalizations and mortality within 28 days. Benefit was strongest in those age 65 years or older.

The UPMC OPTIMISE-C19 (OPtimizing Treatment and Impact of Monoclonal antIbodieS through Evaluation for COVID-19) trial: a structured summary of a study protocol for an open-label, pragmatic, comparative effectiveness platform trial with response-adaptive randomization.

OBJECTIVES: The primary objective is to evaluate the comparative effectiveness of COVID-19 specific monoclonal antibodies (mABs) with US Food and Drug Administration (FDA) Emergency Use Authorization (EUA), alongside UPMC Health System efforts to increase patient access to these mABs. TRIAL DESIGN: Open-label, pragmatic, comparative effectiveness platform trial with response-adaptive randomization PARTICIPANTS: We will evaluate patients who meet the eligibility criteria stipulated by the COVID-19 mAB EUAs who receive mABs within the UPMC Health System, including infusion centers and emergency departments. EUA eligibility criteria include patients with mild to moderate COVID-19, <10 days of symptoms, and who are at high risk for progressing to severe COVID-19 and/or hospitalization (elderly, obese, and/or with specific comorbidities). The EUA criteria exclude patients who require oxygen for the treatment of COVID-19 and patients already hospitalized for the treatment of COVID-19. We will use data collected for routine clinical care, including data entered into the electronic medical record and from follow-up calls. INTERVENTION AND COMPARATOR: The interventions are the COVID-19 specific mABs authorized by the EUAs. All aspects of mAB treatment, including eligibility criteria, dosing, and post-infusion monitoring, are as per the EUAs. As a comparative effectiveness trial, all patients receive mAB treatment, and the interventions are compared against each other. When U.S. government mAB policies change (e.g., FDA grants or revokes EUAs), UPMC Health System policies and the evaluated mAB interventions will accordingly change. From November 2020 to February 2021, FDA issued EUAs for three mAB treatments (bamlanivimab; bamlanivimab and etesevimab; and casirivimab and imdevimab), and at trial launch on March 10, 2021 we evaluated all three. Due to a sustained increase in SARS-CoV-2 variants in the United States resistant to bamlanivimab administered alone, on March 24, 2021 the U.S. Government halted distribution of bamlanivimab alone, and UPMC accordingly halted bamlanivimab monotherapy on March 31, 2021. On April 16, 2021, FDA revoked the EUA for bamlanivimab monotherapy. At the time of manuscript submission, we are therefore evaluating the two mAB treatments authorized by EUAs (bamlanivimab and etesevimab; and casirivimab and imdevimab). MAIN OUTCOMES: The primary outcome is total hospital free days (HFD) at 28 days after mAB administration, calculated as 28 minus the number of days during the index stay (if applicable - e.g., for patients admitted to hospital after mAB administration in the emergency department) minus the number of days readmitted during the 28 days after treatment. This composite endpoint captures the number of days from the day of mAB administration to the 28 days thereafter, during which the patient is alive and free of hospitalization. Death within 28 days is recorded as -1 HFD, as the worst outcome. RANDOMISATION: We will start with equal allocation. Due to uncertainty in sample size, we will use a Bayesian adaptive design and response adaptive randomization to ensure ability to provide statistical inference despite variable sample size. When mABs are ordered by UPMC physicians as a generic referral order, the order is filled by UPMC pharmacy via therapeutic interchange. OPTIMISE-C19 provides the therapeutic interchange via random allocation. Infusion center operations teams and pharmacists use a mAB assignment application embedded in the electronic medical record to determine the random allocation. BLINDING (MASKING): This trial is open-label. However, outcome assessors conducting follow-up calls at day 28 are blinded to mAB assignment, and investigators are blinded to by-mAB aggregate outcome data until a statistical platform trial conclusion is reached. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): Sample size will be determined by case volume throughout the course of the pandemic, supply of FDA authorized mABs, and by that needed to reach a platform trial conclusion of inferiority, superiority, or futility of a given mAB. The trial will continue as long as more than one mAB type is available under EUA, and their comparative effectiveness is uncertain. TRIAL STATUS: Protocol Version 1.0, February 24, 2021. Recruitment began March 10, 2021 and is ongoing at the time of manuscript submission. The estimated recruitment end date is February 22, 2022, though the final end date is dependent on how the pandemic evolves, mAB availability, and when final platform trial conclusions are reached. As noted above, due to U.S. Government decisions, UPMC Health System halted bamlanivimab monotherapy on March 31, 2021. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04790786 . Registered March 10, 2021 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Assessing Children's Credibility in Courtroom Investigations of Alleged Child Sexual Abuse: Suggestibility, Plausibility, and Consistency.

As children's testimonies of child sexual abuse (CSA) often lack concrete evidence to corroborate a child's claims, attorneys devote a substantial amount of time to establishing a child as credible during the course of a trial. Examining 134 CSA victim testimonies for children aged 5-17 (M = 12.48, SD = 3.34; 90% female), we explored how attorneys assess child credibility through specifically targeting children's suggestibility/honesty, plausibility, and consistency. Results revealed that while prosecutors examine plausibility more often to establish credibility, defense attorneys focus their assessments on suggestibility/honesty and potential inconsistency. However, both attorneys asked many more questions about children's consistency than any other area of potential credibility. Furthermore, while prosecutors ask proportionally more credibility-challenging questions of older children, the defense do not. These results suggest that prosecutors may be missing an opportunity to establish children as honest and consistent and elucidate a need to train attorneys on the implications of children's inconsistencies, suggestibility, and plausible abuse dynamics.

The multidimensional nature of social support and engagement in contributing to adjustment following spousal loss.

Objectives: Spousal loss is a significant life event that can negatively affect multiple facets of mental and physical health. Social support and engagement are generally found to improve adjustment following adversity, but much less is known regarding which facet of social support and engagement is most predictive of adjustment following spousal loss. This study examined changes in mental health and well-being following spousal loss and which facets of social support and engagement are associated with positive adjustment following spousal loss.Method: Latent growth curve modeling was applied to longitudinal data from 265 individuals who became widowed from the Changing Lives of Older Couples Study to examine: (1) adjustment following spousal loss in depressive symptoms, anxiety and well-being and (2) whether different facets of social support and engagement predict positive adjustment.Results: Depressive symptoms increased following spousal loss, whereas anxiety and well-being remained relatively stable before and after spousal loss. Receiving more instrumental support was associated with lower levels of depressive symptoms and anxiety 6-months following spousal loss. Higher levels of emotional support from one's spouse at baseline was associated with more depressive symptoms and anxiety 6-months following spousal loss.Conclusion: Instrumental support received was the most beneficial facet of social support and engagement. The discussion focuses on how these findings fit into the larger literature of the ways through which social support and engagement lead to adjustment following adversity.

Family-Centered Care During Constraint-Induced Therapy After Chronic Stroke: A Feasibility Study.

PURPOSE: This feasibility study evaluated a theory-based intervention (CARE-CITE) designed to engage carepartners (CPs) in supporting stroke survivor upper extremity rehabilitation. DESIGN: The study was a one-group design with pre- and posttest and 1 month follow-up (N = 7 dyads). METHODS: Feasibility was determined by participant retention, CP and stroke survivor intervention adherence, and CP acceptability of the intervention (exit interview). Measures of CP depressive symptoms, fatigue, and family conflict around stroke recovery and stroke survivor upper extremity function are reported. Data were analyzed using descriptive statistics. FINDINGS: All participants completed the study and adhered to the intervention, and CPs found CARE-CITE helpful. Descriptively, better scores were observed for CP's mental health, family conflict, stroke survivor confidence, and upper extremity tasks performed. CONCLUSION: These results provide initial evidence that CARE-CITE is feasible after chronic stroke and that CPs and stroke survivors may benefit from family-centered care. CLINICAL RELEVANCE: Improving CP skills in supporting rehabilitation activities may improve stroke survivor upper extremity function.

Compensatory hemagglutinin mutations alter antigenic properties of influenza viruses.

Influenza viruses routinely acquire mutations in antigenic sites on the globular head of the hemagglutinin (HA) protein. Since these antigenic sites are near the receptor binding pocket of HA, many antigenic mutations simultaneously alter the receptor binding properties of HA. We previously reported that a K165E mutation in the Sa antigenic site of A/Puerto Rico/8/34 (PR8) HA is associated with secondary neuraminidase (NA) mutations that decrease NA activity. Here, using reverse genetics, we show that the K165E HA mutation dramatically decreases HA binding to sialic acid receptors on cell surfaces. We sequentially passaged reverse-genetics-derived PR8 viruses with the K165E antigenic HA mutation in fertilized chicken eggs, and to our surprise, viruses with secondary NA mutations did not emerge. Instead, viruses with secondary HA mutations emerged in 3 independent passaging experiments, and each of these mutations increased HA binding to sialic acid receptors. Importantly, these compensatory HA mutations were located in the Ca antigenic site and prevented binding of Ca-specific monoclonal antibodies. Taken together, these data indicate that HA antigenic mutations that alter receptor binding avidity can be compensated for by secondary HA or NA mutations. Antigenic diversification of influenza viruses can therefore occur irrespective of direct antibody pressure, since compensatory HA mutations can be located in distinct antibody binding sites.

Single hemagglutinin mutations that alter both antigenicity and receptor binding avidity influence influenza virus antigenic clustering.

The hemagglutination inhibition (HAI) assay is the primary measurement used for identifying antigenically novel influenza virus strains. HAI assays measure the amount of reference sera required to prevent virus binding to red blood cells. Receptor binding avidities of viral strains are not usually taken into account when interpreting these assays. Here, we created antigenic maps of human H3N2 viruses that computationally account for variation in viral receptor binding avidities. These new antigenic maps differ qualitatively from conventional antigenic maps based on HAI measurements alone. We experimentally focused on an antigenic cluster associated with a single N145K hemagglutinin (HA) substitution that occurred between 1992 and 1995. Reverse-genetics experiments demonstrated that the N145K HA mutation increases viral receptor binding avidity. Enzyme-linked immunosorbent assays (ELISA) revealed that the N145K HA mutation does not prevent antibody binding; rather, viruses possessing this mutation escape antisera in HAI assays simply by attaching to cells more efficiently. Unexpectedly, we found an asymmetric antigenic effect of the N145K HA mutation. Once H3N2 viruses acquired K145, an epitope involving amino acid 145 became antigenically dominant. Antisera raised against an H3N2 strain possessing K145 had reduced reactivity to H3N2 strains possessing N145. Thus, individual mutations in HA can influence antigenic groupings of strains by altering receptor binding avidity and by changing the dominance of antibody responses. Our results indicate that it will be important to account for variation in viral receptor binding avidity when performing antigenic analyses in order to identify genuine antigenic differences among influenza virus variants.

Immune history shapes specificity of pandemic H1N1 influenza antibody responses.

Human antibody responses against the 2009 pandemic H1N1 (pH1N1) virus are predominantly directed against conserved epitopes in the stalk and receptor-binding domain of the hemagglutinin (HA) protein. This is in stark contrast to pH1N1 antibody responses generated in ferrets, which are focused on the variable Sa antigenic site of HA. Here, we show that most humans born between 1983 and 1996 elicited pH1N1 antibody responses that are directed against an epitope near the HA receptor-binding domain. Importantly, most individuals born before 1983 or after 1996 did not elicit pH1N1 antibodies to this HA epitope. The HAs of most seasonal H1N1 (sH1N1) viruses that circulated between 1983 and 1996 possess a critical K133 amino acid in this HA epitope, whereas this amino acid is either mutated or deleted in most sH1N1 viruses circulating before 1983 or after 1996. We sequentially infected ferrets with a 1991 sH1N1 virus and then a pH1N1 virus. Sera isolated from these animals were directed against the HA epitope involving amino acid K133. These data suggest that the specificity of pH1N1 antibody responses can be shifted to epitopes near the HA receptor-binding domain after sequential infections with sH1N1 and pH1N1 viruses that share homology in this region.

Strain-dependent effects of acute, chronic, and withdrawal from chronic nicotine on fear conditioning.

The effects of nicotine on cognitive processes such as learning and memory may play an important role in the addictive liability of tobacco. However, it remains unknown whether genetic variability modulates the effects of nicotine on learning and memory. The present study characterized the effects of acute, chronic, and withdrawal from chronic nicotine administration on fear conditioning, somatic signs, and the elevated plus maze in 8 strains of inbred mice. Strain-dependent effects of acute nicotine and nicotine withdrawal on contextual fear conditioning, somatic signs, and the elevated plus maze were observed, but no association between the effects of acute nicotine and nicotine withdrawal on contextual fear conditioning were observed, suggesting that different genetic substrates may mediate these effects. The identification of genetic factors that may alter the effects of nicotine on cognition may lead to more efficacious treatments for nicotine addiction.

Detecting autism spectrum disorder from early intervention charts: methodology and preliminary findings.

Federal laws mandating a "single point of entry" for early intervention (EI) create a potential database for surveillance of early childhood disabilities. This study evaluated EI records for estimating rates of autism spectrum disorder (ASD) using a chart abstraction protocol, with good interrater agreement (k = .86). Sampling 304 EI records yielded a point prevalence of (per 1,000) 8.5 (95% CI: 4.8-10.9) and a cumulative incidence of 7.4 (95% CI: 5.5-12.4). These rates are similar to recent published estimates. Additionally, the male-to-female ratio for autism, and rates of other developmental disorders were found to be consistent with current literature. These results suggest that local systems EI records may provide an excellent resource for ASD surveillance and research.