Proteasome activity is required for reovirus entry into cells.

IMPORTANCE: Due to their limited genetic capacity, viruses are reliant on multiple host systems to replicate successfully. Mammalian orthoreovirus (reovirus) is commonly used as a model system for understanding host-virus interactions. In this study, we identify that the proteasome system, which is critical for cellular protein turnover, affects reovirus entry. Inhibition of the proteasome using a chemical inhibitor blocks reovirus uncoating. Blocking these events reduces subsequent replication of the virus. This work identifies that additional host factors control reovirus entry.

The Reovirus σ3 Protein Inhibits NF-κB-Dependent Antiviral Signaling.

Viral antagonism of innate immune pathways is a common mechanism by which viruses evade immune surveillance. Infection of host cells with reovirus leads to the blockade of NF-κB, a key transcriptional regulator of the hosts' innate immune response. One mechanism by which reovirus infection results in inhibition of NF-κB is through a diminishment in levels of upstream activators, IKKß and NEMO. Here, we demonstrate a second, distinct mechanism by which reovirus blocks NF-κB. We report that expression of a single viral protein, σ3, is sufficient to inhibit expression of NF-κB target genes. Further, σ3-mediated blockade of NF-κB occurs without changes to IκB kinase (IKK) levels or activity. Among NF-κB targets, the expression of type I interferon is significantly diminished by σ3 expression. Expression of NF-κB target genes varies following infection with closely related reovirus strains. Our genetic analysis identifies that these differences are controlled by polymorphisms in the amino acid sequence of σ3. This work identifies a new role for reovirus σ3 as a viral antagonist of NF-κB-dependent antiviral pathways. IMPORTANCE Host cells mount a response to curb virus replication in infected cells and prevent spread of virus to neighboring, as yet uninfected, cells. The NF-κB family of proteins is important for the cell to mediate this response. In this study, we show that a single protein, σ3, produced by mammalian reovirus, impairs the function of NF-κB. We demonstrate that by blocking NF-κB, σ3 diminishes the hosts' response to infection to promote viral replication. This work identifies a second, previously unknown, mechanism by which reovirus blocks this aspect of the host cell response.

Defining Clinical and Immunological Predictors of Poor Immune Responses to COVID-19 mRNA Vaccines in Patients with Primary Antibody Deficiency.

Immune responses to coronavirus disease 2019 (COVID-19) mRNA vaccines in primary antibody deficiencies (PADs) are largely unknown. We investigated antibody and CD4+ T-cell responses specific for SARS-CoV-2 spike protein (S) before and after vaccination and associations between vaccine response and patients' clinical and immunological characteristics in PADs. The PAD cohort consisted of common variable immune deficiency (CVID) and other PADs, not meeting the criteria for CVID diagnosis (oPADs). Anti-S IgG, IgA, and IgG subclasses 1 and 3 increased after vaccination and correlated with neutralization activity in HCs and patients with oPADs. However, 42% of CVID patients developed such responses after the 2nd dose. A similar pattern was also observed with S-specific CD4+ T-cells as determined by OX40 and 4-1BB expression. Patients with poor anti-S IgG response had significantly lower levels of baseline IgG, IgA, CD19+ B-cells, switched memory B-cells, naïve CD8+ T-cells, and a higher frequency of EM CD8+ T-cells and autoimmunity compared to patients with adequate anti-S IgG responses. Patients with oPADs can develop humoral and cellular immune responses to vaccines similar to HCs. However, a subset of CVID patients exhibit impairment in developing such responses, which can be predicted by the baseline immune profile and history of autoimmunity.

Loss of IKK Subunits Limits NF-κB Signaling in Reovirus-Infected Cells.

Viruses commonly antagonize innate immune pathways that are primarily driven by nuclear factor kappa B (NF-κB), interferon regulatory factor (IRF), and the signal transducer and activator of transcription proteins (STAT) family of transcription factors. Such a strategy allows viruses to evade immune surveillance and maximize their replication. Using an unbiased transcriptome sequencing (RNA-seq)-based approach to measure gene expression induced by transfected viral genomic RNA (vgRNA) and reovirus infection, we discovered that mammalian reovirus inhibits host cell innate immune signaling. We found that, while vgRNA and reovirus infection both induce a similar IRF-dependent gene expression program, gene expression driven by the NF-κB family of transcription factors is lower in infected cells. Potent agonists of NF-κB such as tumor necrosis factor alpha (TNF-α) and vgRNA failed to induce NF-κB-dependent gene expression in infected cells. We demonstrate that NF-κB signaling is blocked due to loss of critical members of the inhibitor of kappa B kinase (IKK) complex, NF-κB essential modifier (NEMO), and IKKß. The loss of the IKK complex components prevents nuclear translocation and phosphorylation of NF-κB, thereby preventing gene expression. Our study demonstrates that reovirus infection selectively blocks NF-κB, likely to counteract its antiviral effects and promote efficient viral replication.IMPORTANCE Host cells mount a response to curb virus replication in infected cells and prevent spread of virus to neighboring, as yet uninfected, cells. The NF-κB family of proteins is important for the cell to mediate this response. In this study, we show that in cells infected with mammalian reovirus, NF-κB is inactive. Further, we demonstrate that NF-κB is rendered inactive because virus infection results in reduced levels of upstream intermediaries (called IKKs) that are needed for NF-κB function. Based on previous evidence that active NF-κB limits reovirus infection, we conclude that inactivating NF-κB is a viral strategy to produce a cellular environment that is favorable for virus replication.

Cell Killing by Reovirus: Mechanisms and Consequences.

Infection of host cells by mammalian reovirus in culture or in tissues of infected animals results in cell death. Cell death of infected neurons and myocytes contributes to the pathogenesis of reovirus-induced encephalitis and myocarditis in a newborn mouse model. Thus, reovirus-induced cell death has been used to investigate the basis of viral disease. Depending on the cell type, infection of host cells by reovirus results in one of two forms of cell death-apoptosis and necroptosis. In addition to the obvious differences in how these two forms of cell death are executed, the mechanisms by which reovirus infection initiates and transduces signals that lead to each of these types of cell death are distinct. In this review, we discuss how apoptosis and necroptosis are triggered by events at different stages of infection. We also describe how innate immune recognition of reovirus genomic material and type I interferon signaling pathways connect with the core components of the apoptosis and necroptosis machinery. The impact of different cell death mediators on viral pathogenesis and the potential of reovirus as an oncolytic vector are also outlined.

DNA hypomethylation promotes the expression of CASPASE-4 which exacerbates inflammation and amyloid-ß deposition in Alzheimer's disease.

Alzheimer's disease (AD) is the sixth leading cause of death in the USA. It is established that neuroinflammation contributes to the synaptic loss, neuronal death, and symptomatic decline of AD patients. Accumulating evidence suggests a critical role for microglia, innate immune phagocytes of the brain. For instance, microglia release pro-inflammatory products such as IL-1ß which is highly implicated in AD pathobiology. The mechanisms underlying the transition of microglia to proinflammatory promoters of AD remain largely unknown. To address this gap, we performed reduced representation bisulfite sequencing (RRBS) to profile global DNA methylation changes in human AD brains compared to no disease controls. We identified differential DNA methylation of CASPASE-4 (CASP4), which when expressed promotes the generation of IL-1ß and is predominantly expressed in immune cells. DNA upstream of the CASP4 transcription start site was hypomethylated in human AD brains, which was correlated with increased expression of CASP4. Furthermore, microglia from a mouse model of AD (5xFAD) express increased levels of CASP4 compared to wild-type (WT) mice. To study the role of CASP4 in AD, we developed a novel mouse model of AD lacking the mouse ortholog of CASP4 and CASP11, which is encoded by mouse Caspase-4 (5xFAD/Casp4-/-). The expression of CASP11 was associated with increased accumulation of pathologic protein aggregate amyloid-ß (Aß) and increased microglial production of IL-1ß in 5xFAD mice. Utilizing RNA-sequencing, we determined that CASP11 promotes unique transcriptomic phenotypes in 5xFAD mouse brains, including alterations of neuroinflammatory and chemokine signaling pathways. Notably, in vitro, CASP11 promoted generation of IL-1ß from macrophages in response to cytosolic Aß through cleavage of downstream effector Gasdermin D (GSDMD). Therefore, here we unravel the role for CASP11 and GSDMD in the generation of IL-1ß in response to Aß and the progression of pathologic inflammation in AD. Overall, our results demonstrate that overexpression of CASP4 due to differential DNA methylation in AD microglia contributes to the progression of AD pathobiology. Thus, we identify CASP4 as a potential target for immunotherapies for the treatment and prevention of AD.

DNA hypomethylation promotes the expression of CASPASE-4 which exacerbates neuroinflammation and amyloid-ß deposition in Alzheimer's disease The Ohio State University College of Medicine.

Alzheimer's Disease (AD) is the 6th leading cause of death in the US. It is established that neuroinflammation contributes to the synaptic loss, neuronal death, and symptomatic decline of AD patients. Accumulating evidence suggests a critical role for microglia, innate immune phagocytes of the brain. For instance, microglia release proinflammatory products such as IL-1ß which is highly implicated in AD pathobiology. The mechanisms underlying the transition of microglia to proinflammatory promoters of AD remain largely unknown. To address this gap, we performed Reduced Representation Bisulfite Sequencing (RRBS) to profile global DNA methylation changes in human AD brains compared to no disease controls. We identified differential DNA methylation of CASPASE-4 (CASP4), which when expressed, can be involved in generation of IL-1ß and is predominantly expressed in immune cells. DNA upstream of the CASP4 transcription start site was hypomethylated in human AD brains, which was correlated with increased expression of CASP4. Furthermore, microglia from a mouse model of AD (5xFAD) express increased levels of CASP4 compared to wild-type (WT) mice. To study the role of CASP4 in AD, we developed a novel mouse model of AD lacking the mouse ortholog of CASP4, CASP11, which is encoded by mouse Caspase-4 (5xFAD/Casp4-/-). The expression of CASP11 was associated with increased accumulation of pathologic protein aggregate amyloid-ß (Aß) and increased microglial production of IL-1ß in 5xFAD mice. Utilizing RNA sequencing, we determined that CASP11 promotes unique transcriptomic phenotypes in 5xFAD mouse brains, including alterations of neuroinflammatory and chemokine signaling pathways. Notably, in vitro, CASP11 promoted generation of IL-1ß from macrophages in response to cytosolic Aß through cleavage of downstream effector Gasdermin D (G SDMD). We describe a role for CASP11 and GSDMD in the generation of IL-1ß in response to Aß and the progression of pathologic inflammation in AD. Overall, our results demonstrate that overexpression of CASP4 due to differential methylation in AD microglia contributes to the progression of AD pathobiology, thus identifying CASP4 as a potential target for immunotherapies for the treatment of AD.

Pharmacological disruption of mSWI/SNF complex activity restricts SARS-CoV-2 infection.

Identification of host determinants of coronavirus infection informs mechanisms of viral pathogenesis and can provide new drug targets. Here we demonstrate that mammalian SWItch/Sucrose Non-Fermentable (mSWI/SNF) chromatin remodeling complexes, specifically canonical BRG1/BRM-associated factor (cBAF) complexes, promote severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and represent host-directed therapeutic targets. The catalytic activity of SMARCA4 is required for mSWI/SNF-driven chromatin accessibility at the ACE2 locus, ACE2 expression and virus susceptibility. The transcription factors HNF1A/B interact with and recruit mSWI/SNF complexes to ACE2 enhancers, which contain high HNF1A motif density. Notably, small-molecule mSWI/SNF ATPase inhibitors or degraders abrogate angiotensin-converting enzyme 2 (ACE2) expression and confer resistance to SARS-CoV-2 variants and a remdesivir-resistant virus in three cell lines and three primary human cell types, including airway epithelial cells, by up to 5 logs. These data highlight the role of mSWI/SNF complex activities in conferring SARS-CoV-2 susceptibility and identify a potential class of broad-acting antivirals to combat emerging coronaviruses and drug-resistant variants.

Nonoperative Treatment of Posterior Wall Acetabular Fractures After Dynamic Stress Examination Under Anesthesia: Revisited.

OBJECTIVES: Performing an examination under general anesthesia (EUA) using dynamic stress fluoroscopy of patients with posterior wall acetabular fractures has been used as a tool to determine hip stability and the need for surgical intervention. The purpose of this study was to further evaluate the effectiveness of this technique, from a source other than its primary advocates, in patients with posterior wall acetabular fractures less than or equal to 50% who were stable on EUA and treated nonoperatively. DESIGN: Retrospective case series. SETTING: University Level 1 Trauma Center. PARTICIPANTS: Seventeen patients with a posterior wall acetabular fracture stable on EUA treated nonoperatively. INTERVENTION: The patients were treated nonoperatively as guided by an EUA negative for instability. Patient follow-up averaged 30 months (range, 6-64 months). MAIN OUTCOME MEASUREMENTS: Outcome evaluation included the modified Merle d'Aubigné clinical score and the Short Musculoskeletal Function Assessment Questionnaire. Radiographic evaluation for subluxation or arthritis consisted of the 3 standard pelvic radiographs. RESULTS: Radiographic evaluation showed all hips to be congruent with a normal joint space. Sixteen of the 17 patients had radiographic outcomes rated as "excellent"; 1 patient was rated "good." The modified Merle d'Aubigné score (obtained in 12 patients) averaged very good, with only 1 having less than a good (graded as fair) clinical outcome. The Short Musculoskeletal Function Assessment Questionnaire scores (from 11 patients) were not significantly different from normal and were within the normal reported values for all indices and categories. There was no correlation between fracture fragment size and outcome. CONCLUSIONS: This study further supports the contention that a stable hip joint, as determined by EUA, after posterior wall acetabular fracture treated nonoperatively is predictive of continued joint congruity, an excellent radiographic outcome, and good-to-excellent early clinical and functional outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Multiplexed LNP-mRNA vaccination against pathogenic coronavirus species.

Although COVID-19 vaccines have been developed, multiple pathogenic coronavirus species exist, urging on development of multispecies coronavirus vaccines. Here we develop prototype lipid nanoparticle (LNP)-mRNA vaccine candidates against SARS-CoV-2 Delta, SARS-CoV, and MERS-CoV, and we test how multiplexing LNP-mRNAs can induce effective immune responses in animal models. Triplex and duplex LNP-mRNA vaccinations induce antigen-specific antibody responses against SARS-CoV-2, SARS-CoV, and MERS-CoV. Single-cell RNA sequencing profiles the global systemic immune repertoires and respective transcriptome signatures of vaccinated animals, revealing a systemic increase in activated B cells and differential gene expression across major adaptive immune cells. Sequential vaccination shows potent antibody responses against all three species, significantly stronger than simultaneous vaccination in mixture. These data demonstrate the feasibility, antibody responses, and single-cell immune profiles of multispecies coronavirus vaccination. The direct comparison between simultaneous and sequential vaccination offers insights into optimization of vaccination schedules to provide broad and potent antibody immunity against three major pathogenic coronavirus species.

Omicron-specific mRNA vaccination alone and as a heterologous booster against SARS-CoV-2.

The Omicron variant of SARS-CoV-2 recently swept the globe and showed high level of immune evasion. Here, we generate an Omicron-specific lipid nanoparticle (LNP) mRNA vaccine candidate, and test its activity in animals, both alone and as a heterologous booster to WT mRNA vaccine. Our Omicron-specific LNP-mRNA vaccine elicits strong antibody response in vaccination-naïve mice. Mice that received two-dose WT LNP-mRNA show a > 40-fold reduction in neutralization potency against Omicron than WT two weeks post boost, which further reduce to background level after 3 months. The WT or Omicron LNP-mRNA booster increases the waning antibody response of WT LNP-mRNA vaccinated mice against Omicron by 40 fold at two weeks post injection. Interestingly, the heterologous Omicron booster elicits neutralizing titers 10-20 fold higher than the homologous WT booster against Omicron variant, with comparable titers against Delta variant. All three types of vaccination, including Omicron alone, WT booster and Omicron booster, elicit broad binding antibody responses against SARS-CoV-2 WA-1, Beta, Delta variants and SARS-CoV. These data provide direct assessments of an Omicron-specific mRNA vaccination in vivo, both alone and as a heterologous booster to WT mRNA vaccine.

Omicron-specific mRNA vaccination alone and as a heterologous booster against SARS-CoV-2.

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has high transmissibility and recently swept the globe. Due to the extensive number of mutations, this variant has high level of immune evasion, which drastically reduced the efficacy of existing antibodies and vaccines. Thus, it is important to test an Omicron-specific vaccine, evaluate its immune response against Omicron and other variants, and compare its immunogenicity as boosters with existing vaccine designed against the reference wildtype virus (WT). Here, we generated an Omicron-specific lipid nanoparticle (LNP) mRNA vaccine candidate, and tested its activity in animals, both alone and as a heterologous booster to existing WT mRNA vaccine. Our Omicron-specific LNP-mRNA vaccine elicited strong and specific antibody response in vaccination-naive mice. Mice that received two-dose WT LNP-mRNA, the one mimicking the commonly used Pfizer/Moderna mRNA vaccine, showed a >40-fold reduction in neutralization potency against Omicron variant than that against WT two weeks post second dose, which further reduced to background level >3 months post second dose. As a booster shot for two-dose WT mRNA vaccinated mice, a single dose of either a homologous booster with WT LNP-mRNA or a heterologous booster with Omicron LNP-mRNA restored the waning antibody response against Omicron, with over 40-fold increase at two weeks post injection as compared to right before booster. Interestingly, the heterologous Omicron LNP-mRNA booster elicited neutralizing titers 10-20 fold higher than the homologous WT booster against the Omicron variant, with comparable titers against the Delta variant. All three types of vaccination, including Omicron mRNA alone, WT mRNA homologous booster, and Omicron heterologous booster, elicited broad binding antibody responses against SARS-CoV-2 WA-1, Beta, and Delta variants, as well as other Betacoronavirus species such as SARS-CoV, but not Middle East respiratory syndrome coronavirus (MERS-CoV). These data provided direct proof-of-concept assessments of an Omicron-specific mRNA vaccination in vivo, both alone and as a heterologous booster to the existing widely-used WT mRNA vaccine form.

Robust Th1 and Th17 immunity supports pulmonary clearance but cannot prevent systemic dissemination of highly virulent Cryptococcus neoformans H99.

The present study dissected the role of a Th2 bias in pathogenesis of Cryptococcus neoformans H99 infection by comparing inhalational H99 infections in wild-type BALB/c and IL-4/IL-13 double knockout mice. H99-infected wild-type mice showed all major hallmarks of Th2 but not Th1/Th17 immunity in the lungs and lung-associated lymph nodes. In contrast, the IL-4/13(-/-) mice developed robust hallmarks of Th1 and Th17 but not Th2 polarization. The IL-4/IL-13 deletion prevented pulmonary eosinophilia, goblet cell metaplasia in the airways and resulted in elevated serum IgE, and a switch from alternative to classical activation of macrophages. The development of a robust Th1/Th17 response and classical activation of macrophages resulted in significant containment of H99 in the lungs of IL-4/13(-/-) mice compared with unopposed growth of H99 in the lungs of wild-type mice. However, IL-4/13(-/-) mice showed only 1-week longer survival compared with wild-type mice. The comparison of brain and spleen cryptococcal loads at weeks 2, 3, and 4 postinfection revealed that the systemic dissemination in IL-4/13(-/-) mice occurred with an approximate 1-week delay but subsequently progressed with similar rate as in the wild-type mice. Furthermore, wild-type and IL-4/13(-/-) mice developed equivalently severe meningitis/encephalitis at the time of death. These data indicate that the Th2 immune bias is a crucial mechanism for pulmonary virulence of H99, whereas other mechanisms are largely responsible for its central nervous system tropism and systemic dissemination.

Apoptosis is differentially regulated by burn severity and dermal location.

BACKGROUND: The cellular processes that contribute to cell death in burns are poorly understood. This study evaluated the distribution and extent of apoptosis in an established rat model of acute dermal burn injury. MATERIALS AND METHODS: A branding iron (100 degrees C) was applied to the depilated dorsum of seven rats, creating burn contact times of 1-8, 10, 12, and 14 s. Biopsies were collected and immunohistochemistry performed for apoptosis and cell injury/necrosis by detection of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and high-mobility group box 1 (HMGB1), respectively. The slides were scored by evaluating staining in superficial, middle, and deep dermal fields. Within these, basal keratinocytes of the epidermis, mesenchymal cells, adnexal epithelia, and vasculature wall cells were morphometrically analyzed for stain detection of selected markers. RESULTS: TUNEL staining had an inverse relationship with contact time in most fields except in deep dermal mesenchymal cells where it was increased. HMGB1 nuclear staining was significantly decreased with progressive contact time consistent with transition to cell injury/necrosis. CONCLUSIONS: This study is the first to demonstrate that apoptosis rate is dependent on dermal location, cell type, and severity of thermal injury. Furthermore, this work suggests that for most dermal locations increased thermal injury corresponds with decreased apoptosis and increased cell injury/necrosis. Together, these findings indicate that many parameters can regulate apoptosis in burn wounds, and these results will be critical to understanding burn pathogenesis and assessing future therapies.

Pharmacologic modification to resuscitation fluid after thermal injury--is drotrecogin alfa the answer to arrest burn depth progression?

HYPOTHESIS: The addition of drotrecogin alfa (DA), an anti-inflammatory useful in septic shock, to standard burn shock resuscitation fluids will protect burned, injured skin from further injury. METHODS: Anesthetized animals were subjected to a standardized burn pattern by applying a branding iron to 10 different locations on the back of the rat for 1 seconds to 14 seconds, creating a range of burn depths and severities. DESIGN: Animal burn shock and resuscitation model. PARTICIPANTS: Thirty-one male adult Sprague-Dawley rats. INTERVENTIONS: Control animals were resuscitated with lactated Ringer's solution (LRS) at 2 mL/kg/percent total body surface area/24 h; experimental animals received LRS plus DA 24 microg/kg/h (LRS + DA). OUTCOME MEASURES: Perfusion to each burned area was assessed using a laser Doppler imaging technology. Punch biopsies at each burned area were stained with hematoxylin and eosin and assessed for burn depth and for inflammation using previously reported measures. Samples from 14 animals were stained for terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and caspase-3 (apoptosis markers). RESULTS: Increasing branding iron contact times worsened perfusion, burn depth, and apoptotic ratios. There was no correlation between inflammatory markers and burn contact time. The addition of DA leads to worse perfusion, deeper burns, worse inflammation, and decreased apoptotic ratios. CONCLUSIONS: Laser Doppler imaging is a useful technology to assess burn depth. The addition of DA to traditional resuscitation fluids for burn shock is deleterious to the injured, burned skin. Modifying the traditional burn shock resuscitation fluids, although intellectually attractive, needs to be rigorously studied.

Characterisation of site-biased DNA methyltransferases: specificity, affinity and subsite relationships.

DNA methylation is now seen as a primary signal in the cell for mediating transcriptional repression through chromatin formation. The construction and evaluation of enzymes capable of influencing this process in vivo is therefore of significant interest. We have fused the C5-cytosine DNA methyltransferases, M.HhaI and M.HpaII, which both methylate 4 bp sequences containing a CpG dinucleotide, to a three zinc finger protein recognising a 9 bp DNA sequence. DNA methylation analyses demonstrate specific DNA methylation by both enzymes at target sites comprising adjacent methyltransferase and zinc finger subsites, targeted M.HpaII being the most specific. Binding analysis of the targeted M.HpaII enzyme reveals an 8-fold preference for binding to its target site, compared to binding to a zinc finger site alone, and an 18-fold preference over binding to a methyltransferase site alone, thereby demonstrating enhanced binding by the fusion protein, compared to its component proteins. Both DNA binding and methylation are specific for the target site up to separations of approximately 40 bp between the zinc finger and methyltransferase subsites. Ex vivo plasmid methylation experiments are also described that demonstrate targeted methylation. These targeted enzymes, however, are shown to be not fully mono-functional, retaining a significant non-targeted activity most evident at elevated protein concentrations.

Hand Blisters in Major League Baseball Pitchers: Current Concepts and Management.

Friction blisters are a common sequela of many athletic activities. Their significance can range from minor annoyance to major performance disruptions. The latter is particularly true in baseball pitchers, who sustain repeated trauma between the baseball seams and the fingers of the pitching hand, predominately at the tips of the index and long fingers. Since 2010, 6 Major League Baseball (MLB) players accounted for 7 stints on the disabled list (DL) due to blisters. These injuries resulted in a total of 151 days spent on the DL. Since 2012, 8 minor league players spent time on the DL due to blisters. Moreover, there have been several documented and publicized instances of professional baseball pitchers suffering blisters that did not require placement on the DL but did result in injury time and missed starts. The purpose of this article is to review the etiology and pathophysiology of friction blisters with particular reference to baseball pitchers; provide an overview of past and current prevention methods; and discuss our experience in treating friction blisters in MLB pitchers.

2013 Winning Essay: The Accountable Care Paradigm Shift: New Ethical Considerations.

The current state of our health care system is analogous to the status of science that Kuhn describes as "a proliferation of compelling articulations, the willingness to try anything, the expression of explicit discontent, the recourse to philosophy and to debate over fundamentals" [27]. ACOs represent a paradigm shift in the way health care is delivered. As with any dramatic public policy change, ethical issues will arise. These are surmountable challenges, and with open communication, physicians such as the Midstate group can partner effectively with hospital systems to ensure the delivery of quality, evidence-based care while at the same reorienting the culture to be attentive to its fiduciary responsibilities.

Nonoperative Treatment of Posterior Wall Acetabular Fractures After Dynamic Stress Examination Under Anesthesia: Revisited.

OBJECTIVES: Performing an examination under general anesthesia (EUA) using dynamic stress fluoroscopy of patients with posterior wall acetabular fractures has been used as a tool to determine hip stability and the need for surgical intervention. The purpose of this study was to further evaluate the effectiveness of this technique, from a source other than its primary advocates, in patients with posterior wall acetabular fractures less than or equal to 50% who were stable on EUA and treated nonoperatively. DESIGN: Retrospective case series. SETTING: University Level 1 Trauma Center. PARTICIPANTS: Seventeen patients with a posterior wall acetabular fracture stable on EUA treated nonoperatively. INTERVENTION: The patients were treated nonoperatively as guided by an EUA negative for instability. Patient follow-up averaged 30 months (range, 6-64 months). MAIN OUTCOME MEASUREMENTS: Outcome evaluation included the modified Merle d'Aubigné clinical score and the Short Musculoskeletal Function Assessment Questionnaire. Radiographic evaluation for subluxation or arthritis consisted of the 3 standard pelvic radiographs. RESULTS: Radiographic evaluation showed all hips to be congruent with a normal joint space. Sixteen of the 17 patients had radiographic outcomes rated as "excellent"; 1 patient was rated "good." The modified Merle d'Aubigné score (obtained in 12 patients) averaged very good, with only 1 having less than a good (graded as fair) clinical outcome. The Short Musculoskeletal Function Assessment Questionnaire scores (from 11 patients) were not significantly different from normal and were within the normal reported values for all indices and categories. There was no correlation between fracture fragment size and outcome. CONCLUSIONS: This study further supports the contention that a stable hip joint, as determined by EUA, after posterior wall acetabular fracture treated nonoperatively is predictive of continued joint congruity, an excellent radiographic outcome, and good-to-excellent early clinical and functional outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Acquisition of operant behavior in rats with delayed reinforcement: A retractable-lever procedure.

Experimentally naïve rats acquired lever pressing with delayed reinforcement when the immediate programmed consequence for lever pressing was the simultaneous retraction of two identical levers. Presses on one lever also produced access to sweetened condensed milk after a delay of 10s following retraction. Presses on the second lever resulted in retraction only. Lever retraction prevented the possibility of adventitious reinforcement of contacting the operanda during the reinforcement delays. Several measures indicated that the delayed reinforcers strengthened behavior. The majority of responses for all rats were on the lever that initiated reinforcer delivery. Responding for seven out of eight rats decreased during a subsequent extinction phase in which retraction was the only consequence arranged for lever pressing. Responding recovered rapidly when food reinforcement was available again. Furthermore, when contingencies on the two levers were switched, rats allocated their behavior accordingly, showing control by the delayed reinforcers.