Accident proneness, laterality, and time estimation.

Cerebral laterality has been linked to accident proneness and time perception, but the possible role of time estimation abilities has received little attention. Accordingly, the present study focused on this under-explored question while also aiming to replicate past work examining the relationship between measures of laterality and injury proneness. Participants reported on the number of accidents they have had in their lifetime requiring medical care and the number of minor accidents they had in the past month as outcome variables. They also completed the Waterloo Handedness Questionnaire, a left bias visual task (Greyscales task), a right bias auditory verbal task (Fused Dichotic Words Task), and an objective measure of time perception. Extensive examination of statistical model fit showed that a model assuming a Poisson distribution provided the best fit for minor injuries and an additional negative binomial provided the best fit to the lifetime accidents. Results showed a negative relation between the degree of verbal laterality (absolute right bias) and injuries requiring medical care. Furthermore, the number of accidents requiring medical care was positively related to the precision of time estimation and the direction of verbal laterality on response time (raw right bias). Interpretations of these findings emphasize their implications for interhemispheric communication and motor control in the context of time estimation and auditory verbal laterality. These aspects seem to provide promising avenues for future research.

Tyrosine Nitration Contributes to Nitric Oxide-Stimulated Degradation of CYP2B6.

Human cytochrome P450 (P450) CYP2B6 undergoes nitric oxide (NO)-dependent proteasomal degradation in response to the NO donor dipropylenetriamine NONOate (DPTA) and biologic NO in HeLa and HuH7 cell lines. CYP2B6 is also downregulated by NO in primary human hepatocytes. We hypothesized that NO or derivative reactive nitrogen species may generate adducts of tyrosine and/or cysteine residues, causing CYP2B6 downregulation, and selected Tyr and Cys residues for mutation based on predicted solvent accessibility. CYP2B6V5-Y317A, -Y380A, and -Y190A mutant proteins expressed in HuH7 cells were less sensitive than wild-type (WT) enzyme to degradation evoked by DPTA, suggesting that these tyrosines are targets for NO-dependent downregulation. The Y317A or Y380A mutants did not show increases in high molecular mass (HMM) species after treatment with DPTA or bortezomib + DPTA, in contrast to the WT enzyme. Carbon monoxide-releasing molecule 2 treatment caused rapid suppression of 2B6 enzyme activity, significant HMM species generation, and ubiquitination of CYP2B6 protein but did not stimulate CYP2B6 degradation. The CYP2B6 inhibitor 4-(4-chlorophenyl)imidazole blocked NO-dependent CYP2B6 degradation, suggesting that NO access to the active site is important. Molecular dynamics simulations predicted that tyrosine nitrations of CYP2B6 would cause significant destabilizing perturbations of secondary structure and remove correlated motions likely required for enzyme function. We propose that cumulative nitrations of Y190, Y317, and Y380 by reactive nitrogen species cause destabilization of CYP2B6, which may act synergistically with heme nitrosylation to target the enzyme for degradation. SIGNIFICANCE STATEMENT: This work provides novel insight into the mechanisms by which nitric oxide, which is produced in hepatocytes in response to inflammation, triggers the ubiquitin-dependent proteasomal degradation of the cytochrome P450 (P450) enzyme CYP2B6. Our data demonstrate that both nitration of specific tyrosine residues and interaction of nitric oxide (NO) with the P450 heme are necessary for NO to trigger ubiquitination and protein degradation.

Murine gammaherpesvirus infection is skewed toward Igλ+ B cells expressing a specific heavy chain V-segment.

One of the defining characteristics of the B cell receptor (BCR) is the extensive diversity in the repertoire of immunoglobulin genes that make up the BCR, resulting in broad range of specificity. Gammaherpesviruses are B lymphotropic viruses that establish life-long infection in B cells, and although the B cell receptor plays a central role in B cell biology, very little is known about the immunoglobulin repertoire of gammaherpesvirus infected cells. To begin to characterize the Ig genes expressed by murine gammaherpesvirus 68 (MHV68) infected cells, we utilized single cell sorting to sequence and clone the Ig variable regions of infected germinal center (GC) B cells and plasma cells. We show that MHV68 infection is biased towards cells that express the Igλ light chain along with a single heavy chain variable gene, IGHV10-1*01. This population arises through clonal expansion but is not viral antigen specific. Furthermore, we show that class-switching in MHV68 infected cells differs from that of uninfected cells. Fewer infected GC B cells are class-switched compared to uninfected GC B cells, while more infected plasma cells are class-switched compared to uninfected plasma cells. Additionally, although they are germinal center derived, the majority of class switched plasma cells display no somatic hypermutation regardless of infection status. Taken together, these data indicate that selection of infected B cells with a specific BCR, as well as virus mediated manipulation of class switching and somatic hypermutation, are critical aspects in establishing life-long gammaherpesvirus infection.

A non-lethal malarial infection results in reduced drug metabolizing enzyme expression and drug clearance in mice.

BACKGROUND: Given the central importance of anti-malarial drugs in the treatment of malaria, there is a need to understand the effect of Plasmodium infection on the broad spectrum of drug metabolizing enzymes. Previous studies have shown reduced clearance of quinine, a treatment for Plasmodium infection, in individuals with malaria. METHODS: The hepatic expression of a large panel of drug metabolizing enzymes was studied in the livers of mice infected with the AS strain of Plasmodium chabaudi chabaudi, a nonlethal parasite in most strains of mice with several features that model human Plasmodium infections. C57BL/6J mice were infected with P. chabaudi by intraperitoneal injection of infected erythrocytes and sacrificed at different times after infection. Relative hepatic mRNA levels of various drug metabolizing enzymes, cytokines and acute phase proteins were measured by reverse transcriptase-real time PCR. Relative levels of cytochrome P450 proteins were measured by Western blotting with IR-dye labelled antibodies. Pharmacokinetics of 5 prototypic cytochrome P450 substrate drugs were measured by cassette dosing and high-resolution liquid chromatography-mass spectrometry. The results were analysed by MANOVA and post hoc univariate analysis of variance. RESULTS: The great majority of enzyme mRNAs were down-regulated, with the greatest effects occurring at the peak of parasitaemia 8 days post infection. Protein levels of cytochrome P450 enzymes in the Cyp 2b, 2c, 2d, 2e, 3a and 4a subfamilies were also down-regulated. Several distinct groups differing in their temporal patterns of regulation were identified. The cassette dosing study revealed that at the peak of parasitaemia, the clearances of caffeine, bupropion, tolbutamide and midazolam were markedly reduced by 60-70%. CONCLUSIONS: These findings in a model of uncomplicated human malaria suggest that changes in drug clearance in this condition may be of sufficient magnitude to cause significant alterations in exposure and response of anti-malarial drugs and co-medications.

Minimally invasive surgical management of spontaneous esophageal perforation (Boerhaave's syndrome).

BACKGROUND: Spontaneous esophageal perforation (Boerhaave's syndrome) is a highly morbid condition traditionally associated with poor outcomes. The Pittsburgh perforation severity score (PSS) accurately predicts risk of morbidity, length of stay (LOS) and mortality. Operative management is indicated among patients with medium (3-5) or high (> 5) PSS; however, the role of minimally invasive surgery remains uncertain. METHODS: Consecutive patients presenting with Boerhaave's syndrome with intermediate or high PSS managed via a thoracoscopic and laparoscopic approach from 2012 to 2018 were reviewed. Demographics, clinical presentation, management, and outcomes were analyzed. RESULTS: Ten patients (80% male) with a mean age of 61.3 years (range 37-81) were included. Two patients had intermediate and eight had high PSS (7.9 ± 2.8, range 4-12). The mean time from onset of symptoms to diagnosis was 27 ± 12 h and APACHE II score was 13.6 ± 4.9. Thoracoscopic debridement and primary repair was performed in eight cases, with two perforations repaired primarily over a T-tube. Laparoscopic feeding jejunostomy was performed in all patients. Critical care LOS was 8.7 ± 6.8 days (range 3-26), while inpatient LOS was 23.1 ± 12.5 days (range 14-46). Mean comprehensive complications index was 42.1 ± 26.2, with grade IIIa and IV morbidity in 60% and 10%, respectively. One patient developed dehiscence at the primary repair, which was managed non-operatively. In-hospital and 90-day mortality was 10%. CONCLUSION: Minimally invasive surgical management of spontaneous esophageal perforation with medium to high perforation severity scores is feasible and safe, with outcomes which compare favorably to the published literature.

Progesterone receptor in the vascular endothelium triggers physiological uterine permeability preimplantation.

Vascular permeability is frequently associated with inflammation and is triggered by a cohort of secreted permeability factors such as vascular endothelial growth factor (VEGF). Here, we show that the physiological vascular permeability that precedes implantation is directly controlled by progesterone receptor (PR) and is independent of VEGF. Global or endothelial-specific deletion of PR blocks physiological vascular permeability in the uterus, whereas misexpression of PR in the endothelium of other organs results in ectopic vascular leakage. Integration of an endothelial genome-wide transcriptional profile with chromatin immunoprecipitation sequencing revealed that PR induces an NR4A1 (Nur77/TR3)-dependent transcriptional program that broadly regulates vascular permeability in response to progesterone. Silencing of NR4A1 blocks PR-mediated permeability responses, indicating a direct link between PR and NR4A1. This program triggers concurrent suppression of several junctional proteins and leads to an effective, timely, and venous-specific regulation of vascular barrier function that is critical for embryo implantation.

Death by late-presenting Bochdalek hernia in infant soon after congenital cardiac repair.

Congenital diaphragmatic hernia (CDH) presenting beyond the neonatal period is commonly perceived to be rare. With reported frequencies of 2.6% to 20% of all CDH, it may be an overlooked cause of mortality. Variable symptomatology makes its diagnosis challenging. We report the sudden death of a 3-month-old patient shortly after hospital discharge following congenital heart surgery. Autopsy findings associated the patient's demise with migrated abdominal contents in the chest through a Bochdalek hernia defect. No indications of CDH existed before hospital discharge. Relevant issues pertaining to congenital heart disease, CDH, and importance of autopsy in this context are discussed.

Multimodality therapy for adenocarcinoma of the esophagus, gastric cardia, and upper gastric third.

There is considerable controversy over the level of recommendations from randomized trials underpinning management decisions for patients presenting with localized adenocarcinoma of the esophagus and esophagogastric junction. Despite a paucity of Level 1 recommendations compared with other gastrointestinal sites, in particular rectal cancer, there is an emerging consensus in practice to consider multimodal approaches in all cases that present with T3 or node-positive disease. There is also an optimism that new approaches, including response prediction based on sequential 18FDG-PET scanning following induction chemotherapy, and novel drugs targeted at EGF, EGFR, VEGF, and tyrosine kinase inhibition may improve treatment pathways and outcomes. In this review, we assess the level of recommendations from the major published trials and -discuss new trials and approaches.

Treatment options for esophageal cancer.

There is considerable controversy over the level of evidence from randomized trials underpinning management decisions for patients presenting with localized cancer of the esophagus and esophago-gastric junction. There is also an optimism that new drugs and new approaches, including response prediction based on sequential (18)FDG-PET scanning following induction chemotherapy, may improve treatments pathways and outcomes. In this review we assess the level of evidence from the major published trials, and discuss new trials and approaches.

A role for IkappaB kinase 2 in bipolar spindle assembly.

IkappaB kinase 2 (IKK2 or IKKbeta) is a component of the IKK complex that coordinates the cellular response to a diverse set of extracellular stimuli, including cytokines, microbial infection, and stress. In response to an external stimulus, the complex is activated, resulting in the phosphorylation and subsequent proteasome-mediated degradation of IkappaB proteins. This event triggers the nuclear import of the NF-kappaB transcription factor, which activates the transcription of genes that regulate a variety of fundamental biological processes, including immune response, cell survival, and development. Here, we define an essential role for IKK2 in normal mitotic progression and the maintenance of spindle bipolarity. Chemical and genetic perturbation of IKK2 promotes the formation of multipolar spindles and chromosome missegregation. Depletion of IKK2 results in the deregulation of Aurora A protein stability and coincident hyperactivation of a putative Aurora A substrate, the mitotic motor KIF11. These data support a function for IKK2 as an antagonist of Aurora A signaling during mitosis. Additionally, our results indicate a direct role for IKK2 in the maintenance of genome stability and underscore the potential for oncogenic consequences in targeting this kinase for therapeutic intervention.

Platelet-derived growth factor-induced stabilization of cyclooxygenase 2 mRNA in rat smooth muscle cells requires the c-Src family of protein-tyrosine kinases.

Cyclooxygenases (COXs) are crucial rate-limiting enzymes required for the biosynthesis of prostaglandins. COX-2 is an inducible isoform of this enzyme, which is believed to play important roles in the development of atherosclerotic vascular disease. We found that COX-2 expression rapidly increases in response to various signaling events, including activation of the platelet-derived growth factor (PDGF) pathway. Activation of PDGF receptor (PDGFR) in rat aortic vascular smooth muscle cells leads to c-Src-dependent stabilization of COX-2 mRNA requiring an AU-rich region within the 3'-untranslated region of this transcript. This regulation correlates with tyrosine phosphorylation of the RNA-associated protein, CUG-binding protein 2 (CUGBP2), which appears to enhance its interaction with COX-2 mRNA. Site-directed mutagenesis of putative tyrosine phosphorylation sites in CUGBP2 identified tyrosine 39 as a c-Src target, and a CUGBP2 with a mutated tyrosine 39 displayed an attenuated ability to bind COX-2 mRNA. We further show that silencing of CUGBP2 with specific small interference RNAs significantly reduces PDGF-dependent induction of COX-2 at both mRNA and protein levels. Furthermore, forced expression of CUGBP2 or constitutively active c-Src leads to stabilization of co-expressed COX-2 mRNA. Finally, in vitro RNA decay assay demonstrates that CUGBP2 is functionally required for the stabilization of COX-2 mRNA. Therefore, our data suggest that tyrosine phosphorylation of CUGBP2 is an important underlying mechanism for the ability of PDGFR/c-Src signaling to control the stability of COX-2 mRNA.

Long-term outcomes following neoadjuvant chemoradiotherapy for esophageal cancer.

OBJECTIVE: We present and analyze long-term outcomes following multimodal therapy for esophageal cancer, in particular the relative impact of histomorphologic tumor regression and nodal status. PATIENTS AND METHODS: A total of 243 patients [(adenocarcinoma (n = 170) and squamous cell carcinoma (n = 73)] treated with neoadjuvant chemoradiotherapy in the period 1990 to 2004 were followed prospectively with a median follow-up of 60 months. Pathologic stage and tumor regression grade (TRG) were documented, the site of first failure was recorded, and Kaplan-Meier survival curves were plotted. RESULTS: Thirty patients (12%) did not undergo surgery due to disease progression or deteriorated performance status. Forty-one patients (19%) had a complete pathologic response (pCR), and there were 31(15%) stage I, 69 (32%) stage II, and 72 (34%) stage III cases. The overall median survival was 18 months, and the 5-year survival was 27%. The 5-year survival of patients achieving a pCR was 50% compared with 37% in non-pCR patients who were node-negative (P = 0.86). Histomorphologic tumor regression was not associated with pre-CRT cTN stage but was significantly (P < 0.05) associated with ypN stage. By multivariate analysis, ypN status (P = 0.002) was more predictive of overall survival than TRG (P = 0.06) or ypT stage (P = 0.39). CONCLUSION: Achieving a node-negative status is the major determinant of outcome following neoadjuvant chemoradiotherapy. Histomorphologic tumor regression is less predictive of outcome than pathologic nodal status (ypN), and the need to include a primary site regression score in a new staging classification is unclear.

Enhanced regulatory T cell activity is an element of the host response to injury.

CD4+CD25+ regulatory T cells (Tregs) play a critical role in suppressing the development of autoimmune disease, in controlling potentially harmful inflammatory responses, and in maintaining immune homeostasis. Because severe injury triggers both excessive inflammation and suppressed adaptive immunity, we wished to test whether injury could influence Treg activity. Using a mouse burn injury model, we demonstrate that injury significantly enhances Treg function. This increase in Treg activity is apparent at 7 days after injury and is restricted to lymph node CD4+CD25+ T cells draining the injury site. Moreover, we show that this injury-induced increase in Treg activity is cell-contact dependent and is mediated in part by increased cell surface TGF-beta1 expression. To test the in vivo significance of these findings, mice were depleted of CD4+CD25+ T cells before sham or burn injury and then were immunized to follow the development of T cell-dependent Ag-specific immune reactivity. We observed that injured mice, which normally demonstrate suppressed Th1-type immunity, showed normal Th1 responses when depleted of CD4+CD25+ T cells. Taken together, these observations suggest that injury can induce or amplify CD4+CD25+ Treg function and that CD4+CD25+ T cells contribute to the development of postinjury immune suppression.

CD4+CD25+ regulatory T cells control innate immune reactivity after injury.

Major injury initiates a systemic inflammatory response that can be detrimental to the host. We have recently reported that burn injury primes innate immune cells for a progressive increase in TLR4 and TLR2 agonist-induced proinflammatory cytokine production and that this inflammatory phenotype is exaggerated in adaptive immune system-deficient (Rag1(-/-)) mice. The present study uses a series of adoptive transfer experiments to determine which adaptive immune cell type(s) has the capacity to control innate inflammatory responses after injury. We first compared the relative changes in TLR4- and TLR2-induced TNF-alpha, IL-1beta, and IL-6 production by spleen cell populations prepared from wild-type (WT), Rag1(-/-), CD4(-/-), or CD8(-/-) mice 7 days after sham or burn injury. Our findings indicated that splenocytes prepared from burn-injured CD8(-/-) mice displayed TLR-induced cytokine production levels similar to those in WT mice. In contrast, spleen cells from burn-injured CD4(-/-) mice produced cytokines at significantly higher levels, equivalent to those in Rag1(-/-) mice. Moreover, reconstitution of Rag1(-/-) or CD4(-/-) mice with WT CD4(+) T cells reduced postinjury cytokine production to WT levels. Additional separation of CD4(+) T cells into CD4(+)CD25(+) and CD4(+)CD25(-) subpopulations before their adoptive transfer into Rag1(-/-) mice showed that CD4(+)CD25(+) T cells were capable of reducing TLR-stimulated cytokine production levels to WT levels, whereas CD4(+)CD25(-) T cells had no regulatory effect. These findings suggest a previously unsuspected role for CD4(+)CD25(+) T regulatory cells in controlling host inflammatory responses after injury.

Linking the "two-hit" response following injury to enhanced TLR4 reactivity.

Severe injury can initiate an exaggerated systemic inflammatory response and multiple organ failure (MOF) if a subsequent immune stimulus, "second hit", occurs. Using a mouse thermal injury model, we tested whether changes in innate immune cell reactivity following injury can contribute to the development of heightened inflammation and MOF. Using high-purity Escherichia coli lipopolysaccharide (LPS) to selectively stimulate Toll-like receptor 4 (TLR4), we demonstrate augmented interleukin (IL)-1beta, tumor necrosis factor alpha (TNF-alpha), and IL-6 production by 1 day but particularly, at 7 days after injury. The in vivo significance of enhanced TLR4 responsiveness was explored by challenging sham or burn mice with LPS at 1 or 7 days after injury and determining mortality along with in vivo cytokine and chemokine levels. Mortality was high (75%) in LPS-challenged burn but not sham mice at 7 days, although not at 1 day, after injury. Death was associated with leukocyte sequestration in the lungs and livers along with increased proinflammatory cytokine and chemokine levels in these organs. Blocking TNF-alpha activity prevented this mortality, suggesting that excessive TNF-alpha production contributes to this lethal response. These findings demonstrate the potential lethality of excessive TLR4 reactivity after injury and provide an explanation for the exaggerated inflammatory response to a second hit, which can occur following severe injury.

Burn injury initiates a shift in superantigen-induced T cell responses and host survival.

Severe injury induces a temporal shift in immune reactivity that can cause serious complications or even death. We previously reported that mice exposed to bacterial superantigen (SAg) early after injury undergo a strong SAg response with lethal consequences. This study compares the early and late effects of burn injury on SAg reactivity in vivo to establish how injury influences adaptive immune responses. We found that mice challenged with ordinarily sublethal doses of staphylococcal enterotoxin A or staphylococcal enterotoxin B at 1 day after burn injury exhibited high mortality, whereas no mortality occurred at 7 days after injury. This shift in mortality correlated with higher Th2-type cytokines (IL-4 and IL-10) being expressed by CD4(+) and CD8(+) T cells from burn as opposed to sham mice at 7 days after injury. Lymph node cells from burn-injured mice also produced higher levels of Th2-type cytokines at 7 days after injury. The results of cell-mixing studies using CD4(+) and CD8(+) T cells mixed with APCs from sham or burn mice suggested that changes in both T cells and APCs are involved in the altered SAg response. Finally, the biological significance of altered SAg reactivity following injury was shown by demonstrating that blocking IL-10 activity in vivo caused higher SAg-induced mortality at 7 days after injury. These findings support the idea that injury promotes a Th2-type shift in adaptive immune reactivity. Although prior studies link this counterinflammatory-type response to lowered resistance to infection, the present results suggest it may sometimes benefit the injured host.