Neurosyphilis: A Simulation Case for Emergency Medicine Residents.

Neurosyphilis is a dangerous and increasingly more prevalent sexually transmitted infection of the central nervous system caused by the bacterium Treponemapallidum that can present during the advanced stages of the disease (tertiary syphilis). Health care providers must remain vigilant in screening for syphilis in patients with high-risk behaviors as a delay in diagnosis and treatment may lead to symptom progression and debilitating sequelae years later. To date, there have been no published simulation case studies on neurosyphilis. This simulation case, based on a real patient encounter, is written for emergency medicine residents to diagnose and manage a patient presenting with the sequelae of neurosyphilis. This case was run for four separate iterations at a simulation center with two residents and an attending physician acting as confederates. Following the case, learners were provided with bedside debriefing, and a question and answer session. Based on post-simulation qualitative assessment, junior residents alone were less likely to perform a comprehensive integumentary exam without the presence of senior residents, although both groups failed to elicit pertinent sexual history until they discovered syphilitic lesions. After case completion and debriefing, all learners were able to demonstrate the understanding of the primary learning objectives.

Man with a Swollen Eye: Nonspecific Orbital Inflammation in an Adult in the Emergency Department.

BACKGROUND: Nonspecific orbital inflammation (NSOI) is a rare idiopathic ocular pathology characterized by unilateral, painful orbital swelling without identifiable infectious or systemic disorders, which can be complicated by optic nerve compromise. CASE REPORT: A 50-year-old man presented to the Emergency Department with recurring, progressive painless left eye swelling, decreased visual acuity, and binocular diplopia in the absence of trauma, infection, or known malignancy. His physical examination was notable for left-sided decreased visual acuity, an afferent pupillary defect, severe left eye proptosis and chemosis, and restricted extraocular movements; his dilatated funduscopic examination was notable for ipsilateral retinal folds within the macula, concerning for a disruption between the sclera and the retina. Ocular examination of the right eye was unremarkable. Laboratory data were unrevealing. Gadolinium-enhanced magnetic resonance imaging showed marked thickening of the left extraocular muscles associated with proptosis, dense inflammatory infiltration of the orbital fat, and characteristics consistent with perineuritis. The patient was diagnosed with NSOI with optic neuritis and admitted for systemic steroid therapy; he was discharged on hospital day 2 after receiving high-dose intravenous (i.v.) methylprednisolone with significant improvement. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: NSOI is a rare and idiopathic ocular emergency, with clinical mimicry resembling a broad spectrum of systemic diseases such as malignancy, autoimmune diseases, endocrine disorders, and infection. Initial work-up for new-onset ocular proptosis should include comprehensive laboratory testing and gadolinium-enhanced magnetic resonance imaging. Timely evaluation by an ophthalmologist is crucial to assess for optic nerve involvement. Signs of optic nerve compromise include decreased visual acuity, afferent pupillary defect, or decreased color saturation. Patients with optic nerve compromise require admission for aggressive anti-inflammatory therapy with i.v. steroids in an attempt to reduce risk of long-term visual sequelae. Our case demonstrates a severe presentation of this disorder and exhibits remarkable visual recovery after 48 h of systemic i.v. steroid treatment.

The Composition of Human Milk and Infant Faecal Microbiota Over the First Three Months of Life: A Pilot Study.

Human milk contains a diverse array of bioactives and is also a source of bacteria for the developing infant gut. The aim of this study was to characterize the bacterial communities in human milk and infant faeces over the first 3 months of life, in 10 mother-infant pairs. The presence of viable Bifidobacterium and Lactobacillus in human milk was also evaluated. MiSeq sequencing revealed a large diversity of the human milk microbiota, identifying over 207 bacterial genera in milk samples. The phyla Proteobacteria and Firmicutes and the genera Pseudomonas, Staphylococcus and Streptococcus were the predominant bacterial groups. A core of 12 genera represented 81% of the microbiota relative abundance in milk samples at week 1, 3 and 6, decreasing to 73% at week 12. Genera shared between infant faeces and human milk samples accounted for 70-88% of the total relative abundance in infant faecal samples, supporting the hypothesis of vertical transfer of bacteria from milk to the infant gut. In addition, identical strains of Bifidobacterium breve and Lactobacillus plantarum were isolated from the milk and faeces of one mother-infant pair. Vertical transfer of bacteria via breastfeeding may contribute to the initial establishment of the microbiota in the developing infant intestine.

Communication of Vital Signs at Emergency Department Handoff: Opportunities for Improvement.

STUDY OBJECTIVE: We describe the prevalence of vital sign communication errors during emergency department (ED) handoffs. Our secondary objective is to evaluate the association between handoff behaviors and ED crowding on vital sign handoff errors. METHODS: This was a prospective observational study of ED handoffs conducted at an urban academic hospital. We observed a prespecified convenience sample of ED shift rounds and included all patients whose care was subject to a handoff during ED shift change. The primary outcome was vital sign communication errors, defined as the failure to communicate an episode of medical-record-documented hypotension or hypoxia during ED shift rounds. Trained research assistants used a standardized data collection tool to collect data through direct observation and electronic health record abstraction. We report descriptive statistics and results of a logistic regression model constructed with generalized estimating equations to describe the association between handoff and rounds-level characteristics and handoff errors. RESULTS: We observed 1,163 patient handoffs during 130 ED shift rounds. Of 117 patients with episodes of hypotension and 156 patients with hypoxia, 66 (42%) and 116 (74%) were not communicated at rounds, respectively. One hundred sixty-six handoffs (14%) included a vital sign communication error of omission. In multivariate analysis, no handoff or rounds characteristic, including the ED occupancy rate, was associated with omission errors of vital sign communication. CONCLUSION: Providers omitted communication of patient hypotension or hypoxia in nearly 1 in 7 ED handoffs. These communication errors do not appear to be related to ED crowding or care interruptions.

mTORC1 activation blocks BrafV600E-induced growth arrest but is insufficient for melanoma formation.

Braf(V600E) induces benign, growth-arrested melanocytic nevus development, but also drives melanoma formation. Cdkn2a loss in Braf(V600E) melanocytes in mice results in rare progression to melanoma, but only after stable growth arrest as nevi. Immediate progression to melanoma is prevented by upregulation of miR-99/100, which downregulates mTOR and IGF1R signaling. mTORC1 activation through Stk11 (Lkb1) loss abrogates growth arrest of Braf(V600E) melanocytic nevi, but is insufficient for complete progression to melanoma. Cdkn2a loss is associated with mTORC2 and Akt activation in human and murine melanocytic neoplasms. Simultaneous Cdkn2a and Lkb1 inactivation in Braf(V600E) melanocytes results in activation of both mTORC1 and mTORC2/Akt, inducing rapid melanoma formation in mice. In this model, activation of both mTORC1/2 is required for Braf-induced melanomagenesis.

Evaluation of a clinical tool for early etiology identification in status epilepticus.

OBJECTIVES: Because early etiologic identification is critical to select appropriate specific status epilepticus (SE) management, we aim to validate a clinical tool we developed that uses history and readily available investigations to guide prompt etiologic assessment. METHODS: This prospective multicenter study included all adult patients treated for SE of all but anoxic causes from four academic centers. The proposed tool is designed as a checklist covering frequent precipitating factors for SE. The study team completed the checklist at the time the patient was identified by electroencephalography (EEG) request. Only information available in the emergency department or at the time of in-hospital SE identification was used. Concordance between the etiology indicated by the tool and the determined etiology at hospital discharge was analyzed, together with interrater agreement. RESULTS: Two hundred twelve patients were included. Concordance between the etiology hypothesis generated using the tool and the finally determined etiology was 88.7% (95% confidence interval (CI) 86.4-89.8) (κ = 0.88). Interrater agreement was 83.3% (95% CI 80.4-96) (κ = 0.81). SIGNIFICANCE: This tool is valid and reliable for identification early the etiology of an SE. Physicians managing patients in SE may benefit from using it to identify promptly the underlying etiology, thus facilitating selection of the appropriate treatment.

Boarding is associated with higher rates of medication delays and adverse events but fewer laboratory-related delays.

BACKGROUND: Hospital crowding and emergency department (ED) boarding are large and growing problems. To date, there has been a paucity of information regarding the quality of care received by patients boarding in the ED compared with the care received by patients on an inpatient unit. We compared the rate of delays and adverse events at the event level that occur while boarding in the ED vs while on an inpatient unit. METHODS: This study was a secondary analysis of data from medical record review and administrative databases at 2 urban academic teaching hospitals from August 1, 2004, through January 31, 2005. We measured delayed repeat cardiac enzymes, delayed partial thromboplastin time level checks, delayed antibiotic administration, delayed administration of home medications, and adverse events. We compared the incidence of events during ED boarding vs while on an inpatient unit. RESULTS: Among 1431 patient medical records, we identified 1016 events. Emergency department boarding was associated with an increased risk of home medication delays (risk ratio [RR], 1.54; 95% confidence interval [CI], 1.26-1.88), delayed antibiotic administration (RR, 2.49; 95% CI, 1.72-3.52), and adverse events (RR, 2.36; 95% CI, 1.15-4.72). On the contrary, ED boarding was associated with fewer delays in repeat cardiac enzymes (RR, 0.17; 95% CI, 0.09-0.27) and delayed partial thromboplastin time checks (RR, 0.54; 95% CI, 0.27-0.96). CONCLUSION: Compared with inpatient units, ED boarding was associated with more medication-related delays and adverse events but fewer laboratory-related delays. Until we can eliminate ED boarding, it is critical to identify areas for improvement.

ß-catenin signaling controls metastasis in Braf-activated Pten-deficient melanomas.

Malignant melanoma is characterized by frequent metastasis, however, specific changes that regulate this process have not been clearly delineated. Although it is well known that Wnt signaling is frequently dysregulated in melanoma, the functional implications of this observation are unclear. By modulating ß-catenin levels in a mouse model of melanoma that is based on melanocyte-specific Pten loss and Braf(V600E) mutation, we demonstrate that ß-catenin is a central mediator of melanoma metastasis to the lymph nodes and lungs. In addition to altering metastasis, ß-catenin levels control tumor differentiation and regulate both MAPK/Erk and PI3K/Akt signaling. Highly metastatic tumors with ß-catenin stabilization are very similar to a subset of human melanomas. Together these findings establish Wnt signaling as a metastasis regulator in melanoma.

Characterization of melanoma cells capable of propagating tumors from a single cell.

Questions persist about the nature and number of cells with tumor-propagating capability in different types of cancer, including melanoma. In part, this is because identification and characterization of purified tumorigenic subsets of cancer cells has not been achieved to date. Here, we report tumor formation after injection of single purified melanoma cells derived from three novel mouse models. Tumor formation occurred after every injection of individual CD34+p75- melanoma cells, with intermediate rates using CD34-p75- cells, and rarely with CD34-p75+ cells. These findings suggest that tumorigenic melanoma cells may be more common than previously thought and establish that multiple distinct populations of melanoma-propagating cells (MPC) can exist within a single tumor. Interestingly, individual CD34-p75- MPCs could regenerate cellular heterogeneity after tumor formation in mice or multiple passages in vitro, whereas CD34+p75- MPCs underwent self-renewal only, showing that reestablishment of tumor heterogeneity is not always a characteristic of individual cells capable of forming tumors. Functionally, single purified MPCs were more resistant to chemotherapy than non-MPCs. We anticipate that purification of these MPCs may allow a more comprehensive evaluation of the molecular features that define tumor-forming capability and chemotherapeutic resistance in melanoma.

Braf(V600E) cooperates with Pten loss to induce metastatic melanoma.

Mutational activation of BRAF is the earliest and most common genetic alteration in human melanoma. To build a model of human melanoma, we generated mice with conditional melanocyte-specific expression of BRaf(V600E). Upon induction of BRaf(V600E) expression, mice developed benign melanocytic hyperplasias that failed to progress to melanoma over 15-20 months. By contrast, expression of BRaf(V600E) combined with Pten tumor suppressor gene silencing elicited development of melanoma with 100% penetrance, short latency and with metastases observed in lymph nodes and lungs. Melanoma was prevented by inhibitors of mTorc1 (rapamycin) or MEK1/2 (PD325901) but, upon cessation of drug administration, mice developed melanoma, indicating the presence of long-lived melanoma-initiating cells in this system. Notably, combined treatment with rapamycin and PD325901 led to shrinkage of established melanomas. These mice, engineered with a common genetic profile to human melanoma, provide a system to study melanoma's cardinal feature of metastasis and for preclinical evaluation of agents designed to prevent or treat metastatic disease.

Loss of xeroderma pigmentosum C (Xpc) enhances melanoma photocarcinogenesis in Ink4a-Arf-deficient mice.

Despite an extensive body of evidence linking UV radiation and melanoma tumorigenesis, a clear mechanistic understanding of this process is still lacking. Because heritable mutations in both INK4a and the nucleotide excision repair (NER) pathway predispose individuals to melanoma development, we set out to test the hypothesis that abrogation of NER, by deletion of the xeroderma pigmentosum C (Xpc) gene, will heighten melanoma photocarcinogenesis in an Ink4a-Arf-deficient background. Experimentally, we generated a strain of mice doubly deficient in Xpc and Ink4a-Arf and subjected wild-type, Xpc-/-Ink4a-Arf+/+, Xpc-/-Ink4a-Arf-/-, and Xpc+/+Ink4a-Arf-/- mice to a single neonatal (day P3) dose of UVB without additional chemical promotion. Indeed, there was a significant increase in the development of dermal spindle/epithelioid cell melanomas in Xpc-/-Ink4a-Arf-/- mice when compared with Xpc+/+Ink4a-Arf-/- mice (P = 0.005); wild-type and Xpc-/-Ink4a-Arf+/+ mice failed to develop tumors. These neoplasms bore a striking histologic resemblance to melanomas that arise in the Tyr-vHRAS/Ink4a-Arf-/- context and often expressed melanocyte differentiation marker Tyrp1, thus supporting their melanocytic origination. All strains, except wild-type mice, developed pigmented and non-pigmented epidermal-derived keratinocytic cysts, whereas Xpc+/+Ink4a-Arf-/- mice exhibited the greatest propensity for squamous cell carcinoma development. We then screened for NRas, HRas, Kras, and BRaf mutations in tumor tissue and detected a higher frequency of rare Kras(Q61) alterations in tumors from Xpc-/-Ink4a-Arf-/- mice compared with Xpc+/+Ink4a-Arf-/- mice (50% versus 7%, P = 0.033). Taken together, results from this novel UV-inducible melanoma model suggest that NER loss, in conjunction with Ink4a-Arf inactivation, can drive melanoma photocarcinogenesis possibly through signature Kras mutagenesis.

Epigenetic silencing of novel tumor suppressors in malignant melanoma.

Malignant melanoma is a common and frequently lethal disease. Current therapeutic interventions have little effect on survival, emphasizing the need for a better understanding of the genetic, epigenetic, and phenotypic changes in melanoma formation and progression. We identified 17 genes that were not previously known to be silenced by methylation in melanoma using a microarray-based screen following treatment of melanoma cell lines with the DNA methylation inhibitor 5-Aza-2'-deoxycytidine. Eight of these genes have not been previously shown to undergo DNA methylation in any form of cancer. Three of the genes, QPCT, CYP1B1, and LXN, are densely methylated in >95% of uncultured melanoma tumor samples. Reexpression of either of two of the silenced genes, HOXB13 and SYK, resulted in reduced colony formation in vitro and diminished tumor formation in vivo, indicating that these genes function as tumor suppressors in melanoma.

Characterization of melanocyte-specific inducible Cre recombinase transgenic mice.

Conditional Cre-mediated recombination has emerged as a robust method of introducing somatic genetic alterations in an organ-specific manner in the mouse. Here, we generated and characterized mice harboring a 4-hydroxytamoxifen (OHT)-inducible Cre recombinase-estrogen receptor fusion transgene under the control of the melanocyte-specific tyrosinase promoter, designated Tyr::CreER(T2). Cre-mediated recombination was induced in melanocytes in a spatially and temporally controlled manner upon administration of OHT and was documented in embryonic melanoblasts, follicular bulb melanocytes, dermal dendritic melanocytes, epidermal melanocytes of tail skin, and in putative melanocyte stem cells located within the follicular bulge. Functional evidence suggestive of recombination in follicular melanocyte stem cells included the presence of Cre-mediated recombination in follicular bulb melanocytes 1 year after topical OHT administration, by which time several hair cycles have elapsed and the melanocytes residing in this location have undergone multiple rounds of apoptosis and replenishment. These Tyr:: CreER(T2) transgenic mice represent a useful resource for the evaluation of melanocyte developmental genetics, the characterization of melanocyte stem cell function and dynamics, and the construction of refined mouse models of malignant melanoma.

FLT3 internal tandem duplication mutations induce myeloproliferative or lymphoid disease in a transgenic mouse model.

Activating FMS-like tyrosine kinase 3 (FLT3) mutations have been identified in approximately 30% of patients with acute myelogenous leukemia (AML), and recently in a smaller subset of patients with acute lymphoblastic leukemia (ALL). To explore the in vivo consequences of an activating FLT3 internal tandem duplication mutation (FLT3-ITD), we created a transgenic mouse model in which FLT3-ITD was expressed under the control of the vav hematopoietic promoter. Five independent lines of vav-FLT3-ITD transgenic mice developed a myeloproliferative disease with high penetrance and a disease latency of 6-12 months. The phenotype was characterized by splenomegaly, megakaryocytic hyperplasia, and marked thrombocythemia, but without leukocytosis, polycythemia, or marrow fibrosis, displaying features reminiscent of the human disease essential thrombocythemia (ET). Clonal immature B- or T-lymphoid disease was observed in two additional founder mice, respectively, that could be secondarily transplanted to recipient mice that rapidly developed lymphoid disease. Treatment of these mice with the FLT3 tyrosine kinase inhibitor, PKC412, resulted in suppression of disease and a statistically significant prolongation of survival. These results demonstrate that FLT3-ITD is capable of inducing myeloproliferative as well as lymphoid disease, and indicate that small-molecule tyrosine kinase inhibitors may be an effective treatment for lymphoid malignancies in humans that are associated with activating mutations in FLT3.

Loss of Runx1 perturbs adult hematopoiesis and is associated with a myeloproliferative phenotype.

Homozygous loss of function of Runx1 (Runt-related transcription factor 1 gene) during murine development results in an embryonic lethal phenotype characterized by a complete lack of definitive hematopoiesis. In light of recent reports of disparate requirements for hematopoietic transcription factors during development as opposed to adult hematopoiesis, we used a conditional gene-targeting strategy to effect the loss of Runx1 function in adult mice. In contrast with the critical role of Runx1 during development, Runx1 was not essential for hematopoiesis in the adult hematopoietic compartment, though a number of significant hematopoietic abnormalities were observed. Runx1 excision had lineage-specific effects on B- and T-cell maturation and pronounced inhibition of common lymphocyte progenitor production. Runx1 excision also resulted in inefficient platelet production. Of note, Runx1-deficient mice developed a mild myeloproliferative phenotype characterized by an increase in peripheral blood neutrophils, an increase in myeloid progenitor populations, and extramedullary hematopoiesis composed of maturing myeloid and erythroid elements. These findings indicate that Runx1 deficiency has markedly different consequences during development compared with adult hematopoiesis, and they provide insight into the phenotypic manifestations of Runx1 deficiency in hematopoietic malignancies.

MOZ-TIF2, but not BCR-ABL, confers properties of leukemic stem cells to committed murine hematopoietic progenitors.

To better understand the origin of leukemic stem cells, we tested the hypothesis that all leukemia oncogenes could transform committed myeloid progenitor cells lacking the capacity for self-renewal, as has recently been reported for MLL-ENL. Flow-sorted populations of common myeloid progenitors and granulocyte-monocyte progenitors were transduced with the oncogenes MOZ-TIF2 and BCR-ABL, respectively. MOZ-TIF2-transduced progenitors could be serially replated in methylcellulose cultures and continuously propagated in liquid culture, and resulted in an acute myeloid leukemia in vivo that could be serially transplanted. In contrast, BCR-ABL transduction conferred none of these properties to hematopoietic progenitors. These data demonstrate that some, but not all, leukemia oncogenes can confer properties of leukemic stem cells to hematopoietic progenitors destined to undergo apoptotic cell death.

Variable sensitivity of FLT3 activation loop mutations to the small molecule tyrosine kinase inhibitor MLN518.

FLT3 is constitutively activated by internal tandem duplications (ITDs) in the juxtamembrane domain or by activation loop mutations in acute myeloid leukemia (AML). We tested the sensitivity of 8 activation loop mutations to the small molecule FLT3 inhibitor, MLN518. Each FLT3 activation loop mutant, including D835Y, D835A, D835E, D835H, D835N, D835V, D835del, and I836del, transformed Ba/F3 cells to factor-independent proliferation and had constitutive tyrosine kinase activation, as assessed by FLT3 autophosphorylation and activation of downstream effectors, including STAT5 and ERK. MLN518 inhibited FLT3 autophosphorylation and phosphorylation of STAT5 and ERK in FLT3-ITD-transformed Ba/F3 cells with an IC(50) (50% inhibition of cell viability) of approximately 500 nM. However, there was a broad spectrum of sensitivity among the 8 activation loop mutants, with IC(50) ranging from approximately 500 nM to more than 10 microM for the inhibition of phosphorylation of FLT3, STAT5, and ERK. The relative sensitivity of the mutants to MLN518 in biochemical assays correlated with the cellular IC(50) for cytokine-independent proliferation of FLT3-transformed Ba/F3 cells in the presence of MLN518. Thus, certain activation loop mutations in FLT3 simultaneously confer resistance to small molecule inhibitors. These findings have implications for the evaluation of responses in clinical trials with FLT3 inhibitors and provide a strategy to screen for compounds that can overcome resistance.

PKC412 overcomes resistance to imatinib in a murine model of FIP1L1-PDGFRα-induced myeloproliferative disease.

FIP1L1-PDGFRalpha causes hypereosinophilic syndrome (HES) and is inhibited by the tyrosine kinase inhibitor imatinib (Gleevec). Imatinib is a potent inhibitor of ABL, ARG, PDGFRalpha, PDGFRbeta, and KIT and induces durable hematologic responses in HES patients. However, we observed relapse with resistance to imatinib as consequence of a T674I mutation in FIP1L1-PDGFRalpha, analogous to the imatinib-resistant T315I mutation in BCR-ABL. We developed a murine bone marrow transplant model of FIP1L1-PDGFRalpha-induced myeloproliferative disease to evaluate the efficacy of PKC412, an alternative inhibitor of PDGFRalpha, for the treatment of HES. PKC412 is effective for treatment of FIP1L1-PDGFRalpha-induced disease and of imatinib-induced resistance due to the T674I mutation. Our data establish PKC412 as molecularly targeted therapy for HES and other diseases expressing activated PDGFRalpha and demonstrate the potential of alternative kinase inhibitors to overcome resistance in target tyrosine kinases.