The development and validation of an early warning system to prevent the acquisition of 12-lead resting ECGs with interchanged electrode positions.

BACKGROUND: A fraction of routine resting ECG's are taken with electrode positions interchanged, leading to possible clinical misinterpretation. OBJECTIVE: Develop and test a method to detect and prevent electrode reversals at the electrocardiograph before the ECG is acquired. METHOD: The algorithm is based on QRS axis and P amplitudes for limb electrode reversals, and P-Q-RS amplitude distances to detect chest electrode reversals. The evaluation method involved a large (>18,000) hospital database for which serial ECG's were available and was based on simulated juxtapositions. RESULTS: The 7 most common lead reversals could be detected with a specificity of 99.8% per type and an average sensitivity of 90%, excluding LA-LL reversal (22% sensitivity). DISCUSSION: Results are similar to retrospective studies that used smaller, more homogeneous datasets. CONCLUSION: The early warning system reduces the ECG's recorded with reversal by 80%, at the price of a modest false alert rate of 1.4%.

Diagnostic utility of cytokeratin 17 immunostaining in morpheaform basal cell carcinoma and for facilitating the detection of tumor cells at the surgical margins.

BACKGROUND: The morpheaform subtype of basal cell carcinoma (BCC) often presents a diagnostic histological challenge, and its true margin may be difficult to determine with accuracy. This tumor may also be difficult to distinguish from other adnexal neoplasms having a benign clinical course. Previous work has shown that cytokeratin 17 (CK17 or K17) expression is high in BCC. OBJECTIVE: To confirm the expression of K17 across the subtypes of superficial, nodular and morpheaform BCC variants and to compare K17 expression in each of these subtypes of BCC with that in two other adnexal neoplasms. METHODS: Tissue specimens from each tumor category were randomly collected, immunolabeled, and scored for K17 expression according to intensity and extent of immunostaining. RESULTS: Our results indicate that K17 is a useful marker in the identification and outlining of BCC. Moreover, in morpheaform BCC, K17 immunostaining clearly detected individual tumor cells well away from the dermal tumor strands that otherwise seemed nonmalignant according to hematoxylin and eosin staining alone. In addition, the expression of K17 in morpheaform BCC is capable (100% of specimens; p < .001) of distinguishing this tumor from desmoplastic trichoepithelioma. CONCLUSION: We propose that K17 immunostaining could improve the diagnostic and surgical management of these tumors.

Cutaneous Rosai-Dorfman disease.

Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a benign disorder of histiocyte proliferation that usually affects the lymph nodes. Cutaneous Rosai-Dorfman disease (CRDD) is a rare extranodal variant that is strictly limited to the skin. We report a patient with CRDD of the trunk. A brief review of the literature of CRDD also is provided.

The utility of the DNA microarray scanner to simplify the immunofluorescence evaluation of autoimmune bullous diseases.

A DNA microarray scanner was used as a digital fluorescence microscope to simplify the diagnosis of autoimmune bullous diseases. Frozen sections of skin biopsies were taken from 3 patients with bullous pemphigoid and 1 patient each with lichen planus pemphigoides, linear immunoglobulin (Ig) A disease, and dermatitis herpetiformis. After incubation with cyanine-labeled antibodies, the tissues were scanned at 5-mum resolution using an instrument originally designed to study gene expression. The microarray scanner's large field of view, unlike that of fluorescence microscopy, allowed a view of the entire specimen, considerably easing the orientation of tissue. All images were diagnostic and included a linear pattern along the basement membrane zone (BMZ) using anti-IgG and anti-C3 in all cases of bullous pemphigoid, a linear pattern of IgG along the BMZ in lichen planus pemphigoides, and a linear pattern of IgA along the BMZ in linear IgA dermatosis. IgA deposition along dermal papillary tips was seen in dermatitis herpetiformis, but a granular pattern was indiscernible at the 5-mum resolution. The advantages of the microarray scanner over standard fluorescence microscopy include speed, technical ease, large field of view, potential for visualizing multiple antibodies simultaneously in a tissue, and convenience of digital image archiving.

Distinct effector-binding sites enable synergistic transcriptional activation by BenM, a LysR-type regulator.

BenM, a bacterial transcriptional regulator, responds synergistically to two effectors, benzoate and cis,cis-muconate. CatM, a paralog with overlapping function, responds only to muconate. Structures of their effector-binding domains revealed two effector-binding sites in BenM. BenM and CatM are the first LysR-type regulators to be structurally characterized while bound with physiologically relevant exogenous inducers. The effector complexes were obtained by soaking crystals with stabilizing solutions containing high effector concentrations and minimal amounts of competing ions. This strategy, including data collection with fragments of fractured crystals, may be generally applicable to related proteins. In BenM and CatM, the binding of muconate to an interdomain pocket was facilitated by helix dipoles that provide charge stabilization. In BenM, benzoate also bound in an adjacent hydrophobic region where it alters the effect of muconate bound in the primary site. A charge relay system within the BenM protein appears to underlie synergistic transcriptional activation. According to this model, Glu162 is a pivotal residue that forms salt-bridges with different arginine residues depending on the occupancy of the secondary effector-binding site. Glu162 interacts with Arg160 in the absence of benzoate and with Arg146 when benzoate is bound. This latter interaction enhances the negative charge of muconate bound to the adjacent primary effector-binding site. The redistribution of the electrostatic potential draws two domains of the protein more closely towards muconate, with the movement mediated by the dipole moments of four alpha helices. Therefore, with both effectors, BenM achieves a unique conformation capable of high level transcriptional activation.

Simulation Training for In-Flight Medical Emergencies Improves Provider Knowledge and Confidence.

INTRODUCTION: In-flight medical emergencies require healthcare providers to operate in confined spaces with limited resources and delayed access to definitive care. These emergencies are common, with an estimated frequency of 1 per 100 to 1000 flights. Despite this, training for medical response in these environments is limited. We hypothesize that integrating such education into a pre-existing medical student elective course would improve knowledge and ability to respond appropriately to in-flight medical emergencies.METHODS: The available literature surrounding in-flight medical emergencies was reviewed. Syncope, respiratory distress, allergic reaction, and cardiac arrest were identified as common and potentially life-threatening complaints. Simulation cases were designed for each of these complaints and a simulation room was modified to mimic an airplane cabin. These simulation cases and accompanying relevant didactic lectures were incorporated into an existing wilderness and extreme environmental medicine course, with multiple-choice tests completed by the students at the beginning and end of the 2-wk course.RESULTS: Participating in this study were 18 students. The pretest average was 76%, which improved to 87% on the posttest. Qualitative feedback regarding this type of training was overwhelmingly positive.DISCUSSION: Simulation-based training for in-flight medical emergencies can significantly improve medical students' knowledge. This training was very well received by the students. Opportunities for training to manage in-flight medical emergencies remain limited; incorporating such training into existing curricula could provide a means by which to improve provider knowledge. Such a curriculum could be adapted for use by flight crews and other populations.Padaki A, Redha W, Clark T, Nichols T, Jacoby L, Slivka R, Ranniger C, Lehnhardt K. Simulation training for in-flight medical emergencies improves provider knowledge and confidence. Aerosp Med Hum Perform. 2018; 89(12):1076-1079.

Realtime nowcasting with a Bayesian mixed frequency model with stochastic volatility.

The paper develops a method for producing current quarter forecasts of gross domestic product growth with a (possibly large) range of available within-the-quarter monthly observations of economic indicators, such as employment and industrial production, and financial indicators, such as stock prices and interest rates. In light of existing evidence of time variation in the variances of shocks to gross domestic product, we consider versions of the model with both constant variances and stochastic volatility. We use Bayesian methods to estimate the model, to facilitate providing shrinkage on the (possibly large) set of model parameters and conveniently generate predictive densities. We provide results on the accuracy of nowcasts of realtime gross domestic product growth in the USA from 1985 through 2011. In terms of point forecasts, our proposal improves significantly on auto-regressive models and performs comparably with survey forecasts. In addition, it provides reliable density forecasts, for which the stochastic volatility specification is quite useful.

The benPK operon, proposed to play a role in transport, is part of a regulon for benzoate catabolism in Acinetobacter sp. strain ADP1.

BenM and CatM are distinct, but similar, LysR-type transcriptional regulators of the soil bacterium Acinetobacter sp. strain ADP1. Together, the two regulators control the expression of at least 14 genes involved in the degradation of aromatic compounds via the catechol branch of the beta-ketoadipate pathway. In these studies, BenM and CatM were each purified to homogeneity to test the possibility that they regulate the expression of two additional genes, benP and benK, that are adjacent to benM on the chromosome. Each regulator bound to a DNA fragment containing the benP promoter region. Additional transcriptional studies suggested that benP and benK are co-transcribed as an operon, and a site of transcription initiation was identified. Alignment of this initiation site with those of several CatM- and BenM-regulated genes revealed common regulatory motifs. Mutants lacking both CatM and BenM failed to activate benP transcription. The ability of each protein to regulate gene expression was inferred from strains lacking either CatM or BenM that were still capable of increasing benP expression in response to cis,cis-muconate. This compound has previously been shown to induce all enzymes of the catechol branch of the beta-ketoadipate pathway through a complex transcriptional circuit involving CatM and BenM. Thus, the regulated expression of the benPK operon in concert with other genes of the regulon is consistent with the model that BenP, a putative outer-membrane porin, and BenK, an inner-membrane permease, transport aromatic compounds in strain ADP1.

Crystallization of the effector-binding domains of BenM and CatM, LysR-type transcriptional regulators from Acinetobacter sp. ADP1.

BenM, a member of the LysR-type family of transcriptional regulators, controls genes for benzoate degradation in the Gram-negative bacterium Acinetobacter sp. strain ADP1. Recent studies show that BenM activates benABCDE expression synergistically in response to two effector ligands: cis,cis-muconate (CCM) and benzoate. As an initial step in investigating the structural basis of dual effector response, the effector-binding domain of BenM (BenM-EBD) was crystallized by the microbatch-under-oil technique with conditions optimized from high-throughput screens performed by the Hauptman-Woodward Institute. Data-collection quality crystals of BenM-EBD belonged to space group P2(1)2(1)2(1), diffracted to 2.3 A and had unit-cell parameters a = 65.64, b = 66.34, c = 117.46 A. The influence of effector ligands on crystal formation was also evaluated. The presence of benzoate or CCM impaired the formation of crystals. The presence of both effectors together resulted in a dramatic decrease in the production of crystals. The effector-binding domain of CatM, a homolog of BenM, was also crystallized.

Transcriptional cross-regulation of the catechol and protocatechuate branches of the beta-ketoadipate pathway contributes to carbon source-dependent expression of the Acinetobacter sp. strain ADP1 pobA gene.

Transcriptional control of carbon source preferences by Acinetobacter sp. strain ADP1 was assessed with a pobA::lacZ fusion during growth on alternative substrates. The pobA-encoded enzyme catalyzes the first step in the degradation of 4-hydroxybenzoate, a compound consumed rapidly as a sole carbon source. If additional aromatic carbon sources are available, 4-hydroxybenzoate consumption is inhibited by unknown mechanisms. As reported here, during growth on aromatic substrates, pobA was not expressed despite the presence of 4-hydroxybenzoate, an inducer that normally causes the PobR regulator to activate pobA transcription. Growth on organic acids such as succinate, fumarate, and acetate allowed higher levels of pobA expression. In each case, pobA expression increased at the end of the exponential growth phase. Complex transcriptional regulation controlled 4-hydroxybenzoate catabolism in multisubstrate environments. Additional studies focused on the wild-type preference for benzoate consumption prior to 4-hydroxybenzoate consumption. These compounds are degraded via the catechol and protocatechuate branches of the beta-ketoadipate pathway, respectively. Here, mutants were characterized that degraded benzoate and 4-hydroxybenzoate concurrently. These mutants lacked the BenM and CatM transcriptional regulators that normally activate genes for benzoate catabolism. A model is presented in which BenM and CatM prevent pobA expression indirectly during growth on benzoate. These regulators may affect pobA expression by lowering the PcaK-mediated uptake of 4-hydroxybenzoate. Consistent with this model, BenM and CatM bound in vitro to an operator-promoter fragment controlling the expression of several pca genes, including pcaK. These studies provide the first direct evidence of transcriptional cross-regulation between the distinct but analogous branches of the beta-ketoadipate pathway.

Benzoate decreases the binding of cis,cis-muconate to the BenM regulator despite the synergistic effect of both compounds on transcriptional activation.

Fluorescence emission spectroscopy was used to investigate interactions between two effectors and BenM, a transcriptional regulator of benzoate catabolism. BenM had a higher affinity for cis,cis-muconate than for benzoate as the sole effector. However, the presence of benzoate increased the apparent dissociation constant (reduced the affinity) of the protein for cis,cis-muconate. Similar results were obtained with truncated BenM lacking the DNA-binding domain. High-level transcriptional activation may require that some monomers within a BenM tetramer bind benzoate and others bind cis,cis-muconate.