Epidermolytic Ichthyosis Sine Epidermolysis.

Epidermolytic ichthyosis (EI) is a rare disorder of cornification caused by mutations in KRT1 and KRT10, encoding two suprabasal epidermal keratins. Because of the variable clinical features and severity of the disease, histopathology is often required to correctly direct the molecular analysis. EI is characterized by hyperkeratosis and vacuolar degeneration of the upper epidermis, also known as epidermolytic hyperkeratosis, hence the name of the disease. In the current report, the authors describe members of 2 families presenting with clinical features consistent with EI. The patients were shown to carry classical mutations in KRT1 or KRT10, but did not display epidermolytic changes on histology. These observations underscore the need to remain aware of the limitations of pathological features when considering a diagnosis of EI.

Different roles of cadherins in the assembly and structural integrity of the desmosome complex.

Adhesion between cells is established by the formation of specialized intercellular junctional complexes, such as desmosomes. Desmosomes contain isoforms of two members of the cadherin superfamily of cell adhesion proteins, desmocollins (Dsc) and desmogleins (Dsg), but their combinatorial roles in desmosome assembly are not understood. To uncouple desmosome assembly from other cell-cell adhesion complexes, we used micro-patterned substrates of Dsc2aFc and/or Dsg2Fc and collagen IV; we show that Dsc2aFc, but not Dsg2Fc, was necessary and sufficient to recruit desmosome-specific desmoplakin into desmosome puncta and produce strong adhesive binding. Single-molecule force spectroscopy showed that monomeric Dsc2a, but not Dsg2, formed Ca(2+)-dependent homophilic bonds, and that Dsg2 formed Ca(2+)-independent heterophilic bonds with Dsc2a. A W2A mutation in Dsc2a inhibited Ca(2+)-dependent homophilic binding, similar to classical cadherins, and Dsc2aW2A, but not Dsg2W2A, was excluded from desmosomes in MDCK cells. These results indicate that Dsc2a, but not Dsg2, is required for desmosome assembly through homophilic Ca(2+)- and W2-dependent binding, and that Dsg2 might be involved later in regulating a switch to Ca(2+)-independent adhesion in mature desmosomes.

Severe dermatitis, multiple allergies, and metabolic wasting syndrome caused by a novel mutation in the N-terminal plakin domain of desmoplakin.

BACKGROUND: Severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome is a recently recognized syndrome caused by mutations in the desmoglein 1 gene (DSG1). To date, only 3 families have been reported. OBJECTIVE: We studied a new case of SAM syndrome known to have no mutations in DSG1 to detail the clinical, histopathologic, immunofluorescent, and ultrastructural phenotype and to identify the underlying molecular mechanisms in this rare genodermatosis. METHODS: Histopathologic, electron microscopy, and immunofluorescent studies were performed. Whole-exome sequencing data were interrogated for mutations in desmosomal and other skin structural genes, followed by Sanger sequencing of candidate genes in the patient and his parents. RESULTS: No mutations were identified in DSG1; however, a novel de novo heterozygous missense c.1757A>C mutation in the desmoplakin gene (DSP) was identified in the patient, predicting the amino acid substitution p.His586Pro in the desmoplakin polypeptide. CONCLUSIONS: SAM syndrome can be caused by mutations in both DSG1 and DSP. Knowledge of this genetic heterogeneity is important for both analysis of patients and genetic counseling of families. This condition and these observations reinforce the importance of heritable skin barrier defects, in this case desmosomal proteins, in the pathogenesis of atopic disease.

In vitro culture of Parascaris equorum larvae and initial investigation of parasite excretory-secretory products.

Currently, diagnosis of Parascaris equorum infection in equids is limited to patent infections. The goals of this study were to culture P. equorum larvae in vitro and identify excretory-secretory (ES) products for prepatent diagnostic testing. Parascaris equorum L2/L3 larvae were hatched and cultured for up to 3 weeks for ES product collection. Fifth stage (L5) P. equorum were also cultured for ES product collection. Examination of ES fractions by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and silver stain revealed L2/L3 products ranging from 12-94 kDa and L5 products ranging from 12-189 kDa. Western blot analyses were conducted using polyclonal antibodies produced against P. equorum or Baylisascaris procyonis L2/L3 ES products, sera from rabbits inoculated with B. procyonis or Toxocara canis eggs, and sera from animals naturally infected with P. equorum or T. canis. Western blot results indicated parasite antigens migrating at 19 and 34 kDa may be useful for specifically detecting P. equorum infections.

Institutionalizing the academic health department within the context of the 3-fold academic mission.

A mature model of an academic health department (AHD) that has been institutionalized over 2 decades is described within the context of the 3-fold traditional mission of academics (teaching, research, and service/practice). This adaptive model for AHDs, based on mutual benefits that can be viewed through the lenses of both the academic health center mission and the public health functions and services, has important implications for AHD sustainability. Continued collaboration in any academic-public health partnership will depend in part on the commitments of the changing leadership. However, institutionalizing support for the academic mission enables this collaboration to transcend changing leadership styles and priorities. The collaboration of Duval County Health Department and University of Florida College of Medicine-Jacksonville is an example of a model of AHD that has endured major changes in leadership within both the academic center and the Duval County Health Department.

Intrabiliary metastasis of colorectal mucinous adenocarcinoma mimicking choledocholithiasis 18 years after the primary tumor.

This case report presents a 62-year-old male who had previously undergone curative colectomy and neoadjuvant chemotherapy in 2005 for colorectal cancer. He presented with jaundice, which was initially attributed to choledocholithiasis. After cholecystectomy and repeat ERCPs, hyperbilirubinemia persisted. There was persistent dilation of the right posterior duct on imaging, concerning for biliary stricture, possibly due to cholangiocarcinoma or intraductal papillary neoplasm. During a right posterior hepatectomy, a peripheral liver lesion was found in association with the dilated bile duct. On frozen evaluation, the lesion was found to be invasive adenocarcinoma. The final pathology was compatible with a metastatic mucinous adenocarcinoma of colonic origin. A repeat colonoscopy was done with no recurrence or new lesion in the colon. This case underscores the challenges associated with diagnosing biliary issues and assessing liver lesions in patients with a remote history of cancer. It raises the question of when and whether, after primary cancer treatment, it becomes safe to explore alternative diagnoses without immediately suspecting metastasis. Another significant challenge arises in ascertaining the most suitable therapeutic approaches for these patients. This is because these extremely late recurrences might be linked to an indolent, slow-growing type of tumor, but also have been linked to cancer stem cells, and as any recurrence, demands attention.

Transcriptional profiling of rare acantholytic disorders suggests common mechanisms of pathogenesis.

Darier, Hailey-Hailey, and Grover diseases are rare acantholytic skin diseases. While these diseases have different underlying causes, they share defects in cell-cell adhesion in the epidermis and desmosome organization. To better understand the underlying mechanisms leading to disease in these conditions, we performed RNA-seq on lesional skin samples from patients. The transcriptomic profiles of Darier, Hailey-Hailey, and Grover diseases were found to share a remarkable overlap, which did not extend to other common inflammatory skin diseases. Analysis of enriched pathways showed a shared increase in keratinocyte differentiation, and a decrease in cell adhesion and actin organization pathways in Darier, Hailey-Hailey, and Grover diseases. Direct comparison to atopic dermatitis and psoriasis showed that the downregulation in actin organization pathways was a unique feature in the acantholytic skin diseases. Furthermore, upstream regulator analysis suggested that a decrease in SRF/MRTF activity was responsible for the downregulation of actin organization pathways. Staining for MRTFA in lesional skin samples showed a decrease in nuclear MRTFA in patient skin compared with normal skin. These findings highlight the significant level of similarity in the transcriptome of Darier, Hailey-Hailey, and Grover diseases, and identify decreases in actin organization pathways as a unique signature present in these conditions.

Dia1 coordinates differentiation and cell sorting in a stratified epithelium.

Although implicated in adhesion, only a few studies address how the actin assembly factors guide cell positioning in multicellular tissues. The formin, Dia1, localizes to the proliferative basal layer of the epidermis. In organotypic cultures, Dia1 depletion reduced basal cell density and resulted in stratified tissues with disorganized differentiation and proliferative markers. Since crowding induces differentiation in epidermal tissues, we hypothesized that Dia1 is essential to reach densities amenable to differentiation before or during stratification. Consistent with this, forced crowding of Dia1-deficient cells rescued transcriptional abnormalities. We find Dia1 promotes rapid growth of lateral cell-cell adhesions, necessary for the construction of a highly crowded monolayer. In aggregation assays, cells sorted into distinct layers based on Dia1 expression status. These results suggest that as basal cells proliferate, reintegration and packing of Dia1-positive daughter cells is favored, whereas Dia1-negative cells tend to delaminate to a suprabasal compartment. This work elucidates the role of formin expression patterns in constructing distinct cellular domains within stratified epithelia.

Gastrointestinal vaso-occlusive crisis in sickle cell disease.

Although rare, gastrointestinal vaso-occlusive crisis in sickle cell disease results in potentially life-threatening ischemia and death. Here we present a case of a 34-year-old patient with sickle cell disease who developed an acute pain crisis complicated by hypovolemia, hypoxia, and hypotension. The patient was treated with supportive measures. Diagnosis can be challenging and difficult to differentiate from usual pain crisis.

Force-dependent intercellular adhesion strengthening underlies asymmetric adherens junction contraction.

Tissue morphogenesis arises from the culmination of changes in cell-cell junction length. Mechanochemical signaling in the form of RhoA underlies these ratcheted contractions, which occur asymmetrically. The underlying mechanisms of asymmetry remain unknown. We use optogenetically controlled RhoA in model epithelia together with biophysical modeling to uncover the mechanism lending to asymmetric vertex motion. Using optogenetic and pharmacological approaches, we find that both local and global RhoA activation can drive asymmetric junction contraction in the absence of tissue-scale patterning. We find that standard vertex models with homogeneous junction properties are insufficient to recapitulate the observed junction dynamics. Furthermore, these experiments reveal a local coupling of RhoA activation with E-cadherin accumulation. This motivates a coupling of RhoA-mediated increases in tension and E-cadherin-mediated adhesion strengthening. We then demonstrate that incorporating this force-sensitive adhesion strengthening into a continuum model is successful in capturing the observed junction dynamics. Thus, we find that a force-dependent intercellular "clutch" at tricellular vertices stabilizes vertex motion under increasing tension and is sufficient to generate asymmetries in junction contraction.

Tissue and liquid biopsy profiling reveal convergent tumor evolution and therapy evasion in breast cancer.

Pathological and genomic profiling have transformed breast cancer care by matching patients to targeted treatments. However, tumors evolve and evade therapeutic interventions often through the acquisition of genomic mutations. Here we examine patients profiled with tissue (TBx) and liquid biopsy (LBx) as part of routine clinical care, to characterize the tumor evolutionary landscape and identify potential vulnerabilities in the relapsed setting. Real-world evidence demonstrates that LBx is utilized later in care and identifies associations with intervening therapy. While driver events are frequently shared, acquired LBx alterations are detected in a majority of patients, with the highest frequency in ER+ disease and in patients with longer biopsy intervals. Acquired mutations are often polyclonal and present at lower allelic fractions, suggesting multi-clonal convergent evolution. In addition to well-characterized resistance mutations (e.g., ESR1, NF1, RB1, ERBB2), we observe a diversity of rarer but potentially targetable mutations (e.g., PIK3CA, HRAS/NRAS/KRAS, FGFR1/2/3, BRAF) and fusions (e.g., FGFR1/2, ERBB2, RET), as well as BRCA1/2 reversions through a variety of mechanisms, including splice alterations and structural deletions. This study provides insights on treatment and selection-driven tumor evolution and identifies potential combinatorial treatment options in advanced breast cancer.

Utility of electrodiagnostic testing in evaluating patients with lumbosacral radiculopathy: An evidence-based review.

This is an evidence-based review of electrodiagnostic (EDX) testing of patients with suspected lumbosacral radiculopathy to determine its utility in diagnosis and prognosis. Literature searches were performed to identify articles applying EDX techniques to patients with suspected lumbosacral radiculopathy. From the 355 articles initially discovered, 119 articles describing nerve conduction studies, electromyography (EMG), or evoked potentials in adequate detail were reviewed further. Fifty-three studies met inclusion criteria and were graded using predetermined criteria for classification of evidence for diagnostic studies. Two class II, 7 class III, and 34 class IV studies described the diagnostic use of EDX. One class II and three class III articles described H-reflexes with acceptable statistical significance for use in the diagnosis and confirmation of suspected S1 lumbosacral radiculopathy. Two class II and two class III studies demonstrated a range of sensitivities for use of muscle paraspinal mapping. Two class II studies demonstrated the utility of peripheral myotomal limb electromyography in radiculopathies.

The Role of Desmoglein 1 in Gap Junction Turnover Revealed through the Study of SAM Syndrome.

An effective epidermal barrier requires structural and functional integration of adherens junctions, tight junctions, gap junctions (GJ), and desmosomes. Desmosomes govern epidermal integrity while GJs facilitate small molecule transfer across cell membranes. Some patients with severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome, caused by biallelic desmoglein 1 (DSG1) mutations, exhibit skin lesions reminiscent of erythrokeratodermia variabilis, caused by mutations in connexin (Cx) genes. We, therefore, examined whether SAM syndrome-causing DSG1 mutations interfere with Cx expression and GJ function. Lesional skin biopsies from SAM syndrome patients (n = 7) revealed decreased Dsg1 and Cx43 plasma membrane localization compared with control and nonlesional skin. Cultured keratinocytes and organotypic skin equivalents depleted of Dsg1 exhibited reduced Cx43 expression, rescued upon re-introduction of wild-type Dsg1, but not Dsg1 constructs modeling SAM syndrome-causing mutations. Ectopic Dsg1 expression increased cell-cell dye transfer, which Cx43 silencing inhibited, suggesting that Dsg1 promotes GJ function through Cx43. As GJA1 gene expression was not decreased upon Dsg1 loss, we hypothesized that Cx43 reduction was due to enhanced protein degradation. Supporting this, PKC-dependent Cx43 S368 phosphorylation, which signals Cx43 turnover, increased after Dsg1 depletion, while lysosomal inhibition restored Cx43 levels. These data reveal a role for Dsg1 in regulating epidermal Cx43 turnover.

Characterization of a novel model for investigation of radiocontrast nephrotoxicity.

OBJECTIVES: Radiocontrast agents are one of the most common causes of acute renal failure in the world. These agents are required for both diagnostic and therapeutic modalities of medical intervention, including computed tomography (CT), angiography and cardiac catheterization. Publications over the past 40 years support three potential mechanisms of toxicity: oxidative stress, haemodynamics and hyperosmolar effects. An in vitro model provides a rapid evaluation of cellular toxicity without the complications of haemodynamics. This study evaluated the renal toxicity of radiocontrast agents at clinically relevant concentrations. METHODS: This study investigated the toxicity of two radiocontrast agents, diatrizoic acid (DA) and iothalamic acid (IA), using an in vitro model. Renal cortical slices isolated from F344 rats were incubated with 0-111 mg I/ml DA or IA. RESULTS: Renal slices exposed to DA and IA showed toxicity as measured by increased lactate dehydrogenase (LDH) leakage at concentrations lower than previously published using isolated cell models. These data indicate that DA and IA are toxic to renal cortical slices, and this is a more sensitive model than previously used cell culture systems. DA and IA treatment failed to cause a significant decrease in total cellular glutathione or increase in percent glutathione disulphide (GSSG), implying that oxidative stress may not be an initial mechanism of toxicity. Finally, the addition of exogenous glutathione did provide complete protection from DA- and IA-induced LDH leakage. CONCLUSION: These data validate the renal cortical slice in vitro model for investigation of radiocontrast nephrotoxicity. These studies further showed that glutathione was cytoprotective. Future research using this model is aimed at further characterization of radiocontrast nephrotoxicity, which may allow for improved prevention and treatment of radiocontrast-induced acute renal failure.

Resources That Improve Medical Board Licensing Examination Performance.

Purpose Examine the factors improving performance on national medical licensing board examinations. Rationale Accreditation Council for Graduate Medical Education (ACGME) accredited residency programs report the United States Medical Licensing Examination (USMLE) Step 1 and Comprehensive Osteopathic Licensing Examination-USA (COMLEX-USA) Level 1 scores as the most important criteria in selecting candidates to interview. Hypotheses (1) Certain resources are superior for exam preparation. (2) Certain practice tests better assess exam preparedness. (3) USMLE performance will correlate with the COMLEX-USA. Methods One-hundred and two (102) medical students were surveyed regarding preparation for and performance on COMLEX-USA Level 1 and USMLE Step 1. Results USMLE-specific question banks were positively correlated with performance on COMLEX-USA Level 1 and USMLE Step 1 while COMLEX-specific question banks showed no correlation. National Board of Medical Examiners (NBME) Comprehensive Basic Science Self Assessment (CBSSA) and National Board of Osteopathic Medical Examiners (NBOME) Comprehensive Osteopathic Medical Self-Assessment Examination (COMSAE) practice examinations were positively correlated with performance on the USMLE Step 1 and the COMLEX-USA Level 1. Scores on USMLE Step 1 and COMLEX-USA Level 1 were highly correlated. Students who took USMLE Step 1 performed better on COMLEX-USA Level 1 than those who did not. Conclusion COMLEX-specific resources may not adequately prepare students for COMLEX-USA Level 1. Students studying for COMLEX-USA Level 1 may benefit by preparing for USMLE Step 1.

Prevention and management of osteoporosis and osteoporotic fractures in persons with a spinal cord injury or disorder: A systematic scoping review.

Objectives: The primary objective was to review the literature regarding methodologies to assess fracture risk, to prevent and treat osteoporosis and to manage osteoporotic fractures in SCI/D.Study Design: Scoping review.Settings/Participants: Human adult subjects with a SCI/D.Outcome measures: Strategies to identify persons with SCI/D at risk for osteoporotic fractures, nonpharmacological and pharmacological therapies for osteoporosis and management of appendicular fractures.Results: 226 articles were included in the scoping review. Risk of osteoporotic fractures in SCI is predicted by a combination of DXA-defined low BMD plus clinical and demographic characteristics. Screening for secondary causes of osteoporosis, in particular hyperparathyroidism, hyperthyroidism, vitamin D insufficiency and hypogonadism, should be considered. Current antiresorptive therapies for treatment of osteoporosis have limited efficacy. Use of surgery to treat fractures has increased and outcomes are good and comparable to conservative treatment in most cases. A common adverse event following fracture was delayed healing.Conclusions: Most of the research in this area is limited by small sample sizes, weak study designs, and significant variation in populations studied. Future research needs to address cohort definition and study design issues.

Desmosomal cadherin association with Tctex-1 and cortactin-Arp2/3 drives perijunctional actin polymerization to promote keratinocyte delamination.

The epidermis is a multi-layered epithelium that serves as a barrier against water loss and environmental insults. Its morphogenesis occurs through a tightly regulated program of biochemical and architectural changes during which basal cells commit to differentiate and move towards the skin's surface. Here, we reveal an unexpected role for the vertebrate cadherin desmoglein 1 (Dsg1) in remodeling the actin cytoskeleton to promote the transit of basal cells into the suprabasal layer through a process of delamination, one mechanism of epidermal stratification. Actin remodeling requires the interaction of Dsg1 with the dynein light chain, Tctex-1 and the actin scaffolding protein, cortactin. We demonstrate that Tctex-1 ensures the correct membrane compartmentalization of Dsg1-containing desmosomes, allowing cortactin/Arp2/3-dependent perijunctional actin polymerization and decreasing tension at E-cadherin junctions to promote keratinocyte delamination. Moreover, Dsg1 is sufficient to enable simple epithelial cells to exit a monolayer to form a second layer, highlighting its morphogenetic potential.

Electronic health records in four community physician practices: impact on quality and cost of care.

OBJECTIVE: To assess the impact of the electronic health record (EHR) on cost (i.e., payments to providers) and process measures of quality of care. STUDY DESIGN: Retrospective before-after-study-control. From the database of a large managed care organization (MCO), we obtained the claims of patients from four community physician practices that implemented the EHR and from about 50 comparison practices without the EHR in the same counties. The diverse patient and practice populations were chosen to be a sample more representative of typical private practices than has previously been studied. MEASUREMENTS: For four chronic conditions, we used commercially-available software to analyze cost per episode over a year and the rate of adherence to clinical guidelines as a measure of quality. RESULTS: The implementation of the EHR had a modest positive impact on the quality measure of guideline adherence for hypertension and hyperlipidemia, but no significant impact for diabetes and coronary artery disease. No measurable impact on the short-term cost per episode was found. Discussions with the study practices revealed that the timing and comprehensiveness of EHR implementation varied across practices, creating an intervention variable that was heterogeneous. CONCLUSIONS: Guideline adherence increased across practices without EHRs and slightly faster in practices with EHRs. Measuring the impact of EHRs on cost per episode was challenging, because of the difficulty of completely capturing the long-term episodic costs of a chronic condition. Few practices associated with the study MCO had implemented EHRs in any form, much less utilizing standardized protocols.

Epidermal Growth Factor Receptor neddylation is regulated by a desmosomal-COP9 (Constitutive Photomorphogenesis 9) signalosome complex.

Cell junctions are scaffolds that integrate mechanical and chemical signaling. We previously showed that a desmosomal cadherin promotes keratinocyte differentiation in an adhesion-independent manner by dampening Epidermal Growth Factor Receptor (EGFR) activity. Here we identify a potential mechanism by which desmosomes assist the de-neddylating COP9 signalosome (CSN) in attenuating EGFR through an association between the Cops3 subunit of the CSN and desmosomal components, Desmoglein1 (Dsg1) and Desmoplakin (Dp), to promote epidermal differentiation. Silencing CSN or desmosome components shifts the balance of EGFR modifications from ubiquitination to neddylation, inhibiting EGFR dynamics in response to an acute ligand stimulus. A reciprocal relationship between loss of Dsg1 and neddylated EGFR was observed in a carcinoma model, consistent with a role in sustaining EGFR activity during tumor progression. Identification of this previously unrecognized function of the CSN in regulating EGFR neddylation has broad-reaching implications for understanding how homeostasis is achieved in regenerating epithelia.