Association of sedation and anesthesia on cognitive outcomes in very premature infants: a retrospective observational study.

PURPOSE: Cognitive outcomes in preterm infants may be adversely affected by use of sedation and anesthetic agents. We investigated the associations between anesthetics/sedatives and full-scale intelligence quotient (FSIQ) measured at 36 months corrected age (CA) in very preterm infants (born < 29 weeks gestational age). METHODS: This retrospective cohort study included preterm infants born at < 29 weeks of gestation between 1 January 2006 and 31 December 2012, whose cognitive outcomes were assessed at 36 months CA. Imputed and complete case univariable and adjusted multivariable linear regressions were used to investigate the associations between FSIQ [standardized to mean (standard deviation) 100 (15)] and exposure to volatile anesthetics, propofol, benzodiazepines, barbiturates, and ketamine. These agents were the subject of a 2016 warning from regulatory authorities in the USA recommending caution for administration to children and pregnant women. RESULTS: A total of 731 infants met the inclusion criteria. Unadjusted associations were -7 (95% confidence interval [CI], -10 to -4; P < 0.001) and -6 (95% CI, -10 to -3; P < 0.001) FSIQ points with exposure to warned medications using imputed and complete case analyses, respectively. Imputed and complete case adjusted associations between FSIQ and warned medications were -3 (95% CI, -7 to 0; P = 0.045) and -4 (95% CI, -8 to 0; P = 0.071) FSIQ points, respectively. Adjusted associations between volatile anesthetic exposure only and FSIQ were -3 (95% CI, -6 to 0; P = 0.072) and -5 (95% CI, -9 to -2; P = 0.004) FSIQ points using imputed and complete case data sets, respectively. FSIQ was not associated with opioid exposure. CONCLUSION: Exposure of very preterm infants to anesthetics/sedatives on the United States Food and Drug Administration warning list was associated with a decrease in FSIQ points at 36 months CA. There was no association between opioid exposure and FSIQ.

RéSUMé: OBJECTIF : L'utilization d'agents sédatifs et anesthésiques pourrait avoir une incidence défavorable sur l'évolution cognitive des nourrissons prématurés. Nous avons analysé les associations existantes entre les anesthésiques/sédatifs et le quotient d'intelligence global (QIg) mesuré à 36 mois d'âge corrigé (AC) chez des enfants nés grands prématurés (nés < 29 semaines d'âge gestationnel). MéTHODES: Cette étude de cohorte rétrospective a inclus des nourrissons prématurés nés avant 29 semaines d'âge gestationnel entre le 1er janvier 2006 et le 31 décembre 2012 et dont les critères d'évaluation cognitifs ont été évalués à 36 mois d'AC. Des régressions linéaires à une seule variable et multivariables ajustée, sur les cas imputés et sur les cas complets, ont été utilisées pour rechercher les associations entre le QIg (standardisé à la moyenne 100 [± écart-type] [15]) et l'exposition à des anesthésiques volatils, du propofol, des benzodiazépines, des barbituriques et de la kétamine. Ces molécules ont fait l'objet d'une mise en garde en 2016 par les autorités de réglementation aux États-Unis, recommandant la prudence concernant leur administration à des enfants et à des femmes enceintes. RéSULTATS: Un total de 731 nourrissons présentait les critères d'inclusion. Les associations non ajustées ont été de -7 (intervalle de confiance [IC] à 95 % : -10 à -4; P < 0,001) et -6 (IC à 95 % : -10 à -3; P < 0,001) points de QIg avec l'exposition aux médicaments sous avertissement en utilisant, respectivement, des analyses de cas imputés et de cas complets. Les associations ajustées de cas imputés et complets entre le QIg et les médicaments sous avertissement ont été, respectivement, de -3 (IC à 95 % : -7 à 0; P = 0,045) et -4 (IC à 95 % : -8 à 0; P = 0,071) points de QIg. Les associations ajustées entre l'exposition aux anesthésiques volatiles, uniquement, et le QIg ont été de -3 (IC à 95 % : -6 à 0; P = 0,072) et -5 (IC à 95 % : -9 à 2; P = 0,004) points de QIg en utilisant, respectivement, les ensembles de données des cas imputés et des cas complets. Le QIg n'a pas été associé à une exposition aux opioïdes. CONCLUSION: L'exposition des nourrissons grands prématurés aux anesthésiques/sédatifs figurant sur la liste d'avertissement de la Food and Drug Administration des États-Unis a été associée à une diminution des points de QIg à 36 mois d'AC. Il n'y a pas eu d'association entre l'exposition aux opioïdes et le QIg.

The Evolving Landscape of Lung Cancer Surgical Resection: An Update for Radiologists With Focus on Key Chest CT Findings.

Evolution of the multimodality management of early lung cancer, including progress in surgical techniques, has introduced the possibility of resection for lung cancer cases that historically were considered unresectable (e.g., select cases of T4 disease and oligometastatic disease). However, the TNM classification does not uniformly correlate with lung cancer operability and resectability. Radiologic evaluation is therefore critical in identifying patients' suitability to undergo lung cancer resection and in guiding the selection of a surgical approach from among a range of such approaches, including wedge resection, segmentectomy, lobectomy, bilobectomy, and pneumonectomy. The radiologist must understand the available surgical options, along with their advantages and disadvantages, and provide a report that includes critical information on tumor size, location, and extension and anatomic relations that may influence the surgical technique. Preoperative CT findings may also help predict expected postoperative lung function and the associated impact on the postoperative course of the patient. This article reviews the role of chest CT in the preoperative evaluation of lung cancer, focusing on the key CT findings that help direct surgical decision making in the context of an expanding range of patients who may be considered candidates for resection.

Pleuroparenchymal fibroelastosis in systemic sclerosis: prevalence and prognostic impact.

Interstitial lung disease (ILD) in systemic sclerosis (SSc) is a major cause of morbidity and mortality, mostly presenting as non-specific interstitial pneumonia. Little is known about the prevalence of pleuroparenchymal fibroelastosis (PPFE), a specific entity affecting the visceral pleura and subpleural parenchyma. We set out to estimate PPFE prevalence in two large cohorts of SSc patients and to assess its impact on survival and functional decline.A total of 359 SSc patients, derived from two referral centres in two different countries (UK and Italy), were included. The first available high-resolution computed tomography scan was independently evaluated by two radiologists blind to clinical information, to quantify ILD extent, freestanding bronchial abnormalities, and lobar percentage involvement of PPFE on a four-point categorical scale. Discordant scores were adjudicated by a third scorer. PPFE extent was further classified as limited (≤2/18) or extensive (>2/18). Results were evaluated against functional decline and mortality.The overall prevalence of PPFE in the combined SSc population was 18% (11% with extensive PPFE), with no substantial difference between the two cohorts. PPFE was significantly linked to free-standing bronchial abnormalities (61% versus 25% in PPFE versus no PPFE; p<0.0001) and to worse survival, independently of ILD severity or short-term lung function changes (HR 1.89, 95% CI 1.10-3.25; p=0.005).In the current study, we provide an exhaustive description of PPFE prevalence and clinical impact in the largest cohort of SSc subjects published so far. PPFE presence should be carefully considered, due to its significant prognostic implications.

Imaging Evaluation of Tracheobronchial Injuries.

Tracheobronchial injuries are a rare but potentially life-threatening cause of respiratory insufficiency, with high mortality rates. For patients with potentially survivable tracheobronchial injuries, imaging in the acute setting plays a key role in demonstrating the injuries and associated complications. The radiologist can improve outcomes by understanding typical injury patterns according to injury mechanism and the influence that imaging findings may have on treatment decisions. Chest radiography and cervical and thoracic CT are the mainstays of imaging in the acute setting and in follow-up, often as part of a whole-body trauma imaging series. The authors first consider the influence of normal tracheobronchial anatomy with regard to protective features, such as cartilaginous rings. They also discuss inherent points of vulnerability, such as points of relative fixation at the carina. A framework is then provided for understanding the typical distribution and morphology of tracheobronchial injuries according to cause. This includes penetrating, iatrogenic, and blunt force mechanisms, with consideration of potential complications. The authors highlight treatment strategies that require multidisciplinary collaboration, such as ventilation, minimizing injuries, and defining optimal surgical or nonsurgical treatment. ©RSNA, 2020.

Imaging of Diffuse Lung Disease in the Intensive Care Unit Patient.

There is a wide variety of causes of diffuse lung disease in the intensive care unit patient, of which adult respiratory distress syndrome is the commonest clinical consideration. Plain radiography, computed tomography, and ultrasound can be used synergistically to evaluate patients with diffuse lung disease and respiratory impairment. Imaging is not limited to characterization of the cause of diffuse lung disease but also aids in monitoring its evolution and in ventilator setting management.

Lung Cancers Associated with Cystic Airspaces: Underrecognized Features of Early Disease.

Early lung cancers associated with cystic airspaces are increasingly being recognized as a cause of delayed diagnoses-owing to data gathered from screening trials and encounters in routine clinical practice as more patients undergo serial imaging. Several morphologic subtypes of cancers associated with cystic airspaces exist and can exhibit variable patterns of progression as the solid elements of the tumor grow. Current understanding of the pathogenesis of these malignancies is limited, and the numbers of cases reported in the literature are small. However, several tumor cell types are represented in these lesions, with adenocarcinoma predominating. The features of cystic airspaces differ among cases and include emphysematous bullae, congenital or fibrotic cysts, subpleural blebs, bronchiectatic airways, and distended distal airspaces. Once identified, these cystic lesions pose management challenges to radiologists in terms of distinguishing them from benign mimics of cancer that are commonly seen in patients who also are at increased risk of lung cancer. Rendering a definitive tissue-based diagnosis can be difficult when the lesions are small, and affected patients tend to be in groups that are at higher risk of requiring biopsy or resection. In addition, the decision to monitor these cases can add to patient anxiety and cause the additional burden of strained departmental resources. The authors have drawn from their experience, emerging evidence from international lung cancer screening trials, and large databases of lung cancer cases from other groups to analyze the prevalence and evolution of lung cancers associated with cystic airspaces and provide guidance for managing these lesions. Although there are insufficient data to support specific management guidelines similar to those for managing small solid and ground-glass lung nodules, these data and guidelines should be the direction for ongoing research on early detection of lung cancer. ©RSNA, 2018.

Case Report: Post obstructive pulmonary edema (POPE) Type II following elective adenotonsillectomy requiring novel use of high frequency oscillatory ventilation (HFOV).

This case report describes a previously healthy 14 year-old patient undergoing elective outpatient adenotonsillectomy that was complicated by acute postoperative pulmonary edema requiring 12 hours of high frequency oscillatory ventilation (HFOV) support.  We describe the clinical findings that led us to this rare diagnosis and management of post obstructive pulmonary edema (POPE) Type II, a rare but recognized complication following the surgical relief of an upper airway obstruction. This case is unique in that no previously published case report or review of POPE Type II has described the need for HFOV support.

Anesthetic Neuroprotection in Experimental Stroke in Rodents: A Systematic Review and Meta-analysis.

BACKGROUND: Patients undergoing endovascular therapy for acute ischemic stroke may require general anesthesia to undergo the procedure. At present, there is little clinical evidence to guide the choice of anesthetic in this acute setting. The clinical implications of experimental studies demonstrating anesthetic neuroprotection are poorly understood. Here, the authors evaluated the impact of anesthetic treatment on neurologic outcome in experimental stroke. METHODS: Controlled studies of anesthetics in stroke using the filament occlusion model were identified in electronic databases up to December 15, 2015. The primary outcome measures, infarct volume, and neurologic deficit score were used to calculate the normalized mean difference for each comparison. Meta-analysis of normalized mean difference values provided estimates of neuroprotection and contributions of predefined factors: study quality, the timing of treatment, and the duration of ischemia. RESULTS: In 80 retrieved publications anesthetic treatment reduced neurologic injury by 28% (95% CI, 24 to 32%; P < 0.0001). Internal validity was high: publication bias enhanced the effect size by 4% or less, effect size increased with study quality (P = 0.0004), and approximately 70% of studies were adequately powered. Apart from study quality, no predefined factor influenced neuroprotection. Neuroprotection failed in animals with comorbidities. Neuroprotection by anesthetics was associated with prosurvival mechanisms. CONCLUSIONS: Anesthetic neuroprotection is a robust finding in studies using the filament occlusion model of ischemic stroke and should be assumed to influence outcomes in studies using this model. Neuroprotection failed in female animals and animals with comorbidities, suggesting that the results in young male animals may not reflect human stroke.

Iatrogenic peripheral pulmonary air embolism following intravenous contrast administration for CT pulmonary angiography: proposal of the "double bronchus sign".

We present a case of iatrogenic extensive air embolism in the peripheral pulmonary arterial tree following intravenous contrast injection for a CT pulmonary angiogram performed to investigate chest pain in a 25-year-old female patient. Small volumes of iatrogenic air embolism following contrast injection are not infrequently encountered incidentally in the central vasculature (brachiocephalic veins, superior vena cava, right cardiac chambers and main pulmonary arteries). To our knowledge, however, this is the only case of extensive peripheral pulmonary arterial air embolism on CT that has been reported in the literature. Despite the extent of peripheral air, this potentially clinically significant complication was relatively inconspicuous at CT interpretation. A new radiological sign, the "double bronchus sign", is proposed as a useful diagnostic tool. In addition to discussing the imaging features, important safety considerations and principles of immediate management, relevant to all radiologists, are addressed.

Evidence for Epigenetic Regulation of Gene Expression and Function in Chronic Experimental Diabetic Neuropathy.

Diabetic polyneuropathy (DPN) is a common but irreversible neurodegenerative complication of diabetes mellitus. Here we show that features of sensory neuron damage in mice with chronic DPN may have altered epigenetic micro RNA (miRNA) transcriptional control. We profiled sensory neuron messenger RNA and miRNA profiles in mice with type I diabetes mellitus and findings of DPN. Diabetic sensory dorsal root ganglia neurons showed a pattern of altered messenger RNA profiles associated with upregulated cytoplasmic sites of miRNA-mediated messenger RNA processing (GW/P bodies). Dorsal root ganglia miRNA microarray identified significant changes in expression among mice with diabetes, the most prominent of which were a 39% downregulation of mmu-let-7i and a 255% increase in mmu-miR-341; both were identified in sensory neurons. To counteract these alterations, we replenished let-7i miRNA by intranasal administration; in a separate experiment, we added an anti-miR that antagonized elevated mmu-341 after 5 months of diabetes. Both approaches independently improved electrophysiologic, structural, and behavioral abnormalities without altering hyperglycemia; control sequences did not have these effects. Dissociated adult sensory neurons exposed to an exogenous mmu-let-7i mimic displayed enhanced growth and branching, indicating a trophic action. These findings identify roles for epigenetic miRNA alterations and enhanced GW/P expression in diabetic dorsal root ganglia that contribute to the complex DPN phenotype.

A cross-sectional imaging study to identify organs at risk of thermal injury during renal artery sympathetic denervation.

BACKGROUND: The technology used to perform catheter-based renal artery sympathetic denervation has evolved: catheters can now access arteries as small as 3mm in diameter and create ablation zones of up to 10mm in depth. Recent evidence suggests that the procedure may be more effective if a more thorough ablation strategy is employed. Limited data are available regarding inadvertent soft tissue thermal injury during such procedures.  We used computed tomography (CT) to identify structures lying within the expected thermal ablation field or the 'at risk zone' (ARZ). METHODS: 63 consecutive CT aortograms were reviewed, yielding 100 renal arteries anatomically eligible for treatment. Structures lying within a predefined ARZ (within 10mm of the renal artery wall) were recorded. RESULTS: The 63 subjects had a mean age of 74.6years, 48% were males and 88% had hypertension.  The inferior vena cava and renal veins were in the ARZ in all cases.  Psoas muscles and small bowel were within the ARZ in at least a fifth of the kidneys. Other structures found in the ARZ included the liver, pancreas, adrenal glands and diaphragm. CONCLUSIONS: This study describes the variable anatomical relationship between renal arteries and important abdominal structures that may be exposed to thermal energy during modern denervation procedures.  The consequence of delivering such thermal energy to these structures is unknown but clinicians should be alert to the presenting symptoms if these structures are damaged. CT may have a pre-procedure role in assessing this risk.

99mTc-HDP SPECT-CT Aids Localization of Joint Injections in Degenerative Joint Disease of the Foot and Ankle.

BACKGROUND: Pain relating to degenerative joint disease within the foot and ankle can be difficult to localize with clinical examination alone due to the complex anatomy of the joints. The aim of this study was to determine whether single-photon emission computed tomography combined with conventional computed tomography (SPECT-CT) could be used to localize the site of degenerative joint disease for intra-articular injection and thereby improve the clinical success of the procedure. METHODS: A prospective study was performed involving 203 patients who had undergone triple-phase (99m)Tc-hydroxymethylene diphosphonate bone scans with SPECT-CT of the foot and ankle for degenerative joint disease. Fifty-two patients went on to have joint injections for degenerative joint disease, with clinical follow-up. Correlation with the clinical diagnosis and the outcome of intra-articular injections with 0.5% bupivacaine and 80 mg of Depo-Medrone was performed. A successful outcome was determined by an improvement in the visual analog pain score of at least 50%. RESULTS: In 19 (37%) patients, the site of degenerative joint disease determined by SPECT-CT differed from the initial clinical assessment and resulted in a change in management. Overall, 46 (88%) patients showed an improvement in symptoms. CONCLUSION: The study demonstrated a high clinical success rate for SPECT-CT-guided joint injections. The technique was useful in localizing degenerative joint disease of the ankle, hindfoot, and midfoot as an adjunct to clinical examination. LEVEL OF EVIDENCE: Level IV, case series.

Ultrastructural characterization of primary cilia in pathologically characterized human glioblastoma multiforme (GBM) tumors.

BACKGROUND: Primary cilia are non-motile sensory cytoplasmic organelles that are involved in cell cycle progression. Ultrastructurally, the primary cilium region is complex, with normal ciliogenesis progressing through five distinct morphological stages in human astrocytes. Defects in early stages of ciliogenesis are key features of astrocytoma/glioblastoma cell lines and provided the impetus for the current study which describes the morphology of primary cilia in molecularly characterized human glioblastoma multiforme (GBM) tumors. METHODS: Seven surgically resected human GBM tissue samples were molecularly characterized according to IDH1/2 mutation status, EGFR amplification status and MGMT promoter methylation status and were examined for primary cilia expression and structure using indirect immunofluorescence and electron microscopy. RESULTS: We report for the first time that primary cilia are disrupted in the early stages of ciliogenesis in human GBM tumors. We confirm that immature primary cilia and basal bodies/centrioles have aberrant ciliogenesis characteristics including absent paired vesicles, misshaped/swollen vesicular hats, abnormal configuration of distal appendages, and discontinuity of centriole microtubular blades. Additionally, the transition zone plate is able to form in the absence of paired vesicles on the distal end of the basal body and when a cilium progresses beyond the early stages of ciliogenesis, it has electron dense material clumped along the transition zone and a darkening of the microtubules at the proximal end of the cilium. CONCLUSIONS: Primary cilia play a role in a variety of human cancers. Previously primary cilia structure was perturbed in cultured cell lines derived from astrocytomas/glioblastomas; however there was always some question as to whether these findings were a cell culture phenomena. In this study we confirm that disruptions in ciliogenesis at early stages do occur in GBM tumors and that these ultrastructural findings bear resemblance to those previously observed in cell cultures. This is the first study to demonstrate that defects in cilia expression and function are a true hallmark of GBM tumors and correlate with their unrestrained growth. A review of the current ultrastructural profiles in the literature provides suggestions as to the best possible candidate protein that underlies defects in the early stages of ciliogenesis within GBM tumors.

A systematic review and quantitative analysis of neurocognitive outcomes in children with four chronic illnesses.

BACKGROUND: Concern has been expressed that infants and children exposed to uneventful surgery and anesthesia may incur neurological injury that becomes manifest in poor scholastic performance or future learning difficulties. A recent meta-analysis of seven clinical studies examined the relationship between learning or behavior difficulties and pediatric exposure to anesthesia/surgery and reported an odds ratio of 1.4; however, the level of association and causal factors remain unclear. The purpose of our study is to provide context to the pediatric anesthesia neurotoxicity question by reviewing the evidence linking four childhood illnesses with neurocognitive development. In the present review, we have sought to quantify the magnitude of the impact of chronic illness on neurocognitive development through a systematic review of publications that report the developmental trajectory of patients with four childhood diseases: cystic fibrosis (CF), hemophilia A, end-stage renal disease (ESRD) and end-stage liver disease (ESLD). METHODS: Studies were identified by searching the electronic databases OVID MEDLINE and Pubmed and scanning reference lists of articles by two authors. Limits were applied to the English language and to humans. We used the following search terms: CF, hemophilia A, ESRD, ESLD in combination with academic performance, educational status, educational measurement, learning, achievement, developmental delay, learning disabilities, intellectual disabilities, behavioral disorders, intelligence quotient (IQ), cognition, school problems, absenteeism, school attendance, anxiety, learning regression, or developmental regression. The search strategy was reviewed independently by all four authors. Eligibility assessment was performed independently in an unblinded standardized manner by two authors who chose relevant articles from the overall search results by scanning the titles and abstracts of articles and from the references within citations. The full-text publications were reviewed by all four authors. All pertinent data related to the objectives were collected and independently reviewed by two authors. The data were summarized in the form reported in the studies. When possible, reported data were submitted to analysis with the Mantel-Haenszel method using a random effects model. Analyses were performed using the Review Manager computer program. RESULTS: In the studies retrieved, the main outcomes were measures of intellectual or cognitive characteristics, as exemplified by the Wechsler battery of tests. Reporting of measures of achievement (for example, GPA) was rare. Children with CF and hemophilia A did not appear disadvantaged by their disease as general intelligence levels were comparable with the general population norms. In children with ESRD, mean IQ reported during dialysis improved after transplantation. Although they improved relative to their pretransplantation cognitive functioning, children with ESLD who received transplants are approximately eight IQ points below the population norm. CONCLUSIONS: Overall, the results suggest that the burden of chronic childhood illness, by itself, does not impair cognitive development in children with hemophilia A and CF. Children with ESRD and ESLD, despite optimal management, show a mild cognitive deficit compared with the population norm. Given the impact of these four specific chronic illnesses on neurocognitive outcome in children and the improvement in IQ post-transplant in both ESRD and ESLD, the results suggest that the effect of an uncontrolled confounding illness on neurocognitive development is small.

Relationship of other cytoplasmic ribonucleoprotein bodies (cRNPB) to GW/P bodies.

GW/P body components are involved in the post-transcriptional -processing of messenger RNA (mRNA) through the RNA interference and 5' → 3' mRNA degradation pathways, as well as functioning in mRNA transport and stabilization. It is currently thought that the relevant mRNA silencing and degrading factors are partitioned to these cytoplasmic microdomains thus effecting post-transcriptional regulation and the prevention of accidental degradation of functional mRNA. Although much attention has focused on GW/P bodies, a variety of other cytoplasmic RNP bodies (cRNPB) also have highly specialized functions and have been shown to interact or co-localize with components of GW/P bodies. These cRNPB include neuronal transport RNP granules, stress granules, RNP-rich cytoplasmic germline granules or chromatoid bodies, sponge bodies, cytoplasmic prion protein-induced RNP granules, U bodies and TAM bodies. Of clinical relevance, autoantibodies directed against protein and miRNA components of GW/P bodies have been associated with autoimmune diseases, neurological diseases and cancer. Understanding the molecular function of GW/P bodies and their interactions with other cRNPB may provide clues to the etiology or pathogenesis of diseases associated with autoantibodies directed to these structures. This chapter will focus on the similarities and differences of the various cRNPB as an approach to understanding their functional relationships to GW/P bodies.

An SNP in the trinucleotide repeat region of the TNRC6A gene maps to a major TNGW1 autoepitope in patients with autoantibodies to GW182.

GW/P bodies contain two TNRC6A protein isoforms (GW182 and TNGW1) that function as translational repressors of mRNA through Ago2-mediated RNA silencing. Autoantibodies to GW/P body components GW182, Ge-1 and Ago2 have previously been correlated with clinical autoimmune diseases including neurological disease, Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis and primary biliary cirrhosis. No studies were published to date examining if patients with autoantibodies directed against GW/P bodies contain autoantibodies to the trinucleotide repeat (TNR) region of TNGW1, which differs from GW182 only by the addition of an N-terminal QP-rich 253 amino acid sequence. Our data show that 85.7% of GW/P body positive plasma contain autoantibodies to various epitopes in the TNR region of TNGW1. Given the association of neurological diseases with autoantibodies directed to the TNR region on exon 5 of TNRC6A, this study examined whether there were TNR expansions as described in other neurological diseases and/or mutations in the nucleotide sequence of the CAG/CCA/G-rich region in seven anti-GW/P body positive patients, six control and eight breast cancer patients. Although a TNR expansion was not identified, 28.6% of patients containing autoantibodies to the TNR of TNGW1 were shown to have a single nucleotide polymorphism (SNP) at c.344C > A in the CAG/CCA/G-rich region of TNRC6A, which when translated, would produce a protein variant of p.Pro115Gln. The amino acid change may alter the structure of TNGW1 and/or perturb its miRNA regulatory function although this has not been examined experimentally. A putative change in protein structure may lead to a loss of tolerance to the TNGW1 protein or result in a "neo-antigen" in patients containing the specific TNRC6A SNPs. Further studies of a larger cohort of GW/P body positive patients and structure-function relationships of the variant TNRC6A are required to fully understand the role that such SNPs play in GW/P body autoantibody production and/or pathogenesis of related autoimmune diseases.

Repression of GW/P body components and the RNAi microprocessor impacts primary ciliogenesis in human astrocytes.

BACKGROUND: In most cells, the centriolar component of the centrosome can function as a basal body supporting the formation of a primary cilium, a non-motile sensory organelle that monitors information from the extracellular matrix and relays stimuli into the cell via associated signaling pathways. Defects in the formation and function of primary cilia underlie multiple human diseases and are hallmarks of malignancy. The RNA silencing pathway is involved in the post-transcriptional silencing of > 50% of mRNA that occurs within GW/P bodies. GW/P bodies are found throughout the cytoplasm and previously published live cell imaging data suggested that in a malignant cell type (U2OS), two GW/P bodies reside at the centrosome during interphase. This led us to investigate if a similar relationship exists in primary cells and if the inhibition of the miRNA pathway impairs primary cilium formation. RESULTS: Two GW/P bodies as marked by GW182 and hAgo2 colocalized to the basal body of primary human astrocytes as well as human synoviocytes during interphase and specifically with the distal end of the basal body in the pericentriolar region. Since it is technically challenging to examine the two centrosomal GW/P bodies in isolation, we investigated the potential relationship between the global population of GW/P bodies and primary ciliogenesis. Astrocytes were transfected with siRNA directed to GW182 and hAgo2 and unlike control astrocytes, a primary cilium was no longer associated with the centrosome as detected in indirect immunofluorescence assays. Ultrastructural analysis of siRNA transfected astrocytes revealed that knock down of GW182, hAgo2, Drosha and DGCR8 mRNA did not affect the appearance of the earliest stage of ciliogenesis but did prevent the formation and elongation of the ciliary axoneme. CONCLUSIONS: This study confirms and extends a previously published report that GW/P bodies reside at the centrosome in U2OS cells and documents that GW/P bodies are resident at the centrosome in diverse non-malignant cells. Further, our study demonstrates that repression of key effector proteins in the post-transcriptional miRNA pathway impairs primary cilium formation.