Nucleic acid-induced dimerization of HIV-1 Gag protein.

HIV-1 Gag is a highly flexible multidomain protein that forms the protein lattice of the immature HIV-1 virion. In vitro, it reversibly dimerizes, but in the presence of nucleic acids (NAs), it spontaneously assembles into virus-like particles (VLPs). High-resolution structures have revealed intricate details of the interactions of the capsid (CA) domain of Gag and the flanking spacer peptide SP1 that stabilize VLPs, but much less is known about the assembly pathway and the interactions of the highly flexible NA-binding nucleocapsid (NC) domain. Here, using a novel hybrid fluorescence proximity/sedimentation velocity method in combination with calorimetric analyses, we studied initial binding events by monitoring the sizes and conformations of complexes of Gag with very short oligonucleotides. We observed that high-affinity binding of oligonucleotides induces conformational changes in Gag accompanied by the formation of complexes with a 2:1 Gag/NA stoichiometry. This NA-liganded dimerization mode is distinct from the widely studied dimer interface in the CA domain and from protein interactions arising in the SP1 region and may be mediated by protein-protein interactions localized in the NC domain. The formation of the liganded dimer is strongly enthalpically driven, resulting in higher dimerization affinity than the CA-domain dimer. Both detailed energetic and conformational analyses of different Gag constructs revealed modulatory contributions to NA-induced dimerization from both matrix and CA domains. We hypothesize that allosterically controlled self-association represents the first step of VLP assembly and, in concert with scaffolding along the NA, can seed the formation of two-dimensional arrays near the NA.

Accuracy of Resident-Performed Point-of-Care Lung Ultrasound Examinations Versus Chest Radiography in Pneumothorax Follow-up After Tube Thoracostomy in Rwanda.

OBJECTIVES: The aim of this study was to evaluate the accuracy and timeliness of resident-performed point-of-care lung ultrasound (LUS) examinations for the follow-up of pneumothorax (PTX) after tube thoracostomy. METHODS: After brief training, Rwandan surgical residents blinded to chest radiography (CXR) performed and interpreted LUS examinations for PTX in participants undergoing CXR for PTX follow-up. Treating clinicians interpreted CXR for the presence of PTX for therapeutic decisions. Lung ultrasound was later reviewed by ultrasound experts, and CXR was reviewed by a radiologist. We defined expert LUS interpretation as the reference standard. The sensitivity and specificity of resident-performed LUS examinations for diagnosing PTX were calculated. We assessed agreement between trained resident versus expert LUS and clinician versus radiology CXR using the Cohen κ coefficient. We compared the time to results between LUS and CXR. RESULTS: Over an 8-month period, 51 participants were enrolled. Compared to expert LUS interpretation, the sensitivity and specificity (95% confidence intervals) of resident LUS were 100% (85%-100%) and 96% (82%-100%), respectively, whereas the sensitivity and specificity of clinician-interpreted CXR were 48% (27%-69%) and 100% (88%-100%). The agreement between resident and expert LUS was excellent (κ = 0.96), whereas the agreement between clinician and radiologist CXR was only moderate (κ = 0.60). The time to results was significantly longer for CXR than LUS (mean, 1335 versus 396 minutes; P = .0001). CONCLUSIONS: A resident-performed LUS examination was a quicker imaging modality with superior sensitivity compared to clinician-interpreted CXR for PTX follow-up after tube thoracostomy in this Rwandan study. Lung ultrasound can be a valuable imaging tool for PTX follow-up, especially in resource-limited settings.

Oncologic Outcome and Morbidity in the Elderly Rectal Cancer Patients After Preoperative Chemoradiotherapy and Total Mesorectal Excision: A Multi-institutional and Case-matched Control Study.

OBJECTIVE: To determine the toxicity and oncologic outcome of neoadjuvant chemoradiotherapy (CRT) followed by curative total mesorectal excision (TME) in the elderly (≥70 yrs) and younger (<70 yrs) rectal cancer patients. BACKGROUND: Sufficient data for elderly rectal cancer patients who received definitive trimodality have not been accumulated yet. PATIENTS AND METHODS: A total of 1232 rectal cancer patients who received neoadjuvant CRT and TME were enrolled in this study. After propensity-score matching, 310 younger patients and 310 elderly patients were matched with 1:1 manner. Treatment response, toxicity, surgical outcome, recurrence, and survival were assessed and compared between the 2 groups of patients. RESULTS: The median age was 58 years for the younger patient group and 74 years for the elderly group. Pathologic complete response rates were not significantly different between the 2 groups (younger and elderly: 17.1% vs 14.8%, P = 0.443). The 5-year recurrence-free survival (younger and elderly: 67.7% vs 65.5%, P = 0.483) and overall survival (younger and elderly: 82.9% vs. 79.5%, P = 0.271) rates were not significantly different between the 2 groups either. Adjuvant chemotherapy after surgery was less frequently delivered to the elderly than that to younger patients (83.9% vs 69.0%). Grade 3 or higher acute hematologic toxicity was observed more frequently in the elderly than that in the younger group (9.0% vs 16.1%, P = 0.008). Late complication rate was higher in the elderly group compared with that in the younger group without statistical significance (2.6% vs 4.5%, P = 0.193). CONCLUSIONS: Although acute hematologic toxicity was observed more frequently in the elderly patients than that in the younger patients, elderly rectal cancer patients with good performance status who received preoperative CRT and TME showed favorable tumor response and recurrence-free survival similar to younger patients.

Effect of gemigliptin on glycaemic variability in patients with type 2 diabetes (STABLE study).

The aim of this study was to evaluate the effect of gemigliptin vs sitagliptin or glimepiride as initial combination therapy with metformin on glycaemic variability and to assess the correlation between glycaemic variability reduction and the dipeptidyl peptidase-4 (DPP-4) inhibition in patients with type 2 diabetes. This multicentre, randomized, active-controlled, open-label exploratory study included 69 patients with HbA1c > 7.5%. Subjects were randomized to receive gemigliptin 50 mg (n = 24), sitagliptin 100 mg (n = 23) or glimepiride 2 mg (n = 22) for 12 weeks. After 12 weeks, the change in mean amplitude of glycaemic excursion (MAGE) compared with baseline was significantly lower in the DPP-4 inhibitor groups compared with that in patients who received glimepiride. Furthermore, the standard deviation (SD) of glucose was significantly lower in patients who received gemigliptin than that in patients who received sitagliptin or glimepiride. The DPP-4 inhibition was significantly correlated with changes in MAGE and SD of glucose. In conclusion, gemigliptin and sitagliptin were more effective than glimepiride in reducing glycaemic variability as initial combination therapy with metformin in patients with type 2 diabetes, and the DPP-4 inhibition was associated with a reduction in glycaemic variability.

Comparison of diagnostic accuracy of plain film radiographs between original film and smartphone capture: a pilot study.

The use of mobile devices for medical image capture has become increasingly popular given the widespread use of smartphone cameras. Prior studies have generally compared mobile phone capture images to digitized images. However, many underserved and rural areas without picture archiving and communication systems (PACS) still depend greatly on the use of film radiographs. Additionally, there is a scarcity of specialty-trained or formally licensed radiologists in many of these regions. Subsequently, there is great potential for the use of smartphone capture of plain radiograph films which would allow for increased access to economical and efficient consultation from board-certified radiologists abroad. The present study addresses the ability to diagnose a subset of radiographic findings identified on both the original film radiograph and the captured camera phone image.

Association between Multiple Myeloma and Ulcerative Colitis: A Cross-Sectional Analysis.

BACKGROUND AND AIMS: Multiple myeloma (MM) is a plasma cell dyscrasia that is common among patients with autoimmune diseases. However, the association between ulcerative colitis (UC) and multiple myeloma (MM) is yet to be established. We aimed to evaluate the prevalence of MM among patients with UC in the United States. METHODS: This cross-sectional cohort analysis used the National Inpatient Sample from 2015-2018 to assess the overall MM prevalence among patients with and without UC, and within specific demographic subgroups. Prevalences were compared using a logistic regression model controlling for sex and age. RESULTS: The crude prevalence of MM among patients with UC (n = 1750) compared with patients without UC (n = 366,265) was 0.44% vs. 0.37%, respectively. Patients with UC had increased overall odds of having MM (odds ratio (OR), 1.26). Males with UC had higher prevalence of MM (53.7% vs. 46.3%, respectively) than females. Patients with UC and MM were more likely to be African American than White (15.6% vs. 9.2%, respectively). Patients with UC age >64 had a higher prevalence of MM than those aged below 65 (70.9% vs. 29.1%, respectively). Patients with UC who were obese (BMI > 30) had a higher prevalence of MM than those who were non-obese (12.6% vs. 8.3%). CONCLUSIONS: Overall, UC appears to be associated with MM. This association can be particularly observed in specific demographic groups, such as obese, African American males, or patients >64 years of age. Thus, a high degree of clinical suspicion for MM is warranted, even with minimal symptomatology, in patients with UC, in particular among elder, obese, and African American males.

A Rare Case of Refractory Catastrophic Antiphospholipid Syndrome Successfully Treated With Rituximab and Plasma Exchange.

A small subset of patients with antiphospholipid syndrome (APS) may develop widespread thrombotic disease with organ damage, referred to as catastrophic APS (CAPS) that is associated with a high mortality. Medical therapy typically involves a combination of anticoagulation, systemic glucocorticoids, plasmapheresis, and intravenous immune globulin (IVIG). There is currently no consensus for the management of refractory cases of CAPS. However, monoclonal antibodies such as rituximab and eculizumab have shown some benefits. Herein, we present a 29-year-old female with previous pulmonary embolism who presented with necrotic left toes and was eventually diagnosed with refractory CAPS, successfully treated with Plasmapheresis and Rituximab. With this case report, we hope to encourage the usage of Rituximab in the management of CAPS.

Primary Cardiac Sarcoma: Clinical Characteristics and Prognostic Factors over the Past 2 Decades.

BACKGROUND: Primary cardiac sarcomas (PCS) are extremely rare malignant tumors involving the heart. Only isolated case reports have been described in the literature over different periods of time. This pathology has been associated with a dismal prognosis and given its rarity; treatment options are very limited. Furthermore, there are contrasting data about the effectiveness of current treatment modalities in improving the survival of patients with PCS, including surgical resection which is the mainstay of therapy. There is a paucity of data on the epidemiological characteristics of PCS. This study has the objective of investigating the epidemiologic characteristics, survival outcomes, and independent prognostic factors of PCS. METHODS: A total of 362 patients were ultimately registered in our study from the Surveillance, Epidemiology, and End Results (SEER) database. The study period was from 2000 to 2017. Demographics such as clinical characteristics, overall mortality (OM), and PCS-specific mortality (CSM) were taken into account. A p value of <0.1 in the univariate analysis leads to the incorporation of the variable into multivariate analysis adjusting for covariates. Adverse prognostic factors were represented by a Hazard Ratio (HR) greater than one. The five-year survival analysis was carried out using the Kaplan-Meier method and the log-rank test was used to compare survival curves. RESULTS: Crude analysis revealed a high OM in age 80+ (HR = 5.958, 95% CI 3.357-10.575, p < 0.001), followed by age 60-79 (HR = 1.429, 95% CI 1.028-1.986, p = 0.033); and PCS with distant metastases (HR = 1.888, 95% CI 1.389-2.566, p < 0.001). Patients that underwent surgical resection of the primary tumor and patients with malignant fibrous histiocytomas (HR = 0.657, 95% CI 0.455-0.95, p = 0.025) had a better OM (HR = 0.606, 95% CI 0.465-0.791, p < 0.001). The highest cancer-specific mortality was observed in age 80+ (HR = 5.037, 95% CI 2.606-9.736, p < 0.001) and patients with distant metastases (HR = 1.953, 95% CI 1.396-2.733, p < 0.001). Patients with malignant fibrous histiocytomas (HR = 0.572, 95% CI 0.378-0.865, p = 0.008) and those who underwent surgery (HR = 0.581, 95% CI 0.436-0.774, p < 0.001) had a lower CSM. Patients in the age range 80+ (HR = 13.261, 95% CI 5.839-30.119, p < 0.001) and advanced disease with distant metastases (HR = 2.013, 95% CI 1.355-2.99, p = 0.001) were found to have a higher OM in the multivariate analyses adjusting for covariates). Lower OM was found in patients with rhabdomyosarcoma (HR = 0.364, 95% CI 0.154-0.86, p = 0.021) and widowed patients (HR = 0.506, 95% CI 0.263-0.977, p = 0.042). Multivariate cox proportional hazard regression analyses of CSM also revealed higher mortality of the same groups, and lower mortality in patients with Rhabdomyosarcoma. CONCLUSION: In this United States population-based retrospective cohort study using the SEER database, we found that cardiac rhabdomyosarcoma was associated with the lowest CSM and OM. Furthermore, as expected, age and advanced disease at diagnosis were independent factors predicting poor prognosis. Surgical resection of the primary tumor showed lower CSM and OM in the crude analysis but when adjusted for covariates in the multivariate analysis, it did not significantly impact the overall mortality or the cancer-specific mortality. These findings allow for treating clinicians to recognize patients that should be referred to palliative/hospice care at the time of diagnosis and avoid any surgical interventions as they did not show any differences in mortality. Surgical resection, adjuvant chemotherapy, and/or radiation in patients with poor prognoses should be reserved as palliative measures rather than an attempt to cure the disease.

A claudin-9-based ion permeability barrier is essential for hearing.

Hereditary hearing loss is one of the most common birth defects, yet the majority of genes required for audition is thought to remain unidentified. Ethylnitrosourea (ENU)-mutagenesis has been a valuable approach for generating new animal models of deafness and discovering previously unrecognized gene functions. Here we report on the characterization of a new ENU-induced mouse mutant (nmf329) that exhibits recessively inherited deafness. We found a widespread loss of sensory hair cells in the hearing organs of nmf329 mice after the second week of life. Positional cloning revealed that the nmf329 strain carries a missense mutation in the claudin-9 gene, which encodes a tight junction protein with unknown biological function. In an epithelial cell line, heterologous expression of wild-type claudin-9 reduced the paracellular permeability to Na+ and K+, and the nmf329 mutation eliminated this ion barrier function without affecting the plasma membrane localization of claudin-9. In the nmf329 mouse line, the perilymphatic K+ concentration was found to be elevated, suggesting that the cochlear tight junctions were dysfunctional. Furthermore, the hair-cell loss in the claudin-9-defective cochlea was rescued in vitro when the explanted hearing organs were cultured in a low-K+ milieu and in vivo when the endocochlear K+-driving force was diminished by deletion of the pou3f4 gene. Overall, our data indicate that claudin-9 is required for the preservation of sensory cells in the hearing organ because claudin-9-defective tight junctions fail to shield the basolateral side of hair cells from the K+-rich endolymph. In the tight-junction complexes of hair cells, claudin-9 is localized specifically to a subdomain that is underneath more apical tight-junction strands formed by other claudins. Thus, the analysis of claudin-9 mutant mice suggests that even the deeper (subapical) tight-junction strands have biologically important ion barrier function.

15-Deoxy-Delta-12,14-prostaglandin J2 modulates pro-labour and pro-inflammatory responses in human myocytes, vaginal and amnion epithelial cells.

Background: Prematurity is the leading cause of childhood death under the age of five. The aetiology of preterm birth is multifactorial; however, inflammation and infection are the most common causal factors, supporting a potential role for immunomodulation as a therapeutic strategy. 15-Deoxy-Delta-12,14-prostaglandin J2 (15dPGJ2) is an anti-inflammatory prostaglandin and has been shown to delay lipopolysaccharide (LPS) induced preterm labour in mice and improve pup survival. This study explores the immunomodulatory effect of 15dPGJ2 on the transcription factors NF-κB and AP-1, pro-inflammatory cytokines, and contraction associated proteins in human cultured myocytes, vaginal epithelial cell line (VECs) and primary amnion epithelial cells (AECs). Methods: Cells were pre-incubated with 32µM of 15dPGJ2 and stimulated with 1ng/mL of IL-1ß as an in vitro model of inflammation. Western immunoblotting was used to detect phosphorylated p-65 and phosphorylated c-Jun as markers of NF-κB and AP-1 activation, respectively. mRNA expression of the pro-inflammatory cytokines IL-6, IL-8, and TNF-α was examined, and protein expression of COX-2 and PGE2 were detected by western immunoblotting and ELISA respectively. Myometrial contractility was examined ex-vivo using a myograph. Results: 15dPGJ2 inhibited IL-1ß-induced activation of NF-κB and AP-1, and expression of IL-6, IL-8, TNF-α, COX-2 and PGE2 in myocytes, with no effect on myometrial contractility or cell viability. Despite inhibiting IL-1ß-induced activation of NF-κB, expression of IL-6, TNF-α, and COX-2, 15dPGJ2 led to activation of AP-1, increased production of PGE2 and increased cell death in VECs and AECs. Conclusion: We conclude that 15dPGJ2 has differential effects on inflammatory modulation depending on cell type and is therefore unlikely to be a useful therapeutic agent for the prevention of preterm birth.

Safety and metabolic advantages of steroid withdrawal after 6 months posttransplant in de novo kidney transplantation: A 1-year prospective cohort study.

INTRODUCTION: This prospective multicenter study aimed at investigating the safety and metabolic advantages of steroid withdrawal (SW) therapy in kidney transplant recipients with tacrolimus-mycophenolate mofetil-based immunosuppression. METHODS: We analyzed 179 recipients who received kidney transplantation from March 2016 and September 2018. In 179 recipients, 114 patients maintained an immunosuppressive regimen including steroids (steroid continuation [SC] group). The remaining 65 patients were determined to withdraw steroid therapy after 6 months posttransplant (SW group). Metabolic parameters and graft functions of the two groups were evaluated. RESULTS: The estimated glomerular filtration rates at 12 months posttransplant were 67.29 ± 20.29 ml/min/1.73 m2 in SC group and 73.72 ± 17.57 ml/min/1.73 m2 in SW group (p < .001). The acute rejection occurred to four recipients in the SC group (3.5%) and no acute rejection occurred to SW group recipients during the 6-2 months posttransplant period. Oral glucose tolerance tests revealed that recipients in the SW group were more improved in glucose metabolism than the SC group during 6-12 months posttransplant. In addition, cholesterol levels and blood pressure decreased after the withdrawal of steroids in the SW group. CONCLUSION: In conclusion, a 6-month withdrawal of steroids in recipients with low immunological risk and stable graft function can be safely conducted and result in improvement of metabolic profiles. Stable recipients without biopsy-proven acute rejection and proteinuria can safely withdraw from steroids out of a maintenance immunosuppressive regimen 6-months posttransplant. A long-term follow-up study is needed to verify our results.

Solid-State Synthesis of Silver Nanoparticles at Room Temperature: Poly(vinylpyrrolidone) as a Tool.

Silver nanoparticles have been used for a long time and recently various methods have been additionally developed for their production. Here we report for the first time a solid-state high-speed vibration milling method for the synthesis of silver nanoparticles, in which poly(vinylpyrrolidone) is used for the reduction of the silver salt. The synthesis is performed at room temperature and no surfactant to direct the anisotropic growth of the nanoparticles is required. The formation of the nanoparticles was studied by UV-Visible spectroscopy, transmission electron microscopy, and powder X-ray diffraction techniques. The nanoparticles synthesized were found to be uniform in size and shape with an average diameter of less than 5 nm. In addition, the antimicrobial activity of these silver nanoparticles was investigated against Escherichia coli and found to be positive.

Differential Response of Gestational Tissues to TLR3 Viral Priming Prior to Exposure to Bacterial TLR2 and TLR2/6 Agonists.

Background: Infection/inflammation is an important causal factor in spontaneous preterm birth (sPTB). Most mechanistic studies have concentrated on the role of bacteria, with limited focus on the role of viruses in sPTB. Murine studies support a potential multi-pathogen aetiology in which a double or sequential hit of both viral and bacterial pathogens leads to a higher risk preterm labour. This study aimed to determine the effect of viral priming on bacterial induced inflammation in human in vitro models of ascending and haematogenous infection. Methods: Vaginal epithelial cells, and primary amnion epithelial cells and myocytes were used to represent cell targets of ascending infection while interactions between peripheral blood mononuclear cells (PBMCs) and placental explants were used to model systemic infection. To model the effect of viral priming upon the subsequent response to bacterial stimuli, each cell type was stimulated first with a TLR3 viral agonist, and then with either a TLR2 or TLR2/6 agonist, and responses compared to those of each agonist alone. Immunoblotting was used to detect cellular NF-κB, AP-1, and IRF-3 activation. Cellular TLR3, TLR2, and TLR6 mRNA was quantified by RT-qPCR. Immunoassays were used to measure supernatant cytokine, chemokine and PGE2 concentrations. Results: TLR3 ("viral") priming prior to TLR2/6 agonist ("bacterial") exposure augmented the pro-inflammatory, pro-labour response in VECs, AECs, myocytes and PBMCs when compared to the effects of agonists alone. In contrast, enhanced anti-inflammatory cytokine production (IL-10) was observed in placental explants. Culturing placental explants in conditioned media derived from PBMCs primed with a TLR3 agonist enhanced TLR2/6 agonist stimulated production of IL-6 and IL-8, suggesting a differential response by the placenta to systemic inflammation compared to direct infection as a result of haematogenous spread. TLR3 agonism generally caused increased mRNA expression of TLR3 and TLR2 but not TLR6. Conclusion: This study provides human in vitro evidence that viral infection may increase the susceptibility of women to bacterial-induced sPTB. Improved understanding of interactions between viral and bacterial components of the maternal microbiome and host immune response may offer new therapeutic options, such as antivirals for the prevention of PTB.

The roles of membrane estrogen receptor subtypes in modulating dopamine transporters in PC-12 cells.

The effects of 17beta-estradiol (E(2)) on dopamine (DA) transport could explain gender and life-stage differences in the incidence of some neurological disorders. We tested the effects of E(2) at physiological concentrations on DA efflux in nerve growth factor-differentiated rat pheochromocytoma cells that express estrogen receptors (ER) alpha, ERbeta, and G-protein coupled receptor 30 (GPR30), and DA transporter (DAT). DAT efflux was determined as the transporter-specific loss of (3)H-DA from pre-loaded cells; a 9-15 min 10(-9 )M E(2) treatment caused maximal DA efflux. Such rapid estrogenic action suggests a non-genomic response, and an E(2)-dendrimer conjugate (limited to non-nuclear actions) caused DA efflux within 5 min. Efflux dose-responses for E(2) were non-monotonic, also characteristic of non-genomic estrogenic actions. ERalpha siRNA knockdown abolished E(2)-mediated DA efflux, while ERbeta knockdown did not, and GPR30 knockdown increased E(2)-mediated DA efflux (suggesting GPR30 is inhibitory). Use of ER-selective agonists/antagonists demonstrated that ERalpha is the predominant mediator of E(2)-mediated DA efflux, with inhibitory contributions from GPR30 and ERbeta. E(2) also caused trafficking of ERalpha to the plasma membrane, trafficking of ERbeta away from the plasma membrane, and unchanged membrane GPR30 levels. Therefore, ERalpha is largely responsible for non-genomic estrogenic effects on DAT activity.

Tarantula toxins interact with voltage sensors within lipid membranes.

Voltage-activated ion channels are essential for electrical signaling, yet the mechanism of voltage sensing remains under intense investigation. The voltage-sensor paddle is a crucial structural motif in voltage-activated potassium (K(v)) channels that has been proposed to move at the protein-lipid interface in response to changes in membrane voltage. Here we explore whether tarantula toxins like hanatoxin and SGTx1 inhibit K(v) channels by interacting with paddle motifs within the membrane. We find that these toxins can partition into membranes under physiologically relevant conditions, but that the toxin-membrane interaction is not sufficient to inhibit K(v) channels. From mutagenesis studies we identify regions of the toxin involved in binding to the paddle motif, and those important for interacting with membranes. Modification of membranes with sphingomyelinase D dramatically alters the stability of the toxin-channel complex, suggesting that tarantula toxins interact with paddle motifs within the membrane and that they are sensitive detectors of lipid-channel interactions.

TIRF-Based Single-Molecule Detection of the RecA Presynaptic Filament Dynamics.

RecA is a key protein in homologous DNA repair process. On a single-stranded (ss) DNA, which appears as an intermediate structure at a double-strand break site, RecA forms a kilobase-long presynaptic filament that mediates homology search and strand exchange reaction. RecA requires adenosine triphosphate as a cofactor that confers dynamic features to the filament such as nucleation, end-dependent growth and disassembly, scaffold shift along the ssDNA, and conformational change. Due to the complexity of the dynamics, detailed molecular mechanisms of functioning presynaptic filament have been characterized only recently after the advent of single-molecule techniques that allowed real-time observation of each kinetic process. In this chapter, single-molecule fluorescence resonance energy transfer assays, which revealed detailed molecular pictures of the presynaptic filament dynamics, will be discussed.

Mitochondrial respiratory complex I deficiency simulating spinal muscular atrophy.

Two female patients with clinical features resembling spinal muscular atrophy were presented. Patient 1 presented with hypotonia and proximal weakness of extremities at age 4 months. Electromyography revealed motor neuronopathy suggestive of spinal muscular atrophy. Patient 2 presented with severe hypotonia, motor weakness, and joint contractures since birth. Muscle biopsy findings were consistent with spinal muscular atrophy. However, deletions in the survival motor neuron gene and the neuronal apoptosis inhibitor protein gene were not found in both patients. They finally manifested clinical features unlike spinal muscular atrophy: epileptic seizure, cardiomyopathy, and spasticity. The clinical course of each patient was not like that of spinal muscular atrophy type I. Mitochondrial respiratory chain complex enzyme activities in cultured skin fibroblasts were measured. Respiratory complex I enzyme activity was decreased, suggestive of isolated complex I deficiency in both patients. In conclusion, in patients who have clinical features resembling spinal muscular atrophy but no deletions in the spinal muscular atrophy gene, the possibility of the mitochondrial respiratory chain complex I deficiency should be considered.

Contemporary Outcomes of Surgical Repair of Total Anomalous Pulmonary Venous Connection in Patients With Heterotaxy Syndrome.

BACKGROUND: Total anomalous pulmonary venous connection (TAPVC) is prevalent in patients with atriovisceral heterotaxy. Although functionally univentricular heart defects are common in heterotaxy syndromes, the extent to which this association influences overall risk for TAPVC repair is undefined. This study examines multiinstitutional experience with TAPVC repair in infants with heterotaxy using a national clinical registry. METHODS: The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) (2002-2012) was queried for patients with heterotaxy syndrome who underwent TAPVC repair, with or without concomitant procedures at age of 90 days or younger. The cohort was divided into single ventricle (SV) and non-single ventricle (non-SV) groups based on STS-CHSD codes. Patient characteristics and in-hospital outcomes were described. RESULTS: Sixty-five centers reported 261 TAPVC repair operations (females, 115 [44%]; median [interquartile range] age and weight, 7 days [3-19 days] and 3.1 kg [2.7-3.5 kg]). Overall, 180 (69%) patients were identified with asplenia or right atrial isomerism, and 167 (64%) had SV diagnoses. Discharge mortality was 38%. Postoperatively, the median length of stay was 18 days (7-32 days), 20 (8%) patients required extracorporeal membrane oxygenation support, and 11 (4%) had reoperation for pulmonary vein stenosis. Mortality was higher for patients with SV defects (SV, 43% versus non-SV, 30%; p = 0.03). Length of stay, postoperative extracorporeal membrane oxygenation, and reoperation for pulmonary vein stenosis was similar between SV and non-SV groups. Overall, there was no difference in mortality for patients undergoing concomitant systemic-to-pulmonary artery shunt (p = 0.134) or surgery within 48 hours of birth (p = 0.876). CONCLUSIONS: Total anomalous pulmonary venous connection repair in heterotaxy patients carries a high mortality risk, particularly with functionally univentricular physiology. These multiinstitutional data serve as an important benchmark and may be useful for risk stratification and counseling.

Gene regulation by glucocorticoid in ENaC-mediated Na⁺ transport by middle ear epithelial cells.

OBJECTIVES/HYPOTHESIS: The epithelial sodium channel (ENaC) is a Na(+) transport channel located in the apical membrane of the human middle ear epithelium. Although ENaC-mediated sodium transport has been reported to be upregulated by dexamethasone in human middle ear epithelium, there has been no study of the downstream pathways for increased ENaC expression mediated by glucocorticoids in this tissue. We investigated the effect of dexamethasone on the expression of ENaC and glucocorticoid regulatory genes for ENaC expression in human middle ear epithelial cells (HMEECs). STUDY DESIGN: In vitro investigation. METHODS: Real-time RT-PCR and Western blot analysis were used to determine the expression level of ENaC and its regulatory genes in HMEECs. RESULTS: The transcript and protein expression of the α-, ß-, and γ-ENaC subunits were all upregulated by dexamethasone (100 nM) in HMEECs. Dexamethasone treatment also increased the transcript expression of serum/glucocorticoid-regulated kinase1 (SGK1) and neural precursor cell-expressed developmentally downregulated (Nedd) 4-2, and decreased the transcript expression of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1). ENaC transcript expression was not changed after mifepristone (a glucocorticoid antagonist, 100 nM) + dexamethasone treatment when compared to the control, but increased after spironolactone (a mineralocorticoid antagonist, 100 nM) + dexamethasone treatment. CONCLUSIONS: These findings indicate that dexamethasone increases the transcript and protein expression of the α-, ß-, and γ-ENaC subunits via the GR-SGK1-Nedd4-2 pathway and provides insight into the molecular mechanism of the increased sodium transport mediated by ENaC with steroid treatment in HMEECs. LEVEL OF EVIDENCE: N/A.

Periodic alternating nystagmus of peripheral vestibular origin.

OBJECTIVES/HYPOTHESIS: Periodic alternating nystagmus (PAN) is most commonly found either in its congenital form or after cerebellar/pontomedullary lesions. However, we identified PAN in 10 patients with peripheral vestibular disorders and will try to describe their characteristics to aid in the differential diagnosis between peripheral and central etiologies. STUDY DESIGN: Observation of a case series. METHOD: Peripheral vestibular lesions were confirmed by neurological examinations, vestibular function tests, and brain magnetic resonance imaging (MRIs). Eye movements of the patients were recorded using electronystagmography or video nystagmography for a minimum of 10 minutes to confirm the nystagmus change in direction. RESULTS: The final diagnoses of the patients included Meniere's disease (n = 3), acute labyrinthitis (n = 4), sudden sensorineural hearing loss with vertigo (n = 2), and vestibular schwannoma (n = 1). Direction-changing spontaneous horizontal nystagmus with quiescent intervals was observed in all patients under dark conditions. The nystagmus was suppressed by visual fixation; and the results of oculomotor tests were normal for saccadic and smooth pursuit eye movements and optokinetic nystagmus. All patients showed mild to complete canal paresis on a bithermal caloric test. PAN progressed into unidirectional nystagmus of the contra-lesion side in all patients within 48 hours. CONCLUSION: PAN can be observed in patients with peripheral vestibular disorders, but detecting PAN in this subpopulation is difficult because of its transitory nature. The absence of central symptoms and signs, the visual suppression of PAN, normal oculomotor tests, and transient persistence are important diagnostic clues for differentiating peripheral from central PAN. LEVEL OF EVIDENCE: 4.