Induction of the alternative lengthening of telomeres pathway by trapping of proteins on DNA.

Telomere maintenance is a hallmark of malignant cells and allows cancers to divide indefinitely. In some cancers, this is achieved through the alternative lengthening of telomeres (ALT) pathway. Whilst loss of ATRX is a near universal feature of ALT-cancers, it is insufficient in isolation. As such, other cellular events must be necessary - but the exact nature of the secondary events has remained elusive. Here, we report that trapping of proteins (such as TOP1, TOP2A and PARP1) on DNA leads to ALT induction in cells lacking ATRX. We demonstrate that protein-trapping chemotherapeutic agents, such as etoposide, camptothecin and talazoparib, induce ALT markers specifically in ATRX-null cells. Further, we show that treatment with G4-stabilising drugs cause an increase in trapped TOP2A levels which leads to ALT induction in ATRX-null cells. This process is MUS81-endonuclease and break-induced replication dependent, suggesting that protein trapping leads to replication fork stalling, with these forks being aberrantly processed in the absence of ATRX. Finally, we show ALT-positive cells harbour a higher load of genome-wide trapped proteins, such as TOP1, and knockdown of TOP1 reduced ALT activity. Taken together, these findings suggest that protein trapping is a fundamental driving force behind ALT-biology in ATRX-deficient malignancies.

A key feature of all cancer cells is their ability to divide indefinitely, and this is dependent on circumvention of telomere shortening through induction of a telomere maintenance mechanism, such as the telomerase-independent, Alternative Lengthening of Telomeres (ALT) pathway. The ALT pathway is characterised by loss of the ATRX chromatin remodeler. The current study provides evidence that, in the absence of ATRX, increased trapping of proteins on DNA leads to replication fork stalling and collapse. At telomeres, this leads to ALT pathway activity. These results help to better understand ALT tumours and might, eventually, be instrumental in developing new therapeutic strategies.

Examining capillary ketone testing in hospitalised patients: indications and outcomes.

Elevated blood ketone levels (ketosis) in inpatients with diabetes can herald diabetic ketoacidosis (DKA). However, ketosis can also occur in individuals without diabetes in certain settings. It is unclear what proportion of inpatients with ketosis are in DKA and which patients are at the highest risk of DKA. This study determined that many ketone tests are performed in individuals at low risk of DKA, and a ß-hydroxybutyrate <1.0 mmol/L had a low incidence of DKA and less need for escalation in their management.

Challenges in diagnosis of calcaneal fractures: an examination using the WIDI SIM platform.

INTRODUCTION: The calcaneus is the most commonly fractured tarsal bone. Diagnosis is often challenging due to subtle radiographic changes and requires timely identification to prevent complications, including subtalar arthritis, neurovascular injury, malunion, osteomyelitis, and compartment syndrome. Treatment varies based on fracture type, with non-surgical methods for non-displaced stress fractures and surgical interventions for displaced or intra-articular fractures. METHODS: This study utilized the Wisdom in Diagnostic Imaging Simulation (WIDI SIM) platform, an emergency imaging simulation designed to assess radiology resident preparedness for independent call. During an 8-hour simulation, residents were tested on 65 cases across various imaging modalities of varying complexity, including normal studies. A single, unique case of calcaneal fracture was included within the simulation in four separate years of testing. Cases were assessed using a standardized grading rubric by subspecialty radiology faculty, with errors subsequently classified by type. RESULTS: A total of 1279 residents were tested in five separate years on the findings of calcaneal fractures of 5 different patients. Analysis revealed a consistent pattern of missed diagnoses across all training years, primarily attributed to observational errors. There was limited improvement with training progression as all training years exhibited similar average performance levels. CONCLUSIONS: Calcaneal fractures pose a diagnostic challenge due to their frequent subtle radiographic findings, especially in stress fractures. Simulation-based evaluations using WIDI SIM highlighted challenges in radiology residents' proficiency in diagnosing calcaneal fractures. Addressing these challenges through targeted education and exposure to diverse cases is essential to improve diagnostic accuracy and reduce complications with calcaneal fractures.

Thrombolysis Experience in Costa Rica Compared Against Individual Patient Data from two Randomized Controlled Trials.

OBJECTIVES: We sought to compare thrombolysis outcomes from the Costa Rican Stroke Registry Program (CRSRP) with published individual patient data from NINDS and CLOTBUST-ER trials using matching and outcome modeling from randomized clinical trials (RCTs). MATERIALS AND METHODS: A retrospective observational study matching subjects on baseline characteristics, from the CRSRP, the control arm of CLOTBUST-ER, and the interventional arm of NINDS trials. Day 7-10/discharge modified Rankin Score (mRS), and early mortality was compared between matched subjects. A mortality model derived from RCTs was developed, and outcomes were compared at similar baseline NIHSS scores. CRSRP symptomatic hemorrhage (SICH) rate was compared with an Ibero-American cohort (IAC). RESULTS: Of 540 CRSRP patients, 351 received rt-PA under 3 hours and were matched with NINDS subjects yielding 292 pairs; 161 CRSRP subjects treated within 4.5 hours were matched with CLOTBUST-ER subjects resulting in 151 pairs. The proportion of patients achieving excellent outcomes (mRS 0-1) did not differ between CRSRP and either NINDS or CLOTBUST-ER (CRSRP vs NINDS: 36.6% vs 32.9%, p=0.3; CRSRP vs CLOTBUST-ER: 26.5% vs 24.5%, p=0.8). Mortality was higher for CRSRP vs CLOTBUST-ER (7.3% vs 0.7%, p=0.006), but not vs NINDS (6.5% vs 4.5%, p=0.4). A pooled mortality model derived from 15 RCTs representing 4410 patients (R2=0.39) showed CRSRP and NINDS within expected mortality, while CLOTBUST-ER showed lower than expected mortality. CRSRP SICH rate equaled IAC (5.7% vs 5.7%; p=0.9). CONCLUSIONS: Functional outcomes and SICH of thrombolysed Costa Rican patients compared favorably with published datasets, with a potential increase in early mortality.

Naphthoquinones Oxidize H2S to Polysulfides and Thiosulfate, Implications for Therapeutic Applications.

1,4-Napththoquinones (NQs) are clinically relevant therapeutics that affect cell function through production of reactive oxygen species (ROS) and formation of adducts with regulatory protein thiols. Reactive sulfur species (RSS) are chemically and biologically similar to ROS and here we examine RSS production by NQ oxidation of hydrogen sulfide (H2S) using RSS-specific fluorophores, liquid chromatography-mass spectrometry, UV-Vis absorption spectrometry, oxygen-sensitive optodes, thiosulfate-specific nanoparticles, HPLC-monobromobimane derivatization, and ion chromatographic assays. We show that NQs, catalytically oxidize H2S to per- and polysulfides (H2Sn, n = 2−6), thiosulfate, sulfite and sulfate in reactions that consume oxygen and are accelerated by superoxide dismutase (SOD) and inhibited by catalase. The approximate efficacy of NQs (in decreasing order) is, 1,4-NQ ≈ juglone ≈ plumbagin > 2-methoxy-1,4-NQ ≈ menadione >> phylloquinone ≈ anthraquinone ≈ menaquinone ≈ lawsone. We propose that the most probable reactions are an initial two-electron oxidation of H2S to S0 and reduction of NQ to NQH2. S0 may react with H2S or elongate H2Sn in variety of reactions. Reoxidation of NQH2 likely involves a semiquinone radical (NQ·−) intermediate via several mechanisms involving oxygen and comproportionation to produce NQ and superoxide. Dismutation of the latter forms hydrogen peroxide which then further oxidizes RSS to sulfoxides. These findings provide the chemical background for novel sulfur-based approaches to naphthoquinone-directed therapies.

Sonothrombolysis in Patients With Acute Ischemic Stroke With Large Vessel Occlusion: An Individual Patient Data Meta-Analysis.

BACKGROUND AND PURPOSE: Evidence about the utility of ultrasound-enhanced thrombolysis (sonothrombolysis) in patients with acute ischemic stroke (AIS) is conflicting. We aimed to evaluate the safety and efficacy of sonothrombolysis in patients with AIS with large vessel occlusion, by analyzing individual patient data of available randomized-controlled clinical trials. METHODS: We included all available randomized-controlled clinical trials comparing sonothrombolysis with or without addition of microspheres (treatment group) to intravenous thrombolysis alone (control group) in patients with AIS with large vessel occlusion. The primary outcome measure was the rate of complete recanalization at 1 to 36 hours following intravenous thrombolysis initiation. We present crude odds ratios (ORs) and ORs adjusted for the predefined variables of age, sex, baseline stroke severity, systolic blood pressure, and onset-to-treatment time. RESULTS: We included 7 randomized controlled clinical trials that enrolled 1102 patients with AIS. A total of 138 and 134 confirmed large vessel occlusion patients were randomized to treatment and control groups respectively. Patients randomized to sonothrombolysis had increased odds of complete recanalization compared with patients receiving intravenous thrombolysis alone (40.3% versus 22.4%; OR, 2.17 [95% CI, 1.03-4.54]; adjusted OR, 2.33 [95% CI, 1.02-5.34]). The likelihood of symptomatic intracranial hemorrhage was not significantly different between the 2 groups (7.3% versus 3.7%; OR, 2.03 [95% CI, 0.68-6.11]; adjusted OR, 2.55 [95% CI, 0.76-8.52]). No differences in the likelihood of asymptomatic intracranial hemorrhage, 3-month favorable functional and 3-month functional independence were documented. CONCLUSIONS: Sonothrombolysis was associated with a nearly 2-fold increase in the odds of complete recanalization compared with intravenous thrombolysis alone in patients with AIS with large vessel occlusions. Further study of the safety and efficacy of sonothrombolysis is warranted.

Manage Emotions to Reduce Aggression: A Pilot Study of a Brief Treatment to Help Veterans Reduce Impulsive Aggression.

Veterans with posttraumatic stress disorder (PTSD) report more aggression than civilians with PTSD. Because emotion regulation difficulties mediated the relationship between PTSD symptoms and impulsive aggression in veterans, we developed an intervention to increase emotion regulation skills. This pilot study tested the feasibility and acceptability of a three-session treatment, Manage Emotions to Reduce Aggression (MERA), and examined its effectiveness at reducing aggression and emotion dysregulation. Male combat veterans with PTSD and impulsive aggression completed assessments before and 4 weeks after MERA. Overt Aggression Scale measured frequency of aggression; Difficulties in Emotion Regulation Scale assessed emotion dysregulation. Most veterans (95%) who completed MERA and the posttreatment assessment (n = 20) reported MERA was helpful. Veterans in the intent-to-treat sample demonstrated a significant decrease in their frequency of aggression (Cohen's d = -0.55) and emotion dysregulation (Cohen's d = -0.55). MERA may be an innovative treatment that helps veterans reduce aggression.

N-Terminal Charged Residues of Amyloid-ß Peptide Modulate Amyloidogenesis and Interaction with Lipid Membrane.

Interactions of amyloid-ß (Aß) peptides and cellular membranes are proposed to be closely related with Aß neurotoxicity in Alzheimer's disease. In this study, we systematically investigated the effect of the N-terminal hydrophilic region of Aß40 on its amyloidogenesis and interaction with supported phospholipid bilayer. Our results show that modulation of the charge properties of the dynamic N-terminal region dramatically influences the aggregation properties of Aß. Furthermore, our results demonstrate that the N-terminal charged residues play a crucial role in driving the early adsorption and latter remobilization of the peptide on membrane bilayer, and mediating the rigidity and viscoelasticity properties of the bound Aß40 at the membrane interface. The results provide new mechanistic insight into the early Aß-membrane interactions and binding, which may be critical for elucidating membrane-mediated Aß amyloidogenesis in a physiological environment and unravelling the origin of Aß neurotoxicity.

Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters.

Many diseases are associated with oxidative stress, which occurs when the production of reactive oxygen species (ROS) overwhelms the scavenging ability of an organism. Here, we evaluated the carbon nanoparticle antioxidant properties of poly(ethylene glycolated) hydrophilic carbon clusters (PEG-HCCs) by electron paramagnetic resonance (EPR) spectroscopy, oxygen electrode, and spectrophotometric assays. These carbon nanoparticles have 1 equivalent of stable radical and showed superoxide (O2 (•-)) dismutase-like properties yet were inert to nitric oxide (NO(•)) as well as peroxynitrite (ONOO(-)). Thus, PEG-HCCs can act as selective antioxidants that do not require regeneration by enzymes. Our steady-state kinetic assay using KO2 and direct freeze-trap EPR to follow its decay removed the rate-limiting substrate provision, thus enabling determination of the remarkable intrinsic turnover numbers of O2 (•-) to O2 by PEG-HCCs at >20,000 s(-1). The major products of this catalytic turnover are O2 and H2O2, making the PEG-HCCs a biomimetic superoxide dismutase.

Residue-Specific Dynamics and Local Environmental Changes in Aß40 Oligomer and Fibril Formation.

Elucidating local dynamics of protein aggregation is crucial for understanding the mechanistic details of protein amyloidogenesis. Herein, we studied the residue-specific dynamics and local environmental changes of Aß40 along the course of aggregation by using para-cyanophenylalanine (PheCN ) as a fluorescent and vibrational probe. Our results show that the PheCN residues introduced at various positions all exhibited an immediate decay of fluorescence intensity, indicating a relatively synergistic process in early oligomer formation. The fast decreases in the fluorescence intensities of residues 19 and 20 in the central hydrophobic core region and residue 10 in the N-terminal region suggest that they play crucial roles in the formation of the oligomeric core. The PheCN 4 residue exhibits a remarkably slower decrease in fluorescence intensity, implicating its dynamic conformational characteristics in oligomer and fibril formation. Our results also suggest that the N-terminal residues in fibrils are surrounded by a relatively hydrophobic local environment, as opposed to being solvated.

Semiconductor Nanowire Light-Emitting Diodes Grown on Metal: A Direction Toward Large-Scale Fabrication of Nanowire Devices.

Bottom-up nanowires are attractive for realizing semiconductor devices with extreme heterostructures because strain relaxation through the nanowire sidewalls allows the combination of highly lattice mismatched materials without creating dislocations. The resulting nanowires are used to fabricate light-emitting diodes (LEDs), lasers, solar cells, and sensors. However, expensive single crystalline substrates are commonly used as substrates for nanowire heterostructures as well as for epitaxial devices, which limits the manufacturability of nanowire devices. Here, nanowire LEDs directly grown and electrically integrated on metal are demonstrated. Optical and structural measurements reveal high-quality, vertically aligned GaN nanowires on molybdenum and titanium films. Transmission electron microscopy confirms the composition variation in the polarization-graded AlGaN nanowire LEDs. Blue to green electroluminescence is observed from InGaN quantum well active regions, while GaN active regions exhibit ultraviolet emission. These results demonstrate a pathway for large-scale fabrication of solid state lighting and optoelectronics on metal foils or sheets.

The prevalence of epilepsy and association with traumatic brain injury in veterans of the Afghanistan and Iraq wars.

OBJECTIVE: To examine the association of epilepsy with traumatic brain injury (TBI) in Afghanistan and Iraq (Operation Enduring Freedom [OEF]/Operation Iraqi Freedom [OIF]) Veterans. DESIGN: Cross-sectional observational study. PARTICIPANTS: A total 256 284 OEF/OIF Veterans who received inpatient and outpatient care in the Veterans Health Administration in fiscal years 2009-2010. MAIN OUTCOME MEASURES: We used algorithms developed for use with International Classification of Diseases, Ninth Revision, Clinical Modification, codes to identify epilepsy, TBI (penetrating TBI [pTBI]/other TBI), and other risk factors for epilepsy (eg, stroke). TBI and other risk factors were identified prior to the index date (first date of seizure or October 1, 2009) for primary analyses. RESULTS: Epilepsy prevalence was 10.6 per 1000 (N = 2719) in fiscal year 2010; age-adjusted prevalence was 6.1. Of 37 718 individuals with a diagnosis of TBI, 29 297 Veterans had a diagnosis of TBI prior to the index date. Statistically significant associations were found between epilepsy and prior TBI diagnosis (pTBI: adjusted odds ratio = 18.77 [95% confidence interval, 9.21-38.23]; other TBI: adjusted odds ratio = 1.64 [1.43-1.89]). CONCLUSIONS: Among OEF/OIF Veterans, epilepsy was associated with previous TBI diagnosis, with pTBI having the strongest association. Because war-related epilepsy in Vietnam War Veterans with TBI continued 35 years postwar, a detailed, prospective study is needed to understand the relationship between epilepsy and TBI severity in OEF/OIF Veterans.

Emotion dysregulation mediates the relationship between traumatic exposure and aggression in healthy young women.

Research has linked trauma-sequelae, such as posttraumatic stress disorder, to aggression. However, not all who experience a trauma become violent, suggesting non-trauma factors, such as emotion dysregulation, influence aggression expression and if confirmed, may influence treatment approaches. Aggression can be considered a multifaceted construct with Impulsive Aggression (IA) as emotional, reactive, and uncontrolled and Premeditated Aggression (PA) as deliberate, planned, and instrumental. We hypothesized that parceling apart IA and PA may further refine predictors of aggression in the context of trauma exposure. We tested this hypothesis in undergraduate women (N = 208) who completed trauma, emotion, and aggression measures. Path analysis indicated that Borderline Features, including emotion dysregulation, mediated the relationship between trauma exposure and IA and PA. The finding extends clinical literature by providing evidence that emotion dysregulation influences both IA and PA in a non-clinical sample, while clinical sample research shows emotion dysregulation more specifically mediated the relationship between trauma and IA. Factors responsible for these differences are discussed.

Pilot study of intravenous glyburide in patients with a large ischemic stroke.

BACKGROUND AND PURPOSE: Preclinical and retrospective clinical data indicate that glyburide, a selective inhibitor of sulfonylurea receptor 1-transient receptor potential melastatin 4, is effective in preventing edema and improving outcome after focal ischemia. We assessed the feasibility of recruiting and treating patients with severe stroke while obtaining preliminary information on the safety and tolerability of RP-1127 (glyburide for injection). METHODS: We studied 10 patients with acute ischemic stroke, with baseline diffusion-weighted imaging lesion volumes of 82 to 210 cm3, whether treated with intravenous recombinant tissue-type plasminogen activator, age 18 to 80 years, and time to RP-1127≤10 hours. RESULTS: Recruitment was completed within 10 months. The mean age was 50.5 years, and baseline diffusion-weighted image lesion volume was 102±23 cm3. There were no serious adverse events related to drug and no symptomatic hypoglycemia. The increase in ipsilateral hemisphere volume was 50±33 cm3. The proportion of 90-day modified Rankin Scale≤4 was 90% (40% modified Rankin Scale, ≤3). CONCLUSIONS: RP-1127 at a dose of 3 mg/d was well tolerated and did not require any dose reductions. A clinical trial of RP-1127 is feasible. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01268683.

Deep ultraviolet emitting polarization induced nanowire light emitting diodes with AlxGa1-xN active regions.

In this report, we demonstrate band gap tuning of the active region emission wavelength from 365 nm to 250 nm in light emitting diodes fashioned from catalyst-free III-nitride nanowires. Optical characteristics of the nanowire heterostructures and fabricated devices are studied via electroluminescence (EL) and photoluminescence spectroscopy over a wide range of active region compositions. It is observed that for typical nanowire plasma assisted molecular beam epitaxy growth conditions, tuning of emission to wavelengths shorter than 300 nm is hampered by the presence of an optically active defect level. We show that by increasing the AlGaN nanowire growth temperatures this defect emission can be suppressed. These findings are applied to growth of the active region of a nanowire light emitting diode, resulting in a polarization-induced nanowire light emitting diode with peak EL at 250 nm.

Exploratory analysis of glyburide as a novel therapy for preventing brain swelling.

BACKGROUND: Malignant infarction is characterized by the formation of cerebral edema, and medical treatment is limited. Preclinical data suggest that glyburide, an inhibitor of SUR1-TRPM4, is effective in preventing edema. We previously reported feasibility of the GAMES-Pilot study, a two-center prospective, open label, phase IIa trial of 10 subjects at high risk for malignant infarction based on diffusion weighted imaging (DWI) threshold of 82 cm(3) treated with RP-1127 (glyburide for injection). In this secondary analysis, we tested the hypothesis that RP-1127 may be efficacious in preventing poor outcome when compared to controls. METHODS: Controls suffering large hemispheric infarction were obtained from the EPITHET and MMI-MRI studies. We first screened subjects for controls with the same DWI threshold used for enrollment into GAMES-Pilot, 82 cm(3). Next, to address imbalances, we applied a weighted Euclidean matching. Ninety day mRS 0-4, rate of decompressive craniectomy, and mortality were the primary clinical outcomes of interest. RESULTS: The mean age of the GAMES cohort was 51 years and initial DWI volume was 102 ± 23 cm(3). After Euclidean matching, GAMES subjects showed similar NIHSS, higher DWI volume, younger age and had mRS 0-4-90% versus 50% in controls p = 0.049; with a similar trend in mRS 0-3 (40 vs. 25%; p = 0.43) and trend toward lower mortality (10 vs. 35%; p = 0.21). CONCLUSIONS: In this pilot study, RP-1127-treated subjects showed better clinical outcomes when compared to historical controls. An adequately powered and randomized phase II trial of patients at risk for malignant infarction is needed to evaluate the potential efficacy of RP-1127.

GdN nanoisland-based GaN tunnel junctions.

Tunnel junctions could have a great impact on gallium nitride and aluminum nitride-based devices such as light-emitting diodes and lasers by overcoming critical challenges related to hole injection and p-contacts. This paper demonstrates the use of GdN nanoislands to enhance interband tunneling and hole injection into GaN p-n junctions by several orders of magnitude, resulting in low tunnel junction specific resistivity (1.3 × 10(-3) Ω-cm(2)) compared to the previous results in wide band gap semiconductors. Tunnel injection of holes was confirmed by low-temperature operation of GaN p-n junction with a tunneling contact layer, and strong electroluminescence down to 20 K. The low tunnel junction resistance combined with low optical absorption loss in GdN is very promising for incorporation in GaN-based light emitters.

Mixed polarity in polarization-induced p-n junction nanowire light-emitting diodes.

Polarization-induced nanowire light emitting diodes (PINLEDs) are fabricated by grading the Al composition along the c-direction of AlGaN nanowires grown on Si substrates by plasma-assisted molecular beam epitaxy (PAMBE). Polarization-induced charge develops with a sign that depends on the direction of the Al composition gradient with respect to the [0001] direction. By grading from GaN to AlN then back to GaN, a polarization-induced p-n junction is formed. The orientation of the p-type and n-type sections depends on the material polarity of the nanowire (i.e., Ga-face or N-face). Ga-face material results in an n-type base and a p-type top, while N-face results in the opposite. The present work examines the polarity of catalyst-free nanowires using multiple methods: scanning transmission electron microscopy (STEM), selective etching, conductive atomic force microscopy (C-AFM), and electroluminescence (EL) spectroscopy. Selective etching and STEM measurements taken in annular bright field (ABF) mode demonstrate that the preferred orientation for catalyst-free nanowires grown by PAMBE is N-face, with roughly 10% showing Ga-face orientation. C-AFM and EL spectroscopy allow electrical and optical differentiation of the material polarity in PINLEDs since the forward bias direction depends on the p-n junction orientation and therefore on nanowire polarity. Specifically, C-AFM reveals that the direction of forward bias for individual nanowire LEDs changes with the polarity, as expected, due to reversal of the sign of the polarization-induced charge. Electroluminescence measurements of mixed polarity PINLEDs wired in parallel show ambipolar emission due to the mixture of p-n and n-p oriented PINLEDs. These results show that, if catalyst-free III-nitride nanowires are to be used to form polarization-doped heterostructures, then it is imperative to understand their mixed polarity and to design devices using these nanowires accordingly.

Incidental multifocal granular cell tumor in the setting of chronic gastritis discovered following gastric sleeve operation: a case report and brief review of the literature.

Granular cell tumors are uncommon neoplasms of Schwannian origin that can present nearly anywhere in the body, but are most commonly seen in the head and neck region. While the majority of these tumors are benign, a subset can behave aggressively and even have metastatic potential. We are reporting a case of a 35-year-old female with a history morbid obesity presenting for bariatric surgery (sleeve gastrectomy). Upon receiving the specimen in pathology, nodular vaguely defined lesions were identified in the gastric wall. Representative sections were submitted for microscopic examination, which revealed the incidental finding of a multifocal granular cell tumor with a background of chronic gastritis. The patient has not had any regional recurrences or metastasis in the past 2 years following the procedure.