Publications by authors named "Colwell N"

Background: Arteriovenous malformations (AVMs) are abnormal direct connections between arterial and venous systems, without an interposed capillary bed. This permits high-flow arteriovenous shunting, which precipitates structural changes in the afferent and efferent vessels, namely arterial smooth muscle hyperplasia and thinning of venous walls. Patients with intracranial AVMs typically present with a haemorrhage, headache or seizure.

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Background: Gliosarcoma, an isocitrate dehydrogenase wildtype (IDH-WT) variant of glioblastoma, is defined by clonal biphasic differentiation into gliomatous and sarcomatous components. While the transformation from a glioblastoma to gliosarcoma is uncommon, the subsequent transformation to osteosarcoma is rare but may provide additional insights into the biology of these typically distinct cancers. We observed a patient initially diagnosed with glioblastoma, that differentiated into gliosarcoma at recurrence, and further evolved to osteosarcoma at the second relapse.

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Many of the health-associated impacts of the microbiome are mediated by its chemical activity, producing and modifying small molecules (metabolites). Thus, microbiome metabolite quantification has a central role in efforts to elucidate and measure microbiome function. In this review, we cover general considerations when designing experiments to quantify microbiome metabolites, including sample preparation, data acquisition and data processing, since these are critical to downstream data quality.

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Unlabelled: A brain abscess is an enclosed focal infection within the brain that is either initiated by haematogenous seeding or spreads contiguously from oto-sinusitis, local trauma or neurosurgery. We describe the case of a 71-year-old man presenting with acute confusion and unilateral neurology in the absence of systemic signs of sepsis or associated laboratory biomarkers. While his initial clinical presentation mimicked an acute cerebrovascular event or brain tumour, he was subsequently diagnosed with a particularly large spherical temporal lobe brain abscess of 5 cm diameter on neuroimaging.

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Primary subglottic carcinoma is a rare subgroup of laryngeal malignancy with exact incidence unknown due to the lack of a standard definition of its anatomic boundaries. Early-stage subglottic carcinoma can be treated with either primary radiation or surgery with similar overall survival rates. Most patients present at an advanced stage due to a paucity of symptoms, and these patients are treated in a multidisciplinary fashion.

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Background: Lipid disorders are now considered causal for atherosclerotic cardiovascular disease (ASCVD) which remains one of the most important contributors to morbidity and mortality in the developed world. Identification and early treatment of lipid disarrays remains the cornerstone of good clinical practice to prevent, halt and even reverse ASCVD. Guidelines for lipid management are imperative to help promote good clinical practice.

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Article Synopsis
  • * He had a history of a heart issue due to cocaine use, which led to ischaemic cardiomyopathy, resulting in a reduced heart function (LVEF of 45%).
  • * Following an hour of dangerous heart rhythms and asystole, he regained consciousness after receiving atropine for extreme bradycardia, likely caused by increased vagal tone.
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Background: Amphetamine use causes cardiomyopathy via catecholamine-mediated effects such as tachycardia, hypertension, vasoconstriction, and direct cardio-toxic effects. Traditionally, an increased risk of haemorrhagic stroke is associated with amphetamine use. However, up to one-third of stimulant-associated cardiomyopathy patients have left ventricular (LV) thrombus formation leading to an increased risk of systemic embolization.

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Introduction: Epilepsy surgery continues to be profoundly underutilized despite its safety and effectiveness. We sought to investigate factors that may contribute to this phenomenon, with a particular focus on the antecedent underutilization of appropriate preoperative studies.

Methods: We reviewed patient data from a pediatric epilepsy clinic over an 18-month period.

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The visual system, consisting of the eyes and the visual pathways of the brain, receives and interprets light from the environment so that we can perceive the world around us. A wide variety of disorders can affect human vision, ranging from ocular to neurologic to systemic in nature. While other noninvasive imaging techniques such as optical coherence tomography and ultrasound can image particular sections of the visual system, magnetic resonance imaging (MRI) offers high resolution without depth limitations.

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Patients with drug-resistant epilepsy (DRE) rarely achieve seizure freedom with medical therapy alone. Despite being safe and effective for select patients with DRE, epilepsy surgery remains heavily underutilized. Multiple studies have indicated that the overall rates of surgery in patients with DRE have stagnated in recent years and may be decreasing, even when hospitalizations for epilepsy-related problems are on the rise.

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Introduction: Minimal research has been conducted on the prescribing patterns of emergency room physicians. The opioid epidemic is a well-known public health crisis and increased knowledge of providers' tendencies to prescribe opioids over other analgesia may help to update guidelines, improve patient safety, and lower the amount of opioid diversion and death from overdose. The purpose of this study was to determine the association between patient visit demographics and prescribed opiate analgesics.

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Poly- adenosine diphosphate (ADP)-ribose (PAR) is a polymer synthesized as a posttranslational modification by some poly (ADP-ribose) polymerases (PARPs), namely PARP-1, PARP-2, tankyrase-1, and tankyrase-2 (TNKS-1/2). PARP-1 is nuclear and has also been detected in extracellular vesicles. PARP-2 and TNKS-1/2 are distributed in nuclei and cytoplasm.

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OBJECTIVENutritional deficiency negatively affects outcomes in many health conditions. In spine surgery, evidence linking preoperative nutritional deficiency to postoperative surgical site infection (SSI) has been limited to small retrospective studies. Authors of the current study analyzed a large consecutive cohort of patients who had undergone elective spine surgery to determine the relationship between a serum biomarker of nutritional status (preoperative prealbumin levels) and SSI.

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Background: Standard therapy for chordoma consists of surgical resection followed by high-dose irradiation. Protein phosphatase 2A (PP2A) is a ubiquitously expressed serine/threonine phosphatase involved in signal transduction, cell cycle progression, cell differentiation, and DNA repair. LB100 is a small-molecule inhibitor of PP2A designed to sensitize cancer cells to DNA damage from irradiation and chemotherapy.

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Glioblastoma is the most common and aggressive malignant primary brain tumor. Cellular heterogeneity is a characteristic feature of the disease and contributes to the difficulty in formulating effective therapies. Glioma stem-like cells (GSCs) have been identified as a subpopulation of tumor cells that are thought to be largely responsible for resistance to treatment.

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Aims: We assessed adherence to European Society of Cardiology heart rate guidelines (i.e. heart rates less than 70 bpm) in patients with chronic stable heart failure.

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The Arnett Caregiver Interaction Scale (CIS) has been widely used in research studies to measure the quality of caregiver-child interactions. The scale was modeled on a well-established theory of parenting, but there are few psychometric studies of its validity. We applied factor analyses and item response theory methods to assess the psychometric properties of the Arnett CIS in a national sample of toddlers in home-based care and preschoolers in center-based care from the Early Childhood Longitudinal Study-Birth Cohort.

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Hereditary haemorrhagic telangiectasia (HHT) is a group of autosomal dominant disorders of vascular structure. The Irish National Centre for HHT at the Mercy University Hospital, Cork, Ireland was founded in 2003. From 2003 to 2008, screening of 164 patients with contrast echocardiography, thoracic computerised tomography (CT) and cerebral magnetic resonance imaging (MRI) has identified 88 patients with definite HHT, 72 (82%) of whom had epistaxis, 70 (80%) had telangiectasia and 81 (92%) had a first-degree relative with HHT.

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In Ireland, cardiovascular disease is a major cause of death. However, blood pressure (BP) goal achievement is unsatisfactory. The authors aimed to document BP control and increase awareness.

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Contemporary Irish data on the prevalence of major cardiovascular disease (CVD) risk factors are sparse. The primary aims of this study were (1) to estimate the prevalence of major cardiovascular disease risk factors, including Type 2 Diabetes Mellitus, in the general population of men and women between the ages of 50 and 69 years; and (2) to estimate the proportion of individuals in this age group at high absolute risk of cardiovascular disease events on the basis of pre-existing cardiovascular disease or as defined by the Framingham equation. Participants were drawn from the practice lists of 17 general practices in Cork and Kerry using stratified random sampling.

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A monoclonal IgG isolated from a patient with multiple myeloma has been shown to bind to exosite II of thrombin, prolong both the thrombin time and the activated partial thromboplastin time (aPTT) when added to normal plasma, and alter the kinetics of hydrolysis of synthetic peptide substrates. Although the IgG does not affect cleavage of fibrinogen by thrombin, it increases the rate of inhibition of thrombin by purified antithrombin approximately 3-fold. Experiments with plasma immunodepleted of antithrombin or heparin cofactor II confirm that prolongation of the thrombin time requires antithrombin.

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Pancreatic cholesterol esterase is one of the enzymes that plays a pivotal role in cholesterol absorption. Differences in the genotype of this enzyme could affect the susceptibility of individuals to dyslipidemia and/or cardiovascular disease. We undertook this study to investigate if any correlation exists between restriction fragment length polymorphism in the human pancreatic cholesterol esterase gene and serum lipid levels.

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A variety of sulphated polyanions in addition to heparin and dermatan sulphate stimulate the inhibition of thrombin by heparin cofactor II (HCII). Previous investigations indicated that the binding sites on HCII for heparin and dermatan sulphate overlap but are not identical. In this study we determined the concentrations (IC50) of various polyanions required to stimulate thrombin inhibition by native recombinant HCII in comparison with three recombinant HCII variants having decreased affinity for heparin (Lys-173-->Gln), dermatan sulphate (Arg-189-->His), or both heparin and dermatan sulphate (Lys-185-->Asn).

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