Publications by authors named "Lazarus C"

Radiofrequency (RF) ablation to perform pulmonary vein isolation (PVI) for the treatment of atrial fibrillation involves some risk to collateral structures, including the esophagus. Proactive esophageal cooling using a dedicated device has been granted marketing authorization by the Food and Drug Administration (FDA) to reduce the risk of ablation-related esophageal injury due to RF cardiac ablation procedures, and more recent data also suggest that esophageal cooling may contribute to improved long-term efficacy of treatment. A mechanistic underpinning explaining these findings exists through the quantification of lesion placement contiguity defined as the Continuity Index (CI).

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Background: Proactive esophageal cooling is FDA cleared to reduce the likelihood of esophageal injury during radiofrequency ablation for treatment of atrial fibrillation (AF). Long-term follow-up data have also shown improved freedom from arrhythmia with proactive esophageal cooling compared to luminal esophageal temperature (LET) monitoring during pulmonary vein isolation (PVI). One hypothesized mechanism is improved lesion contiguity (as measured by the Continuity Index) with the use of cooling.

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The Guiana Shield, a small region of South America, is currently one of the main hotspots of malaria transmission on the continent. This Amazonian area is characterised by remarkable socioeconomic, cultural, health, and political heterogeneity and a high degree of regional and cross-border population mobility, which has contributed to the increase of malaria in the region in the past few years. In this context, regional cooperation to control malaria represents both a challenge and an indispensable initiative.

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Article Synopsis
  • This study aims to develop a deep learning method for detecting pulmonary embolism (PE) and calculating its severity using specific metrics on 3D computed tomography pulmonary angiography (CTPA) images with few annotations.
  • The approach includes a series of steps: identifying blood clots, classifying PE presence, and estimating both the Qanadli score and right-to-left ventricle diameter (RV/LV) ratio, utilizing data from a large set of patient examinations.
  • Results showed promising accuracy for PE classification with an area under the curve (AUC) of about 0.87, and solid regression outcomes for estimating severity scores, indicating potential use of AI tools in clinical settings, though further research is needed. *
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We developed mathematical models to analyze a large dengue virus (DENV) epidemic in Reunion Island in 2018-2019. Our models captured major drivers of uncertainty including the complex relationship between climate and DENV transmission, temperature trends, and underreporting. Early assessment correctly concluded that persistence of DENV transmission during the austral winter 2018 was likely and that the second epidemic wave would be larger than the first one.

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Background: South Africa (SA) is on the brink of implementing workplace-based assessments (WBA) in all medical specialist training programmes in the country. Despite the fact that competency-based medical education (CBME) has been in place for about two decades, WBA offers new and interesting challenges. The literature indicates that WBA has resource, regulatory, educational and social complexities.

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Aim: Because the tongue is a midline structure, studies on the neural correlates of lateralized tongue function are challenging and remain limited. Patients with tongue cancer who undergo unilateral partial glossectomy may be a unique cohort to study tongue-associated cortical activation, particularly regarding brain hemispheric lateralization. This longitudinal functional magnetic resonance imaging (fMRI) study investigated cortical activation changes for three tongue tasks before and after left-sided partial glossectomy in patients with squamous cell carcinoma of the tongue.

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Article Synopsis
  • This study aimed to create a method for generating synthetic MR images of macrotrabecular-massive hepatocellular carcinoma (MTM-HCC) to improve imaging capabilities.* -
  • Researchers used MR images from 91 patients with MTM-HCC and a separate group of 67 patients, employing a 3-step pipeline to create realistic synthetic images and evaluating them with the help of radiologists.* -
  • The results showed that 1000 synthetic images were generated with consistent quality, achieving a score of 0.64 in evaluations, suggesting promising potential for these images in automatic diagnosis but indicating the need for further research.*
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Recent studies have identified serotonylation of glutamine-5 on histone H3 (H3Q5ser) as a novel posttranslational modification (PTM) associated with active transcription. While H3Q5ser is known to be installed by tissue transglutaminase 2 (TGM2), the substrate characteristics affecting deposition of the mark, at the level of both chromatin and individual nucleosomes, remain poorly understood. Here, we show that histone serotonylation is excluded from constitutive heterochromatic regions in mammalian cells.

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Heterologous expression of nrps33, a nonribosomal peptide synthetase gene, from Paecilomyces cinnamomeus BCC 9616 in Saccharomyces cerevisiae unexpectedly resulted in the accumulation of anthranilic acid, an intermediate in tryptophan biosynthesis. Based on transcriptomic and real-time quantitative polymerase chain reaction (RT-qPCR) results, expression of nrps33 affected the transcription of tryptophan biosynthesis genes especially TRP1 which is also the selectable auxotrophic marker for the expression vector used in this work. The product of nrps33 could inhibit the activity of Trp4 involved in the conversion of anthranilate to N-(5'-phosphoribosyl)anthranilate and therefore caused the accumulation of anthranilic acid.

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Alternapyrone is a highly methylated polyene α-pyrone biosynthesised by a highly reducing polyketide synthase. Mutations of the catalytic dyad residues, H1578A/Q and E1604A, of the -methyltransferase domain resulted in either significantly reduced or no production of alternapyrone, indicating the importance of -methylation for alternapyrone biosynthesis.

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A suite of molecular techniques have been developed in recent decades, which allow gene clusters coding for the biosynthesis of fungal natural products to be investigated and characterized in great detail. Many of these involve the manipulation of the native producer, for example, to increase yields of natural products or investigate the biosynthetic pathway through gene disruptions. However, an alternative and powerful means of investigating biosynthetic pathways, which does not rely on a cooperative native host, is the refactoring and heterologous expression of pathways in a suitable host strain.

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Background: Swallowing therapy is commonly provided as a treatment to lessen the risk or severity of dysphagia secondary to radiotherapy (RT) for head and neck cancer (HNC); however, best practice is not yet established. This trial will compare the effectiveness of prophylactic (high and low intensity) versus reactive interventions for swallowing in patients with HNC undergoing RT.

Methods: This multi-site, international randomized clinical trial (RCT) will include 952 adult patients receiving radiotherapy for HNC and who are at high risk for post-RT dysphagia.

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Introduction: Recognizing the need to teach concepts of health equity, diversity, and inclusion as a part of medical students' preclinical training, we developed a series of workshops in the first year of medical school that introduced students to issues of discrimination and inequity and their effects on health outcomes. This student-led, faculty-supported project, known as Critical Consciousness in Medicine (CCM), adopted critical consciousness as a guiding principle for student learning.

Methods: Over the course of the 2018-2019 academic year, student leaders developed and delivered five 2-hour workshops to 197 first-year students, with the assistance of student facilitators and input and guidance from faculty advisors.

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Background: After head and neck cancer (HNC) treatment, dysgeusia may be a barrier to oral intake. In this exploratory study, we prospectively examined taste perception, clinician-rated (CRO) and patient-reported (PRO) taste changes and their effect on oral intake postradiotherapy.

Methods: Twenty-eight patients were assessed at baseline, treatment weeks 2 and 4, and 1, 3, and 6 months post-treatment using a whole-mouth taste test and associated CRO and subjective PRO measures.

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The use of filamentous fungi as cellular factories, where natural product pathways can be refactored and expressed in a host strain, continues to aid the field of natural product discovery. Much work has been done to develop host strains which are genetically tractable, and for which there are multiple selectable markers and controllable expression systems. To fully exploit these strains, it is beneficial to understand their natural metabolic capabilities, as such knowledge can rule out host metabolites from analysis of transgenic lines and highlight any potential interplay between endogenous and exogenous pathways.

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Fusarochromene isolated from the plant pathogenic fungus, Fusarium sacchari is closely related to a group of mycotoxins including fusarochromanone previously isolated from various Fusaria spp. Despite their assumed polyketide biogenesis, incorporation studies with 13C-labelled acetate, glycerol and tryptophans show that fusarochromene is unexpectedly derived via oxidative cleavage of the aromatic amino acid tryptophan. A putative biosynthetic gene cluster has been identified.

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Menisporopsin A is a fungal bioactive macrocyclic polylactone, the biosynthesis of which requires only reducing (R) and nonreducing (NR) polyketide synthases (PKSs) to guide a series of esterification and cyclolactonization reactions. There is no structural information pertaining to these PKSs. Here, we report the solution characterization of singlet and doublet acyl carrier protein (ACP and ACP -ACP )-thioesterase (TE) domains from NR-PKS involved in menisporopsin A biosynthesis.

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This erratum notifies the readers of the Dysphagia journal of an error in the original published version of this manuscript. In that manuscript, a previously available open source spreadsheet tool was used to calculate the position of the posterior laryngeal air column on lateral view videofluoroscopic images as a proxy for the bottom of the pharynx. We have subsequently been made aware of an error in the mathematical formula built into the spreadsheet, which resulted in a reversal of the results for the X and Y planes of measurement.

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Purpose Learning a motor skill and regaining a motor skill after it is lost are key tenets to the field of speech-language pathology. Motor learning and relearning have many theoretical underpinnings that serve as a foundation for our clinical practice. This review article applies selective motor learning theories and principles to feeding and swallowing across the life span.

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We have recently proposed a new optimization algorithm called SPARKLING (Spreading Projection Algorithm for Rapid K-space sampLING) to design efficient compressive sampling patterns for magnetic resonance imaging (MRI). This method has a few advantages over conventional non-Cartesian trajectories such as radial lines or spirals: i) it allows to sample the k-space along any arbitrary density while the other two are restricted to radial densities and ii) it optimizes the gradient waveforms for a given readout time. Here, we introduce an extension of the SPARKLING method for 3D imaging by considering both stacks-of-SPARKLING and fully 3D SPARKLING trajectories.

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The safe and secure containment of infectious poliovirus (PV) in facilities where live PV are handled is the condition to achieve and maintain poliomyelitis eradication. Despite precautions to minimize the risk of release of PV from such facilities to the environment, breaches of containment have already been documented. Here, we report the management of an incident that occurred on 30 November 2018 in a French vaccine manufacturing plant.

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Purpose As the COVID-19 pandemic has unfolded, there has been growing recognition of risks to frontline health care workers. When caring for patients with tracheostomy, speech-language pathologists have significant exposure to mucosal surfaces, secretions, and aerosols that may harbor the SARS-CoV-2 virus. This tutorial provides guidance on practices for safely performing patient evaluation and procedures, thereby reducing risk of infection.

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Importance: Incorporation of patient perspectives, or patient-reported outcomes, in functional outcome measures has been gaining prominence in the literature on reconstructive surgery.

Objective: To create and validate an instrument for measuring the main functional areas of concern for patients with head and neck cancer.

Design, Setting, And Participants: This 4-phase mixed-methods qualitative study was conducted from July 1, 2013, to June 30, 2016, in a quaternary head and neck oncology center in Edmonton, Alberta, Canada.

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A novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) causing a cluster of respiratory infections (coronavirus disease 2019, COVID-19) in Wuhan, China, was identified on 7 January 2020. The epidemic quickly disseminated from Wuhan and as at 12 February 2020, 45,179 cases have been confirmed in 25 countries, including 1,116 deaths. Strengthened surveillance was implemented in France on 10 January 2020 in order to identify imported cases early and prevent secondary transmission.

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