Publications by authors named "Nason R"

Complexity is a form of system that is relevant in virtually all aspects and levels of healthcare. The importance and relevance of the science of complexity for healthcare has been written about extensively for over two decades. The problem this article addresses is that complex systems and how to manage them still appear to be relatively unknown nor well understood by most stakeholders of healthcare.

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Mucins and glycoproteins with mucin-like regions contain densely O-glycosylated domains often found in tandem repeat (TR) sequences. These O-glycodomains have traditionally been difficult to characterize because of their resistance to proteolytic digestion, and knowledge of the precise positions of O-glycans is particularly limited for these regions. Here, we took advantage of a recently developed glycoengineered cell-based platform for the display and production of mucin TR reporters with custom-designed O-glycosylation to characterize O-glycodomains derived from mucins and mucin-like glycoproteins.

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The human genome contains at least 35 genes that encode Golgi sulfotransferases that function in the secretory pathway, where they are involved in decorating glycosaminoglycans, glycolipids, and glycoproteins with sulfate groups. Although a number of important interactions by proteins such as selectins, galectins, and sialic acid-binding immunoglobulin-like lectins are thought to mainly rely on sulfated O-glycans, our insight into the sulfotransferases that modify these glycoproteins, and in particular GalNAc-type O-glycoproteins, is limited. Moreover, sulfated mucins appear to accumulate in respiratory diseases, arthritis, and cancer.

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Objective: The Interagency Integrated Triage Tool (IITT) is a novel, three-tier triage system recommended by the World Health Organization. The present study sought to assess the validity and reliability of a pilot version of the tool in a resource-limited ED in regional Papua New Guinea.

Methods: This pragmatic prospective observational study, conducted at Mount Hagen Provincial Hospital, commenced 1 month after IITT implementation.

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Mucins are a large family of heavily O-glycosylated proteins that cover all mucosal surfaces and constitute the major macromolecules in most body fluids. Mucins are primarily defined by their variable tandem repeat (TR) domains that are densely decorated with different O-glycan structures in distinct patterns, and these arguably convey much of the informational content of mucins. Here, we develop a cell-based platform for the display and production of human TR O-glycodomains (~200 amino acids) with tunable structures and patterns of O-glycans using membrane-bound and secreted reporters expressed in glycoengineered HEK293 cells.

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Article Synopsis
  • Siglecs are immune system receptors that bind to specific sialic acid-containing sugars, influencing immune cell functions, but their exact binding preferences and mechanisms are not completely understood.
  • Researchers created modified human HEK293 cells to study how different sialyltransferase genes and sulfotransferases affect the binding of Siglecs to various types of sialoglycans on cell surfaces.
  • The study revealed distinct binding patterns for Siglecs, highlighting how sulfation alters binding preferences, with a specific epitope linked to Siglec-3 implicated in late-onset Alzheimer's disease, showcasing the potential for this research to inform future discoveries in immunology and disease.
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The structural diversity of glycans on cells-the glycome-is vast and complex to decipher. Glycan arrays display oligosaccharides and are used to report glycan hapten binding epitopes. Glycan arrays are limited resources and present saccharides without the context of other glycans and glycoconjugates.

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Most proteins trafficking the secretory pathway of metazoan cells will acquire GalNAc-type O-glycosylation. GalNAc-type O-glycosylation is differentially regulated in cells by the expression of a repertoire of up to twenty genes encoding polypeptide GalNAc-transferase isoforms (GalNAc-Ts) that initiate O-glycosylation. These GalNAc-Ts orchestrate the positions and patterns of O-glycans on proteins in coordinated, but poorly understood ways - guided partly by the kinetic properties and substrate specificities of their catalytic domains, as well as by modulatory effects of their unique GalNAc-binding lectin domains.

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Background: Follicular and Hürthle cell neoplasms are diagnostic challenges. This prospective study was designed to evaluate the efficacy of [18F]-2-fluoro-2-deoxy--glucose (FDG) positron emission tomography/computed tomography (PET/CT) in predicting the risk of malignancy in follicular/Hürthle cell neoplasms.

Materials And Methods: Fifty thyroid nodules showing follicular/Hürthle cell neoplasm on prior ultrasonography guided fine needle aspiration cytology (FNAC) were recruited into this study.

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Objective: Thyroid prognostic nomogram can be applied across different histological types for predicting the individualized risk of death from thyroid cancer. The objective of this study was to compare the strength of our recently published thyroid prognostic nomogram with 12 existing staging systems to predict the risk of death from thyroid cancer.

Method: This study included 1900 thyroid cancer patients, from a population based cohort of 2296 patients, on whom adequate staging information was available.

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Objective: Follicular (FN) and Hürthle cell neoplasms (HCN) are considered indeterminate on thyroid fine needle aspiration cytology and are preoperative diagnostic challenges. The role of [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) in characterizing indeterminate thyroid nodules remains equivocal, because of the increased FDG uptake by some benign thyroid nodules. The objective of this study was to compare the FDG positron emission tomography/computerized tomography (PET/CT) characteristics of follicular (FA) and Hürthle cell adenomas (HCA).

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Loss of tumor suppressor proteins, such as the retinoblastoma protein (Rb), results in tumor progression and metastasis. Metastasis is facilitated by low oxygen availability within the tumor that is detected by hypoxia inducible factors (HIFs). The HIF1 complex, HIF1α and dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT), is the master regulator of the hypoxic response.

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Background: Age is a critical factor in outcome for patients with well-differentiated thyroid cancer. Currently, age 45 years is used as a cutoff in staging, although there is increasing evidence to suggest this may be too low. The aim of this study was to assess the potential for changing the cut point for the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) staging system from 45 years to 55 years based on a combined international patient cohort supplied by individual institutions.

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Introduction: The time of drawing pre-incision intraoperative parathyroid hormone (ioPTH) is crucial to provide the right baseline for post-excision PTH measurement. The objective of this study was to identify the optimal time and the numbers of baseline PTH samples that best predict excision of all hypercellular parathyroid tissue when compared with 10-min post-excision PTH level.

Materials And Methods: In this prospective study, two pre-incision (pre-induction and 10-min post-induction) baseline ioPTH samples along with pre- and post-excision ioPTH were collected and analyzed for 352 parathyroidectomies in 341 patients for sporadic primary hyperparathyroidism at a University hospital.

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Background And Objectives: AJCC-TNM Stage II well-differentiated thyroid cancer (WDTC) comprises T2N0M0 tumors in patients ≥45 years of age or metastatic WDTC in patients younger than 45 years. The objectives of this study were to assess the oncological outcome of stage II WDTC and to compare the oncological outcome of metastatic WDTC in patient younger (stage II) and older (stage IVC) than 45 years.

Methods: This study involved review of clinical presentation and oncological outcome of population cohort of 2,128 consecutive WDTC, diagnosed during 1970-2010 that includes 215 Stage II WDTC and 61 metastatic WDTC.

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Objective: Age is integrated in most risk stratification systems for well-differentiated thyroid cancer (WDTC). The most appropriate age threshold for stage grouping of WDTC is debatable. The objective of this study was to evaluate the best age threshold for stage grouping by comparing multivariable models designed to evaluate the independent impact of various prognostic factors, including age based stage grouping, on the disease specific survival (DSS) of our population-based cohort.

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In North America, the incidence of thyroid cancer is increasing by over 6% per year. We studied the trends and factors influencing thyroid cancer incidence, its clinical presentation, and treatment outcome during 1970-2010 in a population-based cohort of 2306 consecutive thyroid cancers in Canada, that was followed up for a median period of 10.5 years.

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Context: Thyroid cancers represent a conglomerate of diverse histological types with equally variable prognosis. There is no reliable prognostic model to predict the risks of relapse and death for different types of thyroid cancers.

Objective: The purpose of this study was to build prognostic nomograms to predict individualized risks of relapse and death of thyroid cancer within 10 years of diagnosis based on patients' prognostic factors.

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Background: The consolidation of acute care surgery (ACS) services at 3 of 6 hospitals in a Canadian health region sought to alleviate a relative shortage of surgeons able to take emergency call. We examined how this affected patient access and outcomes.

Methods: Using the generalized linear model and statistical process control, we analyzed ACS-related episodes that occurred between 39 months prior to and 17 months after the model's implementation (n = 14,713).

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Well-differentiated thyroid carcinoma (WDTC) represents a group of thyroid cancers with excellent prognosis. Age, a well-recognized risk factor for WDTC, has been consistently included in various prognostic scoring systems. An age threshold of 45 years is currently used by the American Joint Cancer Committee-TNM staging system for the risk stratification of patients.

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Sarcomas are malignant neoplasms originating from mesodermal tissues and constitute less than 1% of body's tumors, including those of the head and neck region. 5-15% of adult sarcomas are in the head and neck region (20% from bones and cartilages and 80% in soft tissues). Commonly encountered sarcomas in the head and neck region are - osteosarcoma, rhabdomyosarcoma, malignant fibrous histiocytoma, fibrosarcoma and angiosarcoma.

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Objectives: Clinicians have long noted that infected cholesteatomas are more aggressive than uninfected ones without data to support these observations. The purpose of this study is to determine the etiological role of biofilm forming P. aeruginosa (PA) and the virulence factor, type IV pili (TFP), in the pathogenesis of experimental cholesteatomas.

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