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Search Results: 1 - 10 of 4322 matches for " Louis Guertin "
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The Cost of Prolonged Hospitalization due to Postthyroidectomy Hypocalcemia: A Case-Control Study
Navid Zahedi Niaki,Harmeet Singh,Sami P. Moubayed,Rebecca Leboeuf,Jean-Claude Tabet,Apostolos Christopoulos,Tareck Ayad,Marie-Jo Olivier,Louis Guertin,Eric Bissada
Advances in Endocrinology , 2014, DOI: 10.1155/2014/954194
Abstract: The aim of this study is to evaluate the additional costs associated with calcium monitoring and treatment as well as evaluate the incidence and predictors of postthyroidectomy hypocalcemia. Methods. This case-control study involved thyroidectomy and completion thyroidectomy patients operated on between January 2012 and August 2013. Cases were defined as requiring calcitriol supplementation, and controls did not require supplementation. Patient (age, sex), nodule (cytology, pathology), surgical data (neck dissection, parathyroid identification, and reimplantation), and hospital stay (days hospitalized in total and after drain removal) were compared. Comparisons were made using -tests and chi-square tests with an alpha of 0.05. The estimated cost associated with the extended stay was then compared with the cost of supplementation. Results. A total of 191 patients were evaluated (61 cases and 130 controls). Predictors of hypocalcemia include female age, neck dissection, and parathyroid reimplantation. Hypocalcemic patients were hospitalized for a longer period of time after drain removal (2.5 versus 0.8 days, ), and hospitalization costs after neck drain removal were higher in this group as well (8,367.32$ versus 2,534.32$, ). Conclusion. Postoperative hypocalcemia incurs significant additional health care costs at both the local and health care system levels. 1. Introduction As thyroid cancer has the most rapidly rising incidence rate of all major cancers in Canada [1], surgeons will likely be performing an increasing number of thyroidectomies in the foreseeable future. One of the major complications following completion and total thyroidectomy is postoperative hypocalcemia [2], which is mainly due to hypoparathyroidism when the parathyroid glands are put at risk of devascularization, with incidence rates of up to 33% being reported in centers where it is managed only on the basis of clinical observation and calcium monitoring [3]. Although some research has focused on developing protocols and guidelines to reduce the incidence of postoperative hypocalcemia [4–6], there is very little data on the economic impact of the monitoring and treatment of postthyroidectomy hypocalcemia in Canada. The current standard of practice at our tertiary hospital center is of postoperative serum calcium monitoring and treatment of hypocalcemia when necessary. The aim of this study is to evaluate the incidence and the predictors of postoperative hypocalcemia following thyroid surgery as well as to evaluate the additional cost of prolonged hospitalization incurred by the
Anxiolytics may promote locomotor function recovery in spinal cord injury patients
Pierre A Guertin
Neuropsychiatric Disease and Treatment , 2008,
Abstract: Pierre A GuertinNeuroscience Unit, Laval University Medical Center (CHUL), Quebec City, CanadaAbstract: Recent findings in animal models of paraplegia suggest that specific nonbenzodiazepine anxiolytics may temporarily restore locomotor functions after spinal cord injury (SCI). Experiments using in vitro models have revealed, indeed, that selective serotonin receptor (5-HTR) ligands such as 5-HTR1A agonists, known as relatively safe anxiolytics, can acutely elicit episodes of rhythmic neuronal activity refered to as fictive locomotion in isolated spinal cord preparations. Along the same line, in vivo studies have recently shown that this subclass of anxiolytics can induce, shortly after systemic administration (eg, orally or subcutaneously), some locomotor-like hindlimb movements during 45–60 minutes in completely spinal cord-transected (Tx) rodents. Using ‘knock-out’ mice (eg, 5-HTR7-/-) and selective antagonists, it has been clearly established that both 5-HTR1A and 5-HTR7 were critically involved in mediating the pro-locomotor effects induced by 8-OH-DPAT (typically referred to as a 5-HTR1A agonist) in Tx animals. Taken together, these in vitro and in vivo data strongly support the idea that 5-HTR1A agonists may eventually become constitutive elements of a novel first-in-class combinatorial treatment aimed at periodically inducing short episodes of treadmill stepping in SCI patients.Keywords: 5-HT agonists, anxiolytics, locomotion, SCI
Can the Spinal Cord Learn and Remember?
Pierre A. Guertin
The Scientific World Journal , 2008, DOI: 10.1100/tsw.2008.106
Preclinical evidence supporting the clinical development of central pattern generator-modulating therapies for chronic spinal cord-injured patients
Pierre A. Guertin
Frontiers in Human Neuroscience , 2014, DOI: 10.3389/fnhum.2014.00272
Abstract: Ambulation or walking is one of the main gaits of locomotion. In terrestrial animals, it may be defined as a series of rhythmic and bilaterally coordinated movement of the limbs which creates a forward movement of the body. This applies regardless of the number of limbs—from arthropods with six or more limbs to bipedal primates. These fundamental similarities among species may explain why comparable neural systems and cellular properties have been found, thus far, to control in similar ways locomotor rhythm generation in most animal models. The aim of this article is to provide a comprehensive review of the known structural and functional features associated with central nervous system (CNS) networks that are involved in the control of ambulation and other stereotyped motor patterns—specifically Central Pattern Generators (CPGs) that produce basic rhythmic patterned outputs for locomotion, micturition, ejaculation, and defecation. Although there is compelling evidence of their existence in humans, CPGs have been most studied in reduced models including in vitro isolated preparations, genetically-engineered mice and spinal cord-transected animals. Compared with other structures of the CNS, the spinal cord is generally considered as being well-preserved phylogenetically. As such, most animal models of spinal cord-injured (SCI) should be considered as valuable tools for the development of novel pharmacological strategies aimed at modulating spinal activity and restoring corresponding functions in chronic SCI patients.
Central Pattern Generator for Locomotion: Anatomical, Physiological, and Pathophysiological Considerations
Pierre A. Guertin
Frontiers in Neurology , 2013, DOI: 10.3389/fneur.2012.00183
Abstract: This article provides a perspective on major innovations over the past century in research on the spinal cord and, specifically, on specialized spinal circuits involved in the control of rhythmic locomotor pattern generation and modulation. Pioneers such as Charles Sherrington and Thomas Graham Brown have conducted experiments in the early twentieth century that changed our views of the neural control of locomotion. Their seminal work supported subsequently by several decades of evidence has led to the conclusion that walking, flying, and swimming are largely controlled by a network of spinal neurons generally referred to as the central pattern generator (CPG) for locomotion. It has been subsequently demonstrated across all vertebrate species examined, from lampreys to humans, that this CPG is capable, under some conditions, to self-produce, even in absence of descending or peripheral inputs, basic rhythmic, and coordinated locomotor movements. Recent evidence suggests, in turn, that plasticity changes of some CPG elements may contribute to the development of specific pathophysiological conditions associated with impaired locomotion or spontaneous locomotor-like movements. This article constitutes a comprehensive review summarizing key findings on the CPG as well as on its potential role in Restless Leg Syndrome, Periodic Leg Movement, and Alternating Leg Muscle Activation. Special attention will be paid to the role of the CPG in a recently identified, and uniquely different neurological disorder, called the Uner Tan Syndrome.
Spinal Cord Injury Research in Mice: 2008 Review
Inge Steuer,Pierre A. Guertin
The Scientific World Journal , 2009, DOI: 10.1100/tsw.2009.63
Prevalence of K-RAS Codons 12 and 13 Mutations in Locally Advanced Head and Neck Squamous Cell Carcinoma and Impact on Clinical Outcomes
Eric Bissada,Olivier Abboud,Zahi Abou Chacra,Louis Guertin,Xiaoduan Weng,Phuc Félix Nguyen-Tan,Jean-Claude Tabet,ève Thibaudeau,Louise Lambert,Marie-Lise Audet,Bernard Fortin,Denis Soulières
International Journal of Otolaryngology , 2013, DOI: 10.1155/2013/848021
Abstract: Background. RAS gene mutations have an impact on treatment response and overall prognosis for certain types of cancer. Objectives. To determine the prevalence and impact of K-RAS codons 12 and 13 mutations in patients with locally advanced HNSCC treated with primary or adjuvant chemo-radiation. Methods. 428 consecutive patients were treated with chemo-radiation therapy and followed for a median of 37 months. From these, 199 paraffin embedded biopsy or surgical specimens were retrieved. DNA was isolated and analyzed for K-RAS mutational status. Results. DNA extraction was successful in 197 samples. Of the 197 specimens, 3.5% presented K-RAS codon 12 mutations. For mutated cases and non-mutated cases, complete initial response to chemoradiation therapy was 71 and 73% ( ). LRC was respectively 32 and 83% ( ), DFS was 27 and 68% ( ), distant metastasis-free survival was 100 and 81% ( ) and OS was 57 and 65% ( ) at three years. K-Ras codon 13 analysis revealed no mutation. Conclusion. K-RAS codon 12 mutational status, although not associated with a difference in response rate, may influence the failure pattern and the type of therapy offered to patients with HNSCC. Our study did not reveal any mutation of K-RAS codon 13. 1. Introduction Head and neck squamous cell carcinoma (HNSCC) accounts for 47?000 new malignancies diagnosed each year in the USA and is the sixth most common human neoplasm, representing about 3% of all cancers [1]. Despite efforts to improve conventional treatment, survival rates for these cancers have not changed significantly over the past decade. Initial evaluation of patients includes clinical assessment, study of tumor histological characteristics and tumor grading, as well as local-regional and distant metastasis status. Traditional clinical, radiological, and histopathological characteristics are however limited in their ability to accurately predict response to treatment. This has motivated many researchers to identify molecular characteristics that may influence overall prognosis. A recent interest in molecular biology and genetics is motivated by the belief that understanding the origins of cancer can lead to more logical means of treating malignancies [2]. Identification of molecular events that lead to HNSCC may represent a key to predicting biological behaviour and may consequently lead to new treatment modalities that could lead to increases in survival rates. [3, 4]. Despite the recent progress in the field of molecular biology, clinicians need more tools to predict response to therapy or to identify patients at high risk of
Chromatin Landscape Dictates HSF Binding to Target DNA Elements
Michael J. Guertin,John T. Lis
PLOS Genetics , 2010, DOI: 10.1371/journal.pgen.1001114
Abstract: Sequence-specific transcription factors (TFs) are critical for specifying patterns and levels of gene expression, but target DNA elements are not sufficient to specify TF binding in vivo. In eukaryotes, the binding of a TF is in competition with a constellation of other proteins, including histones, which package DNA into nucleosomes. We used the ChIP-seq assay to examine the genome-wide distribution of Drosophila Heat Shock Factor (HSF), a TF whose binding activity is mediated by heat shock-induced trimerization. HSF binds to 464 sites after heat shock, the vast majority of which contain HSF Sequence-binding Elements (HSEs). HSF-bound sequence motifs represent only a small fraction of the total HSEs present in the genome. ModENCODE ChIP-chip datasets, generated during non-heat shock conditions, were used to show that inducibly bound HSE motifs are associated with histone acetylation, H3K4 trimethylation, RNA Polymerase II, and coactivators, compared to HSE motifs that remain HSF-free. Furthermore, directly changing the chromatin landscape, from an inactive to an active state, permits inducible HSF binding. There is a strong correlation of bound HSEs to active chromatin marks present prior to induced HSF binding, indicating that an HSE's residence in “active” chromatin is a primary determinant of whether HSF can bind following heat shock.
Justifying Tolerance in Liberal Societies: The Need for Public Morality  [PDF]
Louis Tietje
Open Journal of Philosophy (OJPP) , 2012, DOI: 10.4236/ojpp.2012.21002
Abstract: One of the most important assumptions in liberal societies is that citizens should be tolerant of a diversity of values. We are challenged by this assumption to justify restraint when we confront what we oppose, disapprove of, or perceive to be immoral, even if we have the power to suppress perceived immoralities. Based on the work of Elliot Turiel, Jonathan Haidt, and Gerald Gaus, the argument developed in this article is that the best way to address the challenge is to distinguish between public morality and other normative categories such as convention and private morality. Public morality circumscribes what should not be publicly tolerated. Conventional and private immoralities that are not prohibited by public morality should be tolerated.
Logical Difficulty from Combining Counterfactuals in the GHZ-Bell Theorems  [PDF]
Louis Sica
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.410A3012

In eliminating the fair sampling assumption, the Greenberger, Horne, Zeilinger (GHZ) theorem is believed to confirm Bell’s historic conclusion that local hidden variables are inconsistent with the results of quantum mechanics. The GHZ theorem depends on predicting the results of sets of measurements of which only one may be performed. In the present paper, the noncommutative aspects of these unperformed measurements are critically examined. Classical examples and the logic of the GHZ construction are analyzed to demonstrate that combined counterfactual results of noncommuting operations are in general logically inconsistent with performed measurement sequences whose results depend on noncommutation. The Bell theorem is also revisited in the light of this result. It is concluded that negative conclusions regarding local hidden variables do not follow from the GHZ and Bell theorems as historically reasoned.

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