Studies on the pharmacology of locomotion in adult chronic spinal cat

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Breast Cancer in Hong Kong, Southern China: The First Population-Based Analysis of Epidemiological Characteristics, Stage-Specific, Cancer-Specific, and Disease-Free Survival in Breast Cancer Patients: 1997–2001

Background: Cancer registries have been set up worldwide to provide information for cancer health planning. There are known variations in breast cancer incidence and mortality worldwide. However, breast cancer incidence, pathological characteristics, and survival data is still underreported in Asian countries. This is the first comprehensive population-based breast cancer study performed using population database of the Hong Kong Cancer Registry. Methods: A retrospective review of medical records of 8,961 subjects who were diagnosed with breast cancer between January 1, 1997 to December 31, 2001 and followed up to December 31, 2007. Descriptive statistics were employed to analyze the epidemiological and clinical data. Estimates of overall, disease-free, and cancer-specific survival at 5 years were estimated by the Kaplan-Meier method and stage-specific relative survival rates were calculated. Results: A total of 7,630 breast cancer patients' medical records and dataset were available during this period, and 7,449 subjects were eligible for the final analysis. Median follow-up was 84 months. A total of 47.4% were diagnosed with breast cancer at age 49 years and younger;22.2%, 46.9%, 10.8%, and 4.1% presented at stages I, II, III, and IV, respectively. A total of 53.5% had ER-positive cancer, and 20.3% had HER2-positive cancers;13.4% had triplenegative cancers. The relative, cancer-specific, and diseasefree survival rates at 5 years were 84%, 85.2%, and 81.2%, respectively. Discussion. We performed the first comprehensive population-based breast cancer epidemiology study in Southern China using the Hong Kong Cancer Registry database. This provides a baseline study cohort for comparative studies with other Asian countries and Chinese who have migrated to the West. © The Author(s) 2011. This article is published with open access at Springerlink.com.published_or_final_versionSpringer Open Choice, 21 Feb 201

Novel App knock-in mouse model shows key features of amyloid pathology and reveals profound metabolic dysregulation of microglia.

BACKGROUND: Genetic mutations underlying familial Alzheimer\u27s disease (AD) were identified decades ago, but the field is still in search of transformative therapies for patients. While mouse models based on overexpression of mutated transgenes have yielded key insights in mechanisms of disease, those models are subject to artifacts, including random genetic integration of the transgene, ectopic expression and non-physiological protein levels. The genetic engineering of novel mouse models using knock-in approaches addresses some of those limitations. With mounting evidence of the role played by microglia in AD, high-dimensional approaches to phenotype microglia in those models are critical to refine our understanding of the immune response in the brain. METHODS: We engineered a novel App knock-in mouse model (App RESULTS: Leveraging multi-omics approaches, we discovered profound alteration of diverse lipids and metabolites as well as an exacerbated disease-associated transcriptomic response in microglia with high intracellular Aβ content. The App DISCUSSION: Our findings demonstrate that fibrillar Aβ in microglia is associated with lipid dyshomeostasis consistent with lysosomal dysfunction and foam cell phenotypes as well as profound immuno-metabolic perturbations, opening new avenues to further investigate metabolic pathways at play in microglia responding to AD-relevant pathogenesis. The in-depth characterization of pathological hallmarks of AD in this novel and open-access mouse model should serve as a resource for the scientific community to investigate disease-relevant biology

Progressive changes in somatosensory cortical maps in 2 week old kittens following low thoracic (T12) spinal cord transection

The present study investigated the reorganization of the somatosensory cortex in kittens following T12 spinal cord transection at 2 weeks of age. Multiunit electrophysiological methods were used to map the somatosensory cortex of kittens at 3, 6, and 9 weeks after the transection. The entire reorganized cortical region was driven by substitute cutaneous inputs at 3 weeks after spinal cord transection. This level of cortical responsiveness remained the same throughout the other two time periods studied. Also, throughout the 9 weeks studied, the majority of the substitute inputs came from the trunk. A smaller percentage of the substitute inputs arose from the shoulder girdle and the forelimb region. A lack of somatotopic and topographic order was seen in the reorganized cortex of all experimental animals. Finally, trunk receptive fields displayed a wide variety of shapes, sizes and orientations not seen in the normal cortex

The Range and Reproducibility of the Liver Frailty Index.

The Liver Frailty Index (LFI), composed of 3 performance-based tests (grip strength, chair stands, and balance), is a tool specifically developed in patients with cirrhosis to objectively measure physical function, a critical determinant of health outcomes. We aimed to (1) determine the range of LFI scores in adults with chronic liver disease but without cirrhosis, (2) determine the range of LFI scores in adults without known liver disease, and (3) evaluate reproducibility of the LFI in adults with cirrhosis listed for liver transplantation. Intraclass correlation coefficient (ICC) assessed interrater reliability of the LFI. Included were 91 adults with chronic liver disease, 109 adults without known liver disease, and 166 adults with cirrhosis with median Model for End-Stage Liver Disease-sodium of 16. Median (interquartile range) LFI was 3.6 (3.1-4.1) in adults with cirrhosis, 3.1 (2.5-3.7) in adults with chronic liver disease but not cirrhosis, and 2.7 (2.2-3.2) in adults without liver disease (P < 0.001). Using established LFI cutoffs for robust, prefrail, and frail categories, adults with cirrhosis or chronic liver disease were less likely to be robust (29% versus 53% versus 77%) and more likely to be prefrail (57% versus 42% versus 22%) or frail (14% versus 5% versus 1%) when compared with adults without liver disease (P < 0.001). The LFI had excellent reliability with ICC of 0.93 (95% confidence interval, 0.91-0.95). In conclusion, the LFI has external validity in noncirrhotic populations and is highly reproducible among different raters. This objective assessment tool can be implemented in outpatient clinical practice or research to operationalize the concept of physical frailty

Development and implementation of an electronic Clinical Dementia Rating and Financial Capacity Instrument‐Short Form

IntroductionTo address the need for remote assessments of cognitive decline and dementia, we developed and administered electronic versions of the Clinical Dementia Rating (CDR®) and the Financial Capacity Instrument-Short Form (FCI-SF) (F-CAP®), called the eCDR and eFCI, respectively.MethodsThe CDR and FCI-SF were adapted for remote, unsupervised, online use based on item response analysis of the standard instruments. Participants completed the eCDR and eFCI first in clinic, and then at home within 2 weeks.ResultsOf the 243 enrolled participants, 179 (73%) cognitively unimpaired (CU), 50 (21%) with mild cognitive impairment (MCI) or dementia, and 14 (6%) with an unknown diagnosis, 84% and 85% of them successfully completed the eCDR and eFCI, respectively, at home.DiscussionThese results show initial feasibility in developing and administering online instruments to remotely assess and monitor cognitive decline along the CU to MCI/very mild dementia continuum. Validation is an important next step

Novel App knock-in mouse model shows key features of amyloid pathology and reveals profound metabolic dysregulation of microglia.

BackgroundGenetic mutations underlying familial Alzheimer's disease (AD) were identified decades ago, but the field is still in search of transformative therapies for patients. While mouse models based on overexpression of mutated transgenes have yielded key insights in mechanisms of disease, those models are subject to artifacts, including random genetic integration of the transgene, ectopic expression and non-physiological protein levels. The genetic engineering of novel mouse models using knock-in approaches addresses some of those limitations. With mounting evidence of the role played by microglia in AD, high-dimensional approaches to phenotype microglia in those models are critical to refine our understanding of the immune response in the brain.MethodsWe engineered a novel App knock-in mouse model (AppSAA) using homologous recombination to introduce three disease-causing coding mutations (Swedish, Arctic and Austrian) to the mouse App gene. Amyloid-β pathology, neurodegeneration, glial responses, brain metabolism and behavioral phenotypes were characterized in heterozygous and homozygous AppSAA mice at different ages in brain and/ or biofluids. Wild type littermate mice were used as experimental controls. We used in situ imaging technologies to define the whole-brain distribution of amyloid plaques and compare it to other AD mouse models and human brain pathology. To further explore the microglial response to AD relevant pathology, we isolated microglia with fibrillar Aβ content from the brain and performed transcriptomics and metabolomics analyses and in vivo brain imaging to measure energy metabolism and microglial response. Finally, we also characterized the mice in various behavioral assays.ResultsLeveraging multi-omics approaches, we discovered profound alteration of diverse lipids and metabolites as well as an exacerbated disease-associated transcriptomic response in microglia with high intracellular Aβ content. The AppSAA knock-in mouse model recapitulates key pathological features of AD such as a progressive accumulation of parenchymal amyloid plaques and vascular amyloid deposits, altered astroglial and microglial responses and elevation of CSF markers of neurodegeneration. Those observations were associated with increased TSPO and FDG-PET brain signals and a hyperactivity phenotype as the animals aged.DiscussionOur findings demonstrate that fibrillar Aβ in microglia is associated with lipid dyshomeostasis consistent with lysosomal dysfunction and foam cell phenotypes as well as profound immuno-metabolic perturbations, opening new avenues to further investigate metabolic pathways at play in microglia responding to AD-relevant pathogenesis. The in-depth characterization of pathological hallmarks of AD in this novel and open-access mouse model should serve as a resource for the scientific community to investigate disease-relevant biology