99 research outputs found

    Genetic and temporal aspects of protection by kanamycin against cochlear noise injury

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    Experiments explored the minimal kanamycin dosing regimen that renders protection against noise induced hearing loss in young CBA/J mice. We also tested the age-dependence of protection in CBA/J as well as the dependence of protection on a particular genetic background in experiments using young C57BL/6J and CBA/CaJ mice

    Ethical Considerations for Neuropsychologists as Functional Magnetic Imagers

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    This discussion highlights ethical and practical issues potential neuropsychologist-imagers should consider in conducting functional magnetic resonance imaging (fMRI). While fMRI is not currently approved for clinical use, research is ongoing which has implications for clinical practice, from refining brain–behavior relationships, to assisting with diagnosis and treatment decisions. To protect the welfare of cognitively impaired populations requires special care with respect to MR risks and informed consent. Competent functional imaging requires an understanding of the strengths, limitations, and appropriate domain of applications of the measure

    PS76. Memory Decline following Carotid Interventions

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    Patient characteristics can influence the incidence of perioperative microemboli during carotid artery interventions

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    Purpose. Perioperative cerebral microembolization demonstrated on diffusion-weighted MRI (DWI) can occur following carotid endarterectomy (CEA) and carotid artery stenting (CAS). We sought to explore potential risk factors for this in the large patient cohort. Methods. We reviewed a 6-year consecutive patient cohort that received either CEA or CAS, and perioperative DWI evaluations. Results. 303 patients were reviewed, and 56 (19.4%) patients were found to have perioperative microemboli. The incidence was higher among patients who received CAS (P &lt; 0.001). Hypertension (P = 0.03), smoking (P = 0.001), and a history of transient ischemic attacks (P = 0.04) were risk factors for microembolization. The risk was higher among CEA patients with obesity (P = 0.05), and among CAS patients with coronary artery disease (P = 0.03). Conclusion. Specific patient populations are likely more prone to develop perioperative cerebral microemboli following carotid intervention. Continued risk stratification may help decrease future perioperative cerebral microembolization rates.</jats:p

    Physiological constraints and energetic costs of diving behaviour in marine mammals : a review of studies using trained Steller sea lions diving in the open ocean

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    The research was funded through a number of sources, including grants provided by the Natural Sciences and Engineering Research Council (Canada) and from the US National Oceanic and Atmospheric Administration to the North Pacific Universities Marine Mammal Research Consortium through the North Pacific Marine Science Foundation.Marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.PostprintPeer reviewe

    Raloxifene for women with Alzheimer disease: A randomized controlled pilot trial

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    OBJECTIVE: To determine whether raloxifene, a selective estrogen receptor modulator, improves cognitive function compared with placebo in women with Alzheimer disease (AD) and to provide an estimate of cognitive effect. METHODS: This pilot study was conducted as a randomized, double-blind, placebo-controlled trial, with a planned treatment of 12 months. Women with late-onset AD of mild to moderate severity were randomly allocated to high-dose (120 mg) oral raloxifene or identical placebo provided once daily. The primary outcome compared between treatment groups at 12 months was change in the Alzheimer's Disease Assessment Scale, cognitive subscale (ADAS-cog). RESULTS: Forty-two women randomized to raloxifene or placebo were included in intent-to-treat analyses (mean age 76 years, range 68-84), and 39 women contributed 12-month outcomes. ADAS-cog change scores at 12 months did not differ significantly between treatment groups (standardized difference 0.03, 95% confidence interval -0.39 to 0.44, 2-tailed p = 0.89). Raloxifene and placebo groups did not differ significantly on secondary analyses of dementia rating, activities of daily living, behavior, or a global cognition composite score. Caregiver burden and caregiver distress were similar in both groups. CONCLUSIONS: Results on the primary outcome showed no cognitive benefits in the raloxifene-treated group. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for women with AD, raloxifene does not have a significant cognitive effect. The study lacked the precision to exclude a small effect

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
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