Mayo Clinic proceedings
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Obstructive sleep apnea (OSA) is a common medical condition that occurs in approximately 5% to 15% of the population. The pathophysiology of OSA is characterized by repetitive occlusions of the posterior pharynx during sleep that obstruct the airway, followed by oxyhemoglobin desaturation, persistent inspiratory efforts against the occluded airway, and termination by arousal from sleep. Obstructive sleep apnea is associated with daytime sleepiness and fatigue, likely due to fragmented sleep from recurrent arousals. ⋯ Obstructive sleep apnea has been associated with enhanced platelet activity and aggregation. Leukocyte adhesion and accumulation on endothelial cells are common in both OSA and atherosclerosis. Clinicians should be aware that OSA may be a risk factor for the development of cardiovascular disease.
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Mayo Clinic proceedings · Jul 2004
ReviewEvaluation and management of asymptomatic carotid artery stenosis.
Internal carotid artery stenosis (ICAS) is responsible for approximately 30% of ischemic strokes. Internal carotid artery stenosis of greater than 50% is present in about 4% to 8% of the population aged 50 to 79 years. Natural history studies and clinical trials have shown a small increase in stroke risk in patients with increasing degrees of ICAS, especially in those with greater than 80% reduction in carotid artery diameter. ⋯ Clinicians continue to struggle with treatment decisions for patients with asymptomatic ICAS. Carotid endarterectomy for asymptomatic ICAS should be considered only for medically stable patients with 80% or greater stenosis who are expected to live at least 5 years, and only in centers with surgeons who have a demonstrated low (<3%) perioperative complication rate. We outline the prevalence and natural history of ICAS, the evidence for CEA in patients with asymptomatic ICAS, the roles of screening and monitoring for ICAS, the methods of evaluating ICAS, and the implications for practicing clinicians.
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Mayo Clinic proceedings · May 2004
Review Case ReportsEpidural abscess and meningitis after epidural corticosteroid injection.
Epidural abscess with and without associated meningitis after epidural corticosteroid injections for radicular back pain is a rarely reported complication. We report the occurrence of an epidural abscess and meningitis in a 70-year-old man after 2 epidural corticosteroid injections for treatment of acute radicular lumbar back pain. At the time of diagnosis, cerebrospinal fluid cultures grew Staphylococcus aureus, and the patient was treated with intravenous antibiotics. ⋯ A literature search identified 11 reported cases of epidural abscess, 2 of epidural abscess and meningitis, and 1 of meningitis attributed to epidural corticosteroid injections. Eight of the 14 reported patients were immunocompromised, and 8 (67%) of the 12 in whom cultures of blood, cerebrospinal fluid, or epidural pus were performed had results positive for S. aureus. Antibiotic prophylaxis for S. aureus should be considered for immunocompromised patients undergoing epidural corticosteroid injections.
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Mayo Clinic proceedings · May 2004
ReviewPrimer on medical genomics. Part XIV: Introduction to systems biology--a new approach to understanding disease and treatment.
The advent of the "-omics revolution" has forced us to reevaluate our ability to acquire, measure, and handle large data sets. Omic platforms such as expression arrays and mass spectrometry, with their exquisite selectivity, sensitivity, and specificity, are unrivaled technologies for detection, quantitation, and identification of DNA, messenger RNA, proteins, and metabolites derived from complex body tissue and fluids. More recently, attempts have been made to capture the utility of these platform technologies and combine them under the umbrella of systems biology, also referred to as pathway, network, or integrative biology. ⋯ Ultimately, this requires a perspective on how complex systems behave and are modulated. In this regard, systems biology, more appropriately considered as a process containing a series of modules, aims to provide tools and capabilities to carry out such tasks. We describe the essentials required to carry out systems biology experiments, the method in which integrated data in the form of a systems biology correlation network affords new insight into understanding disease, and the vista of developing more efficient biomarkers and therapeutic agents.