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Metropolitan Government of Nashville-Davidson (balance), TN, United States

McGrane S.,Vanderbilt University | Atria N.P.,Critical Care | Barwise J.A.,Tennessee Valley Healthcare System
Current Opinion in Anaesthesiology

Purpose of Review: The autonomic nervous system functions to control heart rate, blood pressure, respiratory rate, gastrointestinal motility, hormone release, and body temperature on a second-to-second basis. Here we summarize some of the latest literature on autonomic dysfunction, focusing primarily on the perioperative implications. RECENT FINDINGS: The variety of autonomic dysfunction now extends to a large number of clinical conditions in which the cause or effect of the autonomic component is blurred. Methods for detecting dysautonomia can be as simple as performing a history and physical examination that includes orthostatic vital signs measured in both recumbent and vertical positions; however, specialized laboratories are required for definitive diagnosis. Heart rate variability monitoring is becoming more commonplace in the assessment and understanding of autonomic instability. Degenerative diseases of the autonomic nervous system include ParkinsonÊs disease and multiple system atrophy, with the most serious manifestations being postural hypotension and paradoxical supine hypertension. Other conditions occur in which the autonomic dysfunction is only part of a larger disease process, such as diabetic autonomic neuropathy, traumatic brain injury, and spinal cord injury. SUMMARY: Patients with dysautonomia often have unpredictable and paradoxical physiological responses to various perioperative stimuli. Knowledge of the underlying pathophysiology of their condition is required in order to reduce symptom exacerbation and limit morbidity and mortality during the perioperative period. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Pasek R.C.,Vanderbilt University | Gannon M.,Tennessee Valley Healthcare System | Gannon M.,Vanderbilt University
American Journal of Physiology - Endocrinology and Metabolism

The maintenance of glucose homeostasis during pregnancy is critical to the health and well-being of both the mother and the developing fetus. Strikingly, approximately 7% of human pregnancies are characterized by insufficient insulin production or signaling, resulting in gestational diabetes mellitus (GDM). In addition to the acute health concerns of hyperglycemia, women diagnosed with GDM during pregnancy have an increased incidence of complications during pregnancy as well as an increased risk of developing type 2 diabetes (T2D) later in life. Furthermore, children born to mothers diagnosed with GDM have increased incidence of perinatal complications, including hypoglycemia, respiratory distress syndrome, and macrosomia, as well as an increased risk of being obese or developing T2D as adults. No single environmental or genetic factor is solely responsible for the disease; instead, a variety of risk factors, including weight, ethnicity, genetics, and family history, contribute to the likelihood of developing GDM, making the generation of animal models that fully recapitulate the disease difficult. Here, we discuss and critique the various animal models that have been generated to better understand the etiology of diabetes during pregnancy and its physiological impacts on both the mother and the fetus. Strategies utilized are diverse in nature and include the use of surgical manipulation, pharmacological treatment, nutritional manipulation, and genetic approaches in a variety of animal models. Continued development of animal models of GDM is essential for understanding the consequences of this disease as well as providing insights into potential treatments and preventative measures. © 2013 the American Physiological Society. Source

Pendergast J.S.,Vanderbilt University | Niswender K.D.,Tennessee Valley Healthcare System | Niswender K.D.,Vanderbilt University | Yamazaki S.,Vanderbilt University

The mammalian circadian system is composed of multiple central and peripheral clocks that are temporally coordinated to synchronize physiology and behavior with environmental cycles. Mammals have three homologs of the circadian Period gene (Per1, 2, 3). While numerous studies have demonstrated that Per1 and Per2 are necessary for molecular timekeeping and light responsiveness in the master circadian clock in the suprachiasmatic nuclei (SCN), the function of Per3 has been elusive. In the current study, we investigated the role of Per3 in circadian timekeeping in central and peripheral oscillators by analyzing PER2::LUCIFERASE expression in tissues explanted from C57BL/6J wild-type and Per3-/- mice. We observed shortening of the periods in some tissues from Per3-/- mice compared to wild-types. Importantly, the periods were not altered in other tissues, including the SCN, in Per3-/- mice. We also found that Per3-dependent shortening of endogenous periods resulted in advanced phases of those tissues, demonstrating that the in vitro phenotype is also present in vivo. Our data demonstrate that Per3 is important for endogenous timekeeping in specific tissues and those tissue-specific changes in endogenous periods result in internal misalignment of circadian clocks in Per3-/- mice. Taken together, our studies demonstrate that Per3 is a key player in the mammalian circadian system. Source

Randall M.J.,Tennessee Valley Healthcare System
Military Medicine

This study examined the effectiveness of Public Law 110-181, "National Defense Authorization Act of Fiscal Year 2008, Title XVI-Wounded Warriors Matter," as it relates to health care for returning Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) combat veterans. Specifically, it examined the gap between the time an OEF/OIF combat service member left active service and subsequently obtained health care within the Veteran Affairs (VA) Healthcare System, and which factors influenced or impeded the veteran from obtaining health care sooner. Data were collected from 376 OEF/OIF combat veterans who sought health care at the Nashville or Murfreesboro VA Medical Centers. A questionnaire was designed exclusively for this study. The average time gap for an OEF/OIF combat veteran to transition from Department of Defense to VA health care was 3.83 months (SD 7.17). Twenty-six percent of respondents reported there were factors that impeded them from coming to the VA sooner. Factors included lack of knowledge about VA benefits, transportation/distance, perceptions of losing military career, seeking help as sign of weakness, and VA reputation. The study provided some evidence to support that Department of Defense and VA are meeting mandates for providing seamless transition of health care set forth by "Public Law 110-181, National Defense Authorization Act of Fiscal Year 2008". © Association of Military Surgeons of the U.S. All rights reserved. Source

The current study attempted to improve upon the efficiency and accuracy of one of the most frequently administered measures of test validity, the Test of Memory Malingering (TOMM) by utilizing two short forms (TOMM trial 1 or TOMM1; and errors on the first 10 items of TOMM1 or TOMMe10). In addition, we cross-validated the accuracy of five embedded measures frequently used in malingering research. TOMM1 and TOMMe10 were highly accurate in predicting test validity (area under the curve [AUC] = 92% and 87%, respectively; TOMM1 ≤40 and TOMMe10 ≥1; sensitivities >70% and specificities .90%). A logistic regression of five embedded measures showed better accuracy compared with any individual embedded measure alone or in combination (AUC = 87%). TOMM1 and TOMMe10 provide evidence of greater sensitivity to invalid test performance compared with the standard TOMM administration and the use of regression improved the accuracy of the five embedded cognitive measures. © The Author 2012. Published by Oxford University Press. All rights reserved. Source

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