3551 Roger Brooke Drive Brooke Army Medical Ctr -Dept Of Medicine/Cardiology
Ft Sam Houston TX 78234
Medical School: Other - Unknown
Accepts Medicare: No
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License #: 0101240353
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Electrochemical camera chip for simultaneous imaging of multiple metabolites in biofilms. - Nature communications
Monitoring spatial distribution of metabolites in multicellular structures can enhance understanding of the biochemical processes and regulation involved in cellular community development. Here we report on an electrochemical camera chip capable of simultaneous spatial imaging of multiple redox-active phenazine metabolites produced by Pseudomonas aeruginosa PA14 colony biofilms. The chip features an 8 mm Ã— 8 mm array of 1,824 electrodes multiplexed to 38 parallel output channels. Using this chip, we demonstrate potential-sweep-based electrochemical imaging of whole-biofilms at measurement rates in excess of 0.2 s per electrode. Analysis of mutants with various capacities for phenazine production reveals distribution of phenazine-1-carboxylic acid (PCA) throughout the colony, with 5-methylphenazine-1-carboxylic acid (5-MCA) and pyocyanin (PYO) localized to the colony edge. Anaerobic growth on nitrate confirms the O2-dependence of PYO production and indicates an effect of O2 availability on 5-MCA synthesis. This integrated-circuit-based technique promises wide applicability in detecting redox-active species from diverse biological samples.
Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms. - Nature communications
Despite advances in monitoring spatiotemporal expression patterns of genes and proteins with fluorescent probes, direct detection of metabolites and small molecules remains challenging. A technique for spatially resolved detection of small molecules would benefit the study of redox-active metabolites that are produced by microbial biofilms and can affect their development. Here we present an integrated circuit-based electrochemical sensing platform featuring an array of working electrodes and parallel potentiostat channels. 'Images' over a 3.25 Ã— 0.9â€‰mm(2) area can be captured with a diffusion-limited spatial resolution of 750â€‰Î¼m. We demonstrate that square wave voltammetry can be used to detect, identify and quantify (for concentrations as low as 2.6â€‰Î¼M) four distinct redox-active metabolites called phenazines. We characterize phenazine production in both wild-type and mutant Pseudomonas aeruginosa PA14 colony biofilms, and find correlations with fluorescent reporter imaging of phenazine biosynthetic gene expression.
Cardiac electrophysiology and the athlete: a primer for the sports clinician. - Current sports medicine reports
Intense exercise requires a significant increase in cardiac output in order to meet the needs of the skeletal muscles for oxygenated blood. In order to improve cardiac performance, the autonomic nervous system increases sympathetic tone primarily through release of norepinephrine from postganglionic receptors to stimulate the Î²-adrenergic receptors of the nodal and muscle tissue of the heart. This event initiates a signaling cascade focused on increasing the amount of calcium available to the contractile myofilaments in the cardiac cell. Failure of the myocytes to counterbalance the increase in inward ion flow or adequately sequester cytosolic calcium during diastole leads to potentially catastrophic electrical instability. In this review, the relationship between the cellular events initiated by exercise and the induction of arrhythmias associated with the long QT, Brugada, and Wolff-Parkinson-White syndromes; catecholaminergic polymorphic ventricular tachycardia; and the heritable cardiomyopathies are explored.
Correlations between local strains and tissue phenotypes in an experimental model of skeletal healing. - Journal of biomechanics
Defining how mechanical cues regulate tissue differentiation during skeletal healing can benefit treatment of orthopaedic injuries and may also provide insight into the influence of the mechanical environment on skeletal development. Different global (i.e., organ-level) mechanical loads applied to bone fractures or osteotomies are known to result in different healing outcomes. However, the local stimuli that promote formation of different skeletal tissues have yet to be established. Finite element analyses can estimate local stresses and strains but require many assumptions regarding tissue material properties and boundary conditions. This study used an experimental approach to investigate relationships between the strains experienced by tissues in a mechanically stimulated osteotomy gap and the patterns of tissue differentiation that occur during healing. Strains induced by the applied, global mechanical loads were quantified on the mid-sagittal plane of the callus using digital image correlation. Strain fields were then compared to the distribution of tissue phenotypes, as quantified by histomorphometry, using logistic regression. Significant and consistent associations were found between the strains experienced by a region of the callus and the tissue type present in that region. Specifically, the probability of encountering cartilage increased, and that of encountering woven bone decreased, with increasing octahedral shear strain and, to a lesser extent, maximum principal strain. Volumetric strain was the least consistent predictor of tissue type, although towards the end of the four-week stimulation timecourse, cartilage was associated with increasingly negative volumetric strains. These results indicate that shear strain may be an important regulator of tissue fate during skeletal healing.2010 Elsevier Ltd. All rights reserved.
Constrictive pericarditis: a cause of exertion-induced dyspnea in a soldier with a prior sternotomy. - Military medicine
Diagnosing the underlying etiology of dyspnea on exertion in adults can be challenging, often requiring the clinician to distinguish cardiac or pulmonary pathological conditions from metabolic, neurological, or hematological conditions or from chest wall abnormalities. We report such a case involving a 29-year-old, male, active duty Army soldier. With a history of a median sternotomy, symptoms of right- and left-side heart failure, and examination findings suggesting elevated right atrial pressure, pericardial disease was pursued. Echocardiography and cardiac catheterization revealed constrictive physiological features, namely, elevation and near-equalization of right- and left-side pressures and ventricular interdependence, whereas computed tomography illustrated pericardial thickening, ultimately leading to the diagnosis of constrictive pericarditis. The patient was treated with a complete pericardiectomy, leading to symptom resolution and improved exercise capacity. This case report of a rare condition offers a concise etiological and physiological overview of constrictive pericarditis and demonstrates an effective multimodal diagnostic approach. The scientific evidence provided may assist general practitioners in making decisions to differentiate this clinical condition from similar cardiac or cardiopulmonary conditions.
Jugular venous pulse: window into the right heart. - Southern medical journal
Although physicians began associating conspicuous neck veins with heart disease almost three centuries ago, the jugular venous pulse remains an often ignored component of the physical examination. Many physicians have not invested in the necessary understanding of the technique, and there is a misconception that its examination is difficult and of limited clinical value. When performed properly, evaluation of the jugular venous pulse can be extremely useful in distinguishing the cause of dyspnea and edema. The normal jugular venous pulse is reviewed, and pulse wave abnormalities are described, including ways in which they can provide clues to the diagnosis of certain disease states, ranging from pericardial disease to conduction disturbances. The jugular venous pulse provides a window into the right heart and an occasional glimpse of left heart hemodynamics. By peering through this window, clinicians can gain valuable information in the diagnostic evaluation of the cardiovascular patient.
Physical activity patterns and exercise performance in cardiac transplant recipients. - Journal of cardiopulmonary rehabilitation
Cardiac transplantation (CTX) improves exercise tolerance, but CTX recipients still achieve only 50% to 70% of normal values for exercise capacity. Among the factors suggested to explain the reduced exercise tolerance in CTX recipients is deconditioning. Little is known about the relation between physical activity patterns and exercise test responses in CTX patients.Forty-seven CTX patients (mean age 47 +/- 12 years; mean 4.8 +/- 3.0 years after CTX) underwent maximal exercise testing and assessment of current and past physical activity patterns using a questionnaire. Energy expenditure from recreational and occupational activities over the last year and for adulthood were expressed in kcal/week and correlated with peak oxygen consumption (VO(2)), VO(2) at the ventilatory threshold, and the percentage of age-predicted peak VO(2) achieved.The patients reported expending a mean of approximately 1100 kcal/week in recreational activity, suggesting a moderate level of physical activity is maintained after CTX. The mean peak VO(2) achieved for the group was 17.2 +/- 5.2 mL/kg/min, corresponding to 59% +/- 14% of age-predicted exercise capacity. Significant but modest associations were observed between recreational energy expenditure during the last year and percentage of age-predicted peak VO(2) achieved (r = 0.34, P <.01), and VO(2) at the ventilatory threshold (r = 0.45, P <.01). Energy expenditure from blocks walked and stairs climbed per week was modestly associated with peak VO(2) (r = 0.36, P <.05), percentage of predicted peak VO(2) achieved (r = 0.39, P <.01), and VO(2) at the ventilatory threshold (r = 0.42, P <.01). Exercise capacity was poorly related to occupational and recreational activities when expressed as average weekly energy expended throughout adulthood.Post-CTX patients maintain a moderately active lifestyle. Measures of exercise tolerance generally are related to recent daily recreational activities in CTX patients, but these associations are modest. The many physiologic factors unique to CTX recipients likely play a more important role than deconditioning in determining exercise tolerance in these patients.
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3551 Roger Brooke Drive Brooke Army Medical Ctr -Dept Of Medicine/Cardiology Ft Sam Houston, TX 78234
3551 Roger Brooke Dr Saushec Emergency Medicine Residency
Jbsa Ft Sam Houston, TX 78234
3551 Roger Brooke Dr Brooke Army Medical Center
2410 Stanley Road Dentac Suite 200J
2410 Stanley Rd Dentac Suite 200J
Brooke Army Medical Ctr 3851 Roger Brooke Drive
3851 Roger Brooke Dr Mche-Qd (Creds)
3551 Roger Brooke Dr
2018 Army Blvd., Apt A Usa Dental Activity
Ft Sam Houston, TX 78234