Anatomy, physiology and pathophysiology of dysphagia.
ABSTRACT This is a review paper examining the pathogenesis of oropharyngeal dysphagia. Pharyngeal anatomy and physiology are discussed along with a detailed description of the neuronal architecture and function of the medullary swallowing center. The oropharyngeal swallow is then examined in biomechanical terms emphasizing that the swallow is comprised of several elements (velopharyngeal closure, upper esophageal sphincter opening, closure of the laryngeal vestibule, tongue loading, tongue pulsion and pharyngeal clearance) each of which can be compromised, causing dysphagia. The key modality for evaluating patients with oropharyngeal dysphagia is the videofluoroscopic swallowing study which is analyzed according to the efficacy with which these functional elements of the swallow are accomplished. Specific therapy can then be addressed toward correcting dysfunctional elements.
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ABSTRACT: Carbohydrates are used extensively in the pharmaceutical sector as excipients to facilitate packaging and delivery of drugs. These formats include tablets, capsules, liquids, suspensions, gels, inhalation products and strips. Apart from being very diverse in structure and properties, carbohydrates benefit from a safe history of usage with a positive health profile. These incorporate a number of starch derivatives. Dextrins represent hydrolysis products of starches and are thus α-glucans with both α-(1,4) and α-(1,6) bonds. They are used in different formats in pharmaceutical systems, and provide a number of technical advantages over other materials. This short review focuses on the use of carbohydrates and especially dextrins as oral delivery vehicles and their associated functionality and properties in these systems.Starch - Starke 07/2011; 63(7):424 - 431. DOI:10.1002/star.201000110 · 1.40 Impact Factor
La radiologia medica 09/2008; 113(6):923-940. · 1.37 Impact Factor
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ABSTRACT: Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, which is modeled as an actively contracting, fiber-reinforced tube. A simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are then extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation into an integrated model. Consistent with experimental observations, our simulations capture the pressure peak generated by the muscle activation pulse that travels along the bolus tail. These fully resolved simulations provide new insights into roles of the mucosal layers during bolus transport. In addition, the information on pressure and the kinematics of the esophageal wall due to the coordination of muscle activation is provided, which may help relate clinical data from manometry and ultrasound images to the underlying esophageal motor function.