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Dive into the research topics where Reza Shaker is active.

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Featured researches published by Reza Shaker.


The American Journal of Gastroenterology | 2003

Nighttime heartburn is an under-appreciated clinical problem that impacts sleep and daytime function: the results of a Gallup survey conducted on behalf of the American Gastroenterological Association

Reza Shaker; Donald O. Castell; Philip Schoenfeld; Stuart J. Spechler

OBJECTIVE:Although a large body of information exists about the prevalence of gastroesophageal reflux disease (GERD) in general, available data specifically addressing nocturnal reflux are limited. Because nocturnal acid reflux is reported to be associated with more severe injuries such as esophagitis and stricture, as well as adenocarcinoma of the esophagus, a better understanding of the prevalence and impact of nighttime heartburn as a sign of nocturnal acid reflux events can have significant potential management implications. The aims of this study were to determine the prevalence of nighttime heartburn and reflux-attributed supraesophageal symptoms among patients with GERD; and the impact of nighttime heartburn on sleep and several activities of daily living that could affect quality of life.METHODS:A nationwide telephone survey of 1000 adults experiencing heartburn at least once a week was conducted by the Gallup Organization on behalf of the American Gastroenterological Association.RESULTS:Altogether, 79% of respondents reported experiencing heartburn at night. Among those, 75% reported that symptoms affected their sleep, 63% believed that heartburn negatively affected their ability to sleep well, and 40% believed that nocturnal heartburn impaired their ability to function the following day. Of the 791 respondents with nighttime heartburn, 71% reported taking over-the-counter medicine for it, but only 29% of these rated this approach extremely effective. Forty-one percent reported trying prescription medicines, and 49% of these rated this approach extremely effective.CONCLUSIONS:Nighttime heartburn occurs in a large majority of adults with GERD, resulting in sleeping difficulties and impaired next-day function. The expected result from implemented therapy for heartburn is not achieved by a sizable percentage of patients.


Gastroenterology | 1988

Upper esophageal sphincter function during deglutition.

Peter J. Kahrilas; Wylie J. Dodds; Jerilyn A. Logemann; Reza Shaker

Upper esophageal sphincter function was investigated during swallows of graded volumes in 8 normal volunteers. Concurrent recordings of video-fluoroscopic and manometric studies were obtained and correlated with each other by means of a videotimer. Maximal upper esophageal sphincter (UES) pressure was typically located 1.5 cm distal to the air-tissue interface between the hypopharynx and the proximal margin of the sphincter. The region in which UES pressure was greater than or equal to 50% maximal averaged 1.0 cm in length. Thus, the physiologic high-pressure zone of the UES corresponds in size and location to that of the cricopharyngeus muscle. Fluoroscopic analysis of sphincter movement indicated that the sphincter high-pressure zone moved 2.0-2.5 cm orally during swallowing and that the magnitude of the orad movement was directly related to the volume of barium swallowed. The maximal anterior-posterior diameter of sphincter opening during a swallow ranged from 0.9 to 1.5 cm and was also directly related to the volume swallowed. The intervals of UES opening and relaxation increased significantly with increasing bolus volume; the duration of UES relaxation ranged from a mean of 0.37 s for dry swallows to 0.65 s for 20-ml swallows. Thus, the dynamics of UES function during deglutition are dependent upon the volume of the swallowed bolus. Larger bolus volumes are accommodated by both an increased diameter of sphincter opening and by prolongation of the interval of sphincter relaxation. Analysis of the timing of other reference points within the pharyngeal swallow sequence indicated that as the manometric interval of UES relaxation increased, the period of laryngeal elevation was prolonged, the UES relaxed earlier and contracted later, and the interval between the onset of laryngeal elevation and hypopharyngeal contraction increased.


Laryngoscope | 2006

Treatment of chronic posterior laryngitis with esomeprazole

Michael F. Vaezi; Joel E. Richter; C. Richard Stasney; Joseph R. Spiegel; Ralph A. Iannuzzi; Joseph A. Crawley; Clara Hwang; Mark Sostek; Reza Shaker

Objective: To evaluate the efficacy of acid‐suppressive therapy with the proton pump inhibitor esomeprazole on the signs and symptoms of chronic posterior laryngitis (CPL) in patients with suspected reflux laryngitis.


Gastrointestinal Endoscopy | 2004

Eosinophilic esophagitis in adults: an emerging problem with unique esophageal features

Jon W Potter; Kia Saeian; David Staff; Benson T. Massey; Richard A. Komorowski; Reza Shaker; Walter J. Hogan

BACKGROUND Eosinophilic esophagitis is an inflammatory condition in which there is dense eosinophilic infiltration of the surface lining of the esophagus. Reports of eosinophilic esophagitis pertain almost exclusively to pediatric populations. However, eosinophilic esophagitis is emerging as a clinical affliction of adults. This report describes the clinical and endoscopic findings of eosinophilic esophagitis in the largest cohort of adult patients reported to date. METHODS Twenty-nine patients (21 men, 8 women; mean age 35 years) with documented eosinophilic esophagitis (>/=15 eosinophils per high-power field in biopsy specimens) and a significant history of chronic dysphagia for solid food (24 patients) were evaluated clinically and endoscopically during a 3-year period (1999-2002). Fourteen patients (48%) had a history of asthma, environmental allergy, or atopy. In a subset of 15 patients, the diagnostic accuracy of endoscopy was compared with that of barium contrast esophagography. RESULTS Twenty-seven patients (93%) had abnormal endoscopic findings; 25 (86%) had unique esophageal structural changes, associated with a preserved mucosal surface, that were highly atypical for acid reflux injury. Structural alterations seen in adult patients with eosinophilic esophagitis may occur in combination or as a primary characteristic, e.g., uniform small-caliber esophagus, single or multiple corrugations (rings), proximal esophageal stenosis, or 1 to 2 mm whitish vesicles scattered over the mucosal surface. Barium contrast radiography combined with swallow of a barium-coated marshmallow identified 10 (67%) of the primary features observed endoscopically in 15 patients. However, radiography failed to detect other features noted at endoscopy (e.g., only 3/6 patients with proximal stenosis, 5/9 patients with concentric rings and none of 4 patients with small caliber esophagus). Eight of the 29 patients (20%) had a history of chronic heartburn. Twelve patients had been treated with a proton pump inhibitor and only 3 reported some improvement in the severity of dysphagia. CONCLUSIONS Relatively young age, a history of chronic dysphagia for solid food, and endoscopic detection of unique structural alterations atypical for GERD in an adult patient should prompt a suspicion of EE and subsequent biopsy confirmation. Acid reflux appears to have a secondary role in eosinophilic esophagitis. In an uncontrolled comparison, endoscopy was superior to barium contrast radiography for the diagnosis of eosinophilic esophagitis. The incidence of eosinophilic esophagitis in adults appears to be increasing.


Gastroenterology | 1995

Esophagopharyngeal Distribution of Refluxed Gastric Acid in Patients with Reflux Laryngitis.

Reza Shaker; Mary M. Milbrath; Junlong Ren; Robert J. Toohill; Walter J. Hogan; Qun Li; Candy Hofmann

BACKGROUND & AIMS A variety of otolaryngological abnormalities have been attributed to the contact of gastroesophageal refluxate with respective structures of the aerodigestive tract. The aim of this study was to determine and compare the pharyngoesophageal distribution of gastric acid refluxate between patients with proven laryngitis attributed clinically to gastroesophageal reflux and three control groups. METHODS An ambulatory 24-hour simultaneous three-site pharyngoesophageal pH monitoring technique was used to measure reflux parameters in the pharynx, proximal esophagus, and distal esophagus. RESULTS Between-group comparison showed no significant difference in the reflux parameters in the distal esophagus between the studied groups. A significantly higher percentage of distal reflux episodes reached the proximal esophagus in the laryngitis group than in the control groups (P < 0.01), and the number of pharyngeal reflux episodes and time of acid exposure were significantly higher in the laryngitis group than in the control groups (P < 0.001). CONCLUSIONS Compared with normal controls and patients with gastroesophageal reflux disease, pharyngeal reflux of gastric acid is significantly more prevalent and the ratio of proximal to distal esophageal acid reflux episodes is significantly increased in patients with posterior laryngitis. Simultaneous three-site ambulatory pharyngoesophageal pH monitoring may provide supporting evidence when the diagnosis of reflux-induced aerodigestive tract lesions is considered.


Human Brain Mapping | 1999

Event-related fMRI of tasks involving brief motion

Rasmus M. Birn; Peter A. Bandettini; Robert W. Cox; Reza Shaker

The assessment of brain function by blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) for tasks involving motion near the field of view is compromised by artifacts arising from the motion. The aim of this study is to demonstrate that these artifacts can be reduced by acquiring the average response from a brief stimulus (a “single‐trial,” or “event‐related,” paradigm) as opposed to alternating blocks of repeated task with rest (a “block‐trial” paradigm). The basis of this technique is that the NMR signal changes from neuronal activation are delayed relative to the motion due to a slow hemodynamic response. By acquiring the average response from a brief stimulus, motion‐induced signal changes occur prior to neuronal activation‐induced signal changes, and the two can thus be distinguished. This technique is applied to the tasks of speaking out loud, swallowing, jaw clenching, and tongue movement. Functional activation maps derived from the single‐trial paradigm contain significantly less artifact than functional activation maps derived from a more traditional block‐trial paradigm. Hum. Brain Mapping 7:106–114, 1999.


Dysphagia | 1989

Timing of Videofluoroscopic, Manometric Events, and Bolus Transit During the Oral and Pharyngeal Phases of Swallowing

Ian J. Cook; Wylie J. Dodds; Roberto Oliveira Dantas; Mark Kern; Benson T. Massey; Reza Shaker; Walter J. Hogan

The aims of this study were to evaluate and quantify the timing of events associated with the oral and pharyngeal phases of liquid swallows. For this purpose, we recorded 0–20 ml barium swallows in three groups of volunteers using videoradiographic, electromyographic, and manometric methods. The study findings indicated that a leading complex of tongue tip and tongue base movement as well as onset of superior hyoid movement and mylohyoid myoelectric activity occurred in a tight temporal relationship at the inception of swallowing. Two distinct general types of normal swallows were observed. The common “incisor-type” swallow began with the bolus positioned on the tongue with the tongue tip pressed against the upper incisors and maxillary alveolar ridge. At the onset of the “dipper-type” swallow the bolus was located beneath the anterior tongue and the tongue tip scooped the bolus to a supralingual location. Beginning with tongue-tip peristaltic movement at the upper incisors, the two swallow types were identical. Swallow events that occurred after lingual peristaltic movement at the maxillary incisors showed a volume-dependent forward migration in time that led to earlier movement of the hyoid and larynx as well as earlier opening of the upper esophageal sphincter in order to receive the large boluses that arrived sooner in the pharynx during the swallow sequence than did smaller boluses. The study findings indicated that timing of swallow events should be considered in reference to both swallow type and bolus volume. The findings also indicated an important distinction between peristaltic transit and bolus clearance.


Gastroenterology | 1990

Coordination of deglutitive glottic closure with oropharyngeal swallowing

Reza Shaker; Wylie J. Dodds; Roberto Oliveira Dantas; Walter J. Hogan; Ronald C. Arndorfer

The goals of this study were to quantify the temporal relationship between swallow-induced glottic closure and (a) signals of swallow initiation, such as hyoid bone movement, tongue base movement, and mylohyoid electrical activity; (b) pharyngeal peristalsis; (c) laryngeal elevation; (d) vestibular closure; and (e) oropharyngeal barium bolus transit. Eight normal subjects (age 20-30 yr) were studied by concurrent transnasal video laryngoscopy, pharyngeal intraluminal manometry, and submental surface electromyography. The manometric, electromyographic, and both video recordings were synchronized with one another using a specially designed event marker. Dry, 5-ml water, and 5-ml barium swallows were recorded. Frame-by-frame analysis of the video endoscopic recordings showed that deglutitive laryngeal kinetics consisted of vocal cord adduction associated with transverse approximation of the arytenoids followed by vertical approximation of arytenoids to the base of the epiglottis followed by laryngeal ascent and epiglottic descent. Onset of swallow-induced vocal cord adduction preceded the onset of hyoid bone movement, base of the tongue movement, and submental surface myoelectric activity by 0.33 +/- 0.04 (SE) s, 0.31 +/- 0.04 s, and 0.38 +/- 0.04 s, respectively. Onset of vocal cord adduction also preceded the initiation of peristalsis in the nasopharynx and its propagation to oropharynx and upper esophageal sphincter by 0.64 +/- 0.05 s, 0.82 +/- 0.05 s, and 1.08 +/- 0.04 s, respectively. The time between the onset of vocal cord adduction and their return to full opening was 2.2 +/- 0.09 s. It was concluded that (a) among events evaluated, vocal cord adduction is the initial event during the swallowing sequence; (b) laryngeal kinetics during deglutition have distinctive features, and their close coordination with other swallowing events suggests that they are an essential feature of the swallowing program; and (c) abnormal laryngeal kinetics or lack of coordination between the glottic closure mechanism and oropharyngeal bolus transport may have an important role in swallow-induced aspiration.


The American Journal of Gastroenterology | 2004

Physical and pH properties of gastroesophagopharyngeal refluxate: a 24-hour simultaneous ambulatory impedance and pH monitoring study.

Osamu Kawamura; Muhammad Aslam; Tanya Rittmann; Candy Hofmann; Reza Shaker

OBJECTIVES:Frequency occurrence of nonacidic and nonliquid reflux events in the pharynx has not been systematically studied. The aim of the present study was to characterize the physical (liquid, gas, and mixed gas/liquid) and pH properties of the gastroesophagopharyngeal refluxate.METHODS:We performed a total of 31 24-h simultaneous ambulatory pharyngoesophageal impedance and pH recordings in 11 GERD patients, 10 patients with reflux-attributed laryngitis, and 10 healthy controls.RESULTS:On average, the total number of reflux events (all kinds) in the pharynx was less than half of that in the proximal esophagus (18 ± 4 vs 50 ± 4, p < 0.01). Most of the pharyngeal reflux events were gas events and were observed in all three studied groups. Prevalence of these gas reflux events ranged between 0 and 74. The number of gas reflux events accompanied by a minor pH drop in laryngitis patients (1 (0–36)) was significantly higher than those in GERD and controls (0 (0–2) and 0 (0–1), respectively, p < 0.05). There was no significant difference in the number of nonacidic gas reflux events among the three groups (GERD: 10 (2–57), laryngitis: 11.5 (0–51), controls: 10.5 (0–27)). Impedance recording identified a total number of 566 events in the pharynx. Of these, a total of 563 events were compatible with gas reflux events, 101 events were accompanied by minor drops in intrapharyngeal pH, whereas 460 events were not accompanied by any pharyngeal pH change.CONCLUSIONS:Concurrent impedance and pH recordings detect significantly more events qualifying as reflux in the pharynx than pH recordings alone. A substantial majority of these events are gaseous refluxes both with and without minor pH drops. Gas reflux events with weak acidity appear to be more common among patients with reflux-attributed laryngeal lesions compared to GERD patients and controls.


Dysphagia | 1988

Pressure-flow dynamics of the oral phase of swallowing

Reza Shaker; Ian J. Cook; Wylie J. Dodds; Walter J. Hogan

In 5 healthy volunteers, we studied the pressure-flow kinetics of the oral phase of swallowing. The regional profile within the oral cavity during swallowing was recorded, at the tongue tip (T1), dorsum of the tongue (T2), 3 cm from the tongue tip, oral floor, buccal cavity, and between the lips during swallows of water (0–20 ml) and 5 ml of mashed potato. Two strain gauge (SG) probes, each with two transducer recording sites 3 cm apart, were used for recording pressure. Supralingual and sublingual pressure were recorded concurrently. The relationship between transit of a barium bolus and deglutitive oral pressure phenomena was determined by concurrent videoradiography and manometry. Lingual pressure with the SG facing the tongue showed the most consistent recording and highest pressure: 193±16 (SE) mmHg at T1 and 214±18 mmHg at T2 for dry swallows. Pressures were similar for water swallows. However, mashed potato swallows produced a pressure of 383±30 mmHg at T1 and 485±52 mmHg at T2 that were greater than for water swallows (p<0.01). Pressure recorded with the transducers facing the hard palate and, to a lesser extent, laterally, was low and inconsistent. Oral-floor pressure was greatest with the transducers oriented upwards and averaged 64±2.9 mmHg proximally and 173±36 mmHg distally. At all sites the pressure waves propagated sequentially, toward the pharynx. Minimal pressure increases occurred in the buccal cavity. Lip squeeze varied from 0 to 90 mmHg.We can draw the following conclusions. The oral phase of swallowing includes contraction of the oral floor, which provides a platform for tongue movement. Oral pressure waves propagate toward the pharynx so that a swallowed bolus is propelled ahead of the point of lingual-palatal closure. Lingual peristalsis exhibits a wide range of pressures, with lower pressure for dry and liquid boluses than for a semisolid bolus. Buccal and lip contractions act as stabilizing forces, but do not contribute to bolus propulsion. Significant differences exist in the radial pressure profile of lingual peristalsis, with maximal pressure oriented toward the tongue.

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Mark Kern

Medical College of Wisconsin

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Bidyut K. Medda

Medical College of Wisconsin

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Ivan M. Lang

Medical College of Wisconsin

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Arash Babaei

Medical College of Wisconsin

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Walter J. Hogan

Medical College of Wisconsin

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Kulwinder S. Dua

Medical College of Wisconsin

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Patrick Sanvanson

Medical College of Wisconsin

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Jyoti N. Sengupta

Medical College of Wisconsin

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Ling Mei

Cedars-Sinai Medical Center

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