The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

Reza Shaker - One of the best experts on this subject based on the ideXlab platform.

  • mechanisms of reflexes induced by esophageal distension
    American Journal of Physiology-gastrointestinal and Liver Physiology, 2001
    Co-Authors: Ivan M Lang, Bidyut K Medda, Reza Shaker
    Abstract:

    We investigated the mechanisms of esophageal distension-induced reflexes in decerebrate cats. Slow air esophageal distension activated esophago-upper esophageal sphincter (UES) contractile reflex (EUCR) and secondary peristalsis (2P). Rapid air distension activated esophago-UES relaxation reflex (EURR), esophago-glottal closure reflex (EGCR), esophago-hyoid distraction reflex (EHDR), and esophago-esophagus contraction reflex (EECR). Longitudinal esophageal stretch did not activate these reflexes. Magnitude and timing of EUCR were related to 2P but not injected air volume. Cervical esophagus transection did not affect the threshold of any reflex. Bolus diversion prevented swallow-related esophageal peristalsis. Lidocaine or capsaicin esophageal perfusion, esophageal mucosal layer removal, or intravenous baclofen blocked or inhibited EURR, EGCR, EHDR, and EECR but not EUCR or 2P. Thoracic vagotomy blocked all reflexes. These six reflexes can be activated by esophageal distension, and they occur in two sets depending on inflation rate rather than volume. EUCR was independent of 2P, but 2P activated EUCR; therefore, EUCR may help prevent reflux during peristalsis. All esophageal peristalsis may be secondary to esophageal stimulation in the cat. EURR, EHDR, EGCR, and EECR may contribute to belching and are probably mediated by capsaicin-sensitive, rapidly adapting mucosal mechanoreceptors. GABA-B receptors also inhibit these reflexes. EUCR and 2P are probably mediated by slowly adapting muscular mechanoreceptors. All six reflexes are mediated by vagal afferent fibers.

  • Pharyngo‐UES contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.

  • pharyngo ues contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.

Thomas Carlstedt - One of the best experts on this subject based on the ideXlab platform.

  • return of spinal reflex after spinal cord surgery for brachial plexus avulsion injury
    Journal of Neurosurgery, 2012
    Co-Authors: Thomas Carlstedt, Peter V Misra, Anastasia Papadaki, Donald Mcrobbie, P Anand
    Abstract:

    Motor but not sensory function has been described after spinal cord surgery in patients with brachial plexus avulsion injury. In the featured case, motor-related nerve roots as well as sensory spinal nerves distal to the dorsal root ganglion were reconnected to neurons in the ventral and dorsal horns of the spinal cord by implanting nerve grafts. Peripheral and sensory functions were assessed 10 years after an accident and subsequent spinal cord surgery. The biceps stretch reflex could be elicited, and electrophysiological testing demonstrated a Hoffman reflex, or Hreflex, in the biceps muscle when the musculocutaneous nerve was stimulated. Functional MR imaging demonstrated sensory motor cortex activities on active as well as passive elbow flexion. Quantitative sensory testing and contact heat evoked potential stimulation did not detect any cutaneous sensory function, however. To the best of the authors' knowledge, this case represents the first time that spinal cord surgery could restore not only motor ...

Seckin O Ulualp - One of the best experts on this subject based on the ideXlab platform.

  • mapping regional laryngopharyngeal mechanoreceptor response
    Clinical and Experimental Otorhinolaryngology, 2014
    Co-Authors: Seckin O Ulualp
    Abstract:

    OBJECTIVES: To map mechanoreceptor response in various regions of the laryngopharynx. METHODS: Five patients with suspected laryngopharyngeal reflux and six healthy control subjects underwent stimulation of mechanoreceptors in the hypopharynx, interarytenoid area, arytenoids, aryepiglottic folds, and pyriform sinuses. The threshold stimuli evoking sensation and eliciting laryngeal adductor reflex were recorded. RESULTS: In controls, an air pulse with 2 mmHg pressure evoked mechanoreceptor response in all regions, except bilateral aryepiglottic folds of one control. In patients, stimulus intensity to elicit mechanoreceptor response ranged between 2 mmHg and 10 mmHg and varied among the regions. Air pulse intensity differed between right and left sides of laryngopharyngeal regions in the majority of patients. CONCLUSION: Laryngopharyngeal mechanoreceptor response was uniform among regions and subjects in the healthy group. Patients with suspected laryngopharyngeal reflux showed inter- and intra-regional variations in mechanoreceptor response. Laryngopharyngeal sensory deficit in patients with suspected laryngopharyngeal reflux is not limited to aryepiglottic folds.

  • Pharyngo‐UES contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.

  • pharyngo ues contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.

P Anand - One of the best experts on this subject based on the ideXlab platform.

  • return of spinal reflex after spinal cord surgery for brachial plexus avulsion injury
    Journal of Neurosurgery, 2012
    Co-Authors: Thomas Carlstedt, Peter V Misra, Anastasia Papadaki, Donald Mcrobbie, P Anand
    Abstract:

    Motor but not sensory function has been described after spinal cord surgery in patients with brachial plexus avulsion injury. In the featured case, motor-related nerve roots as well as sensory spinal nerves distal to the dorsal root ganglion were reconnected to neurons in the ventral and dorsal horns of the spinal cord by implanting nerve grafts. Peripheral and sensory functions were assessed 10 years after an accident and subsequent spinal cord surgery. The biceps stretch reflex could be elicited, and electrophysiological testing demonstrated a Hoffman reflex, or Hreflex, in the biceps muscle when the musculocutaneous nerve was stimulated. Functional MR imaging demonstrated sensory motor cortex activities on active as well as passive elbow flexion. Quantitative sensory testing and contact heat evoked potential stimulation did not detect any cutaneous sensory function, however. To the best of the authors' knowledge, this case represents the first time that spinal cord surgery could restore not only motor ...

Robert J. Toohill - One of the best experts on this subject based on the ideXlab platform.

  • Pharyngo‐UES contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.

  • pharyngo ues contractile reflex in patients with posterior laryngitis
    Laryngoscope, 1998
    Co-Authors: Seckin O Ulualp, Robert J. Toohill, Mark Kern, Reza Shaker
    Abstract:

    Background: Earlier studies have shown that stimulation of the human pharynx by injection of minute amounts of water stimulates the pharyngo-UES contractile reflex. It has been suggested that this reflex may be activated during pharyngeal reflux of gastric and/or esophageal content, thus increasing the UES pressure and possibly preventing further entry of the refluxate into the pharynx. However, the integrity of this reflex in patients with posterior laryngitis has not been studied. Aim: Evaluate the pharyngo-UES contractile reflex in a group of patients with objective findings of posterior laryngitis. Methods: Fourteen consecutive patients with posterior laryngitis (mean age, 48 ± 6 y) and 13 healthy volunteers (mean age, 53 ± 6 y) were studied by concurrent pharyngeal water stimulation and UES manometry. Results: The threshold volume required to evoke the pharyngo-UES contractile reflex in the laryngitis group (0.4 ± 0.05 mL) was significantly higher than that of the control (0.2 ± 0.04 mL) (P < .05). Following stimulation of the pharyngo-UES contractile reflex, the maximum postinjection pressure in patients (75 ± 6 mm Hg) was similar to that of the controls (78 ± 6 mm Hg). The percent increase in UES pressure following stimulation of the reflex in the laryngitis group (99% ± 15%) was significantly higher than that of controls (55% ± 11%) (P < .05). Conclusions: Compared with normal controls, a significantly larger volume of liquid is required to trigger this reflex in patients with posterior laryngitis. When triggered, the maximum UES pressure induced by the pharyngo-UES contractile reflex is similar between the two groups. These findings suggest an altered afferent sensory limb of this reflex in patients with posterior laryngitis. Key Words: Upper esophageal sphincter, reflux laryngitis, airway protection.