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At least 919 records · Page 51Linked to original sources
PubMed1986

Swallow-evoked peristalsis in opossum esophagus: role of cholinergic mechanisms.

This study examined the role of cholinergic mechanisms in esophageal smooth muscle of anesthetized opossums. Swallow-induced motility was recorded manometrically before and after treatment with physostigmine or metoclopramide. At the 5-cm site above lower esophageal sphincter (LES) the latency, duration, and amplitude of swallow-evoked contractions were 2.1 +/- 0.12 (SE) s, 1.8 +/- 0.31 s, and 74.5 +/- 6.1 mmHg, respectively. At the 1-cm site the respective values were 4.6 +/- 0.38 s, 3.8 +/- 0.24 s, and 42.0 +/- 4.6 mmHg. The calculated speed of peristalsis was 1.72 +/- 0.21 cm/s. After intravenous treatment with the physostigmine (100 micrograms X kg-1 X h-1), each swallow produced contractions that were simultaneous, repetitive, and of long duration. The values of duration and amplitude of contraction at the 5- and 1-cm site after physostigmine treatment were significantly higher than controls (P less than 0.01). There was a significant decrease in the latency of contraction at all sites. This resulted in a significant faster speed of peristalsis. Atropine (30 micrograms/kg iv) reversed the influence of physostigmine, resulting in a significantly slower speed of peristalsis. Metoclopramide (10 mg/kg iv) resulted in several changes in swallow-evoked contractions similar to those observed after physostigmine treatment. These data suggest that alteration in cholinergic mechanisms results in disordered esophageal peristalsis in the opossum.

Animals↗
PubMed1996

Effect of morphine and naloxone on motor response of the human esophagus to swallowing and distension.

The effect of morphine on esophageal motility has been little explored. In eight healthy volunteers, we studied the effect of intravenous morphine (100 micrograms/kg) followed 60 min later by intravenous naloxone (80 micrograms/kg) and of intravenous naloxone alone (80 micrograms/kg) on the esophageal motor response to swallowing and 30-s intraluminal distensions(4, 6, 8, and 10 ml) during two separate experiments. Morphine increased (P < 0.01) the velocity but did not alter the amplitude or duration of primary peristalsis, and it decreased the duration and magnitude of swallow-induced lower esophageal sphincter (LES) relaxation (P < 0.01). It also markedly increased contractile activity below the balloon at high distending volumes (P < 0.05) and decreased the magnitude of distension-induced LES relaxation (P < 0.05) but did not affect contractile activity above the balloon. All effects were reversed by naloxone. The latter alone did not influence the esophageal response to swallowing or distension. The conclusions are that 1) morphine exerts effects on the response of the human esophagus to swallowing and intraluminal distension that are consistent with an action at the level of the inhibitory neural pathways, 2) these effects occur through opioid receptors, and 3) endogenous opioids do not seem to control esophageal motility, at least through mu-receptors.

Adult↗
PubMed1994

Ovine fetal swallowing and renal responses to oligohydramnios.

Amniotic fluid (AF) volume regulation is dependent on a balance between fluid production and fluid resorption. We examined the effects of reduced AF volume on AF production by fetal urine and resorption by fetal swallowing and the response of these parameters to AF volume replacement. Eight time-dated pregnant ewes (125 +/- 1 days gestation) were studied before (day 1) and after (day 3) AF and fetal urine drainage. Drainage resulted in a significant decrease in AF volume (415 +/- 89 to 157 +/- 36 ml). Fetal urine osmolality increased (139 +/- 10 to 286 +/- 33 mosmol/kgH2O), while urine flow did not change significantly (0.31 +/- 0.04 to 0.23 +/- 0.06 ml/min), resulting in nonsignificant increases in osmolar, sodium, and chloride excretions. Fetal electromyographic swallowing activity decreased 30% (1.0 +/- 0.1 to 0.7 +/- 0.1 swallows/min; P < 0.05), while net esophageal flow decreased 74% (0.31 +/- 0.12 to 0.07 +/- 0.04 ml/min; P < 0.05). On day 4, 0.15 M NaCl (500 ml; 37 degrees C) was administered into the AF over 30 min. During the 2 h after reinfusion, urine flow (0.29 +/- 0.07 to 0.40 +/- 0.09 ml/min) and osmolar sodium and chloride excretion significantly increased, though fetal swallowing activity and esophageal flow did not change. Thus the ovine fetus responded to reduced AF volume by maintaining AF production and decreasing AF resorption. In response to AF replacement, urine flow increased while fetal swallowing activity did not change, consistent with an intramembranous pathway for fetal AF resorption.

Amniotic Fluid↗
PubMed1994

Coordination of oral cavity and laryngeal movements during swallowing.

In this study, dynamic imaging was used to track the movements of oral cavity and laryngeal structures during swallowing in 10 normal adults subjects. The movements of tiny lead pellet markers attached to the lips, tongue, mandible, and soft palate, as well as anatomic landmarks on the hyoid bone, were measured in relation to a reference pellet affixed to the upper central incisors. Sagittal views of the oral cavity were obtained using standard videofluorography. Each subject produced 10 swallows of 12 ml of tap water followed by 5 swallows with a bite block placed between the molars. The recorded video images were input to a microcomputer where the x- and y-coordinates of the pellets were measured. Results of the analyses revealed considerable temporal overlap in the timing of oral cavity and laryngeal movements, widespread individual variability in coordination patterns and movement trajectories, and selective effects of the bite block. These data suggest the existence of individual adaptive strategies in the programming and control of swallowing movements.

Adult↗
PubMed2005

Variability of swallowing performance in intact, freely feeding aplysia.

Variability in nervous systems is often taken to be merely "noise." Yet in some cases it may play a positive, active role in the production of behavior. The central pattern generator (CPG) that drives the consummatory feeding behaviors of Aplysia generates large, quasi-random variability in the parameters of the feeding motor programs from one cycle to the next; the variability then propagates through the firing patterns of the motor neurons to the contractions of the feeding muscles. We have proposed that, when the animal is faced with a new, imperfectly known feeding task in each cycle, the variability implements a trial-and-error search through the space of possible feeding movements. Although this strategy will not be successful in every cycle, over many cycles it may be the optimal strategy for feeding in an uncertain and changing environment. To play this role, however, the variability must actually appear in the feeding movements and, presumably, in the functional performance of the feeding behavior. Here we have tested this critical prediction. We have developed a technique to measure, in intact, freely feeding animals, the performance of Aplysia swallowing behavior, by continuously recording with a length transducer the movement of the seaweed strip being swallowed. Simultaneously, we have recorded with implanted electrodes activity at each of the internal levels, the CPG, motor neurons, and muscles, of the feeding neuromusculature. Statistical analysis of a large data set of these recordings suggests that functional performance is not determined strongly by one or a few parameters of the internal activity, but weakly by many. Most important, the internal variability does emerge in the behavior and its functional performance. Even when the animal is swallowing a long, perfectly regular seaweed strip, remarkably, the length swallowed from cycle to cycle is extremely variable, as variable as the parameters of the activity of the CPG, motor neurons, and muscles.

Action Potentials↗
PubMed1992

Membrane potential changes of phrenic motoneurons during fictive vomiting, coughing, and swallowing in the decerebrate cat.

1. The patterns of membrane potential changes of phrenic motoneurons were compared during fictive vomiting, fictive coughing, and fictive swallowing in decerebrate, paralyzed cats. These fictive behaviors were identified by motor nerve discharge patterns similar to those recorded from the muscles of nonparalyzed animals. Phrenic motoneurons (n = 54) were identified by antidromic activation from the thoracic phrenic nerve. Intracellular recordings were obtained from 27 motoneurons during fictive vomiting, 40 during fictive coughing, and 27 during fictive swallowing. Sixteen motoneurons were recorded during both fictive coughing and fictive swallowing, eight during both fictive coughing and fictive vomiting, and two during both fictive vomiting and fictive swallowing. Seven motoneurons were studied during all three behaviors. 2. Fictive vomiting, typically evoked by electrical stimulation of abdominal vagal afferents, was characterized by a series of bursts of coactivation of phrenic and abdominal motor nerves, culminating in an expulsion phase in which abdominal discharge was prolonged both with respect to phrenic discharge and to abdominal discharge during the preceding retching phase. During fictive vomiting, phrenic motoneurons depolarized abruptly, and the amplitude of depolarization was significantly greater than during control inspirations. They then repolarized slowly throughout the phrenic burst, rapidly repolarizing at the end of each phrenic burst during retching and reaching a level similar to that observed during expiration. During the expulsion phase, the pattern was initially the same. However, after the cessation of phrenic discharge, the membrane potential repolarized slowly until the end of the abdominal burst, exhibiting greater synaptic noise than during expiration. One phrenic motoneuron, presumably innervating the periesophageal region of the diaphragm, received a strong hyperpolarization just before the onset of the emetic episode and fired for shorter periods during fictive vomiting than did other phrenic motoneurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Safety of sublingual-swallow immunotherapy in children and adults.

BACKGROUND: Immunotherapy is an established treatment of allergic diseases. The safety of this treatment, particularly when administered without direct medical surveillance, as in the case of the sublingual-swallow route needs to be established. The aim of this paper is to review the safety of the sublingual-swallow immunotherapy as reported in eight double-blind, placebo-controlled trials carried out in France, Italy and Greece. METHODS: Six hundred and ninety subjects, 472 adults and 218 children, took part in trials of specific immunotherapy (SIT) for the treatment of rhinoconjunctivitis and/or asthma. Three hundred and forty-seven patients received SIT and 343 patients received placebo. Treatment with specific immunotherapy with allergen extracts or placebo was administered using the sublingual-swallow technique. The allergens administered were grass, ambrosia, parietaria and olive pollens, and mites. The daily dose taken during maintenance therapy ranged from 100 to 300 IR (index of reactivity) and cumulative doses ranged from 4,500 to 104,000 IR. Treatment duration ranged from 4 months to 2 years. Adverse events reported either spontaneously by the patient or on direct questioning by the investigator were analysed. RESULTS: One hundred and forty-five unusual events were reported in the subjects receiving active SIT and 79 in those receiving placebo (p < 0.001). Of these 85 were children aged 15 years or less (50 received active SIT, 35 placebo) and 139 were adults (95 received SIT, 44 placebo). Unusual events involving the buccal cavity (61 SIT, 13 placebo) and the gastro-intestinal tract (47 SIT, 15 placebo) were significantly more frequent in the SIT-treated patients (p < 0.001). Wheezing (9 SIT, 21 placebo) was more frequent in the placebo-treated patients (p < 0.05). There were no differences in the frequency of unusual events between adults and children and in the frequency of events involving other body systems. No event was reported as serious. Two events reported as laryngeal oedema were not considered to be accurate descriptions. CONCLUSIONS: No serious adverse event was reported in the studies monitored, confirming the good safety profile of the sublingual-swallow method both in children and adults with rhinitis or moderate asthma.

Administration, Sublingual↗
PubMed2000

Nasal continuous positive airway pressure and weight loss improve swallowing reflex in patients with obstructive sleep apnea syndrome.

We have recently reported that swallowing reflex is impaired in patients with obstructive sleep apnea syndrome (OSAS). However, the effects of OSAS treatment on swallowing function in these patients have not been reported. Here we report 2 cases of OSAS in whom swallowing reflex was impaired before the start of nasal continuous positive airway pressure (NCPAP) and improved 1 year after NCPAP. These cases suggest that impaired swallowing reflex may be reversible by OSAS treatment.

Administration, Intranasal↗
PubMed2002

Effects of different fluids on the relationship between swallowing and breathing during nutritive sucking in neonates.

This study in 10 term infants investigated the effects of different fluids on the coordination between swallowing and breathing during bottle feedings. Sucking pressure, swallowing, breathing and O(2) saturation were examined in each infant during bottle feedings with breast milk, formula and distilled water. When receiving breast milk, the infants showed a significantly higher breathing rate than with the other liquids. Swallows followed by inspiration were demonstrated less often with breast milk compared with formula or distilled water. In conclusion, expressed breast milk is suitable for neonates because better coordination between swallowing and breathing could be obtained and subclinical aspiration could be prevented.

Bottle Feeding↗
PubMed2002

Swallowing and stroke. Neurological effects and recovery.

The development of imaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scanning has allowed non-invasive imaging of the brain, to a greater detail, that in the past was not possible. These imaging modalities have allowed the study of the cortical control of swallowing both in the healthy volunteers and the stroke patient. It has become increasingly obvious that swallowing is complex and its recovery following stroke even more so. Swallowing is represented in many areas of the hemisphere and is affected in many different ways following stroke. In most, recovery is spontaneous, but in some it is slow or non-existent. Studies using direct and transcranial electrical stimulation and pharmacological agents have shown interesting results in the recovery of swallowing following stroke.

Cerebral Cortex↗
PubMedDate not supplied

Relationship between speech and swallowing disorders in patients with neuromuscular disease.

The intelligibility of monosyllabic speech, word speech, and conversational speech was evaluated in 113 dysarthric speakers, and the presence and severity of swallowing disorders were evaluated using videofluoroscopic and bedside examinations. The results revealed a high correlation between swallowing function and all levels of speech intelligibility. Furthermore, the prevalence of concomitant dysphagia in dysarthric patients was quite high regardless of the primary etiology and time elapsed since the onset. However, the relationship between the two functions is more complex than is initially apparent. The prevalence and severity of dysphagia vary markedly according to the type of dysarthria. Patients in the flaccid, spastic, and mixed categories encompass a broad range of severity levels with many individuals being severely impaired, while patients in the ataxic, hypokinetic, and unilateral upper motor neuron categories seldom have severe concomitant swallowing problems. Furthermore, the correlation coefficient between conversational intelligibility and swallowing function varies considerably according to the type of dysarthria. The correlation was not significant in the flaccid, hypokinetic, and UUMN dysarthria groups. Based on these findings, we discuss herein the clinical management of dysarthric patients with dysphagia.

Adult↗
PubMedDate not supplied

Effectiveness of screening aqueous contrast swallow in detecting clinically significant anastomotic leaks after esophagectomy.

BACKGROUND: Aqueous contrast swallow study is recommended as a screening procedure for the evaluation of esophageal anastomotic integrity following esophagectomy. The aim of this study was to assess the accuracy of water-soluble contrast swallow screening as a predictor of clinically significant anastomotic leak in patients with esophagectomy. PATIENTS AND METHODS: The records of 505 consecutive patients undergoing esophagectomy in Mayo Clinic from January 1991 through December 1995 were retrospectively reviewed. 464 (92%) patients had water-soluble contrast swallows performed in the early postoperative period (median postoperative day 7, range 4-11 days). RESULTS: A total of 39 radiological leaks were obtained but only 17 of these had clinical signs of anastomotic leakage. Furthermore, 25 patients who had normal swallow study developed a clinical anastomotic leak. There were therefore 22 (4.7%) false positive and 25 (5.4%) false negative results giving values for the specificity, sensitivity and false negative error rate of the radiological examination of 94.7, 40.4, and 59.5% respectively. Aspiration of the contrast agent was noted on fluoroscopy in 30 (6.5%) patients. Only 2 (0.4%) patients developed aqueous contrast agent-caused aspiration pneumonia. There was no procedure-related mortality. CONCLUSION: While radiological assessment of esophageal anastomoses in the early postoperative period using aqueous contrast agents appears to be a relatively safe procedure, the poor sensitivity and high false negative error rate of this technique, when performed on postoperative day 7 and in a series with clinical anastomotic leak rate of 9%, is insufficient for it to be worthwhile as a screening procedure.

Adolescent↗
PubMed2005

Swallow syncope, a case report and review of the literature.

Swallow syncope is a relatively rare syndrome that is treatable when diagnosed. A 66-year-old woman was referred to the department of cardiology because she had been suffering from recurrent syncopal attacks associated with swallowing. An ambulatory electrocardiogram revealed atrial and ventricular asystoles immediately after swallowing soup or tea that were reproducible (max. RR 3.5 s). An electrophysiological study did not detect sinus nodal or atrioventricular nodal dysfunction. The patient had no underlying esophageal disease or cardiac disorder. The patient's symptoms resolved after permanent pacemaker implantation. This report reviews the diagnosis, mechanism and management of swallow syncope.

Aged↗
PubMed1991

Ovine fetal breathing and swallowing activity in response to plasma glucose changes.

Fetal swallowing activity generally occurs simultaneously with fetal breathing movements (FBM) in sheep. The present study investigated the FBM and swallowing responses to altered fetal plasma glucose. Fetal lambs were chronically prepared with laryngeal, esophageal and diaphragm electromyogram (EMG) wires, an esophageal flow probe and vascular catheters. Beginning at 138 +/- 1 day, FBM and swallowing were monitored during control periods and in response to intravenous glucose infusions (14 mg/kg/min for 120 min) to fetuses of fed and fasted ewes. Glucose infusions to fetuses of fed ewes resulted in significant increases in fetal plasma glucose (21.2 +/- 0.7 to 40.5 +/- 1.9 mg/dl) and time breathing (46.2 +/- 6.3 to 60.0 +/- 9.5 min/2 h). In response to maternal fasting, fetal glucose levels (13.4 +/- 1.0 mg/dl) and time breathing (23.0 +/- 7.2 min/2 h) decreased significantly. Glucose infusion to fetuses of fasted ewes resulted in significant increases in time breathing (50.3 +/- 13.4 min/2 h) and diaphragmatic EMG activity (1,295 +/- 654 to 3,012 +/- 1,182 spikes/2 h). There was no change from basal levels of fetal EMG swallows (83.2 +/- 4.3 swallows/2 h) or esophageal flow (40.8 +/- 7.9 ml/2 h) in response to maternal fasting or fetal glucose infusions.

Animals↗
PubMed2000

Pharyngeal pressure analysis by the finite element method during liquid bolus swallow.

The human pharynx is unique, acting as a complex interchange between the oral cavity and the esophagus, and between the nasal cavity and the lungs. It is actively involved in the transport of food and liquid, producing the forces that guide the bolus into the upper esophagus and away from the adjacent larynx and lungs. This study developed a biomechanical computer model of the human pharynx, utilizing a finite element method (FEM). Control 2-dimensional cine computed tomography images were obtained during 10-mL barium paste swallows at 8 levels extending from the tongue base to the cricopharyngeal level in order to encompass the entire pharynx. Three-dimensional finite element models of the pharynx were reconstructed from the geometric information obtained from the images at each level. Using an inverse dynamic approach with the addition of known tissue properties, we analyzed the 8 models under estimated pressure histories during swallow. Within each model, changes in the cross-sectional intraluminal area were calculated and compared with the area from the computer-generated FEM model. Area matching allowed estimation of intraluminal pressure gradients during swallow. The estimated pressure gradients were distributed through a range from 10 to 55 mm Hg, varying from one region to another and showing different patterns for the upper 4 levels and the lower 4 levels. The contraction velocity for the upper 4 levels was much higher than that for the lower 4 levels. The higher contraction velocities and pressure gradients in the upper levels are consistent with the bolus velocities required for efficient swallow.

Biomechanical Phenomena↗
PubMed2000

Pediatric laryngopharyngeal sensory testing during flexible endoscopic evaluation of swallowing: feasible and correlative.

Laryngopharyngeal sensory testing can predict aspiration risk in adult patients. Its feasibility and potential role in the evaluation of pediatric swallowing is undetermined. The goals of this study were to determine the feasibility of performing laryngopharyngeal sensory testing in awake pediatric patients and to assess whether the sensory testing results correlated with aspiration during a feeding assessment or correlated with a history of pneumonia. Fiberoptic endoscopic evaluation of swallowing with sensory testing was performed in 100 pediatric patients who were evaluated for feeding and swallowing disorders. The swallowing function parameters evaluated were pooled secretions, laryngeal penetration, and aspiration. The laryngopharyngeal sensory tests were performed by delivering a pressure-controlled and duration-controlled air pulse to the aryepiglottic fold through a flexible laryngoscope to induce the laryngeal adductor response (LAR). The air pulse stimulus ranged in intensity from 3 to 10 mm Hg. The patients tested ranged from 1 month to 24 years of age, with a median age of 2.7 years. Sensory testing was completed in 92% of patients. Patients who had an LAR at less than 4 mm Hg rarely if ever had episodes of laryngeal penetration or aspiration. Those with an LAR at 4 to 10 mm Hg had variable amounts of aspiration and laryngeal penetration. The LAR could not be elicited at the maximum level of intensity (10 mm Hg) in 22 patients, who demonstrated severe laryngeal penetration and/or aspiration. Elevated laryngopharyngeal sensory thresholds correlated positively with previous clinical diagnoses of recurrent pneumonia, neurologic disorders, and gastroesophageal reflux, and correlated positively with findings of pooled secretions, laryngeal penetration, and aspiration. Laryngopharyngeal sensory testing in children is feasible and correlative.

Adolescent↗
PubMedDate not supplied

A tympanometric pressure swallow test for assessment of eustachian tube function.

Normal Eustachian tube function is necessary for maintaining healthy middle ear conditions. A tympanometric pressure swallow test is proposed which can be used to assess Eustachian tube function behind an intact tympanic membrane. In general, after recording a baseline tympanogram, mechanically created positive and negative air pressures are created in a hermetically sealed ear canal causing increased pressure on the middle ear air cushion. The patient is then asked to swallow. Preliminary clinical findings in ears with apparent normal Eustachian tube function show that a shift in the peak pressure point of the tympanogram occurs when the tympanogram is recorded again, implying that the Eustachian tube opens and equalizes middle ear air pressure. Positive canal pressure swallow maneuvers show a peak pressure shift to a negative value, whereas negative pressure swallow maneuvers show a peak pressure shift to a positive value.

Deglutition↗
PubMedDate not supplied

Role of afferent sensors in the initiation of swallowing in man.

Chewing and swallowing sounds that were recorded on magnetic tape by means of a paralaryngeally placed contact microphone were used to evaluate temporal relationships of the events of the swallowing cycle in young women. Temporal inter-event parameters indicate a reflex nature for the initiation of swallowing, and the effects of topical anesthesia suggest a triggering mechanism for swallowing similar to the gating theory for pain proposed by Melzack and Wall.

Administration, Topical↗