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PubMed2001

Group A streptococci bind to mucin and human pharyngeal cells through sialic acid-containing receptors.

The first step in the colonization of group A streptococci (Streptococcus pyogenes) is adherence to pharyngeal epithelial cells. Prior to adherence to their target tissue, the first barrier that the streptococci encounter is the mucous layer of the respiratory tract. The present study was undertaken to characterize the interaction between mucin, the major glycoprotein component of mucus, and streptococci. We report here that S. pyogenes is able to bind to bovine submaxillary mucin in solid-phase microtiter plate assays. Western blots probed with (125)I-labeled mucin and a panel of monoclonal antibodies revealed that the streptococcal M protein is one of two cell wall-associated proteins responsible for this binding. The binding was further localized to the N-terminal portion of the M molecule. Further analysis revealed that the M protein binds to the sialic acid moieties on mucin, and this interaction seems to be based on M-protein conformation rather than specific amino acid sequences. We found that sialic acid also plays a critical role in the adherence of an M6 streptococcal strain to the Detroit 562 human pharyngeal cell line and have identified alpha2-6-linked sialic acid as an important sialylated linkage for M-protein recognition. Western blot analysis of extracted pharyngeal cell membrane proteins identified three potential sialic acid-containing receptors for the M protein. The results are the first to show that sialic acid not only is involved in the binding of the streptococci to mucin but also plays an important role in adherence of group A streptococci to the pharyngeal cell surface.

Antigens, Bacterial↗

PubMed1998

Effect of chronic and acute cigarette smoking on the pharyngo-upper oesophageal sphincter contractile reflex and reflexive pharyngeal swallow.

BACKGROUND: Cigarette smoking is known to affect adversely the defence mechanisms against gastro-oesophageal reflux. The effect of smoking on the supraoesophageal reflexes that prevent aspiration of gastric contents has not been previously studied. AIMS: To elucidate the effect of cigarette smoking on two of the supraoesophageal reflexes: the pharyngo-upper oesophageal sphincter (UOS) contractile reflex; and the reflexive pharyngeal swallow. METHODS: Ten chronic smokers and 10 non-smokers were studied, before and 10 minutes after real or simulated smoking, respectively. UOS pressure and threshold volume for the reflexes were determined using a UOS sleeve assembly. Two modes of fluid delivery into the pharynx were tested: rapid injection and slow injection. RESULTS: For both rapid and slow injections, the threshold volume for triggering the pharyngo-UOS contractile reflex was significantly higher in smokers than in non-smokers (rapid: smokers 0.42 (SE 0.07) ml, non-smokers 0.16 (0. 04) ml; slow: smokers 0.86 (0.06) ml, non-smokers 0.38 (0.1) ml; p<0. 05). During rapid injection, the threshold volume for reflexive pharyngeal swallow was higher in smokers (smokers 0.94 (0.09) ml, non-smokers 0.46 (0.05) ml; p<0.05). Acute smoking further increased the threshold volume for the pharyngo-UOS contractile reflex and reflexive pharyngeal swallow during rapid injection. CONCLUSIONS: Smoking adversely affects stimulation of the pharyngo-UOS contractile reflex and pharyngeal reflexive swallow. These findings may have implications in the development of reflux related respiratory complications among smokers.

Adult↗

PubMed1990

Pharyngeal shape and dimensions in healthy subjects, snorers, and patients with obstructive sleep apnoea.

To characterise the relation between pharyngeal anatomy and sleep related disordered breathing, 17 men with complaints of snoring were studied by all night polysomnography. Ten of them had obstructive sleep apnoea (mean (SD) apnoea-hypopnoea index 56.3 (41.7), age 52 (10) years, body mass index 31.4 (5.3) kg/m2); whereas seven were simple snorers (apnoea-hypopnoea index 6.7 (4.6), age 40 (17) years, body mass index 25.9 (4.3) kg/m2). The pharynx was studied by magnetic resonance imaging in all patients and in a group of eight healthy subjects (age 27 (6) years, body mass index 21.8 (2.2) kg/m2, both significantly lower than in the patients; p less than 0.05). On the midsagittal section and six transverse sections equally spaced between the nasopharynx and the hypopharynx several anatomical measurements were performed. Results showed that there was no difference between groups in most magnetic resonance imaging measurements, but that on transverse sections the pharyngeal cross section had an elliptic shape with the long axis oriented in the coronal plane in normal subjects, whereas in apnoeic and snoring patients the pharynx was circular or had an elliptic shape but with the long axis oriented in the sagittal plane. It is suggested that the change in pharyngeal cross sectional shape, secondary to a reduction in pharyngeal transverse diameter, may be related to the risk of developing sleep related disordered breathing.

Adult↗

PubMed2002

Patterns of esophageal inhibition during swallowing, pharyngeal stimulation, and transient LES relaxation. Lower esophageal sphincter.

Lower esophageal sphincter (LES) relaxation and esophageal body inhibition co-occur during esophageal peristalsis but not necessarily during pharyngeal stimulation or transient LES relaxation (tLESR). This study examined these relationships and the impact on reflux. Nine young volunteers were studied. An artificial high-pressure zone (HPZ) was established, and pH was recorded 8 and 5 cm proximal to the LES. Pharyngeal stimulation was by water injection and gastric distension with liquid or gas. Peristalsis, pharyngeal stimulation, and spontaneous events were recorded. Swallowing relaxed the LES in 100% of trials (the HPZ in 80%) and caused no reflux. Pharyngeal stimulation relaxed the LES in two-thirds of trials, had no effect on the HPZ, and caused no reflux. Gastric distension was associated with 117 tLESRs, 48% with acid reflux, and 32% with gas reflux; there was no effect on the HPZ. We conclude that LES relaxation is a necessary but not sufficient condition for reflux. LES relaxation and esophageal body inhibition are independent events that may be concurrent (swallowing) or dissociated (tLESR).

Adolescent↗

PubMed1990

Pharyngeal and upper esophageal sphincter manometry in humans.

Manometric studies of pharyngeal-upper esophageal sphincter (UES) coordination during swallowing have proven difficult. Asymmetry of the UES makes pressure measurements with a single, unoriented transducer suspect. Perfused systems lack the necessary response rate for measuring peak pharyngeal contraction pressures. Precise quantification of the coordination of pharyngeal contractions and UES relaxations during swallowing is difficult because of rapid pressure changes. We tested a modified solid-state transducer that measures pressures over 360 degrees. This transducer was placed in the proximal UES with a second, single transducer 5 cm proximal. Data were collected and analyzed with an Apple IIe microcomputer. A computer program was developed to measure nine timing sequences, UES resting pressure, nadir of UES relaxation, and pharyngeal contraction pressures. We studied 21 volunteers with six swallows each for dry, 5, 10, and 20 ml of water. Dry swallows differed significantly (P less than 0.05) from wet (5 ml). All timing sequences became progressively longer with increasing bolus size. Residual pressures were unchanged. Timing sequences were also measured for wet (5 ml) and dry swallows in seven volunteers using a Dent sleeve and single perfused orifice in the UES; no differences were seen.

Adult↗

PubMed1990

Effect of swallowed bolus variables on oral and pharyngeal phases of swallowing.

In this investigation, we studied the effects of bolus volume and viscosity on the quantitative features of the oral and pharyngeal phases of swallowing. Concurrent videofluoroscopic and manometric studies were done in 10 healthy volunteers who were imaged in lateral projection. Videofluorography was done at 30 frames/s while concurrent manometry was done with 5 intraluminal transducers that straddled the pharynx and upper esophageal sphincter (UES). Submental electromyography was recorded also. Swallows of 2-20 ml were recorded for low-viscosity liquid barium and high-viscosity paste barium. Analysis indicated that the major effect of increases in bolus volume was an earlier onset of anterior tongue base movement, superior palatal movement, anterior laryngeal movement, and UES opening. These events provide receptive adaptation for receiving a swallowed bolus. Earlier UES opening was associated with an increase in the duration of sphincter opening and sphincter diameter. The major effects of high bolus viscosity, unrelated to bolus volume, were to delay oral and pharyngeal bolus transit, increase the duration of pharyngeal peristaltic waves, and prolong and increase UES opening. Thus the specific effect of bolus viscosity per se differs substantially from that of bolus volume. We conclude that 1) specific variables of swallowing are affected significantly by the variables of the swallowed bolus, such as volume and viscosity; 2) overall, bolus volume and viscosity affect swallowing in a different manner; and 3) the study findings have implications about the neural control mechanisms that govern swallowing as well as about the diagnosis and treatment of patients with abnormal oral-pharyngeal swallowing.

Adult↗

PubMed1997

Frequency of gastroesophageal reflux events induced by pharyngeal water stimulation in young and elderly subjects.

Earlier studies have shown that isolated complete lower esophageal sphincter (LES) relaxation occurs as a result of pharyngeal water stimulation. Association of these relaxations with gastroesophageal reflux has not been studied systematically. Our aim was to determine this association in young and elderly subjects during precibal and postprandial periods. We studied 8 young subjects and 10 elderly subjects for 1 h before and 2 h after a 1,000-cal meal. In both groups, during the precibal period, negligible LES relaxation induced by pharyngeal water stimulation resulted in gastroesophageal reflux. In the postprandial period, gastroesophageal reflux events occurred after 16% of pharyngeal water injections in young subjects and after 44% in elderly subjects (P < 0.05). Intraabdominal length of the LES in elderly subjects was significantly shorter compared with younger subjects (P < 0.05). We conclude that gastroesophageal reflux events induced by pharyngeal water stimulation in the postprandial period are significantly increased compared with those of the precibal period and are significantly more prevalent in the elderly compared with the young. These differences seem to be associated with a significantly shorter intra-abdominal segment of the LES in the elderly.

Adult↗

PubMed1985

Pharyngeal resistance in normal humans: influence of gender, age, and obesity.

Investigation into the etiology of obstructive sleep apnea is beginning to focus increasing attention on upper airway anatomy and physiology (patency and resistance). Before conclusions concerning upper airway resistance in these patients can be made, the normal range of supraglottic and, more specifically, pharyngeal resistance needs to be better defined. We measured supraglottic and pharyngeal resistances during nasal breathing in a normal population of 35 men and women. Our technique measured epiglottic pressure with a balloon-tipped catheter, choanal pressure using anterior rhinometry, and flow with a sealed face mask and pneumotachograph. Resistance was measured at a flow rate of 300 ml/s during inspiration. Men had a mean pharyngeal resistance (choanae to epiglottis) of 4.6 +/- 0.8 (SE) cmH2O X l-1 X s, whereas women demonstrated a significantly (P less than 0.01) lower value, 2.3 +/- 0.3 cmH2O X l-1 X s. Supraglottic resistance was also higher in men (P = 0.01). Age (r = 0.73, P less than 0.01) correlated closely with pharyngeal resistance in men, but no such correlations could be found in women. These results may have implications in the epidemiology of obstructive sleep apnea.

Adult↗

PubMed1986

Effect of inspiratory nasal loading on pharyngeal resistance.

Nasal obstruction has been shown to increase the number of apneas during sleep in normal subjects and in some may actually cause the sleep apnea syndrome. We postulated that the pharynx may act as a Starling resistor, where increases in negative inspiratory pressure result in elevated resistance across a collapsible pharyngeal segment. To test this theory in normal subjects we studied 10 men and 10 women during wakefulness. Pharyngeal resistance (the resistance across the airway segment between the choanae and the epiglottis) was determined in the normal state and with three inspiratory loads added externally. Flow was measured using a pneumotachometer and a sealed face mask; epiglottic pressure by a latex balloon placed just above the epiglottis and choanal pressure by anterior rhinometry. Pharyngeal resistance (measured at 300 ml/s) could thus be determined. Base-line inspiratory pharnygeal resistance was 1.6 +/- 0.2 cmH2O . l-1 . s. This increased to 2.3 +/- 0.3, 2.8 +/- 0.4, and 2.9 +/- 0.4 cmH2O . l-1 . s, respectively, with the addition of 1.3, 2.7, and 6.7 cmH2O . l-1 . s inspiratory load. The resistance at each level of load was significantly different from the base-line resistance determination (P less than 0.05) but not different from each other. We conclude that added nasal resistive loads during inspiration cause an increase in pharyngeal resistance during wakefulness but that this resistance does not increase further with additional increments of load.

Adult↗

PubMed1992

Dependence of pharyngeal resistance on genioglossal EMG activity, nasal resistance, and airflow.

We investigated the quantitative relationships among pharyngeal resistance (Rph), genioglossal electromyographic (EMGge) activity, nasal resistance (Rna), and airflow in 11 normal men aged 19-50 while they were awake. We made measurements with subjects seated with the head erect, seated with the head flexed forward approximately 40 degrees, and supine. Each subject wore a face mask connected to a pneumotachograph to measure airflow. After topical anesthesia of the nose, two catheters for measuring nasal and pharyngeal airway pressures were passed through one nostril: the nasal pressure catheter was positioned at the nasal choanae, and the pharyngeal pressure catheter was positioned just above the epiglottis. We measured EMGge activity with an intraoral surface electrode. The subjects breathed exclusively through the nose while inhaling room air or rebreathing CO2. We measured Rph, Rna, airflow, and EMGge activity at approximately 90-ms intervals throughout each inspiration. Rph was invariant as head position was changed. At any given head position, EMGge activity rose as airflow increased, and Rph remained constant. In contrast, Rna increased as airflow increased. Because Rph was constant, EMGge activity was not correlated with Rph, but EMGge was positively correlated with Rna and airflow. On the basis of the stability of Rph in the face of marked changes in collapsing forces, we conclude that the dynamic interplay of posture, head and jaw position, and upper airway muscle activity quite effectively maintains pharyngeal patency, and interactions among these factors are subtle and complex.

Adult↗

PubMed1997

Effects of a synthetic lung surfactant on pharyngeal patency in awake human subjects.

We examined the effects of separate applications of saline and a synthetic lung surfactant preparation (Surf; Exosurf Neonatal) into the supraglottic airway (SA) on the anteroposterior pharyngeal diameter (Dap) and the airway pressures required to close (Pcl) and reopen (Pop) the SA in five awake normal supine subjects. Dap, Pcl, and P(op) were determined during lateral X-ray fluoroscopy and voluntary glottic closure when pressure applied to the SA lumen was decreased from 0 to -20 cmH2O and then increased to +20 cmH2O. After Surf application and relative to control, Dap was larger for most of the applied pressures, Pcl decreased (-12.3 +/- 1.9 to -18.7 +/- 0.9 cmH2O; P < 0.01), P(op) decreased (13.4 +/- 1.9 to -6.0 +/- 3.4 cmH2O; P < 0.01), and genioglossus electromyographic activity did not change (P > 0.05). Saline had no effect. These observations suggest that pharyngeal intraluminal surface properties are important in maintaining pharyngeal patency. We propose that surfactants enhance pharyngeal patency by reducing surface tension and adhesive forces acting on intraluminal SA surfaces.

Adult↗

PubMedDate not supplied

Investigative techniques in the assessment of oral-pharyngeal dysphagia.

Oral-pharyngeal dysphagia is a common problem with a high morbidity and mortality. In general, it is not managed as well as esophageal dysphagia by gastroenterologists. A number of techniques are now available for the assessment of oral-pharyngeal dysphagia. However, a careful clinical assessment followed by a video barium swallow is all that is required for the diagnosis and management in the majority of patients. Pharyngeal manometry is likely to play an increasingly important role in the assessment of difficult or atypical cases in whom it can provide functional information not achievable with videoradiography alone. Videolaryngoscopy is a quick and simple way of detecting structural lesions and of assessing deglutitive airway protection. Videolaryngoscopy is non-invasive and easily performed in an office setting. Ultrasonography is a convenient way of assessing lingual function, but provides no more information than the video barium swallow. Pharyngeal scintigraphy is likely to assume a greater clinical relevance as a means of quantifying swallow efficiency and response to therapy.

Barium↗

PubMed1999

Pharyngeal critical pressure in patients with obstructive sleep apnea syndrome. Clinical implications.

Current evidence suggests that patients with obstructive sleep apnea (OSA) may have greater pharyngeal critical pressure (Pcrit), which reflects the increase in upper airway collapsibility. The contribution of Pcrit to the severity of OSA and to the efficacious continuous positive pressure (nCPAPeff) therapy has never been extensively described and no data are available about the interaction of Pcrit, age, and anthropometric variables. To determine the relationship between Pcrit, severity of the disease, nCPAPeff, and anthropometric variables we measured Pcrit in a group of 106 patients with OSA. Pharyngeal critical pressure was derived from the relationship between maximal inspiratory flow and nasal pressure, Pcrit representing the extrapolated pressure at zero flow. Upper airway resistance (Rus) was determined as the reciprocal of the slope (DeltaPn/DeltaVImax cm H2O/L/s) in the regression equation. In a subgroup of 68 patients, during the diagnostic night, we measured as indices of respiratory effort, the maximal inspiratory esophageal pressure (Pes) at the end of apnea (Pesmax), the overall increase from the minimum to the maximum (DeltaPes), and the rate of increase of Pes during apnea (RPes). As a group, the mean Pcrit was 2.09 +/- 0.1 cm H2O (range, 0 to 4.5) and the mean Rus was 11.1 +/- 0.5 cm H2O/L/s. Although men have greater Pcrit, pharyngeal collapsibility was influenced neither by neck size nor by body mass index (BMI). Although there was a significant relationship between Pcrit and apnea plus hypopnea index (AHI) (r = 0.23, p = 0.02), neck circumference was the stronger predictor of apnea frequency, with Pcrit contributing only to the 3% of the variance. In the group of patients as a whole, a model including AHI, BMI, Rus, and Pcrit explained the 36% of the variance in nCPAPeff, with a greater contribution of AHI, Pcrit accounting for only 3% of the variation. In patients for whom the measure of respiratory effort was obtained, 42% of the variance in nCPAPeff was explained by RPes (33%) and BMI. From these results we conclude that Pcrit alone does not yield a diagnostically accurate estimation of OSA severity and nCPAPeff. Although individual collapsibility may predispose to pharyngeal collapse, upper airway occlusion may require the combination of several factors, including obesity, upper airway structure, and abnormalities in muscle control.

Anthropometry↗

PubMed1987

Pharyngeal size and resistance in obstructive sleep apnea.

Although anatomic and physiologic abnormalities of the upper airway are thought to be important in the pathogenesis of obstructive sleep apnea (OSA), the relative contributions of these factors have not been elucidated. We therefore measured pharyngeal cross-sectional area (PCSA) and pharyngeal air-flow resistance (Rp) in 12 overweight men with severe symptomatic OSA (mean apnea plus hypopnea index [AHI], 66.9 +/- 6.0 events per hour) and in 17 age- and weight-matched control subjects without spontaneous complaints of OSA symptoms (mean AHI, 4.9 +/- 1.6 events per hour). During wakefulness, PCSA was assessed during breath cessation at FRC by computed tomography (CT) and Rp by measuring inspiratory air-flow resistance between the choanae and epiglottis. No measure of PCSA differed significantly between patients and control subjects, and only 1 measure of PCSA, minimal pharyngeal area, correlated with AHI in all subjects (r = -0.38, p less than 0.05). In contrast, Rp was significantly higher (p less than 0.05) in patients (6.9 +/- 1.0 cm H2O/L/s) than in all control subjects (4.2 +/- 0.5 cm H2O/L/s) and correlated significantly with AHI (r = 0.53, p less than 0.01). We conclude that increased inspiratory resistance to air flow in the naso-oropharynx is present during wakefulness in overweight men with OSA, when compared with matched control subjects without symptomatic OSA, and is associated with disordered breathing during sleep. This occurs even though computed tomography is unable to demonstrate that pharyngeal size during wakefulness at FRC is significantly different between patients and control subjects. These observations suggest that the ability to dilate the pharynx during inspiration may be defective in patients with OSA.

Airway Resistance↗

PubMed2001

Effects of gum chewing on pharyngeal and esophageal pH.

We investigated the effects of gum chewing on pharyngeal and esophageal pH levels in patients with laryngopharyngeal reflux (LPR) who were undergoing reflux testing. Forty consecutive, unselected, adult patients who were undergoing ambulatory double-probe (simultaneous pharyngeal and esophageal) pH monitoring for diagnosis of LPR were asked to chew 2 sticks of gum 4 times during their pH studies. Twenty subjects chewed regular sugarless gum, and 20 subjects chewed a sugarless gum containing bicarbonate. The subjects recorded the beginning and end of each gum-chewing period. The mean pH values for the gum-chewing intervals and for comparable pre-gum-chewing intervals were analyzed statistically for both the pharyngeal and esophageal probe data. The regular gum group and the bicarbonate gum group were analyzed separately. In addition, the gum-chewing pH data were compared to controls, ie, normal postcibal buffering effects. The data show that gum chewing consistently increases esophageal and pharyngeal pH, and that bicarbonate gum causes greater increases than regular gum. For patients with LPR, gum chewing appears to be a useful adjunctive antireflux therapy.

Acid-Base Equilibrium↗

PubMed1995

Pharyngeal and pharyngolaryngeal bands: report of an unusual combination of congenital anomalies.

Multiple abnormal pharyngeal and pharyngolaryngeal bands were present in a child presenting with diffuse interstitial pulmonary fibrosis. The soft palate was fused to the posterior pharyngeal wall. Instead of there being facial pillars, a muscular band on either side extended from the base of the tongue to the lateral pharyngeal walls. There was neither tonsil nor adenoid tissue present. The epiglottis was tethered to the posterior pharyngeal wall by bands from its lateral aspects. The right arytenoid mound was tethered to the posterior wall of the hypopharynx. It is postulated that these arose from a failure of development of the second branchial pouch.

Branchial Region↗

PubMed1996

Inflammatory myopathy causing pharyngeal dysphagia: a new entity.

Seven patients presented to our swallowing center with solid food dysphagia. The age range at presentation was 69 to 90 years. All patients had normal findings on neurologic evaluation, and in those patients undergoing electromyography and nerve conduction studies, results of all such tests were also normal. Pooling of saliva in the pharyngeal recesses was noted on fiberoptic laryngoscopy in most cases. The swallowing videofluoroscopy findings were strikingly similar. All patients had a prominent cricopharyngeus muscle, and some had a prominence in a more proximal portion of the inferior constrictor muscle. All patients had decreased epiglottic tilt and moderate or severe residue in the pharyngeal recesses. Three patients underwent pharyngoesophageal sphincter myotomy. Biopsies of the omohyoid and cricopharyngeus muscles showed inflammatory myopathy with no evidence of inclusion bodies. This is a distinct clinical entity defined by isolated pharyngeal dysphagia in elderly patients with a unique videofluoroscopic appearance and pharyngeal myopathy.

Aged↗

PubMed1989

Quantitative assessment of pharyngeal bolus driving forces.

This study analyzes the differences between wet and dry swallows; a manofluorogram is used to determine forces that affect pharyngeal bolus flow. By defining bolus pressures, many of the limitations of pharyngeal manometry are surmounted. This makes manometry a more useful clinical tool. The study results indicate that only a small portion of pharyngeal-generated pressure is directly applied to the bolus. The manofluorogram demonstrates that bolus transit relies on the synergistic action of two pumps--the oropharyngeal propulsion pump and the hypopharyngeal suction pump. A technique is illustrated for quantifying the forces that affect bolus flow. Quantification of force can differentiate abnormal forces responsible for lingual, pharyngeal, and hypopharyngeal pathology in dysphagic patients. The degrees of impairment can be measured.

Adult↗