The impact of vaccination on the burden of invasive pneumococcal disease from a nationwide surveillance program in Lebanon: an unexpected increase in mortality driven by non-vaccine serotypes

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on the burden of invasive pneumococcal disease (IPD) and serotype distribution was examined across age groups from data collected by the Lebanese Inter-Hospital Pneumococcal Surveillance Program.

METHODS

Between 2005 and 2020, 593 invasive Streptococcus pneumoniae isolates were collected from 79 hospitals throughout Lebanon. Serotypes and antimicrobial resistance (AMR) profiles were identified, and trends compared over 3 eras: PCV7, post-PCV7/ pre-PCV13, and PCV13 eras.

RESULTS

The prevalence of PCV7 serotypes decreased significantly from 43.6% in the PCV7 era to 17.8% during the PCV13 era (p<0.001). PCV13-only serotypes remained stable in the PCV13 compared to the post-PCV7 eras, especially serotypes 1 and 3, whereas non-vaccine types (NVT) increased throughout the study period, especially 24 and 16F. The mortality rate increased substantially from 12.5% (PCV7 era) to 24.8% (PCV13 era). A significant decrease in AMR was observed across the three study eras.

CONCLUSION

PCVs substantially impacted IPD and AMR in vaccinated and unvaccinated populations despite an increase in mortality driven by NVT. Broadening the recommendation of vaccination to include older age-groups, using higher valency vaccines, and implementing stringent antimicrobial stewardship are likely to further impact the burden of IPD.

Wide Variability in the Sensitivity and Specificity of Rotavirus Immunoassay Diagnostic Kits in Practice

INTRODUCTION

Most hospitals rely on rapid antigen-detection kits for the diagnosis of rotavirus infection. Several small studies reviewed the sensitivity and specificity of some of these kits. These studies showed discrepancy in results obtained for sensitivity and specificity that varied according to the type of kit used, area of study, and type of test used as standard for diagnosis of rotavirus infection. The objective of the study is to determine the sensitivity and specificity of five commonly used rotavirus immunoassay kits in comparison to RT-PCR as standard.

METHODOLOGY

Stool samples (N = 1,414) collected from children under 5 years of age hospitalized with gastroenteritis were tested for rotavirus by immunoassay kits and RT-PCR in a prospective hospital-based surveillance study conducted at 7 centers in Lebanon. Concordance and discrepancy between the two methods was used to calculate sensitivity and specificity, using RT-PCR as the "gold standard".

RESULTS

The sensitivity and specificity were respectively 95.08% and 86.62% for the SD Bioline® (Standard Diagnostics, Inc, South Korea) kit calculated on 645 samples, 65.86% and 45.90% for the VIROTECT® (Trinity Biotech, Ireland) kit calculated on 327 samples, 83.9% and 64.2% for the Rota-Strip (C-1001) (Coris Bioconcept, Belgium) calculated on 95 samples, 52.3% and 10.9% for the Acon® (Acon Laboratories, Inc, California, USA) kit calculated on 122 samples, 68.1% and 20% for the VIKIA® Rota-Adéno (Biomerieux, France) kit calculated on 32 samples.

CONCLUSION

A wide discrepancy was detected between the calculated and advertised sensitivity and specificity for most of the kits.

Placement of Labcor Pulmonary Conduit Results in a High Incidence of Postoperative Fever

BACKGROUND

Fever in the postoperative period in cardiac patients is common. The purpose of this study is to recognize the risk factors for prolonged postoperative fever in cardiac patients with pulmonary conduit insertion.

METHODS

Patients were identified retrospectively by looking at the International Classification of Diseases, Ninth Revision, Clinical Modification procedure code for pulmonary conduit insertion between June 2009 and December 2015 at the American University of Beirut Medical Center. Data about preoperative, perioperative, and postoperative variables were collected. Data entry and analysis were performed using SPSS version 22.

RESULTS

The study identified 59 patients. The most common type of pulmonary conduit used was the Contegra type (57.6%) (n = 34), followed by the Labcor type (20.3%; n = 12). Postoperative fever occurred in 61% of patients (n = 36). Fourteen patients (38.8%) had a prolonged fever that lasted for more than seven days. Prolonged postoperative fever was significantly associated with the Labcor pulmonary conduit (P value < .001) and a longer duration of pacing wires (P value: .039). Significantly prolonged fever that lasted for more than 21 days occurred in five patients who all had inserted the Labcor pulmonary conduit.

CONCLUSIONS

The Labcor pulmonary conduit type is a risk factor for prolonged postoperative fever. The protracted use of pacing wires could be a consequence of the prolonged fever rather than a cause. In the absence of a demonstrable infectious etiology for prolonged postoperative fever in cardiac patients with pulmonary conduit insertion, the Labcor pulmonary conduit could be the underlying cause. Alternative management of such cases may lead to decreased antibiotic use and morbidity.

Molecular epidemiology and genetic characterization of influenza B virus in Lebanon during 2016-2018

BACKGROUND

Influenza B viruses are a major cause of serious acute respiratory infections in humans.

METHODS

Nasopharyngeal swabs were collected from subjects with influenza-like illness during October 2016-June 2018 and screened for influenza A and B. The hemagglutinin (HA) and neuraminidase (NA) genes of the Lebanese influenza B specimens were sequenced and phylogenetically compared with the vaccine strains and specimens from the Eastern Mediterranean Region and Europe.

RESULTS

Influenza A and B viruses co-circulated between October and May and peaked between January and March. During the 2016-2017 season, A/H3N2 (33.4%) and B/Yamagata (29.7%) were the predominantly circulating viruses followed by B/Victoria and A/H1N1pdm09 viruses. During the 2017-2018 season, A/H3N2 (31.5%) and A/H1Npdm09 (29.3%) were most prevalent with co-circulation of B/Yamagata and to a lesser extent B/Victoria viruses. The B/Yamagata specimens belonged to clade-3 while the B/Victoria belonged to clade-1A. None of the analyzed specimens had a mutation known to confer resistance to NA inhibitors (NAIs).

CONCLUSION

Multiple subtypes of influenza co-circulate each year in Lebanon with a peak between January and March. The trivalent vaccine included a B/Victoria strain which mismatched the B/Yamagata lineage that predominated during the study period, highlighting the importance of quadrivalent vaccines.

Prevalence and characteristics of acute respiratory virus infections in pediatric cancer patients

Background

Patients with pediatric cancer have a higher risk of morbidity and mortality because of respiratory viral infections than other patient populations.

Objectives

To investigate the causative viruses of respiratory infections and their burden among patients with pediatric cancer in Lebanon.

Study design

Nasopharyngeal swabs along with clinical and demographic data were collected from patients with pediatric cancer presenting febrile episodes with upper respiratory tract symptoms. Total nucleic acid was extracted from specimens followed by the real‐time PCR analysis targeting 14 respiratory viruses to estimate the frequency of infections.

Results

We obtained 89 nasopharyngeal swabs from patients with pediatric cancer (mean age, 5.8 ± 4.2 years). Real‐time PCR confirmed viral infection in 77 swabs (86.5%). Among these, 151 respiratory viruses were detected. Several viruses cocirculated within the same period; respiratory syncytial virus (RSV) being the most common (45.45%), followed by parainfluenza virus (PIV; 26%), influenza type B (26%), human metapneumovirus (24.6%), and human coronavirus (HCoV; 24.6%). Coinfections were detected in 55% of the subjects, and most of them involved RSV with one or more other viruses. A strong correlation was found between PIV, Flu (influenza of any type), RSV, and HCoV with the incidence of coinfections. RSV was associated with lower respiratory tract infections, nasal congestion, bronchitis, and bacteremia. HCoV was associated with bronchiolitis; rhinovirus was associated with hospital admission.

Conclusion

Patients with pediatric cancer have a high burden of respiratory viral infections and a high incidence of coinfections. Molecular diagnostics can improve management of febrile episodes and reduce antibiotic use.

Respiratory viruses are leading cause of ARTI in pediatric cancer patients.

Coinfections are common among febrile pediatric cancer patients.

RSV was the most common in mono‐ and coinfections among pediatric cancer patients.

RSV, PIV, Flu, HCoV are associated with coinfections.

Molecular diagnostics permit rapid and sensitive diagnostics and limit antibiotic abuse.

Detection of ON1 and novel genotypes of human respiratory syncytial virus and emergence of palivizumab resistance in Lebanon

Respiratory syncytial virus (RSV) is a common cause of respiratory tract infections in children and immunocompromised individuals. A multi-center surveillance of the epidemiologic and molecular characteristics of RSV circulating in Lebanon was performed. The attachment (G) and fusion (F) glycoproteins were analyzed and compared to those reported regionally and globally. 16% (83/519) of the nasopharyngeal swabs collected during the 2016/17 season tested positive for RSV; 50% (27/54) were RSV-A and 50% (27/54) were RSV-B. Phylogenetic analysis of the G glycoprotein revealed predominance of the RSVA ON1 genotype, in addition to two novel Lebanese genotype variants, hereby named LBA1 and LBA2, which descended from the ON1 and NA2 RSV-A genotypes, respectively. RSV-B strains belonged to BA9 genotype except for one BA10. Deduced amino acid sequences depicted several unique substitutions, alteration of glycosylation patterns and the emergence of palivizumab resistance among the Lebanese viruses. The emergence of ON1 and other novel genotypes that are resistant to palivizumab highlights the importance of monitoring RSV globally.

Challenges and opportunities for meningococcal vaccination in the developing world

Meningococcal disease continues to be a life threatening infection with high morbidity and mortality even in appropriately treated patients. Meningococcal vaccination plays a major role in the control of the disease; however, implementing vaccination remains problematic in the developing world. The objective of this review is to identify the challenges facing the use of meningococcal vaccines in the developing world in order to discuss the opportunities and available solutions to improve immunization in these countries. Inadequate epidemiologic information necessary to implement vaccination and financial challenges predominate. Multiple measures are needed to achieve the successful implementation of meningococcal conjugate vaccination programs that protect against circulating serogroups in developing countries including enhanced surveillance systems, financial support and aid through grants, product development partnerships that are the end result of effective collaboration and communication between different interdependent stakeholders to develop affordable vaccines, and demonstration of the cost-effectiveness of new meningococcal vaccines.

Characterization of pharyngeal peristaltic pressure variability during volitional swallowing in healthy individuals

BACKGROUND

Recent technological advances incorporated in high resolution manometry have justifiably heightened interest in manometric evaluation of the pharynx. Despite this interest, from both physiologic and clinical perspective there remain a number of unanswered questions regarding the magnitude of variability of pharyngeal pressure phenomena. Therefore, the aim of the present study was to characterize in healthy individuals the inter-subject and recording-site specific variability of pharyngeal peristaltic pressure phenomena.

METHODS

We studied 32 healthy subjects (age: 21-83 years,20 under 35 years) during dry,5 and 10 mL water swallows ×3. Pharyngeal peristaltic pressures were recorded using a high resolution (HR) manometric system and a catheter assembly with 36 circumferential sensors spaced at 1 cm intervals positioned trans-nasally to traverse the pharynx, UES and proximal esophagus.

KEY RESULTS

Both site-specific pressure data and the Pharyngeal contractile integral (PhCI) showed wide dispersion ranging between values under 50 mm Hg to over 300 mm Hg and 100-600 mm Hg/cm/s,respectively. There was also wide range of dispersion of data for both the standard deviations and the coefficient of variation for all sites (P=.001). The coefficient of variation for PhCI ranged between 0.02 and 0.25 representing data dispersion of 2-25 percent of the mean among subjects (P=.001). Position, age and volume of swallowed fluid did not influence the magnitude of variability.

CONCLUSIONS

Deglutitive Pharyngeal peristalsis generates pressures with significant degree of site-related and inter-subject variability. This variability is not influenced by age, position and volume of swallowed fluid.

AMPA receptor subunits expression and phosphorylation in cingulate cortex in rats following esophageal acid exposure

BACKGROUND

We recently reported an increase in N-methyl-d-aspartate (NMDA) receptor subunit expression and CaMKII-dependent phosphorylation of NR2B in the rostral cingulate cortical (rCC) neurons following esophageal acid exposure in rats. As α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors mediate the fast excitatory transmission and play a critical role in synaptic plasticity, in this study, we investigated the effect of esophageal acid exposure in rats on the expression of AMPA receptor subunits and the involvement of these molecular alterations in acid-induced sensitization of neurons in the anterior cingulate (ACC) and midcingulate (MCC) cortices.

METHODS

In molecular study, we examined GluA1 and GluA2 expression and phosphorylation in membrane preparations and in the isolated postsynaptic densities (PSDs) from rats receiving acute esophageal exposure of either saline (control group) or 0.1 N HCl (experimental group). In electrophysiological study, the effect of selective AMPA receptor (Ca(2+) permeable) antagonist IEM-1460 and CaMKII inhibitor KN-93 was tested on responses of cortical neurons during acid infusion to address the underlying molecular mechanism of acid-induced sensitization.

KEY RESULTS

The acid exposure significantly increased expression of GluA1, pGluA1Ser(831) , and phosphorylated CaMKIIThr(286) , in the cortical membrane preparations. In isolated PSDs, a significant increase in pGluA1Ser(831) was observed in acid-treated rats compared with controls. Microinjection of IEM-1460 or KN-93 near the recording site significantly attenuated acid-induced sensitization of cortical neurons.

CONCLUSIONS & INFERENCES

The underlying mechanism of acid-induced cortical sensitization involves upregulation and CaMKII-mediated phosphorylation of GluA1. These molecular changes of AMPA receptors subunit GluA1 in the cortical neurons might play an important role in acid-induced esophageal hypersensitivity.

The role of the superior laryngeal nerve in esophageal reflexes

The aim of this study was to determine the role of the superior laryngeal nerve (SLN) in the following esophageal reflexes: esophago-upper esophageal sphincter (UES) contractile reflex (EUCR), esophago-lower esophageal sphincter (LES) relaxation reflex (ELIR), secondary peristalsis, pharyngeal swallowing, and belch. Cats (N = 43) were decerebrated and instrumented to record EMG of the cricopharyngeus, thyrohyoideus, geniohyoideus, and cricothyroideus; esophageal pressure; and motility of LES. Reflexes were activated by stimulation of the esophagus via slow balloon or rapid air distension at 1 to 16 cm distal to the UES. Slow balloon distension consistently activated EUCR and ELIR from all areas of the esophagus, but the distal esophagus was more sensitive than the proximal esophagus. Transection of SLN or proximal recurrent laryngeal nerves (RLN) blocked EUCR and ELIR generated from the cervical esophagus. Distal RLN transection blocked EUCR from the distal cervical esophagus. Slow distension of all areas of the esophagus except the most proximal few centimeters activated secondary peristalsis, and SLN transection had no effect on secondary peristalsis. Slow distension of all areas of the esophagus inconsistently activated pharyngeal swallows, and SLN transection blocked generation of pharyngeal swallows from all levels of the esophagus. Slow distension of the esophagus inconsistently activated belching, but rapid air distension consistently activated belching from all areas of the esophagus. SLN transection did not block initiation of belch but blocked one aspect of belch, i.e., inhibition of cricopharyngeus EMG. Vagotomy blocked all aspects of belch generated from all areas of esophagus and blocked all responses of all reflexes not blocked by SLN or RLN transection. In conclusion, the SLN mediates all aspects of the pharyngeal swallow, no portion of the secondary peristalsis, and the EUCR and ELIR generated from the proximal esophagus. Considering that SLN is not a motor nerve for any of these reflexes, the role of the SLN in control of these reflexes is sensory in nature only.

Altered mechanosensitive properties of vagal afferent fibers innervating the stomach following gastric surgery in rats

BACKGROUND AND AIMS

Several types of gastric surgeries have been associated with early satiety, dyspepsia and food intolerances. We aimed to examine alterations in gastric vagal afferents following gastric surgery-fundus ligation.

METHODS

Six week old, male Sprague-Dawley rats underwent chronic ligation (CL) of the fundus. Sham rats underwent abdominal surgery, but without ligation. Another group of rats underwent acute ligation (AL) of the fundus immediately prior to experiments. CL and sham rats were allowed to grow to age 3-4 months. Food intake and weights were recorded post-operatively. Gastric compliance and gastric wall thickness was measured at baseline and during gastric distension (GD). Extracellular recordings were made to examine response characteristics of vagal afferent fibers to GD and to map the stomach receptive field (RF). The morphological structures of afferent terminals in the stomach were examined with retrograde tracings from the nodose ganglion.

RESULTS

The CL group consumed significantly less food and weighed less than sham control. The mean compliance of the CL group was significantly less than control, but higher than the AL group. The spontaneous firing and responses to GD of afferent fibers from the CL rats were significantly higher than AL rats. There was a marked expansion of the gastric RF in the CL rats with significant reorganization and regeneration of intramuscular array (IMA) terminals. There was no difference in total wall or muscle thickness among the groups.

CONCLUSION

CL results in aberrant remodeling of IMAs with expansion of the gastric RF and alters the mechanotransduction properties of vagal afferent fibers. These changes could contribute to altered sensitivity following gastric surgery.

Differential effects of transient receptor vanilloid one (TRPV1) antagonists in acid-induced excitation of esophageal vagal afferent fibers of rats

Gastro-esophageal acid reflux can stimulate esophageal vagal sensory afferents by activating proton-sensitive ion channel transient receptor vanilloid one (TRPV1). The objective of this study was to investigate the response characteristics of vagal afferent fibers of rats to acid (0.1 N HCl) and capsaicin (CAP) following esophagitis and differential effects of two classes of TRPV1 antagonists on responses of vagal afferent fibers. The chronic reflux was induced by ligating the fundus of the stomach and partial constriction of pylorus. Extracellular single fiber recordings were made from the cervical vagal afferent fibers from naive control and fundus-ligated (FL) esophagitis rats. Innervations of fibers were identified to esophageal distension (ED) and subsequently tested to CAP and acid before and after injection of TRPV1 antagonist JYL1421 or AMG9810 (10 micromol/kg i.v.). Seventy-five vagal afferent fibers from 70 rats were identified to ED. Intra-esophageal CAP (0.1 ml of 1 mg/ml) excited 39.5% (17/43, 5/22 from naive and 12/21 from FL rats) fibers. In contrast, i.v. injection of CAP (0.03-0.3 micromol/kg) dose-dependently excited 72% (42/58) fibers. Responses to CAP were significantly greater for fibers from FL rats (n=32) than naive rats (n=25). TRPV1 antagonists JYL1421 and AMG9810 (10 micromol/kg) significantly blocked response to CAP. Intra-esophageal acid infusion stimulated 5/17 (29.4%) fibers from naive rats and 12/28 (42%) from FL rats. Effect of acid was significantly blocked by AMG9810, but not by JYL1421. Results indicate that following esophagitis the number of fibers responsive to CAP and acid is greater than noninflamed esophagus, which may contribute to esophageal hypersensitivity. Acid-induced excitation of vagal sensory afferents can be differentially attenuated by different classes of TRPV1 antagonists. Therefore, TRPV1 antagonists play a key role in attenuation of hypersensitivity following reflux-induced esophagitis. The use of TRPV1 antagonists could be an alternative to the traditional symptoms-based treatment of chronic acid reflux and esophageal hypersensitivity.

Effect of reflux-induced inflammation on transient receptor potential vanilloid one (TRPV1) expression in primary sensory neurons innervating the oesophagus of rats

A possible mechanism of oesophageal hypersensitivity is the acid-induced activation of transient receptor potential vanilloid receptor 1 (TRPV1) in the primary sensory neurons. We investigated TRPV1 expression and its colocalization with substance P (SP) and isolectin B4 (IB4)-positive cells in the thoracic dorsal root ganglia (DRGs) and nodose ganglia (NGs) of rats with reflux-induced oesophagitis (RO). RO was developed by fundus ligation and partial obstruction of the pylorus of Sprague-Dawley rats. Four groups of rats were used; fundus ligated acute (RO 48 h), chronic 7 days (RO 7D), RO 7D + omeprazole (7D + Omz, 40 mg kg(-1), i.p.) and sham-operated controls. Immunohistochemical analysis of TRPV1, SP and IB4 expression were carried out in spinal cord (SC), DRGs and NGs. RO rats exhibited significant inflammation and increase in TRPV1-ir and SP-ir expressions in the SC, DRGs and NGs. The maximum colocalization of TRPV1 and SP was observed in RO 7D rats, but Omz prevented inflammation and over expression of TRPV1 and SP. TRPV1-ir significantly increased in IB4-positive cells in DRGs and SC, but not in the NGs. Results document that acid-induced oesophagitis increases TRPV1 expression in both SP- and IB4-positive sensory neurons. The over expression of TRPV1 may contribute to oesophageal hypersensitivity observed in gastro-oesophageal reflux disease (GORD).

Radial asymmetry of the upper oesophageal sphincter pressure profile: fact or artefact

Radial asymmetry of the upper oesophageal sphincter high-pressure zone (UESHPZ) is an accepted notion based on manometric studies. Our aim was to evaluate the effect of the catheter diameter and configuration on the resting pressure profile of the UES. We studied 14 young (30 +/- 2 years) and 14 healthy elderly volunteers (77 +/- 2 years) using the station pull-through technique. We used a specially designed water perfused manometric assembly that incorporated a proximal round cross-section (4.8 mm) and a distal flat cross-section (4.8 x 1.2 mm). Anterior and posterior manometric sites on the round catheter measured significantly higher pressure values than did the sites oriented laterally at the same level (P < 0.001) in both young and elderly. In contrast, the flat-shaped catheter measured statistically indistinguishable pressures from all four orientations in both age groups. In both young and elderly the anterio-posterior, but not lateral pressures by the round catheter were significantly higher (P < 0.001) than those of the flat catheter. An exaggerated anteriorly and posteriorly oriented pressure may be recorded compared with lateral pressures depending on the diameter and non-conforming shape of the recording catheter with respect to the UES producing the appearance of radial asymmetry in the UESHPZ.

Characteristics of upper oesophageal sphincter and oesophageal body during maturation in healthy human neonates compared with adults

We evaluated the upper oesophageal sphincter (UOS) relationship with oesophageal body during primary peristalsis (PP) sequences in healthy human neonates during maturation and compared with that of healthy adult volunteers. Forty-nine studies were performed using a water perfusion manometry system and a specially designed oesophageal catheter with a UOS sleeve concurrent with submental electromyogram in 31 subjects in supine position (18 preterm neonates, 29.9 +/- 2.5 weeks gestation; four full-term neonates, 39.3 +/- 1.0 weeks gestation; and nine adults, 18-65 years). The preterm neonates were studied longitudinally at 33 and 36 weeks postmenstrual age (PMA) and full-term born at 40 weeks PMA. Data were compared between the groups to recognize the effects of gestation, postnatal age and ageing. We evaluated 403 consecutive spontaneous solitary swallows during maturation (preterm at time-1 vs time-2) and growth (preterm and full-term vs adults) and observed significant (P < 0.05) differences in the basal UOS resting pressure, UOS relaxation characteristics, proximal and distal oesophageal body amplitude, duration, propagation and peristaltic velocity. Characteristics of UOS and PP are well-developed by 33 weeks PMA and undergo further maturation during the postnatal period, and are significantly different from that of adult.

Feasibility and safety of endoscopic evaluation of gastric emptying

BACKGROUND AND STUDY AIMS

Scintigraphy is the currently accepted method for evaluation of gastric emptying. Although quantitative, this method is complicated, time-consuming, and costly. If a simple endoscopic technique was available for those instances when quantification of an emptying abnormality is not needed, the same clinical information could be obtained in less time and with resource savings. Our aims in this study were therefore to assess the technical feasibility, tolerability, and safety of unsedated transnasal esophagogastroscopy (T-EG) as a technique for qualitative assessment of gastric emptying.

METHODS

The study was done in two phases. In the first phase, 18 volunteers (ten men, eight women) underwent T-EG at 4 hours, 5 hours, or 6 hours after ingestion of a standard meal used for scintigraphic evaluation of gastric emptying without radiolabeling. In the second phase, ten volunteers underwent T-EG after scintigraphic imaging had demonstrated complete gastric emptying.

RESULTS

Subjects in both phases tolerated the procedure well and completed the study. In the first phase, 13 of 15 volunteers exhibited complete gastric emptying at 6 hours (87%), while two (13%) revealed some particulate matter in the stomach at that time. In the second phase, one of the ten volunteers exhibited a small amount of solid food residue in the stomach despite documentation of scintigraphic complete emptying.

CONCLUSIONS

Evaluation of gastric emptying by unsedated T-EG is both feasible and safe. In healthy, asymptomatic individuals, complete gastric emptying of solid food may take as long as 6 hours.

Integration of data for gene annotation using the BioMediator system

Gene annotation requires integration of data from multiple sources in order to functionally classify genes. We are using BioMediator, a general purpose data-integration solution, to develop a gene annotation system to automate the process of collecting data from disparate genomic databases. Integration of annotation data from multiple sources into a single format will facilitate use of analytic tools for the proper functional classification of genes.

BioMediator data integration: beyond genomics to neuroscience data

The BioMediator system developed at the University of Washington (UW) provides a theoretical and practical foundation for data integration across diverse biomedical research domains and various data types. In this paper we demonstrate the generalizability of its architecture through its application to the UW Human Brain Project (HBP) for understanding language organization in the brain. We first describe the system architecture and the characteristics of the four data sources developed by the UW HBP. Second we present the process of developing the application prototype for HBP neuroscience researchers posing queries across these semantically and syntactically heterogeneous neurophysiologic data sources. Then we discuss the benefits and potential limitations of the BioMediator system as a general data integration solution for different user groups in genomic and neuroscience research domains.

Response properties of the brainstem neurons of the cat following intra-esophageal acid–pepsin infusion

Studies in humans have documented that acute acid infusion into the esophagus leads to decrease in threshold for sensations to mechanical distension of the esophagus. It is not known whether acid infusion leads to sensitization of brainstem neurons receiving synaptic input from vagal afferent fibers innervating the esophagus. The aim of this study was to investigate the correlation of responses of vagal afferents and brainstem neurons after acute infusion of acid (0.1 N HCl)+pepsin (1 mg/ml) into the esophagus of cats. The vagal afferent fibers (n=20) exhibited pressure-dependent increase in firing to graded esophageal distension (5-80 mm Hg). Infusion of acid+pepsin into the esophagus produced a significant increase in ongoing resting firing of five of 16 fibers (31%) tested. However, their responses to graded esophageal distension did not change when tested 30 min after infusion. Pepsin infusion did not change the resting firing and response to esophageal distension (n=4). Twenty-one brainstem neurons were recorded that responded in an intensity-dependent manner to graded esophageal distension. Responses of 12 excited neurons were tested after intra-esophageal acid+pepsin infusion. Neurons exhibited a decrease in threshold for response to esophageal distension and increase in firing after acid+pepsin infusion. The sensitization of response after intra-esophageal acid remained unaffected after cervical (C1-C2) spinal transection (n=3). Results indicate that the esophageal distension-sensitive neurons in the brainstem exhibit sensitization of response to esophageal distension after acute acid+pepsin exposure. The sensitization of brainstem neurons is possibly initiated by increased spontaneous firing of the vagal afferent fibers to acid+pepsin, but not to sensitized response of vagal distension-sensitive afferent fibers to esophageal distension. Results also indicate that spinal pathway does not contribute to sensitization of brainstem neurons.

Review article: impact of night-time reflux on lifestyle - unrecognized issues in reflux disease

Gastro-oesophageal reflux disease (GERD), manifesting with symptoms including heartburn and regurgitation, affects people during both daytime and nocturnal hours. Night-time GERD has been reported to have a greater impact on a patient's life than daytime GERD due to prolonged oesophageal acid exposure time per reflux episode. To further understand this issue, it is important to implement quality of life (QOL) measures. QOL studies are becoming increasingly important to physicians in making clinical decisions, and generic and disease-specific health-related QOL (HRQL) tools have been developed to measure a wide variety of topics. There are currently no universally accepted guidelines on how to best measure HRQL in GERD patients. It is important to note that these surveys may not yield accurate results because many GERD sufferers may feel that their symptoms are not serious enough to seek treatment. Some surveys include the GERD-HRQL assessment, the Short Form Health Survey (SF-36), and the Gallup survey. When compared with daytime GERD patients, night-time GERD patients may suffer from sleep deprivation, which in turn leads to physical and emotional problems and a poor overall QOL. Studies indicate that the prevalence and impact of night-time heartburn have been underestimated and that adequate treatment of symptoms is often not achieved. In addition, GERD greatly affects work productivity and leads to a significant economic burden on society. Although limited studies are available on the impact of pharmacological treatment on GERD QOL, recent findings indicate that proton pump inhibitors are more effective than H(2)-receptor antagonists for the improvement of overall QOL.

Response properties of antral mechanosensitive afferent fibers and effects of ionotropic glutamate receptor antagonists

The ionotropic glutamate receptors N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are present peripherally in the primary sensory afferent neurons innervating the viscera. Multiple studies have reported roles of glutamate receptors in gastric functions. However, no study has previously shown the direct influence of ionotropic glutamate receptor antagonist on vagal sensory neurons. The objective of this study was to investigate the effects of NMDA and AMPA receptor antagonists on mechanotransduction properties of vagal afferent fibers innervating the rat stomach. Action potentials were recorded from the hyponodal vagus nerve innervating the antrum of the Long-Evans rats. For antral distension (AD), a small latex balloon was inserted into the stomach and positioned in the antrum. The antral contractions were recorded with solid-state probe inserted into the water-filled balloon. Antral units were identified to isovolumic (0.2-1 ml) or isobaric AD (5-60 mm Hg). NMDA and AMPA receptor antagonists were injected in a cumulative fashion (1-100 micromol/kg, i.v.). After the conclusion of experiment, the abdomen was opened and receptive field was mapped by probing the serosa of the stomach. Thirty-two fibers were identified to AD. The receptive fields of 26 fibers were located in the posterior part of the antrum. All fibers exhibited spontaneous firing (mean: 7.00+/-0.97 impulses/s). Twenty fibers exhibited a rhythmic firing that was in phase with antral contractions, whereas 12 fibers exhibited non-rhythmic spontaneous firing unrelated to spontaneous antral contraction. Both groups of fibers exhibited a linear increase in responses to graded isovolumic or isobaric distensions. NMDA (memantine HCl and dizocilpine (MK-801)) and AMPA/kainate (6-cyano-7-nitroquinoxaline 2,3-dione; CNQX) receptor antagonists dose-dependently attenuated the mechanotransduction properties of these fibers to AD. However, competitive NMDA antagonist dl-2-amino-5 phosphopentanoic acid (AP-5) had no effect. The study documents that glutamate receptor antagonists can attenuate responses of gastric vagal sensory afferent fibers innervating the distal stomach, offering insight to potential pharmacological agents in the treatment of gastric disorders.

Defiant dysphagia: small-caliber esophagus and refractory benign esophageal strictures

Among causes of defiant dysphagia, two pose a special challenge for the clinician: the small-caliber esophagus and refractory benign esophageal strictures. The small-caliber esophagus is a major cause of dysphagia for solids in young patients with eosinophilic esophagitis. A smooth, diffusely narrow esophageal lumen can be appreciated by barium esophagography or esophagoscopy. The term "small-caliber esophagus" is preferred over "stricture" because of the absence of cicatrization. A "subtle" small-caliber esophagus may defy detection by barium esophagogram and esophagogastroduodenoscopy. The only evidence to its diagnosis is the endoscopic finding of unusually long rents in the body of the esophagus immediately after esophageal dilation. The ringed esophagus seems to be a variant of the small-caliber esophagus, with the additional endoscopic finding of a variable number of rings (few to numerous) throughout the narrowed esophagus. Classification, diagnosis, and management of small-caliber esophagus are discussed in this review. Refractory esophageal strictures have various causes, including gastroesophageal reflux disease, nasogastric tube placement, mediastinal irradiation, and corrosive ingestion. Treatments used to eliminate or reduce the need for frequent esophageal bougienage include acid-suppressive medical therapy, surgery, intralesional corticosteroid injection, and esophageal self-expandable metal stents.

Resistance of the pulmonary epithelium to movement of buffer ions

Exposure of the apical surfaces of alveolar monolayers to acidic and alkaline solutions has been reported to have little influence on intracellular pH compared with basolateral challenges (Joseph D, Tirmizi O, Zhang X, Crandall ED, and Lubman RL. Am J Physiol Lung Cell Mol Physiol 282: L675-L683, 2002). We have used fluorescent pH indicators and a trifurcated optical bundle to determine whether the apical surfaces are less permeable to ionized buffers than the membranes that separate the vasculature from the tissues in intact rat lungs. In the first set of experiments, the air spaces were filled with perfusate containing FITC-dextran (mol wt 60000) or 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Air space pH fell progressively from 7.4 to 6.61 +/- 0.03 (mean +/- SE, n = 11, air space buffers at 10 mM). Perfusion for 2 min with 2 mM NH4Cl increased air space pH by 0.142 +/- 0.019 unit, without a subsequent acidic overshoot. Infusions of NaHCO3 and sodium acetate reduced pH without a subsequent alkaline overshoot. In the second set of experiments, cellular pH was monitored in air-filled lungs after perfusion with BCECFAM. Injections of NH4Cl caused a biphasic response, with initial alkalinization of the cellular compartment followed by acidification after the NH4Cl was washed from the lungs. Subsequent return of pH to normal was slowed by infusions of 1.0 mM dimethyl amiloride. These studies suggest that lung cells are protected from air space acidification by the impermeability of the apical membranes to buffer ions and that the cells extrude excess H+ through basolateral Na+/H+ exchangers.

Modulation of oesophago-UOS contractile reflex: effect of proximal and distal esophageal distention and swallowing

Upper oesophageal sphincter (UOS) tone is influenced by intraoesophageal pressure events. Our aim was to test the hypothesis that UOS tone is responsive to simultaneous inhibitory and stimulatory signals originating from the oesophagus and compare effect of proximal and distal oesophageal air distention on oesophageal balloon-stimulated UOS contraction. We studied 16 healthy volunteers, ages 19-80 years in two stages. We induced UOS contraction by distending various size balloons intraoesophageally and studied response of contracted UOS to oesophageal air distentions and swallowing. Intraoesophageal injections of 60-ml room air resulted in UOS pressure augmentation (31%), relaxation (64%) and no effect in the remaining 5% of instances. The majority of air injections into the oesophageal segment proximal to the distended balloon were followed by relaxation of the contracted UOS, whereas, the majority of oesophageal air distentions distal to the balloon resulted in augmentation of UOS contraction (P < 0.01). Swallowing resulted in complete relaxation of the UOS. In conclusion, UOS contractile response to oesophageal balloon distention is overridden by further augmentation or relaxation as a result of oesophageal air distention and swallowing. Contractile and inhibitory responses of the contracted UOS to generalized oesophageal distention is region-specific.

Expression array annotation using the BioMediator biological data integration system and the BioConductor analytic platform

This paper presents the implementation of a model for expression array annotation (EAA) using the BioMediator biological data integration system along with BioConductor, an analytic tools platform. The model presented addresses the need for annotation sources identified during BioConductor inverted exclamation mark s development. Annotation provides us with well-curated genomic background knowledge for expression array analysis and interpretation. Annotation requests are constructed and posted to the query interface of the EAA package (the EAA model implemented as a component of BioConductor). The software enumerates all possible annotation paths for queries. These are then transformed to PQL queries and processed by BioMediator. Annotation entities returned from the EAA package answer the annotation request.

Effect of chronic and acute cigarette smoking on the pharyngoglottal closure reflex

BACKGROUND

Injection of water into the pharynx at a threshold volume induces vocal cord adduction--the pharyngoglottal closure reflex (PGCR). This reflex together with other supraoesophageal reflexes may be helpful in preventing aspiration. Cigarette smoking has an adverse affect on the pharyngo-upper oesophageal sphincter contractile reflex and reflexive pharyngeal swallow. The effect of smoking on PGCR has not been studied previously.

AIMS

To elucidate the effect of chronic and acute cigarette smoking on PGCR.

SUBJECTS

We studied 10 chronic smokers and 10 non-smokers before and after real/simulated smoking, respectively.

METHODS

Using concurrent recordings, glottal function was monitored by video endoscopy, swallowing by electromyography, and PGCR was triggered by rapid and slow pharyngeal water injections.

RESULTS

The threshold volume to trigger PGCR during rapid injection was significantly higher in chronic smokers (non-smoker 0.20 (SEM 0.02) ml, smoker 0.36 (0.02) ml; p<0.001). In six of 10 smokers, acute smoking abolished this reflex during slow water injection.

CONCLUSIONS

Smoking adversely affects stimulation of PGCR. This finding may have implications in the development of reflux related respiratory complications in smokers.

A rule driven bi-directional translation system for remapping queries and result sets between a mediated schema and heterogeneous data sources

As the number of online biomedical data sources increases, so too do the number of ways to access such data. The research described herein focuses on creating a data access system that provides bi-directional translation and mapping of data between heterogeneous databases and a mediated schema. Semantic mapping rules stored in a knowledge base are used by our generalized software to convert XML query results obtained from each data source to a common schema representing a single ontology. We apply this approach to the domain of online genetic databases, demonstrating the system's scalability and integratability.

PQL: a declarative query language over dynamic biological schemata

We introduce the PQL query language (PQL) used in the GeneSeek genetic data integration project. PQL incorporates many features of query languages for semi-structured data. To this we add the ability to express metadata constraints like intended semantics and database curation approach. These constraints guide the dynamic generation of potential query plans. This allows a single query to remain relevant even in the presence of source and mediated schemas that are continually evolving, as is often the case in data integration.

Medical treatment of supraesophageal complications of gastroesophageal reflux disease

A growing number of bronchopulmonary, laryngopharyngeal, and oral cavity disorders are suspected of being caused by gastroesophageal refluxate traveling from the esophageal body. Although diagnostic methods have not been developed to positively identify the etiology of these conditions as being related to refluxate, many patients with these supraesophageal manifestations of gastroesophageal reflux disease (SeGERD) respond to empiric antireflux therapy with proton pump inhibitors (PPIs). When used in an appropriate dose (twice daily) and for an appropriate duration (12 weeks or longer), PPIs can be effective in relieving SeGERD symptoms. Economic issues and outcome studies are needed to help further define the role of PPIs in SeGERD.

Unsedated transnasal laryngo-esophagogastroduodenoscopy: an alternative to conventional endoscopy

The introduction, refinement, and subsequent widespread use of flexible fiberoptic endoscopes have revolutionized the diagnosis and management of upper gastrointestinal (GI) disorders. There has been a simultaneous increase in the cost of managing upper GI disorders, which is in part attributed to the high price of endoscopy. Unfortunately, in the current cost-conscious health-care environment, the high cost of endoscopy has resulted in the underuse of this valuable clinical tool. Unsedated transnasal laryngo-esophagogastroduodenoscopy (T-EGD) is a new technique for upper endoscopy that uses an ultrathin endoscope and has a comparable yield to conventional upper endoscopy but obviates the need for conscious sedation because it is better tolerated. Studies have found that T-EGD is a feasible alternative to conventional endoscopy in terms of safety, efficacy, and cost containment. This article reviews these factors, the technique of T-EGD, patient and endoscopist considerations, tissue sampling, and the characteristics of ultrathin endoscopes used for T-EGD.

Esophageal and upper esophageal sphincter motor function in babies

The incidence of concomitant feeding and airway-related disorders is high among premature infants and babies with congenital anomalies. The cause of these disorders is commonly attributed to foregut dysfunction, and the approach to diagnosis and management is largely empiric. Management strategies usually are based on the failure to improve feeding tolerance with advancing maturation and the presence of supraesophageal complications of reflux disease. Very little information exists about the functional development of deglutitive and airway-protective mechanisms in neonates. The purpose of this article is to review the available information on esophageal and upper esophageal sphincter (UES) motor function in human infants. Understanding the maturation of the motor functions of the pharynx-UES and esophagus and related airway-protection responses is essential for determining the pathophysiologic basis of feeding-related airway disorders.

Gender differences in cortical representation of rectal distension in healthy humans

Cerebral cortical processing of information relayed via visceral afferents is poorly understood. We determined and compared cortical activity caused by various levels of rectal distension in healthy male and female subjects. Twenty-eight healthy, young (20-44 yr) volunteer subjects (13 male, 15 female) were studied with a paradigm-driven functional magnetic resonance imaging (fMRI) technique during barostat-controlled rectal distension at perception threshold and 10 mmHg below and above perception threshold. Male subjects showed localized clusters of fMRI activity primarily in the sensory and parietooccipital regions, whereas female subjects also showed activity in the anterior cingulate and insular regions. A progressive increase in maximum percent fMRI signal change and total volume of cortical activity was associated with the intensity of rectal distension pressure in both genders. Regions of cortical activity for below-threshold stimuli showed less substantial signal intensity and volume than responses for threshold and above-threshold stimuli. Volume of cortical activity during rectal distension in women was significantly higher than that for men for all distensions. We conclude that 1) there are substantial differences in female cortical activation topography during rectal distension compared with males; 2) intensity and volume of registered cortical activity due to rectal stimulation are directly related to stimulus strength; and 3) rectal stimulation below perception level is registered in the cerebral cortex.

Mechanisms of reflexes induced by esophageal distension

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.

Post-fundoplication symptoms: the role for endoscopic assessment of fundoplication integrity

BACKGROUND

Fundoplication is now almost exclusively a laparoscopic procedure. The aim of this study was the comparison of the diagnostic usefulness of endoscopy and barium esophagram in the detection of fundoplication abnormalities.

METHODS

Twenty-two patients presented with symptoms post-laparoscopic (Nissen) fundoplication that included dysphagia (14 patients), heartburn (5 patients), dyspepsia (2 patients), and chest pain (1 patient). Barium esophagram and upper endoscopy were performed in all patients and the results were compared. Key features included presence of esophagitis, resistance to endoscope passage, location of the wrap relative to the diaphragmatic hiatus, location of squamocolumnar junction greater than 1 cm proximal to the wrap zone, and the appearance of the wrap (intact, loose, disrupted, or tight).

RESULTS

The key features explained symptoms in 20 of 22 patients. Endoscopy detected twice as many key features as radiography. Disruption of the wrap or excessive proximal location of the squamocolumnar junction proximal to the wrap zone were the most incriminating endoscopic findings. Resistance to endoscope passage was rarely encountered and the esophagram was more accurate in detecting an overly tight wrap.

CONCLUSIONS

Endoscopic evaluation is more accurate than barium esophagram in detecting post-fundoplication abnormalities. The appearance of the fundoplication wrap and an abnormal proximal location of the squamocolumnar junction appear to be major endoscopic clues in diagnosis of post-fundoplication problems.

The new proton pump inhibitor esomeprazole is effective as a maintenance therapy in GERD patients with healed erosive oesophagitis: a 6-month, randomized, double-blind, placebo-controlled study of efficacy and safety

BACKGROUND

Esomeprazole, the S-isomer of omeprazole, is the first proton pump inhibitor to be developed as an optical isomer. In patients with erosive oesophagitis, esomeprazole has produced significantly greater healing rates and improved symptom resolution vs. omeprazole.

AIM

This study assesses the efficacy of esomeprazole for preventing relapse in patients with healed oesophagitis.

METHODS

In this 6-month US multicentre randomized double-blind placebo-controlled trial, 375 Helicobacter pylori-negative patients with endoscopically healed oesophagitis received esomeprazole 40 mg, 20 mg, 10 mg, or placebo once daily. The primary efficacy end-point was maintenance of healing at 6 months. Secondary end-points assessed changes in symptoms, and long-term safety and tolerability.

RESULTS

Significantly (P < 0.001) more patients remained healed with esomeprazole 40 mg (87.9%), 20 mg (78.7%), or 10 mg (54.2%), than with placebo (29.1%). Relapse, when it occurred, was later with esomeprazole. Sustained resolution of heartburn was observed in the 40 mg and 20 mg groups; there was a high correlation between absence of heartburn and maintenance of healing. Adverse effects were mild, infrequent and not significantly different between groups.

CONCLUSIONS

Esomeprazole is effective and well-tolerated in the maintenance of healing of erosive oesophagitis. Esomeprazole 40 mg and 20 mg offer significant clinical benefit to patients.

Choline acetyltransferase activity parallels the pressure gradient in the feline pharyngo-esophageal region

Pressures generated by the pharyngeal constrictor muscles and proximal esophagus involve acetylcholine-induced muscle contractions. We hypothesized that the pharyngo-esophageal pressure gradient is related to choline acetyltransferase activity. In nine anesthetized cats, hypopharyngeal pressure and proximal esophageal pressure were recorded with a solid state transducer assembly. Enzymatic activities in the thyropharyngeus, cricopharyngeus, and proximal esophageal muscles were measured. Hypopharyngeal pressure was higher than the proximal esophagus (p < 0.01), and choline acetyltransferase activity was higher in the cricopharyngeus compared to the proximal esophagus ( p < 0.05). The pressure gradient between the hypopharynx and proximal esophagus may be influenced by the activity of choline acetyltransferase.

Esophageal disorders in the elderly

As the number of elderly in the population increases, decompensation of swallowing and airway protective mechanisms can create an increased health care burden. This article outlines the effect of aging on deglutitive function and esophageal and aerodigestive reflexes. Specific disorders in the elderly are discussed.

Self-expanding metal esophageal stent with anti-reflux mechanism

BACKGROUND

When deployed across the gastroesophageal junction, self-expanding metal esophageal stents can predispose to gastroesophageal reflux. Our aim was to evaluate the efficacy of a self-expanding metal esophageal stent that was modified to prevent gastroesophageal reflux.

METHODS

The polyurethane coating of a metal Z-stent was extended beyond its lower end to form windsock-type valve. The anti-reflux property of this stent was studied in vitro by submerging the stent under water and measuring the pressure required to invert the valve. Esophageal acid exposure time was measured in 5 dogs with a standard and the modified stent placed across the gastroesophageal junction. The modified stent was also placed in 11 patients with cancer of the gastroesophageal junction who were prospectively followed.

RESULTS

The pressure required to invert the valve was directly proportional to the thickness of the valve membrane (48 +/- 0.4 cm water for a 0.0067-inch thick membrane). Esophageal acid exposure time was significantly less with the modified stent as compared with a standard stent (1% +/- 0.3%, 49% +/- 11%, respectively, p = 0.03). Dysphagia score in patients improved from 3.4 +/- 0.1 to 1.1 +/- 0.2 (p < 0.001). Daytime heartburn and regurgitation scores were less than 1 (score 10 = severe). No patient complained of nocturnal reflux symptoms. Karnofsky performance status scale did not improve significantly.

CONCLUSIONS

The efficacy of the modified stent in relieving dysphagia is comparable with a standard stent. It also effectively prevents gastroesophageal reflux.

videoendoscopic evaluation of supraesophageal dysphagia

Oropharyngeal dysphagia is a cause of major morbidity and mortality, particularly in the ever-increasing aged population, following stroke, or after extensive head and neck surgery such as for cancer. Videoendoscopy has become a useful tool in the evaluation and treatment of oropharyngeal dysphagia, and it is particularly suited to patients who may be unable to tolerate videofluoroscopy. This paper reviews the current literature regarding the technique of videoendoscopic evaluation and outlines various indications for its use.

Newer therapies for Gastroesophageal reflux disease: Numb, burn, or stitch?

Preliminary evidence on the efficacy of endoscopically performed interventional techniques for treatment of gastroesophageal reflux disease has emerged in the last year. Three different techniques--radio frequency- induced thermal injury to the gastroesophageal junction, endoscopic plication of gastric folds, and endoscopic implantation of inert polymers into the gastroesophageal junction--have shown promising short-term results. In this review we describe and critically appraise the available published evidence on the efficacy and safety of these techniques. In addition, we discuss clinical and physiologic aspects that are essential for their evaluation and comparison. The need for well-designed controlled clinical trials that assess the long-term efficacy and safety in a wider spectrum of patients is evident, and hopefully such trials are forthcoming. Operator experience and continued evolution in these techniques are likely to be important determinants.

Swallow-related cerebral cortical activity maps are not specific to deglutition

Cortical representation of swallow-related motor tasks has not been systematically investigated. In this study, we elucidated and compared these cortical representations to those of volitional swallow using block-trial and single-trial methods. Fourteen volunteers were studied by functional magnetic resonance imaging. Cortical activation during both swallowing and swallow-related motor tasks that can be performed independent of swallowing, such as jaw clenching, lip pursing, and tongue rolling, was found in four general areas: the anterior cingulate, motor/premotor cortex, insula, and occipital/parietal region corresponding to Brodmann's areas 7, 19, and 31. Regions of activity, volume of activated voxels, and increases in signal intensity were found to be similar between volitional swallow and swallow-related motor tasks. These findings, using both block-trial and single-trial techniques, suggest that cerebral cortical regions activated during swallowing may not be specific to deglutitive function.