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Biomedical subjects

R Shaker

Publications and source records attributed to R Shaker.

At least 55 records · Page 3Linked to original sources
PubMed2000

Life after antireflux surgery.

Laparoscopic fundoplication technique has become the operative modality of choice for antireflux surgery. An increasing number of patients and physicians have enthusiastically embraced this "minimally-invasive" technologic development for treatment of gastroesophageal reflux disease (GERD). However, laparoscopic fundoplication has been frequently advertised as the therapeutic solution for all GERD patients. Subsequently, the number and severity of complications resulting from laparoscopic surgery--often performed indiscriminately--has increased dramatically. This article reviews the efficacy of the laparoscopic fundoplication operation for GERD based on current, relatively short-term reports from centers specializing in this treatment modality. The majority of these reports are very positive. Unfortunately, the results of fundoplication operations performed by community surgeons are unknown. There are a number of disturbing factors relating to laparoscopic treatment for GERD that should raise a red flag of caution to the medical community, particularly primary-care physicians and their patients. The central portion of this report devotes itself to discussing the problems associated with this new minimally-invasive technique for fundoplication operations. These problems include the selectivity of current reports on outcomes of the laparascopic fundoplication operation and the lack of uniform data acquisition associated with these postoperative studies. The technical difficulties of the laparascopic fundoplication surgery are discussed, and the need for operator expertise and appreciation of esophageal physiology and anatomy are stressed. Finally, the long-term durability of the fundoplication wrap is questioned and the morbidity associated with the operation--particularly dysphagia--is addressed. In the final segment, the complications encountered after laparoscopic fundoplication operations are detailed and the techniques for evaluating the symptomatic postfundoplication patient are discussed. Laparoscopic fundoplication operation is good therapy in an appropriate clinical setting when performed by a well-trained and experienced surgeon. However, the operation should not be first-line therapy for the majority of GERD patients. An esophagus disabled by an inappropriate or dysfunctional fundoplication wrap is a terrible price to pay for control of acid reflux.

Esophagoscopy↗
PubMed2000

An overview of the upper esophageal sphincter.

The anatomy and physiology of the upper esophageal sphincter (UES) are complex. Much progress has been made over the past few years in our understanding this important sphincter. The closing muscles of the UES include the inferior pharyngeal sphincter, the cricopharyngeus (CP), and the cervical esophagus. The CP is composed of two parts, which may have different functions. The CP is innervated by the pharyngeal plexus and the recurrent laryngeal nerve. Tone of the UES is probably generated by numerous reflexes rather than by specific tone-generating circuitry. The major tone-generating muscle is the CP, which is highly elastic and produces more active tension the more it is stretched. The UES opens by relaxation of the closing muscles, traction by muscles attached to the hyoid bone and thyroid cartilage, and pulsion of the bolus. The various muscles of the UES behave differently during its many dynamic states, so that similar functions are accomplished by different muscles.

Esophagogastric Junction↗
PubMed2000

Pharyngeal dysphagia in postesophagectomy patients: correlation with deglutitive biomechanics.

BACKGROUND: Because of the transient nature of pharyngeal phase dysphagia, posttranshiatal esophagectomy patients provide a model for studying the correlation of dysphagic symptoms and aspiration with deglutitive biomechanics. METHODS: We studied 8 transhiatal esophagectomy patients (age range, 51 to 78 years) and 8 normal age-matched controls in upright position using lateral and anteroposterior (AP) projection videofluoroscopy during three 5 mL barium swallows. RESULTS: The maximum upper esophageal sphincter (UES) AP diameter and maximum anterior excursion of the hyoid bone in patients with transhiatal esophagectomy who experienced aspiration (6.2+/-0.6 and 9.0+/-2.0 mm, respectively) were significantly smaller than those of age-matched normal controls (9.4+/-0.7 and 17.0+/-1.0 mm, respectively). Resolution of aspiration was associated with a significant increase in AP diameter of the UES as well as anterior and superior excursion of the hyoid bone (p<0.05). CONCLUSIONS: Dysphagic symptoms and aspiration in posttranshiatal esophagectomy patients are associated with significant abnormalities of deglutitive biomechanics. Improvement in deglutitive biomechanics is associated with resolution of dysphagic symptoms as well as postdeglutitive aspiration in these patients.

Aged↗
PubMed2000

Supraesophageal complications of gastroesophageal reflux.

Supraesophageal complications of GERD have become more commonly recognized or suspected by physicians. However, the direct association between these complications and GERD has often been difficult, if not impossible, to establish. Furthermore, the majority of patients with suspected supraesophageal complications of GERD do not have either the characteristic symptoms of heartburn and regurgitation or the definitive findings of esophageal inflammation, which would help reinforce the suspicion of a connection between the supraesophageal complications and GERD. Frequent acid reflux has been shown in patients with various bron-chopulmonary, laryngopharyngeal, or oral cavity disorders. GERD is one of the most common gastrointestinal complaints in the population. It is possible that the supraesophageal problems and acid reflux are mutually independent disorders that occur in the same person. The suspected mechanisms of GERD-related supraesophageal complications appear to be directed through two pathways: by a vagal reflex between the esophagus and tracheobronchial tree triggered by acid reflux or by microaspiration that causes contact damage to mucosal surfaces. The most useful diagnostic modality available to the clinician to aid in the diagnosis of supraesophageal GERD complications is the ambulatory pH recording technique. However, the sensitivity and specificity of this test for recording esophageal or pharyngeal acid reflux events has been critically challenged. Despite the many clinical studies that support the theory that GER has a role in suspected supraesophageal complications, only 1 long-term prospective controlled study of a large group of patients with asthma has shown the positive effects of the elimination of acid reflux. With the focus now on "outcomes medicine," there is a serious need for appropriately designed, controlled studies to answer the many questions surrounding a cause-and-effect association between acid reflux and supraesophageal disorders. Because of the lack of convincing proof between acid reflux and suspected supraesophageal complications, the physician must resort to an intent-to-treat strategy as both a primary therapy and a diagnostic trial. High-dose PPI therapy for prolonged periods is the recognized conservative therapy. Operative therapy (i.e., fundoplication operation) is the procedure of choice when overt regurgitation occurs or when medical therapy, although successful, is not practical for long periods. Controlled, well-designed clinical trials and more sophisticated techniques to measure and quantify acid reflux are crucial in the future to help determine which patients with suspected supraesophageal complications actually have acid reflux as a primary cause. The medical community needs to be alerted to the possibility of an association between GERD and supra-esophageal complications so that patients with a GERD-related complication will be recognized and effectively treated.

Adult↗
PubMed2000

Does open access endoscopy close the door to an adequately informed patient?

BACKGROUND: The use of open access endoscopy is increasing. Its effect on the adequacy of patient informed consent, procedure acceptance and the impact on subsequent communication/transfer of procedure results to the patient have not been evaluated. The aim of our study was to compare the extent of preknowledge of procedures and test explanation, patient medical complexity, information transfer and overall patient satisfaction between a patient group referred for outpatient open access endoscopy versus a patient group from a gastrointestinal (GI) subspecialty clinic. METHODS: Information was obtained from all patients presenting for outpatient upper and lower endoscopy by using a 1-page questionnaire. Patients from the two groups who had an outpatient upper/lower endoscopic procedure were contacted by phone after the procedure to obtain information with a standardized questionnaire. RESULTS: The open access patients reported receiving significantly less information to help them identify the procedure (p < 0.01) and less explanation concerning the nature of the procedure than the group of patients referred from the subspecialty clinic (p < 0.005). There was no difference between the two groups in satisfaction scores for examinations performed under conscious sedation. For flexible sigmoidoscopy without sedation, however, the GI clinic patient group were more satisfied with their procedure. The majority of patients, regardless of access, were more likely to receive endoscopic results from a gastroenterologist than the referring physician. Furthermore, the patients in the GI clinic group who underwent colonoscopy felt significantly better at follow-up. CONCLUSIONS: Patients undergoing open access procedures are less likely to be properly informed about their endoscopic procedure. Our results indicate that with open access endoscopy, a defined mechanism needs to be in place for communication of endoscopic results to the patient.

Adult↗
PubMed2000

Deterioration of the pharyngo-UES contractile reflex in the elderly.

OBJECTIVES/HYPOTHESIS: Deterioration of aerodigestive tract reflexes such as the esophagoglottal and pharyngoglottal closure reflexes and pharyngeal swallow has been documented in the elderly. However, the effect of aging on the contractile response of the upper esophageal sphincter (UES) to pharyngeal water stimulation has not been studied. The aim of this study was to characterize the pharyngo-UES reflex in the healthy elderly. METHODS: We studied nine healthy elderly (77 +/- 1 y [SD]; four men, five women) and nine healthy young volunteers (26 +/- 2 y [SD]; four men, five women). AUES sleeve sensor was used to measure the pressure. We tested pharyngeal stimulation induced by rapid pulse and slow continuous injection of water. RESULTS: The volume of water required to stimulate the pharyngo-UES contractile reflex by rapid pulse injection in the elderly (0.5 +/- 34 0.1 mL) was significantly higher than that in the young (0.1 +/- 0.02 mL) (P < .05). In contrast to young subjects, there was no pressure increase in resting UES pressure observed in the elderly for continuous pharyngeal water infusion. In both young and elderly, the threshold volume for the pharyngo-UES contractile reflex was significantly lower than that for pharyngeal swallows. CONCLUSIONS: The pharyngo-UES contractile reflex deteriorates with aging. This deterioration is primarily due to abnormalities of the afferent limb of the reflex.

Aged↗
PubMed2000

Effect of ageing on the upper and lower oesophageal sphincters.

OBJECTIVE: To determine the effect of ageing on length and resting pressure of the upper and lower oesophageal sphincters (UOSs, LOSs). BACKGROUND: The effectiveness of upper and lower oesophageal sphincters (UOSs and LOSs, respectively) in the control of retrograde trans-sphincteric flow is influenced by sphincteric pressure and length. METHODS: Nine young and nine elderly healthy volunteers were studied. Resting UOS and LOS pressures were measured by sleeve devices and lengths were measured by the station pull-through technique. RESULTS: The length of the UOS high pressure zone in the elderly (2.1 +/- 0.7 cm posterior; 1.9 +/- 0.1 cm anterior) was significantly shorter than that of the young (2.9 +/- 0.1 cm posterior; 3.1 +/- 0.2 cm anterior) (P< 0.01). Resting UOS pressure in the elderly (42 +/- 5 mmHg) was significantly lower than that of the young (62 +/- 7 mmHg) (P< 0.05). The intersphincteric length of the oesophagus in the elderly (21 +/- 0.2 cm) was similar to that of the young (21 +/- 0.4 cm). Total length of the LOS high pressure zone in the young (4.0 +/- 0.1 cm) was similar to that of the elderly (4.1 +/- 0.1 cm). LOS resting pressure was similar between young and elderly subjects (17 +/- 5 mmHg and 15 +/- 3 mmHg, respectively). CONCLUSIONS: Ageing affects the UOS and LOS differently. With regard to resting pressure and length, ageing weakens the UOS, but has no significant effect on the LOS.

Adult↗
PubMed2000

Disruption of primary and secondary esophageal peristalsis by afferent stimulation.

Recent studies have shown that afferent signals originating from the pharynx inhibit progression of primary esophageal peristalsis. Our aim was to further elucidate the effect of esophageal and pharyngeal afferent stimulation on primary and secondary esophageal peristalsis. We studied the effect of esophageal air distension and pharyngeal water stimulation on progression of primary and secondary peristalsis in nine healthy volunteers aged 27 +/- 2 yr (4 men, 5 women). At a threshold volume, rapid injection of water into the pharynx, directed posteriorly, resulted in complete halt of the progressing secondary and primary esophageal peristalses in both the proximal and distal esophagus. The threshold volume of injected water for inducing inhibition was similar for secondary (0.6 +/- 0.2 ml) and primary (0.5 +/- 0.1 ml) esophageal peristalsis. Progression of primary peristalsis induced by a dry swallow and secondary peristalsis induced by intraesophageal air distension were completely inhibited by intraesophageal injection of 15 +/- 2 ml of air in 70% and 75% of the trials, respectively. We conclude that afferent signals induced by esophageal air distension and pharyngeal water stimulation inhibit propagation of both primary and secondary esophageal peristalsis, suggesting a shared neural control mechanism for these types of peristalsis.

Adult↗
PubMed2000

Upper esophageal sphincter function during gastroesophageal reflux events revisited.

Upper esophageal sphincter (UES) function during gastroesophageal reflux events is not completely elucidated because previous studies addressing this issue yielded conflicting results. We reexamined the UES pressure response to intraluminal esophageal pressure and pH changes induced by reflux events. We studied 14 healthy, asymptomatic volunteers (age 49 +/- 6 yr) and 7 gastroesophageal reflux disease patients (age 48 +/- 5 yr). UES pressure, intraesophageal pressure, and pH were monitored at the distal, middle, and proximal esophagus concurrently in the supine position 1 h before and 2 h after a 1,000-calorie meal. A total of 321 reflux events were identified by the development of abrupt reflux-induced intraesophageal pressure increase (IPI); 285 events occurred in patients and 36 in control subjects. In control subjects 33 of 36 and in patients 252 of 285 IPI events were associated with a pH drop. Among patients and control subjects, 99% and 100%, respectively, of all IPI events irrespective of pH drop were associated with abrupt increase in UES pressure (34 +/- 2 and 27 +/- 6 mmHg, respectively). The average percentage of maximum UES pressure increase over prereflux values ranged between 66% and 96% (control subjects) and 34% and 122% (patients). IPIs induced by both acidic and nonacidic reflux events evoke strong UES contractile responses.

Acids↗
PubMed1999

Sequence-tagged connectors: a sequence approach to mapping and scanning the human genome.

The sequence-tagged connector (STC) strategy proposes to generate sequence tags densely scattered (every 3.3 kilobases) across the human genome by arraying 450,000 bacterial artificial chromosomes (BACs) with randomly cleaved inserts, sequencing both ends of each, and preparing a restriction enzyme fingerprint of each. The STC resource, containing end sequences, fingerprints, and arrayed BACs, creates a map where the interrelationships of the individual BAC clones are resolved through their STCs as overlapping BAC clones are sequenced. Once a seed or initiation BAC clone is sequenced, the minimum overlapping 5' and 3' BAC clones can be identified computationally and sequenced. By reiterating this "sequence-then-map by computer analysis against the STC database" strategy, a minimum tiling path of clones can be sequenced at a rate that is primarily limited by the sequencing throughput of individual genome centers. As of February 1999, we had deposited, together with The Institute for Genomic Research (TIGR), into GenBank 314,000 STCs ( approximately 135 megabases), or 4.5% of human genomic DNA. This genome survey reveals numerous genes, genome-wide repeats, simple sequence repeats (potential genetic markers), and CpG islands (potential gene initiation sites). It also illustrates the power of the STC strategy for creating minimum tiling paths of BAC clones for large-scale genomic sequencing. Because the STC resource permits the easy integration of genetic, physical, gene, and sequence maps for chromosomes, it will be a powerful tool for the initial analysis of the human genome and other complex genomes.

Chromosome Mapping↗
PubMed1999

Unsedated transnasal EGD: an alternative approach to conventional esophagogastroduodenoscopy for documenting Helicobacter pylori eradication.

BACKGROUND: The aim of this study was to assess the yield of antral biopsies performed via unsedated transnasal esophagogastroduodenoscopy, a technique that does not require conscious sedation with its concomitant costs and complications, for documentation of Helicobacter pylori eradication. METHODS: Nineteen patients who were previously CLO test positive on conventional esophagogastroduodenoscopy and subsequently treated for H pylori infection were enrolled. The subjects had not received antibiotic therapy in the prior month and had no prior gastric surgery. By using a GIF-N30 fiberoptic endoscope and a tiny cup biopsy forceps (1.8 mm diameter), unsedated transnasal endoscopy was performed and antral biopsy specimens were taken for a CLO test, histologic analysis (Dieterle stain), and tissue culture. On the same day, the subjects underwent a carbon 13-labeled area urea breath test. All subjects completed a visual analog scale, rating the acceptability of the unsedated transnasal examination and the previous sedated conventional esophagogastroduodenoscopy. RESULTS: There was no statistically significant difference between the results of the CLO tests (5/19 positive) versus the 13C-urea breath test (4/19 positive) (p = 0.96), the CLO tests versus histologic findings (5/19 positive) (p = 0.71), or the 13C-urea breath test versus histologic findings (p = 0.96). All tissue culture results were negative. The overall acceptability of unsedated transnasal esophagogastroduodenoscopy was similar to that of sedated conventional esophagogastroduodenoscopy. CONCLUSION: Unsedated transnasal esophagogastroduodenoscopy, a technique that eliminates the costs and complications associated with conscious sedation, is a feasible and accurate alternative to conventional esophagogastroduodenoscopy when documentation of H pylori eradication and confirmation of gastric ulcer healing are both indicated.

Adult↗
PubMed1999

Pharyngeal pH monitoring in patients with posterior laryngitis.

OBJECTIVE: To evaluate the diagnostic value of 3-site 24-hour ambulatory pH monitoring in patients with posterior laryngitis (PL) and the prevalence of esophageal abnormalities in this patient group. METHODS: Twenty patients with PL and 17 healthy volunteers were studied as controls. Control subjects had transnasal esophagogastroduodenoscopy (T-EGD) and ambulatory pH monitoring. Patients underwent T-EGD, ambulatory pH monitoring, and barium esophagram. RESULTS: T-EGD documented no abnormality in controls. Esophagitis was present in 2 PL patients, and hiatal hernia in 3. Ambulatory pH monitoring showed that 15 PL patients and 2 controls exhibited pharyngeal acid reflux. Barium esophagram documented gastroesophageal reflux in 5 PL patients. However, none of these barium reflux events reached the pharynx. All PL patients with barium esophagram evidence of gastroesophageal reflux also showed pharyngeal acid reflux by pH monitoring. CONCLUSION: Pharyngeal acid reflux is more prevalent in patients with PL than in healthy controls. Patients with PL infrequently have esophageal sequelae of reflux disease. Ambulatory 24-hour simultaneous 3-site pharyngoesophageal pH monitoring detects gastroesophagopharyngeal acid reflux events in most patients with PL.

Adolescent↗
PubMed1999

Pharyngeal acid reflux in patients with single and multiple otolaryngologic disorders.

OBJECTIVE: This study was designed to determine the prevalence and characteristics of pharyngeal acid reflux (PAR) events in single and multiple otolaryngologic disorders. METHODS: Sixty-seven patients with otolaryngologic symptoms and objective findings and 34 healthy control subjects were studied with an ambulatory 24-hour, 3-site pharyngoesophageal pH monitoring technique. Otolaryngologic diagnosis included isolated posterior laryngitis (PL) in 28 patients, isolated chronic rhinosinusitis (SIN) in 12, combined PL and SIN (PL+SIN) in 6, PL plus laryngotracheal stenosis (PL+LTS) in 12, and PL plus vocal cord nodules (PL+VCN) in 9. RESULTS: PAR events were documented in 68% of patients with PL, 34% of patients with SIN, 67% of patients with PL+SIN, 67% of patients with PL+LTS, 78% of patients with PL+VCN, and 21% of controls. The prevalence of PAR events in patients with isolated PL as well as those with PL combined with other disorders was significantly higher than that in patients without PL and that in controls. As a group, patients with PL had a greater number of PAR events and acid exposure time than other patients and controls. Distal and proximal esophageal reflux parameters were not significantly different among groups. CONCLUSIONS: The prevalence of PAR is significantly higher in patients with isolated PL compared to patients with other isolated otolaryngologic disorders and in controls. The prevalence of PAR in isolated otolaryngologic disorders other than PL is similar to that in healthy controls. The prevalence of PAR is significantly higher in patients with both PL and other otolaryngologic disorders than in controls and in patients with isolated otolaryngologic disorders.

Adolescent↗