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Biomedical subjects

T R DeMeester

Publications and source records attributed to T R DeMeester.

At least 19 recordsLinked to original sources
PubMed1992

Therapy of noncardiac chest pain: is there a role for surgery?

Esophageal distention, motor abnormalities, or exposure of the esophageal mucosa to acidic gastric juice can cause chest pain indistinguishable from that of myocardial ischemia in patients with and without coronary artery disease. In these situations the exact cause of the symptom needs to be established prior to any surgical therapy. An antireflux procedure relieves chest pain in patients with increased esophageal acid exposure more reliably than medical therapy. The best results are obtained in patients in whom a direct correlation of the symptom with reflux episodes can be documented on 24-hour esophageal pH monitoring. Ambulatory 24-hour esophageal motility monitoring shows that esophageal motor disorders are a less frequent cause of noncardiac chest pain than suggested by standard manometry or provocation tests. Furthermore, chest pain episodes in patients with esophageal motor abnormalities are not associated with single contractions of excessively high amplitude or duration. Rather, the symptom appears to be triggered by an increased frequency of simultaneous, multipeaked, and repetitive motor activity. In appropriately selected patients with chest pain and dysphagia secondary to an esophageal motor abnormality, a long esophageal myotomy eliminates the ability of the esophagus to produce these contractions, reduces or eliminates dysphagia, and decreases the frequency and severity of chest pain episodes.

Chest Pain↗
PubMed1992

Effect of Nissen fundoplication on esophageal motor function.

The effect of Nissen fundoplication on the compromised esophageal body function in patients with gastroesophageal reflux disease is poorly understood. Stationary manometry of the distal esophageal body was performed in 50 normal volunteers and compared with that in 40 patients with increased esophageal acid exposure. The studies were performed before and 11 to 68 months (median, 30 months) after successful reflux control and healing of acute mucosal injury with Nissen fundoplication. Before the operation, patients had a lower mean amplitude of contractions, higher prevalence of low amplitude, and interrupted and simultaneous contractions in the distal esophagus compared with normal volunteers. Nissen fundoplication restored the lower esophageal sphincter to normal, increased contraction amplitude, and reduced the prevalence of low-amplitude contractions but did not improve contraction amplitude in patients with a mean amplitude below 35 mm Hg. Fundoplication improves esophageal contraction amplitude but should be performed before the mean contraction amplitude falls below 35 mm Hg.

Circadian Rhythm↗
PubMed1992

Normal 24-hr ambulatory esophageal pH values. Influence of study center, pH electrode, age, and gender.

Although the most sensitive and specific test for diagnosing gastroesophageal reflux disease, normal standards for prolonged esophageal pH monitoring are based on small sample sizes with questions raised about the effects of pH electrode, older age, gender, and methods of data analysis on pH variables. Recently three groups have established normal data bases using similar methodology. Multiple regression and nonparametric analyses showed that the values for the six traditional pH parameters were comparable across study centers. Therefore, the groups were combined for a total study population of 110 healthy subjects (47 men, 63 women, mean age 38 years with a range of 20-84 years). Further nonparametric analyses revealed the following: (1) type of pH electrode (antimony vs glass) is not significantly related to parameters of physiologic acid reflux; (2) age is not independently related to pH parameters; (3) men tend to have more physiologic reflux than women; and (4) older men tend to experience longer episodes of reflux than younger men and women. There was a significant effect of gender and a significant interaction between age and gender on the number of episodes greater than 5 min (P = 0.008). Nearly significant differences were found for percentage of total acid exposure time (P = 0.03), total reflux episodes (P = 0.02), and the longest reflux episode (P = 0.02). We believe these normal esophageal pH values can be used confidently as standards in any laboratory, and consideration should be given to developing separate standards for men and women.

Adult↗
PubMed1992

Foreign body entrapment in the esophagus of healthy subjects--a manometric and scintigraphic study.

Foreign body entrapment and mucosal injury caused by oral medications are increasingly reported to occur in the upper esophagus in apparently normal subjects. We performed esophageal manometry in 40 normal volunteers to determine whether a unique motility pattern in the upper third of the esophagus predisposes to entrapment of foreign bodies at this site; 18 normal volunteers also had transit scintigraphy of a gelatin capsule filled with a radionuclide. The esophageal body was divided into five consecutive segments starting proximally, with each segment corresponding to 20% of the total length. Amplitude, slope, and velocity of the esophageal contraction were markedly decreased in the second segment compared with the other segments. Entrapment and dissolution of a gelatin capsule occurred in 39% of volunteers in the proximal esophagus correlating to the second segment, i.e., the segment with the lowest amplitude, slope, and velocity of esophageal contractions. The observation that wet swallows have greater amplitudes (P less than 0.01) and steeper slopes (P less than 0.05) than dry swallows explains why the occurrence of pill entrapment was reduced when taken with sufficient water. However, even with a water chaser of 120 mL, pill entrapment occurred at the second segment of the esophagus in 1 of 18 volunteers. The observed motility pattern in the proximal esophagus provides a better explanation for the entrapment of foreign bodies at this site than compression of the esophagus by the left main stem bronchus, aortic arch, or left atrium as suggested by other investigators.

Adult↗
PubMed1992

Effect of duodenal switch procedure on gastric acid production, intragastric pH, gastric emptying, and gastrointestinal hormones.

The duodenal switch operation preserves the pylorus and the proximal 3 to 7 cm of duodenum in continuity with the stomach while diverting pancreaticobiliary secretions. We compared it with the Roux-en-Y without vagotomy or antrectomy in 12 dogs with innervated gastric pouches. Acid secretion was inhibited between tests using ranitidine in the Roux-en-Y group only, but two of the six dogs still developed stomal ulcers and the remainder showed stomal hyperemia. This may be due to a significant increase in gastric acid output after Roux-en-Y, but gastric emptying and plasma gastrin, cholecystokinin, secretin, gastric inhibitory polypeptide, peptide YY, and neurotensin were similar after both procedures. In 12 patients and a further 6 dogs, the duodenal switch caused no significant change in the intragastric pH environment as assessed by intragastric pH monitoring. The duodenal switch is a suitable procedure for pancreaticobiliary diversion.

Anastomosis, Roux-en-Y↗
PubMed1992

Concentration of refluxed acid and esophageal mucosal injury.

The hallmark of gastroesophageal reflux disease (GERD) is an increase in esophageal exposure to gastric juice. This exposure can result in complications such as esophagitis, stricture, and Barrett's esophagus. The aim of this study is to determine if there are specific pH exposure patterns that are associated with the development of these complications. The 24-hour esophageal pH data for 50 normal subjects and 154 patients with proven GERD were analyzed for time spent at different pH intervals. Increased esophageal acid exposure at a given interval occurred when the cumulative time of exposure exceeded the 95th percentile of that measured in the 50 normal subjects for that interval. The greatest prevalence of mucosal damage was found in the those patients with increased esophageal exposure to pH 0 to 2, corresponding to the known pKa of pepsin. This exposure was not related to a hypersecretory state. In addition, mucosal injury was associated with an increased esophageal exposure to pH 7 to 8. We conclude that mucosal injury in patients with GERD is related to the exposure time to gastric juice with a pH of less than 2 or greater than 7.

Adult↗
PubMed1992

Complications of gastroesophageal reflux disease. Role of the lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and duodenogastric reflux.

The factors contributing to the development of esophageal mucosal injury in gastroesophageal reflux disease (GERD) are unclear. The lower esophageal sphincter, esophageal acid and acid/alkaline exposure, and the presence of excessive duodenogastric reflux (DGR) was evaluated in 205 consecutive patients with GERD and various degrees of mucosal injury (no mucosal injury, n = 92; esophagitis, n = 66; stricture, n = 19; Barrett's esophagus, n = 28). Manometry and 24-hour esophageal pH monitoring showed that the prevalence and severity of esophageal mucosal injury was higher in patients with a mechanically defective lower esophageal sphincter (p less than 0.01) or increased esophageal acid/alkaline exposure (p less than 0.01) as compared with those with a normal sphincter or only increased esophageal acid exposure. Complications of GERD were particularly frequent and severe in patients who had a combination of a defective sphincter and increased esophageal acid/alkaline exposure (p less than 0.01). Combined esophageal and gastric pH monitoring showed that esophageal alkaline exposure was increased only in GERD patients with DGR (p less than 0.05) and that DGR was more frequent in GERD patients with a stricture or Barrett's esophagus. A mechanically defective lower esophageal sphincter and reflux of acid gastric juice contaminated with duodenal contents therefore appear to be the most important determinants for the development of mucosal injury in GERD. This explains why some patients fail medical therapy and supports the surgical reconstruction of the defective sphincter as the most effective therapy.

Adolescent↗
PubMed1992

Surgery and the management of peripheral lung tumors adherent to the parietal pleura.

Among 37 patients with peripheral T3 lung lesions, preoperative clinical and imaging evidence was suggestive of T3 disease in 28 and of T2 disease in nine. Intraoperatively, the T2 designation was changed to T3 on the basis of adherence of the tumor to the parietal pleura. All had mediastinoscopy followed by resection and complete lymph node dissection. There were 17 lobectomies and 20 pneumonectomies. The chest wall was resected in continuity with the lung in 21 patients, and in 16 only an extrapleural resection was done. Follow-up was completed in all patients (range 2 to 14 years, median 7 years). The 5-year actuarial survival rate for all patients was 30%. As expected, the presence of lymph node metastasis affected the 5-year actuarial survival rate: N0 = 41%; N1 = 29%, and N2 = 0%. Histologic examination of the resected specimen confirmed a T3 lesion in 30 patients. The tumor was removed completely in 100% of patients whose chest wall was resected in continuity with the lung but in only 31% in whom an extrapleural resection was done. In the absence of lymph node metastasis, the 5-year survival rate of patients after en bloc resection of the chest wall was 50% compared with 33% for those with extrapleural resection (p less than 0.05). The finding of a peripheral lung tumor adherent to the parietal pleura indicates, in most instances, extension through the parietal pleura. When tumor is firmly adherent to the parietal pleura, an en bloc resection of the chest wall rather than an extrapleural dissection should be performed. This assures complete tumor removal and improves the probability of long-term survival.

Carcinoma, Non-Small-Cell Lung↗
PubMed1992

Physiologic assessment and surgical management of diffuse esophageal spasm.

The physiologic abnormalities and management of patients with diffuse esophageal spasm are controversial. We evaluated the symptomatic and functional results of surgical therapy in 19 patients with diffuse esophageal spasm who were incapacitated with dysphagia and chest pain and unresponsive to conservative management. A long esophageal myotomy with an antireflux procedure was performed in 15 patients, and four patients with multiple previous esophageal procedures had an esophagectomy. Eleven patients had increased esophageal exposure to gastric juice on preoperative 24-hour esophageal pH monitoring. The severity of dysphagia, chest pain, regurgitation, and heartburn was scored on a scale of 0 to 3 before and a mean of 24 months (range 8 months to 13 years) after the operation. After myotomy, each of these symptoms and the overall symptom score improved significantly (p < 0.01). The improvement in the symptom scores in the patients who had esophagectomy were comparable with the improvement after myotomy. On self-assessment, 90% of the patients would have the operation again if again faced with the decision. Standard and ambulatory 24-hour manometry showed a significant reduction in the amplitude of the esophageal body contractions, a decrease in the frequency of simultaneous contractions, and the elimination of multi-peaked waves after the myotomy. Despite the addition of an antireflux procedure, lower esophageal sphincter pressure, overall length, and abdominal length were reduced markedly after the myotomy. This was associated with persistent or emerging heartburn or regurgitation in four patients. These data indicate that a long esophageal myotomy is a valid treatment alternative in appropriately selected patients with diffuse esophageal spasm. Esophagectomy and colon interposition is the procedure of choice in patients with multiple previously failed myotomies.

Esophageal Spasm, Diffuse↗
PubMed1992

Clinical value of endoscopy and histology in the diagnosis of duodenogastric reflux disease.

BACKGROUND: The endoscopic observation of a bile lake in the stomach, antral gastritis, or ulcerations and the histologic finding of foveolar hyperplasia or chronic gastritis have been implicated as indicators of excessive duodenogastric reflux. The accuracy of these criteria was evaluated in 135 patients with nonspecific symptoms in the foregut suggestive of duodenogastric reflux and no evidence for alcohol- or drug-induced gastric mucosal injury. METHODS: The presence of excessive duodenogastric reflux was objectively determined by means of both gastric pH monitoring and cholescintigraphy with cholecystokinin stimulation. RESULTS: Endoscopy showed antral gastritis in 67 patients, gastric ulcers in 19, and a bile lake in the stomach in 39 (total of 135 patients). Of 90 patients who underwent biopsy, histologic findings showed foveolar hyperplasia in 26, chronic gastritis in 19, and active gastritis in 28 patients. The latter condition was associated with Helicobacter pylori in 20 patients. When gastric pH monitoring, cholescintigraphy, or both were used as "gold standard," the sensitivity, specificity, accuracy, and positive predictive value of endoscopic and histologic criteria to diagnose the presence of excessive duodenogastric reflux were poor except in the rare case of active gastritis but no Helicobacter pylori. CONCLUSIONS: The presence of duodenogastric reflux disease cannot be accurately diagnosed with endoscopic or histologic criteria. The diagnosis should be made with objective techniques, particularly when surgical therapy is considered.

Biopsy↗
PubMed1992

Ambulatory 24-h esophageal pH monitoring: normal values, optimal thresholds, specificity, sensitivity, and reproducibility.

Ambulatory 24-h esophageal pH monitoring is increasing in popularity as the means to measure esophageal exposure to gastric juice and document the presence of gastroesophageal reflux disease, particularly before surgical therapy. Normal values for pH exposure were obtained from 50 asymptomatic healthy subjects. Receiver operating characteristic curves constructed from another 25 asymptomatic healthy subjects and 25 selected patients with other markers of increased esophageal acid exposure showed that a composite score and the percent total time pH less than 4 provide the most efficient interpretation of the test with a sensitivity of 96%, a specificity of 100% and an accuracy of 98% for the composite score, and a sensitivity, specificity, and accuracy of 96% for the percent total time pH less than 4. Repeat monitoring of healthy volunteers and symptomatic subjects in the inpatient and outpatient environment showed no significant difference, with the exception that the number of reflux episodes was significantly greater during the outpatient recording in volunteers. This did not affect the clinical accuracy of the test. Esophageal pH probes were well tolerated, but caused belching and coughing during the early part of the monitored period. We conclude that computerized ambulatory 24-h esophageal pH monitoring in the outpatient setting provides accurate and reproducible results.

Adult↗
PubMed1992

Effect of alprazolam (Xanax) on esophageal motility and acid reflux.

Recent studies suggest that psychotropic drugs may help the symptoms associated with spastic esophageal motor disorders. However, the physiologic effects of central nervous system depression (a side effect of such therapy) on esophageal function is not known. Therefore, we studied the effect of alprazolam (Xanax), a popular new benzodiazepine anxiolytic, in 10 healthy volunteers, using a randomized, placebo-controlled design. Stationary esophageal motility, 24-h pH monitoring, and 24-h ambulatory motility monitoring was done while on placebo or one tablet (0.25 mg) of alprazolam taken three times a day. Alprazolam had no significant effect on lower esophageal sphincter pressure or motility in the esophagus. Upper esophageal sphincter pressure, however, was significantly decreased. What is more important, one-third of the healthy volunteers had abnormal amounts of nocturnal acid reflux during the alprazolam phase of the study. This effect was probably due to alprazolam-induced central nervous system depression interfering with normal nocturnal acid clearance mechanisms triggered by arousal from sleep.

Adult↗
PubMed1992

Nonobstructive dysphagia in gastroesophageal reflux disease: a study with combined ambulatory pH and motility monitoring.

Nonobstructive dysphagia is a common symptom of gastroesophageal reflux disease, and may be present in up to 45% of patients. To elucidate the mechanism of dysphagia, stationary and ambulatory motility studies were performed in 10 controls and 27 patients with gastroesophageal reflux disease. Sixteen patients had nonobstructive dysphagia and 11 had no dysphagia. During stationary studies, there was essentially no difference in esophageal body motility among all the groups. Lower esophageal sphincter manometry was similar in patients with or without dysphagia. On ambulatory motility, about 40% of contractions in the body of the esophagus were simultaneous in the supine position in controls and both groups of patients. The rate of simultaneous contractions decreased in the upright position and at mealtimes in controls and in patients without dysphagia, but not in those with dysphagia. This resulted in a higher percentage (38%) of intraprandial simultaneous wave activity in patients with dysphagia than in those without dysphagia (23%) or in controls (13%) (p less than 0.05). Patients with reflux disease who suffer from nonobstructive dysphagia therefore have a motility disorder measurable on ambulatory motility studies which results in an increased percentage of nonperistaltic (simultaneous wave) activity during mealtimes.

Adult↗
PubMed1992

Duodenoesophageal reflux and the development of esophageal adenocarcinoma in rats.

BACKGROUND: The carcinogenic effect of duodenoesophageal reflux, gastroesophageal reflux, and nitrosamines was studied in the rat esophagus. METHODS: Twenty male Sprague-Dawley rats underwent esophagogastroplasty to produce gastroesophageal reflux and 60 underwent duodenoesophageal anastomosis to produce duodenoesophageal reflux. Forty-three animals underwent no operation and acted as controls. Carcinogens known to produce squamous tumors in the rat esophagus (2,6-dimethylnitrosomorpholine [DMNM] or methyl-n-amylnitrosamine [MNAN]) were tested in each group. RESULTS: The rate of squamous carcinoma was 25% for rats with DMNM alone, 30% for rats with MNAN alone, and 20% for rats with induced gastroesophageal reflux plus DMNM. The rate of malignant change rose to 80% in rats with induced duodenoesophageal reflux and DMNM and 67% with duodenoesophageal reflux and MNAN. With duodenoesophageal reflux, 50% of tumors were adenocarcinoma, in contrast to 100% squamous differentiation of tumors in rats given the carcinogens with esophagogastroplasty or no operation. CONCLUSION: The presence of duodenoesophageal reflux increased the frequency and changed the histologic type of esophageal cancer in nitrosamine-treated rats. This indicates that duodenoesophageal reflux plays a role in the development of esophageal adenocarcinoma.

Adenocarcinoma↗
PubMed1992

Immunosuppression in patients with Barrett's esophagus.

BACKGROUND: Patients with Barrett's esophagus have a higher incidence of esophageal cancer than has the general population. Local tissue injury and exposure to carcinogens presumably play a role in malignant transformation, but the possibility of altered host immune surveillance must also be considered. METHODS: The level of immunoreactivity was investigated in six healthy control subjects; 14 patients with gastroesophageal reflux, seven with and seven without esophagitis; and nine patients with Barrett's esophagus. Parameters studied were (1) T-cell and B-cell function with mitogen-stimulated lymphocyte blastogenesis, (2) immunosuppressive properties of autologous serum, and (3) interleukin-2 production by peripheral blood mononuclear cells. Nutritional status as a possible cause for immunosuppression was assessed by measurement of serum albumin, transferrin, and prealbumin. RESULTS: Patients with Barrett's esophagus had a significant suppression of all T-cell (p less than 0.01) and B-cell function (p less than 0.01) and interleukin-2 production (p less than 0.001) when they were compared to the controls. Interleukin-2 production was also reduced significantly compared to that in patients with gastroesophageal reflux with and without esophagitis (p less than 0.05). No differences were observed in serum immunosuppression or nutritional factors. CONCLUSIONS: Although the immunosuppression observed in the patients with Barrett's esophagus was milder than that found in other immunocompromised states, it may be sufficient to encourage the malignant transformation of Barrett's mucosa.

Adult↗
PubMed1992

Neuropeptide release from the isolated, perfused, lower esophageal sphincter region of the rabbit and the effect of vasoactive intestinal peptide on the sphincter.

BACKGROUND: The aim was to evaluate the isolated, vascularly perfused, lower esophageal sphincter (LES) as a model for investigating the functional role of neuropeptides such as vasoactive intestinal peptide (VIP). METHODS: At laparotomy the LES was removed along with the distal esophagus, stomach, and left gastric artery and vein. The LES area, isolated from the body of the stomach by a custom-made clamp, was perfused with oxygenated Krebs-Ringer bicarbonate solution (pH 7.4, 38 degrees C) via the left gastric artery. The LES pressure was monitored continuously with a custom-made Dent sleeve catheter. LES pressure and release of neuropeptides were investigated after carbachol and VIP were administered alone or in combination. VIP, calcitonin gene-related peptide (CGRP), and somatostatin were measured in the venous perfusate collected from the left gastric vein. RESULTS: LES tone and contraction frequency were similarly increased by 10 and 100 nmol/L carbachol (increment, 4.0 +/- 0.26 mm Hg with 10 nmol/L carbachol; p less than 0.0003). Perfusion with 10 nmol/L VIP decreased basal tone and completely abolished the contraction induced by 100 nmol/L carbachol. VIP, CGRP, and somatostatin were released from the LES in response to 10 nmol/L carbachol (VIP rose from 55 +/- 13 to 179 +/- 24 pmol/L, CGRP, from 114 +/- 30 to 239 +/- 33 pmol/L, and somatostatin from 15 +/- 2 to 27 +/- 4 pmol/L; all p less than 0.001). CONCLUSIONS: These findings support a role for VIP in the inhibitory reflex of the LES but suggest that other neuropeptides may also be involved. The isolated, perfused LES provides a new tool for investigating neuropeptide interactions.

Animals↗