Effect of thyrotropin-releasing hormone on immune functions of peripheral blood mononuclear cells

The tripeptide thyrotropin-releasing hormone (TRH) works as a hypothalamic hormone, but is found also outside the brain in intrinsic nerve fibers of the gastrointestinal tract. There is evidence that TRH modulates the activity of immunocompetent cells, although there are only very few data on TRH-mediated immune effector functions. Since we could recently show that TRH inhibits monocyte activities we were also interested in other possible TRH modulated immune functions. Peripheral blood mononuclear cells (PBMC) from ten healthy subjects were cultured for 7 days and pulsed with 0.125 and 0.250 microgram/ml Pokeweed mitogen (PWM). 10(-12) to 10(-6) M TRH was added simultaneously with PWM. Lymphocyte proliferation [(3H]thymidine incorporation), interferon-gamma (IFN-gamma) activity (RIA) and immunoglobulin activities (IgG, IgM, IgA; ELISA) were determined in the supernatants. We could demonstrate a TRH-dependent decrease in PWM-pulsed IgG activity with significant (alpha = 0.05) values at 10(-8) and 10(-10) M (-29 +/- 6%/-16 +/- 3% for PWM 0.125 microgram/ml and -17 +/- 9%/-11 +/- 9% for PWM 0.250 microgram/ml). This inhibitory effect could be abolished by an anti-TRH antiserum. There was no TRH effect on IgM and IgA activities, IFN-gamma activity and lymphocyte proliferation compared with the PWM stimulated values alone. The described TRH effect on the polyclonal IgG response by PBMC gives further evidence for a functional link between the immune system and the endocrine system, although its underlying mechanism is not yet clear.

Endoscopic ultrasonography in the evaluation of colon and rectal disease

Endosonography of the colon has until recently been limited to examination of the rectum. Rigid and flexible instruments are currently available which allow for detailed images of the rectal wall. Comparative studies suggest that endosonography may be more accurate than computed tomography in the preoperative staging of rectal carcinoma. Recently, an ultrasound colonoscope has been developed which allows for visual examination, biopsy, and endosonography throughout the colon. Experience with this technique is limited and its role in the evaluation of colonic disease has not yet been determined. Further comparative trials are needed to more fully define the role of endosonography in the diagnosis of colorectal disease.

[Colon endosonography. Initial experiences in clinical use]

For the first time we report about a new diagnostic technique, the endoluminal ultrasound of the colon. It enables us to examine the whole colon by an ultrasound endoscope. The ultrasound frequency of the instrument (XCF-UM2, Olympus Optical/Aloka, Japan) is 7.5 MHz, the roundview is approximately 320 degrees. The mean advantage is the combination of endoscopic inspection including biopsy and endoluminal ultrasound. First clinical experience was gained at a total of 27 examinations. It was possible to demonstrate the normal colonic wall (n = 10) in the entire large bowel, neighbouring organs could be visualized clearly and reproducibly in most cases. Pathologic findings (four carcinomas, eight polyps, five anastomoses) were correctly diagnosed by endosonography with a sensitivity of 100% and a specificity of 96%. In two cases the histopathologic work-up of the resected specimens confirmed the ultrasonographic diagnosis of malignancy, while the endoscopic biopsy indicated benign wall lesions. This suggests that endosonography may be superior to histological diagnosis by biopsy in some cases.

Evaluation of inter- and intramolecular primary structure homologies of interferons by a Monte Carlo method

Using Sellers TT algorithm, primary structure repeats have been described for interferon (IFN)-alpha, -beta 1, and gamma. To reevaluate these results and to extend them to IFN-beta 2 (interleukin-6), a modified algorithm was developed that uses a metric to define the "best" partial homology of two peptide sequences and to compare it to those detected in random permutations of the peptide. Using this approach, the known structural homologies of IFN-alpha with IFN-beta 1 and of human (Hu) IFN-gamma with murine (Mu) IFN-gamma were identified correctly. However, the primary structure repeats in the amino acid sequences of IFN-alpha, -beta 1, and -gamma turned out to be no better than those detectable in random permutations of these sequences. These results were confirmed using a different, nonlinear metric. A previously used approach to demonstrate significance was shown to produce false-positive results. No significant primary structure homologies were detected among IFN-beta 1, -beta 2, and -gamma. In contrast to the amino acid sequence analysis, the DNA sequence of HuIFN-beta 1 contained a significant repeat that had no significant counterpart in MuIFN-beta or in IFN-alpha. In conclusion, some previously reported results obtained with Sellers TT algorithm on amino acid sequences are easily explained as random similarities, and it is therefore strongly recommended that a method like ours should be used to control significance.

[Electromagnetic shockwave lithotripsy of gallstones. Preliminary clinical experiences]

75 applications of extracorporeal electromagnetically produced shock-waves were performed on 40 patients with symptomatic gallbladder stones (27 women and 13 men; mean age 43.5 [25-69] years). The patients had up to three stones each, with a maximal diameter of 35 mm. Computed tomography revealed partial calcification of the stones in nine patients. Stone fragmentation succeeded in all patients. Two weeks after lithotripsy two patients were free of stone. Maximal fragment diameter, as measured by ultrasound, was less than 6 mm in 19 patients, 6-10 mm in 14, and 11-15 mm in five. At reexamination of 24 patients three months later, three additional patients were free of stone by ultrasound. No significant side effects were noted during the first 30 days after the procedure. But during further observation mild pancreatitis developed in two, while in one choledochal concrements caused obstructive jaundice which necessitated endoscopic papillotomy. These results demonstrate the effectiveness of this method of fragmenting gall-bladder stones.

Effect of substance P on immunoglobulin and interferon-gamma secretion by cultured human duodenal mucosa

Recently, we have demonstrated a substance P (SP)-dependent modulation of in vitro IgM and interferon-gamma (IFN-gamma) secretion by human peripheral blood mononuclear cells, as well as lymphokine activities in supernatants of cultured duodenal mucosa. Therefore we investigated other local immunoregulatory effects of SP. Duodenal biopsies of 7 healthy subjects were cultured with Pokeweed mitogen (PWM, 1 microgram/ml) for 4 days at 37 degrees C in 1 ml medium each. SP was added in concentrations ranging from 10(-12)M to 10(-6)M on day 1. Fresh media with fresh PWM were added every day. IgG, IgM, IgA (ELISA) and IFN-gamma (RIA) were determined in the culture supernatants. Values were referred to 5 mg biopsy weight and expressed as % change in basal PWM pulsed secretion, or as units/ml. 10(-6) M and 10(-12) M SP increased secretion of all immunoglobulin isotypes. Compared to controls, 10(-6) M and 10(-12) M SP led to an increase in IgM secretion of up to 73 +/- 23% and 41 +/- 32% and to an increase in IgA secretion up to 96 +/- 35% and 25 +/- 33%, respectively (alpha = 0.02 for both isotypes at 10(-6) M). 10(-12) M to 10(-6) M SP led to a significant dose-dependent increase in IFN-gamma secretion from 7.08 +/- 1.65 up to 21.8 +/- 12.6 units/ml/5 mg. The maximum effect could be seen on culture days 3 and 4. We were able to demonstrate for the first time that SP stimulates PWM pulsed immunoglobulin and IFN-gamma secretion by human duodenal immunocompetent cells. These results support the hypothesis of local neuropeptidergic-immune interactions.

A new ultrasonic probe for endosonographic imaging of the upper GI-tract. Preliminary observations

A new ultrasonic probe (7.5 MHz, diameter 3.7 mm) was used in vitro in 3 gastric resection specimens and in vivo in 12 patients in an attempt to visualize normal and pathological wall structure of the esophagus, stomach and duodenum via the working channel of a gastroscope, and of the biliary tract via the percutaneous approach. In 5 of these patients conventional endosonography was performed. The probe visualizes the normal layer structure and pathological lesions of the upper GI-tract wall, since it can be accurately positioned at the structure of interest under visual control; water is instilled into the hollow organs to improve transmission of the ultrasound beam. Intra- and transmural changes such as blood vessels in the wall of the esophagus and stomach in portal hypertension, or gastric and esophageal tumors were demonstrated. The important advantage of the probe is that it can be used in stenosed or narrowed hollow organs, where conventional endosonography fails. However, the depth of penetration of the ultrasonic beam (10-15 mm) and circumferential imaging of the gastric wall are still inferior to those of conventional endoscopic ultrasound. As the focus distance of the ultrasound probe to the biliary ducts is too small, visualization of the biliary system is incomplete. Technical improvements could make this new probe an irreplacable diagnostic tool in the future.

[Time factors in endoscopic studies. A survey in West Germany]

In order to obtain representative data for the orientation of personal requirements in endoscopic units, 650 hospitals in the FRG were asked to have an exact look at the times they needed for endoscopic procedures during an period of 14 days. 25% of the contacted hospitals answered to this request and thus the times required for more than 14,000 endoscopic procedures for both, doctors and medical staff, could be analysed. Results revealed that most of the sophisticated procedures such as colonoscopy, ERCP (especially when they included therapeutic endoscopical methods) varied largely in time. This was caused by different factors such as the patient dependent variables, and the course of the procedure including observation of safety and hygiene standards. Average values of times needed for endoscopic procedures were as follows (time in minutes): (Table: see text). The data given above might be of value for the estimation of actual personal and time requirements in endoscopic units.

A 19-year-old female with blue rubber bleb nevus syndrome. Endoscopic laser photocoagulation and surgical resection of gastrointestinal angiomata

A case of a blue rubber bleb nevus syndrome in a 19-year-old female patient with multiple cutaneous and gastrointestinal hemangiomata is described. Recurrent GI bleeding resulted in severe chronic anemia, which was successfully treated by endoscopic laser photocoagulation and surgical resection. Both forms of therapy had to be repeated 4 years later, the patient having been well in the meantime. This combined endoscopic and surgical approach might also improve the survival of patients with severe GI hemorrhage due to blue rubber bleb nevus syndrome.

Leukotrienes C4 and D4 potentiate acid production by isolated rat parietal cells

The effects of leukotrienes (LTs) B4, C4, and D4 on acid production by enriched (80%-85%) rat parietal cells were investigated. Acid production was indirectly measured by [14C]aminopyrine uptake into the cells. Leukotriene B4 (10(-10)-10(-6) mol/L) had no effect on basal or prestimulated [14C]aminopyrine uptake. Leukotriene C4 and LTD4 (10(-10)-10(-6) mol/L) also did not change basal acid production but potentiated prestimulated [14C]aminopyrine uptake. Maximal effects were observed with 1 x 10(-7) mol/L LTC4 or with 3 x 10(-7) mol/L LTD4. At these concentrations LTC4 and LTD4 induced the indicated increases above the responses to the following prestimulants (= 100%): 10(-4) mol/L histamine (71% and 74%, respectively), 10(-5) mol/L forskolin (54% and 106%), 10(-4) mol/L dibutyryl cyclic adenosine monophosphate (34% and 81%), and 10(-4) mol/L carbamylcholine (160% and 116%). Yet, adenosine triphosphate (2.5-5 x 10(-3) mol/L)-induced [14C]aminopyrine uptake in digitonin-permeabilized parietal cells was not further increased by LTC4 or LTD4. At 10(-5) mol/L the selective LTD4 antagonist L-660,711 (MK-571) reduced the effect of 3 x 10(-7) mol/L LTD4 by 74% but had no effect on the potentiation by LTC4. We conclude that the sulfidopeptide LTs C4 and D4, but not LTB4, exert a direct effect on rat parietal cells, and that this effect seems to be mediated by separate specific receptors. Leukotriene C4 and LTD4 potentiate prestimulated H+ formation by interacting with an intracellular mechanism that is commonly activated upon occupation of histamine H2- as well as muscarinic receptors, and that is also activated by the postreceptor stimuli forskolin and dibutyryl cyclic adenosine monophosphate; yet, this mechanism seems to be localized proximal to the H+,K+-adenosine triphosphatase.

Effect of CCK on insulin, glucagon, and pancreatic polypeptide levels in humans

The present study was designed to determine the effect of low doses of cholecystokinin (CCK) on insulin, glucagon, and pancreatic polypeptide (PP) secretion in the basal state and during prestimulation with amino acids and glucose alone or in combination. Two different amino acid solutions available for use in humans were employed. Aminosteril-N-Hepa was better for the imitation of the so-called "insulinogenic" amino acids while Aminoplasmal L-10 gave more comparable plasma levels of the "glucagonogenic" amino acids as observed after a protein-rich meal. In healthy volunteers, low-dose CCK infusion [Thr28,Nle31-CCK 25-33 (CCK-9)] in stepwise increasing doses of 5, 10, and 20 pmol/kg/h had no effect on basal, glucose-, or amino acid-stimulated insulin release. During the combination of Aminoplasmal + glucose, there was a small and only transient increase of plasma insulin levels that did not occur during Aminosteril + glucose. CCK did not alter glucagon levels either during i.v. amino acids alone or during combination of amino acids with glucose. CCK-stimulated PP levels in the basal state in a dose-dependent manner. This effect was enhanced during i.v. Aminosteril but not i.v. Aminoplasmal infusion. During i.v. glucose, the effect of CCK on PP levels was abolished. In conclusion, the present data demonstrate that CCK is unlikely to be a stimulus of insulin and glucagon secretion in the basal state and also during prestimulation by fairly physiological quantities of amino acid mixtures. On the other hand, the present data support a physiological role of CCK in the regulation of PP secretion.

Effects of CCK-8 in combination with natural or synthetic secretin on amylase, lipase, trypsin, and chymotrypsin secretion in rats

In the present study, we examined the interaction between CCK-8 and natural or synthetic secretin on pancreatic enzyme secretion. On anaesthetized rats, a proximal duodenal segment was continuously perfused with saline and amylase, lipase, trypsin, and chymotrypsin were determined in the perfusate. Neither during iv saline nor during iv secretin (natural or synthetic) at doses of 0.01, 0.05, or 0.1 CU/kg/h, any of the four enzymes changed significantly from basal values over a period of 100 min. Iv CCK-8 at stepwise increasing doses of 5, 10, and 20 pmol/kg/h elicited a significant increase of all four enzymes at the medium dose, with a further increase of amylase and trypsin, but not lipase and chymotrypsin at 20 pmol/kg/h. The addition of secretin at all 3 doses potentiated CCK-induced trypsin output. The effects of natural secretin were more pronounced than those of the synthetic peptide. Secretin significantly increased amylase secretion over basal at the lowest dose of CCK-8 (5 pmol/kg/h) that by itself had no effect on amylase release. Only the higher doses of natural but not synthetic secretin augmented lipase secretion during the lowest dose of CCK-8. Both forms of secretin had no further stimulatory effect on CCK-induced chymotrypsin secretion. The present data demonstrate that, first, in rats a potentiation of CCK-8-induced enzyme secretion by low doses of secretin is different for the four enzymes, which suggests a differential regulatory action of these two intestinal hormones on pancreatic enzyme release. Second, the different effects of natural secretin may represent those of contaminants suggesting that only synthetic secretin should be employed in future studies of this peptide on pancreatic enzyme secretion.

Effect of gastrin-releasing peptide (GRP1-27), neuromedin-C (GRP18-27), and neuromedin-B on gastrin and somatostatin secretion from the rat stomach

In the present study the effects of gastrin-releasing peptide (GRP1-27), its C-terminal decapeptide neuromedin-C (GRP18-27) and the related peptide neuromedin-B were examined on the secretion of gastrin and somatostatin-like immunoreactivity (SLI) from the isolated perfused rat stomach at intraluminal pH 7 or pH 2. GRP1-27 and GRP18-27 stimulated gastrin secretion equally effective at concentrations of 10(-10), 10(-9), 10(-8), 10(-7) and 10(6)M at luminal pH 7. In addition neuromedin-B was tested at 10(-11), 10(-10), 10(-8) and 10(-6)M and it increased gastrin release similar to equimolar doses of GRP18-27. At luminal pH 2 GRP1-27 stimulated gastrin secretion at 10(-9), 10(-8), 10(-7) and 10(-6)M while GRP18-27 was only effective at 10(-8) and 10(-7)M. Neuromedin-B elicited a gastrin increase at 10(-8)M similar to GRP18-27 and also at 10(-6)M. All three peptides had no significant effect on SLI release at luminal pH 7. At luminal pH 2 GRP1-27 at 10(-9)M and 10(-6)M and GRP18-27 and neuromedin-B at 10(-10)M elicited a significant stimulation of SLI secretion. These data demonstrate that all three bombesin-like peptides GRP1-27, GRP18-27 and neuromedin-B can stimulate gastrin release at either a neutral or an acidic luminal pH, while SLI release is affected only at an acidic intragastric milieu. This suggests that all three forms of bombesin-like peptides are good candidates for the peptidergic regulation of gastrin release in the rat stomach, while their role in somatostatin release seems to be more restricted.

Self-expanding biliary stents: preliminary clinical experience

Nine self-expanding metallic stents were implanted in 7 patients to relieve biliary obstruction. One patient had a benign stricture and 6 patients had malignant stenoses. The stent was inserted percutaneously on a 7 F delivery catheter in 6 patients. Endoscopic transpapillary implantation was performed in one patient. After release the stent expanded to a diameter of 8-10 mm. The correct position was checked by fluoroscopy and cholangiography. In addition, percutaneous cholangioscopy was carried out in 6 patients. No complications were observed within 30 days. Clinical improvement was seen in all patients. After a mean follow-up period of 11 weeks (range: 3-17) 6 of the 7 patients are still alive with no evidence of biliary reobstruction. One patient died of disseminated malignancy. The initial results are promising. The wide-bore diameter, the macroporous configuration and the small surface area of the implanted self-expanding stents would seem to be associated with lower rates of infection, clogging and migration as compared with conventional endoprostheses. Further trials are warranted to determine the future role of self-expanding stents in biliary obstruction.

The effects of intraduodenal bile acid administration on biliary secretion of ionized calcium and carbonate in man

The importance of calcium in gallstone formation is increasingly recognized. Calcium carbonate is an important constituent of gallbladder stones and may be present in the nidus of cholesterol stones. Secondary deposition of calcium carbonate on the surface of cholesterol gallstones is an important reason for failure of oral bile acid dissolution therapy. We sought to determine the effects of bile acids on the crystallization conditions of calcium carbonate in bile. We studied 18 patients with choledocholithiasis with a percutaneous or endoscopically placed catheter high in the biliary tree. Samples of bile in the basal state and following replacement of the bile acid pool with cholic acid, chenodeoxycholic acid and ursodeoxycholic acid were analyzed for total calcium, ionized calcium, bicarbonate and carbonate, and the saturation index for calcium carbonate was calculated. Hepatic bile in the basal state was supersaturated with calcium carbonate. Total calcium concentrations rose linearly with rising bile acid concentrations but ionized calcium was maintained in a relatively narrow range. These data are consistent with an important role for bile acids in binding calcium. Extrapolation of the linear regressions between bile acid concentration and calcium concentrations suggested that in the absence of bile acids, biliary calcium concentrations are in passive equilibrium with plasma. Chenodeoxycholic acid and ursodeoxycholic acid caused a bicarbonate-rich choleresis and significantly augmented the saturation index for calcium carbonate, whereas cholic acid caused no change. In contrast with animal models, the apparent choleretic activity of cholic acid, chenodeoxycholic acid and ursodeoxycholic acid was similar, and no hyper-choleresis was observed with ursodeoxycholic acid. Chenodeoxycholic acid and ursodeoxycholic acid therefore increase the thermodynamic possibility for calcium carbonate precipitation.

Role of amino acids in stimulation of postprandial insulin, glucagon, and pancreatic polypeptide in humans

Protein-rich meals stimulate secretion of insulin, glucagon, and pancreatic polypeptide (PP) from the endocrine pancreas. On the one hand, this is due to increased levels of circulating amino acids, and, on the other, neural and/or endocrine factors can contribute to activation of islet cell function. The present study was designed to determine, first, pancreatic endocrine function and postprandial amino acid levels after a protein and a protein-carbohydrate meal and second, insulin, glucagon, and PP levels during infusion of amino acid mixtures that imitate the postprandial amino acid pattern. In healthy volunteers the ingestion of a protein-rich meal (300 g tenderloin steak) elicited within 1 h an increase of virtually all amino acids by 20-400 mumol/L above basal values. The infusion of two different amino acid solutions available for use in humans showed that Aminosteril-N-Hepa (AS) was better for the imitation of the so-called "insulinogenic" amino acids while Aminoplasmal L-10 (AP) gave more comparable plasma levels of the "glucagonogenic" amino acids. Both solutions were not able to imitate the postprandial amino acid pattern completely. With regard to insulin levels, both solutions gave a comparable increase, while AP but not AS stimulated glucagon and PP levels. This suggests that circulating amino acids may be responsible for 60% of the postprandial insulin response after a protein meal, while their contribution to glucagon release can only be roughly estimated at 30-60%. The contribution of circulating nutrients to the greater insulin response after the protein-carbohydrate meal was comparable (60%), while the attenuated glucagon response can be ascribed almost completely to the effect of circulating nutrients. In conclusion, the present data demonstrate that the composition of amino acid mixtures is as yet not ideal for a complete imitation of the postprandial amino acid pattern. The insulin, glucagon, and PP response depends on the amino acid mixtures and accordingly the respective plasma amino acid concentrations obtained during infusion studies. The adequate imitation of plasma amino acid levels is of critical importance for the evaluation of absorbed and circulating amino acid effects in the postprandial state.

Circulating amino acids and pancreatic endocrine function after ingestion of a protein-rich meal in obese subjects

We measured plasma amino acid together with insulin, glucagon, pancreatic polypeptide (PP), and glucose concentrations after the ingestion of a protein meal in lean and obese subjects. The basal plasma amino acid levels were similar in both groups. The postprandial increase in the plasma amino acid levels in the obese subjects was only 15-50% of that in the lean subjects. The mean basal and peak postprandial plasma insulin levels were significantly higher (72 and 165 pmol/L) in the obese group than in the lean group (36 and 115 pmol/L; P less than 0.05-0.01). The postprandial rise in plasma glucagon was largely attenuated in the obese subjects, and there was no difference in plasma PP and glucose levels in the 2 groups. To further evaluate the role of circulating amino acids on pancreatic endocrine function in obese and lean subjects, an amino acid mixture consisting of 15 amino acids was infused iv. During the infusion the plasma amino acid levels were comparable in both groups. Plasma insulin rose by 36 +/- 7 (+/- SE) pmol/L (5 +/- 1 microU/mL) in the lean and 129 +/- 22 pmol/L (18 +/- 3 microU/mL) in the obese subjects, whereas plasma glucagon, PP, and glucose levels were similar in both groups. In view of the 3.6-fold greater insulin responses in the obese subjects, it is likely that circulating amino acids contribute to their hyperinsulinemia in spite of the reduced postprandial rise of amino acids in this group (50-85%). Thus, under physiological conditions amino acids have to be considered as an important regulatory component of postprandial insulin release in obese subjects.

Omega-conotoxin GVIA specifically blocks neuronal mechanisms in rat ileum

Omega Conotoxin is a peptide venom of the marine snail Conus geographus which has been postulated as a neural specific calcium channel blocker in several systems. In the present study in rat ileum strips omega-conotoxin GVIA specifically blocked neuronal responses evoked by electrical field stimulation in a dose-dependent manner, but did not block responses induced by carbachol or direct depolarization with KCl. On the other hand the dyhydropyridine calcium channel blocker nitrendipine (10(-7) M) showed no specificity and blocked electrical field stimulation as well as carbachol- and KCl-induced contractions. This indicates that contractions of intestinal smooth muscle which can be blocked by dihydropyridine calcium channel blockers or Ca2+-free medium are not reduced by the neurotoxin omega-conotoxin. Omega-conotoxin caused even a little increase of the responses elicited by depolarisation with KCL. Omega-conotoxin blocked however neural mediated contractions which might suggest that it interacts with a distinct neuronal calcium channel and, in addition to tetrodotoxin, could provide a useful pharmacological tool to discriminate between muscular and neural sites of action of excitatory or inhibitory agents.

Endoscopic ultrasonography in esophageal diseases

Endoscopic ultrasonography (EUS) was performed prospectively in 38 patients with various esophageal disorders. Twenty-four had a histologically proven carcinoma and EUS was done to assess its ability in preoperative staging. In 9 of 24 patients (37.5%), tumor stenosis could be passed with the endoscope and EUS preoperative findings regarding tumor extension and the presence of enlarged periesophageal lymph nodes were confirmed in those operated on (n = 4). In five patients with achalasia, a periesophageal tumor was reliably excluded by EUS. In one of four patients with Barrett's esophagus, EUS demonstrated a small (less than 1 cm) carcinoma that could not be visualized with any conventional technique. For differentiation of cancer recurrence after operation from periesophageal scar tissue EUS-guided transmural biopsies are needed. Our experience shows that at the present time EUS is the most reliable method to demonstrate small (less than or equal to 1 cm) intra- and extramural esophageal lesions and that it should therefore be applied early in the work-up of patients with dysphagia.