Central 5-HT neurotransmission modulates weight loss following gastric bypass surgery in obese individuals.

The cerebral serotonin (5-HT) system shows distinct differences in obesity compared with the lean state. Here, it was investigated whether serotonergic neurotransmission in obesity is a stable trait or changes in association with weight loss induced by Roux-in-Y gastric bypass (RYGB) surgery. In vivo cerebral 5-HT2A receptor and 5-HT transporter binding was determined by positron emission tomography in 21 obese [four men; body mass index (BMI), 40.1 ± 4.1 kg/m(2)] and 10 lean (three men; BMI, 24.6 ± 1.5 kg/m(2)) individuals. Fourteen obese individuals were re-examined after RYGB surgery. First, it was confirmed that obese individuals have higher cerebral 5-HT2A receptor binding than lean individuals. Importantly, we found that higher presurgical 5-HT2A receptor binding predicted greater weight loss after RYGB and that the change in 5-HT2A receptor and 5-HT transporter binding correlated with weight loss after RYGB. The changes in the 5-HT neurotransmission before and after RYGB are in accordance with a model wherein the cerebral extracellular 5-HT level modulates the regulation of body weight. Our findings support that the cerebral 5-HT system contributes both to establish the obese condition and to regulate the body weight in response to RYGB.

Molecular pathology in vulnerable carotid plaques: correlation with [18]-fluorodeoxyglucose positron emission tomography (FDG-PET).

OBJECTIVES: Atherosclerosis is recognised as an inflammatory disease, and new diagnostic tools are warranted to evaluate plaque inflammatory activity and risk of cardiovascular events. We investigated [18]-fluorodeoxyglucose (FDG) uptake in vulnerable carotid plaques visualised by positron emission tomography (PET). Uptake was correlated to quantitative gene expression of known markers of inflammation and plaque vulnerability. METHODS: Ten patients with recent transient ischaemic attack and carotid artery stenosis (>50%) underwent combined FDG-PET and computed tomography angiography (CTA) the day before carotid endarterectomy. Plaque mRNA expression of the inflammatory cytokine interleukin 18 (IL-18), the macrophage-specific marker CD68 and the two proteinases, Cathepsin K and matrix metalloproteinase 9 (MMP-9), were quantified using real-time quantitative polymerase chain reaction. RESULTS: Consistent up-regulation of CD68 (3.8-fold+/-0.9; mean+/-standard error), Cathepsin K (2.1-fold+/-0.5), MMP-9 (122-fold+/-65) and IL-18 (3.4-fold+/-0.7) were found in the plaques, compared to reference-artery specimens. The FDG uptake by plaques was strongly correlated with CD68 gene expression (r=0.71, P=0.02). Any correlations with Cathepsin K, MMP-9 or IL-18 gene expression were weaker. CONCLUSIONS: FDG-PET uptake in carotid plaques is correlated to gene expression of CD68 and other molecular markers of inflammation and vulnerability.

Reproducibility of (18)F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR.

OBJECTIVE: To investigate reproducibility of fluorine-18 fludeoxyglucose ((18)F-FDG) uptake on (18)F-FDG positron emission tomography (PET)/CT and (18)F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: 30 patients with HNSCC were included in this prospective study. The patients were scanned twice before radiotherapy treatment with both PET/CT and PET/MR. Patients were scanned on the same scanners, 3 days apart and according to the same protocol. Metabolic tumour activity was measured by the maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively), and total lesion glycolysis from the metabolic tumour volume defined from ≥50% SUVmax. Bland-Altman analysis with limits of agreement, coefficient of variation (CV) from the two modalities were performed in order to test the reproducibility. Furthermore, CVs from SUVmax and SUVpeak were compared. The area under the curve from cumulative SUV-volume histograms were measured and tested for reproducibility of the distribution of (18)F-FDG uptake. RESULTS: 24 patients had two pre-treatment PET/CT scans and 21 patients had two pre-treatment PET/MR scans available for further analyses. Mean difference for SUVmax, peak and mean was approximately 4% for PET/CT and 3% for PET/MR, with 95% limits of agreement less than ±20%. CV was small (5-7%) for both modalities. There was no significant difference in CVs between PET/CT and PET/MR (p = 0.31). SUVmax was not more reproducible than SUVpeak (p = 0.09). CONCLUSION: (18)F-FDG uptake in PET/CT and PET/MR is highly reproducible and we found no difference in reproducibility between PET/CT and PET/MR. ADVANCES IN KNOWLEDGE: This is the first report to test reproducibility of PET/CT and PET/MR.

Coregulation of glucose uptake and vascular endothelial growth factor (VEGF) in two small-cell lung cancer (SCLC) sublines in vivo and in vitro.

We examined the relationship between (18)F- labeled 2-fluro-2-deoxy-d-glucose (FDG) uptake, and expression of glucose transporters (GLUTs) in two human small-cell lung cancer (SCLC) lines CPH 54A and CPH 54B. Changes in the expression of GLUTs and vascular endothelial growth factor (VEGF) during 12-, 18-, and 24 hours of severe hypoxia in vivo (xenografts) and in vitro (cell cultures) were recorded for both tumor lines. The two SCLC lines are subpopulations of the same patient tumor. In spite of their common genomic origin they represent consistently different metabolic and microenvironmental phenotypes as well as treatment sensitivities. There were higher levels of Glut-1 protein in 54B and a correspondingly higher FDG uptake in this tumor line (P<.001). During hypoxia a significant upregulation of in VEGF mRNA, GLUT-1 mRNA, and Glut-1 and -3 protein occurred with a distinctly different time course in the two cell lines. A similar co-upregulation of GLUT and VEGF was seen in hypoxic tumors of both lines. There were no significant changes of HIF-1alpha mRNA during hypoxia in either of the cell lines. A more detailed understanding of such correlations between glucose metabolism, angiogenesis, and microenvironmental phenotype of tumors, by positron emission tomography (PET) and molecular techniques might further sophisticate our interpretation of glycolytic predominance in tumors as seen by 18FFDG PET.

Dynamic cholescintigraphy: induction and description of gallbladder emptying.

UNLABELLED: The main purposes of this study were to investigate the best parameter for describing gallbladder emptying and whether gallbladder bile emptying should be induced with a bolus injection or continuous infusion of cholecystokinin-octapeptide (CCK-8). METHODS: Gallbladder emptying was measured by dynamic cholescintigraphy. Twelve healthy subjects and six patients with gallstones were examined twice with CCK-8 infusion cholescintigraphy, 0.3 ng CCK-8 kg per min for 60 min under identical circumstances. Another six healthy subjects randomly received bolus injection (0.04 microgram/kg) and infusion of CCK-8 (0.3 ng/kg per min for 60 min), respectively, during cholescintigraphy on two separate occasions. The choice of bolus dose was based on recommendations from the CCK-8 manufacturer. The infusion dose was chosen to produce plasma CCK concentrations similar to postprandial plasma CCK levels. RESULTS: A parameter of gallbladder emptying, mean ejection fraction (EF), was defined as 100% minus the area under the time-activity curve normalized to 100% and divided by the time interval from maximum to minimum counts per minute. This parameter proved superior to the well known parameters, EFmax. and EF30, in regard to reproducibility in healthy subjects. The slope of the regression line for the mean EF was 0.998 and the intercept value approximately 0% (p = 0.0001). The mean coefficient of variation was 4%. Apart from a higher mean coefficient of variation, similar reproducibility results were seen in the six patients. The measurements of EF30 in healthy subjects scattered more widely around the mean compared to the mean EF and EFmax, which indicates poorer ability to separate normal from abnormal gallbladder emptying. Intravenous bolus injection of CCK-8 resulted in incomplete gallbladder emptying with a mean EF value of 16% (s.d. 9%; range 7%-32%) compared to 49% (s.d. 7%; range 37%-57%) following CCK-8 infusion (p = 0.004). Abdominal discomfort was observed in all subjects after administration of the bolus injection, whereas no complaints were reported during infusion. CONCLUSION: Mean EF is the best parameter for describing gallbladder emptying. Moreover, slow infusion of a physiological dose of CCK-8 is preferable to induce gallbladder emptying because it results in more complete emptying and has no side effects.

Esophageal scintigraphy: reproducibility and normal ranges.

Esophageal scintigraphy has been rather widely used, but much debated as a simple screening method of esophageal dysfunction. However, reports of normal ranges, age dependence and reproducibility are very limited. We studied 60 healthy subjects with a mean age of 43 yr (26, 19, 15 subjects aged 20-39, 40-59, and 60-79 yr) to establish normal ranges and variations of esophageal mean transit time and residual activity measured by a radionuclide method using [99mTc] pertechnetate labeled water. Mean transit time was calculated by Zierler's formula. The median values and 95% percentiles of single measurements of MTT and residual activity in the supine position were 6.1 (3.2-11.5) sec and 11.5 (3.0-50)%, respectively. The coefficients of variation (CV) were 20%-35% for mean transit time and 85%-120% for residual activity in the sitting and supine positions. When double measurements were used, the CVs were reduced to 10% for MTT and 40% for residual activity in the supine position. The values did not change with age except for a higher frequency of spikes in subjects over 40 yr. The study has demonstrated that mean transit time for radiolabeled water in the esophagus of healthy subjects, measured by double determinations, has rather low, age-independent, interobserver and intersubject variabilities. In contrast, measurements of residual activity shows unacceptably high variations.

Electrical admittance for filling of the heart during lower body negative pressure in humans.

To evaluate whether electrical admittance of intracellular water is applicable for monitoring filling of the heart, we determined the difference in intracellular water in the thorax (Thorax(ICW)), measured as the reciprocal value of the electrical impedance for the thorax at 1.5 and 100 kHz during lower body negative pressure (LBNP) in humans. Changes in Thorax(ICW) were compared with positron emission tomography-determined C(15)O-labeled erythrocytes over the heart. During -40 mmHg LBNP, the blood volume of the heart decreased by 21 +/- 3% as the erythrocyte volume was reduced by 20 +/- 2% and the plasma volume declined by 26 +/- 2% (P < 0.01; n = 8). Over the heart region, LBNP was also associated with a decrease in the technetium-labeled erythrocyte activity by 26 +/- 4% and, conversely, an increase over the lower leg by 92 +/- 5% (P < 0.01; n = 6). For 15 subjects, LBNP increased thoracic impedance by 3.3 +/- 0.3 Omega (1.5 kHz) and 3.0 +/- 0.4 Omega (100 kHz), whereas leg impedance decreased by 9.0 +/- 3.3 Omega (1.5 kHz) and 6.1 +/- 3 Omega (100 kHz; P < 0.01). Thorax(ICW) was reduced by 7.1 +/- 1.9 S. 10(-4) (P < 0.01) and intracellular water in the leg tended to increase (from 37.8 +/- 4.6 to 40.9 +/- 5.0 S. 10(-4); P = 0.08). The correlation between Thorax(ICW) and heart erythrocyte volume was 0.84 (P < 0.05). The results suggest that thoracic electrical admittance of intracellular water can be applied to evaluate changes in blood volume of the heart during LBNP in humans.

Cholescintigraphy in patients with acute cholecystitis before and after percutaneous gallbladder drainage.

OBJECTIVE: To investigate gallbladder function by use of cholescintigraphy in patients with acute cholecystitis before and after percutaneous gallbladder drainage. DESIGN: A cholescintigraphy was performed in 40 patients with acute cholecystitis before and after the performance of percutaneous gallbladder drainage. During the post-drainage cholescintigraphies, a cholecystokinin stimulation was performed to investigate gallbladder emptying in 12 selected patients. Gallbladder pressure and volume were measured before drainage in another group of 12 patients with acute cholecystitis. RESULTS: As expected, no gallbladder activity was observed in the cholescintigraphies before drainage, except in a patient with an occluding stone in the common bile duct. Cystic duct patency and gallbladder activity were seen in 80% of patients in cholescintigraphies performed after drainage but before any other treatment. Post-drainage cholescintigraphy revealed a mean gallbladder ejection fraction of 24%, which is significantly lower than the corresponding value in normal individuals and gallstone patients without cholecystitis (n = 12). Gallbladder pressure and volume were markedly increased compared with normal values. CONCLUSION: The relief of increased gallbladder pressure and volume appears to be important for the re-establishment of gallbladder function.

Quantitative hepatobiliary scintigraphy and endoscopic sphincter of Oddi manometry in patients with suspected sphincter of Oddi dysfunction: assessment of flow-pressure relationship in the biliary tract.

OBJECTIVE: In the present study, the diagnostic efficacy of quantitative hepatobiliary scintigraphy (QHBS) was compared with that of endoscopic sphincter of Oddi (SO) manometry (ESOM) in patients with a suspected SO dysfunction (SOD) of biliary type II or III. METHODS: Twenty cholecystectomized patients with SOD biliary types II and III were investigated by QHBS and by ESOM. Twenty asymptomatic cholecystectomized patients served as controls for scintigraphy. ESOM was performed by applying the station pull-through method. Then SO basal pressure and phasic contraction characteristics were determined. During QHBS, time-activity curves were generated, and the time-to-peak (Tmax), the half-time of excretion (T(1/2)), the duodenal appearance time (DAT) and the hilum-to-duodenum transit time (HDTT) were then calculated. At the 60th minute of QHBS, 5 ng/kg body weight/min caerulein was administered. RESULTS: In patients with SOD and elevated SO basal pressure (> 40 mmHg), QHBS parameters, such as Tmax and T(1/2) calculated from regions of interest over the hepatic hilum and common bile duct, HDTT and DAT proved to be significantly increased compared to controls: 28.7 +/- 4.3 versus 21.1 +/- 4.6 min, 39.7 +/- 15.4 versus 18.8 +/- 2.6 min, 9.0 +/- 3.6 versus 2.3 +/- 1.3 min and 27.1 +/- 4.9 versus 16.6 +/- 3.0 min, respectively. In contrast, in patients with SOD and normal SO basal pressure, QHBS parameters did not differ significantly from the controls. For the pooled data on the symptomatic patients with SOD, a statistically significant linear correlation was found between the SO basal pressure and the QHBS parameters. Although HDTT was the most sensitive scintigraphic parameter (89%), the combined sensitivity and specificity of Tmax and T(1/2) of the common bile duct reached 100%. No scintigraphic sign of a paradoxical response to cholecystokinin was detected. CONCLUSIONS: QHBS is a useful non-invasive diagnostic method for the selection of SOD patients with an elevated SO basal pressure. A significant correlation has been established between the trans-papillary bile flow measured by QHBS and the SO basal pressure determined by ESOM.

Oral cholecystography compared to cholescintigraphy for evaluation of cystic duct patency prior to ESWL treatment.

In a prospective, blinded study of 109 patients with cholecystolithiasis, oral cholecystography and 99Tcm-EHIDA cholescintigraphy were compared in terms of reliability for demonstrating cystic duct patency: one of the prerequisites for extracorporeal shock wave lithotripsy (ESWL) treatment of cholecystolithiasis. Patients with a positive result on one or both tests were regarded as having cystic duct patency. Patients with negative and uncertain result of both tests or one of each were regarded as having no cystic duct patency. Concordance between the two tests was obtained in 93 of 109 patients. The diagnostic reliability of cholescintigraphy and oral cholecystography were 95 and 86%, respectively (P < 0.05), suggesting a more precise determination of gallbladder filling with scintigraphy.

Positron emission tomography of incidentally detected small pulmonary nodules.

The aim of this study was to assess the value of fluorodeoxyglucose positron emission tomography (FDG PET) imaging of small pulmonary nodules incidentally detected by spiral computed tomography (CT) in a high-risk population. Ten patients (five females, five males, aged 54-72 years) were recruited from an ongoing 4-year placebo controlled intervention study of the effect of inhaled steroids in 300 smokers with moderate to severe chronic obstructive pulmonary disease. The participants received yearly CT scans of the chest. Patients with a negative chest radiograph at the time of inclusion, but with pulmonary nodules indeterminate for malignancy detected by conventional spiral CT on a subsequent scan, were referred for FDG PET. Histological diagnoses were sought for all nodules with FDG uptake or where CT showed that they had grown. Ten patients had pulmonary nodules indeterminate for malignancy (approx. 3.3% of the entire study population). The prevalence of malignancy in this group was 50%. The accuracy of PET was high, in spite of the fact that seven patients had nodules smaller than 15 mm and two patients had bronchoalveolar cell carcinoma. This small prospective study indicates that subsequent assessment with FDG PET of small pulmonary nodules incidentally detected by CT has the potential to minimize the numbers of invasive procedures performed in individuals with a benign pulmonary lesion. FDG PET also increases the possibility of an early diagnosis as compared to the strategy of watchful waiting.

Comparison of the dynamics of bile emptying by quantitative hepatobiliary scintigraphy before and after cholecystectomy in patients with uncomplicated gallstone disease.

PURPOSE: Quantitative hepatobiliary scintigraphy, a noninvasive method frequently used to diagnose several biliary tract disorders, shows abnormalities in bile secretion and outflow. It is well known that there are wide variations in the normal pattern of bile emptying, but the effect of cholecystectomy on the bile flow has not yet been investigated. The goal of the current study was to examine the dynamics and normal variations of bile flow by quantitative hepatobiliary scintigraphy before and after cholecystectomy in a group of patients with uncomplicated gallstone disease. METHODS: Twenty patients were evaluated before and after cholecystectomy through cholecystokinin octapeptide-augmented quantitative hepatobiliary scintigraphy, and quantitative parameters of bile emptying (Tmax: time to peak activity, T1/2: half-emptying time before and after cholecystokinin octapeptide and duodenum appearance time) were determined and then compared. RESULTS: Before operation, the bile outflow displayed wide variations, with a moderately delayed common bile duct emptying time in some patients. After cholecystectomy, the T1/2 of the common bile duct decreased significantly when compared with the preoperative status, with only minor patient-to-patient variation, indicating uniformly faster bile emptying (common bile duct T1/2 before and after operation: 30.5 +/- 14.8 and 18.8 +/- 2.6 min, respectively). Cholecystokinin octapeptide administration caused rapid bile outflow from the common bile duct, with a significant decrease in the T1/2 parameters before and after cholecystectomy. CONCLUSIONS: In patients with their gallbladders in situ, the bile emptying rate showed wide variations and may be moderately slow without distal common bile duct obstruction. After cholecystectomy, the rate of bile emptying accelerated and showed only minor variations, thereby increasing the sensitivity of quantitative hepatobiliary scintigraphy for showing partial biliary obstruction.

[Percutaneous cholecystectomy in acute cholecystitis]. / Perkutan kolecystostomi ved akut kolecystit.

Seventy-two patients with acute cholecystitis were treated with initial ultrasound-guided percutaneous transperitoneal cholecystostomy (PTCS). PTCS could be performed in all 72 patients almost without procedure related complications, and subsequent elective treatment could be done in all, except three patients where acute cholecystectomy was necessary because of accidental catheter dislocation. Seven patients died of their severe underlying illness without relationship to PTCS or cholecystitis. Eight patients with acalculous cholecystitis had no further treatment after removal of the drainage catheter. It is concluded that PTCS is a safe method for acute drainage in patients with acute cholecystitis.

[Uncomplicated gallstones: who should be operated on?]. / Ukomplicerede galdeblaeresten: Hvem skal opereres?

Gallstones are common and occur asymptomatically or symptomatically with or without complications. Treatment is only required for symptomatic gallstones and complications in gallstones. Laparoscopic cholecystectomy is the treatment of choice for symptomatic gallstones and is performed with an increasing frequency. One may fear, that the indications for cholecystectomy have changed, and surgery is now undertaken for a lesser degree of morbidity. Cholecystectomy does not increase life expectancy, and 20-30% of patients cholecystectomized for symptomatic gallstones complain of abdominal pain of unknown origin after the operation. New valid parameters in order to predict which patients will benefit from cholecystectomy are therefore necessary. Symptoms specific to gallstones are not precisely known, and greatest success in treatment seems to be related to the occurrence of severe, often steady pain, of hours' duration, often located in the epigastrium or upper right quadrant, with or without radiation and/or vomiting. Dyspepsia alone is not an indication for cholecystectomy. Psychological vulnerability may predict a poor outcome after cholecystectomy and should lead to reconsideration of the indication for surgery.

[Positron emission tomography. A new measurement method for imaging of regional and biochemical parameters]. / Positronemissionstomografi. En ny målemetode til billedmaessig fremstilling af regionale fysiologiske og biokemiske parametre.

Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon (11C), oxygen (15O), and nitrogen (13N) elements. With the tomographic principle of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment.

[Postoperative morbidity among alcohol abusers]. / Postoperativ morbiditet blandt alkoholmisbrugere.

Retrospective studies suggest increased postoperative morbidity among alcohol misusers. We have prospectively studied the risk associated with alcohol intake among patients undergoing surgery. We investigated 15 persons who required colorectal surgery and who were drinking at least five Danish drinks per day. These patients were matched for sex, nutrition, age, weight, cardio-pulmonary disease, diagnosis anesthesia, and surgery to 15 control persons who were consuming no more than two drinks daily. None of the patients showed signs of liver disease. The alcohol group developed more postoperative complications than controls (67 vs 20%, p < 0.05) and hospital stay was prolonged (20 vs 12 days, p < 0.05). Preoperatively, alcohol misusers had reduced left ventricular ejection fraction (54 vs 68%, p < 0.01). Delayed-type hypersensitivity responses were reduced in the alcohol group before (53 mm2 vs 78, p < 0.05) and after (18 mm2 vs 55, p < 0.01) surgery. Alcohol misusers had significantly longer bleeding times. Surgical stress responses, as assessed by changes in plasma cortisol and catecholamines, were higher among alcohol misusers (p < 0.05). Postoperative morbidity was increased in alcohol misusers without signs of liver damage. The mechanisms may include subclinical cardiac insufficiency, immunosuppression, and decreased haemostatic function. Preoperative alcohol consumption may be a more important risk factor for postoperative morbidity than previously thought.

[Extracorporeal shockwave crushing of gallstones. Preliminary report]. / Ekstrakorporal galdestensknusning. En praeliminaer rapport. Hvidovre Hospitals Galdestensgruppe.

Extracorporeal shock wave lithotripsy (ESWL) was used for treatment of symptomatic x-ray negative stones in 23 patients. The number of ESWL sessions per patient was 1.8 (range 1-4). In 18 patients (78%), adequate fragmentation was seen comparable to results obtained elsewhere. Oral bile acid therapy was used after ESWL in the 18 patients mentioned and the mean follow-up period was five months (range 3-8 months). Four patients had by now passed all stones while 12 patients still had remaining stone fragments and one patient a gallstone. After ESWL, one patient was and one patient a gallstone. After ESWL, one patient was referred for cholecystectomy at his own request. Of the remaining five patients, cholecystectomy was performed in two and was scheduled for in three. Complications after ESWL were seen in two patients who developed acute pancreatitis. Thus, our preliminary experience shows that ESWL resulted in fragmentation and passing of gallbladder stones, but not without complications. Like the gallstone groups in Lyon, Montreal and Munich we are convinced that ESWL should be performed in accordance with prospectively designed protocols in order to establish optimal planning of indications and strategies for future treatment.

[Continuing medical education via questionnaire studies. Three pilot projects for anesthesiology, cardiology and neurology]. / Efteruddannelse af laeger via spørgeskemaundersøgelser. Tre pilotprojekter inden for anaestesiologi, kardiologi og neurologi.

The Danish Medical Association and the scientific societies have initiated three studies to evaluate the use of questionnaires for continuous medical education. One study was a questionnaire in anaesthesiology with 30 questions with answers yes/no/no answer, which was sent to 600 specialists in anaesthesiology. One study was in cardiology with a multiple choice questionnaire, sent to 300 general practitioners and 75 specialists in internal medicine outside cardiology. One study concerned the educational value of State-of-the-Art articles about neurology in Ugeskrift for Laeger (Journal of the Danish Medical Association) sent to 500 doctors outside neurology. All questionnaires were sent anonymously, with one general reminder. For the anaesthesiology study 234 questionnaires were returned (40.5%). In the cardiology study 195 questionnaires were returned (52%). For the study on neurology 278 answered (56%). Only about half of the questionnaires were returned for the three studies, and a lot of effort and resources were put into the studies. An extension from these small pilot studies to a general systematic continuous methodology with updated questionnaires in the postgraduate medical education seems troublesome. An optional self-registration for medical education such as The Canadian "Mocomp concept" might be a more realistic suggestion.

Gastric potential difference measurements. The gastric mucosal integrity and function studied with a new method for measurement of the electric potential difference across the stomach wall.

PD--the electric potential difference across the gastric mucosa--is a variable used to describe the gastric mucosal integrity and function. A new, reliable, and easily applied method for gastric PD measurements corrected for the disturbing liquid junction potentials between gastric juice and the PD measuring probe is presented. PD is measured with the gastric lumen negative, and a numeric reduction in PD is used as an expression of an injured mucosal condition. A reduced gastric PD is found along with a reduced gastric mucosal blood flow after intravenous indomethacin in anesthetized dogs. Increasing the FFA/albumin ratios in mini-pigs causes vasoconstriction and PD reduction. Short hypoxia and selective gastric ischemia cause a reversible PD reduction and no morphologic changes in anesthetized dogs, but ischemia for 1 h causes more permanent changes in PD, pH, and morphology. This damage can be reduced by allopurinol pretreatment, possibly due to the inhibition of oxygen-derived free radical formation. Gastric PD and pH were measured in volunteers and duodenal ulcer patients during Stroop's color word conflict test, in which mental stress causes sympathetic activation. A PD reduction and a pH increase were found along with stress induction, thereby indicating an influence of mental stress on stomach mucosal function. It is concluded that gastric PD measurement may be useful in ulcer pathogenetic research, and a sufficient gastric mucosal blood flow is stressed as being important for the mucosal defense.