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Biomedical subjects

J J Gonvers

Publications and source records attributed to J J Gonvers.

At least 55 records · Page 3Linked to original sources
PubMed1997

Overuse of upper gastrointestinal endoscopy in a country with open-access endoscopy: a prospective study in primary care.

BACKGROUND: This prospective observational study was aimed at evaluating the appropriateness of use of upper gastrointestinal endoscopy (UGE) in primary care in a country with open access to and high availability of the procedure. METHODS: Outpatients were consecutively included in two clinical settings: Setting A (20 primary care physicians during 4 weeks) and B (university-based outpatient clinic during 3 weeks). In patients undergoing UGE, appropriateness of referral was judged by explicit Swiss criteria developed by the RAND/UCLA panel method. RESULTS: Patient visits (8135) were assessed. Six hundred eleven patients complained of upper gastrointestinal symptoms. Physicians decided to perform UGE in 63 of these patients. Twenty-five (40%) of the endoscopies were rated appropriate, 7 (11%) equivocal, and 31 (49%) inappropriate. Overuse of UGE occurred in 5.1% (setting A: 4.7%; setting B:6.5%; p = 0.39) of the patients who presented with upper gastrointestinal symptoms. The decision to perform UGE in previously untreated dyspeptic patients was the most common clinical situation resulting in overuse. CONCLUSIONS: Inappropriate use of UGE is high in Switzerland. However, to better reflect primary care decision making, overuse should be related not only to patients referred for a medical test, but also to the number of patients who complain of the symptoms that would be investigated by the procedure.

Adolescent↗
PubMed1997

Appropriateness of upper gastrointestinal endoscopy: comparison of American and Swiss criteria.

OBJECTIVE: Examine the reproducibility of the RAND method for developing criteria for the appropriateness of medical procedures. DESIGN: Comparison of two sets of explicit criteria for appropriateness of upper gastrointestinal (UGI) endoscopy, developed by separate expert panels from two countries. SETTING: United States, Switzerland. STUDY PARTICIPANTS: National experts from different medical specialties involved in the referral or application of UGI endoscopy. INTERVENTIONS: Each panel was presented with about 500 clinical scenarios (indications) that were rated on a nine-point scale as to the appropriateness of performing UGI endoscopy for a patient with that clinical presentation. MAIN OUTCOME MEASURES: (1) distribution of appropriateness ratings and intrapanel agreement categories between the two panels, (2) between-panel agreement of assigning appropriateness for comparable indications and, (3) percentage of indications with major between-panel differences. RESULTS: Ratings for 2/3 of indications could be compared. The Swiss panel showed higher intrapanel agreement (54.6% versus 46.2%, P = 0.002). Seventy-eight per cent of comparable indications were assigned to identical categories of appropriateness by both panels (kappa = 0.76, P < 0.001). For 93% of the 376 comparable indications, there were no major interpanel differences. CONCLUSION: Separate expert panels in different countries, using a standardized methodology, produce criteria for appropriateness of medical procedures that are similar. Given the resources being invested throughout the world in developing criteria and guidelines, international collaboration in seeking optimal use of limited health care resources should be intensified.

Endoscopy, Gastrointestinal↗
PubMed1997

Is carbohydrate-deficient transferrin a specific marker for alcohol abuse? A study in patients with chronic viral hepatitis.

Carbohydrate-deficient transferrin, a transferrin isoform, is hailed as a new marker of chronic alcohol abuse, but its specificity is, however, not unequivocally accepted. The aim of the present study was therefore to determine carbohydrate-deficient transferrin levels in patients with chronic hepatitis B and C with or without documented chronic alcohol intake. Carbohydrate-deficient transferrin was measured using a double-antibody radioimmunoassay (CDTect, Pharmacia) in serum samples from 66 patients (45 males and 21 females; mean age: 39 years) with chronic viral hepatitis B (n = 20) or C (n = 46). Diagnosis of the underlying liver disease was established by liver biopsy. Carbohydrate-deficient transferrin levels were raised in 15 patients [23%; hepatitis B (n = 2) and hepatitis C (n = 13)]. In patients with chronic hepatitis B, the carbohydrate-deficient transferrin level was raised in two abstainers. In the 46 patients with chronic hepatitis C, 10 (22%) patients with an alcohol consumption of < 60 g/day for the men and 30 g/day for the women had raised carbohydrate-deficient transferrin levels. The overall specificity of carbohydrate-deficient transferrin for chronic alcohol abuse was thus 78%, suggesting an association between elevated carbohydrate-deficient transferrin levels and the presence of chronic viral hepatitis. Carbohydrate-deficient transferrin levels were not correlated with the histological grading or staging of chronic hepatitis B and C, or with biological markers of hepatic synthesis and cellular damage. Thus, an increased carbohydrate-deficient transferrin level may occur in patients with chronic viral hepatitis in the absence of chronic alcohol abuse. This fact should be kept in mind by physicians when using this marker to detect alcohol abuse.

Adult↗
PubMed1996

Influence of orlistat on the regulation of gallbladder contraction in man: a randomized double-blind placebo-controlled crossover study.

Orlistat (tetrahydrolipstatin) is a potent inhibitor of gastric and pancreatic lipase activity causing a diminution of free fatty acids in the intestinal lumen. The release of cholecystokinin (CCK) critically depends on the presence of free fatty acids in the small intestine. Postprandial CCK release and gallbladder contraction might be decreased by orlistat, potentially resulting in an increased risk of gallstone formation. In this double-blind, placebo-controlled, six-way crossover study, six healthy volunteers ingested in a randomized order three isocaloric test meals (250 ml) of identical osmolality with either orlistat (200 mg) or placebo: (a) a pure-fat meal (25 g triglycerides), (b) a mixed meal containing fat (8 g; 29% of caloric content), protein (10 g; 17%), and dextrose (32 g; 54%), and (c) a fat-free meal containing albumin (25 g; 46%) and dextrose (32 g; 54%). Gallbladder volumes were determined by ultrasonography, and plasma CCK, pancreatic polypeptide and gastrin levels by RIA. Gall-bladder contraction (AUC, % x 90 min; difference of means +/- 95% CI) in subjects receiving orlistat or placebo did not significantly differ after intake of the pure-fat meal (443+/-1174), the mixed meal (313+/-1170), or the fat-free-meal (-760+/-1180). The release of CCK (AUC; pM x 90 min; difference of means +/- 95% CI) was not different between orlistat and placebo after ingestion of the pure-fat meal (-18+/-64), the mixed meal (-45+/-62), and the fat-free meal (27+/-63). Likewise, the release of pancreatic polypeptide and gastrin was similar after intake of the meals with either orlistat or placebo. A single dose of orlistat did not reduce gallbladder motility after ingestion of meals with differing fat contents. The safety of long-term treatment with orlistat with respect to gallstone formation remains to be determined.

Adult↗
PubMed1996

Fixed versus titrated interferon-alpha 2B in chronic hepatitis C. A randomized controlled multicenter trial. The Swiss Association for the Study of the Liver.

BACKGROUND/AIM: Interferon has become the mainstay of treatment of chronic hepatitis C; however, duration of treatment and dose remain unresolved questions. The present study aimed to compare standard dose interferon with a titrated dose regimen carried out for 1 year. METHODS: This was a randomized, controlled multicenter trial. Patients with chronic hepatitis C were randomly allocated to a control group (n = 30), to a fixed dose group (n = 31) where interferon-alpha 2b 3 MU thrice weekly was given for 1 year or a titrated group (n = 34) where interferon was titrated starting at 5 MU thrice weekly to the lowest dose keeping the patient in remission as assessed by a normal ALT value. Liver biopsies were obtained before and at the end of treatment; in addition, galactose elimination capacity was measured as a measure of cytosolic function. RESULTS: In the control, fixed and titrated groups a complete response was achieved in 2/29, 10/28 and 15/31, respectively (p < 0.001 in favor of treatment, p = n.s. for the two treatments). The corresponding figure for sustained response was 1/29, 5/28 and 6/ 31 (p = n.s). In the titrated group, a complete (sustained) response was achieved with 5 MU in 2 (2), with 4 MU in 1 (0), with 3 MU in 4 (0), with 2 MU in 3 (0) and with 1 MU in 5 (4). Liver biopsy score and galactose elimination capacity improved significantly in responders but not in treatment failures. CONCLUSIONS: Both fixed and titrated dosing of interferon given for 1 year induced virus clearance in only a minority of treated patients. However, in a small number of patients, a complete and sustained response can be achieved with low doses of interferon. Dose titration could be an interesting approach to decreasing the cost and side effects in the treatment of chronic hepatitis C.

Adult↗
PubMed1996

Appropriateness and diagnostic yield of upper gastrointestinal endoscopy in an open-access endoscopy unit.

BACKGROUND AND STUDY AIMS: This prospective study tested the appropriateness of referrals for upper gastrointestinal endoscopy in an open-access endoscopy unit, using the criteria of the American Society for Gastrointestinal Endoscopy. It also examined whether there was any relationship between appropriateness of use and the presence of significant lesions detected by endoscopy. METHODS: Four hundred fifty consecutive upper gastrointestinal endoscopies were studied prospectively. The referral indication was recorded by the endoscopist before the procedure was performed, and was compared with the current criteria of the American Society for Gastrointestinal Endoscopy and with endoscopic findings. RESULTS: The appropriateness of referral was assessed in 442 consecutive endoscopies. Of these, 252 (57%) were judged to be appropriate. In 168 (88%) of the 190 endoscopies rated as inappropriate, the reason was that the patient had not undergone empirical anti-ulcer therapy before endoscopy. The probability of finding a significant lesion did not differ between the endoscopies judged to be appropriate (50%) and those judged to be inappropriate (46%) CONCLUSIONS: Upper gastrointestinal endoscopy was frequently used for inappropriate indications. The main reason for inappropriate use was insufficient treatment, or no treatment, of dyspeptic symptoms prior to endoscopy. In this study, the criteria for appropriateness did not predict the probability of finding a significant endoscopic lesion.

Adult↗
PubMed1996

Bacterial overgrowth during treatment with omeprazole compared with cimetidine: a prospective randomised double blind study.

BACKGROUND: Gastric and duodenal bacterial overgrowth frequently occurs in conditions where diminished acid secretion is present. Omeprazole inhibits acid secretion more effectively than cimetidine and might therefore more frequently cause bacterial overgrowth. AIM: This controlled prospective study compared the incidence of gastric and duodenal bacterial overgrowth in patients treated with omeprazole or cimetidine. METHODS: 47 outpatients with peptic disease were randomly assigned to a four week treatment regimen with omeprazole 20 mg or cimetidine 800 mg daily. Gastric and duodenal juice were obtained during upper gastrointestinal endoscopy and plated for anaerobic and aerobic organisms. RESULTS: Bacterial overgrowth (> or = 10(5) cfu/ml) was present in 53% of the patients receiving omeprazole and in 17% receiving cimetidine (p < 0.05). The mean (SEM) number of gastric and duodenal bacterial counts was 6.0 (0.2) and 5.0 (0.2) respectively in the omeprazole group and 4.0 (0.2) and 4.0 (0.1) in the cimetidine group (p < 0.001 and < 0.01; respectively). Faecal type bacteria were found in 30% of the patients with bacterial overgrowth. Basal gastric pH was higher in patients treated with omeprazole compared with cimetidine (4.2 (0.5) versus 2.0 (0.2); p < 0.001) and in patients with bacterial overgrowth compared with those without bacterial overgrowth (5.1 (0.6) versus 2.0 (0.1); p < 0.0001). The nitrate, nitrite, and nitrosamine values in gastric juice did not increase after treatment with either cimetidine or omeprazole. Serum concentrations of vitamin B12, beta carotene, and albumin were similar before and after treatment with both drugs. CONCLUSIONS: These results show that the incidence of gastric and duodenal bacterial overgrowth is considerably higher in patients treated with omeprazole compared with cimetidine. This can be explained by more pronounced inhibition of gastric acid secretion. No patient developed signs of malabsorption or an increase of N-nitroso compounds. The clinical significance of these findings needs to be assessed in studies with long-term treatment with omeprazole, in particular in patients belonging to high risk groups such as HIV infected and intensive care units patients.

Adult↗
PubMed1995

Role of nutrient fat and cholecystokinin in regulation of gallbladder emptying in man.

Postprandial gallbladder contraction is mainly regulated by cholecystokinin (CCK), but little is known about the dose-response relationship between CCK release and gallbladder contraction, in particular after meals with differing fat content. Decreased postprandial gallbladder emptying has been suggested to play a major role in the development of gallstones in man, and dietary factors may therefore be important in the pathogenesis of gallbladder stasis. We studied, in a randomized order, the effect of three isocaloric meals (250 ml) with identical osmolality on CCK release and gallbladder contraction in six healthy volunteers: (1) a pure fat meal (25 g triglycerides); (2) a mixed meal containing fat (8 g, 29% of caloric content), protein (10 g, 17%), and dextrose (32 g, 54%); and (3) a fat-free meal containing albumin (25 g, 46%) and dextrose (32 g, 54%). Gallbladder volumes and antral cross-sectional areas were determined by ultrasonography and plasma CCK and PP levels by RIA. The pure fat meal caused the highest CCK release (187 +/- 27; mean +/- SEM) and maximal (> 85% of fasting volume) gallbladder contraction (3172 +/- 361; AUC) as compared to the other two meals (P < 0.05). The mixed and the fat-free meal caused similarly low (< 50% of fasting volume) gallbladder contraction (6052 +/- 342 and 6134 +/- 500, respectively), although they induced markedly different CCK levels (157 +/- 12 and 87 +/- 13, respectively; P < 0.05). Gastric emptying rates were similar for all meals (18,500 +/- 3300, 18,600 +/- 2700 and 19,800 +/- 3100, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Conscious sedation for gastroscopy: patient tolerance and cardiorespiratory parameters.

BACKGROUND/AIMS: Most patients receive conscious sedation for gastroscopy. However, the benefit of the most often used combination of low-dose intravenous midazolam and topical lidocaine on patient tolerance remains poorly defined and has not been shown to outweigh cardiorespiratory risks. To respond to these issues, a randomized, double-blind, placebo-controlled prospective study was performed. METHODS: Two hundred outpatients undergoing diagnostic gastroscopy were assigned to receive either (1) midazolam (35 micrograms/kg) and lidocaine spray (100 mg), (2) midazolam and placebo lidocaine, (3) placebo midazolam and lidocaine, or (4) placebo midazolam and placebo lidocaine. RESULTS: Tolerance (visual analogue scale, 0-100 points; 0, excellent; 100, unbearable) improved as compared with placebo midazolam and placebo lidocaine by 23 points (95% confidence interval, 15-32) in group 1, 15 points (95% confidence interval, 7-24) in group 2, and 10 points (95% confidence interval, 2-18) in group 3. Increasing age (P < 0.001), low anxiety (P < 0.001), and male sex (P < 0.03), but not amnesia, were associated with better patient tolerance. Oxygen desaturation (< 1 minute) occurred in 8.2% and was not more frequent after midazolam treatment. Hypotension was rare (2.1%), and no adverse outcome occurred. CONCLUSIONS: Both low-dose midazolam (35 micrograms/kg) and lidocaine spray have an additive beneficial effect on patients tolerance and rarely induce significant alterations in cardiorespiratory monitoring parameters, thus supporting the widespread use of conscious sedation.

Adult↗
PubMed1995

Effect of cisapride on gallbladder motility after extracorporeal shock-wave lithotripsy.

BACKGROUND/AIMS: Altered gallbladder motility is regarded as one of the important factors involved in the formation and recurrence of gallstones. Previous studies have suggested that cisapride increases postprandial gallbladder contraction and may therefore be theoretically useful in preventing stone recurrence. The aim of our study was therefore to investigate the effect of cisapride on gallbladder motility in stone-free patients after extracorporeal shock-wave lithotripsy, as compared to healthy volunteers pair-matched for age and sex. METHODS: Each subject received cisapride or placebo in a double-blind, cross-over, random order. Gallbladder volumes were measured by ultrasonography in the fasting state and after intake of a standard liquid meal. Plasma cholecystokinin levels were determined by radioimmunoassay. RESULTS: Fasting gallbladder volumes were smaller in patients as compared to volunteers (20.7 +/- 1.3 ml vs. 46.0 +/- 9.2 ml; p < 0.05) but were not modified by cisapride (21.1 +/- 1.7 ml vs. 58.6 +/- 11.3 ml). The maximal postprandial decrease in gallbladder volume was similar in patients and volunteers (64.5 +/- 12% vs. 62 +/- 10%; NS) and was not significantly altered by cisapride (59 +/- 9.4% vs. 54 +/- 9%; NS). In patients, cisapride increased integrated postprandial gallbladder volume by accelerating gallbladder refilling as compared to placebo by 37 +/- 15% (p < 0.05). Integrated cholecystokinin plasma levels were similar in patients and volunteers and were 13.4 +/- 4.7% higher after cisapride as compared to placebo (p < 0.05). CONCLUSIONS: The results of this study suggest that cisapride does not alter postprandial gallbladder contraction but accelerates gallbladder refilling in patients free from gallstones after extracorporeal shock-wave lithotripsy. This effect of cisapride is probably due to an acceleration of gastric emptying also causing a secondary enhanced cholecystokinin release.

Adult↗
PubMed1994

[Evaluation of deviating liver tests in ambulatory practice].

The finding of disturbed hepatic function, associated with an unclear clinical picture or during of a health checkup, is frequent. A physician's approach to a patient presenting disturbed hepatic function tests does not depend on well-defined algorithms but requires a sound knowledge of hepatic function tests and indicators of hepatobiliary disease. There are two major categories of hepatic function tests: non-specific tests which may indicate the existence of hepatic disease, and specific tests which permit assessment of the nature of hepatic damage. To facilitate the search for an etiology, it is helpful to classify hepatobiliary diseases according to the type of disturbance of hepatic function. One may speak of hepatocellular necrosis if elevation of the transaminases is the sole or predominant feature, and of cholestasis if the elevation solely or essentially involves the alkaline phosphatases and gamma-GT. Chronic hepatitis C, alcoholism and obesity frequently underline an isolated elevation of the transaminases.

Biliary Tract Diseases↗
PubMed1994

Association of Crohn's disease and Cogan's syndrome.

We describe the case of a young woman with Cogan's syndrome and associated Crohn's disease. Systemic disease was manifested by oligoarthritis and valvular involvement. Crohn's disease has previously been described in two cases of Cogan's syndrome. We suggest therefore that Crohn's disease is pathogenetically related to Cogan's syndrome. For both, systemic involvement is characteristic, and immune-mediated mechanisms and vasculitis are thought to play a major pathogenetic role. Furthermore, both respond to treatment with corticosteroids.

Adult↗
PubMed1994

Conscious sedation, clinically relevant complications and monitoring of endoscopy: results of a nationwide survey in Switzerland.

There is no conclusive evidence that electronic monitoring during gastrointestinal endoscopy reduces patient morbidity and mortality. The aim of this nationwide Swiss survey was to assess the impact of monitoring on the outcome for patients. We therefore evaluated the monitoring practice and the rate of sedation-related clinically relevant complications in a country with a low monitoring prevalence, and compared the results with those for a country in which monitoring is widely applied. A questionnaire pertaining to 1990 was mailed to all 173 Swiss gastroenterologists. The response rate was 71.1%. Data from 115,200 endoscopies performed by 123 gastroenterologists were analysed. Sixty percent of the procedures were performed under sedation. Patient's vital signs were rarely monitored clinically (< or = 25%). Electronic monitoring was virtually never performed: oximetry was used by 2.5% and an electrocardiogram by 0.8%. The overall sedation-related complication rate was 0.10%, and no deaths occurred. Thus, the morbidity and mortality related to conscious sedation in Switzerland is low, and not higher than it is in countries with a high monitoring level, such as the USA (0.06-0.54%). We conclude that clinically detectable and relevant complications attributable to conscious sedation are rare even when vital parameters are not monitored routinely. There is need for a prospective study to evaluate the effect of electronic monitoring on the complication rate for average-risk patients undergoing routine gastrointestinal endoscopy.

Colonoscopy↗
PubMed1994

Evaluation of third-generation assays for detection of anti-hepatitis C virus (HCV) antibodies and comparison with presence of HCV RNA in blood donors reactive to c100-3 antigen.

We tested serum samples from blood donors by using first-, second-, and third-generation enzyme immunoassays or recombinant immunoblot assays. Second- and third-generation assays gave comparable results. Circulating hepatitis C virus RNA was found in a high proportion of reactive samples. A lack of reactivity or low-level reactivity predicted the absence of hepatitis C virus RNA in 100% of the cases.

Antigens, Viral↗