Cure of Helicobacter pylori infection in patients with reflux oesophagitis treated with long term omeprazole reverses gastritis without exacerbation of reflux disease: results of a randomised controlled trial

BACKGROUND

Helicobacter pylori gastritis may progress to glandular atrophy and intestinal metaplasia, conditions that predispose to gastric cancer. Profound suppression of gastric acid is associated with increased severity of H pylori gastritis. This prospective randomised study aimed to investigate whether H pylori eradication can influence gastritis and its sequelae during long term omeprazole therapy for gastro-oesophageal reflux disease (GORD).

METHODS

A total of 231 H pylori positive GORD patients who had been treated for > or =12 months with omeprazole maintenance therapy (OM) were randomised to either continuation of OM (OM only; n = 120) or OM plus a one week course of omeprazole, amoxycillin, and clarithromycin (OM triple; n = 111). Endoscopy with standardised biopsy sampling as well as symptom evaluation were performed at baseline and after one and two years. Gastritis was assessed according to the Sydney classification system for activity, inflammation, atrophy, intestinal metaplasia, and H pylori density.

RESULTS

Corpus gastritis activity at entry was moderate or severe in 50% and 55% of the OM only and OM triple groups, respectively. In the OM triple group, H pylori was eradicated in 90 (88%) patients, and activity and inflammation decreased substantially in both the antrum and corpus (p<0.001, baseline v two years). Atrophic gastritis also improved in the corpus (p<0.001) but not in the antrum. In the 83 OM only patients with continuing infection, there was no change in antral and corpus gastritis activity or atrophy, but inflammation increased (p<0.01). H pylori eradication did not alter the dose of omeprazole required, or reflux symptoms.

CONCLUSIONS

Most H pylori positive GORD patients have a corpus predominant pangastritis during omeprazole maintenance therapy. Eradication of H pylori eliminates gastric mucosal inflammation and induces regression of corpus glandular atrophy. H pylori eradication did not worsen reflux disease or lead to a need for increased omeprazole maintenance dose. We therefore recommend eradication of H pylori in GORD patients receiving long term acid suppression.

[Calprotectin: a fecal marker for diagnosis and follow-up in patients with chronic inflammatory bowel disease]

Chronic inflammatory bowel disease (IBD) is characterised clinically by periods of well being interspersed by exacerbations of disease activity. Differentiation between IBD and less severe disorders such as irritable bowel syndrome requires invasive and expensive diagnostic procedures. Diagnostic differentiation between active disease, symptoms due to residual constriction of the fibrotic lumen and functional symptoms is a well-known problem. There are not yet any laboratory parameters with sufficient discrimination in terms of sensitivity and specificity. Colonoscopy and histopathological examination remain the gold standards: in Crohn's disease this may be complex due to the variable localisation of the inflammatory process. Abdominal scintigraphic procedures, although informative, are complex and expensive. The recent assessment of faecal calprotectin, a calcium- and zinc-binding anti-inflammatory protein found in neutrophilic granulocytes and monocytes, offers an attractive alternative as an index of intestinal inflammation. We measured this stable marker in random stool samples from 187 patients including healthy volunteers, patients with endoscopically classified active IBD or IBD in remission, and patients with other gastrointestinal disorders. Disease activity was monitored by clinical symptoms, blood tests and endoscopy. Our results confirm previous literature findings that faecal calprotectin is a promising and useful non-invasive tool in the screening of patients presenting with abdominal pain and diarrhoea. Moreover, calprotectin seems helpful in differentiating between active and non-active IBD and possibly also in the monitoring of disease activity.

Non-occlusive mesenteric ischaemia: a common disorder in gastroenterology and intensive care

Non-occlusive mesenteric ischaemia is characterized by gastrointestinal ischaemia with normal vessels. In gastroenterology it is recognized as rare disease occasionally causing acute bowel infarction or ischaemic colitis. From intensive care literature this disorder is recognized as an early phenomenon during circulatory stress. This early mucosal ischaemia then leads to increased permeability, bacterial translocation, and further mucosal hypoperfusion. The damage is produced mainly during reperfusion following ischaemia with fresh inflow of oxygen and outflow of waste products into the systemic circulation. The mechanisms underlying non-occlusive mesenteric ischaemia include macrovascular vasoconstriction, hypoperfusion of the tips of the villi and shunting. It is very common in critically ill and perioperative patients, but also occurs in pancreatitis, renal failure and sepsis. Treatment options include aggressive fluid resuscitation and careful choice of vasoactive drugs. Control of reperfusion damage and new endothelin-antagonists are potentially useful new treatment options.

Change in anatomic distribution and incidence of colorectal carcinoma over a period of 15 years: clinical considerations

PURPOSE

Colorectal cancer is the second most common cancer in the Netherlands. Its incidence rates are among the highest in Europe. In the past decades, a right-sided shift of the subsite location of colorectal cancer has been reported. These changes in anatomic distribution might have clinical implications for the use of diagnostic or screening tools for colorectal cancer. This study was designed to investigate the change in incidence and anatomic distribution of colorectal cancer in a population over a period of 15 years.

METHODS

The incidence of colorectal cancer in an eastern part of the Netherlands (700,000 inhabitants) was determined for two years, 1981 and 1996. From the regional laboratory of pathology, data including age, gender, subsite location, and Dukes classification were collected. The subsite location of colorectal cancer was divided into two groups: proximal and distal (the latter being within sigmoidoscopy reach).

RESULTS

No differences in age and gender distribution were found. In 1981, the diagnosis of colorectal cancer was made in 232 patients in this region, and in 1996, it was made in 410 patients. The population remained almost stable during this time. Therefore, the incidence rose from 33 to 55 per 100,000 inhabitants from 1981 to 1996, respectively. In 1981, 25 percent of the carcinomas were proximal (to the sigmoid colon); this increased to 37 percent in 1996 ( P< 0.05).

CONCLUSIONS

The incidence of colorectal cancer has almost doubled from 1981 to 1996 in this Dutch region. The proportion of proximal colorectal cancer has increased from 25 to 37 percent. These findings add to the notion that sigmoidoscopy is not the optimal diagnostic or screening tool for colorectal cancer.

[Gastrointestinal surgery and gastroenterology. XIV. Mesenteric abnormalities in generalised vascular disease]

Various forms of vasculitis may result in mesenteric ischaemia, ischaemic colitis or aneurysm formation in the aorta or intestinal blood vessels. Vasculitides may involve large- and/or medium-sized vessels, medium- and/or small-sized vessels, or small-sized vessels only. It is essential to differentiate between the different forms of vasculitis since diagnostic tests and therapies differ greatly. Gastrointestinal manifestations of vasculitis can generally be detected using angiography, digital subtraction angiography and/or magnetic resonance angiography (MRA). Various laboratory tests are helpful in establishing the diagnosis in patients in whom vasculitis is clinically suspected. In addition, the diagnosis should be confirmed using histology or angiography if possible. Treatment of vasculitis not caused by chronic infection consists of high dose corticosteroids and, in the case of polyarteritis nodosa or vasculitis associated with anti-neutrophil cytoplasmic antibodies (ANCA), cyclophosphamide.

Exercise induces gastric ischemia in healthy volunteers: a tonometry study

Heavy physical exercise may cause gastrointestinal signs and symptoms, and, although splanchnic blood flow may decrease through redistribution by more than 50%, it is unclear whether these signs and symptoms relate to gastrointestinal ischemia. In 10 healthy volunteers, we studied the effect of exercise on gastric mucosal perfusion adequacy using air tonometry. Two relatively short (10 min) exercise stages were conducted on a cycle ergometer, aiming for 80 and 100% of maximum heart rate, respectively. The intragastric-arterial PCO(2) gradient (Delta PCO(2)) was elevated by 1.1 +/- 1.0 kPa over baseline values (-0.1 +/- 0.3 kPa) only after maximal exercise (P < 0.001). Delta PCO(2) positively correlated with the arterial lactate level taken as an index of exercise intensity (Spearman's rank test: r = 0.76, P < 0.0001). By bilinear regression analysis, a lactate level of 12 mmol/l, above which a sharp rise in the Delta PCO(2) occurred, was calculated. We conclude that, in healthy volunteers with normal splanchnic vasculature, gastric ischemia may develop during maximal exercise as judged from intragastric PCO(2) tonometry.

[PCO2 tonometry of the stomach]

Gastrointestinal luminal tonometry is a minimally invasive technique for measuring gastrointestinal ischaemia. Mucosal ischaemia leads to excessive production of tissue CO2 and thus to an increase of luminal PCO2. For this measurement, a nasogastric catheter is introduced with at its end a balloon permeable for CO2, this balloon is filled with air or liquid. After CO2 has diffused from the tissue into the lumen of the balloon, the PCO2 in the liquid or air is determined. Due to uncertainties about physiological background, methodology and clinical usefulness tonometry is not yet widely applied. The recent introduction of automated airtonometry, replacing the laborious and error-prone manual saline technique, makes tonometry more reliable and easier applicable in the clinical situation. Reliable measurements require inhibition of gastric acid production and measurement in a fasting condition. The lumen-blood PCO2 gradient is the most reliable parameter of gastrointestinal mucosal ischaemia. In the past intraluminal pH--calculated from the intraluminal PCO2 measured by tonometry and the bicarbonate concentration in the blood--has been the parameter most often used. Tonometric parameters are reliable indicators of morbidity and mortality in critically ill patients. The effect of 'tonometry-guided' treatment on the morbidity and mortality is still a matter of debate. Other than using tonometry as a global ('hemodynamic') monitoring device, selective monitoring of the regional perfusion of the digestive tract--such as for diagnostic purpose in suspected chronic ischaemia due to splanchnic arterial disease--is a promising new application area.

Nonvariceal upper gastrointestinal bleeding: differences in outcome for patients admitted to internal medicine and gastroenterological services

OBJECTIVE

It has been suggested that admission to a gastroenterology service (GAS) is associated with a better prognosis and lower cost for treatment of gastrointestinal (GI) diseases, such as upper GI bleeding (UGB). However, a large potential bias by higher comorbidity on internal medicine services (MED) could not be excluded from these studies. We therefore compared patients with upper GI bleeding admitted to a gastroenterology or internal medicine department, with special emphasis on prognostic factors, such as comorbidity, and outcome.

METHODS

Between 1991 and 1995, 322 patients were admitted to our hospital for UGB. Forty-five patients had variceal and 277 patients had nonvariceal upper GI bleeding (NUGB). Of 232 patients with primary NUGB, 125 were admitted to GAS and 93 to MED. The charts of these patients were revised, comorbidity was carefully recorded, and the Rockall risk score was calculated. All deaths were individually classified as unavoidable, mostly due to severe underlying illness, or potentially avoidable.

RESULTS

No differences in delay for endoscopy or treatment were observed between GAS and MED. The rebleeding, surgery, and mortality rates in GAS and MED patients were 11.6% versus 11.5% (NS), 7.8% versus 7.3% (NS), and 2.4% versus 10.8% (p = 0.02), respectively. Rockall scores differed between GAS and MED patients (3.1 +/- 1.8 vs 3.7 +/- 1.7, p = 0.02). The mortality rate stratified by Rockall score was lower for the GAS patients. However, individual analysis revealed that only three of 13 deaths were potentially avoidable: two of 10 at the MED and one of three at the GAS.

CONCLUSION

The lower mortality among nonvariceal upper GI bleeding patients admitted to a gastroenterological service compared to an internal medicine service was mainly due to lesser comorbidity. This effect was not detected by stratification according to Rockall, but shown with analysis of individual patient charts only. The latter underscores the potential pitfalls when comparing outcome or cost of treatment between different medical services.

[Gastrointestinal surgery and gastroenterology. VIII. Gastroenterologic aspects of chronic gastrointestinal ischemia]

The main cause of chronic gastrointestinal ischaemia is atherosclerosis. Stenotic lesions of the mesenteric circulation are relatively common, but lead to chronic ischaemic complaints due to collateral circulation in probably only 2-3 per 100,000 inhabitants per year. The classical presentation (post-prandial abdominal pain, weight loss, upper abdominal souffle) is present in a minority of patients only. Symptoms also occur after exercise. Gastric ulcers and diarrhoea are less frequent. Although patients with 2 and 3 vessel involvement (coeliac artery, superior mesenteric artery and inferior mesenteric artery) usually experience the most severe ischemic complaints, patients with single vessel involvement can also develop symptoms. In the diagnosis of cases with abdominal complaints, factors that aggravate or reduce the complaints anamnestically are the guideline for supplementary diagnostics. The more frequent causes of the symptoms are to be excluded first. Doppler-ultrasonography of the mesenteric vessels can detect most stenotic lesions accurately. To establish the diagnosis visceral angiography is needed. A new method of examination is magnetic resonance angiography (MRA). Another new method is tonometry during exercise: a PCO2 value in the lumen that is higher than that in the blood indicates ischaemia. Non-invasive treatment of chronic gastrointestinal ischaemia is aimed at reduction of the gastrointestinal metabolic workload by smaller meals, at suppression of acid secretion, at inhibition of the secretion of gastric acid and on risk factors for atherosclerosis.

Effect of gastric feeding on intragastric P(CO2) tonometry in healthy volunteers

PURPOSE

The tonometric detection of a high intragastric regional P(CO2) (PrCO2) reflecting an elevated intramucosal P(CO2) can be helpful to diagnose mucosal ischemia, if acid secretion is suppressed to avoid intragastric CO2 production through buffering of acid by bicarbonate in the stomach. It is recommended to perform tonometry in the fasting state, but this may hamper feeding of the critically ill. On the other hand, postfeeding tonometry could serve as a diagnostic stress test because feeding increases mucosal blood flow demand, provided that the meal itself does not hamper diffusion of CO2 from mucosa to tonometer balloon and does not generate intragastric CO2, independently from intramucosal P(CO2). We therefore studied the effect of a standard meal on intragastric PrCO2 tonometry in healthy volunteers with suppression of meal-stimulated gastric acid secretion and, presumably, with an adequate mucosal blood flow reserve.

MATERIAL AND METHODS

The gastric juice pH and tonometric PrCO2 were measured in 14 human volunteers, after gastric acid secretion suppression by either ranitidine (100-mg bolus, followed by 25 mg/h i.v., n = 7) or by ranitidine plus pirenzepine (10-mg bolus, followed by 3 mg/h i.v., n=7) to suppress any residual meal-stimulated gastric acid secretion, before and at 30-minute intervals until 120 minutes after oral ingestion of a standard liquid test meal (Pulmocare [Abbott, the Netherlands]; 500 mL, 750 kcal, P(CO2) 5 mm Hg, pH 7.50).

RESULTS

The gastric juice pH, which was >4.0 in all individuals throughout the study, and the PrCO2 did not depend on the regimen for gastric acid secretion suppression, and therefore the data were pooled. The PrCO2 (median [range]) after feeding was 69% (56% to 170%) of baseline (42 [37-51] mm Hg) from 0 to 30 minutes (P < .001), 85% (72% to 167%) of baseline from 30 to 60 (P < .05), 97% (57% to 193%) from 60 to 90 minutes, and 112% (97% to 189%) of baseline from 90 to 120 minutes with a rise above baseline in 10 of 14 patients. In vitro, the liquid test meal generated CO2 after adding bicarbonate but not after hydrochloric acid.

CONCLUSION

We recommend intragastric tonometry to be performed in the fasting state and discourage tonometry after feeding as a stress test, because a single test meal changes tonometric PrCO2 in a time-dependent manner until 2 hours after gastric feeding of healthy volunteers. The fall in PrCO2 directly after feeding can be attributed to dilution, whereas a rise above baseline in some patients may have been caused, as supported by CO2 production after adding bicarbonate to the test meal in vitro, by CO2 production through buffering of meal-derived acid by gastric bicarbonate, in the absence of stimulated gastric acid secretion by feeding.

Increased gastric PCO2 during exercise is indicative of gastric ischaemia: a tonometric study

BACKGROUND

Diagnosis of gastric ischaemia is difficult and angiography is an invasive procedure. Angiographic findings may not correlate with clinical importance.

AIMS

To investigate whether tonometric measurement of intragastric PCO2 during exercise can be used to detect clinically important gastric ischaemia.

METHODS

Fourteen patients with unexplained abdominal pain or weight loss were studied. Splanchnic angiography served as the gold standard. Three patients were studied again after a revascularisation procedure. Gastric PCO2 was measured from a nasogastric tonometer, with 10 minute dwell times, and after acid suppression. Gastric and capillary PCO2 were measured before, during, and after submaximal exercise of 10 minutes duration.

RESULTS

Seven patients had normal angiograms; seven had more than 50% stenosis in the coeliac (n=7) or superior mesenteric artery (n=4). Normal subjects showed no changes in tonometry. In patients with stenoses, the median intragastric PCO2 (PiCO2) at rest was 5.2 kPa (range 4.8-11.2) and rose to 6.4 kPa (range 5.7-15.7) at peak exercise; the median intragastric blood PCO2 gradient increased from 0.0 kPa (range -0.8 to 5.9) to 1.7 kPa (range 0.9 to 10.3; p<0.01). Only two subjects had abnormal tonometry at rest; all had supernormal values at peak exercise. The PCO2 gradient correlated with clinical and gastroscopic severity; in patients reexamined after revascularisation (n=3), exercise tonometry returned to normal.

CONCLUSION

Gastric tonometry during exercise is a promising non-invasive tool for diagnosing and grading gastrointestinal ischaemia and evaluating the results of revascularisation surgery for symptomatic gastric ischaemia.

Reliable gastric tonometry after coronary artery surgery: need for acid secretion suppression despite transient failure of acid secretion

OBJECTIVE

To study the need for suppression of gastric acid secretion for reliable intragastric partial pressure of carbon dioxide (PCO2) tonometry by evaluating the effect of an oral dose of sodium bicarbonate before and after administration of the H2-blocker ranitidine to mimic CO2 generation following the buffering of acid by bicarbonate in patients after cardiac surgery.

DESIGN

Prospective, open, non-randomized clinical study.

SETTING

Cardiothoracic intensive care unit at a university hospital.

PATIENTS

10 patients after elective coronary artery bypass surgery.

INTERVENTIONS

An oral dose of 500 mg sodium bicarbonate before and after acid secretion suppression by 100 mg ranitidine as an intravenous bolus given at approximately 3 h after surgery (day 0) and on the first postoperative day (day 1).

MEASUREMENTS AND RESULTS

Intragastric PCO2 (iPCO2; tonometry), gastric juice pH (aspirate) and arterial blood gas values were measured. On day 0, the iPCO2 was 25 +/- 5 mmHg before and 31 +/- 5 mmHg after the bicarbonate dose, 29 +/- 5 mmHg after ranitidine infusion, and 31 +/- 5 mmHg after the bicarbonate dose following the ranitidine infusion (NS). On day 1, the basal iPCO2 was 32 +/- 4 mmHg and it increased to 56 +/- 25 mmHg following bicarbonate (p < 0.01). After ranitidine, the iPCO2 was 33 +/- 4 mmHg before and 40 +/- 14 mmHg after bicarbonate (NS). Basal gastric juice pH was > 4 in nine of ten patients on day 0 and > 4 in seven of ten patients on day 1.

CONCLUSIONS

Pharmacological suppression of gastric acid secretion is mandatory for reliable iPCO2 tonometry after cardiopulmonary bypass surgery, even when gastric acid secretion is transiently inhibited. In fact, gastric acid secretion was inhibited immediately after surgery, but returned on the first postoperative day in most patients, as judged from the bicarbonate back titration of gastric acid, even when gastric juice pH was relatively high.

Characteristics of time-dependent PCO2 tonometry in the normal human stomach

Factors that affect PCO2 measurement in balloon saline during gastrointestinal tonometry are unclear. They include carbon dioxide diffusion rate, correction factors for calculation of equilibrium PCO2 from measurements at saline dwell times that are shorter than needed for full equilibration, role of blood-gas analyser bias during ex vivo PCO2 measurements in saline, and normal values for intragastric PCO2 (PiCO2) and intramucosal pH (pHi) at equilibrium, and their differences from blood values. In a laboratory study, normal PCO2 changes in a saline-filled tonometer balloon placed in a saline bath at constant PCO2 were described by a non-linear model, with a half-time of mean 4.4 min and 95% equilibration at mean 83 min. In a study in 20 healthy volunteers, PiCO2 build up in a saline-filled tonometer balloon placed in the stomach, measured at dwell times of 10, 20, 30 and 60 min, was slightly (P < 0.05) slower than in vitro, with a half-time of mean 5.8 min and 95% equilibration at mean 110 min. Correction factors to derive equilibrium PiCO2 at short dwell times and independently from blood-gas analyser bias were calculated. The factors differed (P < 0.05) from those currently provided by the manufacturer. Normal threshold values (mean) were: equilibrium PiCO2 < or = 6.6 kPa, pHi > or = 7.33, PiCO2 to blood PCO2 difference < or = 1.1 kPa and pH difference > or = -0.06. PiCO2 did not differ from, and was directly related to, blood PCO2. These values provide a reference base for other studies and show that gastric mucosal PCO2 depends on alveolar ventilation if blood flow is adequate.

Occlusive and non-occlusive gastrointestinal ischaemia: a clinical review with special emphasis on the diagnostic value of tonometry

BACKGROUND

To review clinical features of the occlusive splanchnic ischaemia syndromes with special emphasis on the diagnostic value of tonometry.

METHODS

The English literature was reviewed with an emphasis on papers concerning anatomy and physiology of splanchnic perfusion, the clinical presentation and diagnostic procedures in occlusive splanchnic ischaemia syndromes.

RESULTS

Splanchnic ischaemia can result from hypovolaemic states, resulting in splanchnic vasoconstriction and ischaemia with normal splanchnic vessels (non-occlusive ischaemia) or from vascular stenoses (occlusive ischaemia). The former is frequently encountered in critically ill patients, whereas the latter is considered rare, despite a relatively high incidence of splanchnic atherosclerosis. The main problem hindering assessment of the incidence of symptomatic chronic splanchnic ischaemia is the lack of a diagnostic procedure separating symptom-free from symptomatic splanchnic atherosclerosis. Although angiography provides precise anatomical information, the correlation with symptoms is poor. From various studies it emerges that tonometry of luminal PCO2 enables assessment of ischaemia.

CONCLUSIONS

Splanchnic ischaemia may be more common than currently assumed, but a gold standard diagnostic tool is lacking. Tonometry of the gastric PCO2 may be the most promising technique for detecting and grading splanchnic ischaemia.

Occlusive and non-occlusive gastrointestinal ischaemia: a clinical review with special emphasis on the diagnostic value of tonometry

BACKGROUND

To review clinical features of the occlusive splanchnic ischaemia syndromes with special emphasis on the diagnostic value of tonometry.

METHODS

The English literature was reviewed with an emphasis on papers concerning anatomy and physiology of splanchnic perfusion, the clinical presentation and diagnostic procedures in occlusive splanchnic ischaemia syndromes.

RESULTS

Splanchnic ischaemia can result from hypovolaemic states, resulting in splanchnic vasoconstriction and ischaemia with normal splanchnic vessels (non-occlusive ischaemia) or from vascular stenoses (occlusive ischaemia). The former is frequently encountered in critically ill patients, whereas the latter is considered rare, despite a relatively high incidence of splanchnic atherosclerosis. The main problem hindering assessment of the incidence of symptomatic chronic splanchnic ischaemia is the lack of a diagnostic procedure separating symptom-free from symptomatic splanchnic atherosclerosis. Although angiography provides precise anatomical information, the correlation with symptoms is poor. From various studies it emerges that tonometry of luminal PCO2 enables assessment of ischaemia.

CONCLUSIONS

Splanchnic ischaemia may be more common than currently assumed, but a gold standard diagnostic tool is lacking. Tonometry of the gastric PCO2 may be the most promising technique for detecting and grading splanchnic ischaemia.

Catheter deadspace: a source of error during tonometry

Tonometry of PCO2 is a promising method for assessing the oxygen supply to demand ratio of the gastrointestinal mucosa in critically ill patients. A balloon-tipped tonometer is introduced into the stomach or sigmoid colon, and saline is instilled into the balloon. After a time to allow partial equilibration with intraluminal PCO2, saline is aspirated and PCO2 is measured. Intermittent instillation and aspiration of saline allows serial PCO2 measurements, provided correction factors are used to calculate the PCO2 value expected at full equilibration from the PCO2 values measured after short dwell times. The technique is not yet widely applied, partly because of methodological controversies. We evaluated the role of the catheter deadspace as a source of error during PCO2 tonometry. The increase in PCO2 in sigmoid-type tonometers with a normal length (normal tonometer (NT)) and in those with a 50% increase in length and thus deadspace (extended tonometer (ET)), in a saline bath at a PCO2 of 4.8 kPa was assessed. Saline dwell times were 10, 20, 30, 45, 60 and 90 min and the time-dependent PCO2 increase was determined at deadspace PCO2 values of approximately 4.0 and 8.0 kPa following contamination of the catheter deadspace after immersion in saline baths at PCO2 values of 4.8 and 9.6 kPa, respectively, before each measurement cycle. In another experiment, the tonometer was rinsed between measurement cycles to remove deadspace saline containing carbon dioxide and to obviate contamination of instilled saline. PCO2 was measured in a blood-gas analyser, taking into account measurement bias in saline. Failure to remove deadspace saline between measurement cycles resulted in an overestimation of 10% and 6% for the NT and 16% and 10% for the ET, at saline dwell times of 10 and 20 min, respectively, at a deadspace PCO2 of approximately 4.0 kPa. At a deadspace PCO2 of approximately 8.0 kPa, PCO2 was overestimated by 17%, 11% and 5% for the NT and 31%, 20% and 11% for the ET, at dwell times of 10, 20 and 30 min, respectively. Rinsing the NT/ET resulted in accurate assessment of PCO2 at all dwell times, but the dwell time-dependent increase in PCO2 was slightly slower in the ET, particularly at 10 min, after a sink effect of the increased deadspace. Hence, a previously unrecognized deadspace effect caused error during PCO2 tonometry, particularly with short dwell times. This potentially large error can be avoided by rinsing the tonometer before each measurement cycle, allowing accurate PCO2 tonometry even at 10-min saline dwell times, provided that correction factors are used that are specific for catheter size. These findings may help to widen the clinical applicability of tonometry.

Ranitidine bismuth citrate with clarithromycin versus omeprazole with amoxycillin in the cure of Helicobacter pylori infection

AIM

To compare the efficacy of ranitidine bismuth citrate plus clarithromycin (RBC-C) vs. omeprazole plus amoxycillin (OME-AMO) in the cure of Helicobacter pylori infection.

METHODS

In this double-blind, multicentre, parallel-group study 122 H. pylori-positive patients with active duodenal ulcer or gastritis, with confirmed history of duodenal ulcer, were randomized to treatment with ranitidine bismuth citrate 400 mg b.d. plus clarithromycin 500 mg b.d. or omeprazole 20 mg b.d. plus amoxycillin 1000 mg b.d. for 14 days, followed by 14 days of ranitidine bismuth citrate 400 mg b.d. or omeprazole 20 mg once daily, respectively, to facilitate ulcer healing. Endoscopy was carried out at the start of the study and 28 days after the end of treatment. At each endoscopy four biopsies were obtained from the antrum and four biopsies from the corpus, for rapid urease test, histology and culture. H. pylori infection was defined as a positive urease test, confirmed by histology or culture. Cure of H. pylori infection was defined as negative urease test, histology or culture from both sites.

RESULTS

Per-protocol, all-patients-treated and intention-to-treat cure rates (95% confidence interval) were, respectively, 90% (81-89%), 90% (82-89%) and 84% (74-93%) for ranitidine bismuth citrate plus clarithromycin, and 39% (27-54%), 44% (31-57%) and 41% (29-53%) for omeprazole plus amoxycillin, P < 0.00001. Both regimens were well tolerated. Eight patients were lost to follow-up, for lack of efficacy (one patient), adverse events (three patients) or refusal of second endoscopy (four patients).

CONCLUSION

Ranitidine bismuth citrate 400 mg b.d. with clarithromycin 500 mg b.d. is superior to omeprazole 20 mg b.d. with amoxycillin 1000 mg b.d. Ranitidine bismuth citrate with clarithromycin is the first dual therapy with high cure rates and good tolerance, and is easy to take. It may therefore prove a suitable first-line treatment in H. pylori infection.

Type of solution and PCO2 measurement errors during tonometry

OBJECTIVE

The choice of solution for gastrointestinal tonometry influences the PCO2 measurement bias, precision and the time required for equilibration. We compared saline with buffered solutions during in vitro tonometry, with respect to systematic and accidental measurement errors and equilibration time.

DESIGN

A prospective laboratory study.

MEASUREMENTS

Saline, phosphate, phosphate bicarbonate and succinylated gelatin solutions were equilibrated in a specialized blood gas tonometer at PCO2s of 2.7, 3.6, 4.5, 6.2 and 9.0 kPa, using calibration gases. Accidental errors were determined: the within-syringe decline of PCO2 and the effects of handling errors (five up and down movements of the plunger). The PCO2 build up in gastrointestinal tonometers was determined in 5000 ml saline baths with fixed PCO2 levels of 2.7 and 9.0 kPa.

RESULTS

The build up of PCO2 in phosphate bicarbonate and gelatin was about 4 and 2 times slower than in saline and phosphate, respectively, both for gas and gastrointestinal tonometers. The bias of the measured PCO2 at equilibrium was -15% for saline, and between -1 and 3% for phosphate, phosphate bicarbonate and gelatin. The precision was comparable among the solutions: 2 +/- 1% for saline, 2 +/- 1% for phosphate, 1 +/- 0% for phosphate bicarbonate and 1 +/- 1% for gelatin. The accidental errors were virtually absent with phosphate bicarbonate, intermediate with gelatin and largest with saline and phosphate.

CONCLUSION

Phosphate bicarbonate buffer and succinylated gelatin allow accurate PCO2 measurements, but their equilibration is too slow for clinical application. The advantage of phosphate over saline solution is a smaller bias only. Thus, both saline and phosphate are currently the tonometer solutions of choice, provided that strictly anaerobic conditions are applied and the bias by the blood gas analyzer is known.

In vitro evaluation of intragastric PCO2 measurement by air tonometry

OBJECTIVE

To assess the in vitro performance of a new device, the Tonocap, for semi-continuous air tonometry of regional PCO2 in the gastrointestinal tract.

METHODS

The tonometer consists of an air filled balloon-tipped catheter, connected to a prototype Tonocap system. The tonometer was placed in saline baths at steady-state PCO2's ranging from 0 to 105 torr, to evaluate bias, precision and reproducibility to PCO2 measurements. The response time was defined as the time needed to detect 95% of an instantaneous change in bath PCO2.

RESULTS

The bias of the PCO2 measurement (mean +/- SD) was -2 +/- 2% and reproducibility (coefficient of variation) was 2 +/- 1%. The response time was 19 +/- 2 min.

CONCLUSIONS

Tonocap air tonometry is simple and eliminates most sources of error associated with conventional saline tonometry. The bias, precision, reproducibility and response time in vitro are consistent with a clinically reliable device.

Gastric PCO2 tonometry is independent of carbonic anhydrase inhibition

Tonometric measurement of an elevated intragastric Pco2 and a decreased calculated gastric intramucosal pH can be used to detect gastric mucosal ischemia, provided that intraluminal production of CO2 through acid buffering by bicarbonate is avoided by adequate acid secretion suppression. If the diffusion rate is known, steady state Pco2 can be calculated when measurement intervals are used that are shorter than needed for complete equilibration. The CO2 diffusion might be influenced by the choice of acid-suppressive drugs, since some of them inhibit gastric carbonic anhydrase (CA) and CA facilitates diffusion of CO2/bicarbonate over the gastrointestinal mucosa. We therefore performed gastric Pco2 tonometry, using acid-suppressive regimens with and without CA inhibition. The diffusion rate of CO2 in a gastric tonometer was studied in healthy volunteers, following intravenously administered ranitidine (group I, N = 8) or ranitidine plus pirenzepine (group II, N = 12), a muscarinic antagonist with CA inhibiting capacities. Measurement intervals were 10, 20, 30 and 60 min. Neither the diffusion rate of CO2 (k = 0.13 +/- 0.02/min in group I and 0.11 +/- 0.02/min in group II), nor the steady-state Pco2 (38 +/- 3 mm Hg in group I and 40 +/- 4 mm Hg in group II), nor the gastric-blood differences in Pco2 and pH differed between groups. These results indicate that diffusion of CO2 into the tonometer balloon is independent of CA and thus of the type of gastric acid secretion inhibition.

Mechanism of clarithromycin resistance in clinical isolates of Helicobacter pylori

Seventy-three Helicobacter pylori-positive patients were treated with a combination of clarithromycin and ranitidine in order to eradicate the bacterium. Eradication was successful in 79.5%. In 15 patients eradication failed, and in 11 cases this was due to clarithromycin resistance. In one patient the infecting strain was resistant at the onset of treatment, while in the remaining 10 patients resistance developed during therapy. These isolates had also become resistant to various other antibiotics. Random amplified polymorphic DNA and restriction fragment end-labeling analysis of the isolates showed close genetic relatedness between pre- and post-treatment isolates, indicating that resistance was the result of selection of variants of the infecting strain rather then infection with an exogenous resistant strain. Nucleotide sequence comparisons revealed that all resistant isolates had a single base pair mutation in the 23S rRNA. Since this single point mutation results in co-resistance to various antibiotics at high frequencies, caution should be taken when using clarithromycin as a single antibiotic.

Computed tomography and granulocyte scintigraphy in active inflammatory bowel disease. Comparison with endoscopy and operative findings

The accuracy of computed tomography (CT) and [99mTc]HMPAO granulocyte scintigraphy (GS) for detection of bowel localization, inflammatory activity, and complications in acute inflammatory bowel disease (IBD) was prospectively studied in 32 patients. Of each bowel segment, findings on CT and GS were scored by one blinded observer. Findings on operation or endoscopy served as the gold standard. In Crohn's disease (CD, 17 patients), CT detected bowel pathology (sensitivity 71%, specificity 98%), abscesses (sensitivity and specificity 100%), and fistulas (sensitivity 80%, specificity 100%). In CD, GS had a sensitive of 79% and a specificity of 98% for detection of inflammatory activity. The detection of complications with GS was poor. Segmental inflammatory activity correlated with endoscopy-operative findings for CT (r = 0/86, P < 0.0001) and GS (r = 0.86, P < 0.0001). In ulcerative colitis (UC, 15 patients), GS predicted proximal extension of bowel involvement better than CT. In CD, CT is Superior to GS for localization of both active and fibrostenotic bowel disease, and in detection of the abscesses and fistulas. In UC, GS showed proximal extension more accurately than CT.

Secretion of tumour necrosis factor alpha and lymphotoxin alpha in relation to polymorphisms in the TNF genes and HLA-DR alleles. Relevance for inflammatory bowel disease

The genes for tumour necrosis factor alpha (TNF alpha) and lymphotoxin alpha (LT alpha; TNF beta) are tandemly arranged in the central region of the MHC. They may, therefore, be of importance for the aetiology of MHC-associated diseases. The authors have prospectively studied the secretion of TNF alpha and LT alpha in relation to polymorphisms at positions -308 and -238 in the TNF alpha gene (TNFA), and two polymorphisms in the first intron of the LT alpha gene (LTA), as well as HLA-DR in 30 patients with chronic inflammatory bowel diseases (IBD) and 12 healthy controls. In the Dutch population, the alleles of these four polymorphisms are present in only five combinations, called TNF-haplotypes: TNF-C, -E, -H, -I, and -P. Significant associations between TNF haplotypes and TNF alpha and LT alpha secretion were found when PBMC were cultured with T-cell activators, irrespective of disease. Mean TNF alpha secretion of individuals carrying the HLA-DR3 associated TNF-E haplotype was significantly higher, as compared to individuals without this haplotype (26 441 pg/ml versus 19 629 pg/ml; P = 0.014). Individuals carrying the TNF-C haplotype produced the lowest amount of TNF alpha (17 408 pg/ml; P=0.022). The TNF-C and TNF-E haplotypes differ only at position -308 in the promoter of TNFA. Individuals carrying the HLA-DR1 associated TNF-I haplotype produced significantly less LT alpha when compared to those who lack this haplotype (1979 pg/ml versus 3462 pg/ml; P = 0.006). As the TNF-I haplotype is also associated with low TNF alpha secretion, this haplotype thus defines a 'low secretor phenotype'. In conclusion, this is the first study to show associations between TNF haplotypes and TNF alpha and LT alpha secretion when T-cell stimulators are used. These findings will contribute to define disease heterogeneity in IBD and may be of relevance for understanding the pathogenesis of autoimmune diseases.

A review on treatment of bleeding peptic ulcer: a collaborative task of gastroenterologist and surgeon

The majority of patients presenting with acute upper gastrointestinal haemorrhage bleed from peptic diseases erosive gastritis and duodenal or gastric ulcers. Early gastroscopy is essential in order to reach a diagnosis, assess the prognosis, and institute appropriate therapy. In a meta-analysis it was shown that H2-antagonists significantly reduced mortality. However, two large, prospective and placebo-controlled studies with famotidine and omeprazole failed to show reduction of rebleeding or death. The value of endoscopic haemostatic therapy in patients with high-risk peptic ulcers (active bleeding and non-bleeding visible vessel) has been firmly established with 75% decrease in rebleeding and operation rate, and a 40% reduction in mortality. Risk factors for an adverse outcome are: elderly patients, concomitant diseases and large ulcers in the posterior duodenal bulb or on the lesser curvature. The mortality for emergency surgery in upper GI bleeding is still 10-50%. The mortality of elective operations is less than 2%. Some studies have reduced mortality by avoiding emergency surgery through early elective surgery in high-risk patients.

Differences in the intrinsic capacity of peripheral blood mononuclear cells to produce tumor necrosis factor alpha and beta in patients with inflammatory bowel disease and healthy controls

BACKGROUND

Tumor necrosis factor alpha (TNF alpha) and beta (TNF beta) appear to play an important role in the regulation of the inflammatory response. The aim of the present study was to investigate the intrinsic capacity of peripheral blood mononuclear cells (PBMC) to produce these cytokines.

METHODS

PBMC from 41 patients with Crohn's disease (CD), with ulcerative colitis (UC), and 23 healthy controls (HC) were cultured for 48 h in the presence of the T-cell activators anti-CD3 and anti-CD28. Biologically active total TNF (TNF alpha and beta), TNF alpha, and TNF beta production were measured using a bioassay for biologically active TNF and specific TNF alpha and TNF beta enzyme-linked immunosorbent assays.

RESULTS

Large interindividual differences in TNF production were observed. Production of biologically active TNF after T-cell stimulation was significantly decreased in UC patients as compared with HC and CD patients (median, 337 U/ml, 800 U/ml, and 1050 U/ml, respectively). Stimulated TNF alpha production in UC patients (median, 432 U/ml) and in CD patients (median, 537 U/ml) did not differ statistically significantly from HC (median, 730 U/ml) as compared with HC and UC patients(median, 800 U/ml and 837 U/ml, respectively).

CONCLUSIONS

These findings support the concept that UC and CD are homogeneous, clearly distinguishable disease entities but rather a heterogeneous group of diseases. Studies directed to assess the immunogenetic background of these different disease manifestations in IBD are underway.

Serum nitrate levels in ulcerative colitis and Crohn's disease

BACKGROUND

Nitric oxide is an important mediator in inflammatory and autoimmune-mediated tissue destruction and may be of pathophysiologic importance in inflammatory bowel disease. We studied whether serum levels of nitrate, the stable end-product of nitric oxide, are increased in active Crohn's disease or ulcerative colitis, in comparison with quiescent disease and healthy controls. The setting was the gastroenterology unit of the Free University Hospital, Amsterdam.

METHODS

In 146 patients--75 with ulcerative colitis and 71 with Crohn's disease--and 33 controls serum nitrate was measured by the Griess reaction after enzymatic conversion of nitrate to nitrite with nitrate reductase.

RESULTS

Median serum nitrate concentrations did not differ statistically significantly between ulcerative colitis (median, 34.2 mumol/l; range, 15.6-229.4 mumol/l), Crohn's disease (median 32.3 mumol; range 13.2-143.2 mumol/l), and healthy controls (median, 28.7 mumol/l; range, 13.0-108.4 mumol/l). However, when active ulcerative colitis patients (median, 44 mumol/l; range, 29.1-229.4 mumol/l were compared with inactive ulcerative colitis patients (median, 31.2 mumol/l; range, 15.6-59.7 mumol/l), a significant difference in nitrate concentration was found (p < 0.0001). A significant positive correlation was found between serum nitrate levels in ulcerative colitis and erythrocyte sedimentation rate (ESR) (r = 0.30, p - 0.01), leucocyte count (r = 0.27, p = 0.02), and thrombocyte count (r = 0.24, p = 0.04). Comparing active Crohn's disease patients (median, 37.5 mumol/l; range, 13.2-143.2 mumol/l) with inactive Crohn's disease patients (median, 31.3 mumol/l; range, 14.5-92.3 mumol/l) also showed a significant difference in serum nitrate concentration (p < 0.009). Serum nitrate levels correlated with the ESR (r = 0.26, p = 0.028) and serum albumin (r = 0.38, p = 0.004) as well.

CONCLUSION

Nitric oxide production is increased in both active ulcerative colitis and Crohn's disease and may be implicated in the pathogenesis of inflammatory bowel disease.

Splanchnic tonometry: a review of physiology, methodology, and clinical applications

The objective of this article is to review splanchnic tonometry. The English literature, involving both animal and human studies, was used for review, with emphasis on papers on physiological and methodological principles and clinical applications. Tonometry involves the measurement of intraluminal PCO2 as a measure of mucosal PCO2 in the gastrointestinal tract via a catheter in, for instance, stomach or sigmoid colon, and the calculation, with help of the blood bicarbonate content and the Henderson-Hasselbalch equation, of the mucosal pH (pHi). The latter is considered as a relatively simple index of the adequacy of mucosal blood flow. Concerning methodology, it is still unclear whether acid secretion should be inhibited for proper assessment of PCO2 in the stomach. Buffering of bicarbonate by gastric acid may elevate the intraluminal PCO2 independently from mucosal PCO2, thereby confounding pHi as a measure of perfusion adequacy. This can be prevented by inhibition of acid secretion. Authors have raised doubts whether the composite variable pHi is of additive value to the acid-base status of arterial blood, so that it is unclear whether a subnormal pHi is a specific and sensitive indicator of mucosal ischemia, as suggested by others on the basis of a decline in the pHi along the gastrointestinal tract in animals subjected to vascular occlusion or circulatory shock. Moreover, tissue PCO2 depends on the PCO2 of supplying blood. Conversely, the bicarbonate concentration in ischemic mucosa may not equal that in arterial blood. Taken together, an elevated tonometer fluid arterial blood PCO2-gradient might be a more sensitive and specific indicator of mucosal ischemia than a decrease in the pHi, analogous to an increase in tissue PCO2 and widening of the venoarterial PCO2 gradient during various types of hypoperfusion, in animals and humans. Although splanchnic ischemia is an early event in shock, the sensitivity and specificity of this index for mucosal ischemia and its clinical value, relative to that of the pHi, have not been formally evaluated yet. Nevertheless, the pHi has been suggested to be of predictive value for gastrointestinal complications, multiple organ failure, success or failure of weaning from mechanical ventilation, and outcome in critically ill patients. Tonometry may be a useful monitoring technique to guide treatment and to improve survival. Splanchnic tonometry is a relatively simple, noninvasive, and thereby promising technique to monitor the critically ill. However, some aspects need further evaluation before the technique can be advocated for routine use.

Effect of ranitidine on basal and bicarbonate enhanced intragastric PCO2: a tonometric study

A high intragastric PCO2 (iPCO2), determined tonometrically, is the main factor participating in a low gastric intramucosal pH (pHi) and may point to gastric mucosal ischaemia. iPCO2 might also increase, however, after buffering of gastric acid by bicarbonate; the magnitude of this effect and the efficacy of H2 blockers to prevent it are unclear. Ten healthy volunteers (20-24 years) were studied at baseline and after oral ingestion of 500 mg sodium bicarbonate. The same test was carried out one hour after intravenous injection of 100 mg ranitidine. A glass pH electrode for continuous gastric juice pH measurements and a Tonomitor catheter were placed 10 cm distally from the gastro-oesophageal junction. iPCO2 was measured in saline boluses, infused at 30 minute intervals in the balloon at the tip of the Tonomitor. Before ranitidine was given, basal iPCO2 (mean (SD)) was 8.40 (2.53) kPa, and increased to 19.20 (5.87) kPa after sodium bicarbonate (p < 0.001). After ranitidine, the gastric juice pH increased from 1.8 (0.9) to 5.6 (1.3) (p < 0.05), while basal iPCO2 was 5.60 (0.67) kPa (p < 0.01) and did not change after sodium bicarbonate (6.27 (2.67) kPa)). iPCO2 values after acid secretion suppression were similar to those in capillary blood (5.60 (0.40 kPa)). The difference between intragastric and blood PCO2 during normal acid secretion probably results from buffering of gastric acid by gastric bicarbonate, rather than by duodenogastric reflux or saliva entering the stomach. During acid secretion suppression, intragastric equals blood PCO2, even after oral ingestion of sodium bicarbonate. Hence, acid secretion inhibition is mandatory for proper assessment of iPCO2 and pHi as specific measures of the adequacy of gastric mucosal blood flow.

Campylobacter jejuni: clinical and diagnostic value of serum antibody titres

Eighty patients with either bacteriologically confirmed Campylobacter jejuni infection and/or an antibody titre value of at least 1:80, determined by ELISA, were studied. A significant correlation was found between titre value and severity of symptoms (P = 0.015). Although a correlation was noted between symptoms score and endoscopic abnormalities, this was not quite statistically significant (P = 0.053). Comparison of patients with a titre of at least 1:1280 and those with lower titre values revealed a significantly higher symptom score (P = 0.019) and endoscopic score (P = 0.015) in patients with a higher antibody level. By using the previously recommended titre of 1:640 as a cut-off point for active infection, all significant differences were lost. Of 12 patients with positive stool culture, 7 had a titre value of at least 1:1280, suggesting a sensitivity of 58%. However, of 20 patients with negative culture, 4 showed this titre value, three of whom were studied several weeks after the onset of their illness. In those patients with clinically proven Campylobacter infection, the antibody response was characterized by a rapid initial rise and a slow four-fold drop in antibody titre after 3 to 5 months. Colonic involvement of the infection was seen in 63% of our patients with positive cultures. Our results support the conclusion that ELISA is a valuable method of diagnosing C. jejuni infections when stool cultures are likely to become negative, as is the case in prolonged complaints or complications after gastro-enteritis or in proctocolitis or after the use of antibiotics. Serial serum samples have no advantage over a single sample for antibody detection.(ABSTRACT TRUNCATED AT 250 WORDS)