Smoking prevalence and its influence on disease course and surgery in Crohn's disease and ulcerative colitis

BACKGROUND

Smoking demonstrates divergent effects in Crohn's disease (CD) and ulcerative colitis (UC). Smoking frequency is greater in CD and deleterious to its disease course. Conversely, UC is primarily a disease of nonsmokers and ex-smokers, with reports of disease amelioration in active smoking.

AIM

To determine the prevalence of smoking and its effects on disease progression and surgery in a well-characterised cohort of inflammatory bowel diseases (IBD) patients.

METHODS

Patients with smoking data of the Sydney IBD Cohort were included. Demographic, phenotypic, medical, surgical and hospitalisation data were analysed and reported on the basis of patient smoking status.

RESULTS

1203 IBD patients were identified comprising 626 CD and 557 UC with 6725 and 6672 patient-years of follow-up, respectively. CD patients were more likely to smoke than UC patients (19.2% vs. 10.2%, P < 0.001). A history of smoking in CD was associated with an increased proportional surgery rate (45.8% vs. 37.8%, P = 0.045), requirement for IBD-related hospitalisation (P = 0.009) and incidence of peripheral arthritis (29.8% vs. 22.0%, P = 0.027). Current smokers with UC demonstrated reduced corticosteroid utilisation (24.1% vs. 37.5%, P = 0.045), yet no reduction in the rates of colectomy (3.4% vs. 6.6%, P = 0.34) or hospital admission (P = 0.25) relative to nonsmokers. Ex-smokers with UC required proportionately greater immunosuppressive (36.2% vs. 26.3%, P = 0.041) and corticosteroid (43.7% vs. 34.5%, P = 0.078) therapies compared with current and never smokers.

CONCLUSIONS

This study confirms the detrimental effects of smoking in CD, yet failed to demonstrate substantial benefit from smoking in UC. These data should encourage all patients with IBD to quit smoking.

An objective study of acid reflux and cough in children using an ambulatory pHmetry-cough logger

OBJECTIVE

There are no objective ambulatory studies on the temporal relationship between reflux and cough in children. Commercial pHmetry loggers have slow capture rates (0.25 Hz) that limit objective quantification of reflux and cough. The authors aimed to evaluate if there is a temporal association between cough and acid pH in ambulatory children with chronic cough.

DESIGN, SETTING AND PATIENTS

The authors studied children (aged <14 years) with chronic cough, suspected of acid reflux and considered for pHmetry using a specifically built ambulatory pHmetry-cough logger that enabled the simultaneous ambulatory recording of cough and pH with a fast (10 Hz) capture rate.

MAIN OUTCOME MEASURES

Coughs within (before and after) 10, 30, 60 and 120 s of a reflux episode (pH<4 for >0.5 s).

RESULTS

Analysis of 5628 coughs in 20 children. Most coughs (83.9%) were independent of a reflux event. Cough-reflux (median 19, IQR 3-45) and reflux-cough (24.5, 13-51) sequences were equally likely to occur within 120 s. Within the 10 and 30 s time frame, reflux-cough (10 s=median 2.5, IQR 0-7.25; 30 s=6.5, 1.25-22.25) sequences were significantly less frequent than reflux-no cough (10 s=27, IQR 15-65; 30 s=24.5, 14.5-55.5) sequences, (p=0.0001 and p=0.001, respectively). No differences were found for 60 and 120 s time frame. Cough-reflux sequence (median 1.0, IQR 0-8) within 10 s was significantly less (p=0.0001) than no cough-reflux sequences (median 29.5, 15-67), within 30 s (p=0.006) and 60 s (p=0.048) but not within 120 s (p=0.47).

CONCLUSIONS

In children with chronic cough and suspected of having gastro-oesophageal reflux disease, the temporal relationship between acid reflux and cough is unlikely causal.

Who needs colonoscopy to identify colorectal cancer? Bowel symptoms do not add substantially to age and other medical history

BACKGROUND

Many bodies advise that people with bowel symptoms undergo colonoscopy to detect colorectal cancer.

AIM

To determine which bowel symptoms predict cancer on colonoscopy.

METHODS

Information was collected on symptoms, demographics and medical history from patients subsequently undergoing colonoscopy. Multiple logistic regression modelling was used to identify predictors of colorectal cancer. An ROC curve was estimated for each model, and the area under the curve (AUC) was computed.

RESULTS

Cancer was found in 159 patients and no cancer or adenoma in 7577 patients. Bowel symptoms that predicted cancer were rectal bleeding, change in bowel habit and rectal mucus. Prediction was the strongest in patients who had symptoms at least weekly and commencing within the previous 12 months; abdominal pain was predictive only in such patients. The odds ratios never exceeded 4.27. A model based on age, gender, and medical history was highly predictive (AUC = 0.79). Adding symptoms to this model increased the AUC to 0.85.

CONCLUSIONS

This model predicts patients in whom colonoscopy will have the highest yield. Conversely, colonoscopy can be avoided in people at low risk: in our study, 95% of cancers could have been detected by doing only 60% of the colonoscopies.

Clinical trial: the treatment of gastro-oesophageal reflux disease in primary care--prospective randomized comparison of rabeprazole 20 mg with esomeprazole 20 and 40 mg

BACKGROUND

A trial of empirical PPI therapy is usual practice for most patients with symptoms of gastro-oesophageal reflux disease (GERD) in primary care.

AIM

To determine if the 4-week efficacy of rabeprazole 20 mg for resolving heartburn and regurgitation symptoms is non-inferior to esomeprazole 40 mg or 20 mg.

METHODS

In all, 1392 patients were randomized to rabeprazole 20 mg, esomeprazole 20 mg or 40 mg once daily. Patients, doctors and assessors were blinded. Symptom resolution data were collected on days 0-7 and day-28 using the Patient Assessment of Upper Gastrointestinal Disorders Symptom Severity Index with a shortened version used on days 8-27.

RESULTS

Rabeprazole 20 mg was non-inferior to esomeprazole 40 mg for complete resolution of regurgitation and satisfactory resolution of heartburn and regurgitation. For complete heartburn resolution, the efficacy of rabeprazole 20 mg and esomeprazole 40 mg was statistically indistinguishable, although the non-inferiority test was inconclusive. Rabeprazole 20 mg was non-inferior to esomeprazole 20 mg for all outcomes.

CONCLUSIONS

In uninvestigated GERD patients, rabeprazole 20 mg was non-inferior to esomeprazole 40 mg for complete and satisfactory relief of regurgitation and satisfactory relief of heartburn, and not different for complete resolution of heartburn.

The effectiveness of rifabutin triple therapy for patients with difficult-to-eradicate Helicobacter pylori in clinical practice

BACKGROUND

Failure of first line and subsequent Helicobacter pylori eradication therapy is a significant problem and alternative treatments are few.

AIMS

To evaluate the efficacy of a rifabutin-based triple therapy in clinical practice and determine the optimal strategy for its use.

METHODS

Patients referred after first or subsequent treatment failure were prescribed rifabutin triple therapy consisting of standard dose proton pump inhibitor, amoxicillin 1 g and rifabutin 150 mg each b.d. for 10 days.

RESULTS

In 67 patients, the main indications for treatment were dyspepsia (55%), peptic ulcer disease (24%) and increased gastric cancer risk (18%). The median number of previous treatments was 2 (range: 1-9). Eradication of Helicobacter pylori was achieved in 76% (48/63) per protocol and 72% (48/67) on an intention-to-treat basis. When used as second line therapy, 95% (18/19) achieved eradication compared with 68% (30/44) when two or more previous treatments had been used (P = 0.03). Outcome was independent of age, ethnicity, gender or indication for treatment. Adverse events were reported in 10%.

CONCLUSION

Rifabutin triple therapy is a well tolerated and effective second line therapy in the treatment of persistent Helicobacter pylori; however, its efficacy decreases with increasing number of failed previous therapies.

The C-caffeine breath test distinguishes significant fibrosis in chronic hepatitis B and reflects response to lamivudine therapy

BACKGROUND

The 13C-caffeine breath test is a non-invasive, quantitative test of liver function.

AIM

To determine the utility of the 13C-caffeine breath test in chronic hepatitis B virus and its ability to monitor response to lamivudine.

METHODS

Forty-eight chronic hepatitis B virus patients and 24 controls underwent the 13C-caffeine breath test. In 28 patients commenced on lamivudine, 13C-caffeine breath tests were performed at 1 week (n = 12) and after 1 year of therapy.

RESULTS

Patients with Metavir F0-1 fibrosis (2.30 +/- 1.02 Delta per thousand per 100 mg caffeine) had a 13C-caffeine breath test similar to controls (2.31 +/- 0.85, P = 0.96). However, patients with F2-3 fibrosis (1.59 +/- 0.78, P = 0.047) and cirrhotic patients (0.99 +/- 0.33, P = 0.001) had a decreased 13C-caffeine breath test. Fibrosis correlated best with the 13C-caffeine breath test (r(s) = -0.62, P < 0.001). The 13C-caffeine breath test independently predicted significant (F > or = 2) and advanced (F > or = 3) fibrosis and yielded the greatest area under the receiver operating characteristic curve (0.91 +/- 0.04) for predicting advanced fibrosis. The 13C-caffeine breath test was unaltered by 1 week of lamivudine but improved by 61% (P < 0.001) in responders to long-term lamivudine, whereas in those with viraemia and elevated alanine aminotransferase, values remained stable or deteriorated.

CONCLUSION

The 13C-caffeine breath test distinguishes chronic hepatitis B virus-related fibrosis and detects improvement in liver function in response to long-term lamivudine.

Review article: oesophageal complications and consequences of persistent gastro-oesophageal reflux disease

The major oesophageal complications associated with persistent gastro-oesophageal reflux disease (GERD) include erosive oesophagitis, ulceration, strictures and gastrointestinal (GI) bleeding. Although the causes of these complications are uncertain, studies indicate that erosive oesophagitis may progress to the development of ulcers, strictures and GI bleeding. Pharmacological treatment with proton pump inhibitors is favoured over that with H(2)-receptor antagonists for the treatment of strictures. The treatment of strictures is accomplished with dilation and many favour the concomitant use of proton pump inhibitors. Most gastroenterologists are seeing far fewer oesophageal strictures these days since the introduction of proton pump inhibitors. In addition, research has shown that oesophageal complications have a greater impact on patients suffering from night-time GERD than on those suffering from daytime GERD. Barrett's oesophagus is a significant complication associated with persistent GERD and those at risk generally experience a longer duration of symptoms, especially those with a high degree of severity. In addition, there is a strong relationship between Barrett's oesophagus and oesophageal adenocarcinoma. This is in part due to the association of obesity and the development of hiatal hernias. Furthermore, endoscopic screening is being used to detect Barrett's oesophagus and oesophageal adenocarcinoma in persons suffering from chronic GERD, even though screening may not have an impact on outcomes (Sharma P, McQuaid K, Dent J, et al. A critical review of the diagnosis and management of Barrett's esophagus: The AGA Chicago Workshop. Gastroenterology 2004; 127: 310-30.).

Gastro-oesophageal reflux disease and Helicobacter pylori

The interaction between gastro-oesophageal reflux disease (GERD) and Helicobacter pylori (H. pylori) infection has been the subject of intense scrutiny in recent years. Although the evidence base is incomplete it is now sufficient to clarify a number of key questions. H. pylori is not a risk factor for reflux disease. Similarly, H. pylori infection, in most patients, is not ''protective'' against the risk of developing reflux and oesophagitis. Furthermore, reflux and oesophagitis are not more likely to develop or to worsen after H. pylori eradication therapy and eradication does not make control of reflux symptoms with proton pump inhibitor (PPI) therapy more difficult. Long term PPI therapy in the presence of H. pylori infection does increase the rate at which gastric mucosal atrophy and intestinal metaplasia develop. Eradication therapy has been shown to reduce this risk. In the uninfected stomach, PPIs are associated with a low likelihood of these adverse histological changes. PPI therapy reduces the accuracy of diagnostic tests for H. pylori. The decision to test for and treat H. pylori infection in the context of reflux must be individualised based on patient factors including co-morbidity, age, gastric histology, family history and informed choice. Distinction must be made between treating symptoms and potentially reducing risks. A decision not to test for and treat H. pylori is now just as active a choice as is the decision to test and treat. Recent international consensus statements recommend eradication of H. pylori prior to long term PPI therapy in reflux disease, although there is not a universal agreement on this. Further research to clarify the risk and benefits of such an approach is required.

Chest pain. Differentiating GIT from cardiac causes

BACKGROUND

Chest pain is a common presenting symptom in general practice. Although a cardiac cause is not the commonest origin, a high index of suspicion is needed. When the diagnosis is not clear, a cardiac cause should be considered until proven otherwise. A gastrointestinal origin of chest pain is not infrequent and may be due to oesophageal, gastric or biliary disease. Oesophageal causes are most common and include reflux, hypersensitivity or dysmotility.

OBJECTIVE

This paper reviews the main gastrointestinal causes that may present with acute chest pain.

DISCUSSION

Clinical history taking is the key to decision making and guides the choice of prompt or routine investigation or a therapeutic trial. When reflux is suspected as the cause, a therapeutic trial of high dose antisecretory therapy is appropriate. Investigations may be helpful when typical reflux symptoms are not present or there is a poor response to this approach. Investigations may include endoscopy, ambulatory pH monitoring, barium swallow or oesophageal manometry.

Randomized trial of omeprazole and metronidazole with amoxycillin or clarithromycin for Helicobacter pylori eradication, in a region of high primary metronidazole resistance: the HERO study

BACKGROUND

The efficacy of omeprazole-based eradication therapies has been determined mostly in populations with low to moderate prevalence of metronidazole resistant Helicobacter pylori, yet resistance is high in many regions.

AIM AND METHODS

The H. pylori eradication and duodenal ulcer healing rates after 1 week of either omeprazole 40 mg mane, amoxycillin 500 mg t.d.s. and metronidazole 400 mg t.d.s. (OAM) or omeprazole 20 mg b.d., metronidazole 400 mg b. d. and clarithromycin 250 mg b.d. (OMC) were compared in a randomized trial in Australia and New Zealand. Patients had a further 1 week of omeprazole 20 mg. Outcome was assessed at 6 weeks with stringent criteria (endoscopy, biopsies and 13C-urea breath test).

RESULTS

Of 220 subjects randomized, the H. pylori eradication rates (all patients treated/per protocol) were 82%/85% for OMC and 58%/63% for OAM (P= 0.001). Pre-treatment metronidazole resistance was present in 56% and clarithromycin resistance in 6%. The eradication rate for primary metronidazole resistance isolates treated with OMC was 80% (CI: 65-90%) compared with 45% (CI: 29-62%) for OAM, whereas for sensitive organisms, the eradication rates were 94% (CI: 79-99%) and 79% (CI: 62-91%), respectively. Duodenal ulcer healing was 96% for OMC and 87% for OAM. Compliance was excellent and both treatments were well-tolerated.

CONCLUSIONS

OMC is a well-tolerated, effective therapy for H. pylori eradication and duodenal ulcer healing in this region despite the high metronidazole resistance rate. OAM is less effective, largely due to the impact of metronidazole resistance.

Aspartate aminotransferase: alanine aminotransferase ratio in chronic hepatitis C infection: is it a useful predictor of cirrhosis?

BACKGROUND

The clinical usefulness of the ratio of serum aspartate aminotransferase (AST) to alanine aminotransferase (ALT) has been explored in several liver disorders. It has been suggested that in patients with chronic hepatitis C virus (HCV) infection an AST:ALT > or = 1 has 100% specificity and positive predictive value in distinguishing cirrhotic from non-cirrhotic patients. Such statistical certainty attached to a simple biochemical test merits further evaluation. The present study, therefore, assessed the AST:ALT in patients with chronic HCV infection to determine the validity of the ratio in predicting cirrhosis and to correlate the ratio with the histological grade of necroinflammatory activity and fibrosis.

METHODS

A retrospective analysis of 153 patients with chronic HCV infection was conducted. Serum biochemistry had been obtained within a mean of 4 weeks of liver biopsy. The histology was scored in terms of activity and fibrosis as described by Scheuer and correlated with AST:ALT.

RESULTS

In 30 patients with cirrhosis, the mean AST:ALT (0.99 +/- 0.06) was higher than in 123 patients without cirrhosis (0.60 +/- 0.02; P < 0.001). A ratio > or = 1 had 95.9% specificity and 73.7% positive predictive value in distinguishing cirrhotic from non-cirrhotic patients, with a 46.7% sensitivity and 88.1% negative predictive value. The ratio also parallelled the Scheuer score with respect to fibrosis but not with respect to inflammation.

CONCLUSION

Although relatively insensitive, an AST:ALT > or = 1 is highly specific but not diagnostic for the presence of cirrhosis in patients with chronic HCV infection. The ratio reflects the grade of fibrosis in these patients.

Treating Helicobacter pylori

BACKGROUND

The treatment for Helicobacter pylori infection has changed continuously during the past decade and recommended treatments have not always been readily available in primary care. These factors have contributed to confusion and considerable variation in prescribing.

OBJECTIVE

This short review outlines the key aspects of current treatment of H pylori.

DISCUSSION

With the advent of single script, effective therapies, there should be more uniformity in treating this common infection. With appropriate choice of therapy and patient counselling to maximise compliance, excellent H pylori eradication rates are achievable in general practice.

The effect of dosing with omeprazole on the accuracy of the 13C-urea breath test in Helicobacter pylori-infected subjects

BACKGROUND

The 13C-urea breath test (13C-UBT) is an accurate means of Helicobacter pylori diagnosis. However, proton pump inhibitors may suppress H. pylori and cause false negative results.

AIM

To study the kinetics of H. pylori suppression by omeprazole during and after short-term use.

METHODS

Volunteers underwent a baseline 13C-UBT (13C-urea 100 mg). H. pylori-positive subjects took omeprazole 20 mg daily for 14 days. Those who remained 13C-UBT positive (delta13CO2 >/= 5) continued omeprazole for a further 14 days. 13C-UBTs were performed weekly on omeprazole and then every second day after it was stopped. False negatives occurred when delta13CO2 fell to < 5.

RESULTS

In 25 H. pylori-positive subjects (mean age 43.9 +/- 2.4 years; 21 females, 4 males) the mean baseline delta13CO2 was 28.1 +/- 3.4. False negative breath tests occurred in three subjects after 7 days of omeprazole and in a further four subjects after 14 days. A further six subjects developed negative tests between Days 14 and 28. Following cessation of omeprazole, the 13C-UBT became positive again in 12/13 subjects within 4 days and in all within 6 days, with a mean recovery to 99.9 +/- 18.6% of baseline delta13CO2.

CONCLUSIONS

False negative 13C-UBTs are common during treatment with omeprazole and occur after as little as 7 days. Return to positive test results is rapid after cessation of omeprazole. These findings are relevant to the timing of testing in clinical practice.

The impact of short-term ranitidine use on the precision of the 13C-urea breath test in subjects infected with Helicobacter pylori

BACKGROUND

The 13C-urea breath test (13C-UBT) is a very accurate method of Helicobacter pylori diagnosis with a false-negative rate of 1-3%. However, the accuracy of the 13C-UBT is affected by potent acid inhibition with proton-pump inhibitors, which may suppress H. pylori and cause false-negative results. It is not known whether this occurs with less potent acid inhibition by H2-antagonists and any effect may be important clinically.

OBJECTIVE

To determine the kinetics of 13CO2 excretion in H. pylori infected subjects during and after short-term ranitidine use.

METHODS

Volunteers underwent a baseline 13C-UBT (positive: delta13CO2 > or = 5.0; negative: < or = 3.5; indeterminate: > 3.5 to < 5.0). Infected subjects took ranitidine 300 mg each evening for up to 28 days. 13C-UBTs were performed at weekly intervals and then every other day after ranitidine was ceased. If the 13C-UBT remained positive after 14 days, ranitidine was continued for a further 14 days.

RESULTS

Thirty-one subjects were studied (mean age 40.4 +/- 2.1 years; 23 female/8 male; mean baseline delta13CO2 27.3 +/- 2.5). In 28 subjects the 13C-UBT remained positive during ranitidine use. The mean delta13CO2 rose to 124% (P< 0.06) and 121% (P < 0.05) of baseline at 14 and 28 days respectively. In two subjects, the delta13CO2 became indeterminate at day 7 (delta13CO2 4.3 and 3.8). In one of these, return to a positive value (delta13CO2 13.6; 103% of baseline) occurred while still on ranitidine. The other subject became positive again by day 3 off ranitidine (17.8; 119% of baseline). One subject had a transiently negative test after 21 days and this became positive again while still taking ranitidine.

CONCLUSIONS

Ranitidine has a minimal effect on the 13C-UBT. The rate of indeterminate or false-negative tests is no greater than in patients on no anti-secretory medication.

Idiopathic localized dilatation of the ileum. A rare cause of gastrointestinal haemorrhage in an adult

A case of idiopathic localized dilatation of the ileum presenting in adulthood and associated with small bowel malrotation, ulceration and bleeding is described. To our knowledge, this is the first such report of this combination of features. The diagnosis was made using a small bowel barium study and intra-operative enteroscopy. Idiopathic localized dilatation of the ileum with ulceration should be considered as a rare small intestinal cause of occult or frank gastrointestinal blood loss in children or young adults.

Prevalence and demographic determinants of metronidazole resistance by Helicobacter pylori in a large cosmopolitan cohort of Australian dyspeptic patients

BACKGROUND

The pre-treatment sensitivity of Helicobacter pylori to metronidazole is a key determinant of successful eradication therapy and should influence local choice of therapy. However, there are few data defining the prevalence of metronidazole resistance (MR) in Australia.

AIM

To determine prospectively the prevalence and demographic determinants of MR in H. pylori isolates from a large and cosmopolitan cohort of dyspeptic patients in Sydney.

METHODS

Consecutive dyspeptic patients undergoing endoscopy had gastric biopsies for histology, urease test and culture. Metronidazole resistance was determined by E-test after subculture. An MIC > 8 micrograms/mL defined MR. Patient age, gender, birthplace and history of previous nitroimidazole use were recorded.

RESULTS

In 732 patients, H. pylori was present in 46.4%. Culture was successful in 81% and subculture for MR in 88% of these. In 237 evaluable patients the overall MR rate was 59.1%. Five patients had had prior triple therapy for H. pylori (of which four of five had MR). Therefore, the primary MR rate in the study population was 58.6% (136/232). MR was more prevalent in younger patients (p = 0.0002). The MR rate was 70.4% in patients 18-39 years, 66.7% in those aged 40-59 years and lowest (38.9%) in those 60 years or older (p = 0.002). The MR rate was highest in patients born in Southeast Asia (72.8%, 59/81) and significantly higher than in Australian born (48.1%, 26/54), or Southern European (46.2%, 24/52) born patients (p = 0.002). There was no gender difference. Logistic regression to determine the impact of each variable (birthplace, age and gender) on MR identified Southeast Asia birthplace as a factor associated with greater likelihood of harbouring an MR isolate (OR 1.88, p = 0.02). Southern European born patients had the lowest risk of MR (OR 0.70, p = 0.02) as did patients older than 60 years (OR 0.56, p = 0.04). A definite history of prior metronidazole use was infrequent and not predictive of MR.

CONCLUSIONS

While a high rate of MR is not unexpected in patients born in developing countries, the high rate in Australian born patients is surprising and of concern. This may relate to the high local usage of nitroimidazoles as monotherapy and has important implications for the effectiveness of metronidazole containing triple therapies.

The relation between gastric vitamin C concentrations, mucosal histology, and CagA seropositivity in the human stomach

BACKGROUND

Vitamin C may be protective against gastric cancer though infection with Helicobacter pylori is associated with a reduction in intragastric concentrations of vitamin C.

AIMS

To examine the effects of H pylori infection, gastric juice pH, the severity and extent of gastric inflammation, and CagA antibody status of the individual on gastric juice and mucosal vitamin C concentrations.

PATIENTS

One hundred and fifteen patients undergoing routine gastroscopy for investigation of dyspepsia.

METHODS

High performance liquid chromatography was used to determine vitamin C concentrations. CagA antibody was detected by western blot analysis.

RESULTS

Gastric juice ascorbic acid concentration was significantly lower in patients infected with H pylori compared with those uninfected (19.3 mumol/l (interquartile range (IQR) 10.7-44.5) versus 66.9 mumol/l (IQR 24.4-94.2), p = 0.003). The reduction in gastric juice ascorbic acid concentration was inversely related to the severity of gastritis (p = 0.01). CagA positive patients had significantly lower gastric juice ascorbic acid concentrations than CagA negative ones (14.8 mumol/1 (IQR 7.9-52.2) versus 39 mumol/l (IQR 19.9-142.2), p = 0.05). Decreased gastric juice dehydroascorbic acid concentrations were observed in patients with gastric atrophy and intestinal metaplasia. Mucosal ascorbic acid concentrations were also significantly lower in infected patients than uninfected patients (p = 0.04).

CONCLUSIONS

The reduction in gastric vitamin C concentrations is related to gastric juice pH, the severity and extent of gastritis, the presence of H pylori, and the CagA antibody status of the individual. These findings may have implications in H pylori associated carcinogenesis.

Ornithine decarboxylase activity is a marker of premalignancy in longstanding Helicobacter pylori infection

BACKGROUND

Longstanding Helicobacter pylori infection may increase the risk of developing gastric adenocarcinoma. The sequence of chronic active gastritis leading to gastritis with atrophy and subsequent intestinal metaplasia is thought to be a key step in gastric carcinogenesis. Ornithine decarboxylase (ODC) activity is increased in some pre-malignant gastrointestinal conditions and is essential for malignant transformation in vitro.

AIMS

To measure ODC activity in the antrum of H pylori infected and non-infected subjects and to relate this to histological abnormalities associated with recent and longstanding H pylori infection.

METHODS

Six antral mucosal biopsy specimens were obtained from 75 patients for detailed histological assessment and measurement of ODC activity. Samples were measured in duplicate and results expressed as median, interquartile range in pmol/mg protein/h.

RESULTS

ODC activity was significantly higher in H pylori positive (164, 88-259 pmol/mg/h) than H pylori negative subjects (99.8, 55-158 pmol/mg/h, p = 0.003). However the presence of gastritis, irrespective of the severity of inflammation or activity had no influence on ODC activity. Gastritis with atrophy was associated with increased ODC activity, which was closely related to the severity of the atrophy (p = 0.01). Similarly, ODC activity was significantly increased in subjects with intestinal metaplasia (196, 83-25) compared with those without intestinal metaplasia (111.7, 65-175, p < 0.04).

CONCLUSIONS

These results indicate that the histological changes associated with longstanding H pylori infection rather than inflammation alone are associated with increased polyamine biosynthetic activity. This may be relevant to H pylori associated gastric carcinogenesis.

Increased energy expenditure in growing adolescents with Crohn's disease

Undernutrition is considered to have a central role in the pathogenesis of growth retardation in Crohn's disease. This may occur as a consequence of inadequate food intake, increased energy expenditure, or both. Ten growing adolescents with inactive Crohn's disease were assessed with respect to anthropometric parameters and resting energy expenditure, measured by indirect calorimetry during remission, repeated in relapse (N = 5), and compared to that predicted from the Harris-Benedict formula. Mean energy intake was assessed with seven-day diaries in five patients and compared to recommended intake for age, sex, weight, and physical activity. Ten healthy, growing, age- and sex-matched adolescents served as controls. Nine patients with inactive Crohn's disease, who had ceased growing, were matched for disease site and duration and acted as disease controls. Patients and disease controls had lower body mass index (19.2 +/- 0.6; 20.9 +/- 0.7) than healthy controls (23.7 +/- 0.6; P < 0.001). Percent body fat was lower in patients (13.2 +/- 1.9%) compared to healthy controls (20.5 +/- 2.4%; P < 0.05) but not to disease controls (17.0 +/- 2.6%). Patients had higher resting energy expenditure per kilogram of fat-free mass than disease or healthy controls (36.9 +/- 5.1; 32.9 +/- 2.6; 30.9 +/- 2.1 kcal; P < 0.02). Measured resting energy expenditure in patients, but not in disease or healthy controls, was higher than the predicted (measured: predicted 1.15, 1.03, 0.9, respectively; P < 0.03). Energy intake in patients was 97% of recommended intake but the measured ratio of energy intake/resting energy expenditure was lower than the predicted ratio (1.49 vs 1.71; P < 0.05). During subsequent relapse in five patients resting energy expenditure was unchanged. In growing adolescents with inactive Crohn's disease, there is increased energy expenditure that is not accompanied by an increase in energy intake. Relapse of disease does not appear to increase resting energy expenditure further but may "divert" energy from growth to disease activity. This suggests that nutritional therapy should be directed towards increasing caloric intake to maximize growth potential.

Do commercial serological kits for Helicobacter pylori infection differ in accuracy? A meta-analysis

OBJECTIVES

To compare the accuracy of common commercial serological kits for Helicobacter pylori and to ascertain factors affecting accuracy.

METHODS

A comprehensive MEDLINE and manual search strategy was used to identify all articles comparing two or more kits. Each article was critically appraised for sample characteristics, study design, and data handling. The data comparing accuracy of the kits was analyzed by standard statistical methods as well as summary receiver operator characteristic curves (sROCs). A sROC also was used to estimate overall test accuracy and to identify factors affecting the measurement of accuracy.

RESULTS

The 21 studies identified were of varying quality, but our analyses suggested that different commercial kits did not have significantly different accuracy. Overall, at a sensitivity of 85%, specificity was estimated to be 79%. Test accuracy measured was significantly higher in studies with smaller proportions of infected patients.

CONCLUSIONS

There is little evidence in the literature to suggest that any one of the common commercial serological kits is more accurate than any other. The overall accuracy of these kits may not be adequate for clinical decision-making in all patient groups.

Probiotic control of diarrhoeal disease

Probiotics have been suggested to be of use in many diarrhoeal disorders, particularly in the prophylaxis and treatment of infectious diarrhoea. Several different preparations are available commercially and they are widely used but consistent scientific documentation of their efficacy is lacking. Although their putative mode of action is not known, non-pathogenic organisms may prevent or displace enteropathogens from colonising the gut. In vitro studies suggest that some probiotics may exert a direct inhibitory effect on pathogenic organisms. There is some clinical evidence suggesting a possible role for probiotics in the prophylaxis of infectious diarrhoea in some circumstances, but there is little evidence of a beneficial effect in the treatment of established diarrhoea, except in cases of relapsing C. difficile infection. There are no convincing data at present demonstrating efficacy of probiotics in non-infective diarrhoeal disorders. Although the use of probiotics in diarrhoeal diseases is conceptually appealing, their use for this indication is not clearly supported by the available scientific literature at present. Further research into the role of the human microflora in diarrhoeal diseases is needed to aid the selection of appropriate non-pathogenic bacteria for clinical studies. Well conducted controlled clinical trials are then needed in order to determine the place of probiotics in the prevention and treatment of diarrhoeal disorders.

Attachment of Giardia lamblia trophozoites to a cultured human intestinal cell line

Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonisation of the small intestine and is considered a prerequisite for giardia induced enterocyte damage. The precise mechanisms involved are still being debated and some earlier work has been performed in models of uncertain biological relevance. In this study, co-incubation of giardia with enterocyte-like differentiated Caco-2 cells was used as a model to study the influence of physical and chemical factors on attachment. Giardia attachment was maximal between one and eight hours and stable over pH 7.2-8.2 but it was reduced by acidification. Attachment was dependent on temperature and was maximal at 37 degrees and virtually abolished at 4 degrees C. It was reduced compared with controls (p < 0.05) by EDTA 2.5 mM (mean (SEM) 32 (4)%), colchicine 12.5 microM (35 (5)%), mebendazole 10 micrograms/ml (30 (3)%), and cytochalasin B 1 microgram/ml (34 (3)%). Giardia attachment was also diminished by preincubation with mannose 50 mM or mannose-6-phosphate 35 mM (21 (4); 17 (5)%) or by preincubating Caco-2 cells with concanavalin A 100 micrograms/ml (19 (2)%). Enhanced binding was not evident after trypsinisation of trophozoites. Scanning electron microscopy showed that giardia seemed to attach to the Caco-2 monolayer predominantly by its ventral surface but dorsal orientation was also observed. No difference in attachment was observed between three different giardia isolates or a parent isolate and its clone. Attachment of giardia to Caco-2 cells is primarily by cytoskeletal mechanisms, inhibitable by interference with contractile filaments and microtubules, while attachment by mannose binding lectin also seems to mediate binding.

A randomized prospective comparison of clarithromycin versus amoxycillin in combination with omeprazole for eradication of Helicobacter pylori

AIM

To compare H. pylori eradication rates using omeprazole in conjunction with either amoxycillin or clarithromycin.

BACKGROUND

Omeprazole with amoxycillin is the most widely used dual therapy regimen for eradication of H. pylori. A recent open study suggested a high eradication rate combining omeprazole with the newer macrolide, clarithromycin.

METHODS

A randomized prospective trial in 54 patients was conducted to compare 2 weeks of treatment with omeprazole 40 mg once daily and either amoxycillin 500 mg three times daily or clarithromycin 500 mg three times daily. H. pylori eradication was assessed using the 13C urea breath test.

RESULTS

Eradication was achieved in 18/26 (69.2%) of subjects treated with omeprazole and amoxycillin and 18/25 (72.0%) of those treated with omeprazole and clarithromycin (P = N.S.). Minor side effects, most commonly altered taste, were reported by 16% of patients and were more frequent in those randomized to clarithromycin (P = 0.01).

CONCLUSIONS

These regimens are similarly effective. However, clarithromycin is more expensive, associated with a greater frequency of side effects and, unlike amoxycillin, resistance by H. pylori has been reported. This suggests that clarithromycin may be a useful alternative when there is penicillin allergy or previous treatment failure, but it should not replace amoxycillin as first choice in omeprazole-based dual therapy.

Traveler's diarrhea: clinical presentation and prognosis

Traveler's diarrhea is usually a short, self-limiting illness lasting on average 3-5 days. The illness may present either as (1) acute watery diarrhea, (2) diarrhea with blood (dysentery) or (3) chronic diarrhea, often with clinical evidence of fat or carbohydrate malabsorption. The majority of cases of traveler's diarrhea are due to intestinal infection and resolve without specific treatment. Antibiotics can reduce the severity and duration of the illness and are always indicated for dysenteric shigellosis and amoebiasis. Oral rehydration therapy is the mainstay for managing water and electrolyte depletion.

Genotypic heterogeneity within Giardia lamblia isolates demonstrated by M13 DNA fingerprinting

There has been considerable speculation regarding the possible relationship between the phenotypic and genotypic heterogeneity seen among human isolates of Giardia lamblia and the wide clinical spectrum of human giardiasis. Several workers have suggested that human giardiasis may be a mixed infection consisting of variant strains or subgroups which are present in the same infection and which are selectable, but it is not clear whether these apparent variant strains represent a truly heterogeneous infection or whether the genotypic heterogeneity observed is due to the susceptibility of the Giardia genome to a high rate of structural genetic rearrangement. We have therefore studied variation in Giardia intestinalis genotypes in 19 isolates in vitro and in vivo by using the technique of M13 DNA fingerprinting. Genotypes of isolates changed with time when cultured under standard conditions and when pressured with bile. Sequential isolates and their clones taken from a patient with chronic giardiasis both before and after several treatments with metronidazole had different genotypes. Finally, clones of isolate WB had different initial genotypes, which changed after 4 months in culture. These findings suggest that the apparent genotypic heterogeneity at least in these G. intestinalis isolates is more likely to be due to the plasticity of the Giardia genome than to the presence of a truly mixed population of strains within the same infection.

Activity of metronidazole, azithromycin and three benzimidazoles on Giardia lamblia growth and attachment to a human intestinal cell line

BACKGROUND

Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for Giardia-induced enterocyte damage. Inhibition of attachment may therefore have therapeutic potential.

METHODS

Enterocyte-like differentiated Caco-2 cells were used as a biologically appropriate attachment surface to determine the effect of three benzimidazole compounds (albendazole, mebendazole and thiabendazole), azithromycin and metronidazole on Giardia attachment. The results were compared with the ability for each drug to inhibit Giardia growth, measured using [3H]-thymidine uptake.

RESULTS

The benzimidazoles inhibited Giardia attachment at much lower concentrations than did metronidazole. However, metronidazole was a much more potent inhibitor of growth than any of the benzimidazoles. Azithromycin did not significantly impair Giardia attachment or growth. The benzimidazoles decrease attachment but are less giardiacidal than metronidazole.

CONCLUSION

This model appears useful for testing potential antigiardial compounds and investigating mechanisms of drug action.

Effect of age, Helicobacter pylori infection, and gastritis with atrophy on serum gastrin and gastric acid secretion in healthy men

Gastric acid secretion has been considered to decline with increasing age but this view is being re-evaluated as the importance of Helicobacter pylori infection emerges. This study aimed to determine the effect of age, H pylori, and gastritis with atrophy on the serum gastrin concentration, gastric secretory volumes, and acid output in healthy, asymptomatic men. Young men (mean (SD) age 22.9 (0.6) years; n = 22) were compared with old men (72.9 (1.2) years; n = 28) in respect of basal serum gastrin and basal, sham fed, pentagastrin stimulated maximal and peak acid secretion. Antral, corpus, and fundal biopsy specimens were taken for histology and H pylori status (histology, culture, and rapid urease test). H pylori associated gastritis was present in three of 22 young (13.6%) and 16 of 28 old (57.1%) men. Gastritis with atrophy was present in 11 old subjects, 10 of whom were H pylori positive. These subjects had higher mean (SD) serum gastrin concentrations than old subjects without atrophy and young subjects (61.8 (9.2); 40.0 (2.9); 36.8 (2.3) pmol/l respectively; p < 0.001). H pylori infected subjects had higher gastrin values than uninfected subjects, overall (55.3 (5.9); 36.0 (1.8) pmol/l; p < 0.001) and in subjects without atrophy (45.3 (4.2); 36.0 (1.8) pmol/l; p < 0.03). In subjects without H pylori infection, gastrin values did not differ with age (old 37.1 (1.7); young 35.4 (2.1) pmol/l). The maximal gastric secretory volume was lower in old subjects with atrophy. Acid output (mmol/h) in subjects with atrophy was lower than in subjects with no atrophy (basal: 3.0(1.1); 5.1(0.7); p=NS; sham led: 5.4 (1.4); 9.3 (0.8); p<0.02; maximal: 18.9 (4.0); 31.4(1.8); p<0.002; peak: 25.1(5.3); 43.4(2.7); p<0.003). However, acid secretion in old subjects without atrophy was not different to that in young subjects, irrespective of H pylori status. These results did not differ when acid output was expressed as mmol/h/kg lean body mass or mmol/h/kg fat free body weight. Using multiple linear regression analysis, gastritis with atrophy was the only factor that had an independent negative effect on acid secretion. In healthy men without atrophy, gastric acid secretion is preserved with ageing and is independent of H pylori status. Atrophy, which is closely related to H pylori infection, is associated with a decline in acid secretion. Increased basal serum gastrin is related to both atrophy and H pylori infection but not to ageing per se.

Field evaluation of a rapid, simple and inexpensive urease test for the detection of Helicobacter pylori

A modified rapid urease test (MRU test) for the detection of Helicobacter pylori was evaluated under field conditions during an endoscopic survey in rural India and compared with a commercially available urease test (CLO test) and with histology. Of 195 consecutive subjects who underwent upper gastrointestinal endoscopy, 153 (78.5%) were positive for Helicobacter pylori when tested by the CLO test and/or histology. The sensitivity and specificity of the MRU test relative to this was 97.4 and 95.2%, respectively when the test was read over a 3 h period. The MRU test was positive in 77.4, 89.0, 93.8 and 96.6% of cases at 1, 5, 20 and 60 min, respectively, compared with 2.7, 14.4, 48.6 and 71.2% of cases for the CLO test at the same time. The accuracy of the MRU test was thus similar to that of other methods for the detection of Helicobacter pylori. Furthermore, it gave a positive diagnosis more rapidly than other tests, in most cases before the subject had left the endoscopy suite. The MRU test is extremely simple to prepare and read and costs less than 0.05 pounds per test compared with 2.26 pounds for a CLO test. It is suitable for use in clinical or epidemiological work and especially where cost factors are critical.

Dyspepsia, Helicobacter pylori, and peptic ulcer in a randomly selected population in India

There seems to be a worldwide geographic variation in the prevalence of peptic ulcer disease, although there are few reliable population based studies. This study aimed to determine the prevalence of peptic ulcer disease in a community in southern India and to evaluate the relationship between dyspeptic symptoms, Helicobacter pylori infection, gastritis, and peptic ulcer disease. A sample population was selected randomly from a rural monastic settlement in southern India. Subjects were interviewed using a standardised symptom and demography questionnaire then underwent upper endoscopy and antral biopsy for histology and CLO rapid urease test. Altogether 197 subjects from a population of 1499 (13.1%) were studied. All were male monks and ethnically Tibetan. The median age was 28 years (range: 21-81). None smoked or took NSAIDs. The six month period prevalence of dyspeptic symptoms was 68.5%. Current symptoms were present in 58.9% of subjects. Dyspepsia was more common in subjects aged 40 years or younger (p < 0.0001). H pylori was detected in 77.2% subjects. There was no association between dyspepsia and the presence of H pylori or histological gastritis, although there was a strong correlation between symptoms and ulcer (p < 0.003). The point prevalence of active peptic ulcer was 6.6% (13/197). All ulcers detected were either prepyloric or pyloroduodenal in location. A further 6.6% of subjects had definite evidence of scarring or deformity indicative of ulceration in the past. Subjects with past or present ulcers comprised 17.8% of dyspeptic subjects. H pylori was present in all subjects with active ulcers and in 12/13 of those with scarring. Dyspepsia, H pylori infection, gastritis, and peptic ulcer are all more common in this population than in those from developed countries. Ulcer disease, however, accounts for only a small proportion of subjects with symptoms and neither H pylori infection nor gastritis are significantly associated with the presence of dyspepsia.

Pleuropulmonary complications of fine bore naso-enteric feeding tubes

Fine bore naso-enteric feeding tubes are commonly used for enteral alimentation. Although regarded as generally safe, complications associated with their use occur. Case reports presented here highlight the potential hazards of these tubes. Pleuropulmonary complications are reviewed and guidelines suggested for the safe insertion of such tubes.

Fulminant hepatic failure

Most cases of fulminant hepatic failure (FHF) are related to viral hepatitis or to drugs and toxins. With improvement in supportive intensive care, the overall survival has increased, but specific forms of temporary hepatic support pending hepatic regeneration have been disappointing. With the widespread availability of orthotopic liver transplantation, this has become a viable option for those patients with FHF who are unlikely to survive with conservative treatment, although patient selection and timing of transplantation still presents a clinical dilemma.

Prediction of postoperative complications by clinical and nutritional assessment

This study evaluated a battery of nutritional measures and pre-operative clinical assessment as predictors of postoperative morbidity. Fifty-seven consecutive patients about to undergo major elective abdominal or thoracic surgery were surveyed. Thirty-two per cent of patients had three or more abnormal measurements of nutritional indices. Thirty patients had a total of 52 complications and in 12 patients these were major. The Prognostic Nutritional Index (PNI), formulated by Mullen, was found to be the best predictor of postoperative outcome. It identified 10 of 12 (83%) patients who subsequently developed major complications with a specificity of 73%. Clinical assessment selected six of the 12 patients who developed major complications.