High-performance liquid chromatographic method for the simultaneous detection of the adulteration of cereal flours with melamine and related triazine by-products ammeline, ammelide, and cyanuric acid.

Melamine has been used for the adulteration of cereal flours in order to increase their apparent protein content. Crude melamine may contain several by-products, i.e. ammeline, ammelide, and cyanuric acid. The simultaneous analysis of all four chemicals is difficult because of the formation of an insoluble salt between melamine and cyanuric acid. A simple and convenient high-performance liquid chromatography (HPLC) method for the detection of the adulteration of cereal flours with all four chemicals is proposed herein. The precipitate formation between melamine and cyanuric acid was prevented by using alkaline conditions (pH 11-12) for both standards preparation and sample extraction. The method uses matrix-matching, which involves the construction of a calibration curve on a blank (negative control) matrix, which is then used for the quantitation of melamine and by-products in adulterated (positive) samples. Matrix-matching compensates for analyte losses during sample preparation, and for matrix effects. The method was successfully applied to wheat, corn, and rice flours, and is expected to be applicable (with some modifications) to soy flour as well. The method allows for the detection of melamine, ammeline, and ammelide at approximately 5 microg g(-1), and cyanuric acid at approximately 90 microg g(-1) in wheat flour.

Trace analysis of perchlorate anion in selected food products by reverse-phase liquid chromatography-tandem mass spectrometry.

An alternative, rapid, and reproducible method of analysis for perchlorate in selected food products (fruit and vegetable juice, milk, and bottled water) was developed and validated. Improvements over previous methods were achieved by the use of a rugged and inexpensive C18 column, a multi-mode OASIS HLB solid-phase extraction cartridge for sample clean-up, and acetic acid for pH adjustment and protein precipitation. The hydrophobicity of the perchlorate anion gives it good retention and separation characteristics on C18 chromatographic columns. The C18 column allowed for the use of 90% of acetonitrile at a low flow rate (0.3 ml min(-1)), without splitting, and could also be regenerated with organic solvents, unlike an ion-exchange column. Perchlorate levels in selected commercial food samples were: <1.0-2.1 ng g(-1) (fruit and vegetable juices, reported here for the first time), <1.0-5.0 ng g(-1) (milk), and <1.0 ng g(-1) (bottled water).

Intragastric maldistribution of a liquid meal in children with recurrent abdominal pain assessed by three-dimensional ultrasonography.

BACKGROUND: Using two-dimensional (2D) ultrasonography, we previously found indications of impaired adaptive relaxation of the proximal stomach in children with recurrent abdominal pain (RAP). In the present study, we applied a new three-dimensional (3D) ultrasonographic method to investigate intragastric volumes and distribution of a liquid meal in another group of children with RAP. METHODS: Twenty patients with RAP (age 10-15 years) and 20 healthy subjects (age 11-15 years) underwent ultrasonographic measurements of the stomach. A position sensor was used based on magnetic scanhead tracking for acquisition of 3D images after a liquid meal. The children scored abdominal symptoms before and after the meal. RESULTS: Expressed as a fraction of ingested volume, the patients had a smaller volume of the proximal stomach and a larger antral volume at 2 min postprandially compared to healthy subjects (P = 0.03 and P = 0.001, respectively). The patients also showed a decreased proximal to distal gastric volume ratio at 2 min postprandially (P = 0.001). Patients experienced more pain in response to the meal than healthy subjects (P = 0.04), but there was no correlation between pain and proximal or distal gastric volumes. CONCLUSIONS: RAP in children may be associated with an early intragastric maldistribution of a meal.

Eradication of Helicobacter pylori does not increase acid reflux in patients with mild to moderate reflux oesophagitis.

BACKGROUND: A substantial minority of patients with gastro-oesophageal reflux disease (GERD) are infected with Helicobacter pylori, but there is controversy as to whether these patients should be treated for their infection. We hypothesized that H. pylori eradication increases gastro-oesophageal acid reflux in such patients with time. METHODS: Thirty-five consecutive H. pylori-infected patients (16 M and 19 F) with mild or moderate reflux oesophagitis were enrolled. Twenty-four-hour intra-oesophageal (n = 35) and intragastric (n = 12) pH-metry was recorded before and 15 months after H. pylori eradication. Gastric biopsy specimens from the antrum and corpus were obtained from 10 consecutive patients before and 15 months after H. pylori eradication. RESULTS: Fifteen months after eradication of H. pylori there was a significant decrease in percentage time oesophageal pH < 4 in the recumbent position only (P = 0.04). Despite a marked reduction in the severity of gastritis, there was no significant change in gastric acidity, total intra-oesophageal acid exposure or symptom score. Heartburn improved in 12, worsened in 7. and remained unchanged in 16 patients (P = 0.36) without any significant relationship to individual changes in acid exposure (P = 0.60). CONCLUSIONS: H. pylori eradication does not increase gastric acidity or gastro-oesophageal acid reflux in patients with mild to moderate reflux oesophagitis over the first 15 months.

Intragastric maldistribution of a liquid meal in patients with reflux oesophagitis assessed by three dimensional ultrasonography.

BACKGROUND AND AIMS: Our aim was to study intragastric volume and distribution of a liquid meal in patients with reflux oesophagitis using three dimensional ultrasonography. METHODS: Twenty patients and 20 healthy controls underwent ultrasonographic measurements of the stomach using a position sensor based on magnetic scanhead tracking for acquisition of three dimensional images. In vivo accuracy of the method was evaluated by scanning a soup filled barostat bag positioned in the proximal stomach of six healthy subjects. RESULTS: In the volume range 100-700 ml, our three dimensional system showed excellent correlation (r=0.99) between estimated and true volumes (limits of agreement -3.4 to 11.0 ml) and a low interobserver variation (limits of agreement -10.9 to 6.7 ml). After ingestion of a 500 ml meat soup meal, patients with reflux oesophagitis revealed a larger volume of the total and proximal stomach at two and 10 minutes (p=0.05; p=0.01, respectively), and an increased proximal/distal intragastric volume ratio at 10 minutes (p=0.04). Patients also experienced more epigastric fullness than controls (p=0.0006). CONCLUSIONS: The present three dimensional ultrasound system showed excellent agreement with true volumes and low interobserver variation. Soon after a liquid meal, patients with reflux oesophagitis have abnormal pooling of the ingested liquid in the proximal stomach.

Controversies in dyspepsia.

Even in the absence of visible lesions like an ulcer, cancer or oesophagitis, patients with functional dyspepsia may complain of severe dyspeptic symptoms and have a poor quality of life. Characteristically, these patients also often have a low estimate of their own health and have complaints from several organ systems. The cause of the disease is not known. Both central nervous system and gastric disturbances appear to be involved, and their relative importance is controversial. There is no clear beneficial effect of acid suppression or H. pylori eradication although effects of such therapy may be seen in minor subgroups. New findings emphasise the importance of distinguishing between functional dyspepsia and gastro-oesophageal reflux disease, which exhibit completely different gastric accommodation patterns to a meal and have very different therapeutic potential. The effect of drugs like glyceryl trinitrate, glucagon, sumatriptan and buspirone which all concomitantly improve symptoms and gastric accommodation support the important role of abnormal gastric accommodation to meals in patients with functional dyspepsia. A hypothetical model for the pathogenesis of functional dyspepsia is presented. It incorporates four established abnormalities: various psychological abnormalities, low vagal tone, impaired gastric relaxation, and visceral hypersensitivity, in a logical interplay along the brain-gut axis.

Stability of gastric secretory inhibition during 6-month treatment with omeprazole in patients with gastroesophageal reflux disease.

OBJECTIVE: A trend toward relapse of reflux symptoms and esophagitis during long-term treatment with proton pump inhibitors has been reported. The purpose of this study was to evaluate the existence of tachyphylaxia to the effect of proton pump inhibitors on gastric acidity and gastroesophageal reflux over time. METHODS: A total of 23 patients with reflux esophagitis underwent 24-h intragastric and intraesophageal pH-metry after 7, 90, and 180 days of continued dosing with 20 mg of omeprazole once daily before breakfast. RESULTS: The total median percentages of time gastric pH <4 (interquartile range) were 49% (35-70%), 60% (36-76%), and 42% (26-66%) after 7, 90, and 180 days (p = 0.14). Percentages of time gastric pH <3 were 41%, 54%, and 34%, respectively (p = 0.19). The median percentages of total time esophageal pH <4 were 1.1%, 2.5%, and 1.1%, respectively (p = 0.70). Healing of esophagitis was achieved in 84% of the patients after 6 months. Heartburn improved in six, worsened in three, and was unchanged in 10 patients (p = 0.16). There was no statistical significant relationship between change in esophageal acid exposure and change in severity of heartburn. CONCLUSIONS: A dose of 20 mg of omeprazole once daily consistently controlled patients' symptoms and kept gastric acidity at a stable level over a period of 6 months. There is no evidence of diminution in the effects of 20 mg of omeprazole over time that could indicate the development of tolerance.

Gastric accommodation studied by ultrasonography in patients with reflux esophagitis.

The aim of this study was to investigate gastric accommodation to a meal in patients with reflux esophagitis using ultrasonography. Twenty consecutive patients with reflux esophagitis of grade I (14) or II (6) and 20 healthy subjects underwent ultrasonographic measurements of the stomach before and after ingestion of a 500 ml soup meal. Reflux esophagitis patients revealed a significantly larger sagittal area of the proximal stomach at 5 min (P = 0.002) and 15 min (P = 0.007) postprandially and experienced more epigastric fullness after the meal (P = 0.0006). Postprandial fullness and sagittal area of the proximal stomach correlated significantly (r = 0.69; P = 0.0007). We conclude that patients with mild or moderate reflux esophagitis have a larger sagittal area of the proximal stomach and more postprandial fullness in response to a soup meal than healthy subjects. Postprandial distension of the proximal stomach may be a pathogenetic factor in reflux esophagitis.

Detection of guaiacol produced by Alicyclobacillus acidoterrestris in apple juice by sensory and chromatographic analyses, and comparison with spore and vegetative cell populations.

Spoilage of fruit juice by Alicyclobacillus acidoterrestris is characterized by a distinct medicinal or antiseptic off odor attributed to guaiacol, a metabolic by product of the bacterium. Detection of low populations of A. acidoterrestris that would precede sensory detection of guaiacol would enable juice processors to select appropriate processing and storage conditions that would minimize or eliminate spoilage. The objective of this study was to determine the recognition threshold of guaiacol in apple juice by sensory analysis and the population of A. acidoterrestris and incubation time at 21 and 37 degrees C necessary for chemical detection of guaiacol. Commercially sterilized apple juice (pH 3.54 +/- 0.04, 11.3 +/- 0.3 degrees Brix) was inoculated with a five-strain mixture of A. acidoterrestris spores (2.98 log10 CFU/ml) and stored at 21 or 37 degrees C for up to 61 days. Using an experienced sensory panel and the forced-choice ascending concentration method of limits, the best estimate threshold (BET) for recognition of guaiacol added to uninoculated apple juice was 2.23 ppb. Numbers of A. acidoterrestris spores and cells in inoculated juice remained constant during the 61-day storage period; however, the panel detected (P < or = 0.01) guaiacol in juice stored at 37 degrees C within 8 days. At three of four sampling times ranging from 13 to 61 days at which the sensory panel detected (P < or = 0.001) guaiacol, concentrations of 8.1 to 11.4 ppb were detected by chromatographic analysis. The panel detected (P < or = 0.1 to P < or = 0.01) guaiacol in five samples stored at 21 to 37 degrees C for 8 to 61 days in which the compound was not detected by chromatographic analyses. It appears that guaiacol content in apple juice inoculated with A. acidoterrestris is not always correlated with numbers of cells, and the limit of sensitivity of chromatographic quantitation of the compound is higher than the BET.

The effect of Helicobacter pylori eradication on gastro-oesophageal reflux.

BACKGROUND: Increased prevalence of oesophagitis has been reported following eradication of Helicobacter pylori. We hypothesized that H. pylori eradication might increase gastro-oesophageal acid reflux in patients with reflux oesophagitis. METHODS: Twenty-five consecutive patients (13 male, 12 female) with H. pylori infection and reflux oesophagitis grade I (22 patients) or II (three patients) were enrolled; mean age 49.9 (range 33-75) years. Twenty-four hour intra-oesophageal pH recording was performed before and 12 weeks after eradication of H. pylori, which was achieved using bismuth subnitrate suspension 150 mg q.d.s., oxytetracycline 500 mg q.d.s. and metronidazole 400 mg t.d.s. for 10 days. Eradication was confirmed by 14C-urea breath test 12 weeks after completion of treatment. The patients did not receive acid-suppressive medication. RESULTS: All patients had abnormal gastro-oesophageal reflux before anti-H. pylori treatment. After treatment, there was no significant change in the percentage of total time oesophageal pH < 4 (P=0.46) in the 23 patients in whom the infection had been cured. Nine of the cured patients had increased acid exposure, whereas 14 had decreased acid exposure. No significant change in reflux symptom scores was found. There was no relationship between change in acid exposure and symptom improvement. CONCLUSIONS: Twelve weeks after H. pylori eradication there was no consistent change in gastro-oesophageal acid reflux in patients with mild or moderate reflux oesophagitis.

Spiramycin is comparable to oxytetracycline in eradicating H. pylori when given with ranitidine bismuth citrate and metronidazole.

BACKGROUND: We have consistently achieved about 90% eradication of H. pylori with liquid bismuth, metronidazole and oxytetracycline. AIM: To test eradication and adverse events of ranitidine bismuth citrate (RBC) when given with metronidazole and either oxytetracycline or spiramycin. METHODS: One hundred and eighty-three patients were randomized to one of four 10-day regimens: RBC400OM: RBC 400 mg b.d., oxytetracycline 500 mg q.d.s.; RBC400SM: RBC 400 mg b.d., spiramycin 1 g q.d.s.; RBC200OM: RBC 200 mg q.d.s., oxytetracycline 500 mg q.d.s.; RBC200SM: RBC 200 mg q.d.s., spiramycin 1 g q.d.s. Additionally, all patients received metronidazole 400 mg q.d.s. A 14C-urea breath test was performed at 8 weeks. RESULTS: Intention-to-treat eradication rates were 94%, 91%, 94% and 89% with RBC400OM, RBC400SM, RBC200OM and RBC200SM, respectively (P = 0.81). Eradication was significantly higher in ulcer patients (97%) than in those with diagnoses other than ulcer (86%) (P = 0.009). There was a strong tendency to better eradication among those who had never smoked (100%) compared with ex-smokers (93%) and smokers (89%) (P = 0.06). Fifty-three per cent experienced at least one moderate or severe adverse event, and women had more adverse events than men (P = 0.0002). CONCLUSIONS: All four regimens had comparable efficacy and adverse events. Eradication was significantly better in ulcer patients but there was a trend to better eradication in those who smoked less, used less alcohol and exercised more. Adverse events were frequent, perhaps because of the large dose of metronidazole used, but few patients stopped treatment.

Bismuth-based combination therapy for Helicobacter pylori-associated peptic ulcer disease (metronidazole for eradication, ranitidine for pain).

OBJECTIVES: 180 Helicobacter pylori-positive patients with peptic ulcer disease were randomly allocated to double-blind placebo-controlled treatment with one of four anti-H. pylori regimens consisting of bismuth subnitrate suspension (B), oxytetracycline (OT), metronidazole (M)/metronidazole placebo, or ranitidine (R)/ranitidine placebo. METHODS: Regimen 1: B 150 mg q.i.d., OT 500 mg q.i.d., M 400 mg t.i.d. for 10 days and R 300 mg b.i.d. for 4 wk. Regimen 2: same as regimen 1 except ranitidine. Regimen 3: same as regimen 1 except metronidazole. Regimen 4: same as regimen 1 except metronidazole and ranitidine. Gastroscopy and 14C-urea breath test were performed 4 wk after cessation of therapy, and breath test six months after cessation. RESULTS: According to intention-to-treat analysis, H. pylori eradication rates were 96%, 91%, 20%, and 9% with regimens 1, 2, 3, and 4, respectively. Comparing regimens 1+2 and 3+4, the eradication rates with and without metronidazole were 93% and 14%, respectively (p < 0.0001). Metronidazole increased the occurrence of diarrhea and abdominal pain. Comparing regimens 1+3 with 2+4 ranitidine did not influence H. pylori eradication (58% with and 50% without ranitidine; p = 0.37) or ulcer healing (93% with and 90% without ranitidine; p = 0.72) significantly, but reduced the occurrence of pain (p < 0.01). Six months after treatment, three patients who were H. pylori negative at 4 wk had become positive. These three had all received metronidazole placebo. H. pylori status remained negative in the other 85 patients. CONCLUSIONS: H. pylori eradication with this triple therapy is critically dependent on metronidazole. Adding ranitidine reduces the occurrence of abdominal pain during such therapy.

Bismuth therapy for Helicobacter pylori infection. A review of five years experience at a university hospital in Norway.

BACKGROUND: Eradication of H. pylori cures peptic ulcer disease. Bismuth and antibiotics in various combinations were tested at a single university hospital. METHODS: The standard treatment was bismuth subnitrate, metronidazole and oxytetracycline. A positive biopsy urease test was the main inclusion criterium, whereas a negative 14C-urea breath test performed at least four weeks after cessation of therapy was the main indicator of cured infection, and performed later for reinfection. In separate studies we tested the absorption of bismuth subnitrate compared to other bismuth preparations, what aspects of bismuth-based triple therapy are most important to obtain maximum eradication, what can be done to decrease side effects, and the reliability of diagnostic methods. RESULTS: The absorption of bismuth from bismuth subnitrate was very low. More than 90% cure rates were usually obtained. Including metronidazole in the regimen increased side effects but was crucial for effectiveness. Spiramycine could replaced oxytetracycline without substantial loss of effectiveness. Effectiveness was decreased if the patients had recently used metronidazole. Aluminium containing antacids and chlorhexidine were not very useful. Side effects were frequent, up to 60%, but usually mild and very few patients withdrew from treatment. Adding ranitidine to the regimen reduced abdominal pain. 14C-urea breath test was the "gold standard" and the specificity of the biopsy urease test in diagnosing H. pylori infection was high. CONCLUSIONS: Bismuth combination therapy combines high effectiveness with acceptable side effects and low cost. Biopsy urease test and urea breath test are reliable indicators of H. pylori infection.