Artificial sweetener saccharin disrupts intestinal epithelial cells' barrier function in vitro.

SCOPE: Consumption of non-nutritive sweeteners (NNS) is a dietary practice used by those who wish to lose weight or by patients on a sugar-restricted diet such as those with DM2. Although these substances are safe, possible biological interactions with the digestive tract, particularly in relation to intestinal permeability, have not been studied. Thus, the current work sought to investigate the action of different NNS on intestinal permeability using an in vitro Caco-2 cell model. METHODS AND RESULTS: Caco-2 cells were incubated with acesulfame K, aspartame, saccharin, or sucralose at equimolar concentrations. Acesulfame K, aspartame, and sucralose did not disrupt monolayer integrity in the cells. However, saccharin increased paracellular permeability and decreased transepithelial electrical resistance (TEER) via a non-cytotoxic mechanism. The levels of the tight junction protein claudin-1 were reduced in Caco-2 cells that had previously been exposed to saccharin. The inhibition of nuclear factor-κB (NF-κB) was able to prevent the reduction in TEER induced by saccharin treatment. Thalidomide, as an inhibitor of ubiquitin ligase, was able to prevent the decrease in claudin-1 protein expression and the TEER reduction in Caco-2 cells. CONCLUSIONS: Saccharin disrupts monolayer integrity and alters paracellular permeability in a Caco-2 cell monolayer model, via a mechanism involving NF-κB activation, resulting in the ubiquitination of the tight junction protein claudin-1. Saccharin consumption may potentially alter the intestinal integrity in humans.

Relationship of IL-1 and TNF-α polymorphisms with Helicobacter pylori in gastric diseases in a Brazilian population.

It is well known that the risk of development of gastric cancer (GC) in Helicobacter pylori-infected patients depends on several factors. Thus, the aim of this study was to investigate the effect of proinflammatory cytokine gene polymorphisms for IL-1ß, IL-1RN and TNF-α on the development of GC in a Brazilian population. A total of 202 biopsies obtained from Brazilian patients with chronic gastritis and GC were included in the study. Infection with H. pylori cagA+ was determined by the polymerase chain reaction (PCR) as previously described. IL-1ß, IL-1RN and TNF-α polymorphism genotyping was performed by restriction fragment length polymorphism PCR. Associations between gene polymorphisms, clinical diseases and virulence markers were evaluated using either the χ² test or the Fisher exact test. Our results demonstrated that the IL-1ß -511 C/C and IL-1ß -511 C/T alleles were associated with chronic gastritis in H. pylori-positive patients (P = 0.04 and P = 0.05, respectively) and the IL-1ß -511 C/C genotype was associated with GC (P = 0.03). The frequency of IL-1RN alleles from patients with chronic gastritis and GC indicated that there was no difference between the genotypes of the groups studied. Similar results were found for TNF-α -308 gene polymorphisms. Our results indicate that the IL-1ß -511 C/C and C/T gene polymorphisms are associated with chronic gastritis and GC development in H. pylori-infected individuals.

Two-dimensional chromatography method applied to the enantiomeric determination of lansoprazole in human plasma by direct sample injection.

A two-dimensional HPLC method based on the direct injection of biological samples has been developed and validated for the determination of lansoprazole enantiomers in human plasma. The lansoprazole enantiomers were extracted from the biological matrix using an octyl restricted access media bovine serum albumin column (C8 RAM BSA) and the enantioseparation was performed on an amylose tris(3,5-dimethoxyphenylcarbamate) chiral column using acetonitrile:water (35:65 v/v) and UV detection at 285 nm. Analysis time was 25 min with no time spent on sample preparation. The method was applied to the analysis of the plasma samples obtained from nine Brazilian volunteers who received a 30 mg oral dose of racemic lansoprazole and was able to quantify the enantiomers of lansoprazole in the clinical samples analyzed.

A simple high-performance liquid chromatographic method for the determination of diclofenac in human plasma: application to a comparative bioavailability study.

A rapid, sensitive and specific method to quantify diclofenac in human plasma using indomethacin as the internal standard (IS) is described. Samples were extracted using protein precipitation protocol and analyzed by high performance liquid chromatography coupled to ultraviolet detection at 276 nm. Chromatography was performed isocratically with a run time of 8.0 min and the retention time observed for diclofenac and IS was 6.0 and 7.0 min, respectively. The calibration curve was linear over the range 50 - 4,000 ng/ml (r2 > 0.9995). The mean recovery of diclofenac ranged from 88.76 to 99.14% and the limit of quantification was 50 ng/ml. Intrabatch precision and accuracy (%CV) of the method ranged from 0.86 to 7.60%, and 99.34 to 103.8%, respectively. Interbatch precision (%CV) and accuracy ranged from 0.26 to 11.4%, and 92.00 to 105.34%, respectively. This HPLC method was used to determine the relative pharmacokinetics of two diclofenac-cholestyramine 140 mg capsule formulations. The study was conducted using an open, randomized and crossover design with a 1-week washout interval. A single 140 mg dose (equivalent to 70 mg of diclofenac) of each formulation was administered to 26 healthy volunteers (13 males and 13 females) and blood samples were obtained over 12-h interval. The geometric mean of diclofenac-cholestyramine/Flotac ratio was 90.53% for AUC0-12 and 100.22% for Cmax. Since the 90% CI for Cmax and AUCs ratios were all inside the 80 - 125% interval, it was concluded that the diclofenac-cholestyramine test formulation is bioequivalent to Flotac regarding both the rate and the extent of absorption.

Influence of Helicobacter pylori infection on the expression of MLH1 and MGMT in patients with chronic gastritis and gastric cancer.

The aim of the present study was to evaluate the influence of Helicobacter pylori on MLH1 and MGMT mRNA levels in patients with chronic gastritis and gastric cancer. The study included 217 patients, of which 26 were uninfected, 127 had chronic gastritis and were H. pylori-positive, and 64 had gastric cancer. Bacterial genotypes were evaluated by polymerase chain reaction (PCR), and the expression levels of MLH1 and MGMT were determined by quantitative real-time PCR and immunohistochemistry. There was an association between infection with cagA, vacA s1m1 strains and gastric cancer development. When the gastric epithelium and associated inflammation were examined for expression of MLH1 and MGMT, an overall increase in expression was observed. On the other hand, these levels decrease significantly among gastric cancer patients. The loss of MLH1 and MGMT expression in gastric cancer patients suggests that it is not an early event in H. pylori-associated gastric carcinogenesis.

Bioequivalência de duas formulações de oxalato de escitalopram comprimidos em voluntários sadios administradas em jejum / Bioequivalence of two tablets formulations of escitalopram oxalate in healthy volunteers under fasting conditions

O estudo foi conduzido para verificar a bioequivalência entre duas formulações de oxalato de escitalopram 10 mg, comprimidos. Foram 32 voluntários sadios de ambos os sexos que participaram no estudo randomizado, cruzado, dois períodos, com washout mínimo de dez dias. Um comprimido de cada formulação foi administrado após jejum noturno de dez horas. Após administração, amostras seriadas de sangue foram coletadas por 144 horas. As amostras de plasma foram analisadas para determinação do escitalopram por método validado de cromatografia líquida acoplada à detecção por espectrometria de massas (LC-MS-MS). Os parâmetros farmacocinéticos área sob a curva de concentração plasmática do tempo zero a última concentração medida (ASC0-t) e concentração máxima observada (Cmax) foram os principais critérios para verificação da bioequivalência entre as formulações. Área sob a curva de zero a infinito (ASC0-inf), tempo em que ocorre Cmax (Tmax) e meia-vida (t1/2) também foram determinados. Os intervalos de confiança (IC) de 90% obtidos por análise de variância (ANOVA) não mostraram diferenças significativas entre as duas formulações e caíram dentro dos limites pre-estabelecidos (96,91-106,79 para ASC0-t e 89,40-102,39 para Cmax). A bioequivalência entre as duas formulações foi demonstrada tanto em termos de taxa quanto de extensão da absorção.

Determination of dimenhydrinate in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a relative bioavailability study.

Here we present a sensitive and specific liquid chromatography-tandem mass spectrometric method for the quantification of dimenhydrinate (I) in human plasma. Sample preparation is conducted using citalopram (II) addition as an internal standard (IS), liquid-liquid extraction with basified plasma using a mixture hexane/acetate (1:1, v/v) as the extracting solvent, and the final extract reconstituted in the mobile phase. I and II (IS) were injected in a C8 column with the mobile phase composed of methanol:isopropanol:water:formic acid (78.00:19.92:2.00:0.08, v/v/v/v) and monitored using a positive electrospray source with tandem mass spectrometry analyses. The selected reaction monitoring (SRM) was set using precursor ion and product ion combinations of m/z 256.0>167.0 and m/z 325.0>109.0 for I and II, respectively. The limit of quantification (LOQ) was 0.4 ng/mL, the dynamic range being 0.4-200 ng/mL. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of plasma samples taken up to 24 h after oral administration of 100 mg of dimenhydrinate in healthy volunteers demonstrated its applicability to bioavailability studies.

Analysis of DNA damage induced by aflatoxin B1 in Dunkin-Hartley guinea pigs.

Aflatoxin B1 (AFB1) is among the most potent naturally occurring carcinogens and classified as a group I carcinogen. Since the ingestion of aflatoxin-contaminated food is associated with several liver diseases, the aim of the present study was to evaluate the effect of 2, 20, and 200 ppb of AFB1 on DNA damage in peripheral blood lymphocytes and liver cells in Dunkin-Hartley guinea pigs. The animals were divided into four groups according to the given diet. After the treatment the lymphocytes and liver cells were isolated and DNA damage determined by Comet assay. The levels of DNA damage in lymphocytes were higher animals treated with 200 ppb of AFB1-enriched diet (P = 0.02). In the liver cells there were a relationship between the levels of DNA damage and the consumption of AFB1 in all studied groups. These results suggest that Comet assay performed on lymphocytes is a valuable genotoxic marker for high levels of exposure to AFB1 in guinea pig. Additionally our results indicate that the exposure to this toxin increases significantly and increases the level of DNA damage in liver cells, which is a key step on liver cancer development. We also suggest that the Comet assay is an useful tool for monitoring the genotoxicity of AFB1 in liver.

The inhibitory effects of H+ K+ ATPase inhibitors on human neutrophils in vitro: restoration by a K+ ionophore.

OBJECTIVE: This study investigated the ability of proton pump inhibitors (PPI), such as omeprazole and pantoprazole, to inhibit neutrophil migration, calcium mobilization and the mechanisms involved in this inhibition. METHODS: Neutrophils were incubated with different concentrations of omeprazole and pantoprazole for 30 min and stimulated to migrate with fMLP and IL-8. Treatment toxicity was assessed by MTT assay. The intracellular calcium levels were analyzed in neutrophils pre-treated with omeprazole and pre-loaded with FURA-2AM, when stimulated with fMLP. The activity of p38 MAP Kinase was evaluated by Western blot after treatment with omeprazole. RESULTS: Omeprazole is able to inhibit neutrophil chemotaxis to fMLP and IL-8. Pantoprazole demonstrated the same ability. This inhibitory effect was not due to a toxic effect of the proton pump inhibitors. Inhibition of v-ATPase by bafilomycin did not modify the ability of fMLP or IL-8 to induce neutrophil migration. Omeprazole was also able to decrease intracellular calcium availability. The addition of a potassium ionophore, nigericin, restored the migratory ability, as well as the intracellular calcium levels. The activity of p38 MAP Kinase was decreased in neutrophils pretreated with omeprazole. CONCLUSION: Proton pump inhibitors promote inhibition of H+ K+ ATPase in neutrophils, resulting in cationic flow disturbances through the cellular membrane that, consequently, inhibit migratory and intracellular events such as calcium influx and p38 MAP Kinase activation.

Effect of Helicobacter pylori infection and acid blockade by lansoprazole on clarithromycin bioavailability.

The effect of proton pump inhibitors and Helicobacter pylori infection on the bioavailability of antibiotics is poorly understood. We determined the effects of 5-day oral administration of 60 mg lansoprazole on the bioavailability of clarithromycin in individuals with and without H. pylori infection. Thirteen H. pylori-infected and 10 non-infected healthy volunteers were enrolled in a study with an open-randomized two-period crossover design and a 21-day washout period between phases. Plasma concentrations of clarithromycin in subjects with and without lansoprazole pre-treatment were measured by liquid chromatography coupled to a tandem mass spectrometer. Clarithromycin Cmax and AUC0-10 h were significantly reduced after lansoprazole administration. In addition, lansoprazole treatment of the H. pylori-positive group resulted in a statistically significant greater reduction in Cmax (40 vs 15%) and AUC0-10 h (30 vs 10%) compared to lansoprazole-treated H. pylori-negative subjects. Thus, treatment with lansoprazole for 5 days reduced bioavailability of clarithromycin, irrespective of H. pylori status. This reduction, however, was even more pronounced in H. pylori-infected individuals.

Determination of memantine in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study.

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of memantine (I) in human plasma is presented. Sample preparation consisted of the addition of amantadine (II) as internal standard (IS), liquid-liquid extraction in basic conditions using a mixture of diethyl ether-chloroform (7:3, v/v) as extracting solvent, followed by centrifugation, solvent evaporation and sample reconstitution in methanol. Both I and II (internal standard) were analyzed using a C18 column and a mobile phase composed of methanol-water-formic acid (80:20:0.1, v/v/v). Eluted compounds were monitored using positive mode electrospray (ES) tandem mass spectrometry. The analyses were carried out by selected reaction monitoring (SRM) using the parent to daughter combinations of m/z 180>163 (memantine) and m/z 152>135 (amantadine). The peak areas from the analyte and IS were used for quantification of I. The achieved limit of quantification (LOQ) was 0.1 ng/mL; the assay exhibited a linear dynamic range of 0.1-50.0 ng/mL with a determination coefficient (r2) of at least 0.98. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of samples taken up to 320 h after oral administration of 20mg (two 10mg capsules) of I in healthy volunteers demonstrated the applicability to bioequivalence studies.

Validation of a selective method for determination of paroxetine in human plasma by LC-MS/MS.

PURPOSE: A sensitive, robust, and selective liquid chromatographic-tandem mass spectrometric method (LC-MS/MS) was developed and validated for paroxetine quantification in human EDTA plasma. METHODS: Sample preparation was based on liquid-liquid extraction using a mixture of ethyl acetate/hexane (50/50; v/v) to extract the drug and internal standard from plasma. Chromatography was performed on a C-18 analytical column and the retention times were 1.6 and 1.7 for paroxetine and fluoxetine (IS), respectively. The ionization was optimized using ESI(+) and selectivity was achieved by tandem mass spectrometric analysis using MRM functions, 330.0 --> 70.0 and 310 --> 43.9 for paroxetine and fluoxetine. RESULTS: Analytical curve ranged from 0.2 to 20.0 ng/mL. Inter-day precision and accuracy of the quality control (QC) samples were < 15% relative standard deviation (RSD). Analyte stability during sampling processing and storage were established. CONCLUSION: Validation results on linearity, specificity, accuracy, precision as well as application to the analysis of samples taken up to 120 h after oral administration of 20 mg of paroxetine in 28 healthy volunteers were found to be of good performance in bioequivalence study.

Validated method for determination of bromopride in human plasma by liquid chromatography--electrospray tandem mass spectrometry: application to the bioequivalence study.

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method for the quantification of bromopride I in human plasma is presented. Sample preparation consisted of the addition of procainamide II as the internal standard, liquid-liquid extraction in alkaline conditions using hexane-ethyl acetate (1 : 1, v/v) as the extracting solvent, followed by centrifugation, evaporation of the solvent and sample reconstitution in acetonitrile. Both I and II (internal standard, IS) were analyzed using a C18 column and the mobile-phase acetonitrile-water (formic acid 0.1%). The eluted compounds were monitored using electrospray tandem mass spectrometry. The analyses were carried out by multiple reaction monitoring (MRM) using the parent-to-daughter combinations of m/z 344.20 > 271.00 and m/z 236.30 > 163.10. The areas of peaks from analyte and IS were used for quantification of I. The achieved limit of quantification was 1.0 ng/ml and the assay exhibited a linear dynamic range of 1-100.0 ng/ml and gave a correlation coefficient (r) of 0.995 or better. Validation results on linearity, specificity, accuracy, precision and stability, as well as application to the analysis of samples taken up to 24 h after oral administration of 10 mg of I in healthy volunteers demonstrated the applicability to bioequivalence studies.

Development and validation of a selective and robust LC-MS/MS method for quantifying amlodipine in human plasma.

A liquid chromatographic-tandem mass spectrometric method (LC-MS/MS) for quantifying amlodipine in human plasma was developed and validated. Sample preparation was based on liquid-liquid extraction using NaOH and a mixture of ethyl acetate/hexane (80/20; v/v). Chromatography was performed on a C-18 analytical column and the retention times were 1.9 and 3.0 min for amlodipine and nimodipine (internal standard), respectively. The ionization was optimized using ESI(+) and enhanced selectivity was achieved using tandem mass spectrometric analysis via two MRM functions, 409 --> 238 and 418 --> 343 for amlodipine and nimodipine. The calibration curve ranged from 0.2 to 20.0 ng/mL. The inter-day precision and accuracy and the relative standard deviation (RSD) were <15%. The analyte was shown to be stable over the time-scale of the whole procedure. The robustness of the method was demonstrated by the good reproducibility of the results obtained during the analysis of clinical samples.

Plasma hydroxy-metronidazole/metronidazole ratio in hepatitis C virus-induced liver disease.

It has been suggested that the measurement of metronidazole clearance is a sensitive method for evaluating liver function. The aim of this study was to evaluate the usefulness of plasma hydroxy-metronidazole/metronidazole ratios as indicators of dynamic liver function to detect changes resulting from the various forms of chronic hepatitis C virus (HCV) infection. A total of 139 individuals were studied: 14 healthy volunteers, 22 healthy, asymptomatic, consecutive anti-HCV-positive HCV-RNA negative subjects, 81 patients with chronic hepatitis C (49 with moderate/severe chronic hepatitis and 34 with mild hepatitis), and 20 patients with cirrhosis of the liver. HCV status was determined by the polymerase chain reaction. Plasma concentrations of metronidazole and its hydroxy-metabolite were measured by reverse-phase high-performance liquid chromatography with ultraviolet detection in a blood sample collected 10 min after the end of a metronidazole infusion. Anti-HCV-positive HCV-RNA-negative individuals demonstrated a significantly reduced capacity to metabolize intravenously infused metronidazole compared to healthy individuals (0.0478 +/- 0.0044 vs 0.0742 +/- 0.0232). Liver cirrhosis patients also had a reduced plasma hydroxy-metronidazole/metronidazole ratio when compared to the other groups of anti-HCV-positive individuals (0.0300 +/- 0.0032 vs 0.0438 +/- 0.0027 (moderate/severe chronic hepatitis) vs 0.0455 +/- 0.0026 (mild chronic hepatitis) and vs 0.0478 +/- 0.0044 (anti-HCV-positive, HCV-RNA-negative individuals)). These results suggest an impairment of the metronidazole metabolizing system induced by HCV infection that lasts after viral clearance. In those patients with chronic hepatitis C, this impairment is paralleled by progression of the disease to liver cirrhosis.

Enantiomeric determination of the plasma levels of omeprazole by direct plasma injection using high-performance liquid chromatography with achiral-chiral column-switching.

A direct injection high-performance liquid chromatographic (HPLC) method, with column-switching, for the determination of omeprazole enantiomers in human plasma is described. A restricted access media (RAM) of bovine serum albumin (BSA) octyl column has been used in the first dimension for separation of the analyte from the biological matrix. The omeprazole enantiomers were eluted from the RAM column onto an amylose tris(3,5-dimethylphenylcarbamate) chiral column by the use of a column-switching valve and the enantioseparation was performed using acetonitrile-water (60:40 v/v) as eluent. The analytes were detected by their UV absorbance at 302 nm. The validated method was applied to the analysis of the plasma samples obtained from 10 Brazilian volunteers who received a 40 mg oral dose of racemic omeprazole and was able to quantify the enantiomers of omeprazole in the clinical samples analyzed. The assay was able to determine the cytochrome P450 2C19 phenotype of the subjects participating in this study.

Amoxicillin and ampicillin are not transferred to gastric juice irrespective of Helicobacter pylori status or acid blockade by omeprazole.

BACKGROUND: The effects of proton pump inhibitors and Helicobacter pylori infection on the distribution of drugs used for the eradication of the bacteria are poorly understood. AIM: The aim of this study was to investigate the effects of a 7-day administration of 20 mg of omeprazole on the pharmacokinetics of amoxicillin and ampicillin in the plasma, saliva and gastric juice of individuals with and without H. pylori infection. METHODS: Fifty-four healthy volunteers without endoscopic lesions were enrolled. Twenty-six volunteers were included in the amoxicillin study and 28 individuals in the ampicillin study. Each study had an open randomized two-period crossover design and a 21-day washout period between phases. Plasma, saliva and gastric juice concentrations of amoxicillin and ampicillin in subjects with and without omeprazole pre-treatment were measured by reversed-phase HPLC using UV detection. RESULTS: Neither pre-treatment with omeprazole nor H. pylori infection interfered with the plasma bioavailability of amoxicillin or ampicillin, as assessed by the AUC0-2 h. Neither ampicillin nor amoxicillin were detected in saliva or gastric juice in any study phase. CONCLUSION: Short-term treatment with omeprazole does not interfere with the pharmacokinetics of amoxicillin or ampicillin. Our results also exclude the presence of a transfer mechanism for amoxicillin or ampicillin from the plasma to the gastric lumen.

Neutrophil migration during liver cirrhosis in rabbits.

1. The aim of the present study was to investigate neutrophil chemotaxis during the induction of liver cirrhosis in rabbits. 2. Liver cirrhosis was induced in male New Zealand white rabbits. The study consisted of three experimental groups: (i) group A (n=16) served as the control and received only normal chow and all rabbits in this group were killed at 16 weeks; (ii) group B rabbits (n=8) were killed immediately after the chemotaxis assay, which was performed 24 h after CCl4 administration, at weeks 2, 4, 6 and 8; and (iii) in group C rabbits (n=19), the chemotaxis assay was performed every second week on the day before CCl4 administration for 16 weeks and all animals in this group were killed at 16 weeks. 3. Four of six rabbits in group B had liver cirrhosis at week 8. In group C, liver cirrhosis occurred in seven of eight animals. All rabbits with liver cirrhosis had an inflammatory infiltrate of neutrophils. In group B, there was a significant increase in polymorphonuclear cells and neutrophil chemotaxis and a significant reduction in mononuclear leucocytes at week 8. The rabbits in group C showed a significant increase in total leucocyte and polymorphonuclear numbers at week 10. A significant increase in neutrophil chemotaxis was also observed from week 2 through to week 6. 4. The presence of neutrophils in the liver of all rabbits with cirrhosis, associated with an increase in polymorphonuclear cell chemotaxis during this process, supports the view that this cell type has an important role in the development of toxic liver damage.

Increased primary resistance to recommended antibiotics negatively affects Helicobacter pylori eradication.

OBJECTIVE: To evaluate the efficacy of two commonly employed treatments for Helicobacter pylori infection and the impact of bacterial resistance to antibiotics on eradication rate. METHODS: Ninety-two consecutive H. pylori-positive patients with active peptic ulcer disease were randomly enrolled to receive a 7-day treatment with either lansoprazole 30 mg plus amoxicillin 1 g and clarithromycin 500 mg [all twice a day (b.i.d.), Group A, n = 46]; or bismuth subcitrate 125 mg four times a day (q.i.d.) plus tetracycline 500 mg q.i.d and furazolidone 200 mg b.i.d. (Group B, n = 46) H. pylori status was reassessed 30 days after completion of the therapy and bacterial resistance to the antibiotics was investigated using an in vitro assay. RESULTS: Five patients from each study group were lost to follow up. Both treatments resulted in similar H. pylori eradication rate: 66-60% (per protocol), 59-52% (intention-to-treat) in Groups A and B, respectively (non significant). However, eradication improved to 79% in the absence of H. pylori resistance to clarithromycin or amoxicillin. CONCLUSION: Primary resistance to clarithromycin or amoxicillin may underscore a potentially serious problem for the eradication of H. pylori infection. Testing for bacterial resistance may become necessary to improve therapeutic efficacy.

Prevalence of peptic lesions in asymptomatic, healthy volunteers.

AIM: To investigate the presence of lesions of the upper gastrointestinal tract of asymptomatic, healthy volunteers undergoing clinical pharmacology studies. MATERIAL AND METHODS: A series of 53 volunteers (45 male, 23 Helicobacter pylori negative and 30 Helicobacter pylori positive) underwent upper gastrointestinal endoscopy. Helicobacter pylori status was assessed using two methods (rapid urease test and histology) from antral and corpus biopsies. RESULTS: Peptic lesions were found in 24 (45%) subjects: erosive oesophagitis, gastric/duodenal ulcers and gastric/duodenal erosions were found in 23%, 9% and 36% of these volunteers, respectively. Helicobacter pylori-positive subjects had significantly (p<0.05) more gastroduodenal lesions than Helicobacter pylori negative individuals (12/30 vs 3/23). The presence of peptic ulcers and erosive oesophagitis was similar in Helicobacter pylori-positive and -negative individuals. CONCLUSIONS: The possibility that peptic lesions might exist in otherwise asymptomatic, healthy individuals cannot be ruled out. Helicobacter py lori-positive individuals have a significantly higher incidence of gastric and duodenal lesions than Helicobacter pylori negative subjects.