Influence of Helicobacter pylori infection and omeprazole treatment on gastric regional CO2

BACKGROUND: Gastric regional CO(2) accumulation indicates gastric mucosal hypoperfusion in critically ill patients. CO(2) is also a reaction product of urea degradation, and we therefore tested the hypothesis if regional pCO(2) is influenced by Helicobacter pylori infection. MATERIAL: Seven H. pylori-positive and 7 H. pylori-negative volunteers (age range 21-30 years) were investigated. During a 6- to 7-hour observation period, we obtained every 30 min arterial blood gases, gastric juice pH from a glass pH electrode and regional pCO2 from a gastric tonometer. The study protocol included subsequent periods of baseline measurements, pentagastrin stimulation (0.6 microg/kg/h/i.v.) and application of omeprazole (40 mg i.v.). RESULTS: Gastric regional pCO(2) was increased in H. pylori-positive versus H. pylori-negative subjects before (64.4 +/- 3.1 vs. 50.0 +/- 2.9 mm Hg, p < 0.005) but not after application of omeprazole. The effect of omeprazole on gastric juice pH was increased in H. pylori-positive subjects (mean pH during 4 h 6.1 +/- 0.3 in H. pylori-positive vs. 2.5 +/- 0.2 in H. pylori-negative subjects; p < 0.0001). There was a difference in arterial pCO(2) between H. pylori-positive and H. pylori- negative subjects (43.1 +/- 0.3 versus 38.9 +/- 0.3 mm Hg; p < 0.0001). CONCLUSION: H. pylori infection has a significant effect on gastric regional CO(2) that is suppressed by application of a proton pump inhibitor.     

Influence of H pylori on plasma ghrelin in patients without atrophic gastritis

AIM:To determine the association between H pylori infection and serum ghrelin levels in patients without atrophic gastritis.METHODS:Fifty consecutive patients(24 males and 26 females)with either H pylori-positive gastritis(n = 34)or H pylori-negative gastritis(n = 16)with normal gastric acid secretion determined by 24-h pHmetry and without atrophic gastritis in histopathology were enrolled in this study.Thirty-four H pylori-infected patients were treated with triple therapy consisting of a daily regimen of 30 mg lansoprazole bid,1 g amoxicillin bid and 500 mg clarithromycin bid for 14 d,followed by an additional 4 wk of 30 mg lansoprazol treatment.H pylori infection was eradicated in 23 of 34(67.6%)patients.H pylori-positive patients were given eradication therapy.Gastric acidity was determined via intragastric pH catethers.Serum ghrelin was measured by radioimmunoassay(RIA).RESULTS:There was no signifficant difference in plasma ghrelin levels between H pylori-positive and H pylori-negative groups(81.10 ± 162.66 ng/L vs 76.51 ± 122.94 ng/L).In addition,there was no significant difference in plasma ghrelin levels and gastric acidity levels measured before and 3 mo after the eradication therapy.CONCLUSION:H pylori infection does not influence ghrelin secretion in patients with chronic gastritis without atrophic gastritis.     

Direct measurement of gastric H^＋／K^＋-ATPase activities in patients with or without Helicobacterpylori-associated chronic gastritis

AIM: The role of Helicobacter pylori (H pylori) infection in gastric acid secretion of patients with chronic gastritis remains controversial. This study was designed to elucidate the effect of H pylori on H+/K+-ATPase activities in gastric biopsy specimens. METHODS: Eighty-two patients with chronic gastritis who had undergone upper endoscopy were included in this study. H pylori infection was confirmed by rapid urease test and histology. Gastric H+/K+-ATPase activities and serum gastrin concentrations were measured by an enzymatic method and radioimmunoassay, respectively. For those patients who received triple therapy for eradicating H pylori, changes in the activity of gastric H+/K+-ATPase and serum gastrin levels were also measured. RESULTS: The mean gastric H+/K+-ATPase activity in Hpylori-positive group (42 patients) was slightly higher than that in Hpylori-negative group (29 patients) (169.65±52.9 and 161.38±43.85nmol P/(mg·h),respectively, P=0.301). After eradication of H pylori, the gastric H+/K+-ATPase activities slightly decreased compared to prior therapy (165.03±59.50 and 158.42±38.93 nmol P/(mg·h), respectively, P=0.805). The mean basal gastrin concentration was slightly higher in H pylori-positive patients than in H pylori-negative patients (87.92±39.65 pg/mL vs75.04±42.57 pg/mL, P= 0.228). The gastrin levels fell significantly after the eradication of H pylori. (Before treatment 87.00±30.78 pg/mL, after treatment 64.73±18.96 pg/mL, P=0.015). CONCLUSION: Gastric H+/K+-ATPase activities are not associated with H pylori status in patients with chronic gastritis.     

Transfer of metronidazole to gastric juice: impact of Helicobacter pylori infection and omeprazole

BACKGROUND: The effects of Helicobacter pylori infection associated with inhibition of gastric acid secretion on the distribution of medications used for H. pylori eradication are poorly understood. The aim of this study was to investigate the effects of a 7-day administration of 20 mg omeprazole on the transfer of metronidazole from plasma to the gastric juice of individuals with and without H. pylori infection. METHODS: Fourteen H. pylori-positive and 14 H. pylori-negative male volunteers were enrolled in a study with an open, randomized, two-period crossover design with a 21-day washout period between phases. Plasma, salivary, and gastric juice concentrations of metronidazole in subjects with and without omeprazole treatment were measured with reversed-phase high-performance liquid chromatography/liquid chromatography. RESULTS: Metronidazole peak concentration (Cmax) was similar in plasma and saliva and was approximately threefold higher in gastric juice in all groups. Omeprazole treatment increased gastric pH and did not affect metronidazole Cmax or the time required for this to be reached (tmax) in plasma, saliva, or gastric juice. However, omeprazole significantly reduced metronidazole transfer from plasma to gastric juice in H. pylori-positive but not H. pylori-negative subjects, as shown by statistical analysis of AUC(0-2 h). CONCLUSION: Short-term treatment with omeprazole in H. pylori- positive volunteers reduces the amount of metronidazole transferred from plasma to gastric juice. This seems to occur in a pH-independent form.     

Omeprazole, Helicobacter pylori status, and alterations in the intragastric milieu facilitating bacterial N-nitrosation

BACKGROUND & AIMS: Omeprazole produces greater acid inhibition in Helicobacter pylori-positive than -negative subjects. We investigated whether this is accompanied by more profound changes in the intragastric milieu that facilitates bacterial synthesis of N-nitroso compounds. METHODS: Gastric juice pH; nitrite, ascorbic acid, and total vitamin C concentrations; and colonization by other bacteria were examined before and during omeprazole treatment in subjects with and without H. pylori infection. Studies were performed in the fasting state and after consumption of 2 mmol nitrate (equivalent to a salad meal). RESULTS: Before omeprazole, H. pylori-positive and -negative subjects were similar for all parameters. During omeprazole, H. pylori-positive subjects had a higher intragastric pH (7.8 vs. 3.0; P < 0.00001) and greater colonization with non-H. pylori species (5 x 10(7) vs. 5 x 10(5) CFU/mL; P < 0.05). These bacteria included nitrosating species. During omeprazole treatment, H. pylori-positive subjects had higher intragastric nitrite levels after the nitrate meal (median area under the concentration/time curve, 12,450 vs. 4708 micromol/L. min; P = 0.04). Omeprazole lowered intragastric vitamin C levels in H. pylori-positive but not -negative subjects (1.8 vs. 3.4 microg/mL, respectively; P = 0.02). CONCLUSIONS: In H. pylori-positive subjects, omeprazole produces disturbances in intragastric nitrite, vitamin C, and bacterial colonization that facilitate bacterial N-nitrosation. This may place them at increased risk of mutagenesis and carcinogenesis.     

Helicobacter pylori infection inhibits antral mucosal nitric oxide production in humans

BACKGROUND: Inducible NO synthase expression is upregulated in H. pylori-infected gastric mucosa, suggesting increased NO synthesis as part of a host defense reaction. This study investigates actual NO production in the human antrum in situ. METHODS: Gastroscopy with antral biopsy sampling and intragastric tonometric NO assessments were performed on H. pylori-positive and -negative volunteers. The antral mucosal specimens were analyzed with regard to inducible NO synthase (Western blotting) and the presence of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA) as well as L-arginine. RESULTS: Mucosal expression of inducible NO synthase was markedly increased in H. pylori infected subjects compared to noninfected ones. The ratio between the tissue contents of L-arginine and asymmetric dimethylarginine was considerably lower in the infected group. Antral output of NO was similar in the two groups during baseline conditions. Following intragastric L-arginine exposure. the antral NO production in controls was unaltered (from 442 ppb +/- 104 to 286 ppb +/- 94), whereas it increased (from 524 ppb +/- 162 to 1066 ppb +/- 274) in the infected individuals. CONCLUSIONS: The study confirms that NO synthase expression is increased in H. pylori-infected antral mucosa. However, NO synthesis is restricted owing to the presence of pathogen-induced competitive NO synthase inhibitors such as methylated arginines.     

Helicobacter pylori infection influences tumor growth of human gastric carcinomas

BACKGROUND: Helicobacter pylori infection is considered a risk factor for gastric carcinoma. However, the effect of eradication therapy in gastric carcinoma patients is not well known. The aim of this study was to investigate the relationship between H. pylori infection and tumor growth of gastric carcinoma. METHODS: Fifty-one patients with gastric carcinoma participated in the study. Thirty-three were H. pylori-positive, 6 were H. pylori-negative, and 12 were diagnosed with gastric carcinoma after eradication of H. pylori. To investigate tumor growth of gastric carcinoma, cell proliferation and angiogenesis of the tumors were evaluated by immunohistochemical techniques using Ki-67 and CD34. RESULTS: The Ki-67 labeling index was 47.9 +/- 2.6 (mean +/- s) in the H. pylori-positive group, 38.1 +/- 3.6 in the H. pylori-eradicated group, and 22.2 +/- 5.5 in the H. pylori-negative group. It was significantly lower in the H. pylori-eradicated and H. pylori-negative groups than in the H. pylori-positive one, and a significant difference was also found between the H. pylori-positive and H. pylori-eradicated groups. The microvessel counts were 62.5 +/- 3.0, 50.2 +/- 4.0, and 66.0 +/- 9.8 in the positive, eradicated, and negative groups, respectively. A significant difference was found between the H. pylori-positive and H. pylori-eradicated groups. CONCLUSION: Our results suggest that H. pylori infection is associated with cell proliferation, and its eradication may influence tumor vascularity of gastric carcinoma. Therefore, H. pylori eradication therapy may contribute to the suppression of tumor growth.     

Intragastric volatile N-nitrosamines, nitrite, pH, and Helicobacter pylori during long-term treatment with omeprazole

BACKGROUND & AIMS: This study evaluated the effect of long-term gastric acid suppressive therapy with omeprazole on intragastric levels of carcinogenic N-nitrosamines and related parameters. METHODS: Forty-five patients on long-term omeprazole medication (mean, 35 months) and 13 healthy subjects without medication participated. Volatile N-nitrosamines were determined in gastric juice and urine. Intragastric pH, nitrite, nitrate, and H. pylori status were determined. DNA isolated from gastric biopsy specimens was analyzed for precarcinogenic alkyl-DNA adducts. RESULTS: The intragastric pH in patients was significantly higher compared with controls (P = 0.0001). Gastric nitrite levels in patients were nonsignificantly higher. There was no difference in total levels of intragastric volatile N-nitrosamines between patients and controls, however, urinary N-nitrosodimethylamine excretion was higher in patients (P = 0.001). On omeprazole, Helicobacter pylori-positive vs. -negative patients had a nonsignificantly higher intragastric nitrite level and higher urinary N-nitrosodimethylamine excretion. No alkyl-DNA adducts could be detected in gastric epithelium. CONCLUSIONS: Increased intragastric pH caused by long-term treatment with omeprazole does not result in increased intragastric levels of nitrite and volatile N-nitrosamines. The significantly higher urinary N-nitrosamine excretion implies the risk of increased endogenous formation of N-nitrosamines during long-term omeprazole treatment. This risk may be higher in H. pylori-positive patients.     

Intragastric Nitric Oxide/Nitrite in Helicobacter pylori-Infected Subjects

Background: Nitrite (NO₂-) in swallowed saliva is reduced to nitric oxide (NO) and other nitrogen oxides by the intragastric acidity. This mechanism is probably important for the intragastric clearance of ingested micro-organisms and nitrosating compounds. The study examines the balance between intragastric NO and NO₂- in relation to endogenous acid production and infection with Helicobacter pylori. Methods: Six healthy H. pylori-negative and six H. pylori-positive volunteers with no known gastroduodenal pathology were examined after an overnight fast. Gastric NO was measured using a chemiluminescence technique and pH as well as NO₂- were analysed in gastric aspirates. Results: Gastric NO was slightly lower in H. pylori     

Apoptosis, proliferation and p53 gene expression of H. pylori associated gastric epithelial lesions

AIM:To study the relationship between Helicobacter pylori(H.pylori)and gaatric carcinoma and its possiblepathogenesis by H.pylori.METHODS:DNEL technique and immunohistochemicaltechnique were used to study the state of apoptosis,proliferation and p53 gone expression.A total of 100 gastricmucosal biopsy specimens,including 20 normal mucosa,30H.pylori-negative and 30 H.pylori-positive gastricprecancerous lesions along with 20 gastric carcinomas werestudied.RESULTS:There were several apoptotic cells in thesuperficial epithelium and a few proliferative cells within theneck of gestric glands,and no p53 protein expression innormal mucosa.In gestric carcinoma,there ware fewapoptotic cells,while there were a large number ofproliferative cells,and expression of p53 proteinsignificantly was increased.In the phase of metaplasia,theapoptotic index(Al,4.36%±1.95%),proliferative index(Pl,19.11%±6.79%)and positivity of p53 expression(46.7%)in H.pylori-positive group ware higher than thosein normal mucosa(P<0.01).Al in H.pylori-positive groupwas higher than that in H.pylori-negative group(3.81%±1.76%),Pl in H.pylori-positive group was higher than thatin H.pylori-negative group(12.23%±5.63%,P<0.01).Inthe phase of dysplasia,Al(2.31%±1.10%) in H.pylori-positive group was lower(3.05%±1.29%)than that in H.pylori-negative group,but Pl(33.89%±11.65%)wassignificantly higher(22.09±8018%,P<0.01).In phases ofmetaplasia,dysplasia and gastric cancer in the H.pylori-positive group,Als had an evidently greduall decreasingtrend(P<0.01),while Pls had an evidently gradualincreasing trend(P<0.05 or P<0.01),and there was alsoa trend of gradual increase in the expression of p53 gone.CONCLUSION:In the course of the formation of gastriccarcinoma,proliferation of gastric mucosa can be greatlyIncreased by H.pylori,and H.pylori can induce apoptosisin the phase of metaplasia,but in the phase of dysplesia H.pylorl can inhibit cellular apptosis.And H.pylori infectioncan strengthen the expression of mutated p53 gene.     

Gastric acid secretion of normal Japanese subjects in relation to Helicobacter pylori infection, aging, and gender

BACKGROUND: In Japan, where the incidence of gastric cancer is high, Helicobacter pylori infection could affect gastric acid secretion differently from that in Western countries. The aim of this study was to investigate the relationship between H. pylori infection, acid secretion, aging, and gender in normal Japanese subjects. METHODS: The study comprised 193 Japanese subjects who had undergone routine endoscopy. Gastrin-stimulated acid output was performed during the routine endoscopic examination using the endoscopic method of gastric acid secretory testing (EGT: endoscopic gastrin test), which has been reported previously. H. pylori status was determined by histology, rapid urease test, and serology. RESULTS: Mean EGT values were 3.9 +/- 1.5 mEq/10 min in H. pylori-negative men, 1.6 +/- 2.5 in H. pylori-positive men, 2.2 +/- 0.9 in H. pylori-negative women, and 1.5 +/- 1.2 in H. pylori-positive women. Although acid secretion was lower in H. pylori-positive subjects compared with H. pylori-negative subjects in both men and women, the decrease was more marked in men with H. pylori infection. Multiple linear regression analysis showed that aging is positively associated with gastric acid secretion in the H. pylori-negative subjects, whereas a negative association was found between them in the H. pylori-positive subjects. CONCLUSIONS: In Japanese subjects, aging affects gastric acid secretion differently depending on the status of H. pylori infection. H. pylori infection showed a stronger inhibitory effect on the acid secretion in men than in women. This gender-related difference in the susceptibility of acid secretion to H. pylori infection may explain the higher rates of gastric cancer in men in Japan.     

Effect of acid-suppressive therapy on Helicobacter pylori production of interleukin-8 in the gastric mucosa.

BACKGROUND: Recent studies have shown that acid-suppressive therapy increases the severity of Helicobacter pylori- associated gastritis in the corpus. PURPOSE: To evaluate interleukin (IL)-8 production in the gastric corpus mucosa before and during acid-suppressive therapy in H pylori-infected patients. PATIENTS AND METHODS: Ten patients with reflux esophagitis (five H pylori-positive and five H pylori-negative) were treated with omeprazole 20 mg. Serum gastrin concentrations, H pylori colonization density and mucosal IL-8 levels in the corpus were investigated at entry and two weeks after starting therapy. IL-8 levels were measured by ELISA. The organism density was determined, and scored according to area occupied by the bacterial colonies. The presence of H pylori was assessed by rapid urease testing and histological finding of gastric biopsy specimens. RESULTS: In H pylori-positive patients, concentrations of IL-8 during therapy significantly exceeded those before therapy (36.2+/-6. 8 versus 18.3+/-3.8 pg/mg protein; P<0.05) without altering H pylori density. In H pylori-negative patients, IL-8 levels were similar before and during therapy (6.1+/-2.7 versus 6.3+/-3.0 pg/mg protein). Concentrations of gastrin during therapy were significantly higher than those before therapy in all patients. CONCLUSIONS: The results suggest that acid suppression increases mucosal IL-8 levels in H pylori-infected patients with reflux esophagitis.     

Effect of age and Helicobacter pylori infection on gastric acid secretion

BACKGROUND: Whether gastric acid secretion decreases with age is still controversial. With the discovery of Helicobacter pylori, the association of this bacterium with gastric acid secretion has also been discussed. The aim of this study was to investigate the relationship between gastric acid secretion, age and H. pylori infection. METHODS: The presence of H. pylori infection, the grade of fundic atrophic gastritis (FAG), and gastric acid secretion were investigated in 280 subjects without localized lesions in the upper gastrointestinal tract. Helicobacter pylori infection was confirmed by Giemsa and immunohistochemical staining, and FAG of biopsy specimens was graded on a scale of 0-4. RESULTS: Both basal and maximal acid output decreased with age in H. pylori-positive subjects, while they did not change with age in H. pylori-negative subjects. Gastric acid secretion decreased with the progression of FAG. An age-correlated decrease in gastric acid secretion in H. pylori-positive subjects depended on an increasing prevalence of FAG with age. CONCLUSIONS: In the population studied, advancing age had no influence on gastric acid secretion in H. pylori-negative subjects. Gastric acid secretion decreases with age in H. pylori-positive subjects because of the increasing prevalence of FAG with age.     

Reactive oxygen species activity, mucosal lipoperoxidation and glutathione in Helicobacter pylori-infected gastric mucosa

BACKGROUND AND AIM: Helicobacter pylori is considered as the major pathogen in Helicobacter pylori-associated gastroduodenal disease, but the mechanism of its action has not been fully explained. This study was performed to assess the reactive oxygen species activity and the damage in Helicobacter pylori-infected gastric mucosa. METHODS: Gastric biopsy specimens were obtained from 308 patients undergoing endoscopy. Gastric mucosal damage was assessed by using luminol enhanced chemiluminescence, thiobarbituric acid-reactive substance, and mucosal glutathione. RESULTS: The chemiluminescence and thiobarbituric acid-reactive substance-equivalent levels in the mucosa of patients with Helicobacter pylori-positive gastric mucosa (43.8 +/- 134.9 c.p.m./microg tissue, 157.0 +/- 96.2 nmol/g tissue, respectively) were significantly higher than in those with Helicobacter pylori-negative mucosa (6.8 +/- 20.3 c.p.m./microg tissue, 110.0 +/- 51.6 nmol/g tissue, respectively; P=0.000, P=0.016, respectively). The glutathione levels in the mucosa of patients with Helicobacter pylori-positive gastric mucosa (159.3 +/- 76.6 nmol/microg tissue) were significantly lower than in those with Helicobacter pylori-negative gastric mucosa (212.3 +/- 134.3 nmol/microg tissue; P=0.008). After the data were divided according to the presence of Helicobacter pylori, there were no significant differences in chemiluminescence, thiobarbituric acid-reactive substance, and glutathione among the different macroscopic findings within Helicobacter pylori-positive and -negative gastric mucosa. CONCLUSIONS: Helicobacter pylori infection plays a pathological role in many gastrointestinal diseases through excessive mucosal-reactive oxygen species production, pronounced membrane damage, and the depletion of gastric anti-oxidants.     

Gastric Acid Normosecretion Is Not Essential in the Pathogenesis of Mild Erosive Gastroesophageal Reflux Disease in Relation to Helicobacter pylori Status

In the pathogenesis of gastroesophageal reflux disease (GERD), gastric acid is considered to be one of the most important factors, but little is known about the degree of gastric acid secretion in GERD patients. In this study, we evaluated it in GERD patients and control subjects by 24-h intragastric pH, and serological and histological investigations, in relation to Helicobacter pylori (H. pylori) status. In H. pylori-negative GERD patients gastric acid secretion was similar to that in H. pylori-negative control subjects. In H. pylori-positive GERD patients, in particular, mild GERD patients, it decreased significantly compared to that in H. pylori-negative control subjects, but the degree of decrease was smaller than in H. pylori-positive control subjects. Results of serological and histological evaluation were supportive. In conclusion, in some GERD patients, gastric acid secretion was significantly decreased. Increased or maintained gastric acid secretion was not essential in the pathogenesis of mild GERD.     

Helicobacter pylori increases the epithelial permeability to a food antigen in human gastric biopsies

AIMS: We have previously shown that H. pylori increases the passage of intact protein across the digestive epithelium, in vitro and in vivo in mice. The aim of this study was to test whether H. pylori can alter gastric permeability to a food-type antigen in humans. METHODS: Antral and corpus gastric biopsies obtained from H. pylori-positive and H. pylori-negative patients suffering from nonulcer dyspepsia with normal esogastroduodenal endoscopy were mounted in adapted Ussing chambers to measure gastric permeability. Electrical resistance (R, an index of epithelial integrity) and fluxes of 14C-mannitol (JMan, a marker of paracellular permeability) and 3H-horseradish peroxidase (HRP, a test protein of antigen transport and processing) under intact (JHRPi) and degraded (JD) form, across the biopsies, were measured. RESULTS: At the corpus level, biopsies obtained from H. pylori-positive patients, as compared to H. pylori-negative patients, presented significantly higher intact--but not degraded--HRP fluxes (JHRPi = 446 +/- 297 and 219 +/- 265 ng/h cm2, p < 0.05; JD = 4,247 +/- 3,884 and 3,575 +/- 2,594 ng/h x cm2, respectively), and an increase in paracellular permeability (Jman = 0.35 +/- 0.1 vs 0.24 +/- 0.08 micromol/h x cm2, p < 0.02, respectively). At the antrum level, a tendency to increased intact HRP fluxes in H. pylori-positive patients, as compared to H. pylori-negative patients, was observed (JHRPi = 284 +/- 250 vs 207 +/- 203 ng/h x cm2, p < 0.09), without modifications of paracellular permeability. CONCLUSIONS: H. pylori infection increases absorption of an intact food antigen across the corpus gastric mucosa. This phenomenon may contribute to the maintenance of gastric inflammation and could play a role in the development of allergic sensitization to dietary antigens in susceptible individuals.     

Helicobacter pylori infection reduces intraluminal nitric oxide

BACKGROUND: Nitric oxide (NO) plays an important role in gastrointestinal mucosal protection. We have previously shown that Helicobacter pylori infection is associated with a lower concentration of NO in the human stomach. The aim of this study is to explore the pathogenesis of this finding using an animal model. METHODS: Mongolian gerbils were divided into four groups: H. pylori-negative and -positive, each with and without the intraperitoneal addition of superoxide dismutase (SOD). Intraluminal NO and serum nitrate were measured by using a chemiluminescence system. Inducible nitric oxide synthase (iNOS) levels in gastric mucosa were measured by using the NOSdetect Assay Kit. RESULTS: iNOS levels in H. pylori-positive gerbils were significantly greater than in those without infection. Intraluminal NO levels in H. pylori-positive gerbils were significantly lower than those in H. pylori-negative ones and increased after SOD administration. Serum nitrate levels in H. pylori-positive gerbils were significantly greater than those in H. pylori negative ones and decreased after SOD administration. CONCLUSIONS: The low level of NO in the gastric lumen in H. pylori infection is likely a result of superoxide production related to H. pylori-induced inflammation.     

Alteration of sister chromatid exchange frequencies in gastric cancer and chronic atrophic gastritis patients with and without H. pylori infection

AIM： To determine, by counting sister chromatid exchange （SCE） frequencies, whether genetic impairment and DNA damage have an effect on the pathogenesis of gastric cancer （GC）. METHODS： Analysis of SCE is a cytogenetic technique used to show DNA damage as a result of an exchange of DNA fragments between sister chromatids. We analyzed SCE frequency in 24 patients with GC, 26 patients with chronic atrophic gastritis （CAG）, and 15 normal controls. The presence of H pylori was confirmed by urease test, toluidine-blue stain and hematoxylin-eosin stain. RESULTS： SCE was significantly increased in H pylori- negative GC patients, and in H pylori-negative CAG patients compared with controls （7.41 ± 1.36 and 6.92 ± 1.20, respectively, vs 5.54 ± 0.8, P 〈 0.001）. There was no difference in the SCE frequency between H pylori- negative GC patients and H pylori-negative CAG patients （P 〉 0.05）. On other hand, the SCE frequencies in H pylori-positive GC patients were higher than those in H pylori-positive CAG patients （9.20 ± 0.94 vs 7.93 ± 0.81, P 〈 0.01）. Furthermore, H pylori-positive GC patients had a higher SCE frequency than H pylori- negative GC patients （9.20 ± 0.94 vs 7.41 ± 1.36, P 〈 0.001）. Similarly, a significant difference was detected between H pylori-positive CAG patients and H pylori-negative CAG patients （7.93 ± 0.81 vs 6.92 ± 1.20, P 〈 0.05）. CONCLUSION： We suggest the increased SCE in patients reflects a genomic instability that may be operative in gastric carcinogenesis.     

Clinical usefulness of serum pepsinogen II in the management of Helicobacter pylori infection

BACKGROUND: Serum pepsinogen II (sPGII) levels are known to increase during Helicobacter pylori infection. AIM: To assess H. pylori infection and success of H. pylori therapy by means of sPGII levels. METHODS: sPGII levels were determined in 156 H. pylori-positive and 157 H. pylori-negative consecutive patients with dyspeptic symptoms. Additionally, sPGII determination was performed in 70 H. pylori-positive patients 2 months after H. pylori eradication therapy. In 29 of these 70 patients, gastroscopy was performed to evaluate the effect of H. pylori therapy on gastric activity. RESULTS: H. pylori-positive subjects demonstrated a significantly higher mean of sPGII levels than H. pylori-negative subjects (16.8 +/- 7.4 vs. 8.6 +/- 3.7 microg/l; p < 0.001). The best sPGII cut-off for predicting H. pylori infection was 9.93 microg/l (sensitivity 83%, specificity 73%). The best cut-off values to evaluate success of therapy were: sPGII of 9.47 microg/l, a sPGII variation level (difference between baseline and after therapy) of 4.54 microg/l, and a sPGII Deltavalue (sPGII variation divided by sPGII before therapy) of 25% (sensitivity 93%, specificity 91%). CONCLUSIONS: sPGII levels may be used as a reliable marker of H. pylori infection in the initial diagnosis as well as to evaluate H. pylori eradication and subsequent changes in gastric inflammation.     

Absence of nocturnal acid breakthrough in Helicobacter pylori-positive subjects treated with twice-daily omeprazole

BACKGROUND: Proton pump inhibitors (PPIs) taken twice daily do not effectively control night-time intragastric pH; nocturnal acid breakthrough (NAB) (arbitrarily defined as intragastric pH < 4 lasting longer than 1 h) occurs in more than 75% of patients. The effectiveness of PPIs depends rather on the Helicobacter pylori status. OBJECTIVES: To investigate the effectiveness of two regimens of omeprazole in H. pylori-positive subjects as well as the occurrence of NAB. PATIENTS: Fifteen otherwise healthy H. pylori-positive subjects participated in this randomized, crossover, double-blind study. METHODS: Night-time intragastric pH-metry was performed before (baseline) and on day 7 of two treatment courses with omeprazole (1 x 20 mg and 2 x 20 mg). A 14-day (minimum) wash-out period was respected between the two treatment courses. RESULTS: Group medians (10-90% confidence intervals) for night-time intragastric pH (22:30-06:30 h) were as follows: baseline, 2 (1-6.1); 1 x 20 mg, 5 (3.3-6.9; P < 0.001 versus baseline); instead of, 2 x 20 mg, 6.3 (4.9-7.1; P < 0.001 versus baseline, P = 0.02 versus omeprazole 1 x 20 mg). The percentage of time with intragastric pH < 3 was 65.4% during baseline (P < 0.05 versus both omeprazole regimens), 27% with once-daily omeprazole (P = 0.001 versus omeprazole 2 x 20 mg) and 0% with twice-daily omeprazole. NAB occurred in eight (53.3%) subjects with once-daily omeprazole and in no subject taking twice-daily omeprazole. CONCLUSIONS: In H. pylori-positive subjects, twice-daily omeprazole is highly effective in controlling nocturnal intragastric acidity. NAB does not occur in those subjects and there is no need to add bedtime H2-receptor antagonists to this regimen.