External quality assessment programmes for detection of HCV RNA, HIV RNA and HBV DNA in plasma: improved proficiency of the participants observed over a 2-year period.

BACKGROUND AND OBJECTIVES: Two External Quality Assessment Programmes (EQAPs) were run in 2008 and 2009 to evaluate the proficiency of blood centres in detecting, by nucleic acid amplification techniques (NAT), the possible contamination of plasma with hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV). MATERIALS AND METHODS: In the EQAP-2008, three customized panels were designed; each containing positive samples with a viral nominal concentration for the three viruses of about three times the 95% DL of the respective commercial NAT assay. In the EQAP-2009, the proficiency of the participants was evaluated with a single panel, independently on the NAT method used. RESULTS: While 84% (102/122) of the participants in the EQAP-2008 correctly identified the positive and negative samples of the panels, in the EQAP-2009 the percentage of proficient laboratories increased to 97% (118/122). Most importantly, in this 2-year experience, we observed a decrease in the number of pre-/postanalytical errors, from 14 in 2008 to two in 2009. CONCLUSIONS: The design of these two EQAPs allowed participants to assess the performance of the NAT methods applied in their routine screening of blood donations, not only with respect to analytical errors but also to human errors that, despite the high level of automation reached by NAT methods, can still occur.

External quality assessment for the detection of HCV RNA, HIV RNA and HBV DNA in plasma by nucleic acid amplification technology: a novel approach.

BACKGROUND AND OBJECTIVES: In this EQA study a novel approach was used to assess the performance of blood centres and blood product manufacturers in detecting the possible contamination of plasma with HCV, HIV and HBV by NAT. MATERIALS AND METHODS: A panel of 12 samples, three negative and three positive for each virus, was distributed to the EQA participants. The positive samples were prepared, using the respective WHO standards, in order to obtain a viral concentration of about three times the 95% DL of the methods most commonly used by laboratories involved in blood screening by NAT. Participants were requested to test each sample of the panel on different days, possibly by different operators using their routine NAT assay. RESULTS: Overall, the participants' performance was satisfactory. In particular, 49 of the 59 participants (83%) were able to correctly identify all samples. Regarding the remaining 10 laboratories, in three cases a deviation from the laboratory's procedure that could be attributed to an operator's mistake was observed, in two cases a possible cross-contamination occurred while in the remaining five cases the failure to detect the positive samples couldn't be ascribed to any relevant deviation in the laboratory's procedure. CONCLUSIONS: The novel design of this EQA study allowed participants to verify their day by day activity as the study was carried out in the context of their routine testing. Under these conditions, it was demonstrated that, despite the high level of automation reached by NAT assays, human errors can still occur.

External quality assessment for the detection of blood-borne viruses in plasma by nucleic acid amplification technology: the first human immunodeficiency virus and hepatitis B virus studies (HIV EQA/1 and HBV EQA/1) and the fifth hepatitis C virus study (HCV EQA/5).

BACKGROUND AND OBJECTIVES: This External Quality Assessment (EQA) study was aimed at assessing the proficiency of blood centres and blood product manufacturers in detecting, by nucleic acid amplification technology (NAT), the possible contamination of plasma with hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV). MATERIALS AND METHODS: Three independent panels, one for each virus, were prepared at the Istituto Superiore di Sanità (ISS) by diluting the respective reference preparations. NAT methods used by the EQA participants included polymerase chain reaction (PCR) assays by Roche, transcription-mediated amplification (TMA) assays by Chiron and in-house PCR assays. RESULTS: Forty-three of the 45 participants (95.6%) in the HCV EQA/5 who used a validated method were consistently able to detect a nominal concentration of 100 IU/ml for all six major genotypes. In the case of the HIV EQA/1, all 35 participants detected the samples containing 1000 IU/ml HIV, while five (14.3%) did not identify the samples containing 100 IU/ml HIV. With respect to the HBV EQA/1, all 16 participants correctly identified the positive samples containing either 1000 IU/ml or 100 IU/ml HBV. No false-positive results were observed with any of the three panels. CONCLUSIONS: The HCV EQA/5 showed an improved proficiency of laboratories as compared with the HCV EQA/4. In fact, HCV genotypes 1, 2, 3 and 5 were correctly identified in 100% of the assays and genotypes 4 and 6 in 97.8% of the assays. While most of the participants in the HIV EQA/1 showed a good level of proficiency, an excellent performance was shown by all participants in the HBV EQA/1.

High proficiency in detecting the six major hepatitis C virus genotypes of laboratories involved in testing plasma by nucleic acid amplification technology.

Since the introduction of mandatory HCV RNA testing of plasma pools for fractionation by nucleic acid amplification technology, we have organised External Quality Assessment studies (EQAs) addressed to blood products manufacturers and blood centres. Here we report the results of a new EQA, the first one to include all six major HCV genotypes. The results, reported by laboratories worldwide, showed that genotypes 1, 2 and 3 were correctly identified in 100% of the tests, genotype 4 in 96.7% and genotypes 5 and 6 in 98.3% of the assays. As detection of all HCV genotypes is critical for laboratories involved in testing plasma for HCV, all six genotypes should continue to be included in the next EQA studies.

Hepatitis C virus testing of plasma pools by nucleic acid amplification technology: external quality assessment.

BACKGROUND AND OBJECTIVES: Since 1 July 1999, in accordance with European regulations, only batches of blood products obtained from plasma pools tested and found to be non-reactive for hepatitis C virus (HCV) RNA are being released. As monitoring the performance of manufacturers involved in plasma pool testing is important to ensure reliable amplification techniques, the Istituto Superiore di Sanità, as the Italian regulatory authority, organized an external quality assessment study. MATERIALS AND METHODS: A reference HCV RNA panel calibrated in international units (IU) was sent to each participant to be tested according to the validated procedure they routinely used in plasma pool testing. The panel consisted of 20 coded samples, four of which were obtained from a negative plasma pool. The remaining 16 samples, prepared by diluting the national reference preparation (ISS HCV RNA 0498), represented four half-log dilution series, each consisting of four samples containing 100, 32, 10 and 3.2 IU/ml of HCV RNA. RESULTS: The overall performance of the laboratories was very satisfactory. All laboratories correctly identified the negative samples. The 100- and 32-IU/ml samples were both detected in 98.4% of the assays, while the 10- and 3.2-IU/ml samples were detected in 73.4 and 50.0% of the assays, respectively. No substantial differences were observed between in-house procedures and commercial kits. CONCLUSION: This external quality assessment study showed that manufacturers of blood products have reached a high level of proficiency that fully complies with the European Pharmacopoeia requirements. This finding is reassuring in the context of the safety of blood products.

Effect of Helicobacter pylori eradication on 24-hour gastric pH and duodenal gastric metaplasia.

Published data on the regression of the extent of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection and the normalization of the organism-induced alterations in gastric physiology are scanty and controversial. Therefore, we decided to assess the circadian pattern of gastric acidity and the degree of DGM before and one year after H. pylori eradication in a group of duodenal ulcer patients. Fifteen consecutive H. pylori-positive patients with endoscopically proven duodenal ulcer were recruited for this study. The diagnosis of H. pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before and one year after H. pylori eradication. At the same time, gastric pH was measured by 24-hr continuous intraluminal recording. H. pylori eradication was ascertained by means of concomitant negative CLO-test and histology performed both four weeks after the end of the eradicating treatment and at the one-year endoscopic control. After successful cure, all patients discontinued any antiulcer medication. The mean 24-hr gastric pH was 1.7 +/- 0.4 before and 1.6 +/- 0.4 after one year of H. pylori eradication (P = 0.75). DGM improved in three cases, worsened in four cases, and was unchanged in eight cases at the one-year control (P = 0.87). No correlation was found between 24-hr gastric pH and DGM (P = NS) both at baseline and one year after eradication. Our results show that neither circadian gastric acidity nor DGM change significantly one year after H. pylori eradication in duodenal ulcer patients. Thus, the disappearance of H. pylori infection does not determine any increase in gastric pH and any reversal of gastric-type epithelium in the duodenum.

The impact of antibiotic resistance on the efficacy of three 7-day regimens against Helicobacter pylori.

BACKGROUND: Antibiotic resistance affects the success of anti-Helicobacter pylori therapies and varies greatly from country to country. AIM: To compare the efficacy of three short-term triple regimens in relation to H. pylori primary resistance in our region. METHODS: We enrolled 210 H. pylori-positive dyspeptic patients for this randomized, open, parallel-group study. Three arms of 70 patients each received the following 1-week regimens: (1) ranitidine bismuth citrate 400 mg b.d. + clarithromycin 250 mg b.d. + metronidazole 500 mg b.d. (RCM); (2) bismuth subcitrate 240 mg b.d. + amoxycillin 1000 mg b.d. + metronidazole 500 mg b.d. (BAM); (3) omeprazole 20 mg o.d. + clarithromycin 250 mg b.d. + metronidazole 500 mg b.d. (OCM). H. pylori was assessed by CLO-test and histology before and 4 weeks after therapy. Antibiotic resistance was assessed by E-test. RESULTS: On intention-to-treat analysis RCM was more effective than OCM (84% vs. 69%; P < 0.03) and BAM (84% vs. 63%; P < 0.004). MIC determination was successful in 117 out of 210 patients (55%); metronidazole resistance was present in 52 out of 117 patients (44%) and clarithromycin resistance was present in 17 out of 117 patients (14%). Excellent cure rates were achieved when strains were sensitive to both antibiotics (100% with RCM and BAM and 90% with OCM), whereas RCM was superior to OCM (P=0.009) and BAM (P=0.001) with respect to overall resistant strains (94% vs. 57% and 38%, respectively). CONCLUSIONS: One-week RCM is the best regimen to eradicate H. pylori in our geographical area. This seems to be linked to the better ability of RCM compared to OCM and BAM in overcoming the high prevalence of H. pylori resistance to both metronidazole and clarithromycin in our region.

Effect of gastric acid suppression on 13C-urea breath test: comparison of ranitidine with omeprazole.

BACKGROUND: The assessment of the effect of H2 antagonists on the results of the urea breath test has produced controversial results. AIM: To assess whether standard doses of both omeprazole and H2 blockers can adversely influence the accuracy of the urea breath test. METHODS: Sixty dyspeptic patients with ascertained Helicobacter pylori infection were recruited for this prospective, open study. They were randomized to receive either omeprazole 20 mg at 08:00 hours (n = 30) or ranitidine 300 mg at 22:00 hours (n = 30) for 14 days. The urea breath test was performed at baseline, on day 14, while patients were still taking the antisecretory drugs, and on day 21, 1 week after their cessation. Duplicate breath samples were collected after ingestion of 75 mg 13C-urea + citric acid. A delta value > 5 per thousand was considered positive. RESULTS: On day 14 the median delta values had declined, but not significantly (P = 0. 07) compared to baseline (13.79 vs. 22.39) with omeprazole, while they had increased (P = 0.27) with ranitidine (27.21 vs. 19.46). On the same day there were five out of 30 (17%) and five out of 28 (18%) false-negative results in the omeprazole and ranitidine groups, respectively. All these cases became positive again on day 21. However, in eight cases treated with omeprazole and 13 treated with ranitidine, there was an increase of 14-day delta values compared to baseline. CONCLUSIONS: Our study shows that both omeprazole and ranitidine at standard doses are able to negatively affect the results of the urea breath test. Their adverse effect resolves within 7 days of drug cessation and therefore the withdrawal of these drugs 7 days before testing seems to be sufficient to avoid false-negative results. The surprising finding that both antisecretory drugs reduce delta values in one group and increase them in another group of patients deserves further study.

Prevalence of TT viral DNA in italian blood donors with and without elevated serum ALT levels: molecular characterization of viral DNA isolates.

BACKGROUND AND OBJECTIVE: A novel non-enveloped DNA virus, called TT virus (TTV), has been reported to be associated with post-transfusion hepatitis of unknown etiology. Although its clinical role still remains obscure, its presence in blood donations might cause problems. It, therefore, appeared of interest to investigate TTV prevalence in voluntary blood donors. DESIGN AND METHODS: A total of 595 Italian blood donors with and without elevated serum alanine aminotransferase (ALT) levels were tested by polymerase chain reaction using two sets of semi-nested primers that amplify the well-known region in the N22 clone. The amplified products were then sequenced to assess the genotype by phylogenetic and restriction fragment length polymorphism analyses. RESULTS: The prevalence of TTV in blood donors was 5+/-1.9% (25 out of 500) with a 95% confidence limit. A similar prevalence was found in 95 selected blood donors with increased ALT levels. A viral load of 10(3)-10(4) viral DNA molecules/mL was found, thus indicating a rather narrow range of variability. A phylogenetic tree built up on the basis of 210 base sequences of ORF1 allowed isolates to be classified into 2 groups corresponding, at least, to two of the putatives TTV genotypes, group 1 and group 2 of Okamoto's classification. A similar classification was also obtained by site restriction enzyme analysis. INTERPRETATION AND CONCLUSIONS: The results show that TTV infection is present among Italian blood donors. No significant difference in prevalence of TTV infection was found between patients with normal and increased ALT, making the association between TTV infection and human hepatitis questionable.

Prevalence of TT virus in plasma pools and blood products.

A high prevalence of TT virus (TTV), a novel virus recently identified in the serum of a patient with post-transfusion hepatitis of unknown aetiology, has been reported in blood donors worldwide. We investigated the presence of TTV DNA in several lots of blood products and in the corresponding plasma pools. In the process, we determined, from three sets of primers, the one which was most efficient in detecting the viral nucleic acid. This set amplifies the region closest to the 3'-end of the TTV genome which was proved, by sequence analysis, to be more conserved than the other two regions. Whereas all 10 intravenous immunoglobulin and 21 albumin batches were TTV negative, 4/5 factor VIII concentrates and 4/10 intramuscular immunoglobulin batches were TTV positive. A high prevalence of TTV DNA (70%) was found in the plasma pools that were collected from four different countries. These results confirm the worldwide distribution of this virus and show that TTV is removed with a varying efficiency during the manufacture of blood products.

Comparison of isotope ratio mass spectrometry and nondispersive isotope-selective infrared spectroscopy for 13C-urea breath test.

OBJECTIVES: The 13C-urea breath test (UBT) is a sensitive and noninvasive method to diagnose Helicobacter pylori infection, but mass spectrometry (IRMS) is very expensive. The aims of this study were to compare the new low-priced infrared spectroscopy with IRMS in detecting the infection and to assess the influence of feeding on test accuracy. METHODS: One hundred thirty-four patients with dyspeptic symptoms were recruited. Of these, 74 were infected and 60 uninfected on the basis of both CLO-test and histology. A subgroup of 37 patients (22 H. pylori-positive and 15 H. pylori-negative) was studied under fasting and nonfasting conditions on two different days. Duplicate breath samples were analyzed with two IRMS systems (Breath Mat and ABCA) and an infrared spectrometer (IRIS) before, 15 min, and 30 min after ingestion of 75 mg 13C-urea with citric acid. In 37 patients the test was repeated the day after the fasted one and was performed 60 min after a meal of 800 Kcal. RESULTS: There was a close correlation between IRIS and Breath Mat (r = 0.969 at 15 min and r = 0.977 at 30 min; p < 0.0001), IRIS and ABCA (r = 0.963 at 15 min and r = 0.985 at 30 min; p < 0.0001), and Breath Mat and ABCA (r = 0.987 at 15 min and r = 0.981 at 30 min; p = 0.0001). The sensitivity ranged from 97-100% at both times with all devices, although the specificity was slightly inferior with the infrared system than with the two IRMS machines (95% vs 98-100% at 30 min), but the difference was not significant (p = NS). Food intake produced three false negative results in all three machines and a systematic shift to lower 6 values in infected patients. CONCLUSIONS: Infrared spectroscopy can be considered a valid alternative to mass spectroscopy for the diagnosis of H. pylori infection. Fasting is required to guarantee an accurate test.

Head-to-head comparison of 1-week triple regimens combining ranitidine or omeprazole with two antibiotics to eradicate Helicobacter pylori.

BACKGROUND: Triple therapies containing omeprazole and ranitidine have been shown to be equivalent in eradicating H. pylori infection, but have been assessed either separately or head-to-head, only in small trials. AIM: To carry out a large randomized controlled study comparing omeprazole and ranitidine combined with two antibiotic combinations for 1 week. METHODS: Three hundred and twenty H. pylori-positive patients were randomly subdivided into four equal-sized groups and received one of the following treatments: OAM = omeprazole 20 mg b.d. + amoxycillin 1 g b.d. + metronidazole 500 mg b.d.; RAM = ranitidine 300 mg b.d. + amoxycillin 1 g b.d. + metronidazole 500 mg b.d.; OAC = omeprazole 20 mg b.d. + amoxycillin 1 g b.d. + clarithromycin 250 mg t.d.s.; RAC = ranitidine 300 mg b.d. + amoxycillin 1 g b.d. + clarithromycin 250 mg t.d.s. The assessment of H. pylori status was performed before and 4 weeks after the end of therapy by means of CLO-test and histology. H. pylori infection was considered to be eradicated when both tests were negative. RESULTS: OAM and RAM eradicated H. pylori in 89% and 85% of cases on per protocol (P = 0.48) and in 77% and 75% of cases on intention-to-treat analyses (P = 0.71). OAC and RAC eradicated H. pylori in 67% and 70% of cases on per protocol (P = 0.68) and in 57% and 64% of cases on intention-to-treat analyses (P = 0.41). In contrast, there was significant difference between OAM and OAC (P<0.01) and between RAM and RAC (P<0.05). Side-effects occurred in 15%, 10%, 17% and 16% of patients with respect to the above four subgroups. CONCLUSIONS: Omeprazole and ranitidine combined with two antibiotics for 1 week are equally effective in the eradication of H. pylori infection, and these results question the role of profound acid suppression in the eradication of the bacterium.

Histological and functional recovery in patients with multifocal atrophic gastritis after eradication of Helicobacter pylori infection.

BACKGROUND/AIMS: To assess the effect of Helicobacter pylori eradication on gastric histology and physiology in patients with multifocal atrophic gastritis over 1-year period. PATIENTS: Fourteen consecutive patients with histological evidence of chronic gastritis and Helicobacter pylori infection diagnosed by histology and serology entered this study. Patients with pernicious anaemia, gastric ulcer or carcinoma, duodenal ulcer, reflux oesophagitis and regular intake of nonsteroidal anti-inflammatory drugs were excluded. METHODS: Patients underwent triple anti-Helicobacter treatment for one week, which resulted successful in all subjects on the basis of negative CLO test and histology as well as 50% decrease in IgG antibodies after 4 weeks and 6 months of treatment, respectively. Histological and functional investigations were performed at baseline, 6 and 12 months after Helicobacter pylori eradication. Histological assessment of inflammatory cell infiltrates was performed on multiple biopsy specimens of the corpus and fundus. Functional tests were 24-hour continuous gastric pH-metry, fasting serum gastrin assay and pepsinogen I levels. RESULTS: There was a progressive significant improvement (p < 0.01-0.001) in acute and chronic inflammatory cell infiltrates in the gastric mucosa throughout the 12-month period. Functional recovery with increase in gastric acidity (p < 0.01) and decrease in gastrin and pepsinogen I levels (p < 0.001) was more evident at the 6-month than at the 12-month checkpoint after Helicobacter pylori eradication (p = NS for gastric pH and p < 0.02 for the other two variables) between 6 and 12 months. CONCLUSIONS: Eradication of Helicobacter pylori infection significantly improves the inflammatory status of oxyntic mucosa and this promotes an almost complete functional recovery. However, the non-parallel behaviour of gastric acidity, which was maximal at 6-month checkpoint, and histological parameters which continued to improve throughout the entire 12-month observation period, seems to indicate that removal of acid-inhibitory substances induced by Helicobacter pylori infection was also responsible for the more rapid recovery of gastric secretory function.

Optimal duration of therapy combining ranitidine bismuth citrate with clarithromycin and metronidazole in the eradication of Helicobacter pylori infection.

BACKGROUND: Ranitidine bismuth citrate (RBC) co-prescribed with clarithromycin and metronidazole for 1 week has been shown to be an effective eradicating regimen for Helicobacter pylori. AIM: To determine the optimal duration of this regimen. METHODS: A series of 165 dyspeptic patients were recruited for this randomized, open, parallel-group study. They were subdivided into three groups receiving RBC 400 mg b.d. plus clarithromycin 250 mg b.d. and metronidazole 500 mg b.d. for three different periods (4, 7 and 10 days). H. pylori infection was assessed by the concomitant positivity of CLO-test and histology performed at the pre-entry endoscopy. The bacterium was considered eradicated on the basis of a negative 13C-urea breath test performed at least 28 days after the completion of treatment. RESULTS: The three subgroups were well matched and 16 patients dropped out of the study for many reasons (six in the 4-day, five in the 7-day and five in the 10-day treatment regimens). Intention-to-treat cure rates were 60%, 84% and 85%, and the per-protocol rates 67%, 92% and 94% in the 4-day, 7-day and 10-day treatment regimens, respectively. There was a significant difference, P = 0.003-0.006 on intention-to-treat and P = 0.001-0. 002 on per protocol analysis between the 4-day and the 7-day and the 4-day and the 10-day periods, respectively. The 7-day and 10-day periods did not differ from each other. Side-effects were reported in 9%, 14% and 20% of the 4-, 7- and 10-day regimens. They led to stopping treatment in four cases (one in the 7-day and three in the 10-day period). There was no statistical difference among them. CONCLUSIONS: Reducing the duration of RBC-based triple therapy to 4 days provides a low and unacceptable rate of H. pylori eradication. As there is no difference between 7 and 10 days of treatment, 1 week represents the optimal time period for this kind of treatment, based on RBC plus two antibiotics.

Effect of one-month treatment with nonsteroidal antiinflammatory drugs (NSAIDs) on gastric pH of rheumatoid arthritis patients.

The use of NSAIDs is strongly associated with peptic ulceration. The inhibition of prostaglandin synthesis with the consequent increase of gastric acidity is considered a possible mechanism. Therefore we decided to assess the effect of one-month treatment with NSAIDs on the circadian gastric pH of rheumatoid arthritis (RA) patients. We studied 11 consecutive patients (one man and 10 women, median age 55, range 26-72 years) with confirmed RA. None was H. pylori positive. A 24-hr gastric pH recording was performed both in basal conditions and after one-month treatment with either indomethacin 150 mg/day (eight cases) or ketoprofen 300 mg/day (three cases). Only the 10 female patients were eligible for final analysis, and six matched healthy subjects not taking NSAIDs were used as control group. The number of 24-hr pH readings for various pH thresholds was calculated for both populations. The highest acid levels (pH < 3.0) did not differ between the two pH profiles of the control group (7440 vs 7391, P = NS), while they predominated after the one-month NSAID treatment (10,339 vs 11,440, P < 0.001) in RA patients. These findings show that there is an increased gastric acidity after one-month of treatment with NSAIDs in female patients with RA of recent onset. This may sustain the rationale of using antisecretory agents to prevent gastroduodenal ulcerations in these patients.

Comparison of 24-h control of gastric acidity by three different dosages of pantoprazole in patients with duodenal ulcer.

BACKGROUND: It is now clear that the extent to which gastric acid secretion must be suppressed varies with the clinical condition being treated. AIM: To assess the 24-h control of gastric acidity and the individual response variability of three different doses of pantoprazole. METHODS: Sixty-four duodenal ulcer patients were recruited for this prospective, randomized, multicentre, double-blind, parallel-group study. They were subdivided into three well-matched groups treated with 20 mg o.m., 40 mg o.m. and 40 mg b.d. of pantoprazole, respectively. Endoscopy and intragastric pH monitoring were performed in each patient before and after 14 days of treatment. RESULTS: Fifty-five patients were eligible for final analysis (17 treated with 20 mg o.m., 18 with 40 mg o.m. and 20 with 40 mg b.d. pantoprazole). The ulcer crater healed in 94, 88 and 95% of cases, respectively. The three dosages of pantoprazole produced significant increases in gastric pH compared to basal levels (P < 0.0001). There was also a clear dose-dependent pharmacodynamic effect, which augmented on moving from the lowest dosage of 20 mg o.m. pantoprazole to the highest dosage of 40 mg b.d. (P < 0.01-0.001). The inter-individual response variability within the three treatment groups was more marked with the dose of 20 mg than with the two higher doses of pantoprazole. CONCLUSIONS: All three doses of pantoprazole we tested are highly effective in decreasing gastric acidity and there is a clear dose-dependent pharmacodynamic effect on moving from the lowest to the highest dosage. The greatest inter individual variation in the degree of acid inhibition was seen with pantoprazole 20 mg o.m., while the majority of patients responded adequately to the two higher doses of the drug.

Transient global brain hypoxia-ischemia in adult rats: neuronal damage, glial proliferation, and alterations in inositol phospholipid hydrolysis.

A model of ischemic-hypoxic brain injury which combines bilateral occlusion of common carotid arteries for 10 min and mild hypoxia (15% O2 for 10 min before and during occlusion) was developed. Global ischemia was assessed by a simplified EEG recording indicating isoelectric line, i.e. full arrest of cortical electrical activity. Histological examination of brain 7 days after ischemic insult showed from moderate to severe damage, mainly in the cerebral cortex (layers III, V and VI) and hippocampus (mainly CA1 subfield). The injury consisted of neuronal degeneration and necrosis with nuclear pyknosis and karyorrhexis. Immunohistochemical staining for gliofibrillar acidic protein showed a marked glial proliferation in the cerebral cortex and hippocampus. In the cortical slices, inositol phosphates accumulation stimulated by excitatory amino acid agonists (ACPD, ibotenate and quisqualate), as well as by norepinephrine and carbachol, was enhanced significantly (p < 0.01) with respect to sham-operated rats 7 days, but not 24 h, after the ischemic insult. The overall data show that the relatively simple transient brain hypoxia/ischemia rat model produces full arrest of cortical EEG, histopathological alterations and those relative to post-receptor neurochemical mechanisms characteristic of four-vessel occlusion model.