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Biomedical subjects

D Vaira

Publications and source records attributed to D Vaira.

At least 91 records · Page 5Linked to original sources
PubMed1997

High prevalence of Helicobacter pylori in liver cirrhosis: relationship with clinical and endoscopic features and the risk of peptic ulcer.

In 153 consecutive patients with cirrhosis we assessed: (1) the prevalence of IgG to Helicobacter pylori and compared it with that found in 1010 blood donors resident in the same area; and (2) the relationships of IgG to Helicobacter pylori with clinical and endoscopic features and with the risk of peptic ulcer. The IgG to Helicobacter pylori prevalence of cirrhotics was significantly higher than in blood donors (76.5% vs 41.8%; P < 0.0005) and was not associated with sex, cirrhosis etiology, Child class, gammaglobulins and hypertensive gastropathy. In both groups, the prevalence of IgG to Helicobacter pylori was significantly higher in subjects over 40. Among patients with cirrhosis a significantly higher prevalence of Helicobacter pylori was found in patients with previous hospital admission (P = 0.02) and/or upper gastrointestinal endoscopy (P = 0.01) and patients with peptic ulcer (P = 0.0004). Multivariate analysis identified increasing age and male sex as risk factors for a positive Helicobacter pylori serology and no independent risk factors for peptic ulcer. The high prevalence of Helicobacter pylori-positive serology found in the present series is related to age and sex and might also be explained by previous hospital admissions and/or upper gastrointestinal endoscopy. Our results do not confirm the role of Helicobacter pylori as risk factor for peptic ulcer in patients with liver cirrhosis.

Adult↗
PubMed1997

A serologic survey of Helicobacter pylori infection in 3281 Italian patients endoscoped for upper gastrointestinal symptoms. The Italian Helicobacter Pylori Study Group.

AIM: To assess the seroprevalence of Helicobacter pylori infection in a large series of patients with upper gastrointestinal symptoms referred for their first upper gastrointestinal endoscopy, and to evaluate any association with disease. METHODS: A large survey of 3281 dyspeptic patients undergoing their first endoscopic examination was undertaken, involving 93 centres in Italy. A blood sample was taken from each participant, for measuring IgG antibodies against H. pylori using a commercially available kit, and two biopsies of the antral gastric mucosa were obtained for evaluating a Giemsa-stained specimen. RESULTS: Endoscopic macroscopic diagnoses included normal mucosa (25.3%), gustroduodenitis (51.6%), gastric and duodenal ulcers (3.7 and 14.9%, respectively) and other conditions, including gastric cancer (0.8%). Overall, the seroprevalence result was 71.3% with a strong positive association with increasing age and male sex and a negative one with educational level. According to endoscopic diagnoses, the association with H. pylori seropositivity was highest for duodenal and gastric ulcer (multivariate odds ratio: 6.1 and 2.2) and lowest for carcinoma. The comparison between the results of serology and the single Giemsa-stained specimen showed good reliability of H. pylori IgG, particularly in a subgroup (n = 2056) for which the interpretation was performed by a single dedicated pathologist: sensitivity and specificity were 92 and 78%, respectively. CONCLUSION: Commercial IgG serology is a reliable tool for the assessment of H. pylori infection in large-scale multicentre surveys. A very high seroprevalence among dyspeptic patients was confirmed, particularly in the presence of peptic disease. Factors associated with the infection were very similar to those usually reported in the general population, but male patients showed a significantly higher prevalence.

Adolescent↗
PubMed1997

Prospective screening of dyspeptic patients by Helicobacter pylori serology: a safe policy? The Italian Helicobacter pylori Study Group.

BACKGROUND AND STUDY AIMS: Endoscopic screening of all dyspeptic patients is not cost-effective, nor is it feasible in many health-care delivery systems. To select the most appropriate candidates, various preendoscopic screening strategies have been proposed, some of which include Helicobacter pylori serology and patient age. We assessed the value of these two criteria in preendoscopic screening of a large series of dyspeptic patients, and compared the results obtained in a referral hospital (university center with an extensive H. pylori research program) with those in nonreferral hospital (participating centers that did not have such a program). PATIENTS AND METHODS: Blood samples for determination of anti-H. pylori IgG antibody were collected from patients with uninvestigated dyspepsia undergoing endoscopy at one referral hospital and in 93 nonreferral hospitals throughout Italy. For IgG antibody assay, an in-house enzyme-linked immunosorbent assay (ELISA) technique was used in the referral hospital, while a commercial kit was used in the nonreferral hospitals. RESULTS: A total of 1638 patients were evaluated at the referral hospital (845 men and 793 women, mean age 46.1 years, range 18-89), and 3281 at the nonreferral hospitals (1718 men and 1563 women, mean age 48.8, range 18-96), respectively. If endoscopy had not been performed in patients who were seronegative for H. pylori and younger than 45 years, 19% versus 17.5% of the tests would have been avoided in the referral and nonreferral hospitals, respectively, while six of 304 ulcers (2%) and no cancers would have been missed versus 35 of 557 ulcers (6.3%) and two of 557 cancers (0.3%). CONCLUSIONS: A screening strategy based on age and H. pylori serology is a valid means of selecting dyspeptic patients for endoscopy; however, the policy needs further refinement for use in nonreferral hospitals.

Adolescent↗
PubMed1997

Usefulness of serology in preendoscopic screening. The Italian Helicobacter pylori Study Group.

BACKGROUND: Over the last 20 years, upper gastrointestinal endoscopy has become the investigation of choice for patients with symptoms referrable to the upper gastrointestinal tract. As the increasing number of patients referred for endoscopy has led to enlarged waiting lists and medical expenses, it has been recommended that preendoscopic screening strategies might identify patients at low risk of having major pathology. These patients could avoid prompt endoscopy and might safely undergo different management. Since the recognition of the major role played by Helicobacter pylori in gastroduodenal pathology, H. pylori serological and demographical features have been proposed as part of preendoscopic screening strategies in dyspeptic patients referred to endoscopy, in an attempt to reduce endoscopic workload and medical expenses. METHODS: We evaluate data presented in the literature and aim to give interpretations possibly helpful in the clinical practice. RESULTS: The analysis of the endoscopic findings showed that applying a preendoscopic strategy based on age and H. pylori status in local hospitals without a specific interest in H. pylori research would have meant missing a proportion of relevant pathology: 35 of 557 (6.3%) peptic ulcers (24 duodenal and 11 gastric ulcers) and two gastric cancers (0.3%). CONCLUSIONS: Although we do understand the need to increase the cost-effectiveness of endoscopy and realize that considering age and H. pylori status could help to get to this target, we conclude that similar preendoscopic screening strategies must be refined further before being adopted on a large scale.

Endoscopy, Gastrointestinal↗
PubMed1997

Family treatment of symptomatic children with Helicobacter pylori infection.

BACKGROUND: Familial clustering of Helicobacter pylori infection has been reported. We tested the hypothesis that simultaneously treating all Helicobacter pylori positive family contacts of infected symptomatic children results in lower treatment failure. METHODS: Relatives of 47 children (index) with Helicobacter pylori gastritis had endoscopy to assess prevalence of infection in first degree cohabiting relatives. Controls included 60 children with dyspepsia and Helicobacter pylori gastritis whose infected family contacts were not treated. Index children, siblings younger than 18 years of age and control children received a 2-week course of amoxicillin and tinidazole. Parents of index children and their siblings over 18 years of age received a 2-week course of Colloidal Bismuth Subcytrate and tinidazole. The eradication rate in index children and their relatives was compared to controls whose infected family contacts were not treated. RESULTS: Helicobacter pylori was found in 67% of 31 siblings younger than 18, in 82% of 22 siblings older than 18 years, and in 87% of 92 parents. Endoscopy, repeated four to six weeks after the end of treatment, showed Helicobacter pylori eradication in 94% of children and siblings younger than 18, and in 70% of parents and siblings over 18 years in the family treatment group, compared with 75% of control children (p < .01). CONCLUSIONS: The high prevalence of the infection in family members suggests that person-to-person spread of Helicobacter pylori takes place. Furthermore our results show that if (or when) required, simultaneous treatment given to the whole family results in lower treatment failure, since it may promote compliance to treatment.

Adolescent↗
PubMed1996

Serological response to Helicobacter pylori in gastric and non-gastric cancer.

1. We aimed to evaluate the seroprevalence of Helicobacter pylori (H. pylori) in gastric cancer, non-gastric cancer and outpatients by ELISA and iso-electric focusing, and to compare histology and serology for H. pylori in gastric cancer and outpatients. 2. In 124 patients with gastric cancer, 78 patients with non-gastric cancer and 110 outpatients, H. pylori seroprevalence was assessed by ELISA and isoelectric focusing. Gastric cancer and outpatients underwent endoscopy with biopsies. 3. Seroprevalence by ELISA was significantly higher in gastric cancer compared with non-gastric cancer (84% versus 56%, P < 0.001) but not with outpatients (84% versus 74%). Iso-electric focusing detection of H. pylori was comparable to ELISA: 85, 51 and 75% in gastric cancer, non-gastric cancer and outpatients respectively. Oligoclonal iso-electric focusing was significantly more frequent in gastric cancer compared with non-gastric cancer and outpatients: 69% versus 45 and 46% respectively, P < 0.01. The reliability of H. pylori detection by antral biopsy was significantly lower in gastric cancer compared with outpatients: 36% versus 74% (P < 0.001). In gastric cancer, ELISA and iso-electric focusing were significantly more reliable than histology in H. pylori detection (84 and 85% versus 36% respectively) (P < 0.001). 4. Serological immune response to H. pylori in gastric cancer, non-gastric cancer and outpatients seems different both quantitatively and qualitatively; serology was more reliable than histology in detection of H. pylori in gastric cancer.

Adult↗
PubMed1996

Antigenic mimicry between Helicobacter pylori and gastric mucosa in the pathogenesis of body atrophic gastritis.

BACKGROUND & AIMS: The majority of patients with Helicobacter pylori infection have autoantibodies cross-reacting with gastric antigens. In this study, the relation between autoantibody status, histopathology of body mucosa, and antigenic profile of H. pylori was investigated. METHODS: One hundred patients were examined for H. pylori infection, body gastritis, and gastric autoantibodies. Balb/c mice were analyzed for serum autoantibodies after immunization with H. pylori from patients with and without atrophic gastritis. RESULTS: Immunoglobulin G autoantibodies were detected in 57 of the 87 infected patients (65.5%) but in none of the 13 patients without infection and gastritis. The autoreaction involved mainly the luminal surface of glandular cells and secretory canaliculi of parietal cells. The autoantibody status correlated with the presence and degree of inflammation and atrophy of the glands. H. pylori from patients with atrophic gastritis showed a higher capacity to induce autoantibodies than H. pylori from patients with a minimal superficial gastritis. Monoclonal antibodies showed differences in the bacterial expression of cross-reacting determinants. CONCLUSIONS: H. pylori-mediated autoimmunity is involved in the pathogenesis of chronic atrophic gastritis. The grade of antigenic mimicry of the infecting H. pylori strain plays a role in the progression of chronic gastritis to atrophy.

Adolescent↗
PubMed1996

Prevention with sucralfate gel of NSAID-induced gastroduodenal damage in arthritic patients.

OBJECTIVES: To evaluate the efficacy of a new formulation of sucralfate as gel (Gastrogel) in the short-term prevention of gastroduodenal lesions in arthritic patients receiving nonsteroidal anti-inflammatory drugs. METHODS: One hundred seven patients with arthritis (M/F 18/89, mean age 55.2 +/- 9.7 yr) enrolled in two centers were considered eligible for the study if initial endoscopy showed the absence of any relevant mucosal damage. Patients were randomly allocated to receive diclofenac 200 mg/day or naproxen 1 g/day plus either sucralfate gel 1 g b.i.d. (N = 53) or identical placebo (N = 54) for 14 days in a randomized double-blind study. Repeated assessment of GI symptoms and endoscopy were performed at the end of the study period. RESULTS: At final endoscopy the incidence of erosion and the mean endoscopic score for both stomach and duodenum were significantly lower in the sucralfate gel group compared with placebo group (p < 0.05). Both heartburn and epigastric pain were significantly less frequent in patients receiving sucralfate gel than placebo (51 vs 30% and 49 vs 28% for heartburn and epigastric pain, respectively, p < 0.05). No differences were observed in the incidence or in the mean score for nausea. An unexplained difference in the incidence of ulcers was found between the two centers, but in both a similar reduction in the incidence of ulcers was observed between patients receiving sucralfate gel compared with those receiving placebo. The overall difference (8% in sucralfate-treated patients, 28% in patients receiving placebo) of gastroduodenal ulcers was statistically significant (p < 0.05). CONCLUSIONS: Sucralfate gel reduces both the incidence of acute gastroduodenal mucosal lesions and symptoms in patients with arthritis receiving short-term nonsteroidal anti-inflammatory drugs.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1995

Helicobacter pylori status, endoscopic findings, and serology in HIV-1-positive patients.

We have carried out a large prospective study of the frequency of H. pylori infection and HIV-1 status in a community of ex-drug abusers including subjects with (N = 210) and without (N = 259) upper gastrointestinal symptoms, endoscopy and serology. Control groups were patients with upper gastrointestinal symptoms not at high risk of HIV-1 infection (N = 219) and asymptomatic blood donors (n = 322). H. pylori was present in 52% of symptomatic community residents having endoscopy and 55% of the control patients with symptoms but not at high risk of HIV-1 infection. H. pylori was less common in HIV-1-positive patients (40%) than those who were negative (66%; P < 0.001). In patients with AIDS (33%), the frequency of H. pylori infection was reduced compared to HIV-1-positive patients without AIDS (53%; P = 0.05). All the residents with AIDS had upper gastrointestinal symptoms. In community residents, peptic ulcer was always associated with H. pylori infection. By H. pylori serology, there was no difference in the frequency of infection in asymptomatic residents (56%) whether HIV-1 positive (55%) or HIV-1 negative (58%) compared with those residents with symptoms. Overall, H. pylori was less common in HIV-1-positive residents (49%) than those who were HIV-1 negative (61%; p < 0.05). This difference was due mainly to the low frequency of infection in residents with AIDS (33%). H. pylori infection is common in HIV-1 positive patients, and only slightly reduced when compared with at-risk HIV-1-negative subjects. Peptic ulcer is associated with H. pylori in HIV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1995

Standardisation of primers and an algorithm for HIV-1 diagnostic PCR evaluated in patients harbouring strains of diverse geographical origin. The Belgian AIDS Reference Laboratories.

Eight Belgian AIDS Reference Laboratories established a multicentre quality control to evaluate the performance of their diagnostic human immunodeficiency virus type 1 (HIV-1) DNA polymerase chain reaction (PCR). A set of Belgian and African HIV-1 seropositive and seronegative patient samples, collected in Belgium, and the British Medical Research Council (MRC) HIV-1 PCR reference reagent kit, containing plasmid HIV-1 DNA at several dilutions in human carrier DNA with appropriate negative controls, were tested by the laboratories. No false positive results were reported. All laboratories were able to detect one to two copies of HIV-1 DNA. Among the 17 Belgian and African HIV-1 seropositives, some laboratories reported up to four indeterminate results, mainly due to failure of the SK38-39, SK68-69 (Ou et al. (1988) Science 239, 295-297) and/or gag881-882 (Simmonds et al. (1990) J. Virol. 64, 864-872) primers and a poorly performing algorithm. Only the H1POL4235-4538 nested pol primer set, developed by one of the laboratories, correctly identified all the tested HIV-1 positive and negative samples. Consequently, the laboratories decided to evaluate these pol primers as a reference primer set and to standardise the testing algorithm. All laboratories achieved a sensitivity and specificity of 100% on testing 10 additional Belgian and African patient samples, when adapting a standardised algorithm based on three HIV-1 primer sets, one of which is the H1POL4235-4538 primer set.

Africa↗
PubMed1995

DNA probe hybridisation in microwells using a new bioluminescent system for the detection of PCR-amplified HIV-1 proviral DNA.

A new bioluminescent detection system combined with a sandwich DNA hybridisation reaction in microwells has been developed for the detection of human immunodeficiency virus type 1 (HIV-1) provirus DNA amplified by the polymerase chain reaction (PCR). First, a fragment of the HIV-1 gag gene was amplified. The amplified DNA fragments were denatured and hybridised to a capture probe immobilised in microwells and to a biotinylated detection probe. A streptavidin-pyruvate kinase conjugate could then react on the biotinylated probe and the kinase activity detected by means of the luciferin-luciferase system, with production of a bioluminescent signal. This sandwich assay followed by a bioluminescent reaction detected as little as 7 amol of target DNA. The bioluminescent assay detected 5 HIV copies generated after one round of PCR, even if no band was seen on an agarose gel. The assay was applied to the detection of HIV-proviral DNA in peripheral blood mononuclear cells after one round of PCR and allowed to clearly identify a positive sample as compared to nested PCR.

Base Sequence↗
PubMed1995

The susceptibility of Helicobacter pylori to the rifamycin, rifaximin.

Forty strains of Helicobacter pylori had an MIC(50) of 4 mg/L of the non-absorbably antibiotic, rifaximin. Neither synergy nor antagonism was demonstrated when the drug was combined with ampicillin, metronidazole and omeprazole and the rate of spontaneous mutation was less than 1 in 10(8). With these in-vitro characteristics, rifaximin should now be assessed for clinical efficacy.

Ampicillin↗
PubMed1995

Spectrotypic analysis of antibodies to Helicobacter pylori in patients with antral gastritis and duodenal ulcer.

AIMS: To investigate the anti Helicobacter pylori (H pylori) spectrotype associated with (a) antral gastritis and duodenal ulcer; (b) the H pylori eradicating treatment. METHODS: Spectrotypic analysis was performed by isoelectric focusing and reverse blotting (IEFRB) in a cross sectional study on sera from 70 patients with antral gastritis and duodenal ulcer. In addition, a longitudinal study was performed on 40 of these patients (20 with antral gastritis and 20 with duodenal ulcer) who underwent eradicating treatment. RESULTS: The cross sectional study showed that the oligoclonal spectrotype was present in 74% of antral gastritis patients and in 85% of duodenal ulcer patients. In only a minority of subjects (23% with antral gastritis and 3% with duodenal ulcer) was a polyclonal spectrotype observed. The longitudinal study showed a reduction in the intensity of the spectrotypic bands in 5/10 antral gastritis patients with eradicated H pylori as opposed to only 2/10 patients without eradication. A reduction was also observed in 6/11 eradicated v 0/9 non-eradicated patients with duodenal ulcer. Collectively, a reduction in the spectrotype was observed in 11/21 patients (52%) who--independently of the disease--underwent H pylori eradication, as opposed to 2/19 of the non-responder patients (10.5%). The polyclonal spectrotype was found exclusively in four patients with antral gastritis, all belonging to the group without eradication of H pylori after eradicating treatment. CONCLUSIONS: The anti H pylori oligoclonal spectrotype is the most common pattern observed in patients with antral gastritis and duodenal ulcer. After H pylori eradicating treatment the spectrotype does not change qualitatively, but the polyclonal pattern seems to be predictive of a poor response to eradication.

Adolescent↗