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Biomedical subjects

L Gatta

Publications and source records attributed to L Gatta.

At least 37 records · Page 2Linked to original sources
PubMed2003

Effect of Helicobacter pylori eradication on development of dyspeptic and reflux disease in healthy asymptomatic subjects.

BACKGROUND AND AIM: There are few data on the course of Helicobacter pylori infection in asymptomatic subjects. The aim of this study was to assess the effect of eradication therapy on the development of dyspeptic and gastro-oesophageal reflux disease in a cohort of asymptomatic individuals observed over a prolonged period. METHODS: A total of 169 blood donors infected with H pylori who had volunteered for studies on eradication in 1990 formed the cohort. To be included in this cohort subjects had to have no symptoms, as determined by a validated symptom questionnaire at the baseline visit. Eighty eight subjects were infected with H pylori while 81 had successfully undergone eradication therapy. Subjects were followed up (annually) using the same symptom questionnaire and in 2000 they underwent repeat endoscopy. RESULTS: Thirteen subjects developed symptoms during follow up. The incidence of symptoms in H pylori positive subjects was 1.893/100 person-years of follow up and in H pylori negative individuals 0.163/100 person-years of follow up. H pylori infected subjects were significantly more likely to develop symptoms (log rank test, p=0.003) as well as those infected with CagA positive strains (log rank test, p=0.017). The development of symptomatic gastro-oesophageal reflux disease was no different in individuals with and without eradication (odds ratio 0.57 (95% confidence interval 0.26-1.24); p=0.163). CONCLUSIONS: H pylori eradication prevents the development of dyspeptic symptoms and peptic ulcer disease in healthy asymptomatic blood donors and is not associated with an increase in the incidence of symptomatic gastro-oesophageal reflux disease.

Antibodies, Bacterial↗
PubMed2002

Review article: Helicobacter pylori infection from pathogenesis to treatment--a critical reappraisal.

The main areas of this review are Helicobacter pylori and disease pathogenesis; the relationship of H. pylori to lower gastrointestinal diseases, liver disease and extra-gastrointestinal conditions; the relationship of H. pylori to gastro-oesophageal reflux disease; infection in the very young and very old; diagnostic techniques; and management of H. pylori infections with particular emphasis on eradication regimens and antibiotic resistance.

Adult↗
PubMed2002

Helicobacter pylori infection, anti-cagA antibodies and peptic ulcer: a case-control study in Italy.

AIM: To evaluate the association between infection with specific strains of Helicobacter pylori and peptic ulcer in patients referred for upper gastrointestinal endoscopy. METHODS: One thousand, six hundred and twenty-six consecutive dyspeptic patients, referred to one Endoscopy Unit in Bologna, Italy, were enrolled. For each participant, a blood sample was obtained for the measurement of distinct immunoglobulin G antibodies against H. pylori lysate and cytotoxin associated gene A (cagA). A case-control study included the whole series: patients diagnosed with duodenal (n=275) or gastric (n=71) ulcer were identified and independently compared with controls with non-ulcer dyspepsia (n=1280). RESULTS: H. pylori seroprevalence (at least one positive marker) was associated with increasing age, male sex and a diagnosis of peptic ulcer. This association was stronger with duodenal ulcer (multivariate odds ratio (OR), 5.2; 95% confidence interval (CI), 3.5-7.9) than with gastric ulcer (OR, 2.3; 95% CI, 1.2-4.4). Further analyses showed that H. pylori lysate+/cagA- subjects had a moderately increased risk of duodenal (OR, 3.2), but not gastric (OR, 1.1), ulcer. When cagA+ subjects were separately compared with seronegative patients, there was a six-fold increased risk for duodenal ulcer and a three-fold increased risk for gastric ulcer. CONCLUSIONS: A strong positive association between infection with a cagA+ H. pylori strain and the presence of peptic disease was found. The seroprevalence of anti-cagA antibodies among patients with non-ulcer dyspepsia is so high (41%) to preclude its use as a pre-endoscopic screening test.

Adult↗
PubMed2002

Review article: diagnosis of Helicobacter pylori infection.

Helicobacter pylori (H. pylori) infection can be diagnosed by invasive techniques requiring endoscopy and biopsy (histological examination, culture, polymerase chain reaction) and by noninvasive techniques (serology, urea breath test, urine or blood, detection of H. pylori antigen in stool specimen). At present, no single test can be absolutely relied upon to detect colonization by H. pylori, and a combination of two tests is recommended if feasible. The tests used should depend on the clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy, and the availability of the tests. Some clinical circumstances warrant invasive studies, principally patients with alarm symptoms (bleeding, weight loss, etc.) as well as older patients with new-onset dyspepsia. Endoscopy may also be advisable in patients who have failed eradication therapy and need culture and antimicrobial sensitivity testing to determine an appropriate regimen. Recent studies have also demonstrated that a strategy to 'test and treat' for H. pylori in uninvestigated, young (< 50 years), dyspeptic patients in primary care is safe and reduces the need for endoscopy. Indeed, a number of clinical guidelines recommend noninvasive testing followed by treatment of H. pylori for dyspeptic patients in primary care based on clinical and economic analyses.

Biopsy↗
PubMed2001

Helicobacter pylori: diseases, tests and treatment.

Gastroduodenal disease associated with Helicobacter pylori infection are reviewed as well as the diagnostic approach. Generally, there are by and large two ways in which a diagnosis of infection by Helicobacter pylori can be made: by using either an invasive or non-invasive procedure. The invasive procedures involve endoscopy and biopsy Biopsy is essential since the mucosa may often appear macroscopically normal but, nevertheless, be inflamed. Once a biopsy is obtained histological examination, culture, polymerase chain reaction, detection of the presence of urease activity can be detected. The non-invasive tests that can be used to diagnose the infection are: serology, detection of labelled metabolic products of urea hydrolysis either in the breath (13CO2, 14CO2), the urine or the blood, detection of Helicobacter pylori antigen in stool specimen. At present, no single test is sufficiently reliable to definitely detect colonisation by Helicobacter pylori, and a combination of two is recommended, if feasible. Choice of the test to be used is not straightforward and relies on a series of situations, i. e., clinical setting and local expertise and availability, that the clinician must consider to obtain the best diagnostic yeld. The challenge of Helicobacter pylori eradication is not very easy to obtain. The possible scenario and the use of a new proton pump inhibitor (esomeprazole) are reviewed and discussed.

Dyspepsia↗
PubMed2001

Review article: the transmission of Helicobacter pylori from stomach to stomach.

The mode of transmission of Helicobacter pylori is largely unknown and is a matter of circumstantial evidence and speculation rather than fact. However, the principle evidence is of two sorts: the epidemiological data, providing evidence of possible risk factors associated with transmission, and the identification of potential sources from which H. pylori could be acquired. Evidence exists for several potential sources of infection and several possible modes of transmission, and it is feasible that the transmission of H. pylori varies according to the cultural and demographic circumstances. However, the most likely recognized source for H. pylori is the human stomach, although it is not known by what route the organism is transmitted to the stomach. Evidence suggests close personal contact is important and that acquisition occurs mainly in childhood. This article reviews the evidence for the source of infection and the route of transmission of H. pylori.

Age Factors↗
PubMed2001

How valuable is the application on consensus guidelines in the management of functional gastrointestinal disorders?

When patients complain of problems, physicians are used to look for some physical or physiological abnormality ruling out infections, inflammatory or cancer. Unfortunately, when we talk about functional disorders we usually cannot observe any defects and it is only possible for us to know of them through the words of our patients. Developing criteria and guidelines is not an easy process, in particular for functional gastrointestinal diseases, when no disease-based biological markers exist. It is difficult to define a medical disorder in the absence of a biological "gold standard". The Rome II classification is based on the assumption that for each disorder there are symptom clusters. Symptoms have in common disturbances in sensory and/or motor gastrointestinal function, which sometimes may overlap across anatomic regions. Nevertheless, several studies provide evidence for site-specific syndromes.

Colonic Diseases, Functional↗
PubMed2000

Inhibition of IgG1 and IgE production by stimulation of the B cell CTLA-4 receptor.

Although a large amount of information is available on the activity of CTLA-4 in T cells, the role of this receptor in B cells has not been previously characterized. Our results show that CD40 or LPS stimulation in the presence of IL-4 induces CTLA-4 expression in purified B cells; the maximum level is reached in both membrane and intracellular compartments after 48-72 h. Engagement of the B cell CTLA-4 by immobilized mAb inhibits IgG1 and IgE production and reduces the frequency of IgG1- and IgE-expressing B cells. Cepsilon and Cgamma(1) germline mRNA expression as well as NF-kappaB and STAT6 activation, events required for isotype switching, are also inhibited by CTLA-4 engagement. Together these findings show the critical role of CTLA-4 in the control of IL-4-driven isotype switching and suggest new approaches for modulating immediate-type hypersensitivity responses.

Abatacept↗
PubMed2000

Accurate diagnosis of Helicobacter pylori. Stool tests.

From the limited data available, it seems that the H. pylori stool assay represents a highly accurate diagnostic tool to detect H. pylori infection before and shortly after therapy. As a test that is noninvasive, accurate, simple, and cost-effective, the H. pylori stool assay has the potential to become the preferred diagnostic tool in many different clinical settings from epidemiologic studies to pediatric investigations, from pre-endoscopic screening policies to posttherapy monitoring.

Antigens, Bacterial↗
PubMed2000

Helicobacter pylori seroconversion in asymptomatic blood donors: a five-year follow-up.

Several techniques have been developed to diagnose Helicobacter pylori infection and two noninvasive methods are available: carbon 13-urea breath test (UBT) and serology. Measurement of IgG serum antibodies by enzyme-linked immunosorbent assay (ELISA) is a reliable and inexpensive method for detection of infection. The aim of this study was to assess the seroconversion by different techniques after five to eight years. In 1990, 588 of 1,010 asymptomatic donors were found to be seronegative by ELISA, based on an H. pylori whole-cell suspension lysate (sensitivity and specificity: 92% and 97%). In 1995 serum samples from 418 of 588 seronegative donors were collected and retested using the same antigen. 411 of 418 samples were frankly negative, and 7 donors were found to be seroconverted. This group of seven sera represents the object of the study. They were retested by ELISA and western blotting using a different antigen (NCTC). To standardize our techniques, sera from 43 H. pylori positive and 47 H. pylori negative patients according to culture, histology, urease test, and UBT were used. The cutoff for ELISA-NCTC was 0.53 AI (absorbance index) (mean value + 2 SD), and for western blotting was negativity for CagA or <10 bands (sensitivity and specificity: 95% and 96%; 98% and 81% for ELISA and western blotting respectively). According to the results obtained in 1990 and 1995, seven donors were found to be seroconverted by ELISA using sonicated antigen; in five the seroconversion was confirmed by ELISA using NCTC antigen and in two there was concordance with WB. Four of the seven donors were contacted and asked to undergo UBT and a further serum sample was drawn to be reassessed in 1998. A seroconversion was found in all four donors by ELISA, while WB and UBT confirmed the seroconversion in only three of four donors. In conclusion the in-house ELISA used performed well compared to other theoretically better serologic assays and confirmed the low seroconversion rate for H. pylori infection in adult populations living in developed countries.

Adult↗
PubMed2000

Isotope ratio mass spectrometry (IRMS) versus laser-assisted ratio analyzer (LARA): a comparative study using two doses of.

This study was carried out to compare the measurements and the diagnostic accuracy of the traditional expensive IRMS and the new economical LARA system using two doses of [13C]urea + two different test meals in patients undergoing upper gastrointestinal endoscopy, both before and after anti-Helicobacter treatment. A total of 354 dyspeptic patients underwent endoscopy with gastric biopsies to diagnose H. pylori infection by CLO-test and histology. No patients had taken antibiotics, bismuth, or antisecretory drugs in the 4 weeks before testing. After overnight fasting, breath samples were collected simultaneously in both plastic and glass tubes at baseline and at 30 and 60 min after urea ingestion. In 237 patients 100 mg [13C]urea + Ensure and in 117 patients 75 mg [13C]urea + citric acid were given. The test was also performed with the two urea dosages and meals in 67 and 64 infected patients, respectively, four weeks after anti-Helicobacter therapy. H. pylori was considered eradicated when both biopsy-based tests were negative. A delta value >5 per thousand was considered positive. Breath samples with insufficient CO2 levels at both 30 and 60 min were excluded from final analysis (N = 37 in pre- and N = 8 in posttreatment). There was excellent agreement between overall delta values of the two machines with both [13C]urea 100 mg + Ensure and [13C]urea 75 mg + citric acid. The 95% CI of the difference against the mean was wider with the former (mean -1.3, +6.3, and -9.4) than with the latter urea dosage and test meal (mean -1.2, +5.2 and -8.1). LARA and IRMS were equally effective (P = NS) in distinguishing infected from uninfected patients before therapy using both doses of [13C]urea and test meals (sensitivity ranged from 95% to 99% and specificity from 95% to 97%). This good performance was maintained in the posttreatment phase (sensitivity ranged from 90% to 100% and specificity from 90% to 97%), without any statistical difference among the various combinations (P = NS). The LARA system is a valid alternative to IRMS in the diagnosis of H. pylori infection. Both machines provide highly reliable results after 30 min, so that the 60 min sample can be avoided. The dose of 75 mg + citric acid suffices to ensure an accurate UBT. The test performed with both devices and [13C]urea dosages is very effective also for posttherapy evaluation of H. pylori status.

Adult↗
PubMed2000

Review article:invasive and non-invasive tests for Helicobacter pylori infection.

There are two general ways in which a diagnosis of infection by Helicobacter pylori can be made: by using either an invasive or non-invasive procedure. The invasive procedures involve an endoscopy and biopsy. A biopsy is essential because often the mucosa may appear macroscopically normal but nevertheless be inflamed. A biopsy is obtained by histological examination, culture, polymerase chain reaction or detection of the presence of urease activity in biopsy material. The non-invasive tests that can be used to diagnose the infection are serology, detection of labelled metabolic products of urea hydrolysis in the breath (13CO2, 14CO2), the urine or the blood, and detection of H, pylori antigen in a stool specimen. At present no single test can be relied upon to detect definitely colonization by H. pylori, and a combination of two is recommended if this is feasible. The choice of the test to be used is not straightforward and may vary according to the clinical condition and local expertise.

Breath Tests↗
PubMed1999

Cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibits CD28-induced IkappaBalpha degradation and RelA activation.

Purified CD4+ cells from the spleens of C57BL/6 mice were stimulated with anti-CD3, anti-CD28 and anti-cytotoxic T lymphocyte antigen (CTLA)-4 monoclonal antibodies. The results show that CTLA-4 stimulation inhibits IL-2 production induced by CD3-CD28 co-stimulation. Since CD3-CD28 co-stimulation induces IkappaBalpha degradation and consequently activates RelA, an NFkappaB family member relevant for the induction of IL-2 mRNA transcription, we tested whether the inhibitory effect of CTLA-4 stimulation interferes with this mechanism. CD3-CD28 co-stimulation was found to induce a drastic decrease in cytoplasmic IkappaBalpha and increase in nuclear RelA. CTLA-4 stimulation abrogates this effect of co-stimulation by increasing the level of cytoplasmic IkappaBalpha and decreasing the nuclear RelA level and DNA-binding activity. In conclusion, our results indicate that the inhibitory effect of CTLA-4 engagement on cytokine production correlates with prevention of IkappaBalpha degradation and inhibition of RelA nuclear translocation.

Abatacept↗