Search PubMed⌕ Search

Biomedical subjects

M Quina

Publications and source records attributed to M Quina.

At least 19 recordsLinked to original sources
PubMed2000

Comparison of tests for assessment of Helicobacter pylori eradication: results of a multi-centre study using centralized facility testing.

BACKGROUND: The accuracy of diagnostic tests to assess Helicobacter pylori eradication has rarely been performed. AIM: To compare the tests most commonly used for this purpose, i.e. histology, culture and (13)C urea breath test performed in centralized facilities. METHODS: Prospective study where patients were included in four centres and diagnostic tests performed centrally by biologists experienced in the field. Gastric biopsies were obtained from antrum and corpus (two for histology, two for culture from each site) 4-6 weeks after an eradication treatment. The definition of a gold standard for H. pylori-positive patients was either a positive culture or both positive histology and urea breath test results. RESULTS: Ninety-seven patients for whom data on histology, culture and (13)C urea breath test were available were included. The majority were females (60%) suffering from non-ulcer dyspepsia (52%) and having received proton-pump inhibitor-based triple therapy (62%). Forty-one per cent of the patients were H. pylori-positive according to the gold standard. The sensitivities were 90%, 95% and 92.5% and the specificities 100%, 98.2% and 100% for culture, histology and (13)C urea breath test, respectively. CONCLUSION: All the methods had excellent specificity but the sensitivity ranged between 90 and 95%. The combination of two techniques which increases the sensitivity to virtually 100% is recommended in situations where the eradication treatment requires a precise evaluation such as in clinical trials.

Breath Tests↗
PubMed2000

Noninvasive antigen-based assay for assessing Helicobacter pylori eradication: a European multicenter study. The European Helicobacter pylori HpSA Study Group.

OBJECTIVE: In a recently published multicenter study involving 501 patients undergoing esophagogastroduodenoscopy (EGD) throughout Europe, we showed the high accuracy of a recently developed simple test (HpSA) to detect Helicobacter pylori (H. pylori) antigens in stools of untreated patients. The aim of this study was to assess the diagnostic usefulness of HpSA compared with 13C UBT shortly after H. pylori eradication treatment. METHODS: Of the 501 patients enrolled in the validation study, 279 were found to be H. pylori-positive. These patients were given H. pylori eradicating regimen and asked to return for follow-up EGD with biopsies, 13C UBT and HpSA testing 4 wk after therapy. Follow-up results were available for 235 patients. Of these, 162 consented to all testing and 73 consented only to 13C UBT and HpSA testing. We assessed sensitivity and specificity of both HpSA and 13C UBT compared with biopsy-based methods in the 162 patients, who accepted follow-up EGD. We also assessed sensitivity and specificity of HpSA compared with 13C UBT, arbitrarily chosen as the gold standard, in the whole population of 235 patients. RESULTS: Sensitivity and specificity in 162 patients who consented to a second EGD were 93.8% (CI: 85.4-100%) and 96.9% (CI: 93.9-99.9%) for HpSA, and 90.6% (CI: 80.5-100%) and 99.2% (CI: 97.7-100%) for UBT. Using EGD-based methods as the gold standard, 130 of the 162 treated patients' H. pylori infection were eradicated (125 HpSA-negative, one borderline, and four false-positive; 129 13C UBT-negative, one false-positive), and 32 remained H. pylori-infected (30 HpSA-positive, two false-negative, 29 13C UBT-positive, three false negative). The overall eradication rate was 80.2%. The sensitivity and specificity of HpSA relative to UBT as the gold standard in the overall population (n = 235) were 95.6% (CI: 89.6-100%) and 94.7% (CI: 91.5-97.9%), respectively. CONCLUSIONS: HpSA has proven to be a useful method in posttreatment eradication testing for H. pylori. Its ease of use, speed, and noninvasive nature make HpSA testing an ideal method for post-treatment monitoring where a second EGD may not be justified.

Adult↗
PubMed1999

Diagnosis of Helicobacter pylori infection with a new non-invasive antigen-based assay. HpSA European study group.

BACKGROUND: Helicobacter pylori is a common human pathogen implicated in certain gastrointestinal diseases. In the search for new non-invasive techniques to diagnose H. pylori infection, we evaluated an EIA for H. pylori antigen in stool (HpSA). METHODS: In a prospective multicentre study, stool specimens from 501 patients (276 men, 225 women; age range 17-88 years, mean 52) undergoing gastroscopy in 11 centres throughout Europe were tested with HpSA and the carbon-13-urea breath test. At endoscopy, four biopsy samples were taken for histology (haematoxylin and eosin) and H. pylori detection (giemsa in both antrum and corpus, culture and rapid urease test). Patients were defined as positive for H. pylori if histology (antrum, corpus, or both) and urease test were positive, or if culture was positive. Patients classified as having H. pylori infection received an eradication regimen; 107 were reassessed 4 weeks after therapy. FINDINGS: Of 272 patients with H. pylori infection by the predefined criteria, 256 were positive by HpSA (sensitivity 94.1% [95% CI 90.6-96.6]). Of 219 patients without infection, 201 were negative by HpSA (specificity 91.8% [87.3-95.1]). INTERPRETATION: The stool assay was a reliable and easy-to-use tool for diagnosis of H. pylori infection. The test was accurate even shortly after treatment.

Adolescent↗
PubMed1999

Helicobacter pylori type I strains among Austrian and Portuguese patients with gastritis, peptic ulcer or gastric cancer.

The frequency of occurrence of Helicobacter pylori type I strains in isolates from Austria and Portugal and different polymerase chain reaction-based approaches to detect the cag pathogenicity island were assessed. Of the 41 Austrian strains, eight of 14 (57.2%) isolated from patients with gastritis, 14 of 19 (73.7%) from patients with peptic ulcer and eight of eight (100%) from patients with gastric cancer were type I strains. Among the Portuguese strains, eight of 14 (57.2%) isolated from patients with gastritis, ten of 12 (83.3%) from patients with peptic ulcer and five of 13 (38.5%) from patients with gastric cancer were classified as type I. Thus, Helicobacter pylori type I strains occur frequently in both populations but show no significant correlation with peptic ulcer disease. The prevalence of the type Igenotype in Austrian cancer patients, however, was significantly higher (P=0.007). The cagE-specific polymerase chain reaction was found to be a reliable and efficient method for detection of the cag pathogenicity island.

Adolescent↗
PubMed1996

DNA hypomethylation and proliferative activity are increased in the rectal mucosa of patients with long-standing ulcerative colitis.

BACKGROUND: DNA methylation and DNA cytometric parameters were evaluated in the rectal mucosa from patients with extensive and long-standing ulcerative colitis. METHODS: Twenty-six patients with extensive disease for more than 7 years and 11 healthy controls were included. Global DNA methylation was assessed as the capacity of the DNA test to incorporate [3H]methyl groups from [3H]-S-adenosyl-methionine in the presence of Sss1 methylase. A higher incorporation reflects a lower state of intrinsic methylation. DNA ploidy, S-phase fraction, and proliferative index (PI = S + G2M) of the cell cycle were analyzed by flow cytometry. RESULTS: Incorporation of the [3H]methyl groups into DNA was 10-fold higher in patients compared with controls (P < 0.001) and was significantly higher in patients with histologically active disease (P = 0.02). With regard to flow cytometry, all samples showed a diploid pattern, but S-phase fraction and the proliferative index values were significantly increased in patients compared with controls (P = 0.0007 and P = 0.003, respectively). A positive correlation was found between S-phase fraction and proliferative index and the number of exacerbations of the disease (P < 0.005), and there was a trend among those patients who had disease for longer than 20 years to present with increased cellular proliferation compared with those with a shorter evolution of disease (P > 0.05). CONCLUSIONS: DNA hypomethylation and proliferative activity are increased in this group of patients, supporting the concept that their colonic mucosa undergoes epigenetic and kinetic changes that might predispose these individuals to develop colorectal neoplasms. However, it cannot be ruled out that these markers solely reflect hyperproliferation associated with active inflammation.

Adult↗
PubMed1996

Mutagenic activity of glycine upon nitrosation in the presence of chloride and human gastric juice: a possible role in gastric carcinogenesis.

The mutagenic activity of glycine upon nitrosation was studied in the Ames tester strains TA98, TA100, TA102, and TA104. The results obtained show that glycine at acidic pH values and in the presence of Cl- can react with nitrite giving rise to genotoxic compounds to the tester strains used. When these experiments were carried out in the presence of gastric juice the genotoxicity observed was associated with the Cl- concentration in the different gastric juice samples. The nature and the mechanism of genetic lesion induced by the ultimate genotoxicant arising from the nitrosation of glycine are not fully understood. Primary amines (e.g., amino acids) have been described as potential alkylating agents after nitrosation. However, in our experimental conditions these alkylating activities were not detected, suggesting that other mechanisms could be involved in the genetic lesion induced by nitrosated glycine. The influence of Cl- in the genotoxic activity of glycine and other primary amines upon nitrosation and its possible involvement in the etiology of gastric cancer are discussed.

Chlorides↗
PubMed1995

[Pancreatic tumors. Therapeutic endoscopy of malignant stenoses of the common bile duct using endoprostheses].

From September 1987 to April 1994, 144 biliary endoprostheses were introduced (81 male; 63 female; mean age 68.7 years) in patients presenting distal stricture of the common bile duct by pancreatic tumors. 135 plastic (10 and 12 French) and 9 metallic (30 French) prostheses were placed. The most common complication associated with plastic prostheses is clogging (16%); this problem was solved with the use of metallic prosthesis, which is limited by their high cost. The mortality and morbidity are lower and the time hospital discharge is shorter until, than the ones associated with bilio-digestive anastomosis; mean survival is similar with two procedures endoscopy/surgery.

Aged↗
PubMed1995

[Advances in the endoscopic therapy of chronic pancreatitis].

Endoscopic interventional techniques have created a wide new perspective for non-surgical treatment of chronic pancreatitis (CP). Surgery and endoscopy differ in their techniques, but are comparable with regard to tactics. The aim of methods in CP is to relieve pain and/or local complications. The preliminary results of endoscopic procedures in CP are promising and the methods appear safe in the hands of experienced endoscopists.

Chronic Disease↗
PubMed1993

Schistosomiasis and vascular alterations of the colonic mucosa.

The diagnosis of schistosomiasis is made by identification of Schistosoma in stool and urine, or by colonic or hepatic biopsies. The authors demonstrate in this paper, however, that it is also possible to suspect this disease by colonoscopy, i.e., by macroscopic observation of the vascular alterations in the mucous membrane of parasite infected patients. Out of 33 patients -21 with schistosomiasis and 12 with other intestinal parasitoses--the endoscopist correctly diagnosed Schistosomiasis in 18 (85.7%) patients, although he had no previous experience of the diagnosis. Since this infection is widespread throughout the world, these endoscopic findings are important; they may help the physician correctly diagnosis schistosomiasis in non-endemic areas where the diagnosis may not be suspected.

Adult↗