Aim: To devise a follow up model for patients with gastric cancer associated lesions, such as atrophic chronic gastritis (ACG) and intestinal metaplasia (IM). Methods: Cohort study of 144 patients, followed for a minimum of one year, in whom at least two upper gastrointestinal endoscopic biopsies in flat gastric mucosa provided a diagnosis of ACG, IM, or low grade dysplasia (LGD). Results: Of those diagnosed with ACG at first endoscopic biopsy (entry biopsy), 12% progressed to LGD in outcome biopsy, as did 8% of those with type I IM, 38% with type II or III IM, and 32% with LGD. Type of IM at entry independently predicted progression to LGD and cancer. Type II and III IM had a higher rate of progression to LGD than type I IM, which showed an indolent behaviour similar to ACG. Patients with type II or III IM were at higher risk for development of dysplasia, and 7% of patients with type III IM at first biopsy progressed to high grade dysplasia (HGD), whereas no cases of ACG or type I/II IM progressed to HGD during the first three years. Conclusion: Patients with ACG or IM could possibly be allocated to different management schedules, based on differences in rate and proportion of progression to LGD or HGD. Less intensive follow up (two/ three yearly with ''serological evaluation'' (pepsinogen)) may suit those with ACG or type I IM. Patients with type III IM may benefit from six to 12 monthly improved endoscopic examination (magnification chromoendoscopy).

A cohort of individuals (n = 136) with lesions as severe as atrophic chronic gastritis (ACG) was cross-sectionally evaluated for the validity assessment of pepsinogen I (PGI) and pepsinogen II (PGII) serum levels for the diagnosis of intestinal metaplasia (IM) and gastric dysplasia. PGI/PGII ratio [median (range)] was 4 (0.5-7.5) in patients with ACG (n = 35); 4.6 (1.9-6.8) in type I IM (n = 18); 4.2 (1.4-5.9) in type II or type III IM limited to the antrum and incisura (n = 20); 2.4 (0.4-5.6) in extensive incomplete IM (n = 38); and 1.3 (0.4-6.4) in low-grade dysplasia (n = 23) (P = .002). Using histopathologic data as a reference test, the area under the receiver operating characteristic curves (CI 95%) was 0.73 (0.64-0.82) for extensive IM, 0.72 (0.58-0.85) for the diagnosis of dysplasia, and 0.81 (0.66-0.95) for the diagnosis of high-grade dysplasia. Using a PGI/PGII ratio of < or =3 as the cutoff for dysplasia diagnosis, the sensitivity was 70% (62-78%), the specificity was 65% (57-73%), and the negative predictive value estimates were over 90%. No differences in PG levels according to age or gender were observed. Helicobacter pylori did not significantly influence validity measurement estimates. PGI/PGII serum level ratio can be used even in the management of patients with a high a priori probability for a positive test. It may be useful for the exclusion of more advanced lesions (extensive IM and neoplastic lesions).

Cryptosporidium parvum is transmitted through water and can cause severe diarrhea. The diagnosis is usually based upon observer-dependent microscopic detection of oocysts, with rather low sensitivity and specificity. Our objective was to optimize a flow cytometric (FC) protocol for the detection of C. parvum. A specific monoclonal antibody conjugated with R-phycoerythrin was incubated with dead oocysts to determine the optimal antibody concentration. Serial concentrations of oocysts were stained with the optimized concentration and analyzed by FC. The lower detection limit was determined, and the possibility of cross-reaction was investigated using prokaryotic and eukaryotic microorganisms. A FC protocol was optimized to detect oocysts in spiked human stools. The optimal antibody concentration was found to be 3.0 mg/ml. The lowest number detectable was 2 × 10 3 oocysts/ml. Staining procedure was specific, as no cross-reactions were observed. This reliable and easy FC protocol allow the specific detection of Cryptosporidium oocysts, even at very low concentrations, which is important for public health and further studies of treatment efficacy. ' 2007 International Society for Analytical Cytology

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Encephalitozoon intestinalis is responsible for intestinal disease in patients with AIDS and immunocompetent patients. The infectious form is a small spore that is resistant to water treatment procedures. Its detection is very important, but detection is very cumbersome and time-consuming. Our main objective was to develop and optimize a specific flow cytometric (FC) protocol for the detection of E. intestinalis in hospital tap water and human feces. To determine the optimal specific antibody (Microspor-FA) concentration, a known concentration of E. intestinalis spores (Waterborne, Inc.) was suspended in hospital tap water and stool specimens with different concentrations of Microspor-FA, and the tap water and stool specimens were incubated under different conditions. The sensitivity limit and specificity were also evaluated. To study spore infectivity, double staining with propidium iodide (PI) and Microspor-FA was undertaken. Distinct approaches for filtration and centrifugation of the stool specimens were used. E. intestinalis spores stained with 10 g/ml of Microspor-FA at 25°C overnight provided the best results. The detection limit was 5 ؋ 10 4 spores/ml, and good specificity was demonstrated. Simultaneous staining with Microspor-FA and PI ensured that the E. intestinalis spores were dead and therefore noninfectious. With the stool specimens, better spore recovery was observed with a saturated solution of NaCl and centrifugation at 1,500 ؋ g for 15 min. A new approach for the detection of E. intestinalis from tap water or human feces that ensures that the spores are not viable is now available and represents an important step for the prevention of this threat to public health.