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O Doiz

Publications and source records attributed to O Doiz.

8 recordsLinked to original sources
PubMed2002

Helicobacter pylori stimulates pepsinogen secretion from isolated human peptic cells.

BACKGROUND: Different acid and peptic related gastroduodenal diseases are associated with both increased gastric secretion and Helicobacter pylori infection. Patients with H pylori associated gastritis or duodenal ulcer have increased serum pepsinogen levels which decrease after eradication. The mechanisms of H pylori induced gastric mucosal damage are not completely understood. AIM: To determine the effects of H pylori on pepsinogen secretion from isolated human peptic cells. METHODS: Dispersed human peptic cells were prepared from endoscopically obtained biopsy specimens after collagenase digestion, mechanical disruption, and density gradient centrifugation. H pylori was obtained from gastric biopsies (antrum and body), and cultured in non-selective and selective media. Isolates of H pylori were used at different concentrations (1 - 20 x 10(6) colony forming units (cfu)). RESULTS: H pylori (10(6) - 2 x 10(7) cfu) increased basal pepsinogen secretion in a concentration dependent manner. This stimulus was not observed with Escherichia coli. The increased secretion was in addition to that observed with 0.1 mM histamine and 0.1 mM dibutyryl-cyclic adenosine monophosphate. However, H pylori did not affect either carbamylcholine (0.1-10 microM) or cholecystokinin (1 microM) stimulated pepsinogen secretion. Addition of the nitric oxide synthase inhibitor N(w)-monomethyl-L-arginine (1 mM) inhibited H pylori induced cGMP generation and pepsinogen secretion, which were also reduced in the absence of extracellular calcium. H pylori induced pepsinogen secretion was not affected by the absence/presence of the cagA gene. CONCLUSIONS: H pylori increases pepsinogen secretion from human peptic cells through a calcium and nitric oxide mediated intracellular pathway. This effect is independent of the H pylori virulent cagA gene, and may be a mechanism of H pylori induced gastric mucosal damage.

Adult↗
PubMed2001

Western blot applied to the diagnosis and post-treatment monitoring of human hydatidosis.

The serologic diagnosis of hydatidosis (caused by Echinococcus granulosus) can be made by different techniques, although the lack of standardization of the antigens affects the sensitivity, specificity and concordance among the different tests. We have applied the Western-Blot (WB) technique, associated with a purified antigen from sheep hydatid fluid, at 60 samples of serum from 14 patients suffering echinococcosis in different bodily locations, monitored for 3 years. The WB test enabled the detection of antibodies in the pre-surgical samples for proteins of 12-14, 16, 20, 24-26, 34, 39 and 42 kDa in molecular weight in 15-96% of the patients. The combination involving 2 of the 3 proteins of 20, 39 and 42 kDa has made it possible to diagnose 100% of the cases. The antibodies specific to proteins 39 and 42 kDa disappeared in less than one year in the patients cured after surgery, while in patients with persistent or recurrent parasitism the bands present before surgery persisted or other new ones appeared. The WB with purified antigens proved to be highly useful in the diagnosis and post-surgical monitoring of hydatidosis patients. The antigen used is proposed as a standard antigen for the diagnosis and follow-up of pre- and postsurgical hydatidosis.

Adult↗
PubMed1999

Visualization of hydatid elements: comparison of several techniques.

Some techniques available at our laboratory were tested for their ability to aid in the morphological diagnosis of hydatid elements (Echinococcus granulosus ["Taenia echinococcus"]) isolated from cysts in humans and sheep. Unstained, methanol-fixed hooklets were fluorescent, most starkly so under violet light (excitation filter wavelength, 405 nm; long-pass filter wavelength, 495 nm). Auramine-rhodamine and Gram procedures failed to stain hooklets. Ziehl-Neelsen stain yielded indifferent results when organisms were viewed under transmitted light but resulted in a surprisingly intense red fluorescence when organisms were viewed under green light (excitation, 546 nm; long pass, 590 nm). Wheatley trichrome stain gave better and more uniform results than fuchsin. Ryan trichrome blue stain was the best under transmitted light; hooklets stained uniformly and intensely and were easily distinguishable from the background. Very satisfactory results were also obtained with a much simpler procedure (modified Baxby technique: no fixation, steaming hot 1% safranin for 2 min, and malachite green for 30 s). Therefore, Ryan and modified Baxby stains are recommended for the examination of E. granulosus under transmitted light. For fluorescence microscopy, Ziehl-Neelsen stain under green excitation light, or violet light with no staining, is also very useful. Epifluorescence microscopy is especially convenient for examining samples concentrated by filtration, as it renders the filter pores inconspicuous.

Animals↗
PubMed1998

Fuchsin fluorescence and autofluorescence in Cryptosporidium, Isospora and Cyclospora oocysts.

Cryptosporidium parvum and Isospora belli oocysts stained with carbol-fuchsin, as in a modified Ziehl Neelsen technique, fluoresce bright red under green light (546nm). Cryptosporidium oocysts tend to fluoresce more brightly the less intensely stained they appear under transmitted light; this is not the case with Isospora. Fuchsin-stained Cyclospora cayetanensis oocysts fluoresce rather dimly, but those not taking the dye retain their typical autofluorescence. Cryptosporidium and Isospora oocysts are also autofluorescent, appearing violet under u.v. light (365 nm), and green under violet (405 nm) and blue-violet light (436 nm). Their autofluorescence does not survive the staining procedure.

Animals↗