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T Estrada-Garcia

Publications and source records attributed to T Estrada-Garcia.

5 recordsLinked to original sources
PubMed2004

Prevalence of Escherichia coli and Salmonella spp. in street-vended food of open markets (tianguis) and general hygienic and trading practices in Mexico City.

Street-vendors in Mexico City provide ready-to-eat food to a high proportion of the inhabitants. Nevertheless, their microbiological status, general hygienic and trading practices are not well known. During spring and summer 2000, five tianguis (open markets) were visited and 48 vendors in 48 stalls interviewed. A total of 103 taco dressings were sampled for E. coli and Salmonella spp.: 44 (43%) contained E. coli and 5 (5%) Salmonella (2 S. Enteritidis phage type 8, 1 S. Agona, 2 S. B group). Both E. coli and salmonellas were isolated from three samples. Of Salmonella-positive stalls 80% (4/5) had three or more food-vendors and 80% of vendors were males, compared with 37.3% (16/43) and 46.4% (20/43) in the Salmonella-negative stalls respectively. Food-vendors kept water in buckets (reusing it all day), lacked toilet facilities, and prepared taco dressings the day before which remained at the tianguis without protection for 7.8 h on average. Consumption of street-vended food by local and tourist populations poses a health risk.

Cities↗
PubMed2002

Faecal contamination and enterotoxigenic Escherichia coli in street-vended chili sauces in Mexico and its public health relevance.

The street-vended food industry provides employment and cheap ready-to-eat meals to a large proportion of the population in developing countries like Mexico, yet little is known about its role in the transmission of food borne diseases (FBD). Because of its wide consumption, street-vended chili sauces in Mexico are potential vehicles of FBD. An observational study was performed in Mexico City collecting 43 street-vended chili sauces. These sauces were prepared under poor hygienic conditions of handling and selling. Consumers add 4-8 ml of chili sauce per taco, ingest 2-5 tacos per meal and on average, 50 consumers frequent a stall per day. Seventeen (40%) samples were faecally contaminated and 2(5%) sauces harboured sufficient enterotoxigenic Escherichia coli to cause disease. Weestimate that the consumption of only one of these chili sauces could result in ETEC disease inat least 21,000 consumers per year, making them important potential vehicles of FBD.

Escherichia coli↗
PubMed1993

A fluorescence-based quantitative adhesion assay to study interactions between Entamoeba histolytica and human enterocytes. Effect of proinflammatory cytokines.

In order to study the initial events during infection of target cells by the enteric pathogen Entamoeba histolytica, we developed a quantitative adhesion assay based on the use of a human colonic cell line (CaCo-2) and biotinylated amoebae tagged with fluorescein. To prevent the strong and rapid lytic activity of Entamoeba histolytica on colonic cells, which would otherwise impede the study of the primary adhesion steps, parasites were mildly fixed, biotinylated and labelled with streptavidin-FITC. After labelled parasites have bound to enterocytes, nonadhered amoebae are removed by washing and attached parasites quantified by means of an automated fluorescence plate reader. The bioassay is simple, nonhazardous and can be completed in 1.5 h. We were able to detect ranges from 200 to 20,000 fluorescent parasites per microwell in a 96-well plate, containing approximately 10(5) colonic cells. Fluorescence intensity (arbitrary units) increased in direct relationship to the number of parasites added per well, and was not limited by the size of the culture plate (96, 24 or six wells). As an example of the value of this assay, two proinflammatory cytokines (interleukin-1, (IL-1 beta) and interferon-gamma (IFN-gamma) known to influence the adhesion properties of endothelial and epithelial cells, were used to assess their effects upon enterocyte-entamoeba binding. The increase in amoebae binding revealed by cytokine treatment to enterocytes suggests that the parasite may take advantage of inflammatory stimuli in order to increase its binding to colonic epithelium. We believe this rapid, sensitive and simple method offers the potential for large scale screening assays to study the immunobiology of this protozoal infection by analysing the mechanisms involved in the primary interactions between Entamoeba histolytica and enterocytes.

Animals↗
PubMed1991

A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane.

The localization of the human erythrocyte membrane Ins(1,3,4,5)P4 3-phosphatase was investigated by saponin permeabilization of resealed 'isoionic' erythrocyte ghosts. This enzyme is active at the inner face of the plasma membrane, at the same site as a specific 5-phosphatase that degrades both Ins (1,4,5)P3 and Ins(1,3,4,5)P4. In the presence of EDTA, Ins(1,4,5)P3 was the only product of Ins(1,3,4,5)P4 metabolism. However, when Mg2+ was present both the 5-phosphatase and the 3-phosphatase attacked Ins (1,3,4,5)P4, directly forming Ins(1,3,4)P3 and Ins(1,4,5)P3;some Ins(1,4)P2 was also formed as a product of 5-phosphatase attack on the liberated Ins(1,4,5)P3. The Ins(1,3,4,5)P4 3-phosphatase was potently activated by KCl, thus making the route of metabolism of Ins(1,3,4,5)P4 by erythrocyte ghosts strikingly sensitive to variations in ionic strength: at 'cytosolic' K+ and Mg2+ levels, 3-phosphatase activity slightly predominated over 5-phosphatase. Ins(1,3,4,5)P4 3-phosphatase was potently inhibited by Ins-(1,3,4,5,6)P5 and InsP6 at levels lower than those often observed within cells. This leaves open the question as to whether the cellular function of inositol polyphosphate 3-phosphatase is to participate in a physiological cycle that interconverts Ins(1,3,4,5)P4 and Ins(1,4,5)P3 or to metabolize other inositol polyphosphates in the cytosol compartment of cells.

Erythrocyte Membrane↗