Apparent Bicarbonate Space in Children

The amount needed to change the concentration of a solute requires the knowledge of its volume of distribution in the solution. Electrolytes that do not participate in active metabolic reactions have a fixed volume of distribution that corresponds to the volume of water in which they solubilize. Bicarbonate infusion is used to correct hyperchloremic metabolic acidosis. Its volume of distribution (bicarbonate space) changes with its participation in the blood buffer systems. In other words, it is not a fixed physical volume, like that of other solutes. In this paper, we shall review experimental studies that supported evidence for this knowledge and analyze the basic hypothesis to explain the phenomena. Since we have not found clinical studies in children, we shall report our experience in a group of patients with metabolic acidosis treated with bicarbonate infusion in whom apparent bicarbonate space was measured and compared with data in adults from the literature. Guidelines for amount of bicarbonate needed to increase its concentration according to baseline bicarbonate concentration will be suggested

MODERNIZATION OF THE TRADING AND LOGISTIC SYSTEM OF THE FRUIT AND VEGETABLE SECTOR OF CHUBUT PROVINCE, PATAGONIA

The Valle Inferior del Río Chubut (VIRCH) is the main valley irrigated of Patagonia –Argentina- with 23,000 hectares (69,000 acres) where, after livestock, the vegetable and fruit production has gained second place in importance because of its localization underneath the Barrier of Animal and Plant Health of Rio Colorado, which makes the products safer since it is used much less agrochemicals, and consequently offers higher quality and less perishable, although the valley production do not cover local consumption. Because of that, the Provincial Government with the National Government’s technical support created a Program denominated "Development and Strengthening of an Agrifood Platform for fruit and vegetable in Chubut Province", counting with local and international financing. This proposal tries to ensure the provision or supply of fruits and vegetables to local consumers for which requires infrastructure and adequate tools to improve transparency of commercial transactions. In the meantime, to transforming the system of wholesale marketing it is required the construction of a platform as a place of development of new services companies and improvement the current ones. This Unit will be a right marketplace for buying wholesale horticultural products coming from other markets outside the region and for stimulates consumption through the implementation of food safety and quality control among other advantages such as fair prices. The main purpose is to analyze modernization of the Trading System and Logistics for fruits and vegetables of the province of Chubut

A glucosylceramide synthase inhibitor prevents the cytotoxic effects of Shiga toxin-2 on human renal tubular epithelial cells

Shiga toxin-2 binds to the globotriaosyl-ceramide receptor on the plasma membrane of target cells. The highlevel expression of this receptor in renal epithelial cells may account, at least in part, for acute renal failure observed inchildren with hemolytic uremic syndrome. The cytotoxic effect of Shiga toxin-2 was assayed on primary cultures of humanrenal tubular epithelial cells treated with a new specific inhibitor of glucosylceramide synthase (C-9), the ratelimitingfirst step in the glycosphingolipid biosynthetic pathway. The treatment of the cells with 1-5 M C-9 for at least24 h significantly neutralized the action of 1 ng/ml Shiga toxin-2 on cell viability. The expression levels of globotriaosylceramidesignificantly decreased when cells were incubated with 1 M C-9 for 48 h. We propose here that prevention ofglobotriaosyl-ceramide synthesis by the C-9 could be a novel substrate inhibition therapy to neutralize Shiga toxin-2 actionin renal epithelial cells.Fil: Silberstein, Claudia Marcela. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Copeland, Diane P. No especifíca;Fil: Chiang, Wei Lien. No especifíca;Fil: Repetto, Horacio A.. Hospital Nacional Profesor Alejandro Posadas; ArgentinaFil: Ibarra, Cristina Adriana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Epidemiology of Argentinean Shiga Toxin-Producing Escherichia coli

Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen that can cause nonbloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). HUS, a life-threatening complication that occurs in 5-10% of patients, is characterized by hemolytic anemia, thrombocytopenia, and renal failure. ...Fil: Rivas, Marta. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Chinen, Isabel. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Miliwebsky, Elizabeth. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; ArgentinaFil: Galli, Lucía. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorio e Instituto de Salud ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Repetto, Horacio A.. Hospital Nacional Profesor Alejandro Posadas; ArgentinaFil: Masana, Marcelo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Agroindustria. Instituto de Tecnología de Alimentos; Argentin

Development of an experimental hemolytic uremic syndrome in rats

Escherichia coli strains producing Shiga toxins (Stxs) colonize the lower gastrointestinal tract and cause watery diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome (HUS). HUS is characterized by hemolytic anemia, thrombocytopenia, and acute renal failure. Oliguria associated with acute tubular necrosis and microangiopathic thrombosis has been reported as the most common cause of renal failure in Argentinean children. Our study was undertaken to obtain a model of HUS in rats that was similar to the clinical and renal histopathology findings described in humans. Rats were intraperitoneally inoculated with culture supernatant from recombinant E. coli expressing Stx2. Glomerular filtrate volume evaluated from clearance of creatinine resulted in a progressive reduction (from 53% at 24 h to 90% at 48 h). Urine volume increased significantly at 24 h but returned to normal levels at 48 h. Evidence of thrombocytopenia, anemia and leukocytosis was documented. Macroscopic analysis revealed a hyperemic peritoneal face with intestinal water accumulation. The kidneys were friable and congestive. Histopathological analysis showed glomerular and tubular necrosis as well as microangiopathic thrombosis. Our findings indicated vascular damage and kidney lesions similar to those described in humans with HUS.Fil: Zotta, Elsa. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Lago, Néstor Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Patología; ArgentinaFil: Ochoa, Federico Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; ArgentinaFil: Repetto, Horacio A.. Hospital Nacional Profesor Alejandro Posadas; ArgentinaFil: Ibarra, Cristina Adriana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Action of shiga toxin type-2 and subtilase cytotoxin on human microvascular endothelial cells.

The hemolytic uremic syndrome (HUS) associated with diarrhea is a complication of Shiga toxin (Stx)-producing Escherichia coli (STEC) infection. In Argentina, HUS is endemic and responsible for acute and chronic renal failure in children younger than 5 years old. The human kidney is the most affected organ due to the presence of very Stx-sensitive cells, such as microvascular endothelial cells. Recently, Subtilase cytotoxin (SubAB) was proposed as a new toxin that may contribute to HUS pathogenesis, although its action on human glomerular endothelial cells (HGEC) has not been described yet. In this study, we compared the effects of SubAB with those caused by Stx2 on primary cultures of HGEC isolated from fragments of human pediatric renal cortex. HGEC were characterized as endothelial since they expressed von Willebrand factor (VWF) and platelet/endothelial cell adhesion molecule 1 (PECAM-1). HGEC also expressed the globotriaosylceramide (Gb3) receptor for Stx2. Both, Stx2 and SubAB induced swelling and detachment of HGEC and the consequent decrease in cell viability in a time-dependent manner. Preincubation of HGEC with C-9 -a competitive inhibitor of Gb3 synthesis-protected HGEC from Stx2 but not from SubAB cytotoxic effects. Stx2 increased apoptosis in a time-dependent manner while SubAB increased apoptosis at 4 and 6 h but decreased at 24 h. The apoptosis induced by SubAB relative to Stx2 was higher at 4 and 6 h, but lower at 24 h. Furthermore, necrosis caused by Stx2 was significantly higher than that induced by SubAB at all the time points evaluated. Our data provide evidence for the first time how SubAB could cooperate with the development of endothelial damage characteristic of HUS pathogenesis

Effects of Escherichia coli subtilase cytotoxin and Shiga toxin 2 on primary cultures of human renal tubular epithelial cells.

Shiga toxin (Stx)-producing Escherichia coli (STEC) cause post-diarrhea Hemolytic Uremic Syndrome (HUS), which is the most common cause of acute renal failure in children in many parts of the world. Several non-O157 STEC strains also produce Subtilase cytotoxin (SubAB) that may contribute to HUS pathogenesis. The aim of the present work was to examine the cytotoxic effects of SubAB on primary cultures of human cortical renal tubular epithelial cells (HRTEC) and compare its effects with those produced by Shiga toxin type 2 (Stx2), in order to evaluate their contribution to renal injury in HUS. For this purpose, cell viability, proliferation rate, and apoptosis were assayed on HRTEC incubated with SubAB and/or Stx2 toxins. SubAB significantly reduced cell viability and cell proliferation rate, as well as stimulating cell apoptosis in HRTEC cultures in a time dependent manner. However, HRTEC cultures were significantly more sensitive to the cytotoxic effects of Stx2 than those produced by SubAB. No synergism was observed when HRTEC were co-incubated with both SubAB and Stx2. When HRTEC were incubated with the inactive SubAA272B toxin, results were similar to those in untreated control cells. Similar stimulation of apoptosis was observed in Vero cells incubated with SubAB or/and Stx2, compared to HRTEC. In conclusion, primary cultures of HRTEC are significantly sensitive to the cytotoxic effects of SubAB, although, in a lesser extent compared to Stx2