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ResumenLa respuesta de los cultivos a la aplicación de fósforo (P) depende del nivel de disponible (P-Bray) en el suelo. Los objetivos de este trabajo fueron determinar la distribución de la concentración de P-Bray en suelos agrícolas de la región Pampeana y ExtraPampeana argentina mediante la confección de mapas de P-Bray y la comparación de estos con los resultados de un relevamiento realizado en 1980. Otro objetivo fue comparar la eficiencia de predicción (EP) de dos métodos de interpolación: 1) el método inversa de la distancia ponderada (IDP) y 2) el Kriging ordinario (KO). Se trabajó con 34.328 muestras del estrato superficial del suelo (0-20 cm), provenientes de laboratorios privados y oficiales (INTA), extraídas en 2005 y 2006. Ambos métodos de interpolación produjeron mapas similares y valores de EP que oscilaron del 64 al 66%. Los niveles de P-Bray en suelos fueron inferiores o iguales a 15 mg kg-1 en la provincia de Buenos Aires, este de La Pampa, sudeste de Córdoba y sur de Santa Fe (aproximadamente 15.227.000 ha), donde la disponibilidad de P podría limitar la producción de los cultivos en esta área. Por su parte, los suelos con concentraciones mayores a 15 mg kg-1 cuparon el 45% del área (aproximadamente 12.774.000 ha), los que se ubicaron principalmente en la región ExtraPampeana. La disminución de la concentración de P disponible en los últimos 25 años fue más importante hacia el oeste y norte que en el sur de la región Pampeana.AbstractCrop response to applied phosphorus (P) depends on soil available P (P-Bray). The objectives of this work were to determine P-Bray distribution in agricultural soils of the within the pampean and out of the pampean region of Argentina, to map P-Bray oncentration and to compare the current values with those of soil sampling carried out in 1980. Another objective was to compare the prediction efficiency (EP) of two interpolation methods: 1) inverse distance weighting (IDW) and 2) ordinary Kriging method (KO). This work was carried out with 34.328 soil samples of surface layer (0-20 cm), coming from private and official laboratories (INTA), collected in 2005 and 20 6. The interpolation methods produced similar maps and EP values that ranged from 64 to 66%. Soil P-Bray levels were lower or equal to 15 mg kg-1 in the Buenos Aires province, east of La Pampa, southeast of Córdoba and south of Santa Fe (approximately 15.227.000 ha), and therefore, P availability could limit crop production in this area. On the other hand, soils with available P concentrations higher than 15 mg kg-1 occupied 45% of the area (approximately 12.774.000 ha), and these soils were located mainly out of the pampean region. The decrease of available P concentration in the last 25 years was more important in the west and north than in the south of the pampean region.

Background: The presence of cagA antibodies constitutes a serum marker of infection caused by virulent strains of Helicobacter pylori. The objective of this study was to determine the risk of peptic ulcer in patients with H. pylori infection, in relation to the detection of CagA and VacA antibodies., Patients and Method: Prospective case-control study including 104 peptic ulcer patients with active H. pylori infection (positive urease test and/or histology, or positive urea breath test) and 104 age- and sex-matched controls, without peptic ulcer history, with active H. pylori infection (positive urea breath test). Serum CagA and VacA antibodies were determined by Western blot. Non-steroidal antiinflamatory drugs (NSAID) use was determined by structured data collection. A multivariate analysis (logistic regression) was carried out to determine the odds ratio (OR)., Results: Presence of serum antibodies against CagA was higher in peptic ulcer patients (74%) than in controls (46.2%) (OR = 5.7; 95% CI = 2.1-15.6). However, presence of serum antibodies against VacA in patients (46.2%) was similar to that in controls (36.5%). NSAID use was also more frequent in patients (51.9%) than in controls (21,2%) (OR = 6.5; 95% CI = 2.2-19,5)., Conclusions: Serum antibodies against CagA and use of NSAID are the most important risk factors for peptic ulcer disease.

We study in a group of patients with endoscopically diagnosed duodenal ulcer (19; 17 males) and controls (11; 7 males) the gastric emptying of solids through scintigraphy and gastric acid secretion by standard tests. In the same way we investigated prospectively some clinical data, specially smoking habits. As a whole, patients with duodenal ulcer showed an emptying of solids slightly faster than controls (T 1/2-minutes-: 85.4 +/- 28.6 in patients with duodenal ulcer versus 116.9 +/- 46.5 in controls, p less than 0.03). However, most of our patients (15 of 19 or 79%) were found to have a normal emptying rate. No correlation was found between secretory outputs and gastric emptying. Smokers with duodenal ulcer had a faster emptying that non-smokers with duodenal ulcer (T 1/2 74.8 +/- 30.05 vs. 99.91 +/- 19.86; p = 0.05).