Caracterización espacial de la ganadería bovina en la Orinoquia colombiana / Spatial characterization of the bovine livestock in the Colombian Orinoquia

RESUMEN Objetivo. Utilizar los sistemas de información geográfica (SIG) como herramienta complementaria para caracterizar la ganadería bovina realizada en la región de la Orinoquia. Materiales y métodos. A través del uso de tecnologías espaciales se recopiló la información concerniente a la orientación ganadera, fisiografía, cobertura vegetal y catastro de la zona de estudio para su posterior análisis a través del software ACCESS de Microsoft. Resultados. En un alto porcentaje de los predios ganaderos ubicados en los cuatro departamentos de la Orinoquía (Casanare:72.7%, Meta:49.5%, Arauca:42% y Vichada:32%) predominan las coberturas de pastos, herbazales y vegetación secundaria, confirmando la expansión en la frontera agropecuaria que es promovida por la actividad ganadera en el país. Conclusiones. El uso de los SIG, permite realizar una mejor planificación y distribución eficiente de los recursos destinados a mejorar el funcionamiento de los sistemas de producción. Por ejemplo, en zonas donde la matriz de coberturas predominante son los pastizales y herbazales, las estrategias en pro de la sostenibilidad pueden enfocarse en la implementación de sistemas silvopastoriles, contrario a lo que pasaría en zonas donde la matriz de coberturas tenga un alto porcentaje de bosques naturales.

ABSTRACT Objective. Use Geographic Information Systems (GIS) as a complementary tool to characterize cattle farming in the Orinoquia region. Materials and methods. Through the use of space technologys, information concerning the livestock orientation, physiography, vegetation cover and land registry of the study zone was collected for further analysis over Microsoft ACCESS software. Results. In a high percentage of the cattle ranches located in the four departments (Casanare: 72.7%, Meta: 49.5%, Arauca: 42% and Vichada: 32%) the cover of pastures, grasslands and secondary vegetation predominates, confirming the expansion in the agricultural border that has had the cattle activity in the country. Conclusions. The use of complementary tools such as GIS allows for better planning and efficient distribution of resources to improve the functioning of production systems, for example, in zones where the predominant coverage matrix is grasslands, strategies in pro of sustainability can focus on the implementation of silvopastoral systems, contrary to what would happen in areas where the matrix has a high percentage of natural forests.

[URISCAM project: Multicenter evaluation of the UF-Series cytometer in the urinary tract infections screening]. / Proyecto URISCAM: Evaluación multicéntrica del citómetro UF-Series en el despistaje de infecciones urinarias.

OBJECTIVE: Urine culture, the gold standard to confirm the presence of urinary tract infection (UTI), is the most requested assay in the microbiology department. Our objective was to determine the diagnostic yield of the UF-Series cytometer as a screening method for UTI. METHODS: All the urine samples sent to the six Microbiology Laboratories participating in a period of 5 working days were analyzed. We collected demographic variables, apart from those variables related to urine samples: source and sample type (midstream, catheterized or nephrostomy urines), collection with/without boric acid, cytometer parameters (leukocyturia, bacteriuria, bacteria morphology and epithelial cells) and urine culture results. ROC curves were plotted to determine predictive capacity of the cytometer. RESULTS: A sample of 2,468 patients with average age of 53 years were processed (ratio women:men 2:1). Urine culture detected 23% of positive urine samples. The predictor variables of UTI were: morphology of bacilli, bacteriuria ≥21 bacteria/µL, age ≥65 years, samples collected in the emergency service and hospitalization and preserving conditions. With 21 bacteria/µL as a cut-off point, we obtained a sensitivity of 93.3% and 94.5% negative predictive value, then reducing the samples to be cultured by 28.9% with 1.6% false negatives. CONCLUSIONS: We consider that the UF-Series is a valid and accurate tool for the detection of UTI. Therefore, it could be used as screening method in the clinical practice prior to the urine culture, reducing culture requirement by approximately 30%, with a low false negative rate.

Sysmex UF-1000i flow cytometer to screen urinary tract infections: the URISCAM multicentre study.

The new Sysmex UF-1000i analyzer - which incorporates bacteria morphology distinction - allows to automatically screen samples to be cultured at microbiology laboratories. We have evaluated the feasibility and accuracy of Sysmex UF-1000i to screen urinary tract infections (UTIs). A total amount of 2468 urine samples from six Spanish hospitals were analysed. Demographic and clinical data such as age, gender, source and sample type, preserving conditions, cytometer parameters (bacteria, leucocytes and bacteria morphology) as well as urine culture results (gold standard) were recorded. After applying data mining techniques, the variables of age, bacteria count and rod morphology were defined as predictive variables of UTIs. By using the UF-1000i in combination with a predictive algorithm of three decision rules, we could identify 94·9 and 47·4% positive and negative urine samples, respectively, with a negative predictive value of 97 and only 1·17% diagnostic error. This error was reduced down to 0·4% when contaminated samples were excluded. Our results show that flow cytometry parameters together with age, by means of a predictive algorithm model, can be used to screen UTIs. Its implementation would avoid culturing 38% of urine samples, and therefore, would reduce time to diagnosis with a discrete false negative ratio. SIGNIFICANCE AND IMPACT OF THE STUDY: Fluorescent flow cytometry performance has recently spread for urine screening. However, controversy about cytometer results can be drawn from medical literature. This study shows the diagnosis accuracy of Sysmex UF-1000i analyzer by means of a group of decision rules encompassing both demographic variables (age) and cytometer parameters (bacteria, leucocytes and bacteria morphology). After applying the predictive algorithm, the UF-1000i could optimally identify 95% urinary tract infections with high negative predictive value and low diagnostic error. Implementation of UF-1000i would avoid culturing almost 38% of urine samples, thus reducing time to diagnosis, unnecessary antibiotic treatments and consequently improving cost-effectiveness.

Comparison between a lyse-and-then-wash method and a lyse-non-wash technique for the enumeration of CD34+ hematopoietic progenitor cells.

The flow cytometric enumeration of CD34+ hemopoietic precursor cells (HPC) present in samples used for transplantation of HPC has proven to be the most powerful single parameter for prediction of engraftment. At present, several different methodological approaches are used for the flow cytometric enumeration of CD34+ HPC. In the present study we have compared two of these methods as regards enumeration of CD34+ HPC and their CD34+/CD19- and CD34+/CD19+ subsets: a lyse-non-wash procedure based on the use of a recently commercialized red cell lysing solution (Quicklysis, Cytognos, Salamanca, Spain) and a lyse-and-then-wash method in which the Becton Dickinson (San Jose, CA) FACS Lysing Solution was used. For that purpose a total of 52 samples corresponding to 20 G-CSF mobilized peripheral blood (PB) samples and 21 PB-derived leucapheresis products from patients undergoing autologous PB stem cell harvest, together with 11 bone marrow (BM) samples from healthy volunteers were analyzed. Our results show that for each of the three types of samples analyzed the use of the lyse-and-then-wash method is associated with significantly lower numbers of both total CD34+ HPC (P < or = 0.003) and its major CD34+/CD19- subset (P < or = 0.01) while no significant changes are detected in the number of CD34+/CD19+ HPC in BM samples (P > 0.05). The use of an internal standard (reference beads) added just prior to data acquisition, showed that the differences between both methods are due to a selective loss of CD34+ HPC and its major CD34+/CD19- subset in BM (P=0.002 and P=0.003), PB (P < 0.0001 and P < 0.0001) and PB-derived leucapheresis products (P < 0.0001 and P=0.0001). Finally, addition of a centrifugation and washing step to a group of 11 leucapheresis samples lysed with Quicklysis showed that they did not significantly affect the overall number of total CD34+, CD34+/CD19- and CD34+/CD19+ HPC obtained. In line with these findings elimination of centrifugation and washing steps when FACS Lysing Solution was used to lyse mature red cells almost corrected for the selective loss of CD34+ HPC. In spite of these differences a significant degree of correlation (r > 0.83 in all cases) was found between both methods regarding the total number of CD34+, CD34+/CD19- and CD34+/CD19+ HPC present in the BM, PB and PB-derived leucapheresis samples analyzed in this study.

Comparative kinetic study of lipases A and B from Candida rugosa in the hydrolysis of lipid p-nitrophenyl esters in mixed micelles with Triton X-100.

(1) Lipases A and B from Candida rugosa catalyzing the hydrolysis of esters in micellar media have been characterized kinetically by studies on substrate specificity, rate equation forms and modeling of enzyme mechanisms. (2) The study on specificity revealed that both lipases are non-specific esterases with similar activity against lipid p-nitrophenyl esters micellized with Triton X-100. The slight difference was that lipase A has its maximum activity centered in the caprylate while that of lipase B is in the laurate. (3) Kinetic studies for both lipases were carried out with p-nitrophenyl laurate under three experimental conditions: (I) the molar fraction of substrate is fixed and the bulk concentration of substrate and Triton X-100 are varied; (II) the bulk concentration of substrate is held constant and the molar fraction of substrate and bulk concentration of Triton X-100 are varied; and (III) the bulk concentration of Triton X-100 is held constant but the bulk concentration of substrate and molar fraction of substrate are varied. (4) In case I, a similar Michaelis-Menten behaviour was observed with both lipases; the curve fitting gave kappcat/Kappm values of 3.0.10(5) and 5.6.10(5) s-1 M-1 for lipases A and B respectively. In case II, for both lipases the relationship between rate and the molar fraction of substrate required a fitting equation of 2:2 degree polynomial quotient. In case III, both lipases showed non-Michaelian behaviour with concave-up curves in the Eadie-Hofstee plot, a minimum degree of 2:2 in substrate concentration being detected for the rate equation. (5) The above results are interpreted in terms of the hypothesis that the mechanism of both lipases must include at least two different inputs for the molecule of substrate which would explain the quadratic terms observed in the rate equation.