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Background: The Gyr breed is widely used in Colombian low tropic dairy production systems. During the last 10 years, the Asociación Colombiana de Criadores de Ganado Cebú† - ASOCEBU, has been leading a dairy milk control program which led to the creation of a dataset that permits to carry out the first analysis of milk yield in Gyr cattle in the country using records from several herds. Objectives: To study milk production dynamics of Gyr cattle in the Colombian low tropic through the estimation of lactation curves and four derived production parameters: total milk yield between 5 and 305 days (TMY305), peak milk yield (PMY), days at peak (DP) and persistency (P). Methods: 13,798 daily milk yield records from 1,510 cows performing in 103 herds were used; the total number of lactations was 2,480. Four models were considered: Wood, Wiltmink, Papajcsik & Bordero, and a second-degree polynomial. Mean square error, mean absolute error, mean square error of prediction, Akaike and Bayesian information criteria were used to select the model better describing each lactation using the majority rule, that is, the model selected by most criteria was the chosen one. The shape of each fitted lactation curve was checked using basic results from calculus which permitted the classification of the estimated curves into two groups: typical and atypical; only typical functions were used to compute the four aforementioned production parameters. Results: The second-order polynomial was the model most frequently selected, while the Papajcsik & Bordero model had the lowest frequency. Average TMY305, PMY, DP and P were 3,489.86 kg, 17.28 kg, 57.17 days, and 0.83, respectively, with coefficients of variation: 0.27, 0.21, 0.41, and 0.16. Conclusions: This study permitted to identify individuals with outstanding phenotypic performance. To the best of our knowledge, this is the first study of this kind involving thousands of lactations from Gyr cows performing in several regions of Colombian low tropic.

The formation of amyloid-like fibrils, which polymerize from various soluble proteins under physiological and acidic conditions, causes a wide range of protein-folding diseases, such as Alzheimer’s disease and Parkinson’s disease. Fibril assembly in in vitro solutions containing nitric oxide, a free radical that functions as an important signalling molecule involved in numerous physiological and pathological processes, has not been reported. Here, we investigated the protein assembly that occur in thyroglobulin under mildly acidic conditions in the presence of nitric oxide. Solution studies, size exclusion chromatography, dynamic light scattering and analytical ultracentrifugation, demonstrated the size changes of thyroglobulin oligomers after nitric oxide treatment. Following electron microscopic analysis visualized their structural changes and revealed that the molecules can morphologically form polymerized fibril assemblies with a length of 2–5 μm and width 10–100 nm. Taken together, these results provide suggestive evidence for the propensity of forming polymerized thyroglobulin fibrils implying their presence in thyroid cells, which may be related to the onset or progression of thyroid diseases.

The distribution of partial oxygen pressure (pO2) is analyzed for the anterior aspect of the left wrist with an amperometric oxygen microsensor composed of a small planar Pt disk-sensing area (diameter = 25 μm). The pO2 levels vary depending on the measurement location over the wrist skin, and they are systematically monitored in the analysis for both one-dimensional single line (along the wrist transverse crease) and two-dimensional square area of the wrist region. Relatively higher pO2 values are observed at certain area in close proximity to the position of acupuncture points with statistical significance, indicating strong relationship between oxygen and acupuncture point. The used oxygen microsensor is sensitive enough to detect the pO2 variation depending on the location. This study may provide information helpful to understand possible physiological roles of the acupuncture points.

Tnfaip8/oxidative stress regulated gene-α (Oxi-α) is a novel protein expressed specifically in brain dopaminergic neurons and its over-expression has been reported to protect dopaminergic cells against OS-induced cell death. In this study, murine C165S mutant Tnfaip8/Oxi-α has been crystallized and X-ray data have been collected to 1.8 Å using synchrotron radiation. The crystal belonged to the primitive orthorhombic space group P21212, with unit-cell parameters a = 66.9, b = 72.3, c = 93.5 Å. A full structural determination is under way in order to provide insights into the structure-function relationships of this protein.

Since radiation-induced caspase-dependent apoptosis and ROS generation were partially prevented by HSP25 overexpression, similar to the treatment of control cells with antioxidant agents such as DPI and tiron, questions arise whether radiation-mediated ROS generation contributes to the apoptotic cell death and also whether HSP25 overexpression can reduce ROS mediated apoptotic cell death. In the present study, radiation-induced cytochrome c release from mitochondria and activation of caspases accompanied by a decrease of mitochondrial membrane potential in Jurkat T cells were shown to be inhibited by mitochondrial complex I inhibitor rotenone, suggesting that mitochondrial ROS might be important in radiation-induced caspase-dependent apoptosis. When HSP25 was overexpressed, effects similar to the treatment of cells with the antioxidants were obtained, indicating that HSP25 suppressed radiation-induced mitochondrial alteration that resulted in apoptosis. Furthermore, activation of p38 MAP kinase by radiation was associated with radiation-induced cell death and ROS production and PKCδ was an upstream molecule for p38 MAP kinase activation, ROS generation and subsequent caspase-dependent apoptotic events. However, in the HSP25 overexpressed cells, the above-described effects were blocked. In fact, radiation-induced membrane translocation of PKCδ and tyrosine phosphorylation were inhibited by HSP25. Based on the above data, we suggest that HSP25 downregulates PKCδ, which is a key molecule for radiation-induced ROS generation and mitochondrial-mediated caspase-dependent apoptotic events.

The immunomodulatory effect of deer antler, which is used as traditional medicine, has been known, but the active component of antlers from Cervus elaphus has not been identified. In this study, we identified the immunomodulator from C. elaphus and examined its biological activities on the immune system. To identify an immunomodulator, we used bioassay-guided fractionation after silica gel column chromatography. Structural analysis was performed with one- and two-dimensional nuclear magnetic resonance techniques and tandem mass spectrometry coupled with fast atom bombardment. The subfraction, phosphatidylcholines, isolated 70% ethanol extract of C. elaphus induced the proliferation of spleen cells in synergy with concanavalin A. According to the structural analysis, phosphatidylcholines were classified as a family (1,2-alkyl- sn-glycerol-3-phosphocholines) containing arachidonyl (C20:4), stearoyl (C18:0), oleoyl (C18:1), linoleoyl (C18:2), palmitoyl (C16:0), and myristoyl (C14:0) chains in their fatty acyl chains. Because the unsaturated fatty acids showed an inhibitory effect on the immune system, dialkyl phosphatidylcholines with different chain lengths from C10:0 to C20:0 that stimulate the proliferation of spleen cells were examined extensively. Among other saturated phosphatidylcholines used, dimyristoyl phosphatidylcholine (C14:0) induced the proliferation of spleen cells more efficiently, whereas dimyristoleoyl phosphatidylcholine (C14:1) effected little change in the proliferation of spleen cells. These data collectively suggest that phosphatidylcholines with saturated fatty acyl chains are immunostimulating factors. They may modify the proliferation of known mitogens. Further, chain length and saturation of the fatty acids may play important roles in the proliferation of spleen cells.

El presente artículo, analiza la influencia de la cultura en los procesos de innovación y de negociación internacional, desde las diferencias culturales, que se convierten en insumo fundamental para garantizar una exitosa inserción en los procesos de negociación transfronteriza; y finalmente, se examina el perfil cultural del empresario colombiano, sus prerrogativas, los frutos derivados de tales negociaciones y por qué hacer negocios con los empresarios en Colombia. Se parte del enfoque de Hofstede (1980), denominado: La Teoría de las Dimensiones Culturales, como marco genérico para este análisis empírico, que permite identificar los valores culturales que afectan el comportamiento de los empresarios.

Tnfaip8/oxidative stress regulated gene-α (Oxi-α) is a novel protein expressed specifically in brain dopaminergic neurons and its over-expression has been reported to protect dopaminergic cells against OS-induced cell death. In this study, murine C165S mutant Tnfaip8/Oxi-α has been crystallized and X-ray data have been collected to 1.8 Å using synchrotron radiation. The crystal belonged to the primitive orthorhombic space group P21212, with unit-cell parameters a = 66.9, b = 72.3, c = 93.5 Å. A full structural determination is under way in order to provide insights into the structure-function relationships of this protein.

Introducción: la formación de pregrado en profesiones de las ciencias de la salud está compuesta por dos ciclos de formación: la fundamentación científica y la práctica disciplinar. Lo anterior genera una diferencia en tiempo de cerca de 18 meses entre las asignaturas de ciencias básicas y la práctica clínica, motivo por el cual los estudiantes presentan dificultades importantes para la integración y análisis disciplinar. Como alternativa de solución para mejorar los niveles de integración conceptual durante la fase de práctica clínica se propone la implementación de casos situacionales como estrategia para el desarrollo de la argumentación científica. Objetivo: analizar los resultados de la implementación del caso situacional en el aula de fisiología humana como estrategia para el desarrollo de las competencias en mentación en un grupo de estudiantes de pregrado de segundo semestre de los programas de enfermería y fisioterapia. Métodos: la investigación propuesta se realizó bajo el marco de la investigación cualitativa siguiendo un diseño descriptivo y de alcance interpretativo. Como población del trabajo de investigación se eligió el 10 % del grupo de estudiantes de la asignatura morfofisiología II del semestre 2019-1, muestra de tipo aleatorizada a conveniencia, para valorar el desarrollo de la competencia de argumentación científica en fisiología a partir de la ejecución de casos situacionales. La competencia argumentativa fue categorizada y evaluada a partir de la clasificación de competencias argumentativas de Ruiz Ortega (2015), la cual fue modificada para responder a las necesidades y los alcances de la argumentación en fisiología por parte de estudiantes de pregrado. Resultados: al comparar las respuestas de los estudiantes entre los diferentes momentos de resolución de los casos situacionales 1 y 2, se evidenció que el caso situacional como estrategia favorece la competencia argumentativa, ya que el 60 % de la muestra subió una a dos fases, el 20 % se mantiene estable y solamente el 20 % restante bajó una fase. Por lo tanto, un incremento en la competencia argumentativa puede llevar a un aumento en la capacidad de compresión y de pensamiento crítico, ya que: \"la argumentación es una habilidad central que puede empoderar a las personas jóvenes desarrollar niveles óptimos de alfabetización científica, desarrollar su pensamiento crítico y el razonamiento\". Conclusiones: el caso situacional como estrategia, en conjunto con con el diseño de actividades en el marco de un espacio de aprendizaje, genera avances de una a dos fases en la escala de valoración de la competencia argumentativa en estudiantes de pregrado de ciencias de la salud.