Interpopulation characterization of quinoa (Chenopodium quinoa Willd.) from different agroecological environments of Colombia.

Chenopodium quinoa Willd. it is an Andean cereal of great importance for human consumption due to its high nutritional value. In Colombia there is a high phenotypic and genotypic variability within quinoa crops, which has not been studied and has been maintained by the same farmers cycle after production cycle. The objective of this study was to carry out an interpopulation characterization of quinoa cultivated in different producing municipalities of the department of Boyacá, in Colombia, for which 19 morphological descriptors were used, which were evaluated in situ in nine municipalities and analyzed through descriptive statistics, principal component analysis, correlation and conglomerates. In the evaluation of the quantitative traits for all the populations, it was observed that the most variable descriptors were Number of teeth lower leaf (DHI), Lower leaf length (LHI), Width upper leaf (AHI) and Number of teeth upper leaf (DHS). Great segregation between and within individuals of Blanca de Jericó and Piartal was observed for panicle and leaf color and shape, stem color, presence of teeth, and axils on upper and lower leaves. A classification key is proposed that allows in the field to be able to morphologically differentiate the genotypes of Piartal and Blanca de Jericó. This research shows that among the most cultivated genotypes in the department of Boyacá, there is still an important phenotypic diversity given at the inter and intra-individual level, due to the phenological state and the agroclimatological conditions of the different producing regions.

Cardiac-respiratory gating method for magnetic resonance imaging of the heart.

In studies of transmural myocardial function, acquisitions of high spatial and temporal resolution tagged cardiac images often exceed the practical time limit for breath-hold fast imaging techniques. Therefore, a dual cardiac-respiratory gating device has been constructed to acquire SPAMM-tagged cardiac MR images at or near end-expiration during spontaneous breathing, by providing an external trigger to a conventional MRI system. Combined cardiac and respiratory gating essentially eliminates the respiratory motion artifacts in tagged cardiac MR images. Compared to cardiac-gated images obtained during intermittent breath-holds, cardiac-respiratory gated images show improved tag-myocardium contrast due to magnetization recovery during inspiration.

Regulation by glucose availability of tension development and electrical activity in fetal and neonatal rat hearts.

The aim of the present article was to study if changes in glucose availability modify the functional activity of the glucose-dependent developing heart. Our data indicate that a decrease in glucose availability increases tension development and action potential duration at early fetal stages. This fact could probably be explained by the enhancement of Ca2+ movements that regulate the number and turnover rate of membrane glucose transporters in muscle cells. The sensitivity to glucose availability decreases postnatally as the heart becomes fatty acid-dependent.

Trifluoperazine inhibition of insulin-induced increase in skeletal muscle glucose uptake.

The ability of trifluoperazine, a calmodulin blocker, to prevent increases in skeletal muscle glucose uptake induced by insulin was tested. Insulin significantly increased glucose uptake by the rat hindlimb and trifluoperazine (10(-6) M) completely inhibited this increase. We conclude that calmodulin is a factor involved in the regulation of insulin-mediated glucose transport in muscle cells.