Fat intake and cardiovascular response

High dietary fat intake is a major risk factor for the development of obesity, which is frequently associated with diseases such as hypertension and diabetes and thus accelerated atherosclerosis. Angiotensin II and endothelin-1 are powerful growth factors and vasoconstrictors implicated in regulating vascular tone, vascular structure, and inflammation. Reduced bioactivity of nitric oxide and increased formation of reactive oxygen species (ROS) have been associated with obesity and high dietary fat intake. This article reviews the effects of high-fat diet on vascular functional changes in rodents and humans. Changes include alterations in vasoconstrictor function and receptor expression, and modulators of endothelium-dependent vascular tone (eg, nitric oxide- or endothelium-dependent contracting factor-mediated responses). Novel vasodilator effects of ROS and the anatomic heterogeneity of vascular responses are discussed. The beneficial effects of vasoactive mediators on vascular function could play a role for susceptibility to obesity-dependent hypertension, which is present in many, but not all, obese patients

A systematic survey of floral nectaries

The construction of classifications, as well as the understanding of biological diversity, depends upon a careful comparison of attributes of the organisms studied (Stuessy, 1990). It is widely known that data from diverse sources showing differences from taxon to taxon are of systematic significance. Dur-ing the 20th century, systematists have emphasized that their discipline involves a synthesis of all knowledge (Stevens, 1994) or, in other words, the variation of as many relevant characters as possible should be incorporated into the natural system to be constructed. The extent to which particular characters are constant or labile will determine their usefulness to syste-matics. In general, more conservative characters will be valuable in defining families and orders, whereas more labile characters may be useful at the ge-neric and specific levels (Webb, 1984). There is no doubt that floral characters are among the most used in the classification of flowering plants. At the same time, they constitute essential features in diagnostic keys to taxa in both taxonomic treatments and Floras (Cronquist, 1981, 1988).Fil: Bernardello, Gabriel Luis Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin