The effects of physical exercise on plasma levels of relaxin, NTproANP, and NTproBNP in patients with ischemic heart disease

The insulin-like and vasodilatatory polypeptide relaxin (RLX), formerly known as a pregnancy hormone, has gained interest as a potential humoral mediator in human heart failure. Controversy exists about the relation between plasma levels of RLX and the severity of heart failure. The present study was designed to determine the course of RLX, atrial, and brain natriuretic peptide (NT-proANP and NT-proBNP) during physical exercise in patients with ischemic heart disease (IHD) and to relate hormone levels to peak cardiac power output (CPO) as a measure of cardiopulmonary function with prognostic relevance. 40 patients with IHD were studied during right-heart-catheterization at rest and during supine bicycle ergometry. RLX, NTproBNP, and NTproANP were determined before, during exercise, and after recovery. NT-proANP and NT-proBNP levels increased during maximal charge, and recovery while RLX levels decreased. Cardiac power output at maximal charge correlated inversely with NTproANP and NTproBNP but positively with RLX. Patients with high degree heart failure (CPO < 1.96 W) had higher NTproANP and NTproB-NP and lower RLX levels than patients with low degree heart failure. While confirming the role of NTproANP and NTproBNP as markers for the severity of heart failure, the present data do not support the concept that plasma levels of RLX are related to the severity of myocardial dysfunction and that systemic RLX acts as a compensatory vasodilatatory response hormone in ischemic heart disease

Are food-deceptive orchid species really functionally specialized for pollinators?

Food-deceptive orchid species have traditionally been considered pollination specialized to bees or butterflies. However, it is unclear to which concept of specialization this assumption is related; if to that of phenotypic specialization or of functional specialization. The main aim of this work was to verify if pollinators of five widespread food-deceptive orchid species (Anacamptis morio (L.) R.M. Bateman, Pridgeon & M.W. Chase, Anacamptis pyramidalis (L.) Rich., Himantoglossum adriaticum H. Baumann, Orchis purpurea Huds. and Orchis simia Lam.) predicted from the phenotypic point of view matched with the observed ones. We addressed the question by defining target orchids phenotypic specialization on the basis of their floral traits, and we compared the expected guilds of pollinators with the observed ones. Target orchid pollinators were collected by conducting a meta-analysis of the available literature and adding unpublished field observations, carried out in temperate dry grasslands in NE Italy. Pollinator species were subsequently grouped into guilds and differences in the guild spectra among orchid species grouped according to their phenotype were tested. In contradiction to expectations derived from the phenotypic point of view, food-deceptive orchid species were found to be highly functionally generalized for pollinators, and no differences in the pollinator guild spectra could be revealed among orchid groups. Our results may lead to reconsider food-deceptive orchid pollination ecology by revaluating the traditional equation orchid-pollination specialization