Cardioprotective Effect of Beta-3 Adrenergic Receptor Agonism Role of Neuronal Nitric Oxide Synthase

ObjectivesThe aim of this study was to determine whether activation of β3-adrenergic receptor (AR) and downstream signaling of nitric oxide synthase (NOS) isoforms protects the heart from failure and hypertrophy induced by pressure overload.Backgroundβ3-AR and its downstream signaling pathways are recognized as novel modulators of heart function. Unlike β1- and β2-ARs, β3-ARs are stimulated at high catecholamine concentrations and induce negative inotropic effects, serving as a “brake” to protect the heart from catecholamine overstimulation.MethodsC57BL/6J and neuronal NOS (nNOS) knockout mice were assigned to receive transverse aortic constriction (TAC), BRL37344 (β3 agonist, BRL 0.1 mg/kg/h), or both.ResultsThree weeks of BRL treatment in wild-type mice attenuated left ventricular dilation and systolic dysfunction, and partially reduced cardiac hypertrophy induced by TAC. This effect was associated with increased nitric oxide production and superoxide suppression. TAC decreased endothelial NOS (eNOS) dimerization, indicating eNOS uncoupling, which was not reversed by BRL treatment. However, nNOS protein expression was up-regulated 2-fold by BRL, and the suppressive effect of BRL on superoxide generation was abrogated by acute nNOS inhibition. Furthermore, BRL cardioprotective effects were actually detrimental in nNOS–/– mice.ConclusionsThese results are the first to show in vivo cardioprotective effects of β3-AR–specific agonism in pressure overload hypertrophy and heart failure, and support nNOS as the primary downstream NOS isoform in maintaining NO and reactive oxygen species balance in the failing heart

Effecten van individuele attitudes en van de attitudes van de peer group op de prestaties voor wiskunde van jongens en meisjes

In this study we investigated whether the gender gap in favour of girls in mathematics achievement can be explained not only by gender differences in attitudes and behaviour but also by the attitudes of the peer group. Multilevel analyses were carried out on the LOSO-data. The results showed that girls have more positive attitudes towards schooling and behave better at school and that once these gender differences were taken into account, the gender gap in mathematics achievement disappeared. We found that the gender gap became smaller, the more boys and girls had positive attitudes towards schooling. Moreover, the results indicated that the attitudes of the peer group had effects on the mathematics achievement of boys and girls: girls and boys performed better in groups with high positive attitudes towards schooling than in groups with low positive attitudes towards schooling (A-curriculum)

Properties of gelatin-gum arabic coacervates composited with amino resins

Only a small percent of the formaldehyde added to the coacervation solution is actually utilized for crosslinking the gelatin and gum arabic in the dense coacervate phase, the rest remaining in the colloid-poor solution. It was aimed to use this formaldehyde in the solution in a polymerization reaction with urea to form a composite film of gelatin-gum arabic coacervate within a supramolecular structure of the urea-formaldehyde resin. Part of the urea added reacts with formaldehyde used for crosslinking, opening up the polymer chains, and part reacts with free formaldehyde to form urea-formaldehyde resin phase grafted onto the coacervated macromolecules. The physical properties of the composite film investigated in this work, i.e. water absorbance, water vapor sorption and permeability, are interpreted as a function of the structure evolving as a result of the competing crosslinking and polymerization reactions. Copyright © 1993 Society of Chemical Industr