The endocrine heart and natriuretic peptides: histochemistry, cell biology, and functional aspects of the renal urodilatin system

This review focuses on some selected aspects of the endocrine heart and natriuretic peptides. The endocrine heart is composed of specific myoendocrine cells of the cardiac atria. The myoendocrine cells synthesize and secrete the natriuretic peptide hormones which exhibit natriuretic, diuretic, and vasorelaxant properties. Immunohistochemical analyses show that natriuretic peptides of the A-type and B-type are localized not only in the specific granules of these myoendocrine cells but also in many other organs including the brain, adrenal medulla, and kidney. Also, their receptors are detected in many organs showing the multiple functions of these regulatory peptides. Of the members of the natriuretic peptide family, ANP (ANP for atrial natriuretic peptide; also denominated cardiodilatin, CDD), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and the A-type, including its renal form, urodilatin, are emphasized in this review. Urodilatin is localized in the kidney, differentially processed, and secreted into the urine. The intrarenal synthesis and secretion is the basis for a paracrine system regulating water and sodium reabsorption at the level of the collecting duct. CDD/ANP-1-126, cleaved from a precursor of 126 amino acids in the heart to a 28-amino acid-containing circulating molecular form (CDD/ANP-99-126), and urodilatin (CDD/ANP-95-126) share similar biochemical features and biological functions, but urodilatin may be more involved in the regulation of body fluid volume and water-electrolyte excretion, while circulating CDD/ANP-99-126 is responsible for blood pressure regulation. The physiological and pharmacological properties of these peptides have great clinical impact, and as a consequence urodilatin is involved in drug development for the treatment of acute renal failure, cardiomyopathia, and acute asthma.     

A photoelectron velocity map imaging spectrometer for experiments combining synchrotron and laser radiations

A velocity map imaging/ion time-of-flight spectrometer designed specifically for pump-probe experiments combining synchrotron and laser radiations is described. The in-house built delay line detector can be used in two modes: the high spatial resolution mode and the coincidence mode. In the high spatial resolution mode a kinetic energy resolution of 6% has been achieved. The coincidence mode can be used to improve signal-to-noise ratio for the pump-probe experiments either by using a gate to count electrons only when the laser is present or by recording coincidences with the ion formed in the ionization process.     

Olfactory bulb habituation to odor stimuli.

Habituation is a simple form of memory, yet its neurobiological mechanisms are only beginning to be understood in mammals. In the olfactory system, the neural correlates of habituation at a fast experimental timescale involving very short intertrial intervals (tens of seconds) have been shown to depend on synaptic adaptation in olfactory cortex. In contrast, behavioral habituation to odorants on a longer timescale with intertrial intervals of several minutes depends on processes in the olfactory bulb, as demonstrated by pharmacological studies. We here show that behavioral habituation to odorants on this longer timescale has a neuronal activity correlate in the olfactory bulb. Spiking responses of mitral cells in the rat olfactory bulb adapt to, and recover from, repeated odorant stimulation with 5-min intertrial intervals with a time course similar to that of behavioral habituation. Moreover, both the behavioral and neuronal effects of odor habituation require functioning N-methyl-d-aspartic acid receptors in the olfactory bulb. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of the residual stress state of coatings on the wear behavior in external turning of AISI 4140 and Ti–6Al–4V

The residual stress state of coatings influences tool life and performance in machining significantly. Due to thermo-mechanical loads during the cutting process the coatings require tailored properties. Beside the coating structure the two most important properties are the residual stress state and the chemical composition of the coating. Therefore, the influence of these two properties is investigated in this study, comparing the cutting performance in continuous and interrupted cutting of 42CrMo4 (AISI 4140) and Ti–6Al–4V. It is shown that the residual stress states of the coating close to the surface and close to the substrate are important for the wear behavior. High compressive residual stresses near the substrate combined with a material-optimized composition increase the resistance against chipping. Flank wear resistance increases with high compressive residual stresses near the surface and decreasing stresses towards the substrate.     

The Role of Oncostatin M and Its Receptor Complexes in Cardiomyocyte Protection,Regeneration, and Failure

Oncostatin M (OSM), a member of the interleukin-6 family, functions as a major mediator of cardiomyocyte remodeling under pathological conditions. Its involvement in a variety of human cardiac diseases such as aortic stenosis, myocardial infarction, myocarditis, cardiac sarcoidosis, and various cardiomyopathies make the OSM receptor (OSMR) signaling cascades a promising therapeutic target. However, the development of pharmacological treatment strategies is highly challenging for many reasons. In mouse models of heart disease, OSM elicits opposing effects via activation of the type II receptor complex (OSMR/gp130). Short-term activation of OSMR/gp130 protects the heart after acute injury, whereas chronic activation promotes the development of heart failure. Furthermore, OSM has the ability to integrate signals from unrelated receptors that enhance fetal remodeling (dedifferentiation) of adult cardiomyocytes. Because OSM strongly stimulates the production and secretion of extracellular proteins, it is likely to exert systemic effects, which in turn, could influence cardiac remodeling. Compared with the mouse, the complexity of OSM signaling is even greater in humans because this cytokine also activates the type I leukemia inhibitory factor receptor complex (LIFR/gp130). In this article, we provide an overview of OSM-induced cardiomyocyte remodeling and discuss the consequences of OSMR/gp130 and LIFR/gp130 activation under acute and chronic conditions.     

Impedance of a porous electrode with an axial gradient of concentration

When the impedance is measured on a battery, an inductive impedance is often observed in a high frequency range. This inductance is frequently related to the cell geometry and electrical leads. However, certain authors claimed that this inductance is due to the concentration distribution of reacting species through the pores of battery electrodes. Their argument is based on a paper in which a fundamental error was committed. Hence, the impedance is re-calculated on the basis of the same principle. The model shows that though the diffusion process plays an outstanding role, the overall reaction rate is never completely limited by this process. The faradaic impedance due to the concentration distribution is capacitive. Therefore, the inductive impedance observed on battery systems cannot be, by any means, attributed to the concentration distribution inside the pores. Little frequency distribution is found and the impedance is close to a semi-circle. Therefore depressed impedance diagrams in porous electrodes without forced convection cannot be ascribed to either a Warburg nor a Warburg-de Levie behaviour.Nomenclature A D¦C¦ (mole cm s^–1) - B j+K¦C¦ (mole cm s^–1) - b Tafel coefficient (V^–1) - C(x) Concentration ofS in a pore at depthx (mole cm^–3) - C ₀ Concentration ofS in the solution bulk (mole cm^–3) - C C(x) change under a voltage perturbation (mole cm^–3) - ¦C¦ Amplitude of C (mole cm^–3) - D Diffusion coefficient (cm² s^–1) - E Electrode potential (V) - E Small perturbation inE namely a sine-wave signal (V) - ¦E¦ Amplitude of E(V) - F Faraday constant (96500 A s mol^–1) - F(x) Space separate variable forC - f Frequency in Hz (s^–1) - g(x) KC(x)¦E¦(mole cm s^–1) - I Apparent current density (A cm^–2) - I _st Steady-state current per unit surface of pore aperture (A cm^–2) - j Imaginary unit [(–1)^1/2] - K Pseudo-homogeneous rate constant (s^–1) - K Potential derivative ofK, dK/dE (s^–1 V^–1) - K ^* Heterogeneous reaction rate constant (cm s^–1) - L Pore depth (cm) - n Reaction order - P Reaction product - p Parameter forF(x), see Equation 13 - q Parameter forF(x), see Equation 13 - R _e Electrolyte resistance (ohm cm) - R _p Polarization resistance per unit surface of pore aperture (ohm cm²) - R _t Charge transfer resistance per unit surface of pore aperture (ohm cm²) - S Reacting species - S _a Total surface of pore apertures (cm²) - S ₀ Geometrical surface area - S _p Developed surface area of porous electrode per unit volume (cm² cm^–3) - s Concentration gradient (mole cm^–3 cm^–1) - t Time - U Ohmic drop - x Distance from pore aperture (cm) - Z Faradaic impedance per unit surface of pore aperture (ohm cm²) - Z _x Local impedance per unit pore length (ohm cm³) - z Charge transfer number - Porosity - Thickness of Nernst diffusion layer - Penetration depth of reacting species (cm) - Penetration depth of a.c. signal determined by the potential distribution (cm) - Electrolyte (solution) resistivity (ohm cm) - ₀ Flow of S at the pore aperture (mole cm² s^–1) - Angular freqeuncy of a.c. signal, 2f(s^–1) - Integration constant     

Evaluation of rapeseed meals in broiler chicks: Effect of iodine supply and glucosinolate degradation by myrosinase or copper

In rapeseed meals (RSM) of a conventional (c) or a newly bred (n) variety 117 or 44 mmol glucosinolates and glucosinolate degradation products per kg dry matter were detected. Soaking meals in aqueous myrosinase or copper sulphate solution and subsequent drying reduced the content of antinutrients by more than 90%. Broiler chickens were fed (i) a glucosinolate-free diet, or this diet in which half the soybean meal was replaced by RSM of various origins and treatment; (ii) untreated cRSM; (iii) cRSM treated with myrosinase: (iv) cRSM treated with Cu (v) untreated nRSM; or (vi) nRSM treated with myrosinase. These diets were administered with or without supplementary iodine. Chickens receiving the iodine-deficient diets with myrosinase-treated RSM showed growth depression, incomplete feathering, leg injuries and severe goitre. In the serum T⁴ could not be detected. Giving myrosinase-treated RSM plus iodine, or giving other RSM diets irrespective of iodine administration, no growth depression was observed. RSM diets without iodine dosage markedly increased thyroid weight: there were no differences between the RSM variants. In contrast to the treatment with myrosinase, in the sera of the chickens fed on untreated RSM or RSM treated with copper T⁴ could be detected, suggesting that in iodine-deficient conditions differences in serum T⁴ concentration between RSM groups indicate a differing anti-thyroid activity. With iodine supplementation the RSM had a significant effect on thyroid weight. The largest thyroids (five-fold heavier) were in the animals with myrosinase-treated cRSM. The untreated cRSM and the nRSM trebled or doubled the thyroid weight, and the myrosinase-treated nRSM trebled it. The thyroid weight of chicks fed cRSM treated with copper did not differ significantly from the glucosinolate-free control. There was evidence that heating the myrosinase-treated RMS produced anti-thyroid compounds; these should be identified in further investigations.     

Determination of mechanical properties of thin films: a theoretical feasibility study

The aim of this work was to determine the principal mechanical parameters of a thin film on a substrate, i.e. Young's modulus, Poisson's ratio, intrinsic stress, and coefficient of linear thermal expansion. First, standard experiments possibly suitable for this purpose were investigated theoretically. The margin of error of the mechanical parameters determined was estimated as dependent on the geometrical conditions, substrate properties, and error in the respective measurements. In addition, the homogeneity and stability of the parameters were taken into account, for instance inhomogeneity of the film thickness and possible modification of substrate parameters during film growth. To obtain meaningful results, the accuracy of the measurements as well as the homogeneity and stability of several geometrical and physical parameters in general must be extremely high. However, the experimental conditions were found to fulfill these requirements.