Plasma noradrenaline correlates to sympathetic muscle nerve activity in normotensive man

Recordings of multiunit sympathetic activity were made in muscle branches of the peroneal nerve in 22 healthy subjects at rest in recumbent position. Nerve activity was quantitated in terms of burst incidence (number of pulse synchronous sympathetic bursts per 100 heart beats or per min). In a separate session, 4-45 months later, blood was drawn from an antecubital vein for noradrenaline analysis. Both sympathetic activity and plasma concentrations of noradrenaline varied widely between subjects and both parameters increased with age. There was a significant positive correlation between a subject's level of sympathetic activity and his plasma concentration of noradrenaline. It is suggested that overflow of transmitter from sympathetic terminals in muscles contributes significantly to plasma levels of noradrenaline at rest.     

Relationship between plasma phospholipid transfer protein activity and HDL subclasses among patients with low HDL and cardiovascular disease

NK lysin is a 9-kDa polypeptide that was originally isolated from porcine intestinal tissue based on its antibacterial activity. It is produced by cytolytic lymphocytes and is cytolytic against a number of different types of tumor cells. Here we report the binding of NK lysin to lipopolysaccharide (LPS) and its anti-LPS activity. NK lysin binds to matrix-coated LPS from Escherichia coli, Pseudomonas aeruginosa, and different strains of Salmonella enterica. Lipid A and polymyxin B inhibited the binding, demonstrating a preferential interaction of NK lysin with the lipid part of LPS. Chromium-labeled lymphoma cells were lysed by NK lysin, and LPS dose-dependently inhibited the cytolysis at equimolar amounts. In the same manner, NK lysin inhibited certain LPS-stimulated effects on mouse bone marrow cells as well as LPS binding to mouse granulocytes. These results suggest that NK lysin may be a another natural LPS-binding protein from lymphocytes that may participate in the endogenous defense response associated with elevated concentrations of LPS.     

Critical aspects of sinter-hardening of prealloyed Cr–Mo steel

In recent years, growing demand for greater mechanical properties of PM steel components with competitive fabrication cost has led to significant innovations in different fields of powder metallurgy. Recent research has been focused on reaching higher performance with lower cost. To this end, the possibility of combining the conventional sintering and post-sintering processes for a particular powder composition has been introduced. Sinter-hardening is a result of the research conducted along this line. Elimination of any secondary operation such as quench-hardening by incorporating it in the sintering process (i.e. sinter-hardening) is of great interest, as it will lead to lower processing costs and equal, if not higher mechanical performance. However, to ensure the desired mechanical properties of the final component and robustness of the performance, critical aspects of the sinter-hardening process should be rigorously studied.Hence with specific attention to a Cr–Mo steel powder (FL-5305), this study deals with the influence of density on cooling rate, the effect of different sintering temperatures (e.g. 1120 °C and 1250 °C) on austenite grain size and consequently, hardenability. The microstructure development in sinter-hardened FL-5305 material has been analyzed and predicted by means of the available literature for solid steel and also using the commercial software (JMatPro 5.0) for materials assessment based on thermodynamic and kinetics modeling. Finally, inaccurate carbon control and its adverse impact on excessive formation of cementite have been addressed.     

Regioselectivity of nitroglycerin denitration by flavoprotein nitroester reductases purified from two Pseudomonas species

Two species of Pseudomonas capable of utilizing nitroglycerin (NG) as a sole nitrogen source were isolated from NG-contaminated soil and identified as Pseudomonas putida II-B and P. fluorescens I-C. While 9 of 13 laboratory bacterial strains that presumably had no previous exposure to NG could degrade low concentrations of NG (0.44 mM), the natural isolates tolerated concentrations of NG that were toxic to the lab strains (1.76 mM and higher). Whole-cell studies revealed that the two natural isolates produced different mixtures of the isomers of dinitroglycerol (DNG) and mononitroglycerol (MNG). A monomeric, flavin mononucleotide-containing NG reductase was purified from each natural isolate. These enzymes catalyzed the NADPH-dependent denitration of NG, yielding nitrite. Apparent kinetic constants were determined for both reductases. The P. putida enzyme had a Km for NG of 52 +/- 4 microM, a Km for NADPH of 28 +/- 2 microM, and a Vmax of 124 +/- 6 microM x min(-1), while the P. fluorescens enzyme had a Km for NG of 110 +/- 10 microM, a Km for NADPH of 5 +/- 1 microM, and a Vmax of 110 +/- 11 microM x min(-1). Anaerobic titration experiments confirmed the stoichiometry of NADPH consumption, changes in flavin oxidation state, and multiple steps of nitrite removal from NG. The products formed during time-dependent denitration reactions were consistent with a single enzyme being responsible for the in vivo product distributions. Simulation of the product formation kinetics by numerical integration showed that the P. putida enzyme produced an approximately 2-fold molar excess of 1,2-DNG relative to 1,3-DNG. This result could be fortuitous or could possibly be consistent with a random removal of the first nitro group from either the terminal (C-1 and C-3) positions or middle (C-2) position. However, during the denitration of 1,2-DNG, a 1.3-fold selectivity for the C-1 nitro group was determined. Comparable simulations of the product distributions from the P. fluorescens enzyme showed that NG was denitrated with a 4.6-fold selectivity for the C-2 position. Furthermore, a 2.4-fold selectivity for removal of the nitro group from the C-2 position of 1,2-DNG was also determined. The MNG isomers were not effectively denitrated by either purified enzyme, which suggests a reason why NG could not be used as a sole carbon source by the isolated organisms.