Fetal and adult cerebral artery K(ATP) and K(Ca) channel responses to long-term hypoxia.

High-altitude long-term hypoxia (LTH) alters cerebral vascular contractile and relaxation responses in both fetus and adult. We tested the hypotheses that LTH-mediated vascular responses were secondary to altered K+ channel function and that in the fetus these responses differ from those of the adult. In middle cerebral arteries (MCA) from both nonpregnant adult and fetal (approximately 140 days gestation) sheep, which were either acclimatized to high altitude (3,820 m) or sea-level controls, we measured norepinephrine (NE)-induced contractions and intracellular Ca2+ concentration ([Ca2+]i) simultaneously, in the presence or absence of different K+ channel openers or blockers. In adult MCA, LTH was associated with approximately 20% decrease in NE-induced tension and [Ca2+]i, with a significant increase in Ca2+ sensitivity. In contrast, in fetal MCA, LTH failed to affect significantly NE-induced contraction or [Ca2+]i but significantly decreased the ATP-sensitive K+ (K(ATP)) channel and Ca2+-activated K+ (K(Ca)) channel-mediated relaxation. The significant effect of K(ATP) and K(Ca) channel activators on the relaxation responses and the fact that K+ channels play a key role in myogenic tone support the hypotheses that K+ channels play an important role in hypoxia-mediated responses. These results also support the hypothesis of significant developmental differences with maturation from fetus to adult.     

Effect of microwave radiation on Bacillus subtilis spores

AIMS: To compare the killing efficacy and the effects exerted by microwaves and conventional heating on structural and molecular components of Bacillus subtilis spores. METHODS AND RESULTS: A microwave waveguide applicator was developed to generate a uniform and measurable distribution of the microwave electric-field amplitude. The applicator enabled the killing efficacy exerted by microwaves on B. subtilis spores to be evaluated in comparison with conventional heating at the same temperature value. The two treatments produced a similar kinetics of spore survival, while remarkably different effects on spore structures were seen. The cortex layer of the spores subjected to conductive heating was 10 times wider than that of the untreated spores; in contrast, the cortex of irradiated spores did not change. In addition, the heated spores were found to release appreciable amounts of dipicolinic acid (DPA) upon treatment, while extracellular DPA was completely undetectable in supernatants of the irradiated spores. These observations suggest that microwave radiation may promote the formation of stable complexes between DPA and other spore components (i.e. calcium ions); thus, making any release of DPA from irradiated spores undetectable. Indeed, while a decrease in measurable DPA concentrations was not produced by microwave radiation on pure DPA solutions, a significant lowering in DPA concentration was detected when this molecule was exposed to microwaves in the presence of either calcium ions or spore suspensions. CONCLUSIONS: Microwaves are as effective as conductive heating in killing B. subtilis spores, but the microwave E-field induces changes in the structural and/or molecular components of spores that differ from those attributable only to heat. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information on the effect of microwaves on B. subtilis spore components.     

Autoantibody profile in systemic lupus erythematosus with psychiatric manifestations: a role for anti-endothelial-cell antibodies

This study was performed to determine the correlation between psychiatric manifestations and several autoantibodies that might participate in the pathogenesis of psychiatric disorders in the course of systemic lupus erythematosus (SLE). Fifty-one unselected outpatients with SLE were enrolled. Psychiatric evaluation was performed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. The prevalence of antibodies against endothelial cells (AECA), cardiolipin, β2 glycoprotein I, Ro, Ro52, La, glial fibrillary acidic protein, ribosomal P protein, dsDNA, and nucleosomes was assessed by experimental and commercial enzyme-linked immunosorbent assays. According to the cutoff value, AECA were present in 11 of 17 (64.7%) SLE patients with psychosis and mood disorders and in 10 of 34 (29.4%) patients without psychiatric manifestations other than anxiety (P = 0.03). Moreover, the AECA binding index was significantly higher in the first group (P = 0.03). Conversely, no significant correlation was found between the presence of the other autoantibodies studied and psychiatric involvement. The results of this study suggest a relationship between AECA and psychosis and mood disorders in SLE, supporting the hypothesis of a biological origin of these disturbances.     

Small angle x-ray scattering of the hemoglobin from Biomphalaria glabrata

The hemoglobin from Biomphalaria glabrata is an extracellular respiratory protein of high molecular mass composed by subunits of 360 kDa, each one containing two 180 kDa chains linked by disulfide bridges. In this work, small angle x-ray scattering (SAXS) measurements were performed with the hemoglobin at pH 5.0 and 7.5. Radii of gyration of 98.6 +/- 0.5 and 101.8 +/- 0.2 A and maximum diameters of 300 +/- 10 and 305 +/- 10 A, respectively, were obtained from Guinier plot extrapolation and analytical curve fitting. The pair distance distribution functions p(r) corresponded to globular particles with a somewhat anisotropic shape for both preparations. Computer analysis of the low angle part of the scattering curve led to the determination of the low resolution envelope of the protein, revealing a P(222) symmetry. Shape reconstruction from ab initio calculations using the complete scattering curve furnished a compact prolate three-dimensional (3D) bead model for the protein. Hydrodynamic parameters were obtained from experiments and theoretical calculations using the 3D model. The results of the structural and biochemical studies reported herein indicate that the multisubunit structure of this hemoglobin is compatible with a tetrameric arrangement.     

Dietary restriction and fibre supplementation: oxidative stress and metabolic shifting for cardiac health

Dietary modification ought to be the first line of strategy in prevention of the development of cardiac disease. The purpose of this study was to investigate whether dietary restriction, dietary-fibre-enriched diet, and their interactions might affect antioxidant capacity and oxidative stress in cardiac tissue. Male Wistar rats (180-200 g; n=10) were divided into four groups: control ad libitum diet (C), 50% restricted diet (DR), fed with fibre-enriched diet (F), and 50% restricted fibre-enriched diet (DR-F). After 35 days of the treatments, F, DR, and DR-F rats showed low cholesterol, LDL-cholesterol, and triacylglycerol, and high HDL-cholesterol in serum. The DR, DR-F, and F groups had decreased myocardial lipoperoxide and lipid hydroperoxide. The DR-F and F treatments increased superoxide dismutase and glutatione peroxidase (GSH-Px). The DR treatment increased GSH-Px and catalase activities. Dietary fibre beneficial effects were related to metabolic alterations. The F and DR-F groups showed high cardiac glycogen and low lactate dehydrogenase/citrate synthase ratios, indicating diminished anaerobic and elevated aerobic myocardial metabolism in these animals. There was no synergistic effect between dietary restriction and dietary fibre addition, since no differences were observed in markers of oxidative stress in the F and DR-F groups. Dietary fibre supplementation, rather than energy intake and dietary restriction, appears to be the main process retarding oxidative stress in cardiac tissue.     

A novel application of solid state culture: production of lipases by Yarrowia lipolytica

An extracellular lipase was produced in solid state cultures of Yarrowia lipolytica CECT 1240 using nylon sponge and several food and agroindustrial wastes (barley bran and triturated nut) as, respectively, inert support and support substrate. The highest activity was obtained with triturated nut (23 kU l^–1) followed by sunflower oil-soaked barley bran (21 kU l^–1). The activities were 5 fold greater those obtained in the control cultures with just inert support.