Evaluation of oxidant-antioxidant balance in patients on maintenance haemodialysis: a comparative study of dialyzers membranes.

BACKGROUND: Haemodialysis (HD) exacerbates oxidative stress (OS). The polymethyl-methacrylate (PMMA)-BK-F membrane ameliorates OS and inflammation markers compared to polyacrylonitrile (PAN/AN69) and cellulose membranes. This may be due to the size of pore radius, high flux or other specific properties of PMMA membranes. AIM: To compare OS and inflammatory status in HD-treated end stage renal disease patients with membranes of different pore size radius and flux. METHODS: 47 patients of both sexes were studied. The HD membranes with which the patients were normally treated were changed to BK-P or B-3 membranes for 6 months. Intracellular and extracellular components of the oxidant-antioxidant balance (OAB), C-reactive protein (CRP), beta2-micro-globulin (beta2mu-globulin), albumin and transferrin were measured. RESULTS: A significant decrease in red cell membrane thiobarbituric acid reacting substances and an increase in cytosolic superoxide dismutase (SOD) and plasma total antioxidant substances were observed in all patients after 6 months of treatment with BK-P and B-3 membranes except SOD and CRP in patients previously dialysed with triacetate cellulose membranes. Albumin and transferrin remained unmodified. beta2mu-globulin significantly decreased after treatment with PMMA membranes. CONCLUSION: BK-P and B-3 HD membranes improved the OAB, beta2mu-globulin and CRP compared to PAN/AN69 and cellulose diacetate membranes.

Neurogenin promotes neurogenesis and inhibits glial differentiation by independent mechanisms.

The mechanisms by which neural stem cells give rise to neurons, astrocytes, or oligodendrocytes are beginning to be elucidated. However, it is not known how the specification of one cell lineage results in the suppression of alternative fates. We find that in addition to inducing neurogenesis, the bHLH transcription factor neurogenin (Ngn1) inhibits the differentiation of neural stem cells into astrocytes. While Ngn1 promotes neurogenesis by functioning as a transcriptional activator, Ngn1 inhibits astrocyte differentiation by sequestering the CBP-Smad1 transcription complex away from astrocyte differentiation genes, and by inhibiting the activation of STAT transcription factors that are necessary for gliogenesis. Thus, two distinct mechanisms are involved in the activation and suppression of gene expression during cell-fate specification by neurogenin.

Neuronal activity-dependent cell survival mediated by transcription factor MEF2.

During mammalian development, electrical activity promotes the calcium-dependent survival of neurons that have made appropriate synaptic connections. However, the mechanisms by which calcium mediates neuronal survival during development are not well characterized. A transcription-dependent mechanism was identified by which calcium influx into neurons promoted cell survival. The transcription factor MEF2 was selectively expressed in newly generated postmitotic neurons and was required for the survival of these neurons. Calcium influx into cerebellar granule neurons led to activation of p38 mitogen-activated protein kinase-dependent phosphorylation and activation of MEF2. Once activated, MEF2 regulated neuronal survival by stimulating MEF2-dependent gene transcription. These findings demonstrate that MEF2 is a calcium-regulated transcription factor and define a function for MEF2 during nervous system development that is distinct from previously well-characterized functions of MEF2 during muscle differentiation.

[Efficiency of essential oil (Satureja montana) in controlling the ascospherosis in the honey bee (Apis mellifera) under field conditions.]. / Eficacia del aceite esencial de ajedrea (Satureja montana) en el control de la ascosferosis de la abeja (Apis mellifera) en condiciones de campo.

With the aim of testing its effect in the control of ascosphaerosis in bees, the essential oil of ajedra was incorporated into three types of feed in five different concentrations. Syrup (water and honey) with 0.1% were the best tolerated by the bees, with no colonial changes after a single feed. Later, the ascosphaerosis was introduced in a controlled manner into eight hives. For this, a 10 e6/ml spore suspension was applied by nedulisor three times a week for four weeks to ensure its abundant presence inside the hives. This was continued for the next four weeks period, and at the same time portions of brood-comb in a known state (24 h before operculation) were removed from the hives and heat shocked for 24 h (22 -/+ 2 degrees C), then replaced in the hives for their opercultion, finally removing them and maintaining them at 35 degrees C and 70% relative humidity until the appearance of typical disease symptoms (mummification of the larvae).The hives were randomly divided into two groups of four. One group received 500 ml of syrup with 0.1% oil of ajedra, twice a week for four weeks. The other was kept as the control, receiving syrup without medication. 27.6% of the selected larvae in the treated hives showed mummification, compared with 79.1% in the control hives. The treatment was perfectly tolerated by the bee colonies, showing no changes in their subsequent development.

Regulation of gliogenesis in the central nervous system by the JAK-STAT signaling pathway.

A mechanism by which members of the ciliary neurotrophic factor (CNTF)-leukemia inhibitory factor cytokine family regulate gliogenesis in the developing mammalian central nervous system was characterized. Activation of the CNTF receptor promoted differentiation of cerebral cortical precursor cells into astrocytes and inhibited differentiation of cortical precursors along a neuronal lineage. Although CNTF stimulated both the Janus kinase-signal transducer and activator of transcription (JAK-STAT) and Ras-mitogen-activated protein kinase signaling pathways in cortical precursor cells, the JAK-STAT signaling pathway selectively enhanced differentiation of these precursors along a glial lineage. These findings suggest that cytokine activation of the JAK-STAT signaling pathway may be a mechanism by which cell fate is controlled during mammalian development.

Interaction of Pd(II) and Pt(II) Amino Acid Complexes With Dinucleotides.

The interaction of the dinucleotides d(ApG) and d(ApA) with [Pd(aa)Cl(2)], where aa = L- or D-histidine or the methyl ester of L-histidine, and with [Pt(Met)Cl(2)], where Met = L-methionine was studied by (1)H and (13)C NMR and CD measurements. In the case of the L-histidine and L-histidineOMe, the reaction with d(ApG) appeared to give the bifunctional adducts Pd(L-Histidine)N1(1)N7(2) and Pd(L-HisOMe)N1(1)N7(2), but the behavior with D-histidine suggested the formation of the monofunctional adduct Pd(D-His)N7(2). The reaction of L-histidine with d(ApA) seemed to form the bimetallic adduct (L-His)PdN7(1)N7(2)Pd(L-His). The Pt(II)-L-methionine complex in both reactions with d(ApG) and d(ApA) seemed to yield mainly adducts Pt(L-Met)N7(1)N7(2) but the existence of adducts Pt(L-Met)N1(1)N7(2) cannot be ruled out.

"A contribution towards the study of Madrid air mycoflora. II. Genus Cladosporium".

The genus Cladosporium was isolated from the atmospheric air of Madrid with a high frequency and proportion being found in the four areas, tested. No significant differences existed between them. From the study of the correlation matrices of the number of colonies of Cladosporium with meteorological and chemical contamination parameters, we can conclude that mean temperature, relative atmospheric humidity and carbon monoxide level seem to have a positive influence on the concentration of Cladosporium spores in atmospheric air. On the other hand, the direction of the wind and the level of sulfur dioxide seem to have a negative influence on the spores concentration.

Contribution towards the study of the Madrid air mycoflora. I. Station diversity and seasonal variation.

The Madrid air mycoflora is made up of a number of groups which we have named "the normal mycoflora", since the frequency of its appearance was high. The other big group whose frequency of appearance was much less we have named "the sporadic mycoflora". The mean concentration of spores in the Madrid air is 375 spores/m3. From the study, by areas, of the city, we find that the fungal species which make up the normal flora are the same in all of them although their frequency of appearance presents small fluctuations. The fungal species which constitute the sporadic flora were not present in all of the observation stations, probably due to fluctuations which determine their small numbers. From the diversity study of the fungi population in the ecosystem, we can deduce that the two sample methods give us similar results. For this type of study therefore, the volumetric method is just as valid as the gravimetric. From the study of the seasonal spectrums of diversity we find that this fluctuates throughout the year within the limits of 1,78 and 3,61 bits/colony, which means that the ecosystem which is the object of study, is not subject to big disturbances.