Studies of the renal effects of angiotensin II receptor blockade: the confounding factor of acute water loading on the action of vasoactive systems.

The acute renal tubular effects of two pharmacologically distinct angiotensin II receptor antagonists have been evaluated in normotensive volunteers on various salt diets. In the first study, the renal response to a single oral dose of losartan (100 mg) was assessed in subjects on a low (50 mmol Na/d) and on a high (200 mmol Na/d) salt intake. In a second protocol, the renal effects of 50 mg irbesartan were investigated in subjects receiving a 100 mmol Na/d diet. Both angiotensin II antagonists induced a significant increase in urinary sodium excretion. With losartan, a modest, transient increase in urinary potassium and a significant increase in uric acid excretion were found. In contrast, no change in potassium and uric acid excretions were observed with irbesartan, suggesting that the effects of losartan on potassium and uric acid are due to the intrinsic pharmacologic properties of losartan rather than to the specific blockade of renal angiotensin II receptors. Assessment of segmental sodium reabsorption using lithium as a marker of proximal tubular reabsorption demonstrated a decreased distal reabsorption of sodium with both antagonists. A direct proximal tubular natriuretic effect of the angiotensin II antagonist could be demonstrated only with irbesartan. This apparent discrepancy allowed us to reveal the importance of acute water loading as a possible confounding factor in renal studies. The results of the present analysis show that acute water loading per se may enhance renal sodium excretion and hence modify the level of activity of the renin-angiotensin system expected from a given sodium diet. Since acute water loading is a common practice in clinical renal studies, this confounding factor should be taken into account when investigating the renal effects of vasoactive systems.

Mass conservative three-dimensional water tracer distribution from Markov chain Monte Carlo inversion of time-lapse ground-penetrating radar data

Time-lapse geophysical measurements are widely used to monitor the movement of water and solutes through the subsurface. Yet commonly used deterministic least squares inversions typically suffer from relatively poor mass recovery, spread overestimation, and limited ability to appropriately estimate nonlinear model uncertainty. We describe herein a novel inversion methodology designed to reconstruct the three-dimensional distribution of a tracer anomaly from geophysical data and provide consistent uncertainty estimates using Markov chain Monte Carlo simulation. Posterior sampling is made tractable by using a lower-dimensional model space related both to the Legendre moments of the plume and to predefined morphological constraints. Benchmark results using cross-hole ground-penetrating radar travel times measurements during two synthetic water tracer application experiments involving increasingly complex plume geometries show that the proposed method not only conserves mass but also provides better estimates of plume morphology and posterior model uncertainty than deterministic inversion results.

Measurement of absolute cell volume, osmotic membrane water permeability, and refractive index of transmembrane water and solute flux by digital holographic microscopy.

ABSTRACT. A dual-wavelength digital holographic microscope to measure absolute volume of living cells is proposed. The optical setup allows us to reconstruct two quantitative phase contrast images at two different wavelengths from a single hologram acquisition. When adding the absorbing dye fast green FCF as a dispersive agent to the extracellular medium, cellular thickness can be univocally determined in the full field of view. In addition to the absolute cell volume, the method can be applied to derive important biophysical parameters of living cells including osmotic membrane water permeability coefficient and the integral intracellular refractive index (RI). Further, the RI of transmembrane flux can be determined giving an indication about the nature of transported solutes. The proposed method is applied to cultured human embryonic kidney cells, Chinese hamster ovary cells, human red blood cells, mouse cortical astrocytes, and neurons.

Audit report on the Evansdale Municipal Water Works, Evansdale, Iowa for the year ended June 30, 2010

Audit report on the Evansdale Municipal Water Works, Evansdale, Iowa for the year ended June 30, 2010

Networking the unemployed : Can policy interventions facilitate access to employment through informal channels ?

It is widely known that informal contacts and networks constitute a major advantage when searching for a job. Unemployed people are likely to benefit from such informal contacts, but building and sustaining a network can be particularly difficult when out of employment. Interventions that allow unemployed people to effectively strengthen their networking capability could as a result be promising. Against this background, this article provides some hints in relation to the direction that such interventions could take. First, on the basis of data collected on a sample of 4,600 newly-unemployed people in the Swiss Canton of Vaud, it looks at the factors that influence jobseekers' decisions to turn to informal contacts for their job search. The article shows that many unemployed people are not making use of their network because they are unaware of the importance of this method. Second, it presents an impact analysis of an innovative intervention designed to raise awareness of the importance of networks which is tested in a randomized controlled trial setting.

Audit report on the Iowa Water Pollution Control Works Financing Program and the Iowa Drinking Water Facilities Financing Program, joint programs of the Iowa Finance Authority and the Iowa Department of Natural Resources, for the year ended June 30, 2010

Audit report on the Iowa Water Pollution Control Works Financing Program and the Iowa Drinking Water Facilities Financing Program, joint programs of the Iowa Finance Authority and the Iowa Department of Natural Resources, for the year ended June 30, 2010

Etude de l'activation et de l'inactivation pH-dépendantes des canaux ASICs (Acide-Sensing Ion Channels)

RESUME: Etude de l'activation et de l'inactivation pH-dépendantes des canaux ASICs (Acid-Sensing Ion Channels) Benoîte BARGETON, Département de Pharmacologie et de Toxicologie, Université de Lausanne, rue du Bugnon 27, CH-1005 Lausanne, Suisse Les canaux sodiques ASICs (Acid-Sensing Ion Channels) participent à la signalisation neuronale dans les systèmes nerveux périphérique et central. Ces canaux non voltage dépendants sont impliqués dans l'apprentissage, l'expression de la peur, la neurodégénération consécutive à une attaque cérébrale et la douleur. Les bases moléculaires sous-tendant leur activité ne sont pas encore totalement comprises. Ces canaux sont activés par une acidification du milieu extracellulaire et régulés, entre autres, par des ions tels que le Ca2+, le Zn2+ et le CI". La cristallisation de ASIC inactivé a été publiée. Le canal est un trimére de sous-unités identiques ou homologues. Chaque sous-unité a été décrite en analogie à un avant bras, un poignet et une main constituée d'un pouce, d'un doigt, d'une articulation, une boule β et une paume. Nous avons appliqué une approche bioinformatique systématique pour identifier les pH senseurs putatifs de ASICIa. Le rôle des pH senseurs putatifs a été testé par mutagénèse dirigée et des modifications chimiques combinées à une analyse fonctionnelle afin de comprendre comment les variations de ρ H ouvrent ces canaux. Les pH senseurs sont des acides aspartiques et glutamiques éparpillés sur la boucle extracellulaire suggérant que les changements de pH contrôlent l'activation et l'inactivation de ASIC en (dé)protonant ces résidus en divers endroits de la protéine. Par exemple lors de l'activation, la protonation des résidus à l'interface entre le pouce, la boule β et le doigt d'une même sous-unité induit un mouvement du pouce vers la bouie β et le doigt. De même lors de l'inactivation du canal les paumes des trois sous-unités formant une cavité se rapprochent. D'après notre approche bioinformatique, aucune histidine n'est impliquée dans la détection des variations de pH extracellulaire c'est-à-dire qu'aucune histidine ne serait un pH-senseur. Deux histidines de ASIC2a lient le Zn2+ et modifient l'affinité apparente du canal pour les protons. Une seule des deux est conservée parmi tous les ASICs, hASICIa H163. Elle forme un réseau de liaison hydrogène avec ses voisins conservés. L'étude détaillée de ce domaine, Pinterzone, montre son importance dans l'expression fonctionnelle des canaux. La perturbation de ce réseau par l'introduction d'un résidu hydrophobe (cystéine) par mutagénèse dirigée diminue l'expression du canal à la membrane plasmique. La modification des cystéines introduites par des réactifs spécifiques aux groupements sulfhydryle inhibe les canaux mutés en diminuant leur probabilité d'ouverture. Ces travaux décrivent les effets de l'acidification du milieu extracellulaire sur les canaux ASICs. ABSTRACT: Study of pH-dependent activation and inactivation of ASIC channels Benoîte BARGETON, Department of Pharmacology and Toxicology, University of Lausanne, Rue du Bugnon 27, CH-1G05 Lausanne, Switzerland The ASIC (Acid-Sensing Ion Channels) sodium channels are involved in neuronal signaling in the central and peripheral nervous system. These non-voltage-gated channels are involved in learning, the expression of fear, neurodegeneration after ischemia and pain sensation. The molecular bases underlying their activity are not yet fully understood. ASICs are activated by extracellular acidification and regulated, eg by ions such as Ca2+, the Zn2+ and CI". The crystallization of inactivated ASIC has been published. The channel is a trimer of identical or homologous subunits. Each subunit has been described in analogy to a forearm, wrist and hand consisting of a thumb, a finger, a knuckle, a β-ball and a palm. We applied a systematic computational approach to identify putative pH sensor(s) of ASICIa. The role of putative pH sensors has been tested by site-directed mutagenesis and chemical modification combined with functional analysis in order to understand how changes in pH open these channels. The pH sensors are aspartic and glutamic acids distributed throughout the extracellular loop, suggesting that changes in pH control activation and inactivation of ASIC by protonation / deprotonation of many residues in different parts of the protein. During activation the protonation of various residues at the interface between the finger, the thumb and the β-ball induces the movement of the thumb toward the finger and the β-ball. During inactivation of the channel the palms of the three subunits forming a cavity approach each other. No histidine has been shown to be involved in extracellular pH changes detection, i.e. no histidine is a pH- sensor. Two histidines of ASIC2 bind Zn2+ and alter the apparent affinity of channel for protons. Only one of the two His is conserved among all ASICs, hASICIa H163. This residue is part of a network of hydrogen bonding with its conserved neighbors. The detailed study of this area, the interzone, shows its importance in the functional expression of ASICs. Disturbance of this network by the introduction of hydrophobic residues decreases the cell surface channel expression. Chemical modification of the introduced cysteines by thiol reactive compounds inhibits the mutated channels by a reduction of their open probability. These studies describe the effects of extracellular acidification on ASICs. RESUME GRAND PUBLIC: Etude de l'activation et de l'inactivation pH-dépendantes des canaux ASICs (Acid-Sensing Ion Channels) Benoîte BARGETON, Département de Pharmacologie et de Toxicologie, Université de Lausanne, rue du Bugnon 27, CH-1005 Lausanne, Suisse La transmission synaptique est un processus chimique entre deux neurones impliquant des neurotransmetteurs et leurs récepteurs. Un dysfonctionnement de certains types de synapses est à l'origine de beaucoup de troubles nerveux, tels que certaine forme d'épilepsie et de l'attention. Les récepteurs des neurotransmetteurs sont de très bonnes cibles thérapeutiques dans de nombreuses neuropathologies. Les canaux ASICs sont impliqués dans la neurodégénération consécutive à une attaque cérébrale et les bloquer pourraient permettre aux patients d'avoir moins de séquelles. Les canaux ASICs sont des détecteurs de l'acidité qui apparaît lors de situations pathologiques comme l'ischémie et l'inflammation. Ces canaux sont également impliqués dans des douleurs. Cibler spécifiquement ces canaux permettrait d'avoir de nouveaux outils thérapeutiques car à l'heure actuelle l'inhibiteur de choix, l'amiloride, bloque beaucoup d'autres canaux empêchant son utilisation pour bloquer les ASICs. C'est pourquoi il faut connaître et comprendre les bases moléculaires du fonctionnement de ces récepteurs. Les ASICs formés de trois sous-unités détectent les variations de l'acidité puis s'ouvrent transitoirement pour laisser entrer des ions chargés positivement dans la cellule ce qui active la signalisation neuronale. Afin de comprendre les bases moléculaires de l'activité des ASICs nous avons déterminé les sites de liaison des protons (pH-senseurs), ligands naturels des ASICs et décrit une zone importante pour l'expression fonctionnelle de ces canaux. Grâce à une validation systématique de résultats obtenus en collaboration avec l'Institut Suisse de Bioinformatique, nous avons décrit les pH-senseurs de ASICIa. Ces résultats, combinés à ceux d'autres groupes de recherche, nous ont permis de mieux comprendre comment les ASICs sont ouverts par une acidification du milieu extracellulaire. Une seconde étude souligne le rôle structural crucial d'une région conservée parmi tous les canaux ASICs : y toucher c'est diminuer l'activité de la protéine. Ce domaine permet l'harmonisation des changements dus à l'acidification du milieu extracellulaire au sein d'une même sous-unité c'est-à-dire qu'elle participe à l'induction de l'inactivation due à l'activation du canal Cette étude décrit donc quelle région de la protéine atteindre pour la bloquer efficacement en faisant une cible thérapeutique de choix.

Audit report on the Xenia Rural Water District for the year ended December 31, 2010

Audit report on the Xenia Rural Water District for the year ended December 31, 2010

Transport of a biocontrol Pseudomonas fluorescens through 2.5-m deep outdoor lysimeters and survival in the effluent water

Application of wild-type or genetically-modified bacteria to the soil environment entails the risk of dissemination of these organisms to the groundwater. To measure vertical transport of bacteria under natural climatic conditions, Pseudomonas fluorescens strain CHA0 was released together with bromide as a mobile tracer at the surface of large outdoor lysimeters. Two experiments, one starting in autumn 1993 and the other in spring 1994 were performed. Shortly after a heavy rainfall in late spring 1994, the released bacteria were detected for the first time in effluent water from the 2.5-m-deep lysimeters in both experiments, i.e. 210 d and 21 d, respectively, after inoculation. Only a 10−9 to 10−8 fraction of the inoculum was recovered as culturable cells in the effluent water, but a larger fraction of the CHA0 cells was in a non-culturable state as detected with immunofluorescence microscopy. As much as 50% of the mobile tracer percolated through the lysimeters, indicating that, compared with bromide, bacterial cells were retained in soil. In the second part of this study, persistence of CHA0 in groundwater microcosms consisting of lysimeter effluent water was studied for 380 d. Survival of the inoculant as culturable cells was better under anaerobic than under aerobic conditions. However, a large fraction of the cells became non-culturable in both cases. When the experiment was performed with filter-sterilized effluent water, the total count of introduced bacteria did not decline with time. In conclusion, the biocontrol strain was transported in low numbers to a potential groundwater level under natural climatic conditions, but could persist for an extended period in groundwater microcosms.

Soil water dynamics related to the degree of compaction of two brazilian oxisols under no-tillage

Soil water properties are related to crop growth and environmental aspects and are influenced by the degree of soil compaction. The objective of this study was to determine the water infiltration and hydraulic conductivity of saturated soil under field conditions in terms of the compaction degree of two Oxisols under a no-tillage (NT). Two commercial fields were studied in the state of Rio Grande do Sul, Brazil: one a Haplortox after 14 years under NT; the other a Hapludox after seven years under NT. Maps (50 x 30 m) of the levels of mechanical penetration resistance (PR) were drawn based on the kriging method, differentiating three compaction degrees (CD): high, intermediate and low. In each CD area, the infiltration rate (initial and steady-state) and cumulative water infiltration were measured using concentric rings, with six replications, and the saturated hydraulic conductivity (K(θs)) was determined using the Guelph permeameter. Statistical evaluation was performed based on a randomized design, using the least significant difference (LSD) test and regression analysis. The steady-state infiltration rate was not influenced by the compaction degree, with mean values of 3 and 0.39 cm h-1 in the Haplortox and the Hapludox, respectively. In the Haplortox, saturated soil hydraulic conductivity was 26.76 cm h-1 at a low CD and 9.18 cm h-1 at a high CD, whereas in the Hapludox, this value was 5.16 cm h-1 and 1.19 cm h-1 for the low and high CD, respectively. The compaction degree did not affect the initial and steady-state water infiltration rate, nor the cumulative water infiltration for either soil type, although the values were higher for the Haplortox than the Hapludox.

Impact of precipitation on the water table level of different ombrotrophic raised bog complexes, central Estonia

Sadannan vaikutus vedenpinnan tasoon kohosuolla

Compressibility of Oxisol aggregates under no-till in response to soil water potential

The system of no-till sowing stands out as being a technology that suits the objectives of more rational use of the soil and greater protection against the erosion. However, through till, any of it, occurs modifications of the soil's structure. This current work aims to study the influence of the energy state of the water and of the organic matter on the mechanism of compaction of Red Oxisol under no-till management system. Humid and non-deformed sample were collected in horizon AP of two agricultural areas under no-till, with and without rotation of cultures. In the laboratory, these samples were broken into fragments and sifted to obtain aggregates of 4 to 5 mm sized, which were placed in equilibrium under four matrix potentials. Thereafter, they were exposed to uni-dimensional compression with pressures varying from 32 to 1,000 kPa. The results in such a way show that the highest compressibility of aggregates both for the tilling with rotation of cultures as for the tilling without rotation of cultures, occurred for matrix potential -32 kPa (humidity of 0.29-0.32 kg kg-1, respectively), while the minor occurred for the potentials of -1 and -1,000 kPa (humidity of 0.35 and 0.27 kg kg-1, respectively), indicating that this soil should not be worked with humidity ranging around 0.29 to 0.32 kg kg-1 and the highest reduction of volume of aggregates was obtained for the mechanical pressures lower than 600 inferior kPa, indicating that these soils showed to be very influenced by compression, when exposed to mechanical work. Also, the aggregates of soil under no-till and rotation of crops presented higher sensitivity to the compression than the aggregates of soil under no-till and without rotation of crops, possibly for having better structural conditions given to a higher content of organic matter.

Estimation of water retention and availability in soils of Rio Grande do Sul

Dispersed information on water retention and availability in soils may be compiled in databases to generate pedotransfer functions. The objectives of this study were: to generate pedotransfer functions to estimate soil water retention based on easily measurable soil properties; to evaluate the efficiency of existing pedotransfer functions for different geographical regions for the estimation of water retention in soils of Rio Grande do Sul (RS); and to estimate plant-available water capacity based on soil particle-size distribution. Two databases were set up for soil properties, including water retention: one based on literature data (725 entries) and the other with soil data from an irrigation scheduling and management system (239 entries). From the literature database, pedotransfer functions were generated, nine pedofunctions available in the literature were evaluated and the plant-available water capacity was calculated. The coefficient of determination of some pedotransfer functions ranged from 0.56 to 0.66. Pedotransfer functions generated based on soils from other regions were not appropriate for estimating the water retention for RS soils. The plant-available water content varied with soil texture classes, from 0.089 kg kg-1 for the sand class to 0.191 kg kg-1 for the silty clay class. These variations were more related to sand and silt than to clay content. The soils with a greater silt/clay ratio, which were less weathered and with a greater quantity of smectite clay minerals, had high water retention and plant-available water capacity.

Effect of dietary crude protein and energy content on nitrogen utilisation, water intake and urinary output in growing pigs

Selostus: Rehun valkuais- ja energiapitoisuuden vaikutus sikojen typen hyväksikäyttöön, veden kulutukseen ja virtsan eritykseen

Differential expression and hypoxic regulation of adenosine receptors and TRPC channels in the developing heart.

Objectives: To characterize the modifications of gene expression of adenosine receptors (AR), TRPC channels, HIF-1α and iNOS during the early cardiogenesis in response to chronic hypoxia exposure. Methods: 4-day-old chick embryos were subjected in ovo to 6H, 12H and 24H of hypoxia (10% O2). The mRNA expression was quantified by RT-qPCR. Results: The targeted genes were found to be expressed at mRNA level with a differential expression pattern within the heart. Hypoxia has no significant effect on mRNA expression of ARs, TRPCs channels and iNOS within the heart. By contrast, HIF-1α mRNA expression shows a tendency to be down-regulated by hypoxia. Conclusion: These results suggest that an intrauterine oxygen lack does not significantly affect expression of genes involved in adenosine signaling and in calcium handling by store operated channels (TRPC).