Evidence for Effective Multiple K+-Current Inhibitions by Tolvaptan, a Non-peptide Antagonist of Vasopressin V2 Receptor

Tolvaptan (TLV), an oral non-peptide antagonist of vasopressin V2 receptor, has been increasingly used for managements in patients with hyponatremia and/or syndrome of inappropriate antidiuretic hormone secretion. However, none of the studies have thus far been investigated with regard to its possible perturbations on membrane ion currents in endocrine or neuroendocrine cells. In our electrophysiological study, the whole-cell current recordings showed that the presence of TLV effectively and differentially suppressed the amplitude of delayed rectifier K+ (IK(DR)) and M-type K+ current (IK(M)) in pituitary GH3 cells with an IC50 value of 6.42 and 1.91 μM, respectively. This compound was also capable of shifting the steady-state activation curve of IK(M) to less depolarized potential without any appreciable change in the gating charge of this current. TLV at a concentration greater than 10 μM also suppressed the amplitude of erg-mediated K+ current or the activity of large-conductance Ca2+-activated K+ channels; however, this compound failed to alter the amplitude of hyperpolarization-activated cation current in GH3 cells. In vasopressin-preincubated GH3 cells, TLV-mediated suppression of IK(M) remained little altered. Under current-clamp condition, we also observed that addition of TLV increased the firing of spontaneous action potentials in GH3 cells and further addition of flupirtine could reverse TLV-mediated elevation of the firing. In Madin-Darby canine kidney (MDCK) cells, the K+ current elicited by long ramp pulse was also effectively subject to inhibition by this compound. Findings from the present study were thus stated as saying that the suppression by TLV of multiple type K+ currents could be direct and independent of its antagonism of vasopressin V2 receptors. Our study also reveals an important aspect that should be considered when assessing aquaretic effect of TLV or its structurally similar compounds

Apparent soil electrical conductivity as an indicator of paddy soil productivity (Konduktiviti elektrik berkelihatan sebagai petunjuk produktiviti tanah padi)

Abstract Paddy soils are naturally heterogeneous in terms of their physico-chemical properties which influence rice productivity. Currently, uniform application of agricultural fertilizers for the entire field is not efficient and could result in either insufficient or excess nutrient supply. Good agricultural practices can be achieved if soil and nutrient variations within a farm are considered, and a soil-yield interrelationship is established. Simple, rapid and accurate methods to characterize these variations are needed. This study was conducted in MARDI Seberang Perai Research Station located at the northern part of Peninsular Malaysia. Soil samples were collected at regular grid spacing from the upper (0-20 cm) and lower (30 -50 cm) soil layers. These samples were analysed for their soil texture and chemical properties. Crop cutting test yields were taken at the same soil sampling locations. Geo-referenced apparent electrical conductivity (EC a ) measurements were obtained by using Veris 3100 cart equipped with a data logger and a differential global positioning system (DGPS). The relationship between grain yield and EC a was examined for three crop seasons in scatter plots. A boundary line using log-normal function was fitted to the upper edge of the data in the scatter plots. Significant relationships between potential grain yield and EC a were found with r 2 >0.58. The significant correlations of temporal soil EC a and measurements implied that soil EC a within field do not tend to change significantly over time. Comparison of potential yield (Y po ) and observed yield (Y ob ) led to classification of farm areas into different management zones and allows for discriminate management practices particularly to low yield areas due to less than ideal field conditions

A multidimensional platform for the purification of non-coding RNA species

A renewed interest in non-coding RNA (ncRNA) has led to the discovery of novel RNA species and post-transcriptional ribonucleoside modifications, and an emerging appreciation for the role of ncRNA in RNA epigenetics. Although much can be learned by amplification-based analysis of ncRNA sequence and quantity, there is a significant need for direct analysis of RNA, which has led to numerous methods for purification of specific ncRNA molecules. However, no single method allows purification of the full range of cellular ncRNA species. To this end, we developed a multidimensional chromatographic platform to resolve, isolate and quantify all canonical ncRNAs in a single sample of cells or tissue, as well as novel ncRNA species. The applicability of the platform is demonstrated in analyses of ncRNA from bacteria, human cells and plasmodium-infected reticulocytes, as well as a viral RNA genome. Among the many potential applications of this platform are a system-level analysis of the dozens of modified ribonucleosides in ncRNA, characterization of novel long ncRNA species, enhanced detection of rare transcript variants and analysis of viral genomes.Singapore-MIT Alliance for Research and TechnologyNational Institute of Environmental Health Sciences (ES017010)National Institute of Environmental Health Sciences (ES002109

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions

Spatial Apparent Electrical Conductivity of Paddy Soil as an Indicator of Rice Productivity

Paddy soils are naturally heterogeneous in terms of their physico-chemical properties which influence rice productivity. Currently, uniform application of agricultural fertilizers for the entire field is not efficient and could result in either insufficient or excess nutrient supply. Good agricultural practices can be achieved if soil and nutrient variations within a farm are considered, and a soil-yield interrelationship is established. Simple, rapid and accurate methods to characterize variation in soil properties are needed. This study was conducted on two different plots within Malaysia Agricultural Development and Research Institute (MARDI) Research Station located at the northern part of Peninsular Malaysia. One of the plots is a single large contiguous plot of 9-ha, free of farm encumbrances and the other is equipped with subsurface drainage facilities. Soil samples were collected at regular grid spacing from the upper (0-20 cm) and lower (30-50 cm) soil layers respectively. These samples were analyzed for their soil texture and chemical properties. Crop cutting test yields were taken at the same soil sampling locations. Geo-referenced apparent electrical conductivity (ECa) measurements were obtained by using Veris 3100 cart equipped with a data logger and a differential global positioning system. Soil ECa mapping is a simple and rapid tool that can be used to provide estimate of the within field soil differences associated with soil properties which is a measure of field conditions and soil suitability for crop growth and yield. The significant correlations of soil ECa and mapping date showed that the patterns of soil ECa within a field do not tend to change significantly over time. Generally, once an ECa map has been made, it will remain relatively accurate unless significant soil movements occur. The correlations between shallow and deep soil ECa were found to be significant too. And significant relationships between potential grain yield and ECa were found using a form of boundary line analysis in scatter plots with r2 > 0.58 in all the six investigations in three crop-seasons. The log-normal function chosen to fit the boundary datasets was flexible in representing various responses combination to ECa values and could correctly indicated significant higher yield can be obtained from areas with high predicted potential yield. Comparison of Ypo and Yob can delineate farm areas into different management zones and allows for discriminate management practices particularly to low yield areas due to less then ideal field conditions, thus resulting good agricultural practices. These practices could result in less wastage of applied inputs, less pollution, lower input costs and most important higher return

Characterisation of multicrystalline solar cells

The evaluation and assessment of the performance of photovoltaic (PV) cells in terms of measurable parameters requires the measurement of the current as a function of voltage, temperature, intensity, wind speed and spectrum. Mo st noticeable of all these parameters is the PV conversion efficiency η, defined as the maximum electrical power Pmax produced by the PV cell divided by the incident photon power P in which is measured with respect to standard test conditions (STC). These conditions refer to the spectrum (AM 1.5), solar radiation intensity (1000 Wm-2), cell temperature (25 ±2oC) and wind speed (2 mph). Tests under STC are carried out in the laboratory at a controlled environment. There have been several studies that analyze uncertainties in the laboratory measurement of solar cell efficiencies using different solar simulators and their transference to operational situations. Our preliminary results demonstratethat the short circuit current (ISC) of the solar cell decreases when irradiance is less than 1000 Wm-2 irrespective of the working temperature of the cell

Characterisation of multicrystalline solar cells

The evaluation and assessment of the performance of photovoltaic (PV) cells in terms of measurable parameters requires the measurement of the current as a function of voltage, temperature, intensity, wind speed and spectrum. Mo st noticeable of all these parameters is the PV conversion efficiency η, defined as the maximum electrical power Pmax produced by the PV cell divided by the incident photon power P in which is measured with respect to standard test conditions (STC). These conditions refer to the spectrum (AM 1.5), solar radiation intensity (1000 Wm-2), cell temperature (25 ±2oC) and wind speed (2 mph). Tests under STC are carried out in the laboratory at a controlled environment. There have been several studies that analyze uncertainties in the laboratory measurement of solar cell efficiencies using different solar simulators and their transference to operational situations. Our preliminary results demonstratethat the short circuit current (ISC) of the solar cell decreases when irradiance is less than 1000 Wm-2 irrespective of the working temperature of the cell