Significant Increase In Ca2 Research Articles

Dysregulation of Norepinephrine Release in the Absence of Functional Synaptotagmin 7.

Synaptotagmin 7 (Syt7) is expressed in cardiac sympathetic nerve terminals where norepinephrine (NE) is released in both Ca(2+)-dependent exocytosis and Ca(2+)-independent norepinephrine transporter (NET)-mediated overflow. The role of Syt7 in the regulation of NE release from cardiac sympathetic nerve terminals is tested by employing a Syt7 knock-in mouse line that expresses a non-functional mutant form of Syt7. In cardiac sympathetic nerve terminals prepared from these Syt7 knock-in mice, the Ca(2+)-dependent component of NE release was diminished. However, these terminals displayed upregulated function of NET (∼130% of controls) and a significant increase in Ca(2+)-independent NE overflow (∼140% of controls), which is greater than the Ca(2+)-dependent component of NE exocytosis occurring in wild-type controls. Consistent with a significant increase in NE overflow, the Syt7 knock-in mice showed significantly higher blood pressures compared to those of littermate wild-type and heterozygous mice. Our results indicate that the lack of functional Syt7 dysregulates NE release from cardiac sympathetic nerve terminals.

Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca(2+)-ATPase.

The occurrence of Hofmeister (specific ion) effects in various membrane-related physiological processes is well documented. For example the effect of anions on the transport activity of the ion pump Na+, K+-ATPase has been investigated. Here we report on specific anion effects on the ATP-dependent Ca2+ translocation by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Current measurements following ATP concentration jumps on SERCA-containing vesicles adsorbed on solid supported membranes were carried out in the presence of different potassium salts. We found that monovalent anions strongly interfere with ATP-induced Ca2+ translocation by SERCA, according to their increasing chaotropicity in the Hofmeister series. On the contrary, a significant increase in Ca2+ translocation was observed in the presence of sulphate. We suggest that the anions can affect the conformational transition between the phosphorylated intermediates E1P and E2P of the SERCA cycle. In particular, the stabilization of the E1P conformation by chaotropic anions seems to be related to their adsorption at the enzyme/water and/or at the membrane/water interface, while the more kosmotropic species affect SERCA conformation and functionality by modifying the hydration layers of the enzyme.

Lycopene protects against atrazine-induced hepatic ionic homeostasis disturbance by modulating ion-transporting ATPases

The aim of this study was to evaluate the possible chemoprotective role of lycopene (LYC) against atrazine (ATR)-induced ionic disorder and hepatotoxicity in mice. Male kunming mice were treated with LYC (5mg/kg) and/or ATR (50mg/kg or 200mg/kg) by lavage administration for 21days. Ionic disorder was assessed by determining the Na+, K+ and Ca2+ content and the alteration in ATP enzymes (ATPases) including Na+-K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and Ca2+-Mg2+-ATPase and the mRNA levels of ATPase's subunits in liver. ATR caused the increases of alanine aminotransferase and aspartate aminotransferase activities and histological changes. LYC pretreatment significantly protected liver against ATR-caused alternation. The significant effect of ATR and LYC on the K+ and Mg2+ content in liver was not observed, but ATR increased hepatic Na+-K+-ATPase activity and decreased Mg2+-ATPase and Ca2+-Mg2+-ATPase activity. The mRNA expressions of Na+-K+-ATPase subunits were regulated significantly by ATR. A significant increase of Ca2+ content and seven down-regulated mRNA expressions of Ca2+-ATPase subunits and a decrease of Ca2+-ATPase activity were observed in the ATR-treated mice. Notably, LYC modulated these ATR-induced alterations of ATPase activity and mRNA expression of their subunits. These results suggest that ATR presents hepatotoxicity via regulating hepatic ATPase's activities and their subunit transcriptions and inducing ionic disorder. LYC protects liver against ATR-induced hepatotoxicity, significantly. LYC modulated hepatic ionic homeostasis disturbance via regulation of ATPase activities and their subunits' (1a1, 1b3, 1b4 and 2b4) transcriptions. In summary, these effects play a critical role of LYC-mediated chemoprevention against ATR-induced hepatotoxicity.

Real-time Recording of Cytosolic Calcium Levels in Arabidopsis thaliana Cell Cultures during Parabolic Flights

In plants, like in other organisms, calcium (Ca2+) is an important second messenger which participates in the conversion of environmental signals into molecular responses. There is increasing evidence, that sensing of changes in gravitation or reorientation of tissues is an example for such signaling cascades in which Ca2+ is involved. In order to determine g-dependent changes in the cytosolic calcium (Ca $^{2+}_{\text {cyt}})$ concentration of plant cells, semisolid transgenic callus cell cultures of Arabidopsis thaliana (A.t.), expressing the calcium sensor YC3.6 (cameleon), were exposed to g-forces between 1.8g and μg during parabolic flights. Using such cells, intracellular calcium transients can be monitored by FRET in vivo and in real-time. Interestingly we observed a slight decrease of the Ca $^{2+}_{\text {cyt}}$ level during the hypergravity phases of a parabola but a significant increase of the Ca $^{2+}_{\text {cyt}}$ concentration during microgravity. Application of known Ca2+ inhibitors and antagonists yielded the following effects: nifedipine (Ca2+ channel blocker) showed no effect, whereas LaCl3, GdCl3 (both inhibitors of uptake at the plasma membrane), DPI (inhibitor of NADP oxidase), and DMSO (solvent) diminished the gravity-alteration-related Ca $^{2+}_{\text {cyt}}$ response. EGTA (binding of Ca2+) and eosin yellow (inhibitor of a plasma membrane-located Ca2+ pump) suppressed the respective Ca $^{2+}_{\text {cyt}}$ changes entirely. We thus conclude that the significant increase in Ca $^{2+}_{\text {cyt}}$ under microgravity is largely due to extracellular Ca2+ sources.

Improving chemical properties of a highly weathered soil using finely ground basalt rocks

Chemical property degradation of Oxisols (highly weathered soils) is revealed by very low cation exchange capacity and base cations but high Al saturation. The objective of this study was to increase cation exchange capacity and base cations and to alleviate Al toxicity of a highly weathered soil using finely ground basalt rocks. The topsoil and subsoil representing the natural and severely eroded conditions, respectively, were incubated with various rates (up to 80tha−1) of finely ground basalt (<50μm) under ambient laboratory conditions for 24months. The soils and solution were sampled and analyzed periodically. Changes in soil surface charges were assessed by measuring point of zero charge (PZC) to account for variable charge generation and the point of zero net charge (PZNC) to account for all charge generations (variable and permanent charges). The soil solution was sampled using soil moisture samplers to observe cations released from basalt during each incubation period. Results showed that incubation of an Oxisol with finely ground basalt decreased PZC from 3.9 to 3.5 for the topsoil and from 3.9 to 3.7 for the subsoil. Corresponding values for PZNC measurements decreased from 3.05 to 2.52 for the topsoil and from 3.60 to 2.55 for subsoil. The decrease in PZC and PZNC values showed that basalt application was able to increase soil surface negative charge, while in turn increasing soil cation exchange capacity. At a given similar equilibrium pH value, increasing basalt rates showed an increased net negative charge (NetC) from 0.0–6.3 to 3.2–8.7 cmolc kg−1, depending on basalt rates. This indicates that each increment of basalt rates generated “new negative sites” on soil surfaces to retain cations. At natural soil pH representing field conditions, the NetC sharply increased from 1.5 to 10.1 cmolc kg−1 after basalt application. The higher NetC values for the natural condition than the given equilibrium pH values were owing to the higher soil pH values in the former. Interestingly, the total negative charge (CECT) values were comparable to the negative charge occupied by base cations (CECB) at basalt incubation rates of≥10tha−1, indicating that base cations released from basalt successfully displaced acidic cations (e.g. toxic Al) on the soil exchange complexes. Cations released from basalt were revealed by the significant increases in Ca, Mg, K and Na both in the forms of exchangeable cations (measured from the solid phase) and soluble cations (measured from the soil solution), with concomitant reduction in Al and Mn contents. Hence, finely ground basalt is a promising natural material that can be used to restore negative charge and base cations and suppress Al and Mn contents of highly weathered soils, which in turn, have a great impact on preventing cation leaching, increasing soil nutrient availability and reducing elemental toxicities.

Hypericum caprifoliatum and Hypericum connatum affect human trophoblast-like cells differentiation and Ca2+ influx

To study the effect of crude methanol and n-hexane extracts of Hypericum connatum (H. connatum) and Hypericum caprifoliatum on trophoblast-like cells. BeWo and JEG-3 trophoblast-like cells were submitted to different extract concentrations (1, 5, 10 and 15 µg/mL) and evaluated in relation to cell viability and in vitro trophoblast differentiation and function. Cell viability was evaluated using WST-1 reagent. Differentiation was measured by luciferase production, hCG production/release, and mitogen-activated protein kinase signaling pathway activation. The function of the trophoblast-like cells was measured by (45)Ca(2+) influx evaluation. The results showed a decrease in cell viability/proliferation. Both plants and different extracts induced a significant decrease in hCG production/release and luciferase production. H. connatum did not cause mitogen-activated protein kinase signaling pathway disturbance; however, Hypericum caprifoliatum n-hexane extract at 15 µg/mL inhibited extracellular signal-regulated kinase 1/2 activation. The significant increase in Ca(2+) influx by JEG-3 cells was seen after short and long incubation times with H. connatum methanolic extract at 15 µg/mL. The results indicated that these two Hypericum species extracts can interfere on trophoblast differentiation and Ca(2+) influx, according to their molecular diversity. Although in vivo experiments are necessary to establish their action on placental formation and function, this study suggests that attention must be paid to the potential toxic effect of these plants.

Effect of pomegranate peel supplementation on nutritional, organoleptic and stability properties of cookies

The present study aims at highlighting the nutritive potential of pomegranate peel and its possible utilization as an ingredient of choice to nutritionally enrich cookies. Biochemical composition and free radical scavenging features of pomegranate peel powder (PoP) and PoP supplemented cookies were measured. PoP supplementation significantly (p < 0.05) improved dietary fibers (0.32–1.96 g/100 g), total phenols (90.7–161.9 mg GAE/100 g) and inorganic residues (0.53–0.76 g/100 g) of cookies. Similarly, significant increase in Ca, K, Fe and Zn levels was noted in supplemented cookies. Almost 50% 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was recorded in cookies carrying highest concentration of PoP and phenolic contents. PoP phenolics of supplemented cookies were shown to reduce oxidative degradation during four months storage. Present study suggests PoP supplementation in baked products as a potential source of micro and macronutrients. Application of PoP in ready to serve foods seems to be a potential disease preventive and ameliorative approach in tandem with its preservation and nutritional enhancement features.

Do Cardiac Actin Mutations Lead to Altered Muscle Contractility?

The hypothesis that increased heart muscle contractility leads to HCM and reduced contractility leads to DCM is based mainly on studies on myosin motor proteins. This hypothesis predicts that a change in cardiac actin (ACTC) may impact muscle contractility. To test this prediction, we determined the interactions between myosin and 8 of 16 ACTC mutant proteins that are known to cause hypertrophic or dilated cardiomyopathy. R312H showed a decreased actin-activated S1 ATPase rate (13.1±0.63 μM/min) compared to WT (15.3±1.58 μM/min), whereas the rate with E99K was significantly higher (20.1±1.46μM/min). In vitro motility assays were performed with varying ATP concentrations. E99K exhibited increased KM (0.086±0.02 μM) compared to WT (0.068±0.02 μM). E99K demonstrated a significantly decreased Vmax (1.93±0.1 μm/sec) compared to WT (3.31±0.12 μm/sec). In contrast, M305 had a similar KM (0.088±0.01 μm/sec) to E99K, but its Vmax (3.39±0.11μm/sec) was similar to WT. Based on a 5 nm myosin step size, we calculated a duty ratio of about 0.04 for WT and most mutant actins; however, the duty ratio was twice as high for E99K. With thin-filament extracted and reconstituted muscle fibers with E99K, a slight, but significant increase in Ca2+sensitivity (ΔpCa=0.11±0.04) was observed; consequently tension was slightly larger than that of WT for pCa ranging 5.6-6.0, without changing maximum tension at pCa 4.66. These experiments suggest that the primary change with the E99K actin mutant is enhanced ATP usage and increased tension at partial activation, which lead to HCM.

Study on effect of combination of Epimedii Folium and Ligustri Lucidi Fructus on osteoporosis rats induced by retinoic acid

To explore the effect of combination of Epimedii Folium and Ligustri Lucidi Fructus on osteoporosis rats induced by retinoic acid. Sixty three-month-old male Wistar rats were randomly divided into the normal control group, the model group, the Epimedii Folium group, the Ligustri Lucidi Fructus group, the combination group of Epimedii Folium and Ligustri Lucidi Fructus and the raloxifene group. The osteoporosis model was established through oral administration with retinoic acid for two weeks. Meanwhile, all of treatment groups were administered with corresponding drugs for three weeks. The contents of serum calcium (Ca), phosphorus (P), alkaline phosphatase (AKP) and tartrate-resistant acid phosphatase (StrACP) were detected, and the pathomorphological changes of femurs were observed. The model control group showed much lower contents of serum Ca and P than the normal control group, but with significantly higher AKP and StrACP activity than the normal control group. The femoral head area showed reduced, narrow and sparse trabecular bones, with typical osteoporosis-like changes. Compared with the model control group, all of treated groups showed significant increase in Ca and P contents in serum, and down-regulate AKP and StrACP levels, while trabecular bones became more and wider, and densely interweaved as a reticular formation. Among them, the combination group showed the most significant effect. Epimedii Folium and Ligustri Lucidi Fructus could effectively correct the abnormal bone metabolism and improve pathological conditions of bone tissues, so as to show the anti-osteoporosis effect. The combined application of the two drugs showed a better efficacy.

Examination of Calcium-Binding Protein Expression in the Inner Ear of Wild-Type, Heterozygous and Homozygous Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP)-Knockout Mice in Kanamycin-Induced Ototoxicity

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with diverse biological effects. It also occurs and exerts protective effects in sensory organs; however, little is known about its effects in the auditory system. Recently, we have shown that PACAP protects cochlear cells against oxidative-stress-induced apoptosis and homozygous PACAP-deficient animals show stronger expression of Ca(2+)-binding proteins in the hair cells of the inner ear, but there are no data about the consequences of the lack of endogenous PACAP in different ototoxic insults such as aminoglycoside-induced toxicity. In this study, we examined the effect of kanamycin treatment on Ca(2+)-binding protein expression in hair cells of wild-type, heterozygous and homozygous PACAP-deficient mice. We treated 5-day-old mice with kanamycin, and 2days later, we examined the Ca(2+)-binding protein expression of the hair cells with immunohistochemistry. We found stronger expression of Ca(2+)-binding proteins in the hair cells of control heterozygous and homozygous PACAP-deficient mice compared with wild-type animals. Kanamycin induced a significant increase in Ca(2+)-binding protein expression in wild-type and heterozygous PACAP-deficient mice, but the baseline higher expression in homozygous PACAP-deficient mice did not show further changes after the treatment. Elevated endolymphatic Ca(2+) is deleterious for the cochlear function, against which the high concentration of Ca(2+)-buffers in hair cells may protect. Meanwhile, the increased immunoreactivity of Ca(2+)-binding proteins in the absence of PACAP provide further evidence for the important protective role of PACAP in ototoxicity, but further investigations are necessary to examine the exact role of endogenous PACAP in ototoxic insults.

Abstract 153: Angiotensin II-induced Hypertension Alters Endothelial CaMKII

The endothelial dysfunction associated with arterial hypertension is characterized by a Ca2+ dyshomeostasis resulting in an alteration of the delicate balance between reactive oxygen species (ROS) and nitric oxide (NO). However, the underlying mechanisms remain controversial. It has been recently suggested that CaMKII, a Ca2+-calmodulin dependent kinase plays an important role in cardiovascular diseases such as diabetes-associated hypertension. Paradoxically, CaMKII also modulates eNOS expression and activity, and is thereby involved in the regulation of endothelial function. Indeed, acting as a Ca2+ sensor, CaMKII has the unique ability to integrate oscillatory Ca2+ signals into specific outcomes. We recently provided the first evidence that endothelial CaMKII is activated by a local Ca2+ signal, the Ca2+ pulsars, localized within myoendothelial projections (MEP), and results in an increased NO production. The characterization of this novel endothelial CaMKII signalling pathway in pathophysiological conditions will strengthen our understanding of endothelial dysfunction associated with hypertension. This study aimed at the characterization of the impact of AngII-induced hypertension on the correlation between endothelial Ca2+pulsars and CaMKII in microvasculature. Real-time confocal imaging showed that acute exposure to AngII (10 μM) increases both ROS intracellular levels (52%) and Ca2+ pulsars frequency (35%). Exposure to lower AngII levels (100 nM) only increased Ca2+ pulsars frequency (49%). However, CaMKIIα and β clustering (and activation) within MEP was observed at both AngII levels. Acute AngII also stimulated NO production (42%), an increase blunted by CaMKII inhibition with KN-93 (17%). Although a significant increase in Ca2+ pulsars frequency was observed (147%) in AngII-hypertensive mice, an AngII-induce increased in endothelial ROS levels was recorded independently of blood pressure levels. Recruitment of CaMKIIα and β at the MEP by chronic AngII was also increased regardless of blood pressure (60% and 43%). Our finding strongly suggests that AngII stimulates CaMKII through both ROS and Ca2+ pulsars . This study consolidates our understanding of CaMKII as a key regulatory component of endothelial function.

Differential regulation of cardiac excitation–contraction coupling by cAMP phosphodiesterase subtypes

Multiple phosphodiesterases (PDEs) hydrolyze cAMP in cardiomyocytes, but the functional significance of this diversity is not well understood. Our goal here was to characterize the involvement of three different PDEs (PDE2-4) in cardiac excitation-contraction coupling (ECC). Sarcomere shortening and Ca(2+) transients were recorded simultaneously in adult rat ventricular myocytes and ECC protein phosphorylation by PKA was determined by western blot analysis. Under basal conditions, selective inhibition of PDE2 or PDE3 induced a small but significant increase in Ca(2+) transients, sarcomere shortening, and troponin I phosphorylation, whereas PDE4 inhibition had no effect. PDE3 inhibition, but not PDE2 or PDE4, increased phospholamban phosphorylation. Inhibition of either PDE2, 3, or 4 increased phosphorylation of the myosin-binding protein C, but neither had an effect on L-type Ca(2+) channel or ryanodine receptor phosphorylation. Dual inhibition of PDE2 and PDE3 or PDE2 and PDE4 further increased ECC compared with individual PDE inhibition, but the most potent combination was obtained when inhibiting simultaneously PDE3 and PDE4. This combination also induced a synergistic induction of ECC protein phosphorylation. Submaximal β-adrenergic receptor stimulation increased ECC, and this effect was potentiated by individual PDE inhibition with the rank order of potency PDE4 = PDE3 > PDE2. Identical results were obtained on ECC protein phosphorylation. Our results demonstrate that PDE2, PDE3, and PDE4 differentially regulate ECC in adult cardiomyocytes. PDE2 and PDE3 play a more prominent role than PDE4 in regulating basal cardiac contraction and Ca(2+) transients. However, PDE4 becomes determinant when cAMP levels are elevated, for instance, upon β-adrenergic stimulation or PDE3 inhibition.

Functional subcellular distribution of β1 - and β2 -adrenergic receptors in rat ventricular cardiac myocytes

β-adrenergic stimulation is a key regulator of cardiac function. The localization of major cardiac adrenergic receptors (β1 and β2) has been investigated using biochemical and biophysical approaches and has led to contradictory results. This study investigates the functional subcellular localization of β1- and β2-adrenergic receptors in rat ventricular myocytes using a physiological approach. Ventricular myocytes were isolated from the hearts of rat and detubulated using formamide. Physiological cardiac function was measured as Ca2+ transient using Fura-2-AM and cell shortening. Selective activation of β1- and β2-adrenergic receptors was induced with isoproterenol (0.1 μmol/L) and ICI-118,551 (0.1 μmol/L); and with salbutamol (10 μmol/L) and atenolol (1 μmol/L), respectively. β1- and β2-adrenergic stimulations induced a significant increase in Ca2+ transient amplitude and cell shortening in intact rat ventricular myocytes (i.e., surface sarcolemma and t-tubules) and in detubulated cells (depleted from t-tubules, surface sarcolemma only). Both β1- and β2-adrenergic receptors stimulation caused a greater effect on Ca2+ transient and cell shortening in detubulated myocytes than in control myocytes. Quantitative analysis indicates that β1-adrenergic stimulation is ∼3 times more effective at surface sarcolemma compared to t-tubules, whereas β2- adrenergic stimulation occurs almost exclusively at surface sarcolemma (∼100 times more effective). These physiological data demonstrate that in rat ventricular myocytes, β1-adrenergic receptors are functionally present at surface sarcolemma and t-tubules, while β2-adrenergic receptors stimulation occurs only at surface sarcolemma of cardiac cells.

Biochemical, physiological and gene expression analysis reveals sex‐specific differences in Populus tomentosa floral development

The productivity, distribution and population structure of poplar are affected by temperature transitions. Poplar floral buds develop in a fluctuating environment and the molecular basis of temperature-dependent flowering regulation has been extensively studied, but little is known about how sex-specific floral bud development responds to temperature transitions. Here, morphological observations indicated that floral bud growth rates were affected by maximum and minimum air temperature at the later stages of enlargement (stage 4) and later stage of dormancy (stage 8), respectively. We investigated the physiological, biochemical and gene expression changes in floral development and in response to temperature treatment (heat and chilling stress). Male floral buds showed more adverse effects than female floral buds under temperature treatment. Temperature treatment experiments revealed that temperature treatment significantly increased catalase, peroxidase, superoxide dismutase activities and transcription of related genes in female floral buds, whereas malondialdehyde (MDA) significantly increased only in males. Soluble sugars and protein increased both in female and male floral buds but were higher in males. Temperature treatment also caused significant increases in Ca(2+) content and transcription of genes related to calcium transport in female flowers. These results revealed sex-specific floral developmental responses to seasonal temperature transitions and suggest that in Populus tomentosa, female floral buds possess better mechanisms for environment adaptation than do males.

Effect of Gypsum Application on Mineral Composition in Peanut Pod Walls and Seeds

ABSTRACTAlleviation of soil‐Ca deficiency through gypsum amendment increases the yield potential and ensures high seed quality in peanut (Arachis hypogaea L.). The effects of gypsum treatment, plant life cycle, and the fruit development stages on the accrual of several essential minerals (Ca, S, Mg, P, K, Cu, Ni, Mn, Zn, and Fe) and Na were studied in the pod walls and seeds of two runner cultivars, C‐99R and Georgia Green. Calcium concentration was nearly twofold higher in pod walls than in seeds, irrespective of gypsum treatment and cultivar differences. Significant increases in Ca and S, a decrease in P concentration in pod walls and seeds, and a marginal decline in seed‐Mg concentration were discernible following gypsum treatment. Sodium concentration decreased in the pod walls and Zn concentration increased in the seeds due to gypsum treatment. Progression in the plant life cycle stage was positively correlated with Ca accrual in both pod walls and seeds. The small‐seeded cultivar Georgia Green showed tissue‐specific increases in the acquisition of Ca, Mg, and Zn in pod walls and seeds, and a decrease in P concentration in the seeds compared with the large‐seeded cv. C‐99R. Compared with the respective seed maturation stages, the pod walls had lower S, Mg, P, K, and Zn, and higher Ca, Cu, Ni, Mn, Fe, and Na concentrations. While Ca, S, Mg, P, K, Zn, Fe, and Na concentrations declined, Mn concentration increased in both pod walls and seeds during fruit development.

Flow dependent water quality impacts of historic coal and oil shale mining in the Almond River catchment, Scotland

The Almond River catchment in Central Scotland has experienced extensive coal mining during the last 300years and also provides an example of enduring pollution associated with historic unconventional hydrocarbon exploitation from oil shale. Detailed spatial analysis of the catchment has identified over 300 abandoned mine and mine waste sites, comprising a significant potential source of mine related contamination. River water quality data, collected over a 15 year period from 1994 to 2008, indicates that both the coal and oil shale mining areas detrimentally impact surface water quality long after mine abandonment, due to the continued release of Fe and SO42- associated with pyrite oxidation at abandoned mine sites. Once in the surface water environment Fe and SO42- display significant concentration-flow dependence: Fe increases at high flows due to the re-suspension of river bed Fe precipitates (Fe(OH)3); SO42- concentrations decrease with higher flow as a result of dilution. Further examination of Fe and SO4 loading at low flows indicates a close correlation of Fe and SO42- with mined areas; cumulative low flow load calculations indicate that coal and oil shale mining regions contribute 0.21 and 0.31g/s of Fe, respectively, to the main Almond tributary. Decreases in Fe loading along some river sections demonstrate the deposition and storage of Fe within the river channel. This river bed Fe is re-suspended with increased flow resulting in significant transport of Fe downstream with load values of up to 50g/s Fe. Interpretation of major ion chemistry data for 2005–2006 indicates significant increases in Ca2+, Mg2+ and HCO3- in coal mined areas probably as a result of the buffering of proton acidity in mine waters; in the oil shale areas Na− and Cl− become increasing dominant possibly associated with increased urbanisation and saline pore water discharge from unprocessed oil shale waste. The study demonstrates the importance of considering the cumulative impact of point and diffuse contamination sourced from numerous small coal and oil shale mine sites on surface water quality.

Gliotoxicity of the cyanotoxin, β-methyl-amino-L-alanine (BMAA)

The amino acid variant β-methyl-amino-L-alanine (BMAA) has long been associated with the increased incidence and progression of the amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC). Previous studies have indicated that BMAA damages neurons via excitotoxic mechanisms. We have challenged rat olfactory ensheathing cells (OECs) with exogenous BMAA and found it to be cytotoxic. BMAA also induces a significant increase in Ca2+ influx, enhanced production of reactive oxygen species (ROS), and disrupts mitochondrial activity in OECs. This is the first study investigating BMAA toxicity using pure glial cells. These findings align BMAA with the three proposed mechanisms of degeneration in ALS, those being non-cell autonomous death, excitotoxicity and mitochondrial dysfunction.

Treatment with oral paricalcitol in daily clinical practice for patients with chronic kidney disease stage 3-4: a preliminary study.

BackgroundActive vitamin D is an effective treatment for secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD) patients often complicated by hypercalcaemia and hyperphosphataemia. Treatment with paricalcitol, a selective vitamin D receptor activator, has shown benefits by adequately reducing parathyroid hormone (PTH) levels with minimal changes in serum calcium (Ca) and phosphorus (P). The purpose of this study is to present data on the use of oral paricalcitol in real-life clinical practice in patients with CKD stage 3–4 and SHPT.MethodsWe studied 43 patients, M/F: 25/18, median age: 74 years (47–87), CKD stage 3/4: 16/27, with SHPT, who were prescribed oral paricalcitol at recommended doses for 6 months. Monthly measurements of serum intact PTH (iPTH), Ca, P, alkaline phosphatase (ALP), haemoglobin, albumin (ALB), lipid profile, proteinuria and 24-h urine creatinine clearance were performed 3 months before and 6 months after treatment initiation.ResultsParicalcitol induced a significant, early and sustained, through the end of follow-up period, decrease in iPTH and ALP levels and an increase in serum ALB. No significant increase in Ca and P levels as well as in Ca × P product was observed during the study period. No significant changes were found in protein excretion, kidney function and the other measured parameters between baseline and last evaluation. Paricalcitol final median dose was 5 μg/week ranging between 3 and 7 μg/week.ConclusionsIn the context of real-life clinical practice, oral paricalcitol for 6 months is an effective, well-tolerated treatment of SHPT in CKD stage 3–4 with minimal effects on calcium and phosphorus metabolism.

Water decoction of coptidis rhizoma prevents oxidative damage in erythrocytes of mice

Coptidis Rhizoma (Coptis chinensis) has been reported to have antioxidative effect on hemolysis of erythrocytes induced by acetylphenylhydrazine in mice and rats. However, the ability of Coptidis Rhizoma to protect structure and function of erythrocytes membrane and morphology of erythrocytes against oxidative damage remains unknown. In this study, we undertook a characterization of antioxidative activity in erythrocytes membrane of Coptidis Rhizoma using an in vivo model of acetylphenylhydrazine-induced mice together with in vitro studies with 2,2-azo-bis (2-amidinopropane) dihydrochloride-induced erythrocytes for further morphology characterization. Acetylphenylhydrazine-induced mice were treated intragastrically with Coptidis Rhizoma at doses of 0.3, 0.6, and 1.2 g/kg per day for 3 days and at the dose of 0.6 and 1.2 g/kg it showed that there was an increasing trend in membranes cytoskeletal proteins of band I-IV, especially a significant upregulation in band II. Significant increase in phosphatidylserine and phosphatidylcholine content at the dose of 1.2 g/kg Coptidis Rhizoma was obsereved. At all doses of Coptidis Rhizoma, the declined membrane fluidity of acetylphenylhydrazine-induced mice was significantly increased. In addition, at the dose of 1.2 g/kg Coptidis Rhizoma treatment showed a significant increase in Ca2+/Mg2+-ATPase activity and there was an increasing trend in the activity of Na+/K+-ATPase. In vitro, Coptidis Rhizoma protected erythrocytes from 2,2-azo-bis (2-amidinopropane) dihydrochloride-induced hemolysis in a dose-dependent manner at concentrations of 0.25-1.5 mg/ml, and also significantly inhibited the 2,2-azo-bis (2-amidinopropane) dihydrochloride-induced morphological alterations in mice erythrocytes. These results demonstrate that Coptidis Rhizoma is capable of protecting erythrocytes against oxidative damage probably by acting as an antioxidant and maintaining membrane integrity.

Reperfusion Ca2+ Waves in the Intact Heart: A Possible Trigger for the Generation of Reperfusion Arrhythmias

Abnormal intracellular Ca2+ cycling plays a key role in cardiac dysfunction, particularly during the setting of cardiac ischaemia/reperfusion (I/R). At the onset of reperfusion there is an increase in cytosolic Ca2+, which has been usually associated with an uncontrolled influx from the extracellular space. Ca2+ mishandling has been in turn related to reperfusion arrhythmias. However, the basic mechanism for these arrhythmias is still unresolved. We performed experiments to test the hypothesis that the increase in cytosolic Ca2+ at the onset of reperfusion originates in Ca2+ efflux from the sarcoplasmic reticulum (SR) and propagates through the cell as cytosolic Ca2+ waves serving as a trigger for the initiation of reperfusion arrhythmias. By using a combination of pulsed local-field fluorescence (PLFF) and laser scanning confocal microscopy in mouse intact hearts loaded with Rhod-2 and/or Mag-Fluo-4 (cytosolic and/or SR Ca2+ measurements) or Fluo-4 (Ca2+ sparks and waves) and submitted to global I/R (12/30 min), it was found that ischemia evoked an increase in cytosolic and SR Ca2+. This increase was associated with a significant rise in Ca2+ sparks relative to preischemia: 2.07 ± 0.33 vs. 1.13 ± 0.20 sp/sec/100μm (P<0.05, ANOVA). Reperfusion evoked an increment in cytosolic Ca2+ (Ca2+ bump) that was associated with a significant decrease in SR Ca2+ and in Ca2+ sparks with respect to ischemia and a significant increase in Ca2+ waves relative to ischemia and preischemia: 0.71± 0.14 vs. 0.38± 0.06 and 0.25 ± 0.04 w/sec/100μm. The results show the first direct evidence of an increase in Ca2+ sparks in ischemia that transform in Ca2+ waves during reperfusion. These waves may constitute a main trigger of reperfusion arrhythmias. Supported by NIH R01-HL-084487 and PICT/1903 (FONCYT).