Elevated Phosphate Research Articles

Characterizing the Metabolic Determinants of Thromboinflammation in Myeloproliferative Neoplasms

BACKGROUNDMyeloproliferative neoplasms (MPNs) are a group of clonal hematopoietic disorders characterized by an overproduction of terminally differentiated myeloid elements. Venous and arterial thrombotic events represent the leading causes of morbidity and mortality in patients with JAK2 positive MPNs (essential thrombocythemia [ET] and polycythemia vera [PV]) in chronic phase. Platelet hyperreactivity is a hallmark finding of MPNs but the biological mechanisms remain to be elucidated. We have previously identified that platelets from patients with PV and ET exhibit dysmorphic mitochondria, however, the detailed bioenergetic and metabolomic implications of such alterations in mitochondrial mass and morphology remain to be investigated. Here in, we aim to identify the metabolic determinants that underpin thromboinflammation in patients with JAK2 positive MPNs in chronic phase. METHODSPlatelets from sex and age-matched healthy control subjects and individuals with either JAK2 positive PV or ET were isolated and washed following standard protocols. Platelet activation by flow cytometry was determined at baseline conditions. Platelet activated fibrinogen binding site (αIIbβIII), P-selectin, and phosphatidylserine (PS) surface marker expression (as measured by mean fluorescence intensity [MFI]) was determined with PAC-1 and P-selectin antibodies and lactadherin, respectively. The bioenergetic profile of washed platelets was determined by the 24-well format Seahorse extracellular flux analyzer. Metabolomic profile was developed with the Vanquish UHPLC system coupled online to a Q Exactive mass spectrometer. Statistical analyses were performed using the unpaired 2-tailed Student t test (GraphPad Software v9.1.2). Data expressed as mean plus or minus standard error of the mean (SEM). Significance was determined at p < 0.05. RESULTSPlatelets from patients with MPNs had higher surface marker expression of PS under resting conditions. A trend of higher surface marker expression of αIIbβIII and P-selectin was seen (Figure 1). The platelet bioenergetic profile in individuals with MPN demonstrated decreased basal respiration (p = 0.0008), ATP-linked respiration (p = 0.001), and basal extracellular acidification rate (ECAR) (p = 0.09) (Figure 2). Liquid chromatography-mass spectrometry-based metabolomics revealed elevated pentose phosphate pathway metabolites (pentose phosphates and 6-Phospho-D-gluconate), and diminished adenosine diphosphate (ADP) and adenosine triphosphate (ATP) pools (Figure 3). CONCLUSIONThe findings from this study suggest that platelets from patients with JAK2 positive PV and ET have a procoagulant phenotype given the increased expression of PS, an anionic phospholipid known to facilitate the generation of thrombin. The decreased basal respiration, ATP-linked respiration, basal ECAR (a surrogate marker of glycolysis), and energy pools (ADP and ATP) in platelets from MPN patients suggest a hypometabolic phenotype. Additionally, it appears there is preferential shunting of glucose into the pentose phosphate pathway. Such metabolic switch in conjunction with the hypometabolic state of platelets in MPN, could potentially represent a compensatory mechanism of platelets against oxidative stress.The bioenergetic dysregulation of platelets in MPNs may precipitate a cascade of events that leads to the loss of plasma membrane integrity (increased PS exposure) therefore increasing its procoagulant potential. Higher amounts of platelet PS could underly the elevated incidence of thrombosis observed in patients with JAK2 positive ET and PV. Further studies are underway to identify the inciting factor(s) that lead to the platelet bioenergetic failure and elevated PS exposure seen in patients with MPNs. These investigations will provide significant mechanistic insight for identifying therapies aimed at preventing thrombotic events in patients with MPNs. [Display omitted] DisclosuresNemkov: Omix Thecnologies: Other: Co-founder. D'Alessandro: Omix Thecnologies: Other: Co-founder; Rubius Therapeutics: Consultancy; Forma Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Response of phosphorus sensitive plants to arsenate

Arsenate (As (V)) is a highly toxic species of arsenic (As) which is also an excellent phosphate analogue. Plant species that are adapted to phosphorus (P) impoverished soil display a negative response to elevated phosphate due to an inability to downregulate P acquisition. Despite widespread As contamination and shared transport systems for As (V) and P uptake, little to no information is available on the response of P-sensitive plants to As (V). The aim of the study was to investigate the response of P-sensitive plants to As (V). One high (Hakea prostrata R.BR) and one moderate (Banksia seminuda B.Rye) P-sensitive species and one vegetable plant species (Cucumis sativus L.) were grown in nutrient solution containing different As (V) concentrations. Based on EC50 data from nutrient culture, Hakea prostrata was the most sensitive species to As (V) followed by B. seminuda and C. sativus. Critical exogenous concentrations of As that reduced plant growth by 50 % (EC50) in H. prostrata, B. seminuda and C. sativus were respectively 0.64, 0.76 and 1.08 μM for shoot and 0.66, 0.51, 1.07 μM for root. Hakea prostrata had the highest translocation factor (ratio of As concentration in shoot to root) of 0.11, followed by B. seminuda (0.03), and C. sativus (0.01). Plant species with high and moderate P sensitivity were associated with high sensitivity to As (V) exposure and accumulation in shoots. The increased sensitivity has important implications in ecological risk assessment and selection of plant species for rehabilitation. The impacts of As(V) at low P levels in soil solution is needed to inform contaminated site assessment and rehabilitation.

Anti-Urolithiatic Activity of the Ethanolic Extract of Cassia auriculata against Ethylene Glycol Induced Urolithiasis in Experimental Rats

The objective was to investigate the anti-urolithiatic effect of ethanolic extract of Cassia auriculate on ethylene glycol (EG) induced urolithiasis in experimental rats. The animals were divided into five groups of six animals each. Except the normal group all the other groups received ethylene glycol 0.75% and Ammonium chloride 1% v/v in water induce orally for 28 days. Normal groups received plain water orally. The standard group received cystone 750mg/kg b.w orally. Test groups received EECA 200mg/kg and 400mg/kg b.w orally. On the 28th day, blood and urine samples were collected and used for estimation of biochemical parameters such as calcium, phosphates, oxalates, creatinine, uric acid, SOD, and CAT followed by histopathological studies. Treatment with EECA was found to exert dose dependent anti urolithiatic action. Increased urine volume in EECA treated groups as compared to diseased group was indicative of diuretic property. Elevated calcium, phosphate and oxalate levels in diseased group animals were found to be decreased in animals treated with EECA. Increased levels of serum calcium, creatinine and uric acid were considerably brought down towards normal values in proportion to EECA doses administered. Antioxidant parameters like SOD and CAT were decreased along with significant increase in MDA levels which is the main product of lipid peroxidation in EG treated rats. However the rats treated with EECA showed significant improvement in these parameters. Hence it is concluded that the ethanolic extract of Cassia auriculata possess anti-urolithiatic activity.

Dynamics of Nutrients and Colored Dissolved Organic Matter Absorption in a Wetland-Influenced Subarctic Coastal Region of Northeastern Japan: Contributions From Mariculture and Eelgrass Meadows

Coastal oceans interacting with terrestrial ecosystems play an important role in biogeochemical cycles. It is therefore essential to research land–ocean interactions for further understanding of the processes influencing nutrients dynamics in coastal areas. We investigated the seasonal and spatial distribution of nutrient concentrations and light absorption coefficients of colored dissolved organic matter (CDOM), non-algal particles (NAP), and phytoplankton in a wetland-influenced river–eelgrass meadows–coastal waters continuum in the protected and semi-enclosed coastal sea of Akkeshi-ko estuary (AKE) and Akkeshi Bay (AB), Japan from April 2014 to February 2015. The mixing dilution lines of the CDOM absorption coefficient at 355 nm [aCDOM(355)] relative to salinity predicted by two end-members between freshwater and coastal water showed conservative mixing in AB. Silicate concentrations were significantly correlated with salinity and aCDOM(355) in AB in each month except for December 2014. These results suggest that silicate and CDOM in AB primarily originates from wetland-influenced river discharge. However, samples collected from the eelgrass meadows of AKE, where mariculture is developed, showed non-conservative mixing of silicate concentrations and aCDOM(355) with salinity except for June 2014. Elevated phosphate concentrations, probably released from sediments, were also found in the eelgrass meadows of AKE, especially during summer. These results suggest that the metabolic activities of mariculture and seagrass ecosystem significantly contribute to the nutrient cycles and CDOM absorption in AKE and to the distinct water-mass systems inside and outside AKE. The relative absorption properties of NAP [aNAP(443)], phytoplankton [aph(443)], and aCDOM(443) showed that CDOM is the main factor affecting the light distribution in AKE. However, the relative absorption properties varied seasonally in AB because of spring and autumn phytoplankton blooms and ice cover during winter. Significant relationships were observed between the Secchi disk depth (ZSD), aNAP(443), and aCDOM(443). Chl a concentration and aph(443) were not good indicators for predicting ZSD in our study region. These results suggest that incorporating inherent optical properties and CDOM from mariculture and seagrass ecosystem into ecosystem models could improve predictions of light distribution along the freshwater–eelgrass–coastal waters continuum in optically complex coastal waters.

MicroRNA expression under phosphate deficiency stress in red clover (Trifolium pratense L.): a three-year field experiment

ABSTRACT Phosphate deficiency is a stress factor often limiting crop growth and development. The aim of this study was to determine the expression of microRNAs (miRNAs) in response to long-term phosphate stress in red clover populations in field conditions. The sensitivity of six red clover populations to phosphate stress was determined in a three-year field experiment. The results revealed that the declines in hay yield and quality under phosphate stress were less pronounced for two populations compared to the other four. Molecular analysis revealed significant down-regulation (miRNA156, miRNA171 and miRNA2111) and up-regulation (miRNA399) in the phosphate stress-tolerant populations exposed to phosphate stress, but no changes were observed in the non-phosphate stress-tolerant populations. The results collectively suggest that miRNA156, miRNA171, miRNA399 and miRNA2111 could be responsible for tolerance to phosphate limited conditions in some red clovers. These miRNAs could be used for the development of red clover plants that are tolerant of phosphate-deficient soils. In addition, since phosphate stress-tolerant populations should require less phosphate fertiliser, they would have the potential to mitigate environmental pollution from farming soils with elevated phosphate levels.

Dexamethasone-loaded cochlear implants: How to provide a desired “burst release”

Cochlear implants containing iridium platinum electrodes are used to transmit electrical signals into the inner ear of patients suffering from severe or profound deafness without valuable benefit from conventional hearing aids. However, their placement is invasive and can cause trauma as well as local inflammation, harming remaining hair cells or other inner ear cells. As foreign bodies, the implants also induce fibrosis, resulting in a less efficient conduction of the electrical signals and, thus, potentially decreased system performance. To overcome these obstacles, dexamethasone has recently been embedded in this type of implants: into the silicone matrices separating the metal electrodes (to avoid short circuits). It has been shown that the resulting drug release can be controlled over several years. Importantly, the dexamethasone does not only act against the immediate consequences of trauma, inflammation and fibrosis, it can also be expected to be beneficial for remaining hair cells in the long term. However, the reported amounts of drug released at “early” time points (during the first days/weeks) are relatively low and the in vivo efficacy in animal models was reported to be non-optimal. The aim of this study was to increase the initial “burst release” from the implants, adding a freely water-soluble salt of a phosphate ester of dexamethasone. The idea was to facilitate water penetration into the highly hydrophobic system and, thus, to promote drug dissolution and diffusion. This approach was efficient: Adding up to 10% dexamethasone sodium phosphate to the silicone matrices substantially increased the resulting drug release rate at early time points. This can be expected to improve drug action and implant functionality. But at elevated dexamethasone sodium phosphate loadings device swelling became important. Since the cochlea is a tiny and sensitive organ, a potential increase in implant dimensions over time must be limited. Hence, a balance has to be found between drug release and implant swelling.

Asymmetric physiological response of a reef-building coral to pulsed versus continuous addition of inorganic nutrients

Coral reefs, especially those located near-shore, are increasingly exposed to anthropogenic, eutrophic conditions that are often chronic. Yet, corals under unperturbed conditions may frequently receive natural and usually temporary nutrient supplementation through biological sources such as fishes. We compared physiological parameters indicative of long- and short-term coral health (day and night calcification, fragment surface area, productivity, energy reserves, and tissue stoichiometry) under continuous and temporary nutrient enrichment. The symbiotic coral Acropora intermedia was grown for 7 weeks under continuously elevated (press) levels of ammonium (14 µmol L−1) and phosphate (10 µmol L−1) as separate and combined treatments, to discern the individual and interactive nutrient effects. Another treatment exposed A. intermedia twice-daily to an ammonium and phosphate pulse of the same concentrations as the press treatments to simulate natural biotic supplementation. Press exposure to elevated ammonium or phosphate produced mixed effects on physiological responses, with little interaction between the nutrients in the combined treatment. Overall, corals under press exposure transitioned resources away from calcification. However, exposure to nutrient pulses often enhanced physiological responses. Our findings indicate that while continuous nutrient enrichment may pose a threat to coral health, episodic nutrient pulses that resemble natural nutrient supplementation may significantly benefit coral health and physiology.

Adapter Protein RapGEF1 Is Required for ERK1/2 Signaling in Response to Elevated Phosphate in Vascular Smooth Muscle Cells

The sodium-dependent phosphate transporter, SLC20A1, is required for elevated inorganic phosphate (Pi) induced vascular smooth muscle cell (VSMC) matrix mineralization and phenotype transdifferentiation. Recently, elevated Pi was shown to induce ERK1/2 phosphorylation through SLC20A1 by Pi uptake-independent functions in VSMCs, suggesting a cell signaling response to elevated Pi. Previous studies identified Rap1 guanine nucleotide exchange factor (RapGEF1) as an SLC20A1-interacting protein and RapGEF1 promotes ERK1/2 phosphorylation through Rap1 activation. In this study, we tested the hypothesis that RapGEF1 is a critical component of the SLC20A1-mediated Pi-induced ERK1/2 phosphorylation pathway. Co-localization of SLC20A1 and RapGEF1, knockdown of RapGEF1 with siRNA, and small molecule inhibitors of Rap1, B-Raf, and Mek1/2 were investigated. SLC20A1 and RapGEF1 were co-localized in peri-membranous structures in VSMCs. Knockdown of RapGEF1 and small molecule inhibitors against Rap1, B-Raf, and Mek1/2 eliminated elevated Pi-induced ERK1/2 phosphorylation. Knockdown of RapGEF1 inhibited SM22α mRNA expression and blocked elevated Pi-induced downregulation of SM22α mRNA. Together, these data suggest that RapGEF1 is required for SLC20A1-mediated elevated Pi signaling through a Rap1/B-Raf/Mek1/2 cell signaling pathway, thereby promoting ERK1/2 phosphorylation and inhibiting SM22α gene expression in VSMCs.

A Challenging Case of Phosphaturic Mesenchymal Tumor With Primary Hyperparathyroidism

Background: Localization of tumor-induced osteomalacia (TIO) is often challenging. Primary hyperparathyroidism (HPT) following curative surgery for TIO is rarely reported. Clinical Case: A 49-year-old man presented with fragility rib fractures, generalized bone pain, and muscle weakness worsening over the past 3 years. Rheumatologic workup was negative. Initial tests showed elevated levels of parathyroid hormone (PTH) 114.1 pg/mL (14–72 pg/mL) and alkaline phosphatase (ALP) 283 IU/L (44–174 IU/L), reduced levels of 25(OH)D 16 ng/mL (30–100 ng/mL), 1,25(OH)2D 9 pg/mL (18–72 pg/mL), and phosphorus 1.6 mg/dL (2.5–4.9 mg/dL), calcium levels of 9.2 mg/dL (8.5–10.1 mg/dL), and eGFR 58 mL/min/1.73 m2. A sestamibi scan showed normal parathyroid uptake. The diagnosis was secondary HPT due to chronic kidney disease and vitamin D deficiency. The patient was treated with D3 and phosphate. During a 2-year follow-up, the patient reported improvement of pain and weakness with no additional fractures. Further investigations showed persistent hypophosphatemia with elevated urinary fractional phosphate excretion (44%, ref. <20%), indicating renal phosphate wasting. Fibroblast Growth Factor 23 (FGF23) was high, 291 RU/mL (0–180 RU/mL). DXA results were consistent with osteopenia. TIO was suspected. At a 3-year follow-up, investigations included three whole-body 18F-FDG PET-CT scans revealing several areas suspicious for tumor presence. However, multiple MRIs were inconclusive. Laboratory tests showed persistent hypophosphatemia (despite D3 and phosphate treatment), elevated FGF23 (1330 RU/mL) and PTH (274.4 pg/mL), and normal calcium, 25(OH)D, and 1,25(OH)2D. The patient subsequently underwent 68Ga DOTATATE PET-CT, which revealed a somatostatin receptor-positive lesion involving the left upper lobe of the lung. The mass was resected without complications. Histopathology was compatible with a phosphaturic mesenchymal tumor. At a 6-month postoperative follow-up, the patient reported dramatically improved symptoms with decreased weakness and pain, normal phosphate, calcium, ALP, and FGF23 (160 RU/mL) levels, while DXA results were significantly improved. Phosphorus supplementation was discontinued. At follow-up 3 years post-surgery, the patient had slowly rising PTH (126.3 pg/mL) and calcium (10.1–10.6 mg/dL) levels with normal phosphate, 25(OH)D, and FGF23 (174 RU/mL) levels. A diagnosis of primary HPT was made. Further evaluation was deemed unnecessary since the patient did not meet the criteria for surgical treatment. The development of primary HPT was considered mechanistically related to long-standing hypophosphatemia and hypovitaminosis D stimulating PTH production. Conclusion: This case report highlights the pitfalls contributing to delayed diagnosis of TIO and alerts clinicians to the potential development of primary HPT after curative surgery for TIO.

Hyperphosphatemia Contributes to Skeletal Muscle Atrophy in Chronic Kidney Disease

Alterations in mineral metabolism involve changes in serum levels of phosphate as well as its key regulators, fibroblast growth factor 23 (FGF23), vitamin D, parathyroid hormone and klotho. Chronic Kidney Disease (CKD) is a public health epidemic that affects an estimated 37 million Americans, and is associated with elevated serum levels of phosphate (hyperphosphatemia) and FGF23 as well as various pathologies, such vascular calcification, cardiac hypertrophy, and skeletal muscle atrophy. We previously found that elevated FGF23 directly targets cardiac myocytes and contributes to cardiac hypertrophy. Furthermore, elevated phosphate has direct effects on smooth muscle cells and induces vascular calcification. In order to determine whether FGF23 and/or phosphate might also contribute to CKD-associated skeletal muscle atrophy, we tested if skeletal muscle cells can respond to elevations of FGF23 or phosphate. Since the skeletal muscle phenotype in CKD is not well characterized, we analyzed skeletal muscle on a functional, histological, and molecular level in two established mouse models of CKD. We studied the C2C12 skeletal muscle cell line during the differentiation process from myoblasts to myotubes as well as fully differentiated myotubes. Myoblast differentiation was induced with horse serum; cells were co-treated with 25 ng/ml FGF23 or 5 mM phosphate for 5 days, followed by the expression analysis of differentiation markers by qPCR. In a separate study, differentiated C2C12 myotubes were treated with FGF23 or phosphate for 24 hours, followed by the qPCR analysis of atrophy genes (atrogenes), including MT1, Murf1, and Fbox32. Furthermore, we studied mice with global deletion of collagen 4a3 (Col4a3-/-) and wildtype littermates at 10 weeks of age, as well as C57Bl/6 mice receiving an adenine-rich (0.2%) diet or regular chow for 12 weeks. In all mice we studied grip strength, hindlimb circumference by MRI, cross-sectional area of individual muscle fibers that were immuno-labeled with anti-laminin by fluorescence microscopy, and expression levels of atrogenes by qPCR. Phosphate but not FGF23 affected the differentiation process of C2C12 myoblasts and differentiated C2C12 myotubes. Phosphate treatments significantly reduced expression levels of MyoD and MyoG and increased expression of MT1. In both mouse models, grip strength and areas of hindlimb and myotubes were significantly reduced, and expression levels of MT1 and Murf1 were significantly elevated when compared to their controls. FGF23 does not target skeletal muscle cells suggesting that it cannot directly contribute to skeletal muscle atrophy. Elevated phosphate impairs myoblast differentiation and induces atrophy in vitro. We have characterized two CKD mouse models with associated skeletal muscle atrophy, where we will now determine the contribution of hyperphosphatemia to the injury process. Pharmacological approaches targeting phosphate uptake or excretion, or phosphate's direct actions on tissues might alleviate various CKD-associated pathologies.

Heme-Mediated Activation of the Nrf2/HO-1 Axis Attenuates Calcification of Valve Interstitial Cells.

Calcific aortic valve stenosis (CAVS) is a heart disease characterized by the progressive fibro-calcific remodeling of the aortic valves, an actively regulated process with the involvement of the reactive oxygen species-mediated differentiation of valvular interstitial cells (VICs) into osteoblast-like cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of a variety of antioxidant genes, and plays a protective role in valve calcification. Heme oxygenase-1 (HO-1), an Nrf2-target gene, is upregulated in human calcified aortic valves. Therefore, we investigated the effect of Nrf2/HO-1 axis in VIC calcification. We induced osteogenic differentiation of human VICs with elevated phosphate and calcium-containing osteogenic medium (OM) in the presence of heme. Heme inhibited Ca deposition and OM-induced increase in alkaline phosphatase and osteocalcin (OCN) expression. Heme induced Nrf2 and HO-1 expression in VICs. Heme lost its anti-calcification potential when we blocked transcriptional activity Nrf2 or enzyme activity of HO-1. The heme catabolism products bilirubin, carbon monoxide, and iron, and also ferritin inhibited OM-induced Ca deposition and OCN expression in VICs. This study suggests that heme-mediated activation of the Nrf2/HO-1 pathway inhibits the calcification of VICs. The anti-calcification effect of heme is attributed to the end products of HO-1-catalyzed heme degradation and ferritin.

The Leloir Cycle in Glioblastoma: Galactose Scavenging and Metabolic Remodeling.

Simple SummaryProliferation of glioblastoma (GBM) depends on access to extracellular nutrients. Inadequate tumor perfusion creates a short supply of the most common nutrients, such as glucose (Glc) and glutamine. As a result, GBMs undergo metabolic remodeling and scavenge alternative nutrients from the tumor microenvironment for their growth and proliferation. GBM expresses sugar transporters, such as Glut3 and Glut14. Galactose (Gal) is a good substrate for Glut3/Glut14, and GBM cells can scavenge Gal from the circulation/extracellular space. The Leloir pathway allows GBM to transport and metabolize Gal at physiologic Glc concentrations, providing GBM cells with an alternate energy source. GBM cultures proliferated when grown solely on Gal. GBMs metabolize Gal via the Leloir pathway, glycolysis, and pentose phosphate pathway (PPP) to optimize ATP production, while the mitochondrial metabolism of Gal in GBM is limited. The selective targeting of the Leloir/PPP pathway may provide new treatment strategies for GBM.Background: Glioblastoma (GBM) can use metabolic fuels other than glucose (Glc). The ability of GBM to use galactose (Gal) as a fuel via the Leloir pathway is investigated. Methods: Gene transcript data were accessed to determine the association between expression of genes of the Leloir pathway and patient outcomes. Growth studies were performed on five primary patient-derived GBM cultures using Glc-free media supplemented with Gal. The role of Glut3/Glut14 in sugar import was investigated using antibody inhibition of hexose transport. A specific inhibitor of GALK1 (Cpd36) was used to inhibit Gal catabolism. Gal metabolism was examined using proton, carbon and phosphorous NMR spectroscopy, with 13C-labeled Glc and Gal as tracers. Results: Data analysis from published databases revealed that elevated levels of mRNA transcripts of SLC2A3 (Glut3), SLC2A14 (Glut14) and key Leloir pathway enzymes correlate with poor patient outcomes. GBM cultures proliferated when grown solely on Gal in Glc-free media and switching Glc-grown GBM cells into Gal-enriched/Glc-free media produced elevated levels of Glut3 and/or Glut14 enzymes. The 13C NMR-based metabolic flux analysis demonstrated a fully functional Leloir pathway and elevated pentose phosphate pathway activity for efficient Gal metabolism in GBM cells. Conclusion: Expression of Glut3 and/or Glut14 together with the enzymes of the Leloir pathway allows GBM to transport and metabolize Gal at physiological glucose concentrations, providing GBM cells with an alternate energy source. The presence of this pathway in GBM and its selective targeting may provide new treatment strategies.

Biomineralization of Uranium-Phosphates Fueled by Microbial Degradation of Isosaccharinic Acid (ISA).

Geological disposal is the globally preferred long-term solution for higher activity radioactive wastes (HAW) including intermediate level waste (ILW). In a cementitious disposal system, cellulosic waste items present in ILW may undergo alkaline hydrolysis, producing significant quantities of isosaccharinic acid (ISA), a chelating agent for radionuclides. Although microbial degradation of ISA has been demonstrated, its impact upon the fate of radionuclides in a geological disposal facility (GDF) is a topic of ongoing research. This study investigates the fate of U(VI) in pH-neutral, anoxic, microbial enrichment cultures, approaching conditions similar to the far field of a GDF, containing ISA as the sole carbon source, and elevated phosphate concentrations, incubated both (i) under fermentation and (ii) Fe(III)-reducing conditions. In the ISA-fermentation experiment, U(VI) was precipitated as insoluble U(VI)-phosphates, whereas under Fe(III)-reducing conditions, the majority of the uranium was precipitated as reduced U(IV)-phosphates, presumably formed via enzymatic reduction mediated by metal-reducing bacteria, including Geobacter species. Overall, this suggests the establishment of a microbially mediated "bio-barrier" extending into the far field geosphere surrounding a GDF is possible and this biobarrier has the potential to evolve in response to GDF evolution and can have a controlling impact on the fate of radionuclides.

Phosphorus enrichment masked the negative effects of ocean acidification on picophytoplankton and photosynthetic performance in the oligotrophic Indian Ocean

Dynamics of picophytoplankton and photosynthesis will be inevitably impacted by changing marine environment, such as ocean acidification and nutrient supply, but related studies are very scarce. Here we cultured the picophytoplankton-dominated surface water of the oligotrophic Eastern Indian Ocean (EIO; R/V Shiyan-3, 20 March to 18 May 2019) at two levels of pCO2 (400 and 1000 ppm) and phosphate (0.05 and 1.50 µM) to investigate the interactive effects of elevated pCO2 and phosphate (P) on the dynamics of picophytoplankton and photosynthetic properties. High pCO2 and P levels interactively increased the abundances of Synechococcus, Prochlorococcus and picoeukaryotes by 33%, 18%, and 21%, respectively, of which high P level had a major promoting effect. Conversely, rising pCO2 alone decreased their abundances by 9%, 32%, and 46%, respectively. For the photophysiological responses in relation to the combination of high pCO2 and P levels, there was an increase in the maximum (Fv/Fm) and effective (Fq'/Fm') photochemical efficiency, the electron transfer rates (ETRRCII) and the charge separation rates (JVPSII, an indicator of primary production), but a decrease in the non-photochemical quenching (NPQNSV). Elevated pCO2 alone facilitated the NPQNSV process significantly, ultimately leading to reduced light use efficiency (e.g., Fv/Fm, Fq'/Fm' and ETRRCII) and primary production (JVPSII). There was a strong coupling of picophytoplankton and JVPSII, suggesting the EIO primary productivity was potentially controlled by picophytoplankton. Overall, our results indicate that the negative effects caused by ocean acidification may be masked or outweighted by the role that P availability plays in regulating growth and metabolism in this oligotrophic ecosystem.

Simultaneous presence of atrial arrhythmia and hypocalcemia in dilated cardiomyopathy: A series of two cases

Dilated cardiomyopathy in young children has varied etiological factors. Some cases have correctable causes such as incessant arrhythmia, correctable metabolic abnormality, and left ventricular obstructive lesions. Two 4-month-old infants presented with severe left ventricular dysfunction and ectopic atrial tachycardia. Biochemical profile of the infants showed low ionic and total calcium, elevated serum phosphate, elevated alkaline phosphatase, and elevated serum lactate. The parathyroid hormone was elevated and 25-hydroxyvitamin D3 was reduced. The patients were treated with beta-blocker, calcium, and Vitamin D supplementation, along with antifailure therapy. The tachycardia resolved over a 12-h period and calcium normalized in the next few days. The left ventricular function returned to normal over a 5–16-month period. In 6–8 years of follow-up, patients were in sinus rhythm doing very well with normal cardiac function with normal calcium-related biochemical parameters. The presence of incessant atrial arrhythmia in a case of hypocalcemic cardiomyopathy is rare and can have link with hypocalcemia-induced electrical changes in the cardiomyocyte in selected cases. Thorough and protocol-based treatment approach helps in correct diagnosis and treatment. Further study and molecular research can shed more light on the complex interaction of hypocalcemia and arrhythmia.

NaPi-IIb Inhibition for Hyperphosphatemia in CKD Hemodialysis Patients

IntroductionChronic kidney disease (CKD) has a prevalence of 9.1% globally, and frequently results in elevated serum phosphate, increasing cardiovascular morbidity and mortality risk in hemodialysis (HD) patients. DS-2330b, an oral NaPi-IIb inhibitor, reduced intestinal phosphate absorption in preclinical studies, but its effect in patients with CKD is unknown. This 2-part, randomized, placebo- and active-controlled, single- and repeated-dose, phase 1b study evaluated safety and efficacy of DS-2330b in patients with CKD on HD.MethodsPart A, a 2-period, 2-way study, evaluated safety and pharmacokinetics of DS-2330b 250 mg in solution and tablet formulations. Part B assessed the safety of DS-2330b in solution (chosen based on results of part A) and its effect on serum phosphate. Patients were randomized to placebo 3 times daily (TID), DS-2330b 400 mg TID, DS-2330b 400 mg with sevelamer 1.6 g TID, and sevelamer 1.6 g with placebo TID for 14 days. Safety endpoints included adverse event (AE) monitoring.ResultsSix patients completed part A. Two patients experienced serious AEs considered unrelated to DS-2330b treatment. Thirty-two patients enrolled and completed part B. Serum phosphate mean change from baseline ± SD was −2.2±1.5 mg/dl versus −1.9 ± 1.1 mg/dl for DS-2330b monotherapy versus placebo. Patients receiving DS-2330b with sevelamer or sevelamer with placebo experienced the greatest serum phosphate decrease from baseline. Nine patients (28.1%) experienced ≥1 treatment-emergent AE (TEAE); 7 patients experienced drug-related TEAEs. The TEAE incidence was comparable between DS-2330b and control groups.ConclusionsDS-2330b, alone or in combination with sevelamer, was safe and well tolerated but did not demonstrate clinically meaningful efficacy in HD patients.

Seasonal Variation on the Hydrochemistry and Height of Brackish-Water from Commodore Channel, Lagos, Nigeria

The current study deals with the evaluation of physicochemical characteristics, nutrient status, and variation in the height of surface water from the commodore channel, and its comparison with the hydrochemical characteristics of the monitoring borehole from the NIOMR Jetty, Lagos, Nigeria. We aim to further improve our understanding of the interrelationship of climate change and hydrological cycle, and its impacts in the Lagos coastal environments. The observed ranges of physicochemical characteristics of the surface water are dissolved oxygen (DO) 3.07-6.05mg/L; pH: 7.99-8.48; temperature 26.97-30.34°C, electrical conductivity (EC) 9680-47800mS/cm; salinity (Sal) 6.51-28.05‰ and water level 1.24-1.79m. The concentration of nutrient range from nitrite 10-36mg/l, nitrate 28-44mg/l, sulphate 38-90mg/l and phosphate 2-78mg/l. The analyzed hydrochemical characteristics from all the stations are within the desired values for healthy marine ecosystems when compared with Federal Ministry of Environment (FMENV) Nigeria permissible limits which are: DO &gt;5 mg/l, pH 6.5-9, temperature &lt;40°C, nitrite 1mg/l, nitrate 20mg/l, phosphate 5mg/l and sulphate 500mg/l; except low DO (&lt;4.5mg/l) in January, November and December, and elevated nitrite, nitrate and phosphate values across the season. The low DO values may be attributed to enhanced transportation of non-biodegradable organic loads that utilize the available DO for chemical oxidation and microbial decomposition. While the enriched nitrite, nitrate and phosphate concentrations suggest enhanced productivity and influx of nutrients rich flood water from the anthropogenic source. Our study showed a coincidence in the highest brackish water height of the surface water (1.24m) from the commodore channel with the highest groundwater level (1.58m) in October. The lowest height of water levels was recorded in February and March at 2.23m and 1.79m for groundwater and surface water respectively. The similarities in the height of water levels were recorded with contrasting hydrochemical variables (e.g., high Ec vs. low Ec; and high Sal vs. low Sal), which confirmed the effect of rainfall/freshwater incursion on the surface water and simultaneous occurrence of subsurface pollution arising from seawater intrusion on the groundwater samples in October. This study had shown that a long term monitoring of rise in water levels and hydrochemical variables of surface and groundwater can be used to understand climate change and early warning predictions of flooding in coastal environments.

Tumor Lysis Syndrome Risk in Outpatient Versus Inpatient Administration of Venetoclax and Hypomethlators for Acute Myeloid Leukemia

Introduction Venetoclax (VEN), a BCL-2 inhibitor, along with hypomethylating agents (HMAs) has become standard therapy for older patients (pts) with acute myeloid leukemia (AML) not fit for intensive frontline therapy based on recent Phase 3 data reporting a median overall survival (OS) of 14.7 months. Initially used in CLL, VEN is associated with fatal episodes of tumor lysis syndrome (TLS). Package insert and expert opinion recommendations are for its initiation in the inpatient setting, with a dose escalation of 100mg day 1, 200mg day 2, and 400mg day 3 with IV hydration and close monitoring of TLS markers. In the initial phase 1b trial that resulted in its approval for use in pts with AML all pts were admitted to the hospital for initial venetoclax ramp up and received at least 72 hours of prior TLS prophylaxis, as well as initiation of venetoclax only if the white blood cell count was less than 25,000. No episodes of TLS were documented. Herein, we evaluated the safety of outpatient VEN ramp up when given in addition to HMAs for the treatment of AML. Methods We conducted a retrospective review of pts diagnosed with AML at our institution from 12/1/2016 until 7/1/2020. We identified pts who received HMAs and VEN, either as up-front treatment for newly diagnosed AML or as salvage therapy for relapsed or refractory disease, and stratified pts based on whether venetoclax was initiated in the inpatient or outpatient setting. We then examined baseline AML characteristics including initial blast count, cytogenetics and molecular profiles as well as baseline TLS markers prior to the initiation of VEN. Finally, using the Cairo-Bishop Criteria we examined the number of episodes of laboratory or clinical tumor lysis in all pts. Fisher's exact test and Wilcoxon rank-sum tests were performed to examine differences in categorical and continuous variables. Results Between 12/1/2016 and 7/1/2020 43 pts at received VEN in addition to an HMA for the treatment of AML (Table 1). 39 pts (91%) had VEN initiation and ramp up in the outpatient setting. Amongst all pts 24 received azacitadine, 11 decitabine, and 8 received both HMAs at some point during therapy. Twenty-two pts received HMA and VEN as frontline treatment while the other 21 received it as salvage therapy. There were 28 pts who received venetoclax within 28 days of starting the HMA, 25 of whom received it as an outpatient and 3 as an inpatient. Pretreatment labs were notable for median normal values of potassium, phosphate, uric acid, calcium and creatinine (Table 1). The median pretreatment creatinine levels between the two groups were not significantly different. Median pre-treatment WBC count was noted to be significantly higher in the inpatient cohort (37.9 vs 5.5, p-value of 0.01). Cytogenetic and molecular characteristics are included in the table with the only significant difference being a larger percentage of DNMT3A mutation in the inpatient group. While identification of TLS was somewhat limited by incomplete data on all pts, there was only one identified episode of laboratory TLS (2.5%) with an elevated phosphate and uric acid. This occurred in the outpatient group in a patient whose pretreatment WBC count was greater than 25,000. This pt required admission to the hospital for rasburicase and IV fluids with resolution of the laboratory effects without resultant clinical TLS. There were no episodes of clinical TLS in either group. 30-day mortality from starting VEN was 0% in both groups. While the Cairo-Bishop Criteria require the presence of 2 lab abnormalities to diagnose TLS we did a further analysis to evaluate for the presence of even a single lab abnormality associated with TLS. We identified 3 additional pts (7.5%) in the outpatient cohort who had the presence of only one lab abnormality associated with TLS within the 7 days after initiating treatment. None of these pts required any further TLS directed treatment or hospitalization. Conclusion Our experience with HMAs and VEN showed that outpatient ramp up of venetoclax is safe with a very low risk of laboratory TLS (2.5%) and no evidence of clinical TLS within our cohort. Even with an expanded definition of TLS we only identified 3 additional pts who developed laboratory abnormalities associated with TLS. Our results suggest that, in addition to HMA, VEN ramp up can be safely delivered with monitoring to pts with a WBC count less than 25,000 in the outpatient setting. Disclosures Olszewski: Genentech, Inc.: Research Funding; Spectrum Pharmaceuticals: Research Funding; TG Therapeutics: Research Funding; Adaptive Biotechnologies: Research Funding.

Multiple Autoimmune Syndrome: An Unusual Combination of Autoimmune Disorders

Autoimmune diseases are multifactorial with environmental and heritable factors. Autoimmunity reflects an altered immune status, therefore the presence of more than one disorder is not uncommon. The coexistence of three or more autoimmune diseases in a patient constitutes multiple autoimmune syndrome (MAS). This is an interesting case of a middle-aged female who had celiac disease, primary biliary cholangitis, autoimmune hepatitis and evolving CREST (Calcinosis, Rhaynaud's phenomenon, Esophageal dysmotility, Sclerodactyly and Telangiectasia) syndrome. Fifty years old female patient presented with generalized fatigue, fever, weight loss, vertigo and constipation. She was a diagnosed case of celiac disease, and responded well to glutenfree diet. Family history was unremarkable for any autoimmune disorder. Laboratory workup showed normal complete blood counts, markedly elevated transaminases and alkaline phosphates. Her antinuclear antibodies (ANA) test was strongly positive (>1:320) and showed an anti-centromere pattern. Anti-extractable nuclear antibody(ENA) assay showed anti-mitochondrial and anti- CENP B antibodies. Liver biopsy revealed overlap syndrome (primary biliary cholangitis and autoimmune hepatitis). This patient had celiac disease, primary biliary cholangitis and autoimmune hepatitis. Extensive immunological workup unexpectedly revealed the presence of anti-centromere protein B (anti-CENP B) antibodies which are strongly associated with CREST syndrome. Clinical re-evaluation of the patient gave clues of the evolving CREST syndrome. This case report highlights the importance of adequate immunological investigations in conjunction with clinical information for adequate patient management to achieve favorable consequences in the future. Patients suffering from an autoimmune disease need special attention as multiple immune- mediated disorders may be present simultaneously or sequentially during the course of the disease process. MAS patients are at a higher risk of acquiring infections and tumor development due to prolonged use of immunosuppressants. These patients need close surveillance for the development of another autoimmune disease, so as to control the current disease and to prevent future complications. This case report emphasizes the importance of a multidisciplinary team approach including an immunologist who may facilitate a better understanding of disorders related to the breakdown of immune tolerance.

Rapid Colorimetric Screening of Elevated Phosphate in Urine: A Charge-Transfer Interaction.

A charge-transfer (CT) interaction between 1,3,5-trinitro-2,4-dimethylbenzene (TNX) and anionic phosphate is evaluated, yielding a high band electronic transfer interaction that can be observed as a distinct color change when phosphate is present in solution. The induced interaction was studied using 1H NMR, UV–visible, and Fourier transform infrared spectroscopies. The stoichiometric determination of the interaction was divined by means of continuous variation, applying the Schaeppi–Treadwell method to calculate the binding constant (k). Furthermore, the effect of the polarity of solvents toward the generation of the CT interaction was examined, with multiple solvents considered. Complex deconstruction studies were undertaken, examining the effects of water on complex destruction and understanding the volumes needed to hinder the CT interaction potency. Specificity and selectivity of the CT interaction were also studied against other biologically relevant species (CH3CH2OH, Na+, K+, Ca2+, Cl–, HCO3–, F–, CH3COO–, and SO42–), assessing the capabilities of the assay to differentiate anionic species and counter cations that could act as interferences. The role of TNX concentration in CT formation was also analyzed, aiming to optimize the phosphate-sensing assay and improve its limit of detection. The sensing platform was subsequently used to study phosphate concentrations in urine samples to further understand its potential application in biomedical research. To validate the developed technique, urine samples were analyzed for their phosphate content with both the developed sensor and a validated vanadate–molybdate reagent. The results indicate that the sensing method is capable of accurately reporting elevated phosphate levels in urine samples in a rapid and sensitive manner, illustrating that the colorimetric test could be used as a prescreening test for conditions such as hyperphosphatemia or chronic kidney disease.