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Sample records for cotransporter nbce1 variants

  1. Oligomeric structure and minimal functional unit of the electrogenic sodium bicarbonate cotransporter NBCe1-A.

    Science.gov (United States)

    Kao, Liyo; Sassani, Pakan; Azimov, Rustam; Pushkin, Alexander; Abuladze, Natalia; Peti-Peterdi, Janos; Liu, Weixin; Newman, Debra; Kurtz, Ira

    2008-09-26

    The electrogenic sodium bicarbonate cotransporter NBCe1-A mediates the basolateral absorption of sodium and bicarbonate in the proximal tubule. In this study the oligomeric state and minimal functional unit of NBCe1-A were investigated. Wild-type (wt) NBCe1-A isolated from mouse kidney or heterologously expressed in HEK293 cells was predominantly in a dimeric state as was shown using fluorescence energy transfer, pulldown, immunoprecipitation, cross-linking experiments, and nondenaturing perfluorooctanoate-PAGE. NBCe1-A monomers were found to be covalently linked by S-S bonds. When each of the 15 native cysteine residues were individually removed on a wt-NBCe1-A backbone, dimerization of the cotransporter was not affected. In experiments involving multiple native cysteine residue removal, both Cys(630) and Cys(642) in extracellular loop 3 were shown to mediate S-S bond formation between NBCe1-A monomers. When native NBCe1-A cysteine residues were individually reintroduced into a cysteineless NBCe1-A mutant backbone, the finding that a Cys(992) construct that lacked S-S bonds functioned normally indicated that stable covalent linkage of NBCe1-A monomers was not a necessary requirement for functional activity of the cotransporter. Studies using concatameric constructs of wt-NBCe1-A, whose activity is resistant to methanesulfonate reagents, and an NBCe1-A(T442C) mutant, whose activity is completely inhibited by methanesulfonate reagents, confirmed that NBCe1-A monomers are functional. Our results demonstrate that wt-NBCe1-A is predominantly a homodimer, dependent on S-S bond formation that is composed of functionally active monomers.

  2. Defective membrane expression of the Na(+)-HCO(3)(-) cotransporter NBCe1 is associated with familial migraine.

    Science.gov (United States)

    Suzuki, Masashi; Van Paesschen, Wim; Stalmans, Ingeborg; Horita, Shoko; Yamada, Hideomi; Bergmans, Bruno A; Legius, Eric; Riant, Florence; De Jonghe, Peter; Li, Yuehong; Sekine, Takashi; Igarashi, Takashi; Fujimoto, Ichiro; Mikoshiba, Katsuhiko; Shimadzu, Mitsunobu; Shiohara, Masaaki; Braverman, Nancy; Al-Gazali, Lihadh; Fujita, Toshiro; Seki, George

    2010-09-07

    Homozygous mutations in SLC4A4, encoding the electrogenic Na(+)-HCO(3)(-) cotransporter NBCe1, have been known to cause proximal renal tubular acidosis (pRTA) and ocular abnormalities. In this study, we report two sisters with pRTA, ocular abnormalities, and hemiplegic migraine. Genetic analysis ruled out pathological mutations in the known genes for familial hemiplegic migraine, but identified a homozygous 65-bp deletion (Delta65bp) in the C terminus of NBCe1, corresponding to the codon change S982NfsX4. Several heterozygous members of this family also presented glaucoma and migraine with or without aura. Despite the normal electrogenic activity in Xenopus oocytes, the Delta65bp mutant showed almost no transport activity due to a predominant cytosolic retention in mammalian cells. Furthermore, coexpression experiments uncovered a dominant negative effect of the mutant through hetero-oligomer formation with wild-type NBCe1. Among other pRTA pedigrees with different NBCe1 mutations, we identified four additional homozygous patients with migraine. The immunohistological and functional analyses of these mutants demonstrate that the near total loss of NBCe1 activity in astrocytes can cause migraine potentially through dysregulation of synaptic pH.

  3. Defective membrane expression of the Na+-HCO3− cotransporter NBCe1 is associated with familial migraine

    Science.gov (United States)

    Suzuki, Masashi; Van Paesschen, Wim; Stalmans, Ingeborg; Horita, Shoko; Yamada, Hideomi; Bergmans, Bruno A.; Legius, Eric; Riant, Florence; De Jonghe, Peter; Li, Yuehong; Sekine, Takashi; Igarashi, Takashi; Fujimoto, Ichiro; Mikoshiba, Katsuhiko; Shimadzu, Mitsunobu; Shiohara, Masaaki; Braverman, Nancy; Al-Gazali, Lihadh; Fujita, Toshiro; Seki, George

    2010-01-01

    Homozygous mutations in SLC4A4, encoding the electrogenic Na+-HCO3− cotransporter NBCe1, have been known to cause proximal renal tubular acidosis (pRTA) and ocular abnormalities. In this study, we report two sisters with pRTA, ocular abnormalities, and hemiplegic migraine. Genetic analysis ruled out pathological mutations in the known genes for familial hemiplegic migraine, but identified a homozygous 65-bp deletion (Δ65bp) in the C terminus of NBCe1, corresponding to the codon change S982NfsX4. Several heterozygous members of this family also presented glaucoma and migraine with or without aura. Despite the normal electrogenic activity in Xenopus oocytes, the Δ65bp mutant showed almost no transport activity due to a predominant cytosolic retention in mammalian cells. Furthermore, coexpression experiments uncovered a dominant negative effect of the mutant through hetero-oligomer formation with wild-type NBCe1. Among other pRTA pedigrees with different NBCe1 mutations, we identified four additional homozygous patients with migraine. The immunohistological and functional analyses of these mutants demonstrate that the near total loss of NBCe1 activity in astrocytes can cause migraine potentially through dysregulation of synaptic pH. PMID:20798035

  4. Functional role of a putative carbonic anhydrase II-binding domain in the electrogenic Na+ -HCO₃- cotransporter NBCe1 expressed in Xenopus oocytes.

    Science.gov (United States)

    Yamada, Hideomi; Horita, Shoko; Suzuki, Masashi; Fujita, Toshiro; Seki, George

    2011-01-01

    The electrogenic Na+ -HCO₃⁻ cotransporter NBCe1 plays essential roles in the regulation of systemic and/or local pH. Homozygous inactivating mutations in NBCe1 cause proximal renal tubular acidosis associated with ocular abnormalities. We recently showed that defective membrane expression of NBCe1, caused by several mutations such as Delta65bp (S982NfsX4), is also associated with familial migraine. The Delta65bp mutant is quite unique in that it lacks a putative carbonic anhydrase (CA) II-binding domain but still shows an apparently normal transport activity in Xenopus oocytes. In this addendum, we show that the co-expression of CAII together with the wild-type NBCe1 or the Delta65bp mutant does not enhance the NBCe1 activities in oocytes. Moreover, a carbonic anhydrase inhibitor acetazolamide fails to inhibit the wild-type or the Delta65bp activities co-expressed with CAII. These results indicate that a bicarbonate transport metabolon proposed for the interaction between CAII and NBCe1 does not work at least in Xenopus oocytes.

  5. Inhibition of the Na/bicarbonate cotransporter NBCe1-A by diBAC oxonol dyes relative to niflumic acid and a stilbene.

    Science.gov (United States)

    Liu, Xiaofen; Williams, Jennifer B; Sumpter, Brandon R; Bevensee, Mark O

    2007-02-01

    Na/HCO(3) cotransporters (NBCs) are important regulators of intracellular pH (pH(i) in a variety of organ systems where acid-base status is critical for tissue function. To characterize the pharmacology of NBCs in more detail, we used the two-electrode voltage-clamp technique to examine the effect of previously identified inhibitors of anion exchanger 1 (AE1) on the activity of rat NBCe1-A expressed in Xenopus laevis oocytes. NBC-expressing oocytes voltage-clamped at -60 mV and exposed to a 5% CO(2)/33 mM HCO(3)(-) solution displayed NBC-mediated outward currents that were inhibited by either niflumic acid or one of the two bis-oxonol dyes diBA(3)C4 and diBA(5)C4. NBCe1-A was less sensitive to niflumic acid (apparent K(i) of 100 microM) than 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS, apparent K(i) of 36 microM) but more sensitive to the diBAC dyes (apparent K(i) of approximately 10 microM). Based on current-voltage relationships, the diBAC dyes inhibited HCO(3)(-) -induced NBCe1-mediated inward currents more so than outward currents. NBCe1 sensitivity to the dyes was (1) lower in the presence of 40 microM DIDS, (2) unaffected by changes in external HCO(3)(-) concentration and (3) only modestly higher at an external Na(+) concentration of 5, but not 15 or 33, mM. Therefore, the diBAC dyes compete with DIDS but not appreciably with Na(+) or HCO(3)(-) for binding. The mechanism of diBAC inhibition of NBCe1 appears similar to that previously reported for AE1.

  6. Preliminary X-ray diffraction analysis of the cytoplasmic N-terminal domain of the Na/HCO{sub 3} cotransporter NBCe1-A

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Harindarpal S., E-mail: hs.gill@yale.edu; Boron, Walter F. [Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520 (United States)

    2006-06-01

    The N-terminal, cytoplasmic domain of the Na{sup +}-coupled HCO{sub 3} cotransporter NBCe1-A crystallizes in the trigonal space group P3{sub 1}21 or P3{sub 1} with pseudo P3{sub 1}21 symmetry and diffracts X-rays to 3.0 Å resolution. The crystal packing demonstrates a domain-swap mechanism for dimerization. The N-terminal cytoplasmic domain of the Na{sup +}-coupled HCO cotransporter NBCe1-A (NtNBCe1) has been linked with proximal renal tubular acidosis. In a previous purification study of recombinant NtNBCe1, crystal growth at a suboptimal protein concentration (<1 mg ml{sup −1}) yielded small single diamond-shaped crystals that diffracted poorly. In the present study, by increasing the protein concentration 50-fold, the crystal size was doubled and robustness was also improved. Crystal annealing made the crystals suitable for X-ray diffraction. The crystals either belong to space group P3{sub 1}21 or P3{sub 1} with pseudo P3{sub 1}21 symmetry, with unit-cell parameters a = 51.7, b = 51.7, c = 200.6 Å, α = β = 90, γ = 120°, and diffract X-rays to 3.0 Å resolution. The calculated Matthews number is 1.9 Å{sup 3} Da{sup −1}, with two monomers of molecular weight ∼83 kDa in the asymmetric unit. The molecular- replacement packing solution shows that the molecules form dimers by a domain-swapping mechanism.

  7. Na+/HCO3-共转运体NBCe1的生理及病理学作用%Physiology and pathophysiology of Na+/HCO3-cotransporter NBCe1

    Institute of Scientific and Technical Information of China (English)

    刘颖; 卢群伟; 陈历明

    2012-01-01

    Na+/HCO3- cotransporter NBCe1 is an electrogenic member of the solute carrier 4 (SLC4) family and plays important roles in intracellular pH regulation as well as transepithelial HCO3- movement. The physiological and pathological significance of NBCel has been well established by genetic studies with humans as well as knock-out study with mouse. NBCel is expressed in diverse tissues in mammals. The transporter plays an essential role in the maintenance of acid-base homeostasis in our body, being responsible for more -80% of HCO3- reabsorption in the proximal renal tubule. In humans, a number of SLC4A4 mutations have been associated with proximal renal tubule acidosis that is often accompanied with short stature, ocular abnormalities (including cataract, glaucoma, and band keratopathy), migraine, and/or defects in dental enamel development. In the present article, we review the molecular physiology, the structure/function relationship, the mechanisms underlying the functional regulation of NBCel, as well as the physiological and pathological roles of the transporter.%维持机体的酸碱稳态对各项生理活动的有序进行具有根本性的意义,酸碱紊乱会导致一系列疾病.碳酸氢根(HCO3-)是机体中最重要的酸碱缓冲离子.SLC4家族的HCO3-跨膜转运体是机体最主要的HCO3-跨膜运输载体之一,在细胞的pH调控以及上皮细胞中HCO3-的吸收或分泌过程中起着非常重要的作用.SLC4家族的NBCe1(SLC4A4)是一个生电型的Na+/HCO3-共转运体,在各种组织中有着非常广泛的表达,具有极其重要的生理学作用.在肾脏近端肾小管中,NBCe1负责80%以上的HCO3的重吸收,对于维持机体全局的酸碱平衡极其重要.人类的SLC4A4突变常导致严重的近端肾小管性酸中毒,且常伴有侏儒症、偏头疼、白内障、青光眼以及牙齿釉质发育异常等.本文对最近十多年来有关NBCe1的结构-功能关系、功能调控机制、NBCe1的生理及病理学

  8. Preliminary X-ray Diffraction Analysis of the Cytoplasmic N-terminal Domain of the Na/HCO3 Cotransporter NBCe1-A

    Energy Technology Data Exchange (ETDEWEB)

    Gill,H.; Boron, W.

    2006-01-01

    The N-terminal cytoplasmic domain of the Na{sup +}-coupled HCO{sub 3}{sup -} cotransporter NBCe1-A (NtNBCe1) has been linked with proximal renal tubular acidosis. In a previous purification study of recombinant NtNBCe1, crystal growth at a suboptimal protein concentration (<1 mg ml{sup -1}) yielded small single diamond-shaped crystals that diffracted poorly. In the present study, by increasing the protein concentration 50-fold, the crystal size was doubled and robustness was also improved. Crystal annealing made the crystals suitable for X-ray diffraction. The crystals either belong to space group P3121 or P31 with pseudo P3121 symmetry, with unit-cell parameters a = 51.7, b = 51.7, c = 200.6 Angstroms, {alpha} = {beta} = 90, {gamma} = 120 deg, and diffract X-rays to 3.0 Angstroms resolution. The calculated Matthews number is 1.9 Angstroms{sup 3} Da{sup -1}, with two monomers of molecular weight {approx}83 kDa in the asymmetric unit. The molecular- replacement packing solution shows that the molecules form dimers by a domain-swapping mechanism.

  9. Rescue of the temperature-sensitive, autosomal-recessive mutation R298S in the sodium-bicarbonate cotransporter NBCe1-A characterized by a weakened dimer and abnormal aggregation

    Science.gov (United States)

    Gill, Harindarpal S.; Choi, Kun-Young; Kammili, Lakshmi; Popratiloff, Anastas

    2015-01-01

    Background Band keratopathy, an ocular disease that is characterized by hypercalcemia and opaque bands across the cornea, has been associated with kidney disease. Type-II renal tubular acidosis (RTA), a condition in which the kidneys fail to recover bicarbonate (HCO3−) in the proximal tubule of the nephron, results in HCO3− wastage in the urine and low blood pH. The development of these diseases is associated with autosomal-recessive mutations in the Na+-coupled HCO3− cotransporter NBCe1-A located at the basolateral membranes of either cell type. Methods We provide insight into the devastating R298S mutation found in type-II RTA-afflicted individuals using confocal-microscopy imaging of fluorescently-tagged NBCe1-A and NBCe1-A-R298S molecules expressed in human corneal endothelial and proximal tubule cells and from in-depth biophysical studies of their cytoplasmic N-terminal domains (Nt and Nt-R298S), including Nt crystal structure, melting-temperature, and homodimer dissociation constant (KD) analyses. Results We illuminate and rescue trafficking defects of the R298S mutation of NBCe1-A. The KD for Nt monomer-dimer equilibrium is established. The KD for Nt-R298S is significantly higher, but immeasurable due to environmental factors (pH, temperature, concentration) that result in dimer instability leading to precipitation. The crystal structure of Nt-dimer shows that R298 is part of a putative substrate conduit and resides near the dimer interface held together by hydrogen-bond networks. Conclusions The R298S is a temperature-sensitive mutation in Nt that results in instability of the colloidal system leading to abnormal aggregation. General significance Our findings provide new perspectives to the aberrant mechanism of certain ocular pathologies and type-II RTA associated with the R298S mutation. PMID:25743102

  10. Defective small intestinal anion secretion, dipeptide absorption, and intestinal failure in suckling NBCe1-deficient mice.

    Science.gov (United States)

    Yu, Qin; Liu, Xuemei; Liu, Yongjian; Riederer, Brigitte; Li, Taolang; Tian, De-An; Tuo, Biguang; Shull, Gary; Seidler, Ursula

    2016-08-01

    The electrogenic Na(+)HCO3 (-) cotransporter NBCe1 (Slc4a4) is strongly expressed in the basolateral enterocyte membrane in a villous/surface predominant fashion. In order to better understand its physiological function in the intestine, isolated mucosae in miniaturized Ussing chambers and microdissected intestinal villi or crypts loaded with the fluorescent pH-indicator BCECF were studied from the duodenum, jejunum, and colon of 14- to 17-days-old slc4a4-deficient (KO) and WT mice. NBCe1 was active in the basal state in all intestinal segments under study, most likely to compensate for acid loads imposed upon the enterocytes. Upregulation of other basolateral base uptake mechanism occurs, but in a segment-specific fashion. Loss of NBCe1 resulted in severely impaired Cl(-) and fluid secretory response, but not HCO3 (-) secretory response to agonist stimulation. In addition, NBCe1 was found to be active during transport processes that load the surface enterocytes with acid, such as Slc26a3 (DRA)-mediated luminal Cl(-)/HCO3 (-) exchange or PEPT1-mediated H(+)/dipeptide uptake. Possibly because of the high energy demand for hyperventilation in conjunction with the fluid secretory and nutrient absorptive defects and the relative scarcity of compensatory mechanisms, NBCe1-deficient mice developed progressive jejunal failure, worsening of metabolic acidosis, and death in the third week of life. Our data suggest that the electrogenic influx of base via NBCe1 maintains enterocyte anion homeostasis and pHi control. Its loss impairs small intestinal Cl(-) and fluid secretion as well as the neutralization of acid loads imposed on the enterocytes during nutrient and electrolyte absorption.

  11. Interaction between cAMP, volume‑regulated anion channels and the Na+‑HCO3‑‑cotransporter, NBCe1, in the regulation of nutrient‑ and hypotonicity‑induced insulin release from isolated rat pancreatic islets and tumoral insulin‑producing BRIN‑BD11 cells.

    Science.gov (United States)

    Bulur, Nurdan; Crutzen, Raphael; Malaisse, Willy J; Sener, Abdullah; Beauwens, Renaud; Golstein, Philippe

    2013-05-01

    Soluble adenylyl cyclase (sAC) has been hypothesized to play a role in insulin secretion. The present study aimed to investigate the interaction between adenosine 3',5'‑cyclic monophosphate (cAMP), volume‑regulated anion channels (VRACs) and the electrogenic sodium bicarbonate (Na+‑HCO3‑) cotransporter, NBCe1, in the regulation of nutrient‑ and hypotonicity‑induced insulin release from rat pancreatic islets and tumoral insulin‑producing BRIN‑BD11 cells. In the islets, 5‑nitro‑2‑(3‑phenylpropylamino)benzoic acid (NPPB) and 5‑chloro‑2‑hydroxy‑3‑(thiophene‑2‑carbonyl)indole‑1‑carboxamide (tenidap) reduced glucose‑stimulated insulin release, however, only NPPB suppressed the enhancing action of cAMP analogs upon such a release. Insulin output from the BRIN‑BD11 cells was stimulated by 2‑ketoisocaproate (KIC) or extracellular hypoosmolarity. cAMP analogs and 3‑isobutyl‑1‑methylxanthine increased the insulin output recorded in the isotonic medium to a greater relative extent than that in the hypotonic medium. The secretory response to KIC or hypotonicity was inhibited by NPPB or tenidap, which both also opposed the enhancing action of cAMP analogs. Inhibitors of mitogen‑activated protein (MAP) kinase decreased insulin output in isotonic and hypotonic media. The inhibitor of sAC, 2‑hydroxyestriol, caused only a modest inhibition of insulin release, whether in the isotonic or hypotonic medium, even when tested at a concentration of 100 µM. The omission of NaHCO3 markedly decreased the secretory response to KIC or extracellular hypotonicity. The omission of Na+ suppressed the secretory response to extracellular hypotonicity. The observations of the present study do not support the hypothesis of a major role for sAC in the regulation of insulin release.

  12. Carbonic anhydrase II increases the activity of the human electrogenic Na+/HCO3- cotransporter.

    Science.gov (United States)

    Becker, Holger M; Deitmer, Joachim W

    2007-05-04

    Several acid/base-coupled membrane transporters, such as the electrogenic sodium-bicarbonate cotransporter (NBCe1), have been shown to bind to different carbonic anhydrase isoforms to create a "transport metabolon." We have expressed NBCe1 derived from human kidney in oocytes of Xenopus leavis and determined its transport activity by recording the membrane current in voltage clamp, and the cytosolic H(+) and Na(+) concentrations using ion-selective microelectrodes. When carbonic anhydrase isoform II (CAII) had been injected into oocytes, the membrane current and the rate of cytosolic Na(+) rise, indicative for NBCe1 activity, increased significantly with the amount of injected CAII (2-200 ng). The CAII inhibitor ethoxyzolamide reversed the effects of CAII on the NBCe1 activity. Co-expressing wild-type CAII or NH(2)-terminal mutant CAII together with NBCe1 provided similar results, whereas co-expressing the catalytically inactive CAII mutant V143Y had no effect on NBCe1 activity. Mass spectrometric analysis and the rate of cytosolic H(+) change following addition of CO(2)/HCO(3)(-) confirmed the catalytic activity of injected and expressed CAII in oocytes. Our results show that the transport capacity of NBCe1 is enhanced by the catalytic activity of CAII, in line with the notion that CAII forms a transport metabolon with NBCe1.

  13. The role of aspartic acid residues 405 and 416 of the kidney isotype of sodium-bicarbonate cotransporter 1 in its targeting to the plasma membrane

    Science.gov (United States)

    Kucher, Volodymyr; Li, Emily Y.; Conforti, Laura; Zahedi, Kamyar A.

    2012-01-01

    The NH2 terminus of the sodium-bicarbonate cotransporter 1 (NBCe1) plays an important role in its targeting to the plasma membrane. To identify the amino acid residues that contribute to the targeting of NBCe1 to the plasma membrane, polarized MDCK cells were transfected with expression constructs coding for green fluorescent protein (GFP)-tagged NBCe1 NH2-terminal deletion mutants, and the localization of GFP-tagged proteins was analyzed by confocal microscopy. Our results indicate that the amino acids between residues 399 and 424 of NBCe1A contain important sequences that contribute to its localization to the plasma membrane. Site-directed mutagenesis studies showed that GFP-NBCe1A mutants D405A and D416A are retained in the cytoplasm of the polarized MDCK epithelial cells. Examination of functional activities of D405A and D416A reveals that their activities are reduced compared with the wild-type NBCe1A. Similarly, aspartic acid residues 449 and 460 of pancreatic NBCe1 (NBCe1B), which correspond to residues 405 and 416 of NBCe1A, are also required for its full functional activity and accurate targeting to the plasma membrane. In addition, while replacement of D416 with glutamic acid did not affect the targeting or functional activity of NBCe1A, substitution of D405 with glutamic acid led to the retention of the mutated protein in the intracellular compartment and impaired functional activity. These studies demonstrate that aspartic acid residues 405 and 416 in the NH2 terminus of NBCe1A are important in its accurate targeting to the plasma membrane. PMID:22442137

  14. Ahcyl2 upregulates NBCe1-B via multiple serine residues of the PEST domain-mediated association.

    Science.gov (United States)

    Park, Pil Whan; Ahn, Jeong Yeal; Yang, Dongki

    2016-07-01

    Inositol-1,4,5-triphosphate [IP3] receptors binding protein released with IP3 (IRBIT) was previously reported as an activator of NBCe1-B. Recent studies have characterized IRBIT homologue S-Adenosylhomocysteine hydrolase-like 2 (AHCYL2). AHCYL2 is highly homologous to IRBIT (88%) and heteromerizes with IRBIT. The two important domains in the N-terminus of AHCYL2 are a PEST domain and a coiled-coil domain which are highly comparable to those in IRBIT. Therefore, in this study, we tried to identify the role of those domains in mouse AHCYL2 (Ahcyl2), and we succeeded in identifying PEST domain of Ahcyl2 as a regulation region for NBCe1-B activity. Site directed mutagenesis and coimmunoprecipitation assay showed that NBCe1-B binds to the N-terminal Ahcyl2-PEST domain, and its binding is determined by the phosphorylation of 4 critical serine residues (Ser151, Ser154, Ser157, and Ser160) in Ahcyl2 PEST domain. Also we revealed that 4 critical serine residues in Ahcyl2 PEST domain are indispensable for the activation of NBCe1-B using measurement of intracellular pH experiment. Thus, these results suggested that the NBCe1-B is interacted with 4 critical serine residues in Ahcyl2 PEST domain, which play an important role in intracellular pH regulation through NBCe1-B.

  15. Alternative splice variant of the thiazide-sensitive NaCl cotransporter

    DEFF Research Database (Denmark)

    Tutakhel, Omar A Z; Jeleń, Sabina; Valdez-Flores, Marco;

    2016-01-01

    The thiazide-sensitive NaCl cotransporter (NCC) is an important pharmacological target in the treatment of hypertension. Human SLC12A3 gene, encoding NCC, gives rise to three isoforms. Only the 3(rd) isoform has been extensively investigated. The aim of the present study was, therefore, to establ...

  16. The Renal Sodium Bicarbonate Cotransporter NBCe2: Is It a Major Contributor to Sodium and pH Homeostasis?

    Science.gov (United States)

    Felder, Robin A; Jose, Pedro A; Xu, Peng; Gildea, John J

    2016-09-01

    The sodium bicarbonate cotransporter (NBCe2, aka NBC4) was originally isolated from the human testis and heart (Pushkin et al. IUBMB Life 50:13-19, 2000). Subsequently, NBCe2 was found in diverse locations where it plays a role in regulating sodium and bicarbonate transport, influencing intracellular, extracellular, interstitial, and ultimately plasma pH (Boron et al. J Exp Biol. 212:1697-1706, 2009; Parker and Boron, Physiol Rev. 93:803-959, 2013; Romero et al. Mol Asp Med. 34:159-182, 2013). NBCe2 is located in human and rodent renal-collecting duct and proximal tubule. While much is known about the two electrogenic sodium bicarbonate cotransporters, NBCe1 and NBCe2, in the regulation of sodium homeostasis and pH balance in the rodent kidney, little is known about their roles in human renal physiology. NBCe2 is located in the proximal tubule Golgi apparatus under basal conditions and then disperses throughout the cell, but particularly into the apical membrane microvilli, during various maneuvers that increase intracellular sodium. This review will summarize our current understanding of the distribution and function of NBCe2 in the human kidney and how genetic variants of its gene, SLC4A5, contribute to salt sensitivity of blood pressure.

  17. Novel molecular variants of the Na-Cl cotransporter gene are responsible for Gitelman syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Mastroianni, N.; De Fusco, M.; Casari, G. [Univsersita` di Milano (Italy)] [and others

    1996-11-01

    A hereditary defect of the distal tubule accounts for the clinical features of Gitelman syndrome (GS), an autosomal recessive disease characterized by hypokalemia, hypomagnesemia, metabolic alkalosis, and hypocalciuria. Recently, we cloned the cDNA coding for the human Na-Cl thiazide-sensitive cotransporter (TSC; also known as {open_quotes}NCCT{close_quotes} or {open_quotes}SLC12A3{close_quotes}) as a possible candidate for GS, and Simon et al., independently, described rotation in patients with GS. Now, we show 12 additional mutations consistent with a loss of function of the Na-Cl cotransporter in GS. Two missense replacements, R09W and P349L, are common to both studies and could represent ancient mutations. The other mutations include three deletions, two insertions, and six missense mutations. When all mutations from both studies are considered, missense mutations seem to be more frequently localized within the intracellular domains of the molecule, rather than in transmembrane or extracellular domains. One family, previously reported as a GS form with dominant inheritance, has proved to be recessive, with the affected child being a compound heterozygote. A highly informative intragenic tetranucleotide marker, useful for molecular diagnostic studies, has been identified at the acceptor splice site of exon 9. 12 refs., 3 figs., 2 tabs.

  18. Sodium-glucose cotransport

    Science.gov (United States)

    Poulsen, Søren Brandt; Fenton, Robert A.; Rieg, Timo

    2017-01-01

    Purpose of review Sodium-glucose cotransporters (SGLTs) are important mediators of glucose uptake across apical cell membranes. SGLT1 mediates almost all sodium-dependent glucose uptake in the small intestine, while in the kidney SGLT2, and to a lesser extent SGLT1, account for more than 90% and nearly 3%, respectively, of glucose reabsorption from the glomerular ultrafiltrate. Although the recent availability of SGLT2 inhibitors for the treatment of diabetes mellitus has increased the number of clinical studies, this review has a focus on mechanisms contributing to the cellular regulation of SGLTs. Recent findings Studies have focused on the regulation of SGLT expression under different physiological/pathophysiological conditions, for example diet, age or diabetes mellitus. Several studies provide evidence of SGLT regulation via cyclic adenosine monophosphate/protein kinase A, protein kinase C, glucagon-like peptide 2, insulin, leptin, signal transducer and activator of transcription-3 (STAT3), phosphoinositide-3 kinase (PI3K)/Akt, mitogen-activated protein kinases (MAPKs), nuclear factor-kappaB (NF-kappaB), with-no-K[Lys] kinases/STE20/SPS1-related proline/alanine-rich kinase (Wnk/SPAK) and regulatory solute carrier protein 1 (RS1) pathways. Summary SGLT inhibitors are important drugs for glycemic control in diabetes mellitus. Although the contribution of SGLT1 for absorption of glucose from the intestine as well as SGLT2/SGLT1 for renal glucose reabsorption has been comprehensively defined, this review provides an up-to-date outline for the mechanistic regulation of SGLT1/SGLT2. PMID:26125647

  19. Cotransporters as molecular water pumps

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; MacAulay, Nanna

    2002-01-01

    Molecular water pumps are membrane proteins of the cotransport type in which a flux of water is coupled to substrate fluxes by a mechanism within the protein. Free energy can be exchanged between the fluxes. Accordingly, the flux of water may be relatively independent of the external water chemical...

  20. Passive water and ion transport by cotransporters

    DEFF Research Database (Denmark)

    Loo, D D; Hirayama, B A; Meinild, A K

    1999-01-01

    1. The rabbit Na+-glucose (SGLT1) and the human Na+-Cl--GABA (GAT1) cotransporters were expressed in Xenopus laevis oocytes, and passive Na+ and water transport were studied using electrical and optical techniques. Passive water permeabilities (Lp) of the cotransporters were determined from...... the changes in oocyte volume in response to osmotic gradients. The specific SGLT1 and GAT1 Lp values were obtained by measuring Lp in the presence and absence of blockers (phlorizin and SKF89976A). In the presence of the blockers, the Lp values of oocytes expressing SGLT1 and GAT1 were indistinguishable from...... the Lp of control oocytes. Passive Na+ transport (Na+ leak) was obtained from the blocker-sensitive Na+ currents in the absence of substrates (glucose and GABA). 2. Passive Na+ and water transport through SGLT1 were blocked by phlorizin with the same sensitivity (inhibitory constant (Ki), 3-5 micro...

  1. Ovarian hormones and prolactin increase renal NaCl cotransporter phosphorylation.

    Science.gov (United States)

    Rojas-Vega, Lorena; Reyes-Castro, Luis A; Ramírez, Victoria; Bautista-Pérez, Rocío; Rafael, Chloe; Castañeda-Bueno, María; Meade, Patricia; de Los Heros, Paola; Arroyo-Garza, Isidora; Bernard, Valérie; Binart, Nadine; Bobadilla, Norma A; Hadchouel, Juliette; Zambrano, Elena; Gamba, Gerardo

    2015-04-15

    Unique situations in female physiology require volume retention. Accordingly, a dimorphic regulation of the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) has been reported, with a higher activity in females than in males. However, little is known about the hormones and mechanisms involved. Here, we present evidence that estrogens, progesterone, and prolactin stimulate NCC expression and phosphorylation. The sex difference in NCC abundance, however, is species dependent. In rats, NCC phosphorylation is higher in females than in males, while in mice both NCC expression and phosphorylation is higher in females, and this is associated with increased expression and phosphorylation of full-length STE-20 proline-alanine-rich kinase (SPAK). Higher expression/phosphorylation of NCC was corroborated in humans by urinary exosome analysis. Ovariectomy in rats resulted in decreased expression and phosphorylation of the cotransporter and promoted the shift of SPAK isoforms toward the short inhibitory variant SPAK2. Conversely, estradiol or progesterone administration to ovariectomized rats restored NCC phosphorylation levels and shifted SPAK expression and phosphorylation towards the full-length isoform. Estradiol administration to male rats induced a significant increase in NCC phosphorylation. NCC is also modulated by prolactin. Administration of this peptide hormone to male rats induced increased phosphorylation of NCC, an effect that was observed even using the ex vivo kidney perfusion strategy. Our results indicate that estradiol, progesterone, and prolactin, the hormones that are involved in sexual cycle, pregnancy and lactation, upregulate the activity of NCC.

  2. Water transport by the renal Na(+)-dicarboxylate cotransporter

    DEFF Research Database (Denmark)

    Meinild, A K; Loo, D D; Pajor, A M;

    2000-01-01

    This study investigated the ability of the renal Na(+)-dicarboxylate cotransporter, NaDC-1, to transport water. Rabbit NaDC-1 was expressed in Xenopus laevis oocytes, cotransporter activity was measured as the inward current generated by substrate (citrate or succinate), and water transport...... was monitored by the changes in oocyte volume. In the absence of substrates, oocytes expressing NaDC-1 showed an increase in osmotic water permeability, which was directly correlated with the expression level of NaDC-1. When NaDC-1 was transporting substrates, there was a concomitant increase in oocyte volume....... This solute-coupled influx of water took place in the absence of, and even against, osmotic gradients. There was a strict stoichiometric relationship between Na(+), substrate, and water transport of 3 Na(+), 1 dicarboxylate, and 176 water molecules/transport cycle. These results indicate that the renal Na...

  3. Water transport by the renal Na(+)-dicarboxylate cotransporter

    DEFF Research Database (Denmark)

    Meinild, A K; Loo, D D; Pajor, A M

    2000-01-01

    was monitored by the changes in oocyte volume. In the absence of substrates, oocytes expressing NaDC-1 showed an increase in osmotic water permeability, which was directly correlated with the expression level of NaDC-1. When NaDC-1 was transporting substrates, there was a concomitant increase in oocyte volume....... This solute-coupled influx of water took place in the absence of, and even against, osmotic gradients. There was a strict stoichiometric relationship between Na(+), substrate, and water transport of 3 Na(+), 1 dicarboxylate, and 176 water molecules/transport cycle. These results indicate that the renal Na......This study investigated the ability of the renal Na(+)-dicarboxylate cotransporter, NaDC-1, to transport water. Rabbit NaDC-1 was expressed in Xenopus laevis oocytes, cotransporter activity was measured as the inward current generated by substrate (citrate or succinate), and water transport...

  4. Inhibition of Na(+)-K(+)-2Cl(-) cotransport by mercury.

    Science.gov (United States)

    Jacoby, S C; Gagnon, E; Caron, L; Chang, J; Isenring, P

    1999-10-01

    Mercury alters the function of proteins by reacting with cysteinyl sulfhydryl (SH(-)) groups. The inorganic form (Hg(2+)) is toxic to epithelial tissues and interacts with various transport proteins including the Na(+) pump and Cl(-) channels. In this study, we determined whether the Na(+)-K(+)-Cl(-) cotransporter type 1 (NKCC1), a major ion pathway in secretory tissues, is also affected by mercurial substrates. To characterize the interaction, we measured the effect of Hg(2+) on ion transport by the secretory shark and human cotransporters expressed in HEK-293 cells. Our studies show that Hg(2+) inhibits Na(+)-K(+)-Cl(-) cotransport, with inhibitor constant (K(i)) values of 25 microM for the shark carrier (sNKCC1) and 43 microM for the human carrier. In further studies, we took advantage of species differences in Hg(2+) affinity to identify residues involved in the interaction. An analysis of human-shark chimeras and of an sNKCC1 mutant (Cys-697-->Leu) reveals that transmembrane domain 11 plays an essential role in Hg(2+) binding. We also show that modification of additional SH(-) groups by thiol-reacting compounds brings about inhibition and that the binding sites are not exposed on the extracellular face of the membrane.

  5. Cellulase variants

    Energy Technology Data Exchange (ETDEWEB)

    Blazej, Robert; Toriello, Nicholas; Emrich, Charles; Cohen, Richard N.; Koppel, Nitzan

    2015-07-14

    This invention provides novel variant cellulolytic enzymes having improved activity and/or stability. In certain embodiments the variant cellulotyic enzymes comprise a glycoside hydrolase with or comprising a substitution at one or more positions corresponding to one or more of residues F64, A226, and/or E246 in Thermobifida fusca Cel9A enzyme. In certain embodiments the glycoside hydrolase is a variant of a family 9 glycoside hydrolase. In certain embodiments the glycoside hydrolase is a variant of a theme B family 9 glycoside hydrolase.

  6. Water transport between CNS compartments: contributions of aquaporins and cotransporters

    DEFF Research Database (Denmark)

    MacAulay, N; Zeuthen, T

    2010-01-01

    review we introduce another family of transport proteins as water transporters, namely the cotransporters and the glucose uniport GLUT1. In direct contrast to the aquaporins, these proteins have an inherent ability to transport water against an osmotic gradient. Some of them may also function as water...... or hydrocephalus. The molecular pathways by which water molecules cross the cell membranes of the brain are not well-understood, although the discovery of aquaporin 4 (AQP4) in the brain improved our understanding of some of these transport processes, particularly under pathological conditions. In the present...

  7. Salt sensitivity of blood pressure is associated with polymorphisms in the sodium-bicarbonate cotransporter.

    Science.gov (United States)

    Carey, Robert M; Schoeffel, Cynthia D; Gildea, John J; Jones, John E; McGrath, Helen E; Gordon, Lindsay N; Park, Min Jeong; Sobota, Rafal S; Underwood, Patricia C; Williams, Jonathan; Sun, Bei; Raby, Benjamin; Lasky-Su, Jessica; Hopkins, Paul N; Adler, Gail K; Williams, Scott M; Jose, Pedro A; Felder, Robin A

    2012-11-01

    Previous studies have demonstrated that single nucleotide polymorphisms (SNPs) of the sodium-bicarbonate co-transporter gene (SLC4A5) are associated with hypertension. We tested the hypothesis that SNPs in SLC4A5 are associated with salt sensitivity of blood pressure in 185 whites consuming an isocaloric constant diet with a randomized order of 7 days of low Na(+) (10 mmol/d) and 7 days of high Na(+) (300 mmol/d) intake. Salt sensitivity was defined as a ≥ 7-mm Hg increase in mean arterial pressure during a randomized transition between high and low Na(+) diet. A total of 35 polymorphisms in 17 candidate genes were assayed, 25 of which were tested for association. Association analyses with salt sensitivity revealed 3 variants that associated with salt sensitivity, 2 in SLC4A5 (P<0.001) and 1 in GRK4 (P=0.020). Of these, 2 SNPs in SLC4A5 (rs7571842 and rs10177833) demonstrated highly significant results and large effects sizes, using logistic regression. These 2 SNPs had P values of 1.0 × 10(-4) and 3.1 × 10(-4) with odds ratios of 0.221 and 0.221 in unadjusted regression models, respectively, with the G allele at both sites conferring protection. These SNPs remained significant after adjusting for body mass index and age (P=8.9 × 10(-5) and 2.6 × 10(-4) and odds ratios 0.210 and 0.286, respectively). Furthermore, the association of these SNPs with salt sensitivity was replicated in a second hypertensive population. Meta-analysis demonstrated significant associations of both SNPs with salt sensitivity (rs7571842 [P=1.2 × 10(-5)]; rs1017783 [P=1.1 × 10(-4)]). In conclusion, SLC4A5 variants are strongly associated with salt sensitivity of blood pressure in 2 separate white populations.

  8. Inflammatory cytokine TNF-α inhibits Na(+)-glutamine cotransport in intestinal epithelial cells.

    Science.gov (United States)

    Talukder, Jamilur R; Boyd, Brittney; Griffin, Ashley; Jaima, Antara; Rajendran, Vazhaikkurichi M

    2013-04-01

    Glutamine (Gln), a preferred fuel source for enterocytes, is critical for intestinal epithelial cell integrity and barrier function. Chronic enteritis inhibits apical Na(+)-Gln cotransport. It is not known whether inflammatory cytokines that are secreted during inflammation inhibit Na(+)-Gln cotransport. Thus, this study aimed to examine whether TNF-α would affect apical Na(+)-Gln cotransport in intestinal epithelial cells. In this study, the presence of Na(+)-Gln cotransport was established by measuring Gln uptake in 10 days postconfluent IEC-6 cells grown on transwell plates. Cation, amino acid specificity, and siRNA transfection studies established that Na(+)-Gln cotransport is mediated via B(0)AT1. Immunoblotting and immunofluorescence studies established the apical membrane localization of B(0)AT1 in IEC-6 cells. Tumour necrosis factor α (TNF-α) inhibited Na(+)-Gln cotransport in a concentration- and time-dependent manner with an inhibitory concentration of 1.53 nmol·L(-1). Quantitative real-time PCR and Western blot analyses indicated that TNF-α did not alter B(0)AT1-specific transcripts or protein expression level. Kinetic studies revealed that TNF-α inhibited Na(+)-Gln cotransport by reducing the affinity of the cotransporters for Gln, and this effect was antagonized by genistein. Thus, we conclude that the TNF-α inhibition of Na(+)-Gln cotransport occurs at the post-translational level, and that the IEC-6 cell line is an excellent system to study the role of cytokines in Na(+)-Gln cotransport.

  9. The clinical significance of K-Cl cotransport activity in red cells of patients with HbSC disease.

    Science.gov (United States)

    Rees, David C; Thein, Swee Lay; Osei, Anna; Drasar, Emma; Tewari, Sanjay; Hannemann, Anke; Gibson, John S

    2015-05-01

    HbSC disease is the second commonest form of sickle cell disease, with poorly understood pathophysiology and few treatments. We studied the role of K-Cl cotransport activity in determining clinical and laboratory features, and investigated its potential role as a biomarker. Samples were collected from 110 patients with HbSC disease and 41 with sickle cell anemia (HbSS). K-Cl cotransport activity was measured in the oxygenated (K-Cl cotransport(100)) and deoxygenated (K-Cl cotransport(0)) states, using radioactive tracer studies. K-Cl cotransport activity was high in HbSC and decreased significantly on deoxygenation. K-Cl cotransport activity correlated significantly and positively with the formation of sickle cells. On multiple regression analysis, K-Cl cotransport increased significantly and independently with increasing reticulocyte count and age. K-Cl cotransport activity was increased in patients who attended hospital with acute pain in 2011 compared to those who did not (K-Cl cotransport(100): mean 3.87 versus 3.20, P=0.009, independent samples T-test; K-Cl cotransport(0): mean 0.96 versus 0.68, P=0.037). On logistic regression only K-Cl cotransport was associated with hospital attendance. Increased K-Cl cotransport activity was associated with the presence of retinopathy, but this effect was confounded by age. This study links variability in a fundamental aspect of cellular pathology with a clinical outcome, suggesting that K-Cl cotransport is central to the pathology of HbSC disease. Increased K-Cl cotransport activity is associated with increasing age, which may be of pathophysiological significance. Effective inhibition of K-Cl cotransport activity is likely to be of therapeutic benefit.

  10. WNK kinases regulate thiazide-sensitive Na-Cl cotransport.

    Science.gov (United States)

    Yang, Chao-Ling; Angell, Jordan; Mitchell, Rose; Ellison, David H

    2003-04-01

    Pseudohypoaldosteronism type II (PHAII) is an autosomal dominant disorder of hyperkalemia and hypertension. Mutations in two members of the WNK kinase family, WNK1 and WNK4, cause the disease. WNK1 mutations are believed to increase WNK1 expression; the effect of WNK4 mutations remains unknown. The clinical phenotype of PHAII is opposite to Gitelman syndrome, a disease caused by dysfunction of the thiazide-sensitive Na-Cl cotransporter. We tested the hypothesis that WNK kinases regulate the mammalian thiazide-sensitive Na-Cl cotransporter (NCC). Mouse WNK4 was cloned and expressed in Xenopus oocytes with or without NCC. Coexpression with WNK4 suppressed NCC activity by more than 85%. This effect did not result from defects in NCC synthesis or processing, but was associated with an 85% reduction in NCC abundance at the plasma membrane. Unlike WNK4, WNK1 did not affect NCC activity directly. WNK1, however, completely prevented WNK4 inhibition of NCC. Some WNK4 mutations that cause PHAII retained NCC-inhibiting activity, but the Q562E WNK4 demonstrated diminished activity, suggesting that some PHAII mutations lead to loss of NCC inhibition. Gain-of-function WNK1 mutations would be expected to inhibit WNK4 activity, thereby activating NCC, contributing to the PHAII phenotype. Together, these results identify WNK kinases as a previously unrecognized sodium regulatory pathway of the distal nephron. This pathway likely contributes to normal and pathological blood pressure homeostasis.

  11. Exploring the intricate regulatory network controlling the thiazide-sensitive NaCl cotransporter (NCC)

    DEFF Research Database (Denmark)

    Dimke, Henrik Anthony

    2011-01-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays key roles in renal electrolyte transport and blood pressure maintenance. Regulation of this cotransporter has received increased attention recently, prompted by the discovery that mutations in the with-no-lysine (WNK) kinases are the molecular...... by acting as a scaffold between the dephosphorylated cotransporter and the regulatory kinase. As more molecular regulators of NCC are identified, the system-controlling NCC activity is becoming increasingly complex. This intricacy confers an ability to integrate a variety of stimuli, thereby regulating NCC...

  12. Analgesic effect of intrathecal bumetanide is accompanied by changes in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain

    Institute of Scientific and Technical Information of China (English)

    Yanbing He; Shiyuan Xu; Junjie Huang; Qingjuan Gong

    2014-01-01

    Accumulating evidence has demonstrated that the sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 have a role in the modulation of pain transmission at the spinal level through chloride regulation in the pain pathway and by effecting neuronal excitability and pain sensitization. The present study aimed to investigate the analgesic effect of the speciifc sodium-potassium-chloride co-transporter 1 inhibitor bumetanide, and the change in spinal sodium-potassium-chloride co-transporter 1 and potassium-chloride co-transporter 2 expression in a rat model of incisional pain. Results showed that intrathecal bumetanide could decrease cumulative pain scores, and could increase thermal and mechanical pain thresholds in a rat model of incisional pain. Sodium-potassium-chloride co-transporter 1 expression in-creased in neurons from dorsal root ganglion and the deep laminae of the ipsilateral dorsal horn following incision. By contrast, potassium-chloride co-transporter 2 expression decreased in neurons of the deep laminae from the ipsilateral dorsal horn. These ifndings suggest that spinal sodium-potassium-chloride co-transporter 1 expression was up-regulated and spinal potassi-um-chloride co-transporter 2 expression was down-regulated following incision. Intrathecal bumetanide has analgesic effects on incisional pain through inhibition of sodium-potassi-um-chloride co-transporter 1.

  13. Structural and functional significance of water permeation through cotransporters

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Gorraitz, Edurne; Her, Ka

    2016-01-01

    and mutated residues lining the sugar transport pathway to cysteine. The mutants were expressed in Xenopus oocytes, and the unitary water and urea permeabilities were determined before and after modifying the cysteine side chain with reversible methanethiosulfonate reagents. The results demonstrate that water......Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea...... through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na+ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified...

  14. The Electrogenic Na+/HCO3- Cotransporter, NBC

    Directory of Open Access Journals (Sweden)

    Romero MF

    2001-07-01

    Full Text Available Electrogenic Na(+/HCO(3(- (NBC function has been characterized in many mammalian tissues including, kidney, pancreas, and brain. Cloning efforts identified a single cDNA, NBC/NBC1, that possesses all the functional attributes of the electrogenic Na(+/HCO(3(- cotransporter. This NBC clone is related to the anion exchangers and thus forms a bicarbonate transporter superfamily. Presently two N-terminal and one C-terminal isoforms are known. All three isoforms appear to arise from the same gene and seem to have identical function. NBC antibodies have localized NBC isoforms in kidney, pancreas, brain, small intestine, colon, epididymis, eye, heart, liver, salivary glands, stomach, and testis. Functionally, NBC appears HCO(3(- and Na(+ selective. NBC stoichiometry in Xenopus oocytes is 1 Na(+ : 2 HCO(3(-, implicating a possible accessory protein interaction.

  15. Water transport by the Na+/glucose cotransporter under isotonic conditions

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Klaerke, D A;

    1997-01-01

    Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed...... in Xenopus oocytes. We present a method which allows short-term exposures to sugar under voltage clamp conditions. We demonstrate that water is cotransported with the solutes despite no osmotic differences between the external and intracellular solutions. There is a fixed ratio of 195:1 between the number...... of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin....

  16. Water permeability of Na+-K+-2C1- cotransporters in mammalian epithelial cells

    DEFF Research Database (Denmark)

    Hammann, Steffen; Herrera-Perez, J.J.; Bundgaard, Magnus

    2005-01-01

    Water transport properties of the Na+-K+-2Cl- cotransporter (NKCC) were studied in cultures of pigmented epithelial cells (PE) from the ciliary body of the eye. Here, the membrane that faces upwards contains NKCCs and can be subjected to rapid changes in bathing solution composition and osmolarity...... changes of the cotransporter and interaction with Na+, K+ and Cl-. Similar measurements were performed on immortalized cell cultures from the thick ascending limb of the loop of Henle (TALH). Given similar overall transport rates of bumetanide-sensitive 86Rb+, the NKCCs of this tissue did not contribute...... any bumetanide-sensitive Lp. This suggests that the cotransporters of the two tissues are either different isoforms or the same cotransporter but in two different transport modes....

  17. Cotransport of water by the Na+-K+-2Cl(-) cotransporter NKCC1 in mammalian epithelial cells

    DEFF Research Database (Denmark)

    Hamann, Steffen; Herrera-Perez, José J; Zeuthen, Thomas

    2010-01-01

    ionic and osmotic gradients. The coupling between salt and water transport in NKCC1 represents a novel aspect of cellular water homeostasis where cells can change their volume independently of the direction of an osmotic gradient across the membrane. This has relevance for both epithelial......Water transport by the Na+-K+-2Cl(-) cotransporter (NKCC1) was studied in confluent cultures of pigmented epithelial (PE) cells from the ciliary body of the fetal human eye. Interdependence among water, Na+ and Cl(-) fluxes mediated by NKCC1 was inferred from changes in cell water volume, monitored...... of external Na+ and Cl(-). The water influx could proceed uphill, against a transmembrane osmotic gradient, suggesting that energy contained in the ion fluxes can be transferred to the water flux. The influx of water induced by changes in external [Cl(-)] saturated in a sigmoidal fashion with a Km of 60 mm...

  18. Cotransport of H+, lactate, and H2O in porcine retinal pigment epithelial cells

    DEFF Research Database (Denmark)

    Hamann, Steffen; Kiilgaard, Jens Folke; la Cour, Morten

    2003-01-01

    ) for the H(+) and lactate fluxes. The data suggest that H(2)O is cotransported along with H(+) and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue...... and supports our previous study performed by an invasive technique in an amphibian tissue....

  19. Establishing a definitive stoichiometry for the Na+/monocarboxylate cotransporter SMCT1.

    Science.gov (United States)

    Coady, Michael J; Wallendorff, Bernadette; Bourgeois, Francis; Charron, Francois; Lapointe, Jean-Yves

    2007-10-01

    Several different stoichiometries have been proposed for the Na(+)/monocarboxylate cotransporter SMCT1, including variable Na(+)/substrate stoichiometry. In this work, we have definitively established an invariant 2:1 cotransport stoichiometry for SMCT1. By using two independent means of assay, we first showed that SMCT1 exhibits a 2:1 stoichiometry for Na(+)/lactate cotransport. Radiolabel uptake experiments proved that, unlike lactate, propionic acid diffuses passively through oocyte membranes and, consequently, propionate is a poor candidate for stoichiometric determination by these methods. Although we previously determined SMCT1 stoichiometry by measuring reversal potentials, this technique produced erroneous values, because SMCT1 simultaneously mediates both an inwardly rectifying cotransport current and an outwardly rectifying anionic leak current; the leak current predominates in the range where reversal potentials are observed. We therefore employed a method that compared the effect of halving the external Na(+) concentration to the effect of halving the external substrate concentration on zero-current potentials. Both lactate and propionate were cotransported through SMCT1 using 2:1 stoichiometries. The leak current passing through the protein has a 1 osmolyte/charge stoichiometry. Identification of cotransporter stoichiometry is not always a trivial task and it can lead to a much better understanding of the transport activity mediated by the protein in question.

  20. Differential expression patterns of chloride transporters, Na+-K+-2Cl--cotransporter and K+-Cl--cotransporter, in epilepsy-associated malformations of cortical development.

    NARCIS (Netherlands)

    Aronica, E.; Boer, K.; Redeker, S.; Spliet, W.G.; van Rijen, P.C.; Troost, D; Gorter, J.A.

    2007-01-01

    Malformations of cortical development are recognized causes of chronic medically intractable epilepsy. An increasing number of observations suggests an important role for cation-chloride co-transporters (CCTs) in controlling neuronal function. Deregulation of their expression may contribute to the

  1. Regulation of renal Na-(K)-Cl cotransporters by vasopressin.

    Science.gov (United States)

    Bachmann, Sebastian; Mutig, Kerim

    2017-08-01

    Vasopressin (AVP) induces antidiuresis, thus playing an essential role in body water and electrolyte homeostasis. Its antidiuretic effects are mediated chiefly by V2 vasopressin receptors (V2R) expressed along the distal nephron and collecting duct epithelia. NaCl reabsorption in the distal nephron, which includes the thick ascending limb (TAL) and distal convoluted tubule (DCT), largely depends on the activity of two structurally related Na-(K)-Cl cotransporters, NKCC2 in TAL and NCC in DCT. AVP-induced activation of these transporters contributes to urine concentration and renal electrolyte reabsorption. Previous work has specified molecular pathways mediating the effects of V2R activation in TAL and DCT, and protein networks involved in intracellular trafficking and phosphoregulation of the two transporters have been identified. This review summarizes recent progress in understanding AVP signalling mechanisms that are responsible for the activation of NKCC2 and NCC. Implications in the pathophysiology of diseases such as nephrogenic diabetes insipidus, diabetes mellitus and salt-sensitive hypertension are discussed in this context.

  2. A novel strategy for the treatment of diabetes mellitus - sodium glucose co-transport inhibitors.

    Science.gov (United States)

    Niazi, Asfandyar Khan; Niazi, Saad Hameed

    2010-12-01

    Diabetes is one of the most common chronic diseases, affecting almost 3 million in Canada alone and is characterized by increased blood glucose levels. Treatment varies from lifestyle changes to oral anti-diabetics and/or insulin. Sodium glucose co-transport inhibitors may offer promising treatment for patients suffering from diabetes. The inhibitors act by increasing the loss of glucose in urine by decreasing the reabsorption of glucose from the proximal tubules of nephrons. The aim of this review was to assess the efficacy of sodium glucose co-transport inhibitors in the treatment of diabetes as well as any adverse effects. Databases such as MEDLINE, COCHRANE and EMBASE were systematically searched for literature on the efficacy of sodium glucose co-transport inhibitors in improving the glycemic control of patients with diabetes. Research showed that sodium glucose co-transport inhibitors significantly decreased blood glucose levels by increasing glucosuria. Due to the diuretic effects of these inhibitors, diabetic patients who were suffering from hypertension showed a decrease in blood pressure. The caloric loss associated with these inhibitors resulted in weight loss as well. The most common adverse effect seen in patients on these medications was mycotic infection of the urinary or genital tract. Sodium glucose co-transport inhibitors may be an effective line of treatment for diabetes. Although short-term research has shown these drugs to be safe and well-tolerated, studies should be conducted to assess the long-term effects of these drugs.

  3. Cotransport of water by Na¿-K¿-2Cl¿ cotransporters expressed in Xenopus oocytes

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Macaulay, Nanna

    2012-01-01

    . The osmotic effects of NaCl were smaller than those of urea and mannitol. This supports the notion of interaction between ions and water in NKCC1 and allows for an estimate of around 600 water molecules transported per turnover of the protein. Osmotic gradients did not induce water transport in NKCC2. We...... increases in external K¿ concentration elicited abrupt inward water fluxes in NKCC1; the K¿ dependence obeyed one-site kinetics with a K0.5 of 7.5 mM. The water fluxes were blocked by bumetanide, had steep temperature dependence and could proceed uphill against an osmotic gradient of 20 mosmol l......¿¹. A comparison between ion and water fluxes indicates that 460 water molecules are cotransported for each turnover of the protein. In contrast, NKCC2 did not support water fluxes.Water transport in NKCC1 induced by increases in the external osmolarity had high activation energy and was blocked by bumetanide...

  4. Cotransport of bismerthiazol and montmorillonite colloids in saturated porous media.

    Science.gov (United States)

    Shen, Chongyang; Wang, Hong; Lazouskaya, Volha; Du, Yichun; Lu, Weilan; Wu, Junxue; Zhang, Hongyan; Huang, Yuanfang

    2015-01-01

    While bismerthiazol [N,N'-methylene-bis-(2-amino-5-mercapto-1,3,4-thiadiazole)] is one of the most widely used bactericides, the transport of bismerthiazol in subsurface environments is unclear to date. Moreover, natural colloids are ubiquitous in the subsurface environments. The cotransport of bismerthiazol and natural colloids has not been investigated. This study conducted laboratory column experiments to examine the transport of bismerthiazol in saturated sand porous media both in the absence and presence of montmorillonite colloids. Results show that a fraction of bismerthiazol was retained in sand and the retention was higher at pH7 than at pH 4 and 10. The retention did not change with ionic strength. The retention was attributed to the complex of bismerthiazol with metals/metal oxides on sand surfaces through ligand exchange. The transport of bismerthiazol was enhanced with montmorillonite colloids copresent in the solutions and, concurrently, the transport of montmorillonite colloids was facilitated by the bismerthiazol. The transport of montmorillonite colloids was enhanced likely because the bismerthiazol and the colloids competed for the attachment/adsorption sites on collector surfaces and the presence of bismerthiazol changed the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies between colloids and collectors. The transport of bismerthiazol was inhibited if montmorillonite colloids were pre-deposited in sand because bismerthiazol could adsorb onto the colloid surfaces. The adsorbed bismerthiazol could be co-remobilized with the colloids from primary minima by decreasing ionic strength. Whereas colloid-facilitated transport of pesticides has been emphasized, our study implies that transport of colloids could also be facilitated by the presence of pesticides. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Absence of Na +/sugar cotransport activity in Barrett's metaplasia

    Institute of Scientific and Technical Information of China (English)

    Lisa J Murray; Owen Tully; David S Rudolph; Marysue Whitby; Mary C Valenzano; Giancarlo Mercogliano; James J Thornton; James M Mullin

    2008-01-01

    AIM:To evaluate the presence of Na+-dependent,active,sugar transport in Barrett's epithelia as an intestinal biomarker,based on the well-documented,morphological intestinal phenotype of Barrett's esophagus (BE).METHODS:We examined uptake of the nonmeta-bolizable glucose analogue,alpha-methyl-D-glucoside (AMG),a substrate for the entire sodium glucose cotransporter (SGLT) family of transport proteins.During upper endoscopy,patients with BE or with uncomplicated gastroesophageal reflux disease (GERD)allowed for duodenal,gastric fundic,and esophageal mucosal biopsies to be taken.Biopsies were incubated in bicarbonate-buffered saline (KRB) containing 0.1 mmol/L 14C-AMG for 60 min at 20℃.Characterized by abundant SGLT,duodenum served as a positive control while gastric fundus and normal esophagus,known to lack SGLT,sewed as negative controls.RESULTS:Duodenal biopsies accumulated 249.84± 35.49 (SEM) picomoles AMG/μg DNA (n = 12),gastric fundus biopsies 36.20 ± 6.62 (n = 12),normal esophagus 12.10 ± 0.59 (n = 3) and Barrett's metaplasia 29.79 ± 5.77 (n = 8).There was a statistical difference (P<0.01) between biopsies from duodenum and each other biopsy site but there was no statistically significant difference between normal esophagus and BE biopsies.0.5 mmol/L phlorizin (PZ) inhibited AMG uptake into duodenal mucosa by over 89%,but had no significant effect on AMG uptake into gastric fundus,normal esophagus,or Barrett's tissue.In the absence of Na+ (all Na+ salts replaced by Li+ salts),AMG uptake in duodenum was decreased by over 90%,while uptake into gastric,esophageal or Barrett's tissue was statistically unaffected.CONCLUSION:Despite the intestinal enterocyte phenotype of BE,Na+-dependent,sugar transport activity is not present in bhese cells.

  6. Human NKCC2 cation–Cl– co-transporter complements lack of Vhc1 transporter in yeast vacuolar membranes.

    Science.gov (United States)

    Petrezselyova, Silvia; Dominguez, Angel; Herynkova, Pavla; Macias, Juan F; Sychrova, Hana

    2013-10-01

    Cation–chloride co-transporters serve to transport Cl– and alkali metal cations. Whereas a large family of these exists in higher eukaryotes, yeasts only possess one cation–chloride co-transporter, Vhc1, localized to the vacuolar membrane. In this study, the human cation–chloride co-transporter NKCC2 complemented the phenotype of VHC1 deletion in Saccharomyces cerevisiae and its activity controlled the growth of salt-sensitive yeast cells in the presence of high KCl, NaCl and LiCl. A S. cerevisiae mutant lacking plasma-membrane alkali–metal cation exporters Nha1 and Ena1-5 and the vacuolar cation–chloride co-transporter Vhc1 is highly sensitive to increased concentrations of alkali–metal cations, and it proved to be a suitable model for characterizing the substrate specificity and transport activity of human wild-type and mutated cation–chloride co-transporters.

  7. Prolactin increases hepatic Na+/taurocholate co-transport activity and messenger RNA post partum.

    Science.gov (United States)

    Ganguly, T C; Liu, Y; Hyde, J F; Hagenbuch, B; Meier, P J; Vore, M

    1994-01-01

    We have shown that Na+/taurocholate co-transport activity is decreased in pregnancy, but rebounds post partum relative to non-pregnant controls, and that activity can be increased by treatment with ovine prolactin [Ganguly, Hyde and Vore (1993) J. Pharmacol. Exp. Ther. 267, 82-87]. To determine the basis for these effects, Na+/taurocholate co-transport was determined in purified basolateral liver plasma-membrane (bLPM) vesicles and compared with steady-state mRNA levels encoding the Na+/taurocholate-co-transporting polypeptide (Ntcp) in non-pregnant controls, pregnant rats (19-20 days pregnant), rats post partum (48 h post partum) and rats post partum treated with bromocriptine to inhibit prolactin secretion. Na+/taurocholate co-transport activity (nmol/5 s per mg of protein) in bLPM was decreased from 10.4 +/- 1.8 in non-pregnant controls to 7.9 +/- 0.6 in bLPM in pregnant rats, but rebounded to 17.5 +/- 1.3 post partum; treatment of rats post partum with bromocriptine to inhibit prolactin secretion decreased activity to 14.1 +/- 0.9. Northern and slot-blot analyses revealed similar changes in mRNA for Ntcp, so that a positive correlation was observed between Na+/taurocholate co-transport activity and Ntcp mRNA. Furthermore, treatment of ovariectomized rats with ovine prolactin increased Ntcp mRNA 10-fold compared with solvent-treated controls, consistent with the 2-fold increase in Vmax, for Na+/taurocholate co-transport in isolated hepatocytes. These data are the first to demonstrate endogenous physiological regulation by prolactin of Ntcp mRNA in parallel with Na+/taurocholate co-transport activity. Images Figure 2 PMID:7945260

  8. Exploring the intricate regulatory network controlling the thiazide-sensitive NaCl cotransporter (NCC).

    Science.gov (United States)

    Dimke, Henrik

    2011-12-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays key roles in renal electrolyte transport and blood pressure maintenance. Regulation of this cotransporter has received increased attention recently, prompted by the discovery that mutations in the with-no-lysine (WNK) kinases are the molecular explanation for pseudohypoaldosteronism type II (PHAII). Studies suggest that WNK4 regulates NCC via two distinct pathways, depending on its state of activation. Furthermore, an intact STE20-related proline-alanine-rich kinase (SPAK)/oxidative stress response 1 kinase (OSR1) pathway was found to be necessary for a WNK4 PHAII mutation to increase NCC phosphorylation and blood pressure in mice. The mouse protein 25α is a novel regulator of the SPAK/OSR1 kinase family, which greatly increases their activity. The phosphorylation status of NCC and the WNK is regulated by the serum- and glucocorticoid-inducible kinase 1, suggesting novel mechanisms whereby aldosterone modulates NCC activity. Dephosphorylation of NCC by protein phosphatase 4 strongly influences the activity of the cotransporter, confirming an important role for NCC phosphorylation. Finally, γ-adducin increases NCC activity. This stimulatory effect is dependent on the phosphorylation status of the cotransporter. γ-Adducin only binds the dephosphorylated cotransporter, suggesting that phosphorylation of NCC causes the dissociation of γ-adducin. Since γ-adducin is not a kinase, it is tempting to speculate that the protein exerts its function by acting as a scaffold between the dephosphorylated cotransporter and the regulatory kinase. As more molecular regulators of NCC are identified, the system-controlling NCC activity is becoming increasingly complex. This intricacy confers an ability to integrate a variety of stimuli, thereby regulating NCC transport activity and ultimately blood pressure.

  9. SODIUM-POTASSIUM-CHLORIDE COTRANSPORT IN THE REGULATION OF VASCULAR MYOGENIC TONE

    Directory of Open Access Journals (Sweden)

    S. N. Orlov

    2014-01-01

    Full Text Available The article discusses the data on the functioning of Na+,K+,2Cl– cotransport – the carrier providing electroneutral symport of sodium, potassium and chloride, as well as molecular mechanisms of the regulation and physiological significance of this carrier. We analyzed the novel data on involvement of ubiquitous isoform of Na+,K+,2Cl–cotransporter (NKCC1 in regulation of vascular smooth muscle contraction, and role of this carrier in the regulation of cell volume and intracellular chloride concentration.

  10. Mini-review: regulation of the renal NaCl cotransporter by hormones.

    Science.gov (United States)

    Rojas-Vega, Lorena; Gamba, Gerardo

    2016-01-01

    The renal thiazide-sensitive NaCl cotransporter, NCC, is the major pathway for salt reabsorption in the distal convoluted tubule. The activity of this cotransporter is critical for regulation of several physiological variables such as blood pressure, serum potassium, acid base metabolism, and urinary calcium excretion. Therefore, it is not surprising that numerous hormone-signaling pathways regulate NCC activity to maintain homeostasis. In this review, we will provide an overview of the most recent evidence on NCC modulation by aldosterone, angiotensin II, vasopressin, glucocorticoids, insulin, norepinephrine, estradiol, progesterone, prolactin, and parathyroid hormone.

  11. Conformational Dynamics of hSGLT1 during Na+/Glucose Cotransport

    DEFF Research Database (Denmark)

    Loo, D. D.; Hirayama, B. A.; Karakossian, M. H.

    2006-01-01

    . voltage (Q-V) and fluorescence vs. voltage ( F-V) relations (for medium and slow components) obeyed Boltzmann relations with similar parameters: z (apparent valence of voltage sensor) 1; and V0.5 (midpoint voltage) between -15 and -40 mV. Sugar induced an inward current (Na+/glucose cotransport......This study examines the conformations of the Na+/glucose cotransporter (SGLT1) during sugar transport using charge and fluorescence measurements on the human SGLT1 mutant G507C expressed in Xenopus oocytes. The mutant exhibited similar steady-state and presteady-state kinetics as wild-type SGLT1...

  12. Vasopressin induces phosphorylation of the thiazide-sensitive sodium chloride cotransporter in the distal convoluted tubule

    DEFF Research Database (Denmark)

    Pedersen, Nis Borbye; Hofmeister, Marlene Vind; Rosenbaek, Lena L;

    2010-01-01

    The thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) is important for renal electrolyte balance and its phosphorylation causes an increase in its transport activity and cellular localization. Here, we generated phospho-specific antibodies against two conserved N-terminal phosphorylation sites...

  13. The human Na+-glucose cotransporter is a molecular water pump

    DEFF Research Database (Denmark)

    Meinild, A; Klaerke, D A; Loo, D D

    1998-01-01

    1. The human Na+-glucose cotransporter (hSGLT1) was expressed in Xenopus laevis oocytes. The transport activity, given by the Na+ current, was monitored as a clamp current and the concomitant flux of water followed optically as the change in oocyte volume. 2. When glucose was added to the bathing...

  14. Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Loo, D D;

    2001-01-01

    water transport was divided about equally between cotransport, osmosis across the SGLT1 and osmosis across the native oocyte membrane. 6. Coexpression of AQP1 with the SGLT1 increased the water permeability more than 10-fold and steady state isotonic transport was achieved after less than 2 s of sugar...

  15. RasGRP1 stimulation enhances ubiquitination and endocytosis of the sodium-chloride cotransporter.

    NARCIS (Netherlands)

    Ko, B.; Kamsteeg, E.J.; Cooke, L.L.; Moddes, L.N.; Deen, P.M.T.; Hoover, R.S.

    2010-01-01

    The sodium-chloride cotransporter (NCC) is the principal salt-absorptive pathway in the distal convoluted tubule. Recently, we described a novel pathway of NCC regulation in which phorbol esters (PE) stimulate Ras guanyl-releasing protein 1 (RasGRP1), triggering a cascade ultimately activating ERK1/

  16. Na+/D-glucose cotransporter based bilayer lipid membrane sensor for D-glucose.

    Science.gov (United States)

    Sugao, N; Sugawara, M; Minami, H; Uto, M; Umezawa, Y

    1993-02-15

    A new type of amperometric blosensor for glucose was fabricated using a Na+/D-glucose cotransporter as the signal-transducing sensory element that exploits the D-glucose-triggered Na+ ion current through bilayer lipid membranes (BLMs). The planar BLM was formed by the folding method across a small aperture of a thin Teflon film. The Na+/D-glucose cotransporter, isolated and purified from small intestinal brush border membrane of guinea pigs, was embedded into BLMs through proteoliposomes. The number of the protein molecules thus incorporated in the present sensing membrane was estimated to be ca. 10(7). The sensor response was measured as an ionic current through the BLM arising from cotransported Na+ ion flux under a constant applied potential and was only induced by D-glucose above 10(-9) M, but not by the other monosaccharides except for D-galactose. The effect of applied potentials, Na+ and K+ ion concentrations, and the addition of a competitive inhibitor, phlorizin, were scrutinized to characterize the sensor output. The results were briefly discussed in terms of the potential use of the Na+/D-glucose cotransporter as a sensory element for D-glucose.

  17. Choroid plexus potassium cotransport: modulation by osmotic stress and external potassium.

    Science.gov (United States)

    Keep, R F; Xiang, J

    1995-06-01

    The choroid plexuses are involved in CSF secretion and CSF K homeostasis. This study examines the potential role of K cotransport in these two processes using isolated rat lateral ventricle choroid plexuses. Bumetanide-sensitive 86Rb influx and efflux were measured to assess the response of K cotransport to changes in media osmolality and K concentration. Alterations in osmolality had no effect on K uptake (in the presence or absence of bumetanide). However, the efflux rate constant for K was 0.29 +/- 0.02, 0.44 +/- 0.04, and 0.84 +/- 0.06 min-1 in 240, 300, and 424 mOsm/kg solutions, respectively (p brain shrinkage during hyperosmotic stress if the cotransporter is present on the apical membrane. The rate of bumetanide-sensitive efflux was unaffected by changes in external [K]. However, the rate of K uptake (measured on return to normal [K] media) was reduced gradually by exposure to low [K]. It was 21 +/- 1, 19 +/- 3, 13 +/- 2, and 6 +/- 1 nmol/mg/min after 0, 10, 30, and 60-min exposure to 1 mM K. Sixty minutes of exposure to 1 mM [K] abolished the bumetanide-sensitive K uptake present in plexuses exposed continually to normal media. This modulation of K cotransport by external [K] may be important in CSF K homeostasis by limiting K loss from the CSF if CSF [K] is low.

  18. RasGRP1 stimulation enhances ubiquitination and endocytosis of the sodium-chloride cotransporter.

    NARCIS (Netherlands)

    Ko, B.; Kamsteeg, E.J.; Cooke, L.L.; Moddes, L.N.; Deen, P.M.T.; Hoover, R.S.

    2010-01-01

    The sodium-chloride cotransporter (NCC) is the principal salt-absorptive pathway in the distal convoluted tubule. Recently, we described a novel pathway of NCC regulation in which phorbol esters (PE) stimulate Ras guanyl-releasing protein 1 (RasGRP1), triggering a cascade ultimately activating

  19. gamma-Adducin stimulates the thiazide-sensitive NaCl cotransporter

    NARCIS (Netherlands)

    Dimke, H.; San Cristobal, P.; Graaf, M.J. de; Lenders, J.W.M.; Deinum, J.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2011-01-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays a key role in renal salt reabsorption and the determination of systemic BP, but the molecular mechanisms governing the regulation of NCC are not completely understood. Here, through pull-down experiments coupled to mass spectrometry, we found

  20. Evidence for an apical Na-Cl cotransporter involved in ion uptake in a teleost fish

    Science.gov (United States)

    Hiroi, J.; Yasumasu, S.; McCormick, S.D.; Hwang, P.-P.; Kaneko, T.

    2008-01-01

    Cation-chloride cotransporters, such as the Na+/K +/2Cl- cotransporter (NKCC) and Na+/Cl - cotransporter (NCC), are localized to the apical or basolateral plasma membranes of epithelial cells and are involved in active ion absorption or secretion. The objectives of this study were to clone and identify 'freshwater-type' and 'seawater-type' cation-chloride cotransporters of euryhaline Mozambique tilapia (Oreochromis mossambicus) and to determine their intracellular localization patterns within mitochondria-rich cells (MRCs). From tilapia gills, we cloned four full-length cDNAs homologous to human cation-chloride cotransporters and designated them as tilapia NKCC1a, NKCC1b, NKCC2 and NCC. Out of the four candidates, the mRNA encoding NKCC1a was highly expressed in the yolk-sac membrane and gills (sites of the MRC localization) of seawater-acclimatized fish, whereas the mRNA encoding NCC was exclusively expressed in the yolk-sac membrane and gills of freshwater-acclimatized fish. We then generated antibodies specific for tilapia NKCC1a and NCC and conducted whole-mount immunofluorescence staining for NKCC1a and NCC, together with Na+/K+-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR) and Na+/H+ exchanger 3 (NHE3), on the yolk-sac membrane of tilapia embryos acclimatized to freshwater or seawater. The simultaneous quintuple-color immunofluorescence staining allowed us to classify MRCs clearly into four types: types I, II, III and IV. The NKCC1a immunoreactivity was localized to the basolateral membrane of seawater-specific type-IV MRCs, whereas the NCC immunoreactivity was restricted to the apical membrane of freshwater-specific type-II MRCs. Taking account of these data at the level of both mRNA and protein, we deduce that NKCC1a is the seawater-type cotransporter involved in ion secretion by type-IV MRCs and that NCC is the freshwater-type cotransporter involved in ion absorption by type-II MRCs. We propose a novel ion-uptake model by MRCs in

  1. Type II Na+-Pi cotransporters in osteoblast mineral formation: regulation by inorganic phosphate.

    Science.gov (United States)

    Lundquist, Patrik; Murer, Heini; Biber, Jürg

    2007-01-01

    During calcification of bone, large amounts of phosphate (P(i)) must be transported from the circulation to the osteoid. Likely candidates for osteoblast P(i) transport are the type II sodium-phosphate cotransporters NaPi-IIa and NaPi-IIb that facilitate transcellular P(i) flux in kidney and intestine, respectively. We have therefore determined the 'cotransporters' expression in osteoblast-like cells. We have also studied the 'cotransporters' regulation by P(i) and during mineralization in vitro. Phosphate uptake and cotransporter protein expression was investigated at early, late and mineralizing culture stages of mouse (MC3T3-E1) and rat (UMR-106) osteoblast-like cells. Both NaPi-IIa and NaPi-IIb were expressed by both osteoblast-like cell lines. NaPi-IIa was upregulated in both cell lines one week after confluency. After 7 days in 3mM P(i) NaPi-IIa was strongly upregulated in both cell lines. NaPi-IIb expression was unaffected by both culture stage and P(i) supplementation. The expression of both cotransporters was unaffected by P(i) deprivation. In vitro mineralization at 1.5mM P(i) was preceded by a three-fold increase in osteoblast sodium-dependent P(i) uptake and a corresponding upregulation of both NaPi-IIa and NaPi-IIb. Their expression thus seem regulated by phosphate in a manner consistent with their playing a role in transcellular P(i) flux during mineralization.

  2. Sodium Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus : Cardiovascular and Kidney Effects, Potential Mechanisms, and Clinical Applications

    NARCIS (Netherlands)

    Heerspink, Hiddo J. L.; Perkins, Bruce A.; Fitchett, David H.; Husain, Mansoor; Cherney, David Z. I.

    2016-01-01

    Sodium-glucose cotransporter-2 (SGLT2) inhibitors, including empagliflozin, dapagliflozin, and canagliflozin, are now widely approved antihyperglycemic therapies. Because of their unique glycosuric mechanism, SGLT2 inhibitors also reduce weight. Perhaps more important are the osmotic diuretic and

  3. Sodium Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus : Cardiovascular and Kidney Effects, Potential Mechanisms, and Clinical Applications

    NARCIS (Netherlands)

    Heerspink, Hiddo J. L.; Perkins, Bruce A.; Fitchett, David H.; Husain, Mansoor; Cherney, David Z. I.

    2016-01-01

    Sodium-glucose cotransporter-2 (SGLT2) inhibitors, including empagliflozin, dapagliflozin, and canagliflozin, are now widely approved antihyperglycemic therapies. Because of their unique glycosuric mechanism, SGLT2 inhibitors also reduce weight. Perhaps more important are the osmotic diuretic and na

  4. Flozins, inhibitors of type 2 renal sodium-glucose co-transporter – not only antihyperglycemic drugs

    OpenAIRE

    Mizerski Grzegorz; Kicinski Pawel; Jaroszynski Andrzej

    2015-01-01

    The kidneys play a crucial role in the regulation of the carbohydrate metabolism. In normal physiological conditions, the glucose that filters through the renal glomeruli is subsequently nearly totally reabsorbed in the proximal renal tubules. Two transporters are engaged in this process: sodium-glucose co-transporter type 1 (SGLT1), and sodium-glucose co-transporter type type 2 (SGLT2) - this being located in the luminal membrane of the renal tubular epithelial cells. It was found that the a...

  5. Cotransport of H+, lactate, and H2O in porcine retinal pigment epithelial cells

    DEFF Research Database (Denmark)

    Hamann, Steffen; Kiilgaard, Jens Folke; la Cour, Morten;

    2003-01-01

    and placed in a perfusion chamber in which the solution facing the retinal membrane could be changed rapidly. Two types of experiments were performed: Changes in cell water volume were measured by self-quenching of the fluorescent dye Calcein, and changes in intracellular pH were measured ratiometrically......) for the H(+) and lactate fluxes. The data suggest that H(2)O is cotransported along with H(+) and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue...... and supports our previous study performed by an invasive technique in an amphibian tissue....

  6. Sodium-glucose cotransporter 2 inhibitors with insulin in type 2 diabetes: Clinical perspectives

    OpenAIRE

    Mathew John; Deepa Gopinath; Rejitha Jagesh

    2016-01-01

    The treatment of type 2 diabetes is a challenging problem. Most subjects with type 2 diabetes have progression of beta cell failure necessitating the addition of multiple antidiabetic agents and eventually use of insulin. Intensification of insulin leads to weight gain and increased risk of hypoglycemia. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a class of antihyperglycemic agents which act by blocking the SGLT2 in the proximal tubule of the kidney. They have potential benefits in...

  7. OVER-EXPRESSION OF THE SODIUM CHLORIDE COTRANSPORTER IS NOT SUFFICIENT TO CAUSE FAMILIAL HYPERKALEMIC HYPERTENSION

    OpenAIRE

    McCormick, James A.; Nelson, Joshua H.; Yang, Chao-Ling; Curry, Joshua N.; Ellison, David H.

    2011-01-01

    The sodium chloride co-transporter (NCC) is the primary target of thiazides diuretics, drugs used commonly for long-term hypertension therapy. Thiazides also completely reverse the signs of Familial Hyperkalemic Hypertension (FHHt), suggesting that the primary defect in FHHt is increased NCC activity. To test whether increased NCC abundance alone is sufficient to generate the FHHt phenotype, we generated NCC transgenic mice; surprisingly, these mice did not display an FHHt-like phenotype. Sys...

  8. Enhanced expression of potassium-chloride cotransporter KCC2 in human temporal lobe epilepsy

    OpenAIRE

    Karlócai, MR; Wittner, L; Tóth, K; Maglóczky, Z.; Katarova, Z.; Rásonyi, G; Erőss, L; Czirják, S; Halász, P; G. Szabó; Payne, JA; Kaila, K.; Freund, TF

    2015-01-01

    © 2015 Springer-Verlag Berlin Heidelberg Synaptic reorganization in the epileptic hippocampus involves altered excitatory and inhibitory transmission besides the rearrangement of dendritic spines, resulting in altered excitability, ion homeostasis, and cell swelling. The potassium-chloride cotransporter-2 (KCC2) is the main chloride extruder in neurons and hence will play a prominent role in determining the polarity of GABAA receptor-mediated chloride currents. In addition, KCC2 also interact...

  9. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium–Glucose Cotransporter 2 Inhibition

    OpenAIRE

    Peters, Anne L.; Buschur, Elizabeth O.; Buse, John B.; Cohan, Pejman; Diner, Jamie C.; Hirsch, Irl B.

    2015-01-01

    OBJECTIVE Sodium–glucose cotransporter 2 (SGLT-2) inhibitors are the most recently approved antihyperglycemic medications. We sought to describe their association with euglycemic diabetic ketoacidosis (euDKA) in hopes that it will enhance recognition of this potentially life-threatening complication. RESEARCH DESIGN AND METHODS Cases identified incidentally are described. RESULTS We identified 13 episodes of SGLT-2 inhibitor–associated euDKA or ketosis in nine individuals, seven with type 1 d...

  10. Modeling glial contributions to seizures and epileptogenesis: cation-chloride cotransporters in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Zeid M Rusan

    Full Text Available Flies carrying a kcc loss-of-function mutation are more seizure-susceptible than wild-type flies. The kcc gene is the highly conserved Drosophila melanogaster ortholog of K+/Cl- cotransporter genes thought to be expressed in all animal cell types. Here, we examined the spatial and temporal requirements for kcc loss-of-function to modify seizure-susceptibility in flies. Targeted RNA interference (RNAi of kcc in various sets of neurons was sufficient to induce severe seizure-sensitivity. Interestingly, kcc RNAi in glia was particularly effective in causing seizure-sensitivity. Knockdown of kcc in glia or neurons during development caused a reduction in seizure induction threshold, cell swelling, and brain volume increase in 24-48 hour old adult flies. Third instar larval peripheral nerves were enlarged when kcc RNAi was expressed in neurons or glia. Results suggest that a threshold of K+/Cl- cotransport dysfunction in the nervous system during development is an important determinant of seizure-susceptibility in Drosophila. The findings presented are the first attributing a causative role for glial cation-chloride cotransporters in seizures and epileptogenesis. The importance of elucidating glial cell contributions to seizure disorders and the utility of Drosophila models is discussed.

  11. Cotransport of water and solutes in plant membranes: The molecular basis, and physiological functions

    Directory of Open Access Journals (Sweden)

    Lars H. Wegner

    2017-03-01

    Full Text Available Current concepts of plant membrane transport are based on the assumption that water and solutes move across membranes via separate pathways. According to this view, coupling between the fluxes is more or less exclusively constituted via the osmotic force that solutes exert on water transport. This view is questioned here, and experimental evidence for a cotransport of water and solutes is reviewed. The overview starts with ion channels that provide pathways for both ion and water transport, as exemplified for maxi K+ channels from cytoplasmic droplets of Chara corallina. Aquaporins are usually considered to be selective for water (just allowing for slippage of some other small, neutral molecules. Recently, however, a “dual function” aquaporin has been characterized from Arabidopsis thaliana (AtPIP2.1 that translocates water and at the same time conducts cations, preferentially Na+. By analogy with mammalian physiology, other candidates for solute-water flux coupling are cation-chloride cotransporters of the CCC type, and transporters of sugars and amino acids. The last part is dedicated to possible physiological functions that could rely on solute-water cotransport. Among these are the generation of root pressure, refilling of embolized xylem vessels, fast turgor-driven movements of leaves, cell elongation (growth, osmoregulation and adjustment of buoyancy in marine algae. This review will hopefully initiate further research in the field.

  12. Chloride-cotransport blockade desynchronizes neuronal discharge in the "epileptic" hippocampal slice.

    Science.gov (United States)

    Hochman, D W; Schwartzkroin, P A

    2000-01-01

    Antagonism of the chloride-cotransport system in hippocampal slices has been shown to block spontaneous epileptiform (i.e., hypersynchronized) discharges without diminishing excitatory synaptic transmission. Here we test the hypotheses that chloride-cotransport blockade, with furosemide or low-chloride (low-[Cl(-)](o)) medium, desynchronizes the firing activity of neuronal populations and that this desynchronization is mediated through nonsynaptic mechanisms. Spontaneous epileptiform discharges were recorded from the CA1 and CA3 cell body layers of hippocampal slices. Treatment with low-[Cl(-)](o) medium led to cessation of spontaneous synchronized bursting in CA1 >/=5-10 min before its disappearance from CA3. During the time that CA3 continued to burst spontaneously but CA1 was silent, electrical stimulation of the Schaffer collaterals showed that hyperexcited CA1 synaptic responses were maintained. Paired intracellular recordings from CA1 pyramidal cells showed that during low-[Cl(-)](o) treatment, the timing of action potential discharges became desynchronized; desynchronization was identified with phase lags in firing times of action potentials between pairs of neurons as well as a with a broadening and diminution of the CA1 field amplitude. Continued exposure to low-[Cl(-)](o) medium increased the degree of the firing-time phase shifts between pairs of CA1 pyramidal cells until the epileptiform CA1 field potential was abolished completely. Intracellular recordings during 4-aminopyridine (4-AP) treatment showed that prolonged low-[Cl(-)](o) exposure did not diminish the frequency or amplitude of spontaneous postsynaptic potentials. CA3 antidromic responses to Schaffer collateral stimulation were not significantly affected by prolonged low-[Cl(-)](o) exposure. In contrast to CA1, paired intracellular recordings from CA3 pyramidal cells showed that chloride-cotransport blockade did not cause a significant desynchronization of action potential firing times in the

  13. Modeling the co-transport of viruses and colloids in unsaturated porous media.

    Science.gov (United States)

    Seetha, N; Mohan Kumar, M S; Majid Hassanizadeh, S

    2015-10-01

    A mathematical model is developed to simulate the co-transport of viruses and colloids in unsaturated porous media under steady-state flow conditions. The virus attachment to the mobile and immobile colloids is described using a linear reversible kinetic model. Colloid transport is assumed to be decoupled from virus transport; that is, we assume that colloids are not affected by the presence of attached viruses on their surface. The governing equations are solved numerically using an alternating three-step operator splitting approach. The model is verified by fitting three sets of experimental data published in the literature: (1) Syngouna and Chrysikopoulos (2013) and (2) Walshe et al. (2010), both on the co-transport of viruses and clay colloids under saturated conditions, and (3) Syngouna and Chrysikopoulos (2015) for the co-transport of viruses and clay colloids under unsaturated conditions. We found a good agreement between observed and fitted breakthrough curves (BTCs) under both saturated and unsaturated conditions. Then, the developed model was used to simulate the co-transport of viruses and colloids in porous media under unsaturated conditions, with the aim of understanding the relative importance of various processes on the co-transport of viruses and colloids in unsaturated porous media. The virus retention in porous media in the presence of colloids is greater during unsaturated conditions as compared to the saturated conditions due to: (1) virus attachment to the air-water interface (AWI), and (2) co-deposition of colloids with attached viruses on its surface to the AWI. A sensitivity analysis of the model to various parameters showed that the virus attachment to AWI is the most sensitive parameter affecting the BTCs of both free viruses and total mobile viruses and has a significant effect on all parts of the BTC. The free and the total mobile viruses BTCs are mainly influenced by parameters describing virus attachment to the AWI, virus interaction

  14. Expression of the sodium potassium chloride cotransporter (NKCC1) and sodium chloride cotransporter (NCC) and their effects on rat lens transparency.

    Science.gov (United States)

    Chee, K N; Vorontsova, I; Lim, J C; Kistler, J; Donaldson, P J

    2010-05-04

    To characterize the expression patterns of the Na+-K+-Cl(-) cotransporter (NKCC) 1 and NKCC2, and the Na+-Cl(-) cotransporter (NCC) in the rat lens and to determine if they play a role in regulating lens volume and transparency. RT-PCR was performed on RNA extracted from fiber cells to identify sodium dependent cotransporters expressed in the rat lens. Western blotting and immunohistochemistry, using NKCC1, NKCC2, and NCC antibodies, were used to verify expression at the protein level and to localize transporter expression. Organ cultured rat lenses were incubated in Artificial Aqueous Humor (AAH) of varying osmolarities or isotonic AAH that contained either the NKCC specific inhibitor bumetanide, or the NCC specific inhibitor thiazide for up to 18 h. Lens transparency was monitored with dark field microscopy, while tissue morphology and antibody labeling patterns were recorded using a confocal microscope. Molecular experiments showed that NKCC1 and NCC were expressed in the lens at both the transcript and protein levels, but NKCC2 was not. Immunohistochemistry showed that both NKCC1 and NCC were expressed in the lens cortex, but NCC expression was also found in the lens core. In the lens cortex the majority of labeling for both transporters was cytoplasmic in nature, while in the lens core, NCC labeling was associated with the membrane. Exposure of lenses to either hypotonic or hypertonic AAH had no noticeable effects on the predominantly cytoplasmic location of either transporter in the lens cortex. Incubation of lenses in isotonic AAH plus the NKCC inhibitor bumetanide for 18 h induced a cortical opacity that was initiated by a shrinkage of peripheral fiber cells and the dilation of the extracellular space between fiber cells in a deeper zone located some approximately 150 microm in from the capsule. In contrast, lenses incubated in isotonic AAH and the NCC inhibitor thiazide maintained both their transparency and their regular fiber cell morphology. We have

  15. N-Glycosylation of the Na+-Taurocholate Cotransporting Polypeptide (NTCP) Determines Its Trafficking and Stability and Is Required for Hepatitis B Virus Infection

    Science.gov (United States)

    Appelman, Monique D.; Chakraborty, Anindita; Protzer, Ulrike; McKeating, Jane A.

    2017-01-01

    The sodium/bile acid cotransporter NTCP was recently identified as a receptor for hepatitis B virus (HBV). NTCP is glycosylated and the role of glycans in protein trafficking or viral receptor activity is not known. NTCP contains two N-linked glycosylation sites and asparagine amino acid residues N5 and N11 were mutated to a glutamine to generate NTCP with a single glycan (NTCP-N5Q or NTCP- N11Q) or no glycans (NTCP- N5,11Q). HepG2 cells expressing NTCP with a single glycan supported HBV infection at a comparable level to NTCP-WT. The physiological function of NTCP, the uptake of bile acids, was also not affected in cells expressing these single glycosylation variants, consistent with their trafficking to the plasma membrane. However, glycosylation-deficient NTCP (NTCP-N5,11Q) failed to support HBV infection, showed minimal cellular expression and was degraded in the lysosome. This affected the physiological bile acid transporter function of NTCP-N5,11Q in a similar fashion. In conclusion, N-glycosylation is required for efficient NTCP localization at the plasma membrane and subsequent HBV infection and these characteristics are preserved in NTCP carrying a single carbohydrate moiety. PMID:28125599

  16. A quantitative description of the Na-K-2Cl cotransporter and its conformity to experimental data.

    Science.gov (United States)

    Benjamin, B A; Johnson, E A

    1997-09-01

    In epithelia, the Na-K-2Cl cotransporter cooperates with other transport mechanisms to produce transepithelial NaCl transport. The reaction cycle for the Na-K-2Cl cotransporter has been established experimentally, but whether it accounts, quantitatively, for experimental findings has yet to be established. The differential equations that describe the reaction cycle were formulated, and the steady-state solutions were obtained by digital computation. Conformity between this description and the experimental data obtained from the literature was explored by automatic searches for the sets of rate constants that yielded statistical best-fits to the experimental data. Fits were obtained from renal epithelial cell lines, HeLa cells, and duck erythrocytes. Results show that the reaction cycle for the Na-K-2Cl cotransporter conforms well, quantitatively, with the experimental data.

  17. Effect of gravity on Pseudomonas putida and kaolinite cotransport in water saturated porous media

    Science.gov (United States)

    Vasiliadou, Ioanna A.; Chrysikopoulos, Constantinos V.

    2013-04-01

    Bacterial transport in porous media can be affected by several factors, such as cell concentration, water velocity, and attachment onto the solid matrix or suspended in the aqueous phase soil particles (e.g. clays). Gravity, also may significantly influence bacterial transport behavior in the subsurface. The present study aims to determine the gravity effect on transport and cotransport of bacteria species Pseudomonas (P.) putida and kaolinite colloid particles in porous media. Transport experiments were conducted under horizontal-, up- and down-flow conditions in water saturated columns packed with glass beads. These different flow modes represent different gravity effects, namely: no-, negative- and positive-gravity effect. Initial experiments were performed with bacteria and kaolinite alone in order to evaluate the effect of gravity on their individual transport characteristics. No significant gravity effect was observed on the transport of individual bacterial cells. In contrary, each different flow mode was found to differently affect kaolinite transport. Compared to the horizontal-flow mode, the kaolinite mass recovery was decreased during the up-flow mode, and increased during the down-flow mode. Finally, P. putida and kaolinite particles were injected simultaneously into the packed column in order to investigate their cotransport behavior under different flow modes. The experimental data indicated that the kaolinite-P. putida cotransport behavior was similar to that observed for the transport of individual kaolinite particles. It was observed that the P. putida mass recovery decreased during down-flow conditions. This phenomenon may be caused by the attachment of bacteria onto kaolinite particles, which were adsorbed onto the solid matrix.

  18. Substrate specificity of human ABCC4 (MRP4)-mediated cotransport of bile acids and reduced glutathione.

    Science.gov (United States)

    Rius, Maria; Hummel-Eisenbeiss, Johanna; Hofmann, Alan F; Keppler, Dietrich

    2006-04-01

    The multidrug resistance protein ABCC4 (MRP4), a member of the ATP-binding cassette superfamily, mediates ATP-dependent unidirectional efflux of organic anions out of cells. Previous studies showed that human ABCC4 is localized to the sinusoidal membrane of hepatocytes and mediates, among other substrates, the cotransport of reduced glutathione (GSH) with bile acids. In the present study, using inside-out membrane vesicles, we demonstrated that human ABCC4 in the presence of physiological concentrations of GSH has a high affinity for the taurine and glycine conjugates of the common natural bile acids as well as the unconjugated bile acid cholate. Chenodeoxycholyltaurine and chenodeoxycholylglycine were the GSH cosubstrates with the highest affinities for ABCC4, with K(m) values of 3.6 and 5.9 microM, respectively. Ursodeoxycholyltaurine and ursodeoxycholylglycine were cotransported together with GSH by ABCC4 with K(m) values of 7.8 and 12.5 microM, respectively, but no transport of ursodeoxycholate and deoxycholate was observed. The simultaneous transport of labeled GSH and cholyltaurine or cholylglycine was demonstrated in double-labeled cotransport experiments with a bile acid-to-GSH ratio of approximately 1:22. K(m) values of the bile acids for ABCC4 were in a range similar to those reported for the canalicular bile salt export pump ABCB11. Under physiological conditions, the sinusoidal ABCC4 may compete with canalicular ABCB11 for bile acids and thereby play a key role in determining the hepatocyte concentration of bile acids. In cholestatic conditions, ABCC4 may become a key pathway for efflux of bile acids from hepatocytes into blood.

  19. Na+/HCO3- Cotransport in Normal and Cystic Fibrosis Intestine

    Directory of Open Access Journals (Sweden)

    Seidler U

    2001-07-01

    Full Text Available In a search for the HCO(3(- supply mechanisms to the enterocyte we cloned and sequenced an intestinal subtype of the Na(+HCO(3(- cotransporter isoform I (dNBC1, which turned out to be identical to the pancreatic NBC1 subtype (pNBC1. Within the intestine, we found particularly high NBC1 expression levels in the duodenum and proximal colon. Experiments with stripped rabbit duodenum in Ussing-chambers revealed that Na(+HCO(3(- cotransport (NBC and CO(2 hydration/Na(+/H(+ exchange were equally important duodenal HCO(3(- supply pathways and were both upregulated during cAMP-mediated secretion. In the proximal colon, however, HCO(3(- secretion was low but NBC1 expression even higher than in the duodenum. Ussing-chamber experiments with an NBC-specific inhibitor revealed that NBC, coupled to basolateral Cl(-/HCO(3(- exchange, was an important alternative Cl(- supply pathway to Na(+K(+2Cl(- cotransport (NKCC during cAMP-stimulated colonic Cl(- secretion. To investigate the functional integrity of anion uptake pathways in the absence of cystic fibrosis transmembrane conductance regulator (CFTR, we fluorometrically assessed NBC and NKCC transport rates and cell volume before and during forskolin-stimulation in isolated colonic crypts from normal and CFTR (-/- mice. Although forskolin stimulation decreased cell volume only in normal, not in CFTR (-/- crypts, it activated NBC and NKCC to a similar degree in both normal and CFTR (-/- crypts. We conclude that, depending on the intestinal segment, NBC1 plays an important role in basolateral HCO(3(- or Cl(- uptake. Expression and activation by cAMP is preserved in CFTR (-/- intestine.

  20. DAPAGLIFLOZIN: SELECTIVE SODIUM-GLUCOSE CO-TRANSPORTER-2 INHIBITOR IN TYPE 2 DIABETES

    Directory of Open Access Journals (Sweden)

    Sudhakar Pemminati

    2011-11-01

    Full Text Available Dapagliflozin is a promising new drug that targets the so far untapped renal glucose reabsorption. By inhibiting sodium-glucose co-transporter-2 (SGLT2 which is mainly localized in the S1 segment of the proximal tubule, Dapagliflozin promotes renal glucose excretion and reduces hyperglycemia in an insulin-independent manner. Dapagliflozin also produces pronounced weight loss which may be an advantage in patients on sulfonylureas and insulin. Dapagliflozin has the potential to be used as monotherapy, as well as in combination with all approved antidiabetic agents.

  1. Sodium-glucose cotransporter-2 inhibition and the insulin: Glucagon ratio: Unexplored dimensions

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2015-01-01

    Full Text Available The sodium-glucose cotransporter 2 (SGLT-2 inhibitors are a novel class of glucose-lowering drugs which act by inhibiting the reabsorption of filtered glucose from the kidneys. Their effect on insulin and glucagon levels has recently been studied but is not fully explained. This communication proposes various hypotheses: A direct effect of SGLT-2 inhibition on the alpha cell receptors, a paracrine or intra-islet mediated effect on alpha cell sensitivity to glucose, and a calorie restriction mimetic action, to explain the impact of these drugs on the insulin glucagon ratio.

  2. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

    Science.gov (United States)

    Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A. G.

    2016-01-01

    This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a “good person,” who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production. PMID:27730088

  3. Water transport by the Na+/glucose cotransporter under isotonic conditions

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Klaerke, D A

    1997-01-01

    in Xenopus oocytes. We present a method which allows short-term exposures to sugar under voltage clamp conditions. We demonstrate that water is cotransported with the solutes despite no osmotic differences between the external and intracellular solutions. There is a fixed ratio of 195:1 between the number...... of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin....

  4. Regulation of the type Mb sodium-dependent phosphate cotransporter expression in the intestine

    Institute of Scientific and Technical Information of China (English)

    Bin WANG; Yulong YIN

    2009-01-01

    Phosphate (Pi) plays important roles in growth, development, bone mineralization, energy metabolism, nucleic acid synthesis, cell signaling, and acid-base regulation. The rate of intestinal absorption of Pi is a major determinant of Pi homeostasis. The type lib sodium- dependent Pi cotransporter (NaPi-Iib) is responsible for intestinal Pi absorption. Many physiological factors regulate the rate of Pi absorption via modulating the expression of NaPi-Iib in the intestine. In this review, we summarize the role of these factors in the regulation of NaPi-Iib expression in the intestine.

  5. Sodium-glucose co-transporter-2 inhibitors and euglycemic ketoacidosis: Wisdom of hindsight

    OpenAIRE

    Awadhesh Kumar Singh

    2015-01-01

    Sodium-glucose co-transporter-2 inhibitors (SGLT-2i) are newly approved class of oral anti-diabetic drugs, in the treatment of type 2 diabetes, which reduces blood glucose through glucouresis via the kidney, independent, and irrespective of available pancreatic beta-cells. Studies conducted across their clinical development program found, a modest reduction in glycated hemoglobin ranging from −0.5 to −0.8%, without any significant hypoglycemia. Moreover, head-to-head studies versus active com...

  6. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect.

    Science.gov (United States)

    Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A G

    2016-01-01

    This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

  7. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2 inhibition: Calorie restriction mimicry (CRM and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

  8. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC

    DEFF Research Database (Denmark)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B

    2012-01-01

    DAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin-angiotensin-aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1......The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho...

  9. Sodium-glucose cotransporter 2 inhibitor use: A pharmaco-ergonomic qualification tool

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2017-01-01

    Full Text Available Pharmaco-ergonomics implies tailoring the drug therapy to an individual patient's requirement(s. The development of sodium-glucose cotransporter 2 inhibitor (SGLT2-i agents has impelled multiple clinical considerations, in the management of type-2 diabetes. This paper attempts to summarize the pharmaco-ergonomic considerations for these agents, in the form of an SGLT2-i qualification tool, based on a clinical score. This tool may serve as a simple and inexpensive practical guide, to optimize the risk-benefit considerations for SGLT2-i agents.

  10. Angiotensin II directly stimulates macula densa Na-2Cl-K cotransport via apical AT(1) receptors.

    Science.gov (United States)

    Kovács, Gergely; Peti-Peterdi, János; Rosivall, László; Bell, P Darwin

    2002-02-01

    ANG II is a modulator of tubuloglomerular feedback (TGF); however, the site of its action remains unknown. Macula densa (MD) cells sense changes in luminal NaCl concentration ([NaCl](L)) via a Na-2Cl-K cotransporter, and these cells do possess ANG II receptors. We tested whether ANG II regulates Na-2Cl-K cotransport in MD cells. MD cell Na(+) concentration ([Na(+)](i)) was measured using sodium-binding benzofuran isophthalate with fluorescence microscopy. Resting [Na(+)](i) in MD cells was 27.7 +/- 1.05 mM (n = 138) and increased (Delta[Na(+)](i)) by 18.5 +/- 1.14 mM (n = 17) at an initial rate (Delta[Na(+)](i)/Deltat) of 5.54 +/- 0.53 x 10(-4) U/s with an increase in [NaCl](L) from 25 to 150 mM. Both Delta[Na(+)](i) and Delta[Na(+)](i)/Deltat were inhibited by 80% with 100 microM luminal furosemide. ANG II (10(-9) or 10(-12) M) added to the lumen increased MD resting [Na(+)](i) and [NaCl](L)-dependent Delta[Na(+)](i) and caused a twofold increase in Delta[Na(+)](i)/Deltat. Bath (10(-9) M) ANG II also stimulated cotransport activity, and there was no additive effect of simultaneous addition of ANG II to bath and lumen. The effects of luminal ANG II were furosemide sensitive and abolished by the AT(1) receptor blocker candesartan. ANG II at 10(-6) M failed to stimulate the cotransporter, whereas increased cotransport activity could be restored by blocking AT(2) receptors with PD-123, 319. Thus ANG II may modulate TGF responses via alterations in MD Na-2Cl-K cotransport activity.

  11. Molecular characterization of a putative K-Cl cotransporter in rat brain. A neuronal-specific isoform.

    Science.gov (United States)

    Payne, J A; Stevenson, T J; Donaldson, L F

    1996-07-05

    Using a combination of data base searching, polymerase chain reaction, and library screening, we have identified a putative K-Cl cotransporter isoform (KCC2) in rat brain that is specifically localized in neurons. A cDNA of 5566 bases was obtained from overlapping clones and encoded a protein of 1116 amino acids with a deduced molecular mass of 123.6 kDa. Over its full length, the amino acid sequence of KCC2 is 67% identical to the widely distributed K-Cl cotransporter isoform (KCC1) identified in rat brain and rabbit kidney (Gillen, C., Brill, S., Payne, J.A., and Forbush, B., III(1996) J. Biol. Chem. 271, 16237-16244) but only approximately25% identical to other members of the cation-chloride cotransporter gene family, including "loop" diuretic-sensitive Na-K-Cl cotransport and thiazide-sensitive Na-Cl cotransport. Based on analysis of the primary structure as well as homology with other cation-chloride cotransporters, we predict 12 transmembrane segments bounded by N- and C-terminal cytoplasmic regions. Four sites for N-linked glycosylation are predicted on an extracellular intermembrane loop between putative transmembrane segments 5 and 6. Northern blot analysis using a KCC2-specific cDNA probe revealed a very highly expressed approximately5.6-kilobase transcript only in brain. Reverse transcriptase-polymerase chain reaction revealed that KCC1 was present in rat primary astrocytes and rat C6 glioma cells but that KCC2 was completely absent from these cells, suggesting KCC2 was not of glial cell origin. In situ hybridization studies demonstrated that the KCC2 transcript was expressed at high levels in neurons throughout the central nervous system, including CA1-CA4 pyramidal neurons of the hippocampus, granular cells and Purkinje neurons of the cerebellum, and many groups of neurons throughout the brainstem.

  12. Histone Variants and Epigenetics

    Science.gov (United States)

    Henikoff, Steven; Smith, M. Mitchell

    2015-01-01

    Histones package and compact DNA by assembling into nucleosome core particles. Most histones are synthesized at S phase for rapid deposition behind replication forks. In addition, the replacement of histones deposited during S phase by variants that can be deposited independently of replication provide the most fundamental level of chromatin differentiation. Alternative mechanisms for depositing different variants can potentially establish and maintain epigenetic states. Variants have also evolved crucial roles in chromosome segregation, transcriptional regulation, DNA repair, and other processes. Investigations into the evolution, structure, and metabolism of histone variants provide a foundation for understanding the participation of chromatin in important cellular processes and in epigenetic memory. PMID:25561719

  13. Sites of regulated phosphorylation that control K-Cl cotransporter activity.

    Science.gov (United States)

    Rinehart, Jesse; Maksimova, Yelena D; Tanis, Jessica E; Stone, Kathryn L; Hodson, Caleb A; Zhang, Junhui; Risinger, Mary; Pan, Weijun; Wu, Dianqing; Colangelo, Christopher M; Forbush, Biff; Joiner, Clinton H; Gulcicek, Erol E; Gallagher, Patrick G; Lifton, Richard P

    2009-08-07

    Modulation of intracellular chloride concentration ([Cl(-)](i)) plays a fundamental role in cell volume regulation and neuronal response to GABA. Cl(-) exit via K-Cl cotransporters (KCCs) is a major determinant of [Cl(-)](I); however, mechanisms governing KCC activities are poorly understood. We identified two sites in KCC3 that are rapidly dephosphorylated in hypotonic conditions in cultured cells and human red blood cells in parallel with increased transport activity. Alanine substitutions at these sites result in constitutively active cotransport. These sites are highly phosphorylated in plasma membrane KCC3 in isotonic conditions, suggesting that dephosphorylation increases KCC3's intrinsic transport activity. Reduction of WNK1 expression via RNA interference reduces phosphorylation at these sites. Homologous sites are phosphorylated in all human KCCs. KCC2 is partially phosphorylated in neonatal mouse brain and dephosphorylated in parallel with KCC2 activation. These findings provide insight into regulation of [Cl(-)](i) and have implications for control of cell volume and neuronal function.

  14. Exon loss accounts for differential sorting of Na-K-Cl cotransporters in polarized epithelial cells.

    Science.gov (United States)

    Carmosino, Monica; Giménez, Ignacio; Caplan, Michael; Forbush, Biff

    2008-10-01

    The renal Na-K-Cl cotransporter (NKCC2) is selectively expressed in the apical membranes of cells of the mammalian kidney, where it is the target of the clinically important loop diuretics. In contrast, the "secretory" NKCC1 cotransporter is localized in the basolateral membranes of many epithelia. To identify the sorting signal(s) that direct trafficking of NKCCs, we generated chimeras between the two isoforms and expressed these constructs in polarized renal epithelial cell lines. This analysis revealed an amino acid stretch in NKCC2 containing apical sorting information. The NKCC1 C terminus contains a dileucine motif that constitutes the smallest essential component of its basolateral sorting signal. NKCC1 lacking this motif behaves as an apical protein. Examination of the NKCC gene structure reveals that this dileucine motif is encoded by an additional exon in NKCC1 absent in NKCC2. Phylogenetic analysis of this exon suggests that the evolutionary loss of this exon from the gene encoding the basolateral NKCC1 constitutes a novel mechanism that accounts for the apical sorting of the protein encoded by the NKCC2 gene.

  15. Potassium co-transport and antiport during the uptake of sucrose and glutamic acid from the xylem vessels

    NARCIS (Netherlands)

    Bel, A.J.E. van; Erven, A.J. van

    1979-01-01

    Perfusion experiments with excised internodes of tomato (Lycopersicon esculentum cv Moneymaker) showed that the uptake of glutamic acid and sucrose from the xylem vessels is accompanied with coupled proton co-transport and potassium antiport at low pH (<5.5). At high pH (5.5) both proton and potassi

  16. Potassium co-transport and antiport during the uptake of sucrose and glutamic acid from the xylem vessels

    NARCIS (Netherlands)

    Bel, A.J.E. van; Erven, A.J. van

    1979-01-01

    Perfusion experiments with excised internodes of tomato (Lycopersicon esculentum cv Moneymaker) showed that the uptake of glutamic acid and sucrose from the xylem vessels is accompanied with coupled proton co-transport and potassium antiport at low pH (<5.5). At high pH (5.5) both proton and potassi

  17. Hydrochlorothiazide treatment increases the abundance of the NaCl cotransporter in urinary extracellular vesicles of essential hypertensive patients.

    NARCIS (Netherlands)

    Pathare, G.T.; Tutakhel, O.A.Z.; Wel, M.C. van der; Shelton, L.M.; Deinum, J.; Lenders, J.W.M.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2017-01-01

    The thiazide-sensitive NaCl cotransporter (NCC), located apically in distal convoluted tubule epithelia, regulates the fine-tuning of renal sodium excretion. Three isoforms of NCC are generated through alternative splicing of the transcript, of which the third isoform has been the most extensively

  18. NaCl cotransporter abundance in urinary vesicles is increased by calcineurin inhibitors and predicts thiazide sensitivity

    NARCIS (Netherlands)

    Tutakhel, O.A.Z.; Moes, A.D.; Valdez Flores, M.A.; Kortenoeven, M.L.A.; Vrie, M. van de; Jelen, S.K.; Fenton, R.A.; Zietse, R.; Hoenderop, J.G.J.; Hoorn, E.J.; Hilbrands, L.B.; Bindels, R.J.M.

    2017-01-01

    Animal studies have shown that the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus can activate the thiazide-sensitive NaCl cotransporter (NCC). A common side effect of CNIs is hypertension. Renal salt transporters such as NCC are excreted in urinary extracellular vesicles (uEVs) after

  19. NaCl cotransporter abundance in urinary vesicles is increased by calcineurin inhibitors and predicts thiazide sensitivity

    NARCIS (Netherlands)

    Tutakhel, O.A.Z. (Omar A. Z.); A.D. Moes (Arthur); Valdez-Flores, M.A. (Marco A.); Kortenoeven, M.L.A. (Marleen L. A.); Vrie, M.V.D. (Mathijs V.D.); Jelen, S. (Sabina); R.A. Fenton (Robert); R. Zietse (Bob); J.G.J. Hoenderop (Joost); E.J. Hoorn (Ewout); L.B. Hilbrands (Luuk); Bindels, R.J.M. (Reneâ J. M.)

    2017-01-01

    textabstractAnimal studies have shown that the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus can activate the thiazide-sensitive NaCl cotransporter (NCC). A common side effect of CNIs is hypertension. Renal salt transporters such as NCC are excreted in urinary extracellular vesicles

  20. Diabetic Ketoacidosis in a Patient with Type 2 Diabetes After Initiation of Sodium-Glucose Cotransporter 2 Inhibitor Treatment

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Bagger, Jonatan I; Knop, Filip K

    2016-01-01

    Sodium-glucose cotransporter 2 inhibitors (SGLT2i) were recently introduced for the treatment of type 2 diabetes (T2D). SGLT2i lower plasma glucose by inhibiting the renal reuptake of glucose leading to glucosuria. Generally, these drugs are considered safe to use. However, recently, SGLT2i have...

  1. Contribution of Na+,HCO3--cotransport to cellular pH control in human breast cancer

    DEFF Research Database (Denmark)

    Bødtkjer, Ebbe; Moreira, José; Mele, Marco

    2013-01-01

    H-sensitive fluorophores, we showed that Na(+) ,HCO(3) (-) -cotransport is the predominant mechanism of acid extrusion and is inhibited 34 ± 9% by 200 µM 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid in human primary breast carcinomas. At intracellular pH (pH(i) ) levels >6.6, CO(2) /HCO(3) (-) -dependent mechanisms...

  2. Determination of the Na(+)/glucose cotransporter (SGLT1) turnover rate using the ion-trap technique.

    Science.gov (United States)

    Longpré, Jean-Philippe; Lapointe, Jean-Yves

    2011-01-05

    The Na(+)/glucose cotransporter (SGLT1) is a membrane protein that couples the transport of two Na(+) ions and one glucose molecule using the so-called alternating access mechanism. According to this principle, each cotransporter molecule can adopt either of two main conformations: one with the binding sites accessible to the extracellular solution and one with the binding sites facing the intracellular solution. The turnover rate (TOR) is the number of complete cycles that each protein performs per second. Determination of the TOR has important consequences for investigation of the cotransport mechanism, as none of the rate constants involved in mediating transport in a given direction (conformational changes and binding and unbinding reactions) can be slower than the TOR measured under the same conditions. In addition, the TOR can be used to estimate the number of cotransporter molecules involved in generating a given ensemble activity. In this study, we obtain an independent estimation of the TOR for human SGLT1 expressed in Xenopus laevis oocytes applying the ion-trap technique. This approach detects the quantity of ions released in or taken up from the restricted space existing between the oocyte plasma membrane and the tip of a large ion-selective electrode. Taking advantage of the fact that hSGLT1 in the absence of Na(+) can cotransport glucose with protons, we used a pH electrode to determine a TOR of 8.00 ± 1.3 s⁻¹ in the presence of 35 mM α-methyl-glucose at -150 mV (pH 5.5). For the same group of oocytes, a TOR of 13.3 ± 2.4 s⁻¹ was estimated under near-V(max) conditions, i.e., in the presence of 90 mM Na(+) and 5 mM α-methyl-glucose. Under these circumstances, the average cotransport current was -1.08 ± 0.61 μA (n = 14), and this activity was generated by an average of 3.6 ± 0.7 × 10¹¹ cotransporter molecules/oocyte. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Determination of the Na+/Glucose Cotransporter (SGLT1) Turnover Rate Using the Ion-Trap Technique

    Science.gov (United States)

    Longpré, Jean-Philippe; Lapointe, Jean-Yves

    2011-01-01

    The Na+/glucose cotransporter (SGLT1) is a membrane protein that couples the transport of two Na+ ions and one glucose molecule using the so-called alternating access mechanism. According to this principle, each cotransporter molecule can adopt either of two main conformations: one with the binding sites accessible to the extracellular solution and one with the binding sites facing the intracellular solution. The turnover rate (TOR) is the number of complete cycles that each protein performs per second. Determination of the TOR has important consequences for investigation of the cotransport mechanism, as none of the rate constants involved in mediating transport in a given direction (conformational changes and binding and unbinding reactions) can be slower than the TOR measured under the same conditions. In addition, the TOR can be used to estimate the number of cotransporter molecules involved in generating a given ensemble activity. In this study, we obtain an independent estimation of the TOR for human SGLT1 expressed in Xenopus laevis oocytes applying the ion-trap technique. This approach detects the quantity of ions released in or taken up from the restricted space existing between the oocyte plasma membrane and the tip of a large ion-selective electrode. Taking advantage of the fact that hSGLT1 in the absence of Na+ can cotransport glucose with protons, we used a pH electrode to determine a TOR of 8.00 ± 1.3 s−1 in the presence of 35 mM α-methyl-glucose at −150 mV (pH 5.5). For the same group of oocytes, a TOR of 13.3 ± 2.4 s−1 was estimated under near-Vmax conditions, i.e., in the presence of 90 mM Na+ and 5 mM α-methyl-glucose. Under these circumstances, the average cotransport current was −1.08 ± 0.61 μA (n = 14), and this activity was generated by an average of 3.6 ± 0.7 × 1011 cotransporter molecules/oocyte. PMID:21190656

  4. 盐碱胁迫对尼罗罗非鱼鳃Na+/3HCO共转运子、碳酸酐酶基因表达的影响%Effects of salinity and alkalinity on mRNA expression of Na+/3HCO cotransporter and carbonic anhydrase genes fromOreochromis niloticus

    Institute of Scientific and Technical Information of China (English)

    梁从飞; 赵金良; 甘远迪; 王飞; Thammaratsuntorn Jeerawat; 伍勇; 李传阳; 罗明坤

    2016-01-01

    To understand fish osmotic adjustment mechanisms in saline and alkaline water, the partial cDNA se-quence was obtained from gills ofOreochromis niloticus. Physiological changes in serum osmolality, ion concen-tration (Na+, K+, Cl– and Ca2+), and gill carbonic anhydrase (CA) activities were determined, andCAandNBCe1 mRNA gene expressions under saline (10 g/L, 15 g/L NaCl), alkaline (1.5 g/L and 3 g/L NaHCO3), and sa-line-alkaline (salinity 10, 15 g/L NaCl; salinity 1.5, 3 g/L NaHCO3) conditions at different times (0 h, 6 h, 12 h, 24 h, 48 h, 72 h and 96 h) were compared. The results showed that serum osmolality, ion concentration, gill CA activity, CA andNBCe1 mRNA gene expression correlated positively with the strength of saline, alkaline and sa-line-alkaline stress. Over time, serum osmolality and ion concentration trends increased and then decreased. Os-motic pressure insaline and saline-alkaline water was higher than that in alkaline water. Gill CA activity in alkaline and saline-alkaline water was higher than that in saline water. Under low concentrations of stressors, CA activity reached its highest level at a later time. Slightly higherNBCe1 gene mRNA expression was detected in gills under high concentrations of stressors (P>0.05). GillCA mRNA expression in saline, alkaline and saline-alkaline water was increased, but the increase was more evident in alkaline and saline-alkaline water (P0.05)。单碱组和盐碱混合组鳃CA活性较单盐组高,低盐碱胁迫(盐度10,碱度1.5 g/L)下CA活性较晚达最高值;不同胁迫条件下, CA基因mRNA表达均表现上调,单碱、盐碱混合组更为显著(P<0.05),推测CA较NBCe1对体内3HCO-转运作用更为显著。研究结果为尼罗罗非鱼盐碱适应生理调节提供了基础资料。

  5. Desmoplastic variant of ameloblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Jeong Ick; Kim, Dong Youn; Choi, Karp Shik [Dept. of Dental Radiology, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

    1995-02-15

    Desmoplastic variant of ameloblastoma is new and unusual variant of ameloblastoma with extensive stromal desmoplastic proliferation. The authors experienced a case of desmoplastic variant of amleloblastoma with moderate-defined radiolucency on the right maxillary anterior area in 62-year-old female. As a result of careful analysis of clinical, radiological examinations, we diagnosed it as desmoplastic variant of ameloblastoma. The following results were obtained; 1. Main clinical symptoms were nontender bony swelling with normal intact overlying mucosa on the right maxillary anterior area. 2. Radiographically, moderate-defined, multilocular radioluceney on the right maxillary anterior area were shown, and severe cortical bony thinning and expansion to labial and palatal sides were also observed. And this lesion was shown to be extended to the right nasal cavity. 3. Histopathologically, follicle-like epithelial islands with densely abundant collagenous stroma were morphologically compressed.

  6. Ipragliflozin: A novel sodium-glucose cotransporter 2inhibitor developed in Japan

    Institute of Scientific and Technical Information of China (English)

    Tsuyoshi Ohkura

    2015-01-01

    Sodium-glucose cotransporter 2 (SGLT2) inhibitioninduces glucosuria and decreases blood glucose levelsin diabetic patients and lowers hypoglycemic risk.SGLT1 is expressed in the kidney and intestine; SGLT1inhibition causes abdominal symptoms such as diarrheaand reduces incretin secretion. Therefore, SGLT2selectivity is important. Ipragliflozin is highly selectivefor SGLT2. In type 2 diabetes mellitus (T2DM), urinaryglucose excretion increased to 90 g/24 h after 28 d oftreatment with ipragliflozin 300 mg/d. Twelve weeksof ipragliflozin 50 mg/d vs placebo reduced glycatedhemoglobin and body weight by 0.65% and 0.66kg, respectively, in Western T2DM patients, and by1.3% and 1.89 kg, respectively, in Japanese patients.Ipragliflozin (highly selective SGLT2 inhibitor) improvesglycemic control and reduces body weight andlowers hypoglycemic risk and abdominal symptoms.Ipragliflozin can be a novel anti-diabetic and antiobesityagent.

  7. Extended life-span conferred by cotransporter gene mutations in Drosophila.

    Science.gov (United States)

    Rogina, B; Reenan, R A; Nilsen, S P; Helfand, S L

    2000-12-15

    Aging is genetically determined and environmentally modulated. In a study of longevity in the adult fruit fly, Drosophila melanogaster, we found that five independent P-element insertional mutations in a single gene resulted in a near doubling of the average adult life-span without a decline in fertility or physical activity. Sequence analysis revealed that the product of this gene, named Indy (for I'm not dead yet), is most closely related to a mammalian sodium dicarboxylate cotransporter-a membrane protein that transports Krebs cycle intermediates. Indy was most abundantly expressed in the fat body, midgut, and oenocytes: the principal sites of intermediary metabolism in the fly. Excision of the P element resulted in a reversion to normal life-span. These mutations may create a metabolic state that mimics caloric restriction, which has been shown to extend life-span.

  8. Sodium-glucose cotransporter 2 (SGLT-2) inhibitors for patients with Type 2 diabetes

    DEFF Research Database (Denmark)

    Røder, Michael Einar; Storgaard, Heidi; Rungby, Jørgen;

    2016-01-01

    problem. Extremely rare cases of ketoacidosis are reported, mostly in patients with Type 1 diabetes. One SGLT-2i, empagliflozin, has been shown to reduce cardiovascular mortality and progression of kidney disease in patients with Type 2 diabetes and cardiovascular disease. Outcome trials for other SGLT-2i......The sodium-glucose cotransporter 2 inhibitor (SGLT-2i)-class is efficacious as monotherapy and as add-on therapy with an expected lowering of the glycated haemoglobin (HbA1c) concentration of approximately 7 mmol/mol. Side effects relate to the mode of action, genital infections are the main...... are pending. SGLT-2i are now in guidelines as a possible second-line therapy or in case of metformin intolerance....

  9. γ-Adducin stimulates the thiazide-sensitive NaCl cotransporter

    DEFF Research Database (Denmark)

    Dimke, Henrik Anthony; San-Cristobal, Pedro; de Graaf, Mark

    2011-01-01

    The thiazide-sensitive NaCl cotransporter (NCC) plays a key role in renal salt reabsorption and the determination of systemic BP, but the molecular mechanisms governing the regulation of NCC are not completely understood. Here, through pull-down experiments coupled to mass spectrometry, we found...... that γ-adducin interacts with the NCC transporter. γ-Adducin colocalized with NCC to the distal convoluted tubule. (22)Na(+) uptake experiments in the Xenopus laevis oocyte showed that γ-adducin stimulated NCC activity in a dose-dependent manner, an effect that occurred upstream from With No Lysine (WNK......) 4 kinase. The binding site of γ-adducin mapped to the N terminus of NCC and encompassed three previously reported phosphorylation sites. Supporting this site of interaction, competition with the N-terminal domain of NCC abolished the stimulatory effect of γ-adducin on the transporter. γ...

  10. cAMP-dependent and cholinergic regulation of the electrogenic intestinal/pancreatic Na+/HCO3- cotransporter pNBC1 in human embryonic kidney (HEK293 cells

    Directory of Open Access Journals (Sweden)

    Soleimani Manoocher

    2008-12-01

    Full Text Available Abstract Background The renal (kNBC1 and intestinal (pNBC1 electrogenic Na+/HCO3- cotransporter variants differ in their primary structure, transport direction, and response to secretagogues. Previous studies have suggested that regulatory differences between the two subtypes can be partially explained by unique consensus phosphorylation sites included in the pNBC1, but not the kNBC1 sequence. After having shown activation of NBC by carbachol and forskolin in murine colon, we now investigated these pathways in HEK293 cells transiently expressing a GFP-tagged pNBC1 construct. Results Na+- and HCO3--dependent pHi recovery from an acid load (measured with BCECF was enhanced by 5-fold in GFP-positive cells compared to the control cells in the presence of CO2/HCO3-. Forskolin (10-5 M had no effect in untransfected cells, but inhibited the pHi recovery in cells expressing pNBC1 by 62%. After preincubation with carbachol (10-4 M, the pHi recovery was enhanced to the same degree both in transfected and untransfected cells, indicating activation of endogenous alkalizing ion transporters. Acid-activated Na+/HCO3- cotransport via pNBC1 expressed in renal cells is thus inhibited by cAMP and not affected by cholinergic stimulation, as opposed to the findings in native intestinal tissue. Conclusion Regulation of pNBC1 by secretagogues appears to be not solely dependent on its primary structure, but also on properties of the cell type in which it is expressed.

  11. Regulators of Slc4 bicarbonate transporter activity

    Directory of Open Access Journals (Sweden)

    Ian M. Thornell

    2015-06-01

    Full Text Available The Slc4 family of transporters is comprised of anion exchangers (AE1-4, Na-coupled bicarbonate transporters (NCBTs including electrogenic Na/bicarbonate cotransporters (NBCe1 and NBCe2, electroneutral Na/bicarbonate cotransporters (NBCn1 and NBCn2, and the electroneutral Na-driven Cl-bicarbonate exchanger (NDCBE, as well as a borate transporter (BTR1. These transporters regulate intracellular pH (pHi and contribute to steady-state pHi, but are also involved in other physiological processes including CO2 carriage by red blood cells and solute secretion/reabsorption across epithelia. Acid-base transporters function as either acid extruders or acid loaders, with the Slc4 proteins moving HCO3– either into or out of cells. According to results from both molecular and functional studies, multiple Slc4 proteins and/or associated splice variants with similar expected effects on pHi are often found in the same tissue or cell. Such apparent redundancy is likely to be physiologically important. In addition to regulating pHi, a HCO3– transporter contributes to a cell’s ability to fine tune the intracellular regulation of the cotransported/exchanged ion(s (e.g., Na+ or Cl–. In addition, functionally similar transporters or splice variants with different regulatory profiles will optimize pH physiology and solute transport under various conditions or within subcellular domains. Such optimization will depend on activated signaling pathways and transporter expression profiles. In this review, we will summarize and discuss both classical and more recently identified regulators of the Slc4 proteins. Some of these regulators include traditional second messengers, lipids, binding proteins, autoregulatory domains, and less conventional regulators. The material presented will provide insight into the diversity and physiological significance of multiple members within the Slc4 gene family.

  12. Calcineurin inhibitor cyclosporine A activates renal Na-K-Cl cotransporters via local and systemic mechanisms.

    Science.gov (United States)

    Blankenstein, K I; Borschewski, A; Labes, R; Paliege, A; Boldt, C; McCormick, J A; Ellison, D H; Bader, M; Bachmann, S; Mutig, K

    2017-03-01

    Calcineurin dephosphorylates nuclear factor of activated T cells transcription factors, thereby facilitating T cell-mediated immune responses. Calcineurin inhibitors are instrumental for immunosuppression after organ transplantation but may cause side effects, including hypertension and electrolyte disorders. Kidneys were recently shown to display activation of the furosemide-sensitive Na-K-2Cl cotransporter (NKCC2) of the thick ascending limb and the thiazide-sensitive Na-Cl cotransporter (NCC) of the distal convoluted tubule upon calcineurin inhibition using cyclosporin A (CsA). An involvement of major hormones like angiotensin II or arginine vasopressin (AVP) has been proposed. To resolve this issue, the effects of CsA treatment in normal Wistar rats, AVP-deficient Brattleboro rats, and cultured renal epithelial cells endogenously expressing either NKCC2 or NCC were studied. Acute administration of CsA to Wistar rats rapidly augmented phosphorylation levels of NKCC2, NCC, and their activating kinases suggesting intraepithelial activating effects. Chronic CsA administration caused salt retention and hypertension, along with stimulation of renin and suppression of renal cyclooxygenase 2, pointing to a contribution of endocrine and paracrine mechanisms at long term. In Brattleboro rats, CsA induced activation of NCC, but not NKCC2, and parallel effects were obtained in cultured cells in the absence of AVP. Stimulation of cultured thick ascending limb cells with AVP agonist restored their responsiveness to CsA. Our results suggest that the direct epithelial action of calcineurin inhibition is sufficient for the activation of NCC, whereas its effect on NKCC2 is more complex and requires concomitant stimulation by AVP. Copyright © 2017 the American Physiological Society.

  13. Estradiol reduces activity of the blood-brain barrier Na-K-Cl cotransporter and decreases edema formation in permanent middle cerebral artery occlusion.

    Science.gov (United States)

    O'Donnell, Martha E; Lam, Tina I; Tran, Lien Q; Foroutan, Shahin; Anderson, Steven E

    2006-10-01

    Estrogen has been shown to protect against stroke-induced brain damage, yet the mechanism is unknown. During the early hours of stroke, cerebral edema forms as increased transport of Na and Cl from blood into brain occurs across an intact blood-brain barrier (BBB). We showed previously that a luminal BBB Na-K-Cl cotransporter is stimulated by hypoxia and arginine vasopressin (AVP), factors present during cerebral ischemia, and that inhibition of the cotransporter by intravenous bumetanide greatly reduces edema in rats subjected to permanent middle cerebral artery occlusion (MCAO). The present study was conducted to determine whether estrogen protects in stroke at least in part by reducing activity of the BBB cotransporter, thereby decreasing edema formation. Ovariectomized rats were subjected to 210 mins of permanent MCAO after 7-day or 30-min pretreatment with 17beta-estradiol and then brain swelling and 2,3,5-triphenyltetrazolium chloride staining were assessed as measures of brain edema and lesion volume, respectively. Diffusion-weighed imaging was used to monitor permanent MCAO-induced decreases in apparent diffusion coefficient (ADC) values, an index of changes in brain water distribution and mobility. Na-K-Cl cotransporter activity of cerebral microvascular endothelial cells (CMECs) was assessed as bumetanide-sensitive K influx and cotransporter abundance by Western blot analysis after estradiol treatment. Estradiol significantly decreased brain swelling and lesion volume and attenuated the decrease in ADC values during permanent MCAO. Estradiol also abolished CMEC cotransporter stimulation by chemical hypoxia or AVP and decreased cotransporter abundance. These findings support the hypothesis that estrogen attenuates stimulation of BBB Na-K-Cl cotransporter activity, reducing edema formation during stroke.

  14. K-Cl Cotransporter 2–mediated Cl− Extrusion Determines Developmental Stage–dependent Impact of Propofol Anesthesia on Dendritic Spines

    KAUST Repository

    Puskarjov, Martin

    2017-03-16

    Background: General anesthetics potentiating γ-aminobutyric acid (GABA)-mediated signaling are known to induce a persistent decrement in excitatory synapse number in the cerebral cortex when applied during early postnatal development, while an opposite action is produced at later stages. Here, the authors test the hypothesis that the effect of general anesthetics on synaptogenesis depends upon the efficacy of GABA receptor type A (GABA A)-mediated inhibition controlled by the developmental up-regulation of the potassium-chloride (K-Cl) cotransporter 2 (KCC2). Methods: In utero electroporation of KCC2 was used to prematurely increase the efficacy of (GABA A)-mediated inhibition in layer 2/3 pyramidal neurons in the immature rat somatosensory cortex. Parallel experiments with expression of the inward-rectifier potassium channel Kir2.1 were done to reduce intrinsic neuronal excitability. The effects of these genetic manipulations (n = 3 to 4 animals per experimental group) were evaluated using iontophoretic injection of Lucifer Yellow (n = 8 to 12 cells per animal). The total number of spines analyzed per group ranged between 907 and 3,371. Results: The authors found a robust effect of the developmental up-regulation of KCC2-mediated Cl - transport on the age-dependent action of propofol on dendritic spines. Premature expression of KCC2, unlike expression of a transport-inactive KCC2 variant, prevented a propofol-induced decrease in spine density. In line with a reduction in neuronal excitability, the above result was qualitatively replicated by overexpression of Kir2.1. Conclusions: The KCC2-dependent developmental increase in the efficacy of GABA A -mediated inhibition is a major determinant of the age-dependent actions of propofol on dendritic spinogenesis.

  15. Hemoglobin Variants in Mice

    Energy Technology Data Exchange (ETDEWEB)

    Popp, Raymond A.

    1965-04-22

    Variability among mammalian hemoglobins was observed many years ago (35). The chemical basis for differences among hemoglobins from different species of mammals has been studied by several investigators (5, 11, 18, 48). As well as interspecies differences, hemoglobin variants are frequently found within a species of mammals (2, 3, 7, 16) The inheritance of these intraspecies variants can be studied, and pedigrees indicate that the type of hemoglobin synthesized in an individual is genetically controlled (20). Several of the variant human hemoglobins are f'unctionally deficient (7, 16). Such hemoglobin anomalies are of basic interest to man because of the vital role of hemoglobin for transporting oxygen to all tissues of the body.

  16. Allodynia and hyperalgesia in diabetic rats are mediated by GABA and depletion of spinal potassium-chloride co-transporters

    OpenAIRE

    2008-01-01

    Diabetic rats show behavioral indices of painful neuropathy that may model the human condition. Hyperalgesia during the formalin test in diabetic rats is accompanied by the apparently paradoxical decrease in spinal release of excitatory neurotransmitters and increase in the inhibitory neurotransmitter GABA. Decreased expression of the potassium-chloride co-transporter, KCC2, in the spinal cord promotes excitatory properties of GABA. We therefore measured spinal KCC2 expression and explored th...

  17. Expressions of ion co-transporter genes in salicylate-induced tinnitus and treatment effects of spirulina.

    Science.gov (United States)

    Hwang, Juen-Haur; Chan, Yin-Ching

    2016-09-02

    Although the activity of tinnitus-related ion co-transporter are known, their mRNA expressions has seldom been reported. We aimed to investigate the mRNA expressions of tinnitus-related ion co-transporter genes, and treatment effects of Spirulina. The mRNA expressions of K(+)-Cl(-) co-transporter (KCC2) and Na-K-2Cl co-transporter 1 (NKCC1) genes in the cochlea and brain of mice were evaluated after tinnitus was induced by intraperitoneal injection of salicylate. The effects of spirulina water extract on these gene expressions were investigated. Compared to the control group, the tinnitus scores increased significantly, however, the salicylate-induced tinnitus could be reduced significantly by spirulina water extract. The tinnitus group had higher of borderline significance mRNA expression of KCC2 gene in the cochlear, significantly higher in the temporal lobes and in the frontal lobes. Meanwhile, compared to the tinnitus group, the spirulina group had significantly lower mRNA expression of KCC2 gene in the cochlear, temporal lobes, frontal lobes and parahippocampus/hippocampus. However, the NKCC1 mRNA expression was not significantly different between three groups in the cochlea and these brain areas. Salicylate-induced tinnitus might be associated with increased mRNA expression of KCC2 gene, but not with mRNA expressions of NKCC1 gene in the cochlear and some tinnitus-related brain areas. Spirulina reduced the expression of KCC2 genes in salicylate-induced tinnitus.

  18. Loss of K-Cl co-transporter KCC3 causes deafness, neurodegeneration and reduced seizure threshold

    OpenAIRE

    Boettger, Thomas; Rust, Marco B.; Maier, Hannes; Seidenbecher, Thomas; Schweizer, Michaela; Damien J. Keating; Faulhaber, Jörg; Ehmke, Heimo; Pfeffer, Carsten; Scheel, Olaf; Lemcke, Beate; Horst, Jürgen; Leuwer, Rudolf; Pape, Hans-Christian; Völkl, Harald

    2003-01-01

    K-Cl co-transporters are encoded by four homologous genes and may have roles in transepithelial transport and in the regulation of cell volume and cytoplasmic chloride. KCC3, an isoform mutated in the human Anderman syndrome, is expressed in brain, epithelia and other tissues. To investigate the physiological functions of KCC3, we disrupted its gene in mice. This severely impaired cell volume regulation as assessed in renal tubules and neurons, and moderately raised intraneuronal Cl– concentr...

  19. Sodium Glucose Co-transporter Type 2 (SGLT2) Inhibitors: Targeting the Kidney to Improve Glycemic Control in Diabetes Mellitus

    OpenAIRE

    Bays, Harold

    2013-01-01

    Although hyperglycemia is a key therapeutic focus in the management of patients with type 2 diabetes mellitus (T2DM), many patients experience sub-optimal glycemic control. Current glucose-lowering agents involve the targeting of various body organs. Sodium glucose co-transporter type 2 (SGLT2) inhibitors target the kidney, reduce renal glucose reabsorption, and increase urinary glucose elimination, thus lowering glucose blood levels. This review examines some of the key efficacy and safety d...

  20. Benefits and Harms of Sodium-Glucose Co-Transporter 2 Inhibitors in Patients with Type 2 Diabetes

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Gluud, Lise L; Bennett, Cathy

    2016-01-01

    OBJECTIVE: Sodium-glucose co-transporter 2 inhibitors (SGLT2-i) are a novel drug class for the treatment of diabetes. We aimed at describing the maximal benefits and risks associated with SGLT2-i for patients with type 2 diabetes. DESIGN: Systematic review and meta-analysis. DATA SOURCES AND STUDY...... increased risk in non-serious adverse events. The analyses may overestimate the intervention benefit due bias....

  1. Determinants of Substrate and Cation Transport in the Human Na+/Dicarboxylate Cotransporter NaDC3*

    OpenAIRE

    Schlessinger, A; Sun, NN; Colas, C; Pajor, AM

    2014-01-01

    Metabolic intermediates, such as succinate and citrate, regulate important processes ranging from energy metabolism to fatty acid synthesis. Cytosolic concentrations of these metabolites are controlled, in part, by members of the SLC13 gene family. The molecular mechanism underlying Na+-coupled di- and tricarboxylate transport by this family is understood poorly. The human Na+/dicarboxylate cotransporter NaDC3 (SLC13A3) is found in various tissues, including the kidney, liver, and brain. In a...

  2. With no lysine L-WNK1 isoforms are negative regulators of the K+-Cl- cotransporters.

    Science.gov (United States)

    Mercado, Adriana; de Los Heros, Paola; Melo, Zesergio; Chávez-Canales, María; Murillo-de-Ozores, Adrián R; Moreno, Erika; Bazúa-Valenti, Silvana; Vázquez, Norma; Hadchouel, Juliette; Gamba, Gerardo

    2016-07-01

    The K(+)-Cl(-) cotransporters (KCC1-KCC4) encompass a branch of the SLC12 family of electroneutral cation-coupled chloride cotransporters that translocate ions out of the cell to regulate various factors, including cell volume and intracellular chloride concentration, among others. L-WNK1 is an ubiquitously expressed kinase that is activated in response to osmotic stress and intracellular chloride depletion, and it is implicated in two distinct hereditary syndromes: the renal disease pseudohypoaldosteronism type II (PHAII) and the neurological disease hereditary sensory neuropathy 2 (HSN2). The effect of L-WNK1 on KCC activity is unknown. Using Xenopus laevis oocytes and HEK-293 cells, we show that the activation of KCCs by cell swelling was prevented by L-WNK1 coexpression. In contrast, the activity of the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 was remarkably increased with L-WNK1 coexpression. The negative effect of L-WNK1 on the KCCs is kinase dependent. Elimination of the STE20 proline-alanine rich kinase (SPAK)/oxidative stress-responsive kinase (OSR1) binding site or the HQ motif required for the WNK-WNK interaction prevented the effect of L-WNK1 on KCCs, suggesting a required interaction between L-WNK1 molecules and SPAK. Together, our data support that NKCC1 and KCCs are coordinately regulated by L-WNK1 isoforms.

  3. Effect of Size-Selective Retention on the Cotransport of Hydroxyapatite and Goethite Nanoparticles in Saturated Porous Media.

    Science.gov (United States)

    Wang, Dengjun; Jin, Yan; Jaisi, Deb P

    2015-07-21

    Attributable to their nanoscale size and slow phosphorus (P) release kinetics, hydroxyapatite nanoparticles (HANPs) are increasingly advocated as a promising P nanofertilizer. Additionally, HANPs have been extensively used to remediate soils, groundwater, and nuclear wastewaters contaminated with metals and radionuclides. Increasing application of HANPs for agronomic and environmental advantages will expedite their dissemination in subsurface environments. Because the biogeochemical cycling of P is intimately coupled with iron, it is anticipated that HANPs and released P from HANPs interact with iron oxides, particularly naturally occurring goethite nanoparticles (GNPs) because of their nanoscale size and high reactivity toward P. Here, we investigated the cotransport and retention of HANPs and GNPs in water-saturated sand columns under environmentally relevant transport conditions (pH and natural organic matter type and concentration). Our results indicated that the "size-selective retention", i.e., preferential retention of larger particles near the column inlet and elution of smaller particles occurred during cotransport of HANPs and GNPs, and the cotransport of both NPs is highly sensitive to solution chemistry that determines NPs dissolution, homo- and heteroaggregation, and co- and competitive-retention. These findings have important insights into application of HANPs as a promising P nanofertilizer and an in situ amendment for contaminated site remediation.

  4. Clinical potential of sodium-glucose cotransporter 2 inhibitors in the management of type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Kim Y

    2012-08-01

    Full Text Available Yoojin Kim, Ambika R BabuDivision of Endocrinology, John Stroger Jr Hospital of Cook County and Rush University, Chicago, IL, USABackground: The kidney plays an important role in glucose metabolism, and has been considered a target for therapeutic intervention. The sodium-glucose cotransporter type 2 (SGLT2 mediates most of the glucose reabsorption from the proximal renal tubule. Inhibition of SGLT2 leads to glucosuria and provides a unique mechanism to lower elevated blood glucose levels in diabetes. The purpose of this review is to explore the physiology of SGLT2 and discuss several SGLT2 inhibitors which have clinical data in patients with type 2 diabetes.Methods: We performed a PubMed search using the terms "SGLT2" and "SGLT2 inhibitor" through April 10, 2012. Published articles, press releases, and abstracts presented at national and international meetings were considered.Results: SGLT2 inhibitors correct a novel pathophysiological defect, have an insulin-independent action, are efficacious with glycosylated hemoglobin reduction ranging from 0.5% to 1.5%, promote weight loss, have a low incidence of hypoglycemia, complement the action of other antidiabetic agents, and can be used at any stage of diabetes. They are generally well tolerated. However, due to side effects, such as repeated urinary tract and genital infections, increased hematocrit, and decreased blood pressure, appropriate patient selection for drug initiation and close monitoring after initiation will be important. Results of ongoing clinical studies of the effect of SGLT2 inhibitors on diabetic complications and cardiovascular safety are crucial to determine the risk-benefit ratio. A recent decision by the Committee for Medicinal Products for Human Use of the European Medicines Agency has recommended approval of dapagliflozin for the treatment of type 2 diabetes as an adjunct to diet and exercise, in combination with other glucose-lowering medicinal products, including

  5. Potassium channel and NKCC cotransporter involvement in ocular refractive control mechanisms.

    Directory of Open Access Journals (Sweden)

    Sheila G Crewther

    Full Text Available Myopia affects well over 30% of adult humans globally. However, the underlying physiological mechanism is little understood. This study tested the hypothesis that ocular growth and refractive compensation to optical defocus can be controlled by manipulation of potassium and chloride ion-driven transretinal fluid movements to the choroid. Chicks were raised with +/-10D or zero power optical defocus rendering the focal plane of the eye in front of, behind, or at the level of the retinal photoreceptors respectively. Intravitreal injections of barium chloride, a non-specific inhibitor of potassium channels in the retina and RPE or bumetanide, a selective inhibitor of the sodium-potassium-chloride cotransporter were made, targeting fluid control mechanisms. Comparison of refractive compensation to 5 mM Ba(2+ and 10(-5 M bumetanide compared with control saline injected eyes shows significant change for both positive and negative lens defocus for Ba(2+ but significant change only for negative lens defocus with bumetanide (Rx(SAL(-10D = -8.6 +/- .9 D; Rx(Ba2+(-10D = -2.9 +/- .9 D; Rx(Bum(-10D = -2.9 +/- .9 D; Rx(SAL(+10D = +8.2 +/- .9 D; Rx(Ba2+(+10D = +2.8 +/- 1.3 D; Rx(Bum(+10D = +8.0 +/- .7 D. Vitreous chamber depths showed a main effect for drug conditions with less depth change in response to defocus shown for Ba(2+ relative to Saline, while bumetanide injected eyes showed a trend to increased depth without a significant interaction with applied defocus. The results indicate that both K channels and the NKCC cotransporter play a role in refractive compensation with NKCC blockade showing far more specificity for negative, compared with positive, lens defocus. Probable sites of action relevant to refractive control include the apical retinal pigment epithelium membrane and the photoreceptor/ON bipolar synapse. The similarities between the biometric effects of NKCC inhibition and biometric reports of the blockade of the retinal ON response, suggest a

  6. Histone variants and lipid metabolism

    NARCIS (Netherlands)

    Borghesan, Michela; Mazzoccoli, Gianluigi; Sheedfar, Fareeba; Oben, Jude; Pazienza, Valerio; Vinciguerra, Manlio

    2014-01-01

    Within nucleosomes, canonical histones package the genome, but they can be opportunely replaced with histone variants. The incorporation of histone variants into the nucleosome is a chief cellular strategy to regulate transcription and cellular metabolism. In pathological terms, cellular steatosis

  7. Sodium-glucose co-transporter-2 inhibitors and euglycemic ketoacidosis: Wisdom of hindsight

    Directory of Open Access Journals (Sweden)

    Awadhesh Kumar Singh

    2015-01-01

    Full Text Available Sodium-glucose co-transporter-2 inhibitors (SGLT-2i are newly approved class of oral anti-diabetic drugs, in the treatment of type 2 diabetes, which reduces blood glucose through glucouresis via the kidney, independent, and irrespective of available pancreatic beta-cells. Studies conducted across their clinical development program found, a modest reduction in glycated hemoglobin ranging from −0.5 to −0.8%, without any significant hypoglycemia. Moreover, head-to-head studies versus active comparators yielded comparable efficacy. Interestingly, weight and blood pressure reduction were additionally observed, which was not only consistent but significantly superior to active comparators, including metformin, sulfonylureas, and dipeptydylpeptide-4 inhibitors. Indeed, these additional properties makes this class a promising oral anti-diabetic drug. Surprisingly, a potentially fatal unwanted side effect of diabetic ketoacidosis has been noted with its widespread use, albeit rarely. Nevertheless, this has created a passé among the clinicians. This review is an attempt to pool those ketosis data emerging with SGLT-2i, and put a perspective on its implicated mechanism.

  8. Sodium-glucose cotransporter 2 inhibitors with insulin in type 2 diabetes: Clinical perspectives

    Directory of Open Access Journals (Sweden)

    Mathew John

    2016-01-01

    Full Text Available The treatment of type 2 diabetes is a challenging problem. Most subjects with type 2 diabetes have progression of beta cell failure necessitating the addition of multiple antidiabetic agents and eventually use of insulin. Intensification of insulin leads to weight gain and increased risk of hypoglycemia. Sodium-glucose cotransporter 2 (SGLT2 inhibitors are a class of antihyperglycemic agents which act by blocking the SGLT2 in the proximal tubule of the kidney. They have potential benefits in terms of weight loss and reduction of blood pressure in addition to improvements in glycemic control. Further, one of the SGLT2 inhibitors, empagliflozin has proven benefits in reducing adverse cardiovascular (CV outcomes in a CV outcome trial. Adding SGLT2 inhibitors to insulin in subjects with type 2 diabetes produced favorable effects on glycemic control without the weight gain and hypoglycemic risks associated with insulin therapy. The general risks of increased genital mycotic infections, urinary tract infections, volume, and osmosis-related adverse effects in these subjects were similar to the pooled data of individual SGLT2 inhibitors. There are subsets of subjects with type 2 diabetes who may have insulin deficiency, beta cell autoimmunity, or is prone to diabetic ketoacidosis. In these subjects, SGLT2 inhibitors should be used with caution to prevent the rare risks of ketoacidosis.

  9. Characterization and comparison of sodium-glucose cotransporter 2 inhibitors in pharmacokinetics, pharmacodynamics, and pharmacologic effects

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    Atsuo Tahara

    2016-03-01

    Full Text Available The sodium-glucose cotransporter (SGLT 2 offer a novel approach to treating type 2 diabetes by reducing hyperglycaemia via increased urinary glucose excretion. In the present study, the pharmacokinetic, pharmacodynamic, and pharmacologic properties of all six SGLT2 inhibitors commercially available in Japan were investigated and compared. Based on findings in normal and diabetic mice, the six drugs were classified into two categories, long-acting: ipragliflozin and dapagliflozin, and intermediate-acting: tofogliflozin, canagliflozin, empagliflozin, and luseogliflozin. Long-acting SGLT2 inhibitors exerted an antihyperglycemic effect with lower variability of blood glucose level via a long-lasting increase in urinary glucose excretion. In addition, ipragliflozin and luseogliflozin exhibited superiority over the others with respect to fast onset of pharmacological effect. Duration and onset of the pharmacologic effects seemed to be closely correlated with the pharmacokinetic properties of each SGLT2 inhibitor, particularly with respect to high distribution and long retention in the target organ, the kidney. While all six SGLT2 inhibitors were significantly effective in increasing urinary glucose excretion and reducing hyperglycemia, our findings suggest that variation in the quality of daily blood glucose control associated with duration and onset of pharmacologic effects of each SGLT2 inhibitor might cause slight differences in rates of improvement in type 2 diabetes.

  10. Sodium glucose co-transporter inhibitors – A new class of old drugs

    Science.gov (United States)

    Malhotra, Aneeta; Kudyar, Surbhi; Gupta, Anil K.; Kudyar, Rattan P.; Malhotra, Pavan

    2015-01-01

    Sodium glucose co-transporter (SGLT) inhibitors are a new class of drugs which are used in the pharmacotherapy of Type-II diabetes, which happens to be a major risk factor for developing both micro as well as macro-vascular complications. These drugs inhibit the glucose reabsorption by inhibiting SGLT, which exhibits a novel and promising mechanism of action by promoting the urinary glucose excretion hence providing a basis of therapeutic intervention. Results of SGLT-II inhibitors are very encouraging as there is a significant elevation of GLP-1 level, which forms the basis of relevance in treatment of diabetes. It targets the HbA1C and keeps a check on its levels. It also exerts other positive benefits such as weight loss, reduction in blood glucose levels, reduction in blood pressure and improvement in insulin resistance and β-cell dysfunction: All contributing to effective glycemic control. SGLT inhibition will develop as effective modality as it has the capability of inhibiting reabsorption of greater percentage of filtered glucose load. PMID:26539362

  11. Blocking effect of colloids on arsenate adsorption during co-transport through saturated sand columns.

    Science.gov (United States)

    Ma, Jie; Guo, Huaming; Lei, Mei; Wan, Xiaoming; Zhang, Hanzhi; Feng, Xiaojuan; Wei, Rongfei; Tian, Liyan; Han, Xiaokun

    2016-06-01

    Transport of environmental pollutants through porous media is influenced by colloids. Co-transport of As(V) and soil colloids at different pH were systematically investigated by monitoring breakthrough curves (BTCs) in saturated sand columns. A solute transport model was applied to characterize transport and retention sites of As(V) in saturated sand in the presence of soil colloids. A colloid transport model and the DLVO theory were used to reveal the mechanism and hypothesis of soil colloid-promoted As(V) transport in the columns. Results showed that rapid transport of soil colloids, regulated by pH and ionic strength, promoted As(V) transport by blocking As(V) adsorption onto sand, although soil colloids had low adsorption for As(V). The promoted transport was more significant at higher concentrations of soil colloids (between 25 mg L(-1) and 150 mg L(-1)) due to greater blocking effect on As(V) adsorption onto the sand surfaces. The blocking effect of colloids was explained by the decreases in both instantaneous (equilibrium) As adsorption and first-order kinetic As adsorption on the sand surface sites. The discovery of this blocking effect improves our understanding of colloid-promoted As transport in saturated porous media, which provides new insights into role of colloids, especially colloids with low As adsorption capacity, in As transport and mobilization in soil-groundwater systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Abnormal expression of cerebrospinal fluid cation chloride cotransporters in patients with Rett syndrome.

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    Sofia Temudo Duarte

    Full Text Available OBJECTIVE: Rett Syndrome is a progressive neurodevelopmental disorder caused mainly by mutations in the gene encoding methyl-CpG-binding protein 2. The relevance of MeCP2 for GABAergic function was previously documented in animal models. In these models, animals show deficits in brain-derived neurotrophic factor, which is thought to contribute to the pathogenesis of this disease. Neuronal Cation Chloride Cotransporters (CCCs play a key role in GABAergic neuronal maturation, and brain-derived neurotrophic factor is implicated in the regulation of CCCs expression during development. Our aim was to analyse the expression of two relevant CCCs, NKCC1 and KCC2, in the cerebrospinal fluid of Rett syndrome patients and compare it with a normal control group. METHODS: The presence of bumetanide sensitive NKCC1 and KCC2 was analysed in cerebrospinal fluid samples from a control pediatric population (1 day to 14 years of life and from Rett syndrome patients (2 to 19 years of life, by immunoblot analysis. RESULTS: Both proteins were detected in the cerebrospinal fluid and their levels are higher in the early postnatal period. However, Rett syndrome patients showed significantly reduced levels of KCC2 and KCC2/NKCC1 ratio when compared to the control group. CONCLUSIONS: Reduced KCC2/NKCC1 ratio in the cerebrospinal fluid of Rett Syndrome patients suggests a disturbed process of GABAergic neuronal maturation and open up a new therapeutic perspective.

  13. Renal Expression and Urinary Excretion of Na-K-2Cl Cotransporter in Obstructive Nephropathy

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    Anabel Brandoni

    2017-01-01

    Full Text Available Renal damage due to urinary tract obstruction accounts for up to 30% of acute kidney injury in paediatrics and adults. Bilateral ureteral obstruction (BUO is associated with polyuria and reduced urinary concentrating capacity. We investigated the renal handling of water and electrolytes together with the renal expression and the urinary excretion of the Na-K-Cl cotransporter (NKCC2 after 1 (BUO-1, 2 (BUO-2, and 7 (BUO-7 days of release of BUO. Immunoblotting and immunohistochemical studies showed that NKCC2 expression was upregulated in apical membranes both from BUO-2 and from BUO-7 rats. The apical membrane expression, where NKCC2 is functional, may be sufficient to normalize water, potassium, sodium, and osmolytes tubular handling. NKCC2 abundance in homogenates and mRNA levels of NKCC2 was significantly decreased in almost all groups suggesting a decrease in the synthesis of the transporter. Urinary excretion of NKCC2 was increased in BUO-7 groups. These data suggest that the upregulation in the expression of NKCC2 in apical membranes during the postobstructive phase of BUO could contribute to improving the excretion of sodium and consequently also the excretion of potassium, osmolytes, and water. Moreover, the increase in urinary excretion of NKCC2 in BUO-7 group could be a potential additional biomarker of renal function recovery.

  14. Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill

    Science.gov (United States)

    Breves, Jason P.; Serizier, Sandy B.; Goffin, Vincent; McCormick, Stephen D.; Karlstrom, Rolf O.

    2013-01-01

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na+/Cl− cotransporter (ncc; slc12a10.2), Na+/H+ exchanger (nhe3b; slc9a3.2), and epithelial Ca2+ channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl− uptake in zebrafish for the first time.

  15. Na+-K+-2Cl- cotransporter type 2 trafficking and activity: the role of interacting proteins.

    Science.gov (United States)

    Carmosino, Monica; Procino, Giuseppe; Svelto, Maria

    2012-04-01

    The central role of Na+-K+-2Cl- cotransporter type 2 (NKCC2) in vectorial transepithelial salt reabsorption in thick ascending limb cells from Henle's loop in the kidney is evidenced by the effects of loop diuretics, the pharmacological inhibitors of NKCC2, that are amongst the most powerful antihypertensive drugs available to date. Moreover, genetic mutations of the NKCC2 encoding gene resulting in impaired apical targeting and function of NKCC2 transporter give rise to a pathological phenotype known as type I Bartter syndrome, characterised by a severe volume depletion, hypokalaemia and metabolic alkalosis with high prenatal mortality. On the contrary, excessive NKCC2 activity has been linked with inherited hypertension in humans and in rodent models. Interestingly, in animal models of hypertension, NKCC2 upregulation is achieved by post-translational mechanisms underlining the need to analyse the molecular mechanisms involved in the regulation of NKCC2 trafficking and activity to gain insights in the pathogenesis of hypertension. Copyright © 2012 Soçiété Francaise des Microscopies and Société de Biologie Cellulaire de France.

  16. Co-transport of metal complexes by the green mussel Perna viridis.

    Science.gov (United States)

    Chuang, Chia-Ying; Wang, Wen-Xiong

    2006-07-15

    We examined the uptake of ligand-bound metals (Cd and Zn) by the green mussel Perna viridis using defined artificial seawater. Different free ion concentrations (1 pM to 10 microM) in uptake solutions were created by adding different amounts of total metals (Cd 0.1 nM to 0.1 mM; Zn 0.5 nM to 0.05 mM) and ligands (EDTA, NTA, citric acid). Our results showed that Cd and Zn uptake could not be fully explained by the free Cd and Zn concentrations in the presence of different ligands, indicating that metal-ligand complexes were at least partially available for uptake by the mussels. Total Zn concentrations appeared to be a better predictor of metal uptake than the free Zn ion concentrations in the presence of different ligands. Uptake of lipophilic organic metal complexes was substantially greater than the hydrophilic metal complexes, even though the free ion concentration was comparable or lower. Moreover, the radiolabeled ligand compounds were directly accumulated by the mussels. The accumulation of metal complexes may explain the increased metal uptake with increasing ligand and total metal concentration, even though the free ion metal concentration was constant. Overall, our experimental results indicated that free metal ion cannot fully explain metal uptake since metal complex species were also available to the mussels to some extent, apparently through a co-transport process.

  17. Osmoregulation Requires Brain Expression of the Renal Na-K-2Cl Cotransporter NKCC2

    Science.gov (United States)

    Konopacka, Agnieszka; Qiu, Jing; Yao, Song T.; Greenwood, Michael P.; Greenwood, Mingkwan; Lancaster, Thomas; Inoue, Wataru; de Souza Mecawi, Andre; Vechiato, Fernanda M.V.; de Lima, Juliana B.M.; Coletti, Ricardo; Hoe, See Ziau; Martin, Andrew; Lee, Justina; Joseph, Marina; Hindmarch, Charles; Paton, Julian; Antunes-Rodrigues, Jose; Bains, Jaideep

    2015-01-01

    The Na-K-2Cl cotransporter 2 (NKCC2) was thought to be kidney specific. Here we show expression in the brain hypothalamo-neurohypophyseal system (HNS), wherein upregulation follows osmotic stress. The HNS controls osmotic stability through the synthesis and release of the neuropeptide hormone, arginine vasopressin (AVP). AVP travels through the bloodstream to the kidney, where it promotes water conservation. Knockdown of HNS NKCC2 elicited profound effects on fluid balance following ingestion of a high-salt solution—rats produced significantly more urine, concomitant with increases in fluid intake and plasma osmolality. Since NKCC2 is the molecular target of the loop diuretics bumetanide and furosemide, we asked about their effects on HNS function following disturbed water balance. Dehydration-evoked GABA-mediated excitation of AVP neurons was reversed by bumetanide, and furosemide blocked AVP release, both in vivo and in hypothalamic explants. Thus, NKCC2-dependent brain mechanisms that regulate osmotic stability are disrupted by loop diuretics in rats. PMID:25834041

  18. Protein kinase C induces endocytosis of the sodium taurocholate cotransporting polypeptide.

    Science.gov (United States)

    Stross, Claudia; Helmer, Angelika; Weissenberger, Katrin; Görg, Boris; Keitel, Verena; Häussinger, Dieter; Kubitz, Ralf

    2010-08-01

    Bile salts influence signaling and metabolic pathways. In hepatocytes, the sodium taurocholate cotransporting polypeptide (Ntcp) is a major determinant of intracellular bile salt levels. Short-term downregulation of Ntcp is not well characterized to date. FLAG and enhanced green fluorescent protein (EGFP) tags were cloned to the extra- and intracellular termini of Ntcp. Endocytosis of Ntcp in transfected HepG2 cells was visualized by fluorescence of EGFP, and membrane surface expression of Ntcp was quantified by flow cytometry with fluorochrome-labeled FLAG antibodies. Activation of protein kinase C (PKC) by phorbolester or thymeleatoxin an activator of Ca(2+)-dependent conventional PKCs (cPKCs), induced endocytosis of Ntcp, whereas the Na(+)-K(+)-ATPase remained in the plasma membrane. The PKC inhibitor BIM I and the cPKC-selective inhibitor Gö6976 abolished PMA-induced endocytosis. Because of this internalization, cell surface expression of Ntcp was reduced by 36 +/- 7%, bile salt uptake was decreased by 25%, and taurolithocholate sulfate-induced cell toxicity was prevented. In conclusion, Ca(2+)-dependent PKCs induce vesicular retrieval of Ntcp, thereby reducing bile salt uptake. This mechanism may protect hepatocytes from toxic intracellular bile salt concentrations.

  19. Renal glucose handling in diabetes and sodium glucose cotransporter 2 inhibition

    Directory of Open Access Journals (Sweden)

    Resham Raj Poudel

    2013-01-01

    Full Text Available The kidneys play a major role in glucose homeostasis through its utilization, gluconeogenesis, and reabsorption via sodium glucose cotransporters (SGLTs. The defective renal glucose handling from upregulation of SGLTs, mainly the SGLT2, plays a fundamental role in the pathogenesis of type 2 diabetes mellitus. Genetic mutations in a SGLT2 isoform that results in benign renal glycosuria, as well as clinical studies with SGLT2 inhibitors in type 2 diabetes support the potential of this approach. These studies indicate that inducing glycosuria by suppressing SGLT2 can reduce plasma glucose and A1c levels, as well as decrease weight, resulting in improved β-cell function and enhanced insulin sensitivity in liver and muscle. Because the mechanism of SGLT2 inhibition is independent of insulin secretion and sensitivity, these agents can be combined with other antidiabetic agents, including exogenous insulin. This class represents a novel therapeutic approach with potential for the treatment of both type 2 and type 1 diabetes.

  20. Sodium-glucose cotransporter inhibition: therapeutic potential for the treatment of type 2 diabetes mellitus.

    Science.gov (United States)

    Raskin, Philip

    2013-07-01

    Results from randomized controlled trials have demonstrated that the risk of microvascular complications can be reduced by intensive glycaemic control in patients with type 2 diabetes mellitus (T2DM). However, only about half of patients with diagnosed diabetes achieve recommended glycaemic goals. New therapies with complementary mechanisms of action that are independent of insulin secretion or action may provide additional therapeutic options to enable patients to achieve glycaemic control. The kidney plays an important role in glucose homeostasis, primarily by the reabsorption of filtered glucose. The sodium-glucose cotransporter 2 (SGLT2), located in the proximal convoluted tubule, is responsible for the majority of glucose reabsorption by the kidney. SGLT2 inhibitors offer a novel approach to treat T2DM and reduce hyperglycaemia by increasing urinary excretion of glucose. Dapagliflozin, an SGLT2 inhibitor recently approved in Europe for the treatment of T2DM, improves glycaemic control in patients with T2DM when used as monotherapy or when added to other diabetes medications, such as metformin, sulfonylureas, pioglitazone, and insulin. As a class, SGLT2 inhibitors are well tolerated and have a low propensity to cause hypoglycaemia. An increase in signs, symptoms, and other events suggestive of genital and, in some studies, urinary tract infections has been reported with SGLT2 inhibitors. Results from ongoing and future clinical trials will help define the role for this new class of investigational compounds, with its unique mechanism of action, as a treatment option for reducing hyperglycaemia in patients with T2DM.

  1. Drosophila glia use a conserved cotransporter mechanism to regulate extracellular volume.

    Science.gov (United States)

    Leiserson, William M; Forbush, Biff; Keshishian, Haig

    2011-02-01

    The nervous system is protected by blood barriers that use multiple systems to control extracellular solute composition, osmotic pressure, and fluid volume. In the human nervous system, misregulation of the extracellular volume poses serious health threats. Here, we show that the glial cells that form the Drosophila blood-nerve barrier have a conserved molecular mechanism that regulates extracellular volume: the Serine/Threonine kinase Fray, which we previously showed is an ortholog of mammalian PASK/SPAK; and the Na-K-Cl cotransporter Ncc69, which we show is an ortholog of human NKCC1. In mammals, PASK/SPAK binds to NKCC1 and regulates its activity. In Drosophila, larvae mutant for Ncc69 develop a peripheral neuropathy, where fluid accumulates between glia and axons. The accumulation of fluid has no detectable impact on action potential conduction, suggesting that the role of Ncc69 is to maintain volume or osmotic homeostasis. Drosophila Ncc69 has kinetics similar to human NKCC1, and NKCC1 can rescue Ncc69, suggesting that they function in a conserved physiological mechanism. We show that fray and Ncc69 are coexpressed in nerve glia, interact in a yeast-two-hybrid assay, and have an essentially identical bulging nerve phenotype. We propose that normally functioning nerves generate extracellular solutes that are removed by Ncc69 under the control of Fray. This mechanism may perform a similar role in humans, given that NKCC1 is expressed at the blood-brain barrier.

  2. [Canagliflozin (Invokana): kidney SGLT2 cotransporter inhibitor for treating type 2 diabetes].

    Science.gov (United States)

    Scheen, A J

    2014-12-01

    Canagliflozin is an inhibitor of sodium-glucose cotransporters type 2 (SGLT2) that are present in renal tubules. This specific insulin-independent mechanism promotes glucosuria, which results in a reduction in fasting and postprandial glycaemia and a decrease of glycated haemoglobin (HbA(1c)). Furthermore, canagliflozin promotes weight loss and lowers arterial (mainly systolic) blood pressure. Its efficacy is decreased in patients with renal insufficiency and the treatment should be stopped if estimated glomerular filtration rate is below 45 ml/min/1.73 m2. Both the efficacy and safety of canagliflozin have been investigated in 24 to 104-week controlled trials versus placebo or versus an active comparator (glimepiride or sitagliptin). The mean reduction in HbA(1c) averages 0.75% when added to other treatments, as compared to placebo. The 100 mg dose is as active as sitagliptin 100 mg while the 300 mg canagliflozin dose is even more efficacious. Adverse events are mostly mycotic genital infections and more rarely mild urinary tract infections. Caution is required in elderly patients and the risk of volume depletion should be checked (hypotension). Hypoglycaemia may occur only in patients already treated with an insulin-secreting agent or insulin. Canagliflozin is commercialized under the trade name Invokana, at the doses of 100 mg and 300 mg once daily, for the treatment of type 2 diabetes.

  3. Sodium-glucose co-transporter-2 inhibitors and euglycemic ketoacidosis: Wisdom of hindsight

    Science.gov (United States)

    Singh, Awadhesh Kumar

    2015-01-01

    Sodium-glucose co-transporter-2 inhibitors (SGLT-2i) are newly approved class of oral anti-diabetic drugs, in the treatment of type 2 diabetes, which reduces blood glucose through glucouresis via the kidney, independent, and irrespective of available pancreatic beta-cells. Studies conducted across their clinical development program found, a modest reduction in glycated hemoglobin ranging from −0.5 to −0.8%, without any significant hypoglycemia. Moreover, head-to-head studies versus active comparators yielded comparable efficacy. Interestingly, weight and blood pressure reduction were additionally observed, which was not only consistent but significantly superior to active comparators, including metformin, sulfonylureas, and dipeptydylpeptide-4 inhibitors. Indeed, these additional properties makes this class a promising oral anti-diabetic drug. Surprisingly, a potentially fatal unwanted side effect of diabetic ketoacidosis has been noted with its widespread use, albeit rarely. Nevertheless, this has created a passé among the clinicians. This review is an attempt to pool those ketosis data emerging with SGLT-2i, and put a perspective on its implicated mechanism. PMID:26693421

  4. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium–Glucose Cotransporter 2 Inhibition

    Science.gov (United States)

    Buschur, Elizabeth O.; Buse, John B.; Cohan, Pejman; Diner, Jamie C.; Hirsch, Irl B.

    2015-01-01

    OBJECTIVE Sodium–glucose cotransporter 2 (SGLT-2) inhibitors are the most recently approved antihyperglycemic medications. We sought to describe their association with euglycemic diabetic ketoacidosis (euDKA) in hopes that it will enhance recognition of this potentially life-threatening complication. RESEARCH DESIGN AND METHODS Cases identified incidentally are described. RESULTS We identified 13 episodes of SGLT-2 inhibitor–associated euDKA or ketosis in nine individuals, seven with type 1 diabetes and two with type 2 diabetes, from various practices across the U.S. The absence of significant hyperglycemia in these patients delayed recognition of the emergent nature of the problem by patients and providers. CONCLUSIONS SGLT-2 inhibitors seem to be associated with euglycemic DKA and ketosis, perhaps as a consequence of their noninsulin-dependent glucose clearance, hyperglucagonemia, and volume depletion. Patients with type 1 or type 2 diabetes who experience nausea, vomiting, or malaise or develop a metabolic acidosis in the setting of SGLT-2 inhibitor therapy should be promptly evaluated for the presence of urine and/or serum ketones. SGLT-2 inhibitors should only be used with great caution, extensive counseling, and close monitoring in the setting of type 1 diabetes. PMID:26078479

  5. The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate.

    Science.gov (United States)

    Mistry, Abinash C; Wynne, Brandi M; Yu, Ling; Tomilin, Viktor; Yue, Qiang; Zhou, Yiqun; Al-Khalili, Otor; Mallick, Rickta; Cai, Hui; Alli, Abdel A; Ko, Benjamin; Mattheyses, Alexa; Bao, Hui-Fang; Pochynyuk, Oleh; Theilig, Franziska; Eaton, Douglas C; Hoover, Robert S

    2016-10-01

    The thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC) are two of the most important determinants of salt balance and thus systemic blood pressure. Abnormalities in either result in profound changes in blood pressure. There is one segment of the nephron where these two sodium transporters are coexpressed, the second part of the distal convoluted tubule. This is a key part of the aldosterone-sensitive distal nephron, the final regulator of salt handling in the kidney. Aldosterone is the key hormonal regulator for both of these proteins. Despite these shared regulators and coexpression in a key nephron segment, associations between these proteins have not been investigated. After confirming apical localization of these proteins, we demonstrated the presence of functional transport proteins and native association by blue native PAGE. Extensive coimmunoprecipitation experiments demonstrated a consistent interaction of NCC with α- and γ-ENaC. Mammalian two-hybrid studies demonstrated direct binding of NCC to ENaC subunits. Fluorescence resonance energy transfer and immunogold EM studies confirmed that these transport proteins are within appropriate proximity for direct binding. Additionally, we demonstrate that there are functional consequences of this interaction, with inhibition of NCC affecting the function of ENaC. This novel finding of an association between ENaC and NCC could alter our understanding of salt transport in the distal tubule. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  6. Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill.

    Science.gov (United States)

    Breves, Jason P; Serizier, Sandy B; Goffin, Vincent; McCormick, Stephen D; Karlstrom, Rolf O

    2013-04-30

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na(+)/Cl(-) cotransporter (ncc; slc12a10.2), Na(+)/H(+) exchanger (nhe3b; slc9a3.2), and epithelial Ca(2+) channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl(-) uptake in zebrafish for the first time. Copyright © 2013. Published by Elsevier Ireland Ltd.

  7. Expression of Pit2 sodium-phosphate cotransporter during murine odontogenesis is developmentally regulated.

    Science.gov (United States)

    Zhao, Dawei; Vaziri Sani, Forugh; Nilsson, Jeanette; Rodenburg, Michaela; Stocking, Carol; Linde, Anders; Gritli-Linde, Amel

    2006-12-01

    Different sodium-dependent inorganic phosphate (P(i)) uptake mechanisms play a major role in cellular P(i) homeostasis. The function and detailed distribution patterns of the type III Na(+)-phosphate cotransporter, PiT-2, in different organs during development are still largely unknown. We therefore examined the temporospatial expression patterns of Pit2 during murine odontogenesis. Odontoblasts were always devoid of Pit2 expression, whereas a transient, but strong, expression was detected in young secretory ameloblasts. However, the stratum intermedium and, later on, the papillary layer and cells of the subodontoblastic layer, exhibited high levels of Pit2 mRNA, which increased gradually as the tooth matured. Hormonal treatment or P(i) starvation of tooth germs in vitro did not alter Pit2 levels or patterns of expression, indicating mechanisms of regulation different from those of PiT-1 or other cell types. PiT-2 also functions as a retroviral receptor, and functional membrane-localized protein was confirmed throughout the dental papilla/pulp by demonstrating cellular permissiveness to infection by a gammaretrovirus that uses PiT-2 as a receptor. The distinct pattern of Pit2 expression during odontogenesis suggests that its P(i)-transporter function may be important for homeostasis of dental cells and not specifically for mineralization of the dental extracellular matrices. The expression of viral receptors in enamel-forming cells and the dental pulp may be of pathological significance.

  8. Direct control of Na(+)-K(+)-2Cl(-)-cotransport protein (NKCC1) expression with aldosterone.

    Science.gov (United States)

    Ding, Bo; Frisina, Robert D; Zhu, Xiaoxia; Sakai, Yoshihisa; Sokolowski, Bernd; Walton, Joseph P

    2014-01-01

    Sodium/potassium/chloride cotransporter (NKCC1) proteins play important roles in Na(+) and K(+) concentrations in key physiological systems, including cardiac, vascular, renal, nervous, and sensory systems. NKCC1 levels and functionality are altered in certain disease states, and tend to decline with age. A sensitive, effective way of regulating NKCC1 protein expression has significant biotherapeutic possibilities. The purpose of the present investigation was to determine if the naturally occurring hormone aldosterone (ALD) could regulate NKCC1 protein expression. Application of ALD to a human cell line (HT-29) revealed that ALD can regulate NKCC1 protein expression, quite sensitively and rapidly, independent of mRNA expression changes. Utilization of a specific inhibitor of mineralocorticoid receptors, eplerenone, implicated these receptors as part of the ALD mechanism of action. Further experiments with cycloheximide (protein synthesis inhibitor) and MG132 (proteasome inhibitor) revealed that ALD can upregulate NKCC1 by increasing protein stability, i.e., reducing ubiquitination of NKCC1. Having a procedure for controlling NKCC1 protein expression opens the doors for therapeutic interventions for diseases involving the mis-regulation or depletion of NKCC1 proteins, for example during aging.

  9. Migraine Variants And Beyond

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    Chakravarty A

    2002-01-01

    Full Text Available The Classic presenting features of both migraine with and without aura have been clearly defined. Occasionally however migrainous headaches are accompanied by abrupt appearance of focal and ominous neurological signs. Such attacks can be labelled as migraine variants and the diagnosis in reality is one made by exclusion of other CNS diseases. Some but not all such conditions are mentioned in the International Headache Society (IHS classification under the general heading of migraine with aura. Rarely, the focal neurological deficit may outlast the migraine attack by days and occasionally with appearance of structural brain lesions on neuroimaging. Such attacks have been labelled as complicated Migraine by the IHS. The present review deal with the clinical, radiologic and pathophysiologic aspects of both these conditions - migraine variants and complicated migraine.

  10. Variants of Uncertainty

    Science.gov (United States)

    1981-05-15

    Variants of Uncertainty Daniel Kahneman University of British Columbia Amos Tversky Stanford University DTI-C &%E-IECTE ~JUNO 1i 19 8 1j May 15, 1981... Dennett , 1979) in which different parts have ac- cess to different data, assign then different weights and hold different views of the situation...2robable and t..h1 provable. Oxford- Claredor Press, 1977. Dennett , D.C. Brainstorms. Hassocks: Harvester, 1979. Donchin, E., Ritter, W. & McCallum, W.C

  11. Variants of glycoside hydrolases

    Energy Technology Data Exchange (ETDEWEB)

    Teter, Sarah; Ward, Connie; Cherry, Joel; Jones, Aubrey; Harris, Paul; Yi, Jung

    2017-07-11

    The present invention relates to variants of a parent glycoside hydrolase, comprising a substitution at one or more positions corresponding to positions 21, 94, 157, 205, 206, 247, 337, 350, 373, 383, 438, 455, 467, and 486 of amino acids 1 to 513 of SEQ ID NO: 2, and optionally further comprising a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2 a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2, wherein the variants have glycoside hydrolase activity. The present invention also relates to nucleotide sequences encoding the variant glycoside hydrolases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  12. Variants of glycoside hydrolases

    Energy Technology Data Exchange (ETDEWEB)

    Teter, Sarah (Davis, CA); Ward, Connie (Hamilton, MT); Cherry, Joel (Davis, CA); Jones, Aubrey (Davis, CA); Harris, Paul (Carnation, WA); Yi, Jung (Sacramento, CA)

    2011-04-26

    The present invention relates to variants of a parent glycoside hydrolase, comprising a substitution at one or more positions corresponding to positions 21, 94, 157, 205, 206, 247, 337, 350, 373, 383, 438, 455, 467, and 486 of amino acids 1 to 513 of SEQ ID NO: 2, and optionally further comprising a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2 a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2, wherein the variants have glycoside hydrolase activity. The present invention also relates to nucleotide sequences encoding the variant glycoside hydrolases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  13. ROS activate KCl cotransport in nonadherent Ehrlich ascites cells but K+ and Cl- channels in adherent Ehrlich Lettré and NIH3T3 cells

    DEFF Research Database (Denmark)

    Lambert, Ian Henry; Klausen, Thomas Kjær; Bergdahl, Andreas;

    2009-01-01

    the electrochemical driving force for K(+). On the other hand, the H2O2-induced cell shrinkage was impaired in the presence of the KCl cotransport inhibitor DIOA, following substitution of NO3(-) for Cl(-), and when the driving force for KCl cotransport was omitted. It is suggested that H2O2 activates electro neutral...

  14. Dapagliflozin Binds Specifically to Sodium-Glucose Cotransporter 2 in the Proximal Renal Tubule.

    Science.gov (United States)

    Ghezzi, Chiara; Yu, Amy S; Hirayama, Bruce A; Kepe, Vladimir; Liu, Jie; Scafoglio, Claudio; Powell, David R; Huang, Sung-Cheng; Satyamurthy, Nagichettiar; Barrio, Jorge R; Wright, Ernest M

    2017-03-01

    Kidneys contribute to glucose homeostasis by reabsorbing filtered glucose in the proximal tubules via sodium-glucose cotransporters (SGLTs). Reabsorption is primarily handled by SGLT2, and SGLT2-specific inhibitors, including dapagliflozin, canagliflozin, and empagliflozin, increase glucose excretion and lower blood glucose levels. To resolve unanswered questions about these inhibitors, we developed a novel approach to map the distribution of functional SGLT2 proteins in rodents using positron emission tomography with 4-[(18)F]fluoro-dapagliflozin (F-Dapa). We detected prominent binding of intravenously injected F-Dapa in the kidney cortexes of rats and wild-type and Sglt1-knockout mice but not Sglt2-knockout mice, and injection of SGLT2 inhibitors prevented this binding. Furthermore, imaging revealed only low levels of F-Dapa in the urinary bladder, even after displacement of kidney binding with dapagliflozin. Microscopic ex vitro autoradiography of kidney showed F-Dapa binding to the apical surface of early proximal tubules. Notably, in vivo imaging did not show measureable specific binding of F-Dapa in heart, muscle, salivary glands, liver, or brain. We propose that F-Dapa is freely filtered by the kidney, binds to SGLT2 in the apical membranes of the early proximal tubule, and is subsequently reabsorbed into blood. The high density of functional SGLT2 transporters detected in the apical membrane of the proximal tubule but not detected in other organs likely accounts for the high kidney specificity of SGLT2 inhibitors. Overall, these data are consistent with data from clinical studies on SGLT2 inhibitors and provide a rationale for the mode of action of these drugs. Copyright © 2017 by the American Society of Nephrology.

  15. Mutations in the Na-Cl cotransporter reduce blood pressure in humans.

    Science.gov (United States)

    Cruz, D N; Simon, D B; Nelson-Williams, C; Farhi, A; Finberg, K; Burleson, L; Gill, J R; Lifton, R P

    2001-06-01

    The relationship between salt homeostasis and blood pressure has remained difficult to establish from epidemiological studies of the general population. Recently, mendelian forms of hypertension have demonstrated that mutations that increase renal salt balance lead to higher blood pressure, suggesting that mutations that decrease the net salt balance might have the converse effect. Gitelman's syndrome, caused by loss of function mutations in the Na-Cl cotransporter of the distal convoluted tubule (NCCT), features inherited hypokalemic alkalosis with so-called "normal" blood pressure. We hypothesized that the mild salt wasting of Gitelman's syndrome results in reduced blood pressure and protection from hypertension. We have formally addressed this question through the study of 199 members of a large Amish kindred with Gitelman's syndrome. Through genetic testing, family members were identified as inheriting 0 (n=60), 1 (n=113), or 2 (n=26) mutations in NCCT, permitting an unbiased assessment of the clinical consequences of inheriting these mutations by comparison of the phenotypes of relatives with contrasting genotypes. The results demonstrate high penetrance of hypokalemic alkalosis, hypomagnesemia, and hypocalciuria in patients inheriting 2 mutant NCCT alleles. In addition, the NCCT genotype was a significant predictor of blood pressure, with homozygous mutant family members having significantly lower age- and gender-adjusted systolic and diastolic blood pressures than those of their wild-type relatives. Moreover, both homozygote and heterozygote subjects had significantly higher 24-hour urinary Na(+) than did wild-type subjects, reflecting a self-selected higher salt intake. Finally, heterozygous children, but not adults, had significantly lower blood pressures than those of the wild-type relatives. These findings provide formal demonstration that inherited mutations that impair renal salt handling lower blood pressure in humans.

  16. Heterozygous mutations of the sodium chloride cotransporter in Chinese children: prevalence and association with blood pressure.

    Science.gov (United States)

    Hsu, Yu-Juei; Yang, Sung-Sen; Chu, Nain-Feng; Sytwu, Huey-Kang; Cheng, Chih-Jen; Lin, Shih-Hua

    2009-04-01

    Gitelman's syndrome (GS), which is caused by homozygous or compound heterozygous mutations of the thiazide-sensitive sodium chloride cotransporter (NCC), usually manifests in children and is associated with low blood pressure. However, the prevalence of heterozygous NCC mutations and their association with blood pressure in children have not yet been studied. Five hundred unrelated children from the Taipei Children Heart Study were enrolled. Genomic DNA was isolated from peripheral blood and the SLC12A3 gene was amplified by polymerase chain reaction (PCR). The 15 NCC mutations previously identified in Chinese patients with GS were evaluated using restriction fragment length polymorphism (RFLP) analysis. Blood pressure, biochemistry and urine pH were measured. The allelic frequency of heterozygous NCC mutations and their association with low blood pressure were also investigated. RFLP analysis for the 15 NCC mutations revealed heterozygous T60M in 1 child, T163M in 1, S283Y in 4, R642C in 2, W844X in 2, R928C in 9 and R959frameshift in 10 children. The overall incidence of positive heterozygous NCC mutations was approximately 2.9%. There were no significant differences in systolic or diastolic blood pressure, biochemical profiles or urine pH between children with heterozygous NCC mutations (n = 29) and non-affected controls (n = 471), except for slightly higher fasting plasma glucose concentrations in NCC-heterozygous children (91 +/- 2.3 versus 88 +/- 0.4 mg/dL, P pressures. We found a relatively high prevalence of heterozygous NCC mutations in Chinese children, suggesting that GS may not be rare in this population. Heterozygous NCC mutations were not associated with lower blood pressure in these Chinese children.

  17. Age-dependent susceptibility to phenobarbital-resistant neonatal seizures: role of chloride co-transporters

    Directory of Open Access Journals (Sweden)

    Seok Kyu eKang

    2015-05-01

    Full Text Available Ischemia in the immature brain is an important cause of neonatal seizures. Temporal evolution of acquired neonatal seizures and their response to anticonvulsants are of great interest, given the unreliability of the clinical correlates and poor efficacy of first-line anti-seizure drugs. The expression and function of the electroneutral chloride co-transporters KCC2 and NKCC1 influence the anti-seizure efficacy of GABAA-agonists. To investigate ischemia-induced seizure susceptibility and efficacy of the GABAA-agonist phenobarbital (PB, with NKCC1 antagonist bumetanide (BTN as an adjunct treatment, we utilized permanent unilateral carotid-ligation to produce acute ischemic-seizures in postnatal day 7, 10 and 12 CD1 mice. Immediate post-ligation video-electroencephalograms (EEGs quantitatively evaluated baseline and post-treatment seizure burdens. Brains were examined for stroke-injury and western blot analyses to evaluate the expression of KCC2 and NKCC1. Severity of acute ischemic seizures post-ligation was highest at P7. PB was an efficacious anti-seizure agent at P10 and P12, but not at P7. BTN failed as an adjunct, at all ages tested and significantly blunted PB-efficacy at P10. Significant acute post-ischemic downregulation of KCC2 was detected at all ages. At P7, males displayed higher age-dependent seizure susceptibility, associated with a significant developmental lag in their KCC2 expression. This study established a novel neonatal mouse model of PB-resistant seizures that demonstrates age/sex-dependent susceptibility. The age-dependent profile of KCC2 expression and its post-insult downregulation may underlie the PB-resistance reported in this model. Blocking NKCC1 with low-dose BTN following PB treatment failed to improve PB-efficacy.

  18. Role of sodium glucose cotransporter-2 inhibitors in type I diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Ahmadieh H

    2017-05-01

    Full Text Available Hala Ahmadieh,1 Nisrine Ghazal,2 Sami T Azar3 1Faculty of Medicine, Clinical Sciences Department, Beirut Arab University, 2Department of Endocrinology and Metabolism, American University of Beirut, Beirut, Lebanon; 3Department of Internal Medicine, Division of Endocrinology, American University of Beirut, New York, NY, USA Abstract: The burden of diabetes mellitus (DM in general has been extensively increasing over the past few years. Selective sodium glucose cotransporter-2 (SGLT2 inhibitors were extensively studied in type 2 DM and found to have sustained urinary glucose loss, improvement of glycemic control, in addition to their proven metabolic effects on weight, blood pressure, and cardiovascular benefits. Type 1 DM (T1D patients clearly depend on insulin therapy, which till today fails to achieve the optimal glycemic control and metabolic targets that are needed to prevent risk of complications. New therapies are obviously needed as an adjunct to insulin therapy in order to try to achieve optimal control in T1D. Many oral diabetic medications have been tried in T1D patients as an adjunct to insulin treatment and have shown conflicting results. Adjunctive use of SGLT2 inhibitors in addition to insulin therapies in T1D was found to have the potential to improve glycemic control along with decrease in the insulin doses, as has been shown in certain animal and short-term human studies. Furthermore, larger well-randomized studies are needed to better evaluate their efficacy and safety in patients with T1D. Euglycemic diabetic ketoacidosis incidences were found to be increased among users of SGLT2 inhibitors, although the incidence remains very low. Recent beneficial effects of ketone body production and this shift in fuel energetics have been suggested based on the findings of protective cardiovascular benefits associated with one of the SGLT2 inhibitors. Keywords: glycemic control, glycosylated hemoglobin, euglucemic diabetic ketoacidosis

  19. Effect of Sodium-Glucose Cotransport Inhibition on Polycystic Kidney Disease Progression in PCK Rats.

    Directory of Open Access Journals (Sweden)

    Sarika Kapoor

    Full Text Available The sodium-glucose-cotransporter-2 (SGLT2 inhibitor dapagliflozin (DAPA induces glucosuria and osmotic diuresis via inhibition of renal glucose reabsorption. Since increased diuresis retards the progression of polycystic kidney disease (PKD, we investigated the effect of DAPA in the PCK rat model of PKD. DAPA (10 mg/kg/d or vehicle was administered by gavage to 6 week old male PCK rats (n=9 per group. Renal function, albuminuria, kidney weight and cyst volume were assessed after 6 weeks of treatment. Treatment with DAPA markedly increased glucose excretion (23.6 ± 4.3 vs 0.3 ± 0.1 mmol/d and urine output (57.3 ± 6.8 vs 19.3 ± 0.8 ml/d. DAPA-treated PCK rats had higher clearances for creatinine (3.1 ± 0.1 vs 2.6 ± 0.2 ml/min and BUN (1.7 ± 0.1 vs 1.2 ± 0.1 ml/min after 3 weeks, and developed a 4-fold increase in albuminuria. Ultrasound imaging and histological analysis revealed a higher cyst volume and a 23% higher total kidney weight after 6 weeks of DAPA treatment. At week 6 the renal cAMP content was similar between DAPA and vehicle, and staining for Ki67 did not reveal an increase in cell proliferation. In conclusion, the inhibition of glucose reabsorption with the SGLT2-specific inhibitor DAPA caused osmotic diuresis, hyperfiltration, albuminuria and an increase in cyst volume in PCK rats. The mechanisms which link glucosuria to hyperfiltration, albuminuria and enhanced cyst volume in PCK rats remain to be elucidated.

  20. Impact of sodium–glucose cotransporter 2 inhibitors on blood pressure

    Directory of Open Access Journals (Sweden)

    Reed JW

    2016-10-01

    control. Keywords: blood pressure, canagliflozin, dapagliflozin, empagliflozin, sodium–glucose cotransporter 2 inhibitors, type 2 diabetes

  1. Phosphorylation decreases ubiquitylation of the thiazide-sensitive cotransporter NCC and subsequent clathrin-mediated endocytosis.

    Science.gov (United States)

    Rosenbaek, Lena L; Kortenoeven, Marleen L A; Aroankins, Takwa S; Fenton, Robert A

    2014-05-09

    The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20-30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT.

  2. Effect of Sodium-Glucose Cotransport Inhibition on Polycystic Kidney Disease Progression in PCK Rats.

    Science.gov (United States)

    Kapoor, Sarika; Rodriguez, Daniel; Riwanto, Meliana; Edenhofer, Ilka; Segerer, Stephan; Mitchell, Katharyn; Wüthrich, Rudolf P

    2015-01-01

    The sodium-glucose-cotransporter-2 (SGLT2) inhibitor dapagliflozin (DAPA) induces glucosuria and osmotic diuresis via inhibition of renal glucose reabsorption. Since increased diuresis retards the progression of polycystic kidney disease (PKD), we investigated the effect of DAPA in the PCK rat model of PKD. DAPA (10 mg/kg/d) or vehicle was administered by gavage to 6 week old male PCK rats (n=9 per group). Renal function, albuminuria, kidney weight and cyst volume were assessed after 6 weeks of treatment. Treatment with DAPA markedly increased glucose excretion (23.6 ± 4.3 vs 0.3 ± 0.1 mmol/d) and urine output (57.3 ± 6.8 vs 19.3 ± 0.8 ml/d). DAPA-treated PCK rats had higher clearances for creatinine (3.1 ± 0.1 vs 2.6 ± 0.2 ml/min) and BUN (1.7 ± 0.1 vs 1.2 ± 0.1 ml/min) after 3 weeks, and developed a 4-fold increase in albuminuria. Ultrasound imaging and histological analysis revealed a higher cyst volume and a 23% higher total kidney weight after 6 weeks of DAPA treatment. At week 6 the renal cAMP content was similar between DAPA and vehicle, and staining for Ki67 did not reveal an increase in cell proliferation. In conclusion, the inhibition of glucose reabsorption with the SGLT2-specific inhibitor DAPA caused osmotic diuresis, hyperfiltration, albuminuria and an increase in cyst volume in PCK rats. The mechanisms which link glucosuria to hyperfiltration, albuminuria and enhanced cyst volume in PCK rats remain to be elucidated.

  3. Enhanced expression of potassium-chloride cotransporter KCC2 in human temporal lobe epilepsy.

    Science.gov (United States)

    Karlócai, Mária R; Wittner, Lucia; Tóth, Kinga; Maglóczky, Zsófia; Katarova, Zoja; Rásonyi, György; Erőss, Loránd; Czirják, Sándor; Halász, Péter; Szabó, Gábor; Payne, John A; Kaila, Kai; Freund, Tamás F

    2016-09-01

    Synaptic reorganization in the epileptic hippocampus involves altered excitatory and inhibitory transmission besides the rearrangement of dendritic spines, resulting in altered excitability, ion homeostasis, and cell swelling. The potassium-chloride cotransporter-2 (KCC2) is the main chloride extruder in neurons and hence will play a prominent role in determining the polarity of GABAA receptor-mediated chloride currents. In addition, KCC2 also interacts with the actin cytoskeleton which is critical for dendritic spine morphogenesis, and for the maintenance of glutamatergic synapses and cell volume. Using immunocytochemistry, we examined the cellular and subcellular levels of KCC2 in surgically removed hippocampi of temporal lobe epilepsy (TLE) patients and compared them to control human tissue. We also studied the distribution of KCC2 in a pilocarpine mouse model of epilepsy. An overall increase in KCC2-expression was found in epilepsy and confirmed by Western blots. The cellular and subcellular distributions in control mouse and human samples were largely similar; moreover, changes affecting KCC2-expression were also alike in chronic epileptic human and mouse hippocampi. At the subcellular level, we determined the neuronal elements exhibiting enhanced KCC2 expression. In epileptic tissue, staining became more intense in the immunopositive elements detected in control tissue, and profiles with subthreshold expression of KCC2 in control samples became labelled. Positive interneuron somata and dendrites were more numerous in epileptic hippocampi, despite severe interneuron loss. Whether the elevation of KCC2-expression is ultimately a pro- or anticonvulsive change, or both-behaving differently during ictal and interictal states in a context-dependent manner-remains to be established.

  4. Emerging roles of sodium-glucose cotransporter 2 inhibitors in cardiology.

    Science.gov (United States)

    Tanaka, Atsushi; Node, Koichi

    2017-03-01

    The ultimate goal of treatment in people with diabetes mellitus is to prevent development of cardiovascular (CV) disease, resulting in prolongation of healthy life expectancy. Although impaired glycemic metabolism has a central role in its pathology, a number of studies have demonstrated that remedy for its imbalance cannot necessarily be accomplished as a therapeutic goal. A comprehensive medical approach against multi-factorial pathologies in diabetes, such as insulin resistance, obesity, hypertension, and dyslipidemia, in addition to diet and exercise therapy should be rather performed in the routine clinical setting. Along with such conceptual transition, what is required in anti-diabetes agents has also changed, and several anti-diabetes agents have been newly placed on the market in this decade. Such agents are required to undergo global pre- or post-marketing clinical trials assessing CV safety. A growing body of clinical evidence from those trials is now accumulating, and empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has first demonstrated significant risk reduction, relative to placebo, in CV death, overall mortality, and hospitalization for worsened heart failure in high-risk patients with diabetes mellitus. An SGLT2 inhibitor is a unique glucose-lowering agent and at the same time has multifaceted effects on hemodynamic and metabolic parameters beyond glycemic control. A major mode of action of SGLT2 inhibitors appears to be 'glycosuria' and 'natriuresis,' leading to amelioration of systemic glycemic homeostasis and potential cardio-renal protection. However, the precise mechanisms by which SGLT2 inhibitors affect benefits on the CV systems are yet to be fully elucidated. Thus, although we are now facing several unanswered concerns lurking behind the successful trial, SGLT2 inhibitors surely play several important roles in high-quality management of not only diabetes, but also CV medicine. This review summarizes our current

  5. [EMPAGLIFLOZIN (JARDIANCE) :Nw SGLT2 COTRANSPORTER INHIBITOR FOR TREATING TYPE 2 DIABETES].

    Science.gov (United States)

    Scheen, A J

    2015-09-01

    Empagliflozin is a new inhibitor of sodiumglucose cotransporters type 2 (SGLT2) for the treatment of type 2 diabetes mellitus (T2DM). Its specific action inhibits glucose reabsorption in renal tubules and thus promotes glucosuria. This effect results in a reduction in fasting and postprandial glycaemia and a decrease of glycated haemoglobin (HbA(Ic)), independently of insulin. Furthermore, calorie urinary loss promotes weight reduction and osmotic diuresis lowers arterial blood pressure. The efficacy of empagliflozin increases according to the level of hyperglycaemia but decreases in patients with renal insufficiency. In 24 to 104-week controlled trials versus placebo, empagliflozin reduces HbA(1c) (approximately 0.8%), without hypoglycaemia (except in patients already treated with insulin or sulphonylureas). This improvement in glucose control is rather similar to that observed with active comparators (metformin, glimepiride or sitagliptin), with the advantage for empagliflozin of reducing body weight (approximately 2 kg) and blood pressure (systolic approximately 4 mm Hg and diastolic approximately 2 mm Hg). Empagliflozin has shown a cardiovascular protection in the EMPA-REG OUTCOME trial. Mycotic genital infections occur more frequently, especially in women, while a negligible increase in mild urinary tract infections may be observed. The risk of hypotension and volume depletion is low, although it should be carefully checked in more fragile and at risk patients. Empagliflozin (Jardiance), which is commercialized at the doses of 10 mg and 25 mg once daily, is indicated for the treatment of T2DM and reimbursed in Belgium with conditions as add-on to a background glucose-lowering therapy.

  6. Pharmacokinetic and pharmacodynamic profile of empagliflozin, a sodium glucose co-transporter 2 inhibitor.

    Science.gov (United States)

    Scheen, André J

    2014-03-01

    Empagliflozin is an orally active, potent and selective inhibitor of sodium glucose co-transporter 2 (SGLT2), currently in clinical development to improve glycaemic control in adults with type 2 diabetes mellitus (T2DM). SGLT2 inhibitors, including empagliflozin, are the first pharmacological class of antidiabetes agents to target the kidney in order to remove excess glucose from the body and, thus, offer new options for T2DM management. SGLT2 inhibitors exert their effects independently of insulin. Following single and multiple oral doses (0.5-800 mg), empagliflozin was rapidly absorbed and reached peak plasma concentrations after approximately 1.33-3.0 h, before showing a biphasic decline. The mean terminal half-life ranged from 5.6 to 13.1 h in single rising-dose studies, and from 10.3 to 18.8 h in multiple-dose studies. Following multiple oral doses, increases in exposure were dose-proportional and trough concentrations remained constant after day 6, indicating a steady state had been reached. Oral clearance at steady state was similar to corresponding single-dose values, suggesting linear pharmacokinetics with respect to time. No clinically relevant alterations in pharmacokinetics were observed in mild to severe hepatic impairment, or in mild to severe renal impairment and end-stage renal disease. Clinical studies did not reveal any relevant drug-drug interactions with several other drugs commonly prescribed to patients with T2DM, including warfarin. Urinary glucose excretion (UGE) rates were higher with empagliflozin versus placebo and increased with dose, but no relevant impact on 24-h urine volume was observed. Increased UGE resulted in proportional reductions in fasting plasma glucose and mean daily glucose concentrations.

  7. Phosphorylation Decreases Ubiquitylation of the Thiazide-sensitive Cotransporter NCC and Subsequent Clathrin-mediated Endocytosis*

    Science.gov (United States)

    Rosenbaek, Lena L.; Kortenoeven, Marleen L. A.; Aroankins, Takwa S.; Fenton, Robert A.

    2014-01-01

    The thiazide-sensitive sodium chloride cotransporter, NCC, is the major NaCl transport protein in the distal convoluted tubule (DCT). The transport activity of NCC can be regulated by phosphorylation, but knowledge of modulation of NCC trafficking by phosphorylation is limited. In this study, we generated novel tetracycline-inducible Madin-Darby canine kidney type I (MDCKI) cell lines expressing NCC to examine the role of NCC phosphorylation and ubiquitylation on NCC endocytosis. In MDCKI-NCC cells, NCC was highly glycosylated at molecular weights consistent with NCC monomers and dimers. NCC constitutively cycles to the apical plasma membrane of MDCKI-NCC cells, with 20–30% of the membrane pool of NCC internalized within 30 min. The use of dynasore, PitStop2, methyl-β-cyclodextrin, nystatin, and filipin (specific inhibitors of either clathrin-dependent or -independent endocytosis) demonstrated that NCC is internalized via a clathrin-mediated pathway. Reduction of endocytosis resulted in greater levels of NCC in the plasma membrane. Immunogold electron microscopy confirmed the association of NCC with the clathrin-mediated internalization pathway in rat DCT cells. Compared with controls, inducing phosphorylation of NCC via low chloride treatment or mimicking phosphorylation by replacing Thr-53, Thr-58, and Ser-71 residues with Asp resulted in increased membrane abundance and reduced rates of NCC internalization. NCC ubiquitylation was lowest in the conditions with greatest NCC phosphorylation, thus providing a mechanism for the reduced endocytosis. In conclusion, our data support a model where NCC is constitutively cycled to the plasma membrane, and upon stimulation, it can be phosphorylated to both increase NCC activity and decrease NCC endocytosis, together increasing NaCl transport in the DCT. PMID:24668812

  8. Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells.

    Science.gov (United States)

    Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna; Staub, Olivier; Fenton, Robert A

    2017-08-01

    The thiazide-sensitive sodium chloride cotransporter NCC is important for maintaining serum sodium (Na(+)) and, indirectly, serum potassium (K(+)) levels. Functional studies on NCC have used cell lines with native NCC expression, transiently transfected nonpolarized cell lines, or Xenopus laevis oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust thiazide-sensitive and chloride dependent sodium-22 ((22)Na) uptake from the apical side. To minimize cost and maximize throughput, assays were modified to use cells grown on plastic. On plastic, cells had similar thiazide-sensitive (22)Na uptakes that increased following preincubation of cells in chloride-free solutions. NCC was detected in the plasma membrane, and both membrane abundance and phosphorylation of NCC were increased by incubation in chloride-free solutions. Furthermore, in cells exposed for 15 min to low or high extracellular K(+), the levels of phosphorylated NCC increased and decreased, respectively. To demonstrate that the system allows rapid and systematic assessment of mutated NCC, three phosphorylation sites in NCC were mutated, and NCC activity was examined. (22)Na fluxes in phosphorylation-deficient mutants were reduced to baseline levels, whereas phosphorylation-mimicking mutants were constitutively active, even without chloride-free stimulation. In conclusion, this system allows the activity, cellular localization, and abundance of wild-type or mutant NCC to be examined in the same polarized mammalian expression system in a rapid, easy, and low-cost fashion. Copyright © 2017 the American Physiological Society.

  9. Potassium-chloride cotransporter 3 interacts with Vav2 to synchronize the cell volume decrease response with cell protrusion dynamics.

    Directory of Open Access Journals (Sweden)

    Adèle Salin-Cantegrel

    Full Text Available Loss-of-function of the potassium-chloride cotransporter 3 (KCC3 causes hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC, a severe neurodegenerative disease associated with defective midline crossing of commissural axons in the brain. Conversely, KCC3 over-expression in breast, ovarian and cervical cancer is associated with enhanced tumor cell malignancy and invasiveness. We identified a highly conserved proline-rich sequence within the C-terminus of the cotransporter which when mutated leads to loss of the KCC3-dependent regulatory volume decrease (RVD response in Xenopus Laevis oocytes. Using SH3 domain arrays, we found that this poly-proline motif is a binding site for SH3-domain containing proteins in vitro. This approach identified the guanine nucleotide exchange factor (GEF Vav2 as a candidate partner for KCC3. KCC3/Vav2 physical interaction was confirmed using GST-pull down assays and immuno-based experiments. In cultured cervical cancer cells, KCC3 co-localized with the active form of Vav2 in swelling-induced actin-rich protruding sites and within lamellipodia of spreading and migrating cells. These data provide evidence of a molecular and functional link between the potassium-chloride co-transporters and the Rho GTPase-dependent actin remodeling machinery in RVD, cell spreading and cell protrusion dynamics, thus providing new insights into KCC3's involvement in cancer cell malignancy and in corpus callosum agenesis in HMSN/ACC.

  10. Hyperexcitability and epilepsy associated with disruption of the mouse neuronal-specific K-Cl cotransporter gene.

    Science.gov (United States)

    Woo, Nam-Sik; Lu, Jianming; England, Roger; McClellan, Robert; Dufour, Samuel; Mount, David B; Deutch, Ariel Y; Lovinger, David M; Delpire, Eric

    2002-01-01

    Four genes encode electroneutral, Na+-independent, K-Cl cotransporters. KCC2, is exclusively expressed in neurons where it is thought to drive intracellular Cl- to low concentrations and shift the reversal potential for Cl- conductances such as GABA(A) or glycine receptor channels, thus participating in the postnatal development of inhibitory mechanisms in the brain. Indeed, expression of the cotransporter is low at birth and increases postnatally, at a time when the intracellular Cl- concentration in neurons decreases and gamma-aminobutyric acid switches its effect from excitatory to inhibitory. To assert the significance of KCC2 in neuronal function, we disrupted the mouse gene encoding this neuronal-specific K-Cl cotransporter. We demonstrate that animals deficient in KCC2 exhibit frequent generalized seizures and die shortly after birth. We also show upregulation of Fos, the product of the immediate early gene c-fos, and the significant loss of parvalbumin-positive interneurons, both indicative of brain injury. The regions most affected are the hippocampus and temporal and entorhinal cortices. Extracellular field potential measurements in the CA1 hippocampus exhibited hyperexcitability. Application of picrotoxin, a blocker of the GABA(A) receptor, further increased hyperexcitability in homozygous hippocampal sections. Pharmacological treatment of pups showed that diazepam relieved the seizures while phenytoin prevented them between postnatal ages P4-P12. Finally, we demonstrate that adult heterozygote animals show increased susceptibility for epileptic seizure and increased resistance to the anticonvulsant effect of propofol. Taken together, these results indicate that KCC2 plays an important role in controlling CNS excitability during both postnatal development and adult life.

  11. Cotransport of H+, lactate and H2O by membrane proteins in retinal pigment epithelium of bullfrog

    DEFF Research Database (Denmark)

    Zeuthen, T; Hamann, S; la Cour, M

    1996-01-01

    solution concentration and/or osmolarity. 3. Two parallel pathways for water transport were identified across the retinal membrane, an osmotic one with a hydraulic water permeability of 3.2 x 10(-4) cm s-1 (osmol l-1)-1 and one which depended on the presence of lactate. 4. Addition of sodium lactate...... the effect. The influx of water could proceed against osmotic gradients elicited by mannitol. 6. The interdependence of the fluxes of H+, lactate and H2O can be described as cotransport: the fluxes had a fixed ratio of about 109 mmol of lactic acid per litre of water, the flux of one species was able...

  12. Calcium oxalate crystal deposition in kidneys of hypercalciuric mice with disrupted type IIa sodium-phosphate cotransporter

    OpenAIRE

    Khan, Saeed R.; Glenton, Patricia A.

    2008-01-01

    The most common theories about the pathogenesis of idiopathic kidney stones consider precipitation of calcium phosphate (CaP) within the kidneys critical for the development of the disease. We decided to test the hypothesis that a CaP substrate can promote the deposition of calcium oxalate (CaOx) in the kidneys. Experimental hyperoxaluria was induced by feeding glyoxylate to male mice with knockout (KO) of NaPi IIa (Npt2a), a sodium-phosphate cotransporter. Npt2a KO mice are hypercalciuric an...

  13. Na+,2Cl-,K+ cotransport system as a marker of antihypertensive activity of new torasemide derivatives.

    Science.gov (United States)

    Masereel, B; Ferrari, P; Ferrandi, M; Pirotte, B; Schynts, M; Parenti, P; Delarge, J

    1992-09-04

    A series of compounds related to torasemide, a loop diuretic, were synthesized and examined for their diuretic potency and inhibitory activity on the erythrocyte and renal medullary thick ascending limb vesicle Na+,2Cl-,K+ cotransport in Milan hypertensive (MHS) and normotensive (MNS) rat strains, where previous studies had demonstrated an alteration of the cotransport system genetically related to hypertension. From the results of the screening, structure-activity relationships were drawn and two compounds, JDL 961 and C 2921 were selected. Their IC50 on renal vesicle cotransport were similar in the two strains (JDL 961: MHS = 1.8 microM; MNS = 1.2 microM; C 2921: MHS = 4 microM; MNS = 3.8 microM), and were 4-8 times lower than those of torasemide (MHS = 13 microM; MNS = 31 microM, P less than 0.01) and 50-60 times lower than those of bumetanide (MHS = 145 microM; MNS = 206 microM, P less than 0.05) taken as reference compounds. Their ability to reduce the development rate of hypertension was tested both in MHS and in Okamoto spontaneously hypertensive rats (SHR) strain, in which cotransport alterations are opposite to those of MHS. Both torasemide derivatives (7.5 mg.kg-1 os per day) prevented development of hypertension in the two strains. The time course of this hypotensive activity was faster and the percentage of blood pressure fall greater in MHS (20-25%) than in SHR rats (12-15%), even though the absolute value of blood pressure fall was similar in MHS (JDL 961 = -17 mm Hg; C 2921 = -30 mm Hg) and SHR (JDL 961 = -25 mm Hg; C 2921 = -20 mm Hg). A superimposable effect of bumetanide was observed in the two strains, but at 8 times higher daily dose (60 mg.kg-1). These results suggest that new loop diuretics can be selected for their antihypertensive activity on the basis of their in vitro potency in inhibiting the Na+,2Cl-,K+.

  14. Modular structure of sodium-coupled bicarbonate transporters

    Science.gov (United States)

    Boron, Walter F.; Chen, Liming; Parker, Mark D.

    2009-01-01

    Summary Mammalian genomes contain 10 SLC4 genes that, between them, encode three Cl–HCO3 exchangers, five Na+-coupled HCO3 transporters (NCBTs), one reported borate transporter, and what is reported to be a fourth Cl–HCO3 exchanger. The NCBTs are expressed throughout the body and play important roles in maintaining intracellular and whole-body pH, as well as contributing to transepithelial transport processes. The importance of NCBTs is underscored by the genetic association of dysfunctional NCBT genes with blindness, deafness, epilepsy, hypertension and metal retardation. Key to understanding the action and regulation of NCBTs is an appreciation of the diversity of NCBT gene products. The transmembrane domains of human NCBT paralogs are 50–84% identical to each other at the amino acid level, and are capable of a diverse range of actions, including electrogenic Na/HCO3 cotransport (i.e. NBCe1 and NBCe2) and electroneutral Na/HCO3 cotransport (i.e. NBCn1 and NBCn2), as well as Na+-dependent Cl–HCO3 exchange (i.e. NDCBE). Furthermore, by the use of alternative promoters and alternative-splicing events, individual SLC4 genes have the potential to generate multiple splice variants (as many as 16 in the case of NBCn1), each of which could have unique temporal and spatial patterns of distribution, unitary transporter activity (i.e. flux mediated by one molecule), array of protein-binding partners, and complement of regulatory stimuli. In the first section of this review, we summarize our present knowledge of the function and distribution of mammalian NCBTs and their multiple variants. In the second section of this review we consider the molecular consequences of NCBT variation. PMID:19448079

  15. Cotransport of hydroxyapatite nanoparticles and hematite colloids in saturated porous media: Mechanistic insights from mathematical modeling and phosphate oxygen isotope fractionation

    Science.gov (United States)

    Wang, Dengjun; Jin, Yan; Jaisi, Deb P.

    2015-11-01

    The fate and transport of individual type of engineered nanoparticles (ENPs) in porous media have been studied intensively and the corresponding mechanisms controlling ENPs transport and deposition are well-documented. However, investigations regarding the mobility of ENPs in the concurrent presence of another mobile colloidal phase such as naturally occurring colloids (colloid-mediated transport of ENPs) are largely lacking. Here, we investigated the cotransport and retention of engineered hydroxyapatite nanoparticles (HANPs) with naturally occurring hematite colloids in water-saturated sand columns under environmentally relevant transport conditions, i.e., pH, ionic strength (IS), and flow rate. Particularly, phosphate oxygen isotope fractionation of HANPs during cotransport was explored at various ISs and flow rates to examine the mechanisms controlling the isotope fractionation of HANPs in abiotic transport processes (physical transport). During cotransport, greater mobility of both HANPs and hematite occurred at higher pHs and flow rates, but at lower ISs. Intriguingly, the mobility of both HANPs and hematite was substantially lower during cotransport than the individual transport of either, attributed primarily to greater homo- and hetero-aggregation when both particles are copresent in the suspension. The shapes of breakthrough curves (BTCs) and retention profiles (RPs) during cotransport for both particles evolved from blocking to ripening with time and from flat to hyperexponential with depth, respectively, in response to decreases in pH and flow rate, and increases in IS. The blocking BTCs and RPs that are flat or hyperexponential can be well-approximated by a one-site kinetic attachment model. Conversely, a ripening model that incorporates attractive particle-particle interaction has to be employed to capture the ripening BTCs that are impacted by particle aggregation during cotransport. A small phosphate oxygen isotope fractionation (≤ 1.8

  16. Product Variant Master as a Means to Handle Variant Design

    DEFF Research Database (Denmark)

    Hildre, Hans Petter; Mortensen, Niels Henrik; Andreasen, Mogens Myrup

    1996-01-01

    The overall time requiered to design a new product variant relies on two factor: how good the methods to design the new variant are and how good these method are supported by computers.It has been estimated that 80% of all design tasks are variational in that the goal of the design is to adapt an...

  17. The renal thiazide-sensitive Na-Cl cotransporter as mediator of the aldosterone-escape phenomenon.

    Science.gov (United States)

    Wang, X Y; Masilamani, S; Nielsen, J; Kwon, T H; Brooks, H L; Nielsen, S; Knepper, M A

    2001-07-01

    The kidneys "escape" from the Na-retaining effects of aldosterone when circulating levels of aldosterone are inappropriately elevated in the setting of normal or expanded extracellular fluid volume, e.g., in primary aldosteronism. Using a targeted proteomics approach, we screened renal protein extracts with rabbit polyclonal antibodies directed to each of the major Na transporters expressed along the nephron to determine whether escape from aldosterone-mediated Na retention is associated with decreased abundance of one or more of renal Na transporters. The analysis revealed that the renal abundance of the thiazide-sensitive Na-Cl cotransporter (NCC) was profoundly and selectively decreased. None of the other apical solute-coupled Na transporters displayed decreases in abundance, nor were the total abundances of the three ENaC subunits significantly altered. Immunocytochemistry showed a strong decrease in NCC labeling in distal convoluted tubules of aldosterone-escape rats with no change in the cellular distribution of NCC. Ribonuclease protection assays (RPAs) revealed that the decrease in NCC protein abundance was not associated with altered NCC mRNA abundance. Thus, the thiazide-sensitive Na-Cl cotransporter of the distal convoluted tubule appears to be the chief molecular target for regulatory processes responsible for mineralocorticoid escape, decreasing in abundance via a posttranscriptional mechanism.

  18. Immunohistochemical localization of the Na-K-Cl co-transporter (NKCC1) in the gerbil inner ear.

    Science.gov (United States)

    Crouch, J J; Sakaguchi, N; Lytle, C; Schulte, B A

    1997-06-01

    We mapped the cellular and subcellular distribution of the Na-K-Cl co-transporter (NKCC) in the adult gerbil inner ear by immunostaining with a monoclonal antibody (MAb T4) generated against human colon NKCC. Heavy immunolabeling was seen in the basolateral plasma membrane of marginal cells in the stria vascularis and dark cells in the vestibular system. Subpopulations of fibrocytes in the cochlear spiral ligament and limbus and underlying the vestibular neurosensory epithelium also stained with moderate to strong intensity, apparently along their entire plasmalemma. Because MAb T4 recognizes both the basolateral secretory (NKCC1) and the apical absorptive (NKCC2) isoforms of the co-transporter, we employed reverse transcription and the polymerase chain reaction (RT-PCR) to explore isoform diversity in inner ear tissues. Using NKCC1 and NKCC2 isoform-specific PCR primers based on mouse and human sequences, only transcripts for NKCC1 were detected in the gerbil inner ear. The presence of abundant NKCC1 in the basolateral plasmalemma of strial marginal and vestibular dark cells confirms conclusions drawn from pharmacological and physiological data. The co-expression of NKCC1 and Na,K-ATPase in highly specialized subpopulations of cochlear and vestibular fibrocytes provides further evidence for their role in recycling K+ leaked or effluxed through hair cells into perilymph back to endolymph, as postulated in current models of inner ear ion homeostasis.

  19. The Thiazide-Sensitive Co-Transporter Promotes the Development of Sodium Retention in Mice with Diet-Induced Obesity

    Directory of Open Access Journals (Sweden)

    Matthew R P Davies

    2015-09-01

    Full Text Available Background/Aims: Intravascular volume expansion due to sodium retention is involved in the pathogenesis of obesity-related hypertension. Institution of high fat diet (HFD feeding leads to an initial state of positive sodium balance due to enhanced tubular reabsorption of sodium, but which tubular sodium transporters are responsible for this remains undefined. Methods: C57/Bl6 mice were fed control or HFD for 3 weeks. Blood pressures were recorded by tail cuff method. Sodium transporter expression and phosphorylation were determined by Western blotting. In vivo activity of NCC was determined using natriuretic responses to hydrochlorothiazide. Expression of NCC mRNA was determined using qPCR. Results: At 3 weeks HFD mice had significant weight gains compared to control mice, but blood pressures were not yet elevated. There were no changes in expression or phosphorylation of the bumetanide-sensitive cotransporter, NKCC2, or in expression of subunits of the amiloride-sensitive ion channel, ENaC. However, there were significant increases in mRNA and protein expression of the thiazide-sensitive co-transporter, NCC, in kidneys from HFD mice. Consistent with this, HFD mice had increased in vivo activity of NCC. Conclusions: Increased expression of NCC promotes the sodium loading response to institution of HFD feeding before onset of hypertension.

  20. Variants of windmill nystagmus.

    Science.gov (United States)

    Choi, Kwang-Dong; Shin, Hae Kyung; Kim, Ji-Soo; Kim, Sung-Hee; Choi, Jae-Hwan; Kim, Hyo-Jung; Zee, David S

    2016-07-01

    Windmill nystagmus is characterized by a clock-like rotation of the beating direction of a jerk nystagmus suggesting separate horizontal and vertical oscillators, usually 90° out of phase. We report oculographic characteristics in three patients with variants of windmill nystagmus in whom the common denominator was profound visual loss due to retinal diseases. Two patients showed a clock-like pattern, while in the third, the nystagmus was largely diagonal (in phase or 180° out of phase) but also periodically changed direction by 180°. We hypothesize that windmill nystagmus is a unique manifestation of "eye movements of the blind." It emerges when the central structures, including the cerebellum, that normally keep eye movements calibrated and gaze steady can no longer perform their task, because they are deprived of the retinal image motion that signals a need for adaptive recalibration.

  1. Luminal fructose inhibits rat intestinal sodium-phosphate cotransporter gene expression and phosphate uptake24

    Science.gov (United States)

    Kirchner, Séverine; Muduli, Anjali; Casirola, Donatella; Prum, Kannitha; Douard, Véronique; Ferraris, Ronaldo P

    2008-01-01

    Background While searching by microarray for sugar-responsive genes, we inadvertently discovered that sodium-phosphate cotransporter 2B (NaPi-2b) mRNA concentrations were much lower in fructose-perfused than in glucose-perfused intestines of neonatal rats. Changes in NaPi-2b mRNA abundance by sugars were accompanied by similar changes in NaPi-2b protein abundance and in rates of inorganic phosphate (Pi) uptake. Objective We tested the hypothesis that luminal fructose regulates NaPi-2b. Design We perfused into the intestine fructose, glucose, and non-metabolizable or poorly transported glucose analogs as well as phlorizin. Results NaPi-2b mRNA concentrations and Pi uptake rates in fructose-perfused intestines were ≈30% of those in glucose and its analogs. NaPi-2b inhibition by fructose is specific because the mRNA abundance and activity of the fructose transporter GLUT5 (glucose transporter 5) increased with fructose perfusion, whereas those of other transporters were independent of the perfusate. Plasma Pi after 4 h of perfusion was independent of the perfusate, probably because normal kidneys can maintain normophosphatemia. Inhibiting glucose-6-phosphatase, another fructose-responsive gene, with tungstate or vanadate nonspecifically inhibited NaPi-2b mRNA expression and Pi uptake in both glucose- or fructose-perfused intestines. The AMP kinase (AMPK)–activator AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) enhanced and the fatty acid synthase–AMPK inhibitor C75 (3-carboxy-4-octyl-2-methylene-butyrolactone trans-4-carboxy-5-octyl-3-methylenebutyrolactone) prevented fructose inhibition of NaPi-2b but had no effect on expression of other transporters. NaPi-2b expression decreased markedly with age and was inhibited by fructose in all age groups. Conclusions Energy levels in enterocytes may play a role in NaPi-2b inhibition by luminal fructose. Consumption of fructose that supplies ≈10% of caloric intake by Americans clearly affects absorption of

  2. Characterization of a novel phosphorylation site in the sodium–chloride cotransporter, NCC

    Science.gov (United States)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B; MacAulay, N; Fenton, R A

    2012-01-01

    The sodium–chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antibodies targeting pS124-NCC demonstrated a band of 160 kDa in the kidney cortex, but not medulla, which was preabsorbed by a corresponding phosphorylated peptide. Confocal microscopy with kidney tubule segment-specific markers localized pS124-NCC to all distal convoluted tubule cells. Double immunogold electron microscopy demonstrated that pS124-NCC co-localized with total NCC in the apical plasma membrane of distal convoluted tubule cells and intracellular vesicles. Acute treatment of Munich–Wistar rats or vasopressin-deficient Brattleboro rats with the vasopressin type 2 receptor-specific agonist dDAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin–angiotensin–aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1-related proline–alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and mTOR/FRAP) showed weak but significant phosphorylation activity at S124. In oocytes, 36Cl uptake studies combined with biochemical analysis showed decreased activity of plasma membrane-associated NCC when replacing S124 with alanine (A) or aspartic acid (D). In novel tetracycline-inducible MDCKII-NCC cell lines, S124A and S124D mutants were able to traffic to the plasma membrane similarly to wildtype NCC. PMID:22966159

  3. Characterization of a novel phosphorylation site in the sodium-chloride cotransporter, NCC.

    Science.gov (United States)

    Rosenbaek, L L; Assentoft, M; Pedersen, N B; MacAulay, N; Fenton, R A

    2012-12-01

    The sodium-chloride cotransporter, NCC, is essential for renal electrolyte balance. NCC function can be modulated by protein phosphorylation. In this study, we characterized the role and physiological regulation of a novel phosphorylation site in NCC at Ser124 (S124). Novel phospho-specific antibodies targeting pS124-NCC demonstrated a band of 160 kDa in the kidney cortex, but not medulla, which was preabsorbed by a corresponding phosphorylated peptide. Confocal microscopy with kidney tubule segment-specific markers localized pS124-NCC to all distal convoluted tubule cells. Double immunogold electron microscopy demonstrated that pS124-NCC co-localized with total NCC in the apical plasma membrane of distal convoluted tubule cells and intracellular vesicles. Acute treatment of Munich-Wistar rats or vasopressin-deficient Brattleboro rats with the vasopressin type 2 receptor-specific agonist dDAVP significantly increased pS124-NCC abundance, with no changes in total NCC plasma membrane abundance. pS124-NCC levels also increased in abundance in rats after stimulation of the renin-angiotensin-aldosterone system by dietary low sodium intake. In contrast to other NCC phosphorylation sites, the STE20/SPS1-related proline-alanine-rich kinase and oxidative stress-response kinases (SPAK and OSR1) were not able to phosphorylate NCC at S124. Protein kinase arrays identified multiple kinases that were able to bind to the region surrounding S124. Four of these kinases (IRAK2, CDK6/Cyclin D1, NLK and mTOR/FRAP) showed weak but significant phosphorylation activity at S124. In oocytes, (36)Cl uptake studies combined with biochemical analysis showed decreased activity of plasma membrane-associated NCC when replacing S124 with alanine (A) or aspartic acid (D). In novel tetracycline-inducible MDCKII-NCC cell lines, S124A and S124D mutants were able to traffic to the plasma membrane similarly to wildtype NCC.

  4. Histone variants and lipid metabolism

    NARCIS (Netherlands)

    Borghesan, Michela; Mazzoccoli, Gianluigi; Sheedfar, Fareeba; Oben, Jude; Pazienza, Valerio; Vinciguerra, Manlio

    2014-01-01

    Within nucleosomes, canonical histones package the genome, but they can be opportunely replaced with histone variants. The incorporation of histone variants into the nucleosome is a chief cellular strategy to regulate transcription and cellular metabolism. In pathological terms, cellular steatosis i

  5. Efficacy and Safety of Canagliflozin, an Inhibitor of Sodium-Glucose Cotransporter 2, When Used in Conjunction With Insulin Therapy in Patients With Type 2 Diabetes

    NARCIS (Netherlands)

    Neal, Bruce; Perkovic, Vlado; de Zeeuw, Dick; Mahaffey, Kenneth W.; Fulcher, Greg; Ways, Kirk; Desai, Mehul; Shaw, Wayne; Capuano, George; Alba, Maria; Jiang, Joel; Vercruysse, Frank; Meininger, Gary; Matthews, David

    OBJECTIVE There are limited data about the effects of sodium-glucose cotransporter 2 inhibitors when used with insulin. We report the efficacy and safety of canagliflozin in patients with type 2 diabetes using insulin. RESEARCH DESIGN AND METHODS The CANagliflozin CardioVascular Assessment Study is

  6. Water transport by Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS). The dependence of substrate size studied at high resolution

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Belhage, Bo; Zeuthen, Emil

    2005-01-01

    and osmosis at the membrane with diffusion in the cytoplasm. The combination of high resolution measurements and precise modelling showed that water transport across the membrane can be explained by cotransport of water in the membrane proteins and that intracellular unstirred layers effects are minute....

  7. Autosomal recessive hypophosphataemic rickets with hypercalciuria is not caused by mutations in the type II renal sodium/phosphate cotransporter gene.

    NARCIS (Netherlands)

    Heuvel, L.P.W.J. van den; Koul, K. Op de; Knots, E.; Knoers, N.V.A.M.; Monnens, L.A.H.

    2001-01-01

    BACKGROUND: At present the genetic defect for autosomal recessive and autosomal dominant hypophosphataemic rickets with hypercalciuria (HHRH) is unknown. Type II sodium/phosphate cotransporter (NPT2) gene is a serious candidate for being the causative gene in either or both autosomal recessive and a

  8. Relative contributions of Na+/H+ exchange and Na+/HCO3- cotransport to ischemic Na-i(+) overload in isolated rat hearts

    NARCIS (Netherlands)

    Ten Hove, M; Nederhoff, MGJ; Van Echteld, CJA

    2005-01-01

    The Na+/H+ exchanger (NHE) and/or the Na+/HCO3- cotransporter (NBC) were blocked during ischemia in isolated rat hearts. Intracellular Na+ concentration ([Na+](i)), intracellular pH (pH(i)), and energy-related phosphates were measured by using simultaneous Na-23 and P-31 NMR spectroscopy. Hearts wer

  9. Efficacy and Safety of Canagliflozin, an Inhibitor of Sodium-Glucose Cotransporter 2, When Used in Conjunction With Insulin Therapy in Patients With Type 2 Diabetes

    NARCIS (Netherlands)

    Neal, Bruce; Perkovic, Vlado; de Zeeuw, Dick; Mahaffey, Kenneth W.; Fulcher, Greg; Ways, Kirk; Desai, Mehul; Shaw, Wayne; Capuano, George; Alba, Maria; Jiang, Joel; Vercruysse, Frank; Meininger, Gary; Matthews, David

    2015-01-01

    OBJECTIVE There are limited data about the effects of sodium-glucose cotransporter 2 inhibitors when used with insulin. We report the efficacy and safety of canagliflozin in patients with type 2 diabetes using insulin. RESEARCH DESIGN AND METHODS The CANagliflozin CardioVascular Assessment Study is

  10. Cellobiohydrolase variants and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Wogulis, Mark

    2017-04-04

    The present invention relates to variants of a parent cellobiohydrolase II. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.

  11. Certain variants of multipermutohedron ideals

    Indian Academy of Sciences (India)

    AJAY KUMAR; CHANCHAL KUMAR

    2016-10-01

    Multipermutohedron ideals have rich combinatorial properties. An explicit combinatorial formula for the multigraded Betti numbers of a multipermutohedron ideal and their Alexander duals are known. Also, the dimension of the Artinian quotient of an Alexander dual of a multipermutohedron ideal is the number of generalized parking functions. In this paper, monomial ideals which are certain variants of multipermutohedron ideals are studied. Multigraded Betti numbers of these variant monomial ideals and their Alexander duals are obtained. Further, many interesting combinatorial properties of multipermutohedron ideals are extended to these variant monomial ideals.

  12. Disrupting Na+,HCO3--cotransporter NBCn1 (Slc4a7) delays murine breast cancer development

    DEFF Research Database (Denmark)

    Lee, S.; Axelsen, T. V.; Andersen, Anne Poder

    2016-01-01

    ) mice. Breast cancer histopathology in NBCn1 KO mice differed from that in WT mice and included less aggressive tumor types. The extracellular tumor microenvironment in NBCn1 KO mice contained higher concentrations of glucose and lower concentrations of lactate than that in WT mice. Independently......Increased metabolism and insufficient blood supply cause acidic waste product accumulation in solid cancers. During carcinogenesis, cellular acid extrusion is upregulated but the underlying molecular mechanisms and their consequences for cancer growth and progression have not been established....... Genome-wide association studies have indicated a possible link between the Na(+),HCO3(-)-cotransporter NBCn1 (SLC4A7) and breast cancer. We tested the functional consequences of NBCn1 knockout (KO) for breast cancer development. NBCn1 protein expression increased 2.5-fold during breast carcinogenesis...

  13. The effects of sodium-glucose co-transporter 2 inhibitors in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Gluud, Lise Lotte; Christensen, Mikkel

    2014-01-01

    to the knowledge regarding the beneficial and harmful effects of SGLT-2i in patients with type 2 diabetes. We plan to publish the study irrespective of the results. RESULTS: The study will be disseminated by peer-review publication and conference presentation. TRIAL REGISTRATION NUMBER: PROSPERO CRD42014008960......INTRODUCTION: Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) increase urinary glucose excretion through a reduced renal glucose reabsorption. We plan to perform a systematic review of SGLT-2i for treatment of type 2 diabetes. METHODS AND ANALYSIS: A systematic review with meta......-analyses of randomised clinical trials on SGLT-2i versus placebo, other oral glucose lowering drugs or insulin for patients with type 2 diabetes will be performed. The primary end point will be the glycated haemoglobin. Secondary end points will include changes in body weight, body mass index, fasting plasma glucose...

  14. Mutation of the Na-K-Cl co-transporter gene Slc12a2 results in deafness in mice.

    Science.gov (United States)

    Dixon, M J; Gazzard, J; Chaudhry, S S; Sampson, N; Schulte, B A; Steel, K P

    1999-08-01

    Hearing impairment is a common human condition, but we know little about the molecular basis of cochlear function. Shaker-with-syndactylism (sy) is a classic deaf mouse mutant and we show here that a second allele, sy(ns), is associated with abnormal production of endolymph, the fluid bathing sensory hair cells. Using a positional candidate approach, we demonstrate that mutations in the gene encoding the basolateral Na-K-Cl co-transporter Slc12a2 (Nkcc1, mBSC2) cause the deafness observed in sy and sy(ns) mice. This finding provides the molecular basis of another link in the chain of K+recycling in the cochlea, a process essential for normal cochlear function.

  15. Gene Variants Reduce Opioid Risks

    Science.gov (United States)

    ... Opioids Prescription Drugs & Cold Medicines Steroids (Anabolic) Synthetic Cannabinoids (K2/Spice) Synthetic Cathinones (Bath Salts) Tobacco/Nicotine ... variant of the gene for the μ-opioid receptor (OPRM1) with a decreased risk for addiction to ...

  16. Flozins, inhibitors of type 2 renal sodium-glucose co-transporter – not only antihyperglycemic drugs

    Directory of Open Access Journals (Sweden)

    Mizerski Grzegorz

    2015-09-01

    Full Text Available The kidneys play a crucial role in the regulation of the carbohydrate metabolism. In normal physiological conditions, the glucose that filters through the renal glomeruli is subsequently nearly totally reabsorbed in the proximal renal tubules. Two transporters are engaged in this process: sodium-glucose co-transporter type 1 (SGLT1, and sodium-glucose co-transporter type type 2 (SGLT2 - this being located in the luminal membrane of the renal tubular epithelial cells. It was found that the administration of dapagliflozin, a selective SGLT2 inhibitor, in patients with type 2 diabetes, is associated with the reduction of HbA1c concentration by 0.45-1.11%. Additional benefits from the treatment with dapagliflozin are the reduction of arterial blood pressure and a permanent reduction of body weight. This outcome is related to the effect of osmotic diuresis and to the considerable loss of the glucose load by way of urine excretion. Dapagliflozin may be successfully applied in type 2 diabetes monotherapy, as well as in combined therapy (including insulin, where it is equally effective as other oral anti-diabetic drugs. Of note: serious adverse effects of dapagliflozin administration are rarely observed. What is more, episodes of severe hypoglycaemia related with the treatment occur only sporadically, most often in the course of diabetes polytherapy. The most frequent effects of the SGLT2 inhibitors are inseparably associated with the mechanism of their action (the glucuretic effect, and cover urogenital infections with a mild clinical course. At present, clinical trials are being continued of the administration of several subsequent drugs from this group, the most advanced of these being the use of canagliflozin and empagliflozin.

  17. Cotransport of clay colloids and viruses through water-saturated vertically oriented columns packed with glass beads: Gravity effects.

    Science.gov (United States)

    Syngouna, Vasiliki I; Chrysikopoulos, Constantinos V

    2016-03-01

    The cotransport of clay colloids and viruses in vertically oriented laboratory columns packed with glass beads was investigated. Bacteriophages MS2 and ΦX174 were used as model viruses, and kaolinite (ΚGa-1b) and montmorillonite (STx-1b) as model clay colloids. A steady flow rate of Q=1.5 mL/min was applied in both vertical up (VU) and vertical down (VD) flow directions. In the presence of KGa-1b, estimated mass recovery values for both viruses were higher for VD than VU flow direction, while in the presence of STx-1b the opposite was observed. However, for all cases examined, the produced mass of viruses attached onto suspended clay particles were higher for VD than VU flow direction, suggesting that the flow direction significantly influences virus attachment onto clays, as well as packed column retention of viruses attached onto suspended clays. KGa-1b hindered the transport of ΦX174 under VD flow, while STx-1b facilitated the transport of ΦX174 under both VU and VD flow directions. Moreover, KGa-1b and STx-1b facilitated the transport of MS2 in most of the cases examined except of the case where KGa-1b was present under VD flow. Also, the experimental data were used for the estimation of virus surface-coverages and virus surface concentrations generated by virus diffusion-limited attachment, as well as virus attachment due to sedimentation. Both sedimentation and diffusion limited virus attachment were higher for VD than VU flow, except the case of MS2 and STx-1b cotransport. The diffusion-limited attachment was higher for MS2 than ΦΧ174 for all cases examined. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. ¬Immunolocalization of cation-chloride cotransporters in the developing and mature spinal cord of opossums, Monodelphis domestica

    Directory of Open Access Journals (Sweden)

    Ha-Loan ePhan

    2013-05-01

    Full Text Available Spinal inhibition is required to generate coordinated outputs between antagonistic muscles during locomotion. It relies on low neuronal chloride concentration set by two cation-chloride cotransporters, NKCC1 and KCC2 which, respectively, pumps Cl- in or out of neurons. It is generally accepted that NKCC1 is gradually inactivated during development, while KCC2 is upregulated and activated, resulting in low intracellular [Cl-]. Newborn opossums are very immature but perform rhythmic and alternate movements of the forelimbs to crawl on the mother’s belly and attach to a teat. Their hindlimbs are immobile. The alternation of the forelimbs suggests that mechanisms allowing spinal inhibition are present at birth. We studied the anatomical basis of inhibition in the spinal enlargements of postnatal opossums by immunolocalizing NKCC1 and KCC2. In some specimens, motoneurons and sensory afferents were labeled with TRDA prior to immunolabeling. At birth, both NKCC1 and KCC2 are detected in the presumptive grey and white matter of the ventral and the intermediolateral cord of both enlargements, but are sparse in the dorsal horn, where KCC2 is mostly seen on a small bundle of dendrites along primary afferents. KCC2 labeling is bright and has a mesh-like appearance in the grey matter and a radial appearance in the white matter, whereas NKCC1 is pale and diffuse. The subsequent expression of the cotransporters follows general ventrodorsal and mediolateral gradients, with the lumbar segments slightly lagging the cervical segments, until the mature pattern is observed around the 5th week. At all ages studied, KCC2 labeling is strong in the periphery of neurons. NKCC1 labeling decreases and becomes more uniformly distributed in the cells with age. Despite the significant anatomical and motor differences between the forelimbs and the hindlimbs of neonatal opossums, the maturation of KCC2 and NKCC1 is quite similar in both enlargements.

  19. PSD-95 interacts with NBCn1 and enhances channel-like activity without affecting Na/HCO(3) cotransport.

    Science.gov (United States)

    Lee, Soojung; Yang, Han Soo; Kim, Eunjin; Ju, Eun Ji; Kwon, Min Hyung; Dudley, R Kyle; Smith, Yoland; Yun, C Chris; Choi, Inyeong

    2012-01-01

    The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO(3)(-) movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO(3) cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO(3) cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed. Copyright © 2012 S. Karger AG, Basel.

  20. PSD-95 Interacts with NBCn1 and Enhances Channel-like Activity without Affecting Na/HCO3 Cotransport

    Science.gov (United States)

    Lee, Soojung; Yang, Han Soo; Kim, Eunjin; Ju, Eun Ji; Kwon, Min Hyung; Dudley, R. Kyle; Smith, Yoland; Yun, C. Chris; Choi, Inyeong

    2013-01-01

    Background/Aims The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO3− movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO3 cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. Methods: Results In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. Conclusion Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO3 cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed. PMID:23183381

  1. Inhibition by mercuric chloride of Na-K-2Cl cotransport activity in rectal gland plasma membrane vesicles isolated from Squalus acanthias.

    Science.gov (United States)

    Kinne-Saffran, E; Kinne, R K

    2001-02-09

    The rectal gland of the dogfish shark is a model system for active transepithelial transport of chloride. It has been shown previously that mercuric chloride, one of the toxic environmental pollutants, inhibits chloride secretion in this organ. In order to investigate the mechanism of action of HgCl(2) at a membrane-molecular level, plasma membrane vesicles were isolated from the rectal gland and the effect of mercury on the activity of the Na-K-2Cl cotransporter was investigated in isotope flux studies. During a 30 s exposure HgCl(2) inhibited cotransport activity in a dose-dependent manner with an apparent K(i) of approx. 50 microM. The inhibition was complete after 15 s, partly reversible by dilution of the incubation medium and completely attenuated upon addition of reduced glutathione. The extent of inhibition by mercury depended on the ionic composition of the medium. The sensitivity of the cotransporter was highest when only the high affinity binding sites for sodium and chloride were saturated. Organic mercurials such as p-chloromercuribenzoic acid and p-chloromercuriphenylsulfonic acid at 100 microM did not inhibit the cotransporter, similarly exposure of the vesicles to 10 mM H(2)O(2) or 1 mM dithiothreitol for 30 min at 15 degrees C did not change cotransport activity. Transport activity was, however, reduced by 45.9+/-2.5% after an incubation with 3 mM N-ethylmaleimide for 20 min. Blocking free amino groups by N-hydroxysuccinimide or biotinamidocapronate-N-hydroxysulfosuccinimide had no effect. Investigations on the sidedness of the plasma membrane vesicles, employing the asymmetry of the (Na+K)-ATPase, demonstrated a right-side-out orientation in which the former extracellular face of the membrane is exposed to the incubation medium. In addition, extracellular mercury (5x10(-5) M) inhibited bumetanide-sensitive rubidium uptake into T84 cells by 48.5+/-7.1% after a 2 min incubation period. This inhibition was reversible in a manner similar to that

  2. Bumetanide, an Inhibitor of NKCC1 (Na-K-2Cl Cotransporter Isoform 1), Enhances Propofol-Induced Loss of Righting Reflex but Not Its Immobilizing Actions in Neonatal Rats

    OpenAIRE

    Koyama, Yukihide; Andoh, Tomio; Kamiya, Yoshinori; Miyazaki, Tomoyuki; Maruyama, Koichi; Kariya, Takayuki; Goto, Takahisa

    2016-01-01

    Gamma-aminobutyric acid (GABA) has been shown to induce excitation on immature neurons due to increased expression of Na+-K+-2Cl- co-transporter isoform 1 (NKCC1), and the transition of GABAergic signaling from excitatory to inhibitory occurs before birth in the rat spinal cord and spreads rostrally according to the developmental changes in cation-chloride co-transporter expression. We previously showed that midazolam activates the hippocampal CA3 area and induces less sedation in neonatal ra...

  3. Pharmacodynamic Effects of Canagliflozin, a Sodium Glucose Co-Transporter 2 Inhibitor, from a Randomized Study in Patients with Type 2 Diabetes

    OpenAIRE

    Sue Sha; Damayanthi Devineni; Atalanta Ghosh; David Polidori; Marcus Hompesch; Sabine Arnolds; Linda Morrow; Heike Spitzer; Keith Demarest; Paul Rothenberg

    2014-01-01

    INTRODUCTION: This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes. METHODS: Patients (N = 116) discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in th...

  4. Euglycemic Diabetic Ketoacidosis in a 27 year-old female patient with type-1-Diabetes treated with sodium-glucose cotransporter-2 (SGLT2) inhibitor Canagliflozin

    OpenAIRE

    Bader, Nimrah; Mirza, Lubna

    2016-01-01

    We are reporting a timely case of atypical euglycemic diabetic ketoacidosis in a type 1 diabetic patient treated with sodium-glucose cotransporter-2 (SGLT-2) inhibitor canagliflozin. The clinical history, physical examination findings and laboratory values are described. Other causes of acidosis such as salicylate toxicity or alcohol intoxication were excluded. Ketoacidosis resolved after increasing dextrose and insulin doses supporting the hypothesis that SGLT-2 inhibitors may lead to hypoin...

  5. Data-variant kernel analysis

    CERN Document Server

    Motai, Yuichi

    2015-01-01

    Describes and discusses the variants of kernel analysis methods for data types that have been intensely studied in recent years This book covers kernel analysis topics ranging from the fundamental theory of kernel functions to its applications. The book surveys the current status, popular trends, and developments in kernel analysis studies. The author discusses multiple kernel learning algorithms and how to choose the appropriate kernels during the learning phase. Data-Variant Kernel Analysis is a new pattern analysis framework for different types of data configurations. The chapters include

  6. Variant Creutzfeldt-Jakob disease

    NARCIS (Netherlands)

    E.A. Croes (Esther); C.M. van Duijn (Cock)

    2003-01-01

    textabstractA variant form of Creutzfeldt-Jakob disease (vCJD) has had major impact in Europe during the last decade. In this article, we review the aetiology of vCJD and its relation with bovine spongiform encephalopathy. Further, treatment of the disease, the strategies focusing on prevention of t

  7. Sodium-glucose co-transporter 2 (SGLT2 inhibitors: a growing class of anti-diabetic agents

    Directory of Open Access Journals (Sweden)

    Eva M Vivian

    2014-12-01

    Full Text Available Although several treatment options are available to reduce hyperglycemia, only about half of individuals with diagnosed diabetes mellitus (DM achieve recommended glycemic targets. New agents that reduce blood glucose concentrations by novel mechanisms and have acceptable safety profiles are needed to improve glycemic control and reduce the complications associated with type 2 diabetes mellitus (T2DM. The renal sodium-glucose co-transporter 2 (SGLT2 is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors of SGLT2 lower blood glucose independent of the secretion and action of insulin by inhibiting renal reabsorption of glucose, thereby promoting the increased urinary excretion of excess glucose. Canagliflozin, dapagliflozin, and empagliflozin are SGLT2 inhibitors approved as treatments for T2DM in the United States, Europe, and other countries. Canagliflozin, dapagliflozin, and empagliflozin increase renal excretion of glucose and improve glycemic parameters in patients with T2DM when used as monotherapy or in combination with other antihyperglycemic agents. Treatment with SGLT2 inhibitors is associated with weight reduction, lowered blood pressure, and a low intrinsic propensity to cause hypoglycemia. Overall, canagliflozin, dapagliflozin, and empagliflozin are well tolerated. Cases of genital infections and, in some studies, urinary tract infections have been more frequent in canagliflozin-, dapagliflozin-, and empagliflozin-treated patients compared with those receiving placebo. Evidence from clinical trials suggests that SGLT2 inhibitors are a promising new treatment option for T2DM.

  8. Characterization and comparison of sodium-glucose cotransporter 2 inhibitors: Part 2. Antidiabetic effects in type 2 diabetic mice

    Directory of Open Access Journals (Sweden)

    Atsuo Tahara

    2016-07-01

    Full Text Available Previously we investigated the pharmacokinetic, pharmacodynamic, and pharmacologic properties of all six sodium-glucose cotransporter (SGLT 2 inhibitors commercially available in Japan using normal and diabetic mice. We classified the SGLT2 inhibitors with respect to duration of action as either long-acting (ipragliflozin and dapagliflozin or intermediate-acting (tofogliflozin, canagliflozin, empagliflozin, and luseogliflozin. In the present study, antidiabetic effects of repeated administration of these SGLT2 inhibitors in type 2 diabetic mice were investigated. When repeatedly administered for 4 weeks, all SGLT2 inhibitors significantly exhibited antihyperglycemic, antihyperinsulinemic, and pancreas-protective effects, as well as insulin resistance-improving effects. When compared at doses producing comparable reduction in hyperglycemia across all drugs, the antidiabetic effects of ipragliflozin and dapagliflozin were more potent than those of the other four drugs, but these differences among the six drugs were not statistically significant. Further, an oral glucose tolerance test performed after repeated administration demonstrated significant improvement in glucose tolerance only with ipragliflozin and dapagliflozin, implying improved insulin resistance and secretion. Taken together, these findings demonstrate that, although all SGLT2 inhibitors exert antidiabetic effects in type 2 diabetic mice, these pharmacologic effects might be slightly superior with the long-acting drugs, which are able to provide favorable blood glucose control throughout the day.

  9. Canagliflozin: a sodium glucose co-transporter 2 inhibitor for the treatment of type 2 diabetes mellitus.

    Science.gov (United States)

    Rosenthal, Norm; Meininger, Gary; Ways, Kirk; Polidori, David; Desai, Mehul; Qiu, Rong; Alba, Maria; Vercruysse, Frank; Balis, Dainius; Shaw, Wayne; Edwards, Robert; Bull, Scott; Di Prospero, Nicholas; Sha, Sue; Rothenberg, Paul; Canovatchel, William; Demarest, Keith

    2015-11-01

    The sodium glucose co-transporter 2 (SGLT2) inhibitor canagliflozin is a novel treatment option for adults with type 2 diabetes mellitus (T2DM). In patients with hyperglycemia, SGLT2 inhibition lowers plasma glucose levels by reducing the renal threshold for glucose (RTG ) and increasing urinary glucose excretion (UGE). Increased UGE is also associated with a mild osmotic diuresis and net caloric loss, which can lead to reductions in body weight and blood pressure (BP). After promising results from preclinical and phase I/II studies, the efficacy and safety of canagliflozin was evaluated in a comprehensive phase III development program in over 10,000 patients with T2DM on various background therapies. Canagliflozin improved glycemic control and provided reductions in body weight and BP versus placebo and active comparators in studies of up to 2 years' duration. Canagliflozin was generally well tolerated, with higher incidences of adverse events (AEs) related to the mechanism of action, including genital mycotic infections and AEs related to osmotic diuresis. Results from the preclinical and clinical studies led canagliflozin to be the first-in-class SGLT2 inhibitor approved in the United States, and support canagliflozin as a safe and effective therapeutic option across a broad range of patients with T2DM. © 2015 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

  10. The Na+/Glucose Cotransporter Inhibitor Canagliflozin Activates AMPK by Inhibiting Mitochondrial Function and Increasing Cellular AMP Levels.

    Science.gov (United States)

    Hawley, Simon A; Ford, Rebecca J; Smith, Brennan K; Gowans, Graeme J; Mancini, Sarah J; Pitt, Ryan D; Day, Emily A; Salt, Ian P; Steinberg, Gregory R; Hardie, D Grahame

    2016-09-01

    Canagliflozin, dapagliflozin, and empagliflozin, all recently approved for treatment of type 2 diabetes, were derived from the natural product phlorizin. They reduce hyperglycemia by inhibiting glucose reuptake by sodium/glucose cotransporter (SGLT) 2 in the kidney, without affecting intestinal glucose uptake by SGLT1. We now report that canagliflozin also activates AMPK, an effect also seen with phloretin (the aglycone breakdown product of phlorizin), but not to any significant extent with dapagliflozin, empagliflozin, or phlorizin. AMPK activation occurred at canagliflozin concentrations measured in human plasma in clinical trials and was caused by inhibition of Complex I of the respiratory chain, leading to increases in cellular AMP or ADP. Although canagliflozin also inhibited cellular glucose uptake independently of SGLT2, this did not account for AMPK activation. Canagliflozin also inhibited lipid synthesis, an effect that was absent in AMPK knockout cells and that required phosphorylation of acetyl-CoA carboxylase (ACC) 1 and/or ACC2 at the AMPK sites. Oral administration of canagliflozin activated AMPK in mouse liver, although not in muscle, adipose tissue, or spleen. Because phosphorylation of ACC by AMPK is known to lower liver lipid content, these data suggest a potential additional benefit of canagliflozin therapy compared with other SGLT2 inhibitors. © 2016 by the American Diabetes Association.

  11. Antioxidants and NOS inhibitors selectively targets manganese-induced cell volume via Na-K-Cl cotransporter-1 in astrocytes.

    Science.gov (United States)

    Alahmari, Khalid A; Prabhakaran, Harini; Prabhakaran, Krishnan; Chandramoorthy, Harish C; Ramugounder, Ramakrishnan

    2015-06-12

    Manganese has shown to be involved in astrocyte swelling. Several factors such as transporters, exchangers and ion channels are attributed to astrocyte swelling as a result in the deregulation of cell volume. Products of oxidation and nitration have been implied to be involved in the pathophysiology of swelling; however, the direct link and mechanism of manganese induced astrocyte swelling has not been fully elucidated. In the current study, we used rat primary astrocyte cultures to investigate the activation of Na-K-Cl cotransporter-1 (NKCC1) a downstream mechanism for free radical induced astrocyte swelling as a result of manganese toxicity. Our results showed manganese, oxidants and NO donors as potent inducer of oxidation and nitration of NKCC1. Our results further confirmed that manganese (50 μM) increased the total protein, phosphorylation and activity of NKCC1 as well as cell volume (p manganese or oxidants and NO induced activation, oxidation/nitration of NKCC1 play an important role in the astrocyte swelling. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Role of the neuronal K-Cl co-transporter KCC2 in inhibitory and excitatory neurotransmission

    Directory of Open Access Journals (Sweden)

    Ingrid eChamma

    2012-02-01

    Full Text Available The K-Cl co-transporter KCC2 plays multiple roles in the physiology of central neurons and alterations of its function and/or expression are associated with several neurological conditions. By regulating intraneuronal chloride homeostasis, KCC2 strongly influences the efficacy and polarity of the chloride-permeable -aminobutyric acid (GABA type A and glycine receptor (GlyR mediated synaptic transmission. This appears particularly critical for the development of neuronal circuits as well as for the dynamic control of GABA and glycine signaling in mature networks. The activity of the transporter is also associated with transmembrane water fluxes which compensate solute fluxes associated with synaptic activity. Finally, KCC2 interaction with the actin cytoskeleton appears critical both for dendritic spine morphogenesis and the maintenance of glutamatergic synapses. In light of the pivotal role of KCC2 in the maturation and function of central synapses, it is of particular importance to understand the cellular and molecular mechanisms underlying its regulation. These include development- and activity-dependent modifications both at the transcriptional and post-translational levels. We emphasize the importance of post-translational mechanisms such as phosphorylation and dephosphorylation, oligomerization, cell surface stability, clustering and membrane diffusion for the rapid and dynamic regulation of KCC2 function.

  13. Allodynia and hyperalgesia in diabetic rats are mediated by GABA and depletion of spinal potassium-chloride co-transporters

    Science.gov (United States)

    Jolivalt, Corinne G.; Lee, Corinne A.; Ramos, Khara M.; Calcutt, Nigel A.

    2008-01-01

    Diabetic rats show behavioral indices of painful neuropathy that may model the human condition. Hyperalgesia during the formalin test in diabetic rats is accompanied by the apparently paradoxical decrease in spinal release of excitatory neurotransmitters and increase in the inhibitory neurotransmitter GABA. Decreased expression of the potassium-chloride co-transporter, KCC2, in the spinal cord promotes excitatory properties of GABA. We therefore measured spinal KCC2 expression and explored the role of the GABAA receptor in rats with painful diabetic neuropathy. KCC2 protein levels were significantly reduced in the spinal cord of diabetic rats while levels of NKCC1 and the GABAA receptor were unchanged. Spinal delivery of the GABAA receptor antagonist bicuculline reduced formalin-evoked flinching in diabetic rats and also dose-dependently alleviated tactile allodynia. GABAA receptor-mediated rate-dependent depression of the spinal H reflex was absent in the spinal cord of diabetic rats. Control rats treated with the KCC2 blocker DIOA, mimicked diabetes by showing increased formalin-evoked flinching and diminished rate dependent depression. The ability of bicuculline to alleviate allodynia and formalin-evoked hyperalgesia in diabetic rats is consistent with a reversal of the properties of GABA predicted by reduced spinal KCC2 and suggests that reduced KCC2 expression and increased GABA release contribute to spinally-mediated hyperalgesia in diabetes. PMID:18755547

  14. Allodynia and hyperalgesia in diabetic rats are mediated by GABA and depletion of spinal potassium-chloride co-transporters.

    Science.gov (United States)

    Jolivalt, Corinne G; Lee, Corinne A; Ramos, Khara M; Calcutt, Nigel A

    2008-11-15

    Diabetic rats show behavioral indices of painful neuropathy that may model the human condition. Hyperalgesia during the formalin test in diabetic rats is accompanied by the apparently paradoxical decrease in spinal release of excitatory neurotransmitters and increase in the inhibitory neurotransmitter GABA. Decreased expression of the potassium-chloride co-transporter, KCC2, in the spinal cord promotes excitatory properties of GABA. We therefore measured spinal KCC2 expression and explored the role of the GABA(A) receptor in rats with painful diabetic neuropathy. KCC2 protein levels were significantly reduced in the spinal cord of diabetic rats, while levels of NKCC1 and the GABA(A) receptor were unchanged. Spinal delivery of the GABA(A) receptor antagonist bicuculline reduced formalin-evoked flinching in diabetic rats and also dose-dependently alleviated tactile allodynia. GABA(A) receptor-mediated rate-dependent depression of the spinal H reflex was absent in the spinal cord of diabetic rats. Control rats treated with the KCC2 blocker DIOA, mimicked diabetes by showing increased formalin-evoked flinching and diminished rate- dependent depression. The ability of bicuculline to alleviate allodynia and formalin-evoked hyperalgesia in diabetic rats is consistent with a reversal of the properties of GABA predicted by reduced spinal KCC2 and suggests that reduced KCC2 expression and increased GABA release contribute to spinally mediated hyperalgesia in diabetes.

  15. Co-transport of polycyclic aromatic hydrocarbons by motile microorganisms leads to enhanced mass transfer under diffusive conditions.

    Science.gov (United States)

    Gilbert, Dorothea; Jakobsen, Hans H; Winding, Anne; Mayer, Philipp

    2014-04-15

    The environmental chemodynamics of hydrophobic organic chemicals (HOCs) are often rate-limited by diffusion in stagnant boundary layers. This study investigated whether motile microorganisms can act as microbial carriers that enhance mass transfer of HOCs through diffusive boundary layers. A new experimental system was developed that allows (1) generation of concentration gradients of HOCs under the microscope, (2) exposure and direct observation of microorganisms in such gradients, and (3) quantification of HOC mass transfer. Silicone O-rings were integrated into a Dunn chemotaxis chamber to serve as sink and source for polycyclic aromatic hydrocarbons (PAHs). This resulted in stable concentration gradients in water (>24 h). Adding the model organism Tetrahymena pyriformis to the experimental system enhanced PAH mass transfer up to hundred-fold (benzo[a]pyrene). Increasing mass transfer enhancement with hydrophobicity indicated PAH co-transport with the motile organisms. Fluorescence microscopy confirmed such transport. The effective diffusivity of T. pyriformis, determined by video imaging microscopy, was found to exceed molecular diffusivities of the PAHs up to four-fold. Cell-bound PAH fractions were determined to range from 28% (naphthalene) to 92% (pyrene). Motile microorganisms can therefore function as effective carriers for HOCs under diffusive conditions and might significantly enhance mobility and availability of HOCs.

  16. Review. The mammalian proton-coupled peptide cotransporter PepT1: sitting on the transporter-channel fence?

    Science.gov (United States)

    Meredith, David

    2009-01-27

    The proton-coupled di- and tripeptide transporter PepT1 (SLC15a1) is the major route by which dietary nitrogen is taken up from the small intestine, as well as being the route of entry for important therapeutic (pro)drugs such as the beta-lactam antibiotics, angiotensin-converting enzyme inhibitors and antiviral and anti-cancer agents. PepT1 is a member of the major facilitator superfamily of 12 transmembrane domain transporter proteins. Expression studies in Xenopus laevis on rabbit PepT1 that had undergone site-directed mutagenesis of a conserved arginine residue (arginine282 in transmembrane domain 7) to a glutamate revealed that this residue played a role in the coupling of proton and peptide transport and prevented the movement of non-coupled ions during the transporter cycle. Mutations of arginine282 to other non-positive residues did not uncouple proton-peptide cotransport, but did allow additional ion movements when substrate was added. By contrast, mutations to positive residues appeared to function the same as wild-type. These findings are discussed in relation to the functional role that arginine282 may play in the way PepT1 operates, together with structural information from the homology model of PepT1 based on the Escherichia coli lactose permease crystal structure.

  17. A dileucine motif is involved in plasma membrane expression and endocytosis of rat sodium taurocholate cotransporting polypeptide (Ntcp).

    Science.gov (United States)

    Stross, Claudia; Kluge, Stefanie; Weissenberger, Katrin; Winands, Elisabeth; Häussinger, Dieter; Kubitz, Ralf

    2013-11-15

    The sodium taurocholate cotransporting polypeptide (Ntcp) is the major uptake transporter for bile salts into liver parenchymal cells, and PKC-mediated endocytosis was shown to regulate the number of Ntcp molecules at the plasma membrane. In this study, mechanisms of Ntcp internalization were analyzed by flow cytometry, immunofluorescence, and Western blot analyses in HepG2 cells. PKC activation induced endocytosis of Ntcp from the plasma membrane by ~30%. Endocytosis of Ntcp was clathrin dependent and was followed by lysosomal degradation. A dileucine motif located in the third intracellular loop of Ntcp was essential for endocytosis but also for processing and plasma membrane targeting, suggesting a dual function of this motif for intracellular trafficking of Ntcp. Mutation of two of five potential phosphorylation sites surrounding the dileucine motif (Thr225 and Ser226) inhibited PKC-mediated endocytosis. In conclusion, we could identify a motif, which is critical for Ntcp plasma membrane localization. Endocytic retrieval protects hepatocytes from elevated bile salt concentrations and is of special interest, because NTCP has been identified as a receptor for the hepatitis B and D virus.

  18. Place of sodium-glucose co-transporter type 2 inhibitors for treatment of type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    Nasser; Mikhail

    2014-01-01

    Inhibitors of sodium-glucose co-transporter type 2(SGLT2), such as canagliflozin and dapagliflozin, are recently approved for treatment of type 2 diabetes. These agents lower blood glucose mainly by increasing urinary glucose excretion. Compared with placebo, SGLT2 inhibitors reduce hemoglobin A1c(Hb A1c) levels by an average of 0.5%-0.8% when used as monotherapy or add-on therapy. Advantages of this drug class include modest weight loss of approximately 2 kg, low risk of hypoglycemia, and decrease blood pressure of approximately 4 mm Hg systolic and 2 mm Hg diastolic. These characteristics make these agents potential add-on therapy in patients with Hb A1 c levels close to 7%-8.0%, particularly if these patients are obese, hypertensive, and/or prone for hypoglycemia. Meanwhile, these drugs are limited by high frequency of genital mycotic infections. Less common adverse effects include urinary tract infections, hypotension, dizziness, and worsening renal function. SGLT2 inhibitors should be used with caution in the elderly because of increased adverse effects, and should not be used in chronic kidney disease due to decreased or lack of efficacy and nephrotoxicity. Overall, SGLT2 inhibitors are useful addition for treatment of select groups of patients with type 2 diabetes,but their efficacy and safety need to be established in long-term clinical trials.

  19. Dietary salt regulates the phosphorylation of OSR1/SPAK kinases and the sodium chloride cotransporter through aldosterone.

    Science.gov (United States)

    Chiga, Motoko; Rai, Tatemitsu; Yang, Sung-Sen; Ohta, Akihito; Takizawa, Toichiro; Sasaki, Sei; Uchida, Shinichi

    2008-12-01

    Pseudohypoaldosteronism type II (PHAII) is caused by mutations in the WNK1 and WNK4 genes (WNK with-no-lysine kinase). In a mouse model of this disease where a mutant of Wnk4 D561A was knocked in, increased phosphorylation of the sodium chloride cotransporter (NCC) was found and the transporter was concentrated on the apical membrane of the distal tubules. In addition, we recently found that other kinases, such as the oxidative stress response kinase-1/STE20/SPS1-related proline alanine-rich kinase (OSR1/SPAK), also showed increased phosphorylation in these mice. Here we determined whether this kinase cascade is regulated by dietary salt intake. We found that the phosphorylation states of NCC and OSR1/SPAK were increased by low-salt diets and decreased by high-salt diets; a regulation completely lost in the knock-in mice. Increased phosphorylation was reversed by spironolactone and this decreased phosphorylation was reversed by administration of exogenous aldosterone. These studies suggest that that the WNK-OSR1/SPAK-NCC cascade may be a novel effector system of aldosterone action in the kidney.

  20. Loss of K-Cl co-transporter KCC3 causes deafness, neurodegeneration and reduced seizure threshold.

    Science.gov (United States)

    Boettger, Thomas; Rust, Marco B; Maier, Hannes; Seidenbecher, Thomas; Schweizer, Michaela; Keating, Damien J; Faulhaber, Jörg; Ehmke, Heimo; Pfeffer, Carsten; Scheel, Olaf; Lemcke, Beate; Horst, Jürgen; Leuwer, Rudolf; Pape, Hans-Christian; Völkl, Harald; Hübner, Christian A; Jentsch, Thomas J

    2003-10-15

    K-Cl co-transporters are encoded by four homologous genes and may have roles in transepithelial transport and in the regulation of cell volume and cytoplasmic chloride. KCC3, an isoform mutated in the human Anderman syndrome, is expressed in brain, epithelia and other tissues. To investigate the physiological functions of KCC3, we disrupted its gene in mice. This severely impaired cell volume regulation as assessed in renal tubules and neurons, and moderately raised intraneuronal Cl(-) concentration. Kcc3(-/-) mice showed severe motor abnormalities correlating with a progressive neurodegeneration in the peripheral and CNS. Although no spontaneous seizures were observed, Kcc3(-/-) mice displayed reduced seizure threshold and spike-wave complexes on electrocorticograms. These resembled EEG abnormalities in patients with Anderman syndrome. Kcc3(-/-) mice also displayed arterial hypertension and a slowly progressive deafness. KCC3 was expressed in many, but not all cells of the inner ear K(+) recycling pathway. These cells slowly degenerated, as did sensory hair cells. The present mouse model has revealed important cellular and systemic functions of KCC3 and is highly relevant for Anderman syndrome.

  1. Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4.

    Science.gov (United States)

    Boettger, Thomas; Hübner, Christian A; Maier, Hannes; Rust, Marco B; Beck, Franz X; Jentsch, Thomas J

    2002-04-25

    Hearing depends on a high K(+) concentration bathing the apical membranes of sensory hair cells. K(+) that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media(). K(+) probably exits outer hair cells by KCNQ4 K(+) channels(), and is then transported by means of a gap junction system connecting supporting Deiters' cells and fibrocytes() back to the stria vascularis. We show here that mice lacking the K(+)/Cl(-) (K-Cl) co-transporter Kcc4 (coded for by Slc12a7) are deaf because their hair cells degenerate rapidly after the beginning of hearing. In the mature organ of Corti, Kcc4 is restricted to supporting cells of outer and inner hair cells. Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway. Similar to some human genetic syndromes(), deafness in Kcc4-deficient mice is associated with renal tubular acidosis. It probably results from an impairment of Cl(-) recycling across the basolateral membrane of acid-secreting alpha-intercalated cells of the distal nephron.

  2. Renal Safety of Canagliflozin, a Sodium Glucose Co-transporter 2 Inhibitor, in Patients With Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Desai, Mehul; Yavin, Yshai; Balis, Dainius; Sun, Don; Xie, John; Canovatchel, William; Rosenthal, Norm

    2017-01-12

    The incidence of renal-related adverse events (AEs) with canagliflozin in patients with type 2 diabetes mellitus from a pooled population of patients in 7 active- and placebo-controlled trials (N = 5,598) and in a 104-week study versus glimepiride (N = 1,450) was low and similar in canagliflozin and non-canagliflozin groups. In the study versus glimepiride, canagliflozin was associated with an initial acute decrease in estimated glomerular filtration rate (eGFR) that attenuated over time, while eGFR declined progressively over 104 weeks with glimepiride; the incidence of renal-related AEs with canagliflozin was generally stable over time, while the incidence with glimepiride increased over 104 weeks. In the analysis reported in this manuscript based on postmarketing reports from the US Food and Drug Administration Adverse Event Reporting System, a potential signal was identified for acute kidney injury with all approved sodium glucose co-transporter 2 (SGLT2) inhibitors (ie, canagliflozin, dapagliflozin, empagliflozin). The early onset of acute kidney injury events with SGLT2 inhibitors in postmarketing reports likely reflects the acute changes in eGFR due to the known renal haemodynamic effects of SGLT2 inhibition.

  3. Long-term aldosterone administration increases renal Na+-Cl- cotransporter abundance in late distal convoluted tubule

    DEFF Research Database (Denmark)

    Poulsen, Søren Brandt; Christensen, Birgitte M

    2016-01-01

    Renal Na+-Cl- cotransporter (NCC) is expressed in early distal convoluted tubule (DCT) 1 and late DCT (DCT2). NCC activity can be stimulated by aldosterone, and the mechanism is assumed to depend on the enzyme, 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which inactivates glucocorticoids...... that would otherwise occupy aldosterone receptors. Because 11β-HSD2 in rat may only be abundantly expressed in DCT2 cells and not in DCT1 cells, it has been speculated that aldosterone specifically stimulates NCC activity in DCT2 cells. In mice, however, it is debated if 11β-HSD2 is expressed in DCT2 cells....... The present study examined whether aldosterone-administration in mice stimulates NCC abundance and phosphorylation in DCT2 cells but not in DCT1 cells. B6/C57 male mice were administered 100 µg aldosterone (kg body weight)-1 (24 h)-1 for 6 days and euthanized during isoflurane inhalation. Western blotting...

  4. Double knockout of pendrin and Na-Cl cotransporter (NCC) causes severe salt wasting, volume depletion, and renal failure.

    Science.gov (United States)

    Soleimani, Manoocher; Barone, Sharon; Xu, Jie; Shull, Gary E; Siddiqui, Faraz; Zahedi, Kamyar; Amlal, Hassane

    2012-08-14

    The Na-Cl cotransporter (NCC), which is the target of inhibition by thiazides, is located in close proximity to the chloride-absorbing transporter pendrin in the kidney distal nephron. Single deletion of pendrin or NCC does not cause salt wasting or excessive diuresis under basal conditions, raising the possibility that these transporters are predominantly active during salt depletion or in response to excess aldosterone. We hypothesized that pendrin and NCC compensate for loss of function of the other under basal conditions, thereby masking the role that each plays in salt absorption. To test our hypothesis, we generated pendrin/NCC double knockout (KO) mice by crossing pendrin KO mice with NCC KO mice. Pendrin/NCC double KO mice displayed severe salt wasting and sharp increase in urine output under basal conditions. As a result, animals developed profound volume depletion, renal failure, and metabolic alkalosis without hypokalemia, which were all corrected with salt replacement. We propose that the combined inhibition of pendrin and NCC can provide a strong diuretic regimen without causing hypokalemia for patients with fluid overload, including patients with congestive heart failure, nephrotic syndrome, diuretic resistance, or generalized edema.

  5. Circadian exosomal expression of renal thiazide-sensitive NaCl cotransporter (NCC) and prostasin in healthy individuals.

    Science.gov (United States)

    Castagna, Annalisa; Pizzolo, Francesca; Chiecchi, Laura; Morandini, Francesca; Channavajjhala, Sarath Kiran; Guarini, Patrizia; Salvagno, Gianluca; Olivieri, Oliviero

    2015-06-01

    A circadian timing system is involved in the maintenance of fluid and electrolyte balance and blood pressure control. Aldosterone and vasopressin modulate ion transporters and channels crucial in sodium (Na) and water reabsorption such as the epithelium Na channel and the renal thiazide-sensitive NaCl cotransporter (NCC). We analyzed in urinary exosomes the intraday variations of NCC and prostasin expression and the association with electrolytes and water balance parameters. Blood and urine samples were collected at five time points during the day from five healthy subjects. Blood renin, aldosterone, cortisol, ACTH, and plasmatic and urinary Na, potassium, creatinine, adiuretin (ADH), NCC, and prostasin were evaluated. ACTH and cortisol showed a circadian pattern, similarly to aldosterone, while exosomal NCC and prostasin pattern were similar to urinary ADH, decreased in the morning and subsequently increased in the afternoon and evening. In urinary exosomes, NCC and prostasin had a diurnal pattern parallel to ADH and aquaporin 2, confirming that, in healthy subjects, both prostasin and NCC relate to water balance. These results provide suggestions for a possible chronotherapeutic approach in patients treated with thiazides, diuretic drugs acting as specific inhibitors of NCC-mediated Na reabsorption. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. The K–Cl Cotransporter KCC3 as an Independent Prognostic Factor in Human Esophageal Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Atsushi Shiozaki

    2014-01-01

    Full Text Available The objectives of the present study were to investigate the role of K–Cl cotransporter 3 (KCC3 in the regulation of cellular invasion and the clinicopathological significance of its expression in esophageal squamous cell carcinoma (ESCC. Immunohistochemical analysis performed on 70 primary tumor samples obtained from ESCC patients showed that KCC3 was primarily found in the cytoplasm of carcinoma cells. Although the expression of KCC3 in the main tumor (MT was related to several clinicopathological features, such as the pT and pN categories, it had no prognostic impact. KCC3 expression scores were compared between the MT and cancer nest (CN, and the survival rate of patients with a CN>MT score was lower than that of patients with a CN≤MT score. In addition, the survival rate of patients in whom KCC3 was expressed in the invasive front of tumor was lower than that of the patients without it. Furthermore, multivariate analysis demonstrated that the expression of KCC3 in the invasive front was one of the most important independent prognostic factors. The depletion of KCC3 using siRNAs inhibited cell migration and invasion in human ESCC cell lines. These results suggest that the expression of KCC3 in ESCC may affect cellular invasion and be related to a worse prognosis in patients with ESCC.

  7. Sodium-glucose co-transporter-2 inhibitors as add-on therapy to insulin: rationale and evidences.

    Science.gov (United States)

    Singh, Awadhesh Kumar; Singh, Ritu

    2016-01-01

    Sodium-glucose co-transporter-2 inhibitors (SGLT-2I) are recently approved class of anti-hyperglycaemic agents for the treatment of type 2 diabetes mellitus (T2DM). SGLT-2I inhibits renal glucose reabsorption, thereby ensuing urinary glucose excretion in a dose-dependent manner. This caloric loss and osmotic diuresis, secondary to increased urinary glucose excretion, has a unique potential to counter insulin induced weight gain and fluid retention, with little potential of hypoglycemic exacerbation. Also, as these agents act independently of insulin secretion or action, they are effective even in long-standing diabetes with depleted β-cell reserve. Improvement in insulin sensitivity, as observed with SGLT-2I can also facilitate insulin action. Furthermore, significant reduction in total daily insulin dosage and reduction of body weight as observed during combination therapy renders SGLT-2I, a near-ideal partner to insulin. This review aims to evaluate the safety and efficacy of currently used SGLT-2I as an add-on to insulin therapy in the treatment of T2DM.

  8. Swine Influenza/Variant Influenza Viruses

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Influenza Types Seasonal Avian Swine Variant Other Information on Swine Influenza/Variant Influenza Virus Language: English (US) Español ...

  9. Resistance of Abaca Somaclonal Variant Against Fusarium

    OpenAIRE

    RULLY DYAH PURWATI; SUDARSONO

    2007-01-01

    The objectives of this study were (i) to evaluate responses against F. oxysporum f.sp. cubense (Foc) infection of abaca variants regenerated using four different methods, (ii) to determine initial root length and plant height effects on survival of inoculated abaca variants, and (iii) to identify Foc resistance abaca variants. In the previous experiment, four abaca variant lines were regenerated from (i) embryogenic calli (TC line), (ii) ethyl methyl sulphonate (EMS) treated embryogenic calli...

  10. Variant Humicola grisea CBH1.1

    Energy Technology Data Exchange (ETDEWEB)

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2017-05-09

    Disclosed are variants of Humicola grisea CeI7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  11. DHAD variants and methods of screening

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Kristen J.; Ye, Rick W.

    2017-02-28

    Methods of screening for dihydroxy-acid dehydratase (DHAD) variants that display increased DHAD activity are disclosed, along with DHAD variants identified by these methods. Such enzymes can result in increased production of compounds from DHAD requiring biosynthetic pathways. Also disclosed are isolated nucleic acids encoding the DHAD variants, recombinant host cells comprising the isolated nucleic acid molecules, and methods of producing butanol.

  12. Clinical variants of lichen planus.

    Science.gov (United States)

    Wagner, Gunnar; Rose, Christian; Sachse, Michael Max

    2013-04-01

    Lichen planus is characterized by lichenoid, polygonal papules with fine white lines, called Wickham striae. Lesions most commonly occur on the limbs and on the dorsal aspect of the trunk. At the same time often leukoplakia of mucous membranes as well as nail disorders are seen. There are numerous variants of lichen planus which can be distinguished from the classical form on the basis of morphology and distribution of the lesions. The typical primary lesion of lichen planus may be replaced by other forms, such as patches, hyperkeratoses, ulcerations, or bullous lesions. Moreover, distribution patterns of these lesions may vary and include erythrodermic, inverse or linear arrangements. In contrast to these numerous clinical features, histologic findings remain characteristic in the variants, so that the diagnosis can be made securely. Differential diagnoses of lichen planus include diverse dermatoses such as bullous pemphigoid or paronychia.

  13. Coronary artery anatomy and variants

    Energy Technology Data Exchange (ETDEWEB)

    Malago, Roberto; Pezzato, Andrea; Barbiani, Camilla; Alfonsi, Ugolino; Nicoli, Lisa; Caliari, Giuliana; Pozzi Mucelli, Roberto [Policlinico G.B. Rossi, University of Verona, Department of Radiology, Verona (Italy)

    2011-12-15

    Variants and congenital anomalies of the coronary arteries are usually asymptomatic, but may present with severe chest pain or cardiac arrest. The introduction of multidetector CT coronary angiography (MDCT-CA) allows the detection of significant coronary artery stenosis. Improved performance with isotropic spatial resolution and higher temporal resolution provides a valid alternative to conventional coronary angiography (CCA) in many patients. MDCT-CA is now considered the ideal tool for three-dimensional visualization of the complex and tortuous anatomy of the coronary arteries. With multiplanar and volume-rendered reconstructions, MDCT-CA may even outperform CCA in determining the relative position of vessels, thus providing a better view of the coronary vascular anatomy. The purpose of this review is to describe the normal anatomy of the coronary arteries and their main variants based on MDCT-CA with appropriate reconstructions. (orig.)

  14. [Mirizzi syndrome and its variants].

    Science.gov (United States)

    Meyer, G J; Runge, D; Gebhardt, J

    1990-04-01

    Between 1981 and 1987 5434 patients were studied by ERCP in Allgemeines Krankenhaus Hamburg-Barmbeck. 26 (i.e. 0.43%) suffered from Mirizze syndrome with the triad of cholelithiasis, cholecystitis and obstructive biliary disease. They were classified in four different types according to the variable localisation and origin of the biliary obstruction. 16 patients corresponded to the classical type (I and II) with compression, penetration, and obturation by the concrement, five patients matched borderline with infiltration (III) and five patients were classified as variants of this syndrome. A mild elevation of serum bilirubine and alkaline phosphatase indicated more likely the benign etiology of type I to III, however, a marked elevation of alkaline phosphatase in the variants suggested more likely a malignant underlying disease. The diagnosis was ascertained in all cases by ERC and sonography preoperatively and was verified by laparotomy (n = 18) and follow-up (n = 6).

  15. Variants of lumbosacral elastic band.

    Directory of Open Access Journals (Sweden)

    Carlos Cesar Santín Alfaro

    2011-06-01

    Full Text Available It is made an intervention research, qualitative and quantitative of two variants of lumbosacral elastic bands used in Provincial Laboratory of Technical Orthopedics in Sancti Spiritus Province, taking into account the high demand for this device and that the laboratory do not often count with the raw material needed for the original lumbosacral belt made by denim cloth which is the conventional belt. The main goal of this research is to explain the technological process and to compare the cost of production of both elastic variants with lumbosacral belt made by cloth which are offer to patients who look for this service , giving them a rapid solution so that they can feel comfortable.

  16. Unusual variant of Cantrell's pentalogy?

    OpenAIRE

    Kumar, Basant; Sharma, S.B.; Kandpal, Deepak K.; Agrawal, L. D.

    2008-01-01

    A 12-hour-old male infant presented with prolapsed abdominal content through a defect on left side of chest wall with respiratory distress. A thorough clinical examination suggested absence of ectopia cordis, abdominal wall defect, and any bony anomaly. The child expired after 6 hours of admission because of respiratory distress and electrolyte imbalance. Is congenital defect of chest wall associated with diaphragmatic hernia without ectopia cordis and omphalocele, an unusual variant of Cantr...

  17. Dorsal variant blister aneurysm repair.

    Science.gov (United States)

    Couldwell, William T; Chamoun, Roukoz

    2012-01-01

    Dorsal variant proximal carotid blister aneurysms are treacherous lesions to manage. It is important to recognize this variant on preoperative angiographic imaging, in anticipation of surgical strategies for their treatment. Strategies include trapping the involved segment and revascularization if necessary. Other options include repair of the aneurysm rupture site directly. Given that these are not true berry aneurysms, repair of the rupture site involves wrapping or clip-grafting techniques. The case presented here was a young woman with a subarachnoid hemorrhage from a ruptured dorsal variant blister aneurysm. The technique used is demonstrated in the video and is a modified clip-wrap technique using woven polyester graft material. The patient was given aspirin preoperatively as preparation for the clip-wrap technique. It is the authors' current protocol to attempt a direct repair with clip-wrapping and leaving artery sacrifice with or without bypass as a salvage therapy if direct repair is not possible. Assessment of vessel patency after repair is performed by intraoperative Doppler and indocyanine green angiography. Intraoperative somatosensory and motor evoked potential monitoring is performed in all cases. The video can be found here: http://youtu.be/crUreWGQdGo.

  18. Microcystic Variant of Urothelial Carcinoma

    Directory of Open Access Journals (Sweden)

    Anthony Kodzo-Grey Venyo

    2013-01-01

    Full Text Available Background. Microcystic variant of urothelial carcinoma is one of the new variants of urothelial carcinoma that was added to the WHO classification in 2004. Aims. To review the literature on microcystic variant of urothelial carcinoma. Methods. Various internet search engines were used to identify reported cases of the tumour. Results. Microscopic features of the tumour include: (i Conspicuous intracellular and intercellular lumina/microcysts encompassed by malignant urothelial or squamous cells. (ii The lumina are usually empty; may contain granular eosinophilic debris, mucin, or necrotic cells. (iii The cysts may be variable in size; round, or oval, up to 2 mm; lined by urothelium which are either flattened cells or low columnar cells however, they do not contain colonic epithelium or goblet cells; are infiltrative; invade the muscularis propria; mimic cystitis cystica and cystitis glandularis; occasionally exhibit neuroendocrine differentiation. (iv Elongated and irregular branching spaces are usually seen. About 17 cases of the tumour have been reported with only 2 patients who have survived. The tumour tends to be of high-grade and high-stage. There is no consensus opinion on the best option of treatment of the tumour. Conclusions. It would prove difficult at the moment to be dogmatic regarding its prognosis but it is a highly aggressive tumour. New cases of the tumour should be reported in order to document its biological behaviour.

  19. Empagliflozin: a new sodium-glucose co-transporter 2 (SGLT2 inhibitor for the treatment of type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Joshua J Neumiller

    2014-06-01

    Full Text Available Type 2 diabetes is increasing in prevalence worldwide, and hyperglycemia is often poorly controlled despite a number of therapeutic options. Unlike previously available agents, sodium-glucose co-transporter 2 (SGLT2 inhibitors offer an insulin-independent mechanism for improving blood glucose levels, since they promote urinary glucose excretion (UGE by inhibiting glucose reabsorption in the kidney. In addition to glucose control, SGLT2 inhibitors are associated with weight loss and blood pressure reductions, and do not increase the risk of hypoglycemia. Empagliflozin is a selective inhibitor of SGLT2, providing dose-dependent UGE increases in healthy volunteers, with up to 90 g of glucose excreted per day. It can be administered orally, and studies of people with renal or hepatic impairment indicated empagliflozin needed no dose adjustment based on pharmacokinetics. In Phase II trials in patients with type 2 diabetes, empagliflozin provided improvements in glycosylated hemoglobin (HbA1c and other measures of glycemic control when given as monotherapy or add-on to metformin, as well as reductions in weight and systolic blood pressure. As add-on to basal insulin, empagliflozin not only improved HbA1c levels but also reduced insulin doses. Across studies, empagliflozin was generally well tolerated with a similar rate of hypoglycemia to placebo; however, patients had a slightly increased frequency of genital infections, but not urinary tract infections, versus placebo. Phase III studies have also reported a good safety profile along with significant improvements in HbA1c, weight and blood pressure, with no increased risk of hypoglycemia versus placebo. Based on available data, it appears that empagliflozin may be a useful option in a range of patients; however, clinical decisions will be better informed by the results of ongoing studies, in particular, a large cardiovascular outcome study (EMPA-REG OUTCOME™.

  20. Interaction of human organic anion transporter 2 (OAT2) and sodium taurocholate cotransporting polypeptide (NTCP) with antineoplastic drugs.

    Science.gov (United States)

    Marada, Venkata V V R; Flörl, Saskia; Kühne, Annett; Müller, Judith; Burckhardt, Gerhard; Hagos, Yohannes

    2015-01-01

    The ability of an antineoplastic drug to exert its cytostatic effect depends largely on the balance between its uptake into and extrusion from the cancer cells. ATP driven efflux transporter proteins drive the export of antineoplastic drugs and play a pivotal role in the development of chemoresistance. As regards uptake transporters, comparably less is known on their impact in drug action. In the current study, we characterized the interactions of two uptake transporter proteins, expressed mainly in the liver; the organic anion transporter 2 (OAT2, encoded by the SLC22A7 gene) and the sodium taurocholate cotransporting polypeptide (NTCP, encoded by the SLC10A1 gene), stably transfected in human embryonic kidney cells, with some antineoplastic agents that are routinely being used in cancer chemotherapy. Whereas NTCP did not show any strong interactions with the cytostatics tested, we observed a very strong inhibition of OAT2 mediated [(3)H] cGMP uptake in the presence of bendamustine, irinotecan and paclitaxel. The Ki values of OAT2 for bendamustine, irinotecan and paclitaxel were determined to be 43.3±4.33μM, 26.4±2.34μM and 10.4±0.45μM, respectively. Incubation of bendamustine with OAT2 expressing cells increased the caspase-3 activity, and this increase was inhibited by simultaneous incubation with bendamustine and probenecid, a well-known inhibitor of OATs, suggesting that bendamustine is a substrate of OAT2. A higher accumulation of irinotecan was observed in OAT2 expressing cells compared to control pcDNA cells by HPLC analysis of cell lysates. The accumulation was diminished in the presence of cGMP, the substrate we used to functionally characterize OAT2, suggesting specificity of this uptake and the fact that OAT2 mediates uptake of irinotecan. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Safety of Sodium-Glucose Co-Transporter 2 Inhibitors during Ramadan Fasting: Evidence, Perceptions and Guidelines

    Directory of Open Access Journals (Sweden)

    Salem A. Beshyah

    2016-06-01

    Full Text Available Sodium-glucose co-transporter 2 (SGLT2 inhibitors are a new glucose-lowering therapy for T2DM with documented benefits on blood glucose, hypertension, weight reduction and long term cardiovascular benefit. They have an inherent osmotic diuretic effect and lead to some volume loss and possible dehydration. There is some concern about the safety of using SGLT2 inhibitors in Muslim type 2 diabetes mellitus (T2DM patients during the fast during Ramadan. Currently, there is a dearth of research data to help guide physicians and reassure patients.  One study confirmed good glycemic control with less risk of hypoglycemia and no marked volume depletion. Data in the elderly and in combination with diuretics are reassuring of their safe to use in Ramadan in general. SGLT2 inhibitor-related diabetic ketoacidosis has not been reported during Ramadan and is unlikely to be relevant. Survey of physicians revealed that the majority felt that SGLT2 inhibitors are generally safe in T2DM patients during Ramadan fasting but should be discontinued in certain high risk patients. Some professional groups with interest in diabetes and Ramadan fasting included SGLT2 inhibitors in their guidelines on management of diabetes during Ramadan. They acknowledged the lack of trial data, recommended caution in high risk groups, advised regular monitoring and emphasized pre-Ramadan patients’ education. In conclusion, currently, knowledge, data and experience with SGLT2 inhibitors in Ramadan are limited. Nonetheless, stable patients with normal kidney function and low risk of dehydration may safely use the SGLT2 inhibitors therapy. Higher risk patients should be observed carefully and managed on individual basis.

  2. Interaction of the Sodium/Glucose Cotransporter (SGLT) 2 inhibitor Canagliflozin with SGLT1 and SGLT2.

    Science.gov (United States)

    Ohgaki, Ryuichi; Wei, Ling; Yamada, Kazunori; Hara, Taiki; Kuriyama, Chiaki; Okuda, Suguru; Ueta, Kiichiro; Shiotani, Masaharu; Nagamori, Shushi; Kanai, Yoshikatsu

    2016-07-01

    Canagliflozin, a selective sodium/glucose cotransporter (SGLT) 2 inhibitor, suppresses the renal reabsorption of glucose and decreases blood glucose level in patients with type 2 diabetes. A characteristic of canagliflozin is its modest SGLT1 inhibitory action in the intestine at clinical dosage. To reveal its mechanism of action, we investigated the interaction of canagliflozin with SGLT1 and SGLT2. Inhibition kinetics and transporter-mediated uptake were examined in human SGLT1- or SGLT2-expressing cells. Whole-cell patch-clamp recording was conducted to examine the sidedness of drug action. Canagliflozin competitively inhibited SGLT1 and SGLT2, with high potency and selectivity for SGLT2. Inhibition constant (Ki) values for SGLT1 and SGLT2 were 770.5 and 4.0 nM, respectively. (14)C-canagliflozin was suggested to be transported by SGLT2; however, the transport rate was less than that of α-methyl-d-glucopyranoside. Canagliflozin inhibited α-methyl-d-glucopyranoside-induced SGLT1- and SGLT2-mediated inward currents preferentially from the extracellular side and not from the intracellular side. Based on the Ki value, canagliflozin is estimated to sufficiently inhibit SGLT2 from the urinary side in renal proximal tubules. The Ki value for SGLT1 suggests that canagliflozin suppresses SGLT1 in the small intestine from the luminal side, whereas it does not affect SGLT1 in the heart and skeletal muscle, considering the maximal concentration of plasma-unbound canagliflozin. Similarly, SGLT1 in the kidney would not be inhibited, thereby aiding in the prevention of hypoglycemia. After binding to SGLT2, canagliflozin may be reabsorbed by SGLT2, which leads to the low urinary excretion and prolonged drug action of canagliflozin. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Effect of hepatic or renal impairment on the pharmacokinetics of canagliflozin, a sodium glucose co-transporter 2 inhibitor.

    Science.gov (United States)

    Devineni, Damayanthi; Curtin, Christopher R; Marbury, Thomas C; Smith, William; Vaccaro, Nicole; Wexler, David; Vandebosch, An; Rusch, Sarah; Stieltjes, Hans; Wajs, Ewa

    2015-03-01

    Canagliflozin is a sodium-glucose cotransporter 2 inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM). Because T2DM is often associated with renal or hepatic impairment, understanding the effects of these comorbid conditions on the pharmacokinetics of canagliflozin, and further assessing its safety, in these special populations is essential. Two open-label studies evaluated the pharmacokinetics, pharmacodynamics (renal study only), and safety of canagliflozin in participants with hepatic or renal impairment. Participants in the hepatic study (8 in each group) were categorized based on their Child-Pugh score (normal hepatic function, mild impairment [Child-Pugh score of 5 or 6], and moderate impairment [Child-Pugh score of 7-9]) and received a single oral dose of canagliflozin 300 mg. Participants in the renal study (8 in each group) were categorized based on their creatinine clearance (CLCR) (normal renal function [CLCR ≥80 mL/min]; mild [CLCR 50 to canagliflozin 200 mg; the exception was those with ESRD, who received 1 dose postdialysis and 1 dose predialysis (10 days later). Canagliflozin's pharmacokinetics and pharmacodynamics (urinary glucose excretion [UGE] and renal threshold for glucose excretion [RTG]) were assessed at predetermined time points. Mean maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to infinite (AUC)0-∞ values differed by Canagliflozin's pharmacokinetics were not affected by mild or moderate hepatic impairment. Systemic exposure to canagliflozin increased in the renal impairment groups relative to participants with normal renal function. Pharmacodynamic response to canagliflozin, measured by using UGE and RTG, declined with increasing severity of renal impairment. A single oral dose of canagliflozin was well tolerated by participants in both studies. ClinicalTrials.gov identifiers: NCT01186588 and NCT01759576. Copyright © 2015 Elsevier HS Journals, Inc. All rights

  4. Intestinal Sodium Glucose Cotransporter 1 Inhibition Enhances Glucagon-Like Peptide-1 Secretion in Normal and Diabetic Rodents.

    Science.gov (United States)

    Oguma, Takahiro; Nakayama, Keiko; Kuriyama, Chiaki; Matsushita, Yasuaki; Yoshida, Kumiko; Hikida, Kumiko; Obokata, Naoyuki; Tsuda-Tsukimoto, Minoru; Saito, Akira; Arakawa, Kenji; Ueta, Kiichiro; Shiotani, Masaharu

    2015-09-01

    The sodium glucose cotransporter (SGLT) 1 plays a major role in glucose absorption and incretin hormone release in the gastrointestinal tract; however, the impact of SGLT1 inhibition on plasma glucagon-like peptide-1 (GLP-1) levels in vivo is controversial. We analyzed the effects of SGLT1 inhibitors on GLP-1 secretion in normoglycemic and hyperglycemic rodents using phloridzin, CGMI [3-(4-cyclopropylphenylmethyl)-1-(β-d-glucopyranosyl)-4-methylindole], and canagliflozin. These compounds are SGLT2 inhibitors with moderate SGLT1 inhibitory activity, and their IC50 values against rat SGLT1 and mouse SGLT1 were 609 and 760 nM for phloridzin, 39.4 and 41.5 nM for CGMI, and 555 and 613 nM for canagliflozin, respectively. Oral administration of these inhibitors markedly enhanced and prolonged the glucose-induced plasma active GLP-1 (aGLP-1) increase in combination treatment with sitagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, in normoglycemic mice and rats. CGMI, the most potent SGLT1 inhibitor among them, enhanced glucose-induced, but not fat-induced, plasma aGLP-1 increase at a lower dose compared with canagliflozin. Both CGMI and canagliflozin delayed intestinal glucose absorption after oral administration in normoglycemic rats. The combined treatment of canagliflozin and a DPP4 inhibitor increased plasma aGLP-1 levels and improved glucose tolerance compared with single treatment in both 8- and 13-week-old Zucker diabetic fatty rats. These results suggest that transient inhibition of intestinal SGLT1 promotes GLP-1 secretion by delaying glucose absorption and that concomitant inhibition of intestinal SGLT1 and DPP4 is a novel therapeutic option for glycemic control in type 2 diabetes mellitus. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  5. Genistein affects parathyroid gland and NaPi 2a cotransporter in an animal model of the andropause.

    Science.gov (United States)

    Pantelic, J; Ajdzanovic, V; Medigovic, I; Mojic, M; Trifunovic, S; Milosevic, V; Filipovic, B

    2013-06-01

    This study aimed to examine the effects of genistein on the structural and functional changes in parathyroid glands (PTG) and sodium phosphate cotransporter 2a (NaPi 2a) in orchidectomized rats. Sixteen-month-old Wistar rats were divided into sham-operated (SO), orchidectomized (Orx) and genistein-treated orchidectomized (Orx+G) groups. Genistein (30 mg/kg/day) was administered subcutaneously for 3 weeks, while the controls received vehicle alone. PTG was analyzed histomorphometrically, while the expressions of NaPi 2a mRNA/protein levels from kidneys were determined by real time PCR and Western blots. Serum and urine parameters were determined biochemically. The PTG volume in Orx rats was increased by 30% (p<0.05), compared to the SO group. Orx+G treatment increased the PTG volume by 35% and 75% (p<0.05) respectively, comparing to Orx and SO animals. Orchidectomy led to increment of serum PTH by 27% (p<0.05) compared to the SO group, Orx+G decreased it by 18% (p<0.05) comparing to Orx animals. NaPi 2a expression in Orx animals was reduced in regards to its abundance in SO animals, although it was increased in Orx+G group compared to the Orx. Phosphorus urine content of Orx animals was raised by 12% (p<0.05) compared to that for the SO group, while Orx+G induced a 17% reduction (p<0.05) in regards to Orx animals. Our study shows that Orx increases PTG volume and serum PTH level, while protein expression of NaPi 2a is reduced. Application of genistein attenuates the orchidectomy-induced changes in serum PTH level, stimulates the expression of NaPi 2a and reduces urinary Pi excretion, implying potential beneficial effects on andropausal symptoms.

  6. Subjects heterozygous for genetic loss of function of the thiazide-sensitive cotransporter have reduced blood pressure.

    Science.gov (United States)

    Fava, C; Montagnana, M; Rosberg, L; Burri, P; Almgren, P; Jönsson, A; Wanby, P; Lippi, G; Minuz, P; Hulthèn, L U; Aurell, M; Melander, O

    2008-02-01

    Gitelmańs syndrome (GS) is an inherited recessive disorder caused by homozygous or compound heterozygous loss of function mutations of the NaCl cotransporter (NCCT) gene encoding the kidney-expressed NCCT, the pharmacological target of thiazide diuretics. An observational study estimated the prevalence of GS to 19/1,000,000, in Sweden, suggesting that approximately 1% of the population carries one mutant NCCT allele. As the phenotype of GS patients, who always carry two mutant alleles, is indistinguishable from that seen in patients treated with high-dose thiazide diuretics, we aimed at investigating whether subjects carrying one mutated NCCT allele have a phenotype resembling that of treatment with low-dose thiazide diuretics. We screened first-degree relatives of 18 of our patients with an established clinical end genetic diagnosis of GS for NCCT loss of function mutations and identified 35 healthy subjects carrying one mutant allele (GS-heterozygotes). Each GS-heterozygote was assigned a healthy control subject matched for age, BMI and sex. GS-heterozygotes had markedly lower blood pressure (systolic 103.3 +/- 16.4 versus 123.2 +/- 19.4 mmHg; diastolic 62.5 +/- 10.5 versus 73.1 +/- 9.4 mmHg; P pressure and slightly higher fasting plasma glucose compared with control subjects. Our findings suggest that GS-heterozygotes, the prevalence of which can be estimated to 1%, are partially protected from hypertension through partial genetic loss of function of the NCCT. However, as our study had a case-control design, it is important to underline that any potential effects on population blood pressure and risk of future cardiovascular disease need to be examined in prospective and population-based studies.

  7. Inhibition of Sodium-GlucoseCotransporter 2 with Dapagliflozin in Han: SPRD Rats with Polycystic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Daniel Rodriguez

    2015-12-01

    Full Text Available Background/Aims: Dapagliflozin (DAPA is a selective inhibitor of the sodium-glucose cotransporter 2 (SGLT2 which induces glucosuria and osmotic diuresis. The therapeutic effect of DAPA in progressing stages of polycystic kidney disease (PKD has not been studied. Methods: We examined the effect of DAPA in the Han: SPRD rat model of PKD. DAPA (10 mg/kg/day or vehicle (VEH was administered orally via gavage to 5 week old male Han: SPRD (Cy/+ or control (+/+ rats (n = 8-9 per group for 5 weeks. Blood and urine were collected at baseline and after 2.5 and 5 weeks of treatment to assess renal function and albuminuria. At the end of the treatment, rats were sacrificed and kidneys were excised for histological analysis. Results: After 5 weeks of treatment, DAPA-treated Cy/+ and +/+ rats exhibited significantly higher glucosuria, water intake and urine output than VEH-treated rats. DAPA-treated Cy/+ rats also exhibited significantly higher clearances for creatinine and BUN and less albuminuria than VEH-treated Cy/+ rats. DAPA treatment for 5 weeks resulted in a significant increase of the kidney weight in Cy/+ rats but no change in cyst growth. The degree of tubular epithelial cell proliferation, macrophage infiltration and interstitial fibrosis was also similar in DAPA-and VEH-treated Cy/+ rats. Conclusion: The induction of glucosuria with the SGLT2-specific inhibitor DAPA was associated with improved renal function and decreased albuminuria, but had no effect on cyst growth in Cy/+ rats. Overall the beneficial effects of DAPA in this PKD model were weaker than the previously described effects of the combined SGLT1/2 inhibitor phlorizin.

  8. Use of sodium-glucose cotransporter 2 inhibitors in older patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Kambara, Takahiro; Shibata, Rei; Osanai, Hiroyuki; Nakashima, Yoshihito; Asano, Hiroshi; Sakai, Kazuyoshi; Murohara, Toyoaki; Ajioka, Masayoshi

    2017-09-01

    Sodium-glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic agents that act on the proximal renal tubules to lower blood glucose levels by inhibiting glucose reabsorption and promoting urinary glucose excretion. The present study assessed the long-term use of SGLT2 inhibitors in older patients with diabetes. A total of 117 older patients with type 2 diabetes who were given SGLT2 inhibitors were enrolled from April 2014 to March 2016. The mean age of the patients was 73.7 ± 10.0 years. During the follow-up period (mean 289.3 days), there was no event associated with oral administration of SGLT2 inhibitors. These drugs significantly lowered fasting blood glucose and glycosylated hemoglobin levels at 6 months, and did not affect the creatinine level, blood urea nitrogen/creatinine ratio or estimated glomerular filtration rate during treatment. Although the treatment significantly increased hemoglobin and hematocrit levels, it did not affect the ultrasonographically determined diameter of the inferior vena cava, and no signs of intravascular collapse were observed. Changes in brain natriuretic peptide levels during the follow-up period were assessed in 78 patients with a brain natriuretic peptide level exceeding the normal upper limit before treatment with SGLT2 inhibitors. The brain natriuretic peptide levels significantly decreased after 6 months of treatment. In older Japanese patients with diabetes, treatment with SGLT2 inhibitors for 6 months exerted a favorable hypoglycemic effect, while no sign of dehydration was observed. Geriatr Gerontol Int 2017; ••: ••-••. © 2017 Japan Geriatrics Society.

  9. Thiazide diuretics directly induce osteoblast differentiation and mineralized nodule formation by targeting a NaCl cotransporter in bone

    Science.gov (United States)

    Dvorak, Melita M; De Joussineau, Cyrille; Carter, D Howard; Pisitkun, Trairak; Knepper, Mark A; Gamba, Gerardo; Kemp, Paul J; Riccardi, Daniela

    2008-01-01

    Thiazide diuretics are used, worldwide, as the first-choice drug for patients with uncomplicated hypertension. In addition to their anti-hypertensive actions, they increase bone mineral density and reduce the prevalence of fractures, indicating that thiazides may have a role in the management of postmenopausal osteoporosis. Traditionally, the bone-protective effects of thiazides have been attributed to an increase in renal calcium reabsorption, secondary to the inhibition of the sodium chloride cotransporter, NCC, expressed in the kidney distal tubule. Whether thiazides exert a direct osteoanabolic effect independently of their renal action is controversial. Here we demonstrate that freshly frozen sections of human and rat bone express NCC, principally in bone-forming cells, the osteoblasts. In primary and established culture models of osteoblasts, fetal rat calvarial (FRC) and human MG63 cells, NCC protein is virtually absent in proliferating cells while its expression is dramatically increased during differentiation. Thiazides directly stimulate the production of osteoblast markers, runt-related transcription factor 2 (runx2) and osteopontin, in the absence of a proliferative effect. Using overexpression/knockdown studies in FRC cells, we show that thiazides, but not loop diuretics, increase mineralized nodule formation acting on NCC. Overall, our study demonstrates that thiazides stimulate osteoblast differentiation and bone mineral formation independently of their renal actions. In addition to their use as part of a therapeutic treatment plan for elderly, hypertensive individuals, our discovery opens up the possibility that bone-specific drug targeting by thiazides may be developed for the prevention and treatment of osteoporosis in the patient population as a whole. PMID:17656470

  10. The KCl cotransporter, KCC2, is highly expressed in the vicinity of excitatory synapses in the rat hippocampus.

    Science.gov (United States)

    Gulyás, A I; Sík, A; Payne, J A; Kaila, K; Freund, T F

    2001-06-01

    Immunocytochemical visualization of the neuron-specific K+/Cl- cotransporter, KCC2, at the cellular and subcellular level revealed an area- and layer-specific diffuse labelling, and a discrete staining outlining the somata and dendrites of some interneurons in all areas of the rat hippocampus. KCC2 was highly expressed in parvalbumin-containing interneurons, as well as in subsets of calbindin, calretinin and metabotropic glutamate receptor 1a-immunoreactive interneurons. During the first 2 postnatal weeks, an increase of KCC2 staining was observed in the molecular layer of the dentate gyrus, correlating temporally with the arrival of entorhinal cortical inputs. Subcellular localization demonstrated KCC2 in the plasma membranes. Immunoreactivity in principal cells was responsible for the diffuse staining found in the neuropil. In these cells, KCC2 was detected primarily in dendritic spine heads, at the origin of spines and, at a much lower level on the somata and dendritic shafts. KCC2 expression was considerably higher in the somata and dendrites of interneurons, most notably of parvalbumin-containing cells, as well as in the thorny excrescences of CA3 pyramidal cells and in the spines of spiny hilar and stratum lucidum interneurons. The data indicate that KCC2 is highly expressed in the vicinity of excitatory inputs in the hippocampus, perhaps in close association with extrasynaptic GABAA receptors. A high level of excitation is known to lead to a simultaneous net influx of Na+ and Cl-, as evidenced by dendritic swelling. KCC2 located in the same microenvironment may provide a Cl- extrusion mechanism to deal with both ion and water homeostasis in addition to its role in setting the driving force of Cl- currents involved in fast postsynaptic inhibition.

  11. 钠-葡萄糖协同转运蛋白与糖尿病%Sodium-glucose cotransporters and diabetes

    Institute of Scientific and Technical Information of China (English)

    朱蕾; 杨怡

    2011-01-01

    Sodium-glucose cotransporters (SGLTs) are carrier proteins which can help glucose to enter eukaryotic cells.Among them,the SGLT1 and SGLT2 are the most important ones and play major roles in dietary glucose absorption and renal glucose reabsorption respectively.In the state of diabetes,increased expression of SGLT1 in the intestine will enhance the glucose absorption and therefore accelerate hyperglycemia.Through decreasing salivary secretion,increased expression of SGLT1 in salivary glands will promote the development of diabetic oral complications.Meanwhile the expression of SGLT1 and SGLT2 in kidney are also increased which will enhance the glucose reabsorption and therefore accelerate hyperglycemia and deteriorate dial.tic nephropathy.At present,selective inhibitor of SGLT2 is becoming a new drug for diabetes.%钠-葡萄糖协同转运蛋白(SGLTs)在葡萄糖的跨细胞转运中发挥重要作用,其中SGLT1负责膳食葡萄糖的吸收,SGLT2负责肾脏中葡萄糖的重吸收.在糖尿病状态下,肠道SGLT1表达的增加将促进葡萄糖的吸收,从而加重了高血糖,而涎腺导管SGLT1表达的增加则使唾液分泌减少,促进了口腔并发症的发生;肾脏SGLT2和SGLT1表达的增加使葡萄糖的重吸收增加,加重了高血糖,并促进了糖尿病肾病的进展.目前,选择性SLGT2抑制剂已经成为新型的抗糖尿病药物.

  12. Prenatal hypoxia-ischemia induces abnormalities in CA3 microstructure, potassium chloride cotransporter 2 expression and inhibitory tone

    Directory of Open Access Journals (Sweden)

    Lauren L Jantzie

    2015-09-01

    Full Text Available Infants who suffer perinatal brain injury, including those with encephalopathy of prematurity, are prone to chronic neurological deficits including epilepsy, cognitive impairment, and behavioral problems such as anxiety, inattention and poor social interaction. These deficits, especially in combination, pose the greatest hindrance to these children becoming independent adults. Cerebral function depends on adequate development of essential inhibitory neural circuits and the appropriate amount of excitation and inhibition at specific stages of maturation. Early neuronal synaptic responses to γ-amino butyric acid (GABA are initially excitatory. During the early postnatal period, GABAAR responses switch to inhibitory with the upregulation of potassium-chloride co-transporter KCC2. With extrusion of chloride by KCC2, the Cl- reversal potential shifts and GABA and glycine responses become inhibitory. We hypothesized that prenatal hypoxic-ischemic brain injury chronically impairs the developmental upregulation of KCC2 that is essential for cerebral circuit formation. Following late gestation hypoxia-ischemia, diffusion tensor imaging in juvenile rats shows poor microstructural integrity in the hippocampal CA3 subfield, with reduced fractional anisotropy and elevated radial diffusivity. The loss of microstructure correlates with early reduced KCC2 expression on NeuN-positive pyramidal neurons, and decreased monomeric and oligomeric KCC2 protein expression in the CA3 subfield. Together with decreased IPSCs during a critical window of development, we document for the first time that prenatal transient systemic hypoxia-ischemia in rats impairs hippocampal CA3 inhibitory tone. Failure of timely development of inhibitory tone likely contributes to a lower seizure threshold and impaired cognitive function in children who suffer perinatal brain injury.

  13. Double knockout of carbonic anhydrase II (CAII) and Na(+)-Cl(-) cotransporter (NCC) causes salt wasting and volume depletion.

    Science.gov (United States)

    Xu, Jie; Barone, Sharon; Brooks, Mary-Beth; Soleimani, Manoocher

    2013-01-01

    The thiazide-sensitive Na(+)-Cl(-) cotransporter NCC and the Cl(-)/HCO3(-)exchanger pendrin are expressed on apical membranes of distal cortical nephron segments and mediate salt absorption, with pendrin working in tandem with the epithelial Na(+) channel (ENaC) and the Na(+)-dependent chloride/bicarbonate exchanger (NDCBE), whereas NCC is working by itself. A recent study showed that NCC and pendrin compensate for loss of each other under basal conditions, therefore masking the role that each plays in salt reabsorption. Carbonic anhydrase II (CAII, CA2 or CAR2) plays an important role in acid-base transport and salt reabsorption in the proximal convoluted tubule and acid-base transport in the collecting duct. Animals with CAII deletion show remodeling of intercalated cells along with the downregulation of pendrin. NCC KO mice on the other hand show significant upregulation of pendrin and ENaC. Neither model shows any significant salt wasting under baseline conditions. We hypothesized that the up-regulation of pendrin is essential for the prevention of salt wasting in NCC KO mice. To test this hypothesis, we generated NCC/CAII double KO (dKO) mice by crossing mice with single deletion of NCC and CAII. The NCC/CAII dKO mice displayed significant downregulation of pendrin, along with polyuria and salt wasting. As a result, the dKO mice developed volume depletion, which was associated with the inability to concentrate urine. We conclude that the upregulation of pendrin is essential for the prevention of salt and water wasting in NCC deficient animals and its downregulation or inactivation will result in salt wasting, impaired water conservation and volume depletion in the setting of NCC inactivation or inhibition. © 2014 S. Karger AG, Basel.

  14. Acute hypertension provokes acute trafficking of distal tubule Na-Cl cotransporter (NCC) to subapical cytoplasmic vesicles.

    Science.gov (United States)

    Lee, Donna H; Riquier, Anne D M; Yang, Li E; Leong, Patrick K K; Maunsbach, Arvid B; McDonough, Alicia A

    2009-04-01

    When blood pressure (BP) is elevated above baseline, a pressure natriuresis-diuresis response ensues, critical to volume and BP homeostasis. Distal convoluted tubule Na(+)-Cl(-) cotransporter (NCC) is regulated by trafficking between the apical plasma membrane (APM) and subapical cytoplasmic vesicles (SCV). We aimed to determine whether NCC trafficking contributes to pressure diuresis by decreasing APM NCC or compensates for increased volume flow to the DCT by increasing APM NCC. BP was raised 50 mmHg (high BP) in rats by arterial constriction for 5 or 20-30 min, provoking a 10-fold diuresis at both times. Kidneys were excised, and NCC subcellular distribution was analyzed by 1) sorbitol density gradient fractionation and immunoblotting and 2) immunoelectron microscopy (immuno-EM). NCC distribution did not change after 5-min high BP. After 20-30 min of high BP, 20% of NCC redistributed from low-density, APM-enriched fractions to higher density, endosome-enriched fractions, and, by quantitative immuno-EM, pool size of APM NCC decreased 14% and SCV pool size increased. Because of the time lag of the response, we tested the hypothesis that internalization of NCC was secondary to the decrease in ANG II that accompanies high BP. Clamping ANG II at a nonpressor level by coinfusion of captopril (12 microg/min) and ANG II (20 ng.kg(-1).min(-1)) during 30-min high BP reduced diuresis to eightfold and prevented redistribution of NCC from APM- to SCV-enriched fractions. We conclude that DCT NCC may participate in pressure natriuresis-diuresis by retraction out of apical plasma membranes and that the retraction is, at least in part, driven by the fall in ANG II that accompanies acute hypertension.

  15. Skeletal muscle sodium glucose co-transporters in older adults with type 2 diabetes undergoing resistance training

    Directory of Open Access Journals (Sweden)

    Francisco Castaneda, Jennifer E. Layne, Carmen Castaneda

    2006-01-01

    Full Text Available We examined the expression of the sodium-dependent glucose co-transporter system (hSGLT3 in skeletal muscle of Hispanic older adults with type 2 diabetes. Subjects (65±8 yr were randomized to resistance training (3x/wk, n=13 or standard of care (controls, n=5 for 16 weeks. Skeletal muscle hSGLT3 and GLUT4 mRNA transcript levels were determined by real time RT-PCR. hSGLT3 transcripts increased by a factor of ten following resistance training compared to control subjects (0.10, P=0.03. There were no differences in GLUT4 mRNA expression levels between groups. Protein expression levels of these transporters were confirmed by immunohistochemistry and Western blotting. hSGLT3 after resistance exercise was found not to be co-localized with the nicotinic acetylcholine receptor. The change in hSGLT3 transcript levels in the vastus lateralis muscle was positively correlated with glucose uptake, as measured by the change in muscle glycogen stores (r=0.53, P=0.02; and with exercise intensity, as measured by the change in muscle strength (r=0.73, P=0.001. Group assignment was be the only independent predictor of hSGLT3 transcript levels, explaining 68% of its variability (P=0.01. Our data show that hSGLT3, but not GLTU4, expression was enhanced in skeletal muscle after 16 weeks of resistance training. This finding suggests that hSGLT3, an insulin-independent glucose transporter, is activated with exercise and it may play a significant role in glycemic control with muscle contraction. The hSGLT3 exact mechanism is not well understood and requires further investigation. However its functional significance regarding a reduction of glucose toxicity and improvement of insulin resistance is the subject of ongoing research.

  16. Determinants of substrate and cation transport in the human Na+/dicarboxylate cotransporter NaDC3.

    Science.gov (United States)

    Schlessinger, Avner; Sun, Nina N; Colas, Claire; Pajor, Ana M

    2014-06-13

    Metabolic intermediates, such as succinate and citrate, regulate important processes ranging from energy metabolism to fatty acid synthesis. Cytosolic concentrations of these metabolites are controlled, in part, by members of the SLC13 gene family. The molecular mechanism underlying Na(+)-coupled di- and tricarboxylate transport by this family is understood poorly. The human Na(+)/dicarboxylate cotransporter NaDC3 (SLC13A3) is found in various tissues, including the kidney, liver, and brain. In addition to citric acid cycle intermediates such as α-ketoglutarate and succinate, NaDC3 transports other compounds into cells, including N-acetyl aspartate, mercaptosuccinate, and glutathione, in keeping with its dual roles in cell nutrition and detoxification. In this study, we construct a homology structural model of NaDC3 on the basis of the structure of the Vibrio cholerae homolog vcINDY. Our computations are followed by experimental testing of the predicted NaDC3 structure and mode of interaction with various substrates. The results of this study show that the substrate and cation binding domains of NaDC3 are composed of residues in the opposing hairpin loops and unwound portions of adjacent helices. Furthermore, these results provide a possible explanation for the differential substrate specificity among dicarboxylate transporters that underpin their diverse biological roles in metabolism and detoxification. The structural model of NaDC3 provides a framework for understanding substrate selectivity and the Na(+)-coupled anion transport mechanism by the human SLC13 family and other key solute carrier transporters.

  17. Expression of Na+/HCO3- co-transporter proteins (NBCs) in rat and human skeletal muscle

    DEFF Research Database (Denmark)

    Kristensen, Jonas Møller; Kristensen, Michael; Juel, Carsten

    2004-01-01

    AIM: Sodium/bicarbonate co-transport (NBC) has been suggested to have a role in muscle pH regulation. We investigated the presence of NBC proteins in rat and human muscle samples and the fibre type distribution of the identified NBCs. METHODS AND RESULTS: Western blotting of muscle homogenates...... and sarcolemmal membranes (sarcolemmal giant vesicles) were used to screen for the presence of NBCs. Immunohistochemistry was used for the subcellular localization. The functional test revealed that approximately half of the pH recovery in sarcolemmal vesicles produced from rat muscle is mediated by bicarbonate...

  18. Case of ketoacidosis by a sodium-glucose cotransporter 2 inhibitor in a diabetic patient with a low-carbohydrate diet

    OpenAIRE

    Hayami, Tomohide; KATO, Yoshiro; Kamiya, Hideki; Kondo, Masaki; Naito, Ena; Sugiura, Yukako; Kojima, Chika; Sato, Sami; Yamada, Yuichiro; Kasagi, Rina; Ando, Toshihito; Noda, Saeko; Nakai, Hiromi; Takada, Eriko; Asano, Emi

    2015-01-01

    We present a case of a 32-year-old diabetic woman with Prader–Willi syndrome who developed severe ketoacidosis caused by a sodium-glucose cotransporter 2 (SGLT2) inhibitor, a novel class of antihyperglycemic agents, during a strict low-carbohydrate diet. At admission, a serum glucose level of 191 mg/dL was relatively low, though laboratory evaluations showed severe ketoacidosis. This is the first report of ketoacidosis caused by a SGLT2 inhibitor. It is necessary to not only pay attention whe...

  19. Model analysis of effect of canagliflozin (Invokana), a sodium-glucose cotransporter 2 inhibitor, to alter plasma 1,5-anhydroglucitol.

    Science.gov (United States)

    Fortuna, Danielle; McCloskey, Laura J; Stickle, Douglas F

    2016-01-15

    Renal reabsorption of 1,5-anhydroglucitol (AG) is competitively inhibited by elevated glucose and leads to depleted plasma AG in diabetes. Plasma AG recovery in diabetes normally correlates with improved glycemic control. However, use of sodium-glucose co-transporter 2 (SGLT2) inhibitors (e.g., canagliflozin) to treat diabetes by inhibition of renal glucose reabsorption can negate this correlation, via an indirect effect (increase of renal filtrate glucose concentration) to inhibit AG reabsorption by sodium-glucose co-transporter 4 (SGLT4). Conversely, then, AG measurement might be useful as an independent marker for SGLT2 inhibitor activity. Using an AG mass balance model, we analyzed literature data on plasma AG before and after initiation of canagliflozin therapy (CT) to quantitatively characterize the effect of CT on AG reabsorption. According to model calculations, modest decreases (<5%) in fractional reabsorption of AG account for the drastic decrease in [AG] observed during CT. Decreases are predicted to be rapid (t1/2<3days) after CT initiation. CT negates the usual premise of AG measurement (that [AG] should increase with improved glycemic control). However, according to model calculations, a substantial and likely rapid effect of CT on [AG] means that AG measurement might provide an early marker for CT activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. General anaesthetics do not impair developmental expression of the KCC2 potassium-chloride cotransporter in neonatal rats during the brain growth spurt

    KAUST Repository

    Lacoh, Claudia Marvine

    2013-03-26

    BackgroundThe developmental transition from depolarizing to hyperpolarizing γ-aminobutyric acid-mediated neurotransmission is primarily mediated by an increase in the amount of the potassium-chloride cotransporter KCC2 during early postnatal life. However, it is not known whether early neuronal activity plays a modulatory role in the expression of total KCC2 mRNA and protein in the immature brain. As general anaesthetics are powerful modulators of neuronal activity, the purpose of this study was to explore how these drugs affect KCC2 expression during the brain growth spurt.MethodsWistar rat pups were exposed to either a single dose or 6 h of midazolam, propofol, or ketamine anaesthesia at postnatal days 0, 5, 10, or 15. KCC2 expression was assessed using immunoblotting, immunohistochemistry, or quantitative polymerase chain reaction analysis up to 3 days post-exposure in the medial prefrontal cortex.ResultsThere was a progressive and steep increase in the expression of KCC2 between birth and 2 weeks of age. Exposure to midazolam, propofol, or ketamine up to 6 h at any investigated stages of the brain growth spurt did not influence the expression of this cotransporter protein.ConclusionI.V. general anaesthetics do not seem to influence developmental expression of KCC2 during the brain growth spurt. © 2013 © The Author [2013].

  1. An Inverse Relationship Links Temperature and Substrate Apparent Affinity in the Ion-Coupled Cotransporters rGAT1 and KAAT1

    Directory of Open Access Journals (Sweden)

    Antonio Peres

    2012-11-01

    Full Text Available The effects of temperature on the operation of two ion-coupled cotransporters of the SLC6A family, namely rat GAT1 (SLC6A1 and KAAT1 (SLC6A19 from Manduca sexta, have been studied by electrophysiological means in Xenopus laevis oocytes expressing these proteins. The maximal transport-associated current (Imax and the apparent substrate affinity (K05 were measured. In addition to the expected increase in transport rate (Q10 = 3–6, both transporters showed greater K05 values (i.e., a decrease in apparent affinity at higher temperatures. The transport efficiency, estimated as Imax/K05, increased at negative potentials in both transporters, but did not show statistically significant differences with temperature. The observation that the apparent substrate affinity is inversely related to the transport rate suggests a kinetic regulation of this parameter. Furthermore, the present results indicate that the affinities estimated at room temperature for mammalian cotransporters may not be simply extrapolated to their physiological operating conditions.

  2. Altered expression of renal bumetanide-sensitive sodium-pota-ssium-2 chloride cotransporter and Cl- channel -K2 gene in angiotensin Ⅱ-infused hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    YE Tao; LIU Zhi-quan; SUN Chao-feng; ZHENG Yong; MA Ai-qun; FANG Yuan

    2005-01-01

    Background Little information is available regarding the effect of angiotensin Ⅱ (Ang Ⅱ) on the bumetanide-sensitive sodium-potassium-2 chloride cotransporter (NKCC2), the thiazide-sensitive sodium-chloride cotransporter (NCC), and the Cl- channel (CLC)-K2 at both mRNA and protein expression level in Ang Ⅱ-induced hypertensive rats. This study was conducted to investigate the influence of Ang Ⅱ with chronic subpressor infusion on nephron-specific gene expression of NKCC2, NCC and CLC-K2. Results Ang Ⅱ significantly increased blood pressure and up-regulated NKCC2 mRNA and protein expression in the kidney. Expression of CLC-K2 mRNA in the kidney increased 1.6 fold (P<0.05).There were no changes in NCC mRNA or protein expression in AngII-treated rats versus control. Conclusions Chronic subpressor Ang Ⅱ infusion can significantly alter NKCC2 and CLC-K2 mRNA expression in the kidney, and protein abundance of NKCC2 in kidney is positively regulated by Ang Ⅱ. These effects may contribute to enhanced renal Na+ and Cl- reabsorption in response to Ang Ⅱ.

  3. Activation of thiazide-sensitive co-transport by angiotensin II in the cyp1a1-Ren2 hypertensive rat.

    Directory of Open Access Journals (Sweden)

    Ali Ashek

    Full Text Available Transgenic rats with inducible expression of the mouse Ren2 gene were used to elucidate mechanisms leading to the development of hypertension and renal injury. Ren2 transgene activation was induced by administration of a naturally occurring aryl hydrocarbon, indole-3-carbinol (100 mg/kg/day by gastric gavage. Blood pressure and renal parameters were recorded in both conscious and anesthetized (butabarbital sodium; 120 mg/kg IP rats at selected time-points during the development of hypertension. Hypertension was evident by the second day of treatment, being preceded by reduced renal sodium excretion due to activation of the thiazide-sensitive sodium-chloride co-transporter. Renal injury was evident after the first day of transgene induction, being initially limited to the pre-glomerular vasculature. Mircoalbuminuria and tubuloinsterstitial injury developed once hypertension was established. Chronic treatment with either hydrochlorothiazide or an AT1 receptor antagonist normalized sodium reabsorption, significantly blunted hypertension and prevented renal injury. Urinary aldosterone excretion was increased ≈ 20 fold, but chronic mineralocorticoid receptor antagonism with spironolactone neither restored natriuretic capacity nor prevented hypertension. Spironolactone nevertheless ameliorated vascular damage and prevented albuminuria. This study finds activation of sodium-chloride co-transport to be a key mechanism in angiotensin II-dependent hypertension. Furthermore, renal vascular injury in this setting reflects both barotrauma and pressure-independent pathways associated with direct detrimental effects of angiotensin II and aldosterone.

  4. Bone effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Blevins, Thomas C; Farooki, Azeez

    2017-01-01

    Canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM), lowers blood glucose by inhibiting renal glucose reabsorption and increasing urinary glucose excretion. It has been reported that SGLT2 inhibitors may have potential adverse effects on bone, including increased fracture risk and decreased bone mineral density (BMD). Across clinical studies, canagliflozin was not associated with meaningful changes in serum or urine calcium, vitamin D, or parathyroid hormone. Minimal increases in serum phosphate and magnesium that were within normal limits were seen with canagliflozin versus placebo. Canagliflozin was associated with increases in serum collagen type 1 beta-carboxy telopeptide (beta-CTX), a bone resorption marker, and osteocalcin, a bone formation marker. Decreases in total hip BMD were seen with canagliflozin 100 and 300 mg versus placebo after 2 years (-1.7%, -2.1%, -0.8%; differences of -0.9% and -1.2%), but not at other skeletal sites (normal age-related bone loss, ~0.5-1.0%/year). Changes in beta-CTX and total hip BMD were significantly associated with weight loss, which is known to increase bone resorption markers and decrease BMD. Canagliflozin was associated with a higher fracture incidence in an interim analysis of the CANagliflozin cardioVascular Assessment Study (CANVAS) in patients with a history or high risk of cardiovascular disease (incidence per 100 patient-years of 1.6, 1.6, and 1.1 with canagliflozin 100 and 300 mg and placebo), but not in other clinical studies of patients with T2DM. Fractures tended to occur as early as 12 weeks after initiating treatment and were primarily located in the distal parts of the upper and lower extremities. The reason for increased fracture risk with canagliflozin treatment is unknown, but is likely not related to a direct effect of canagliflozin on bone-related biomarkers. Data from ongoing canagliflozin studies, including CANVAS, will

  5. Single-dose Pharmacokinetics and Pharmacodynamics of Canagliflozin, a Selective Inhibitor of Sodium Glucose Cotransporter 2, in Healthy Indian Participants.

    Science.gov (United States)

    Devineni, Damayanthi; Polidori, David; Curtin, Christopher; Stieltjes, Hans; Tian, Hong; Wajs, Ewa

    2016-01-01

    Canagliflozin, an orally active selective inhibitor of sodium glucose cotransporter 2, has been approved in several countries for the treatment of type 2 diabetes mellitus. This study assessed the pharmacokinetic (PK) and pharmacodynamic (PD) properties and tolerability of single-dose canagliflozin 200 or 300 mg in healthy Indian participants. In this Phase 1, single-center, open-label, 2-period crossover study, healthy adult participants were randomly assigned to receive a single dose of canagliflozin 200 mg in period 1, followed by canagliflozin 300 mg in period 2, or vice versa. The 2 periods were separated by a washout interval of 14 days. The PK and PD properties and tolerability of canagliflozin were assessed at prespecified time points. Of 15 randomized participants, 14 completed the study. After the administration of single doses of 200 and 300 mg, the mean (SD) Cmax values were 1792 (430) ng/mL and 2789 (941) ng/mL, respectively; AUC0-∞, values were 18,706 (3818) ng·h/mL and 28,207 (5901) ng·h/mL, respectively. The Tmax and t½ of canagliflozin were independent of dose (Tmax, 1.5 hours at both doses; t½, 13.0 and 12.6 hours with 200 and 300 mg). Over the first 4 hours, mean (SD) renal threshold for glucose (RTG) values were 60.8 (8.90) and 61.2 (7.04) mg/dL with the 200- and 300-mg doses, respectively. No effect on plasma glucose concentrations over 0 to 4 hours relative to baseline was observed with either dose. The only treatment-emergent adverse event (TEAE) reported in >1 participant was dizziness (2 participants with the 200-mg dose). None of the participants in the 300-mg group reported any TEAEs. No deaths, discontinuations due to TEAEs, or hypoglycemic episodes were reported. The mean plasma exposure (Cmax and AUC) to canagliflozin increased in a dose-dependent manner after the administration of single-dose oral canagliflozin 200 and 300 mg in these healthy Indian participants. The Tmax and t½ of canagliflozin appeared to be independent of

  6. Volume regulation in mammalian skeletal muscle: the role of sodium-potassium-chloride cotransporters during exposure to hypertonic solutions.

    Science.gov (United States)

    Lindinger, Michael I; Leung, Matthew; Trajcevski, Karin E; Hawke, Thomas J

    2011-06-01

    Controversy exists as to whether mammalian skeletal muscle is capable of volume regulation in response to changes in extracellular osmolarity despite evidence that muscle fibres have the required ion transport mechanisms to transport solute and water in situ. We addressed this issue by studying the ability of skeletal muscle to regulate volume during periods of induced hyperosmotic stress using single, mouse extensor digitorum longus (EDL) muscle fibres and intact muscle (soleus and EDL). Fibres and intact muscles were loaded with the fluorophore, calcein, and the change in muscle fluorescence and width (single fibres only) used as a metric of volume change. We hypothesized that skeletal muscle exposed to increased extracellular osmolarity would elicit initial cellular shrinkage followed by a regulatory volume increase (RVI) with the RVI dependent on the sodium–potassium–chloride cotransporter (NKCC). We found that single fibres exposed to a 35% increase in extracellular osmolarity demonstrated a rapid, initial 27–32% decrease in cell volume followed by a RVI which took 10-20 min and returned cell volume to 90–110% of pre-stimulus values. Within intact muscle, exposure to increased extracellular osmolarity of varying degrees also induced a rapid, initial shrinkage followed by a gradual RVI, with a greater rate of initial cell shrinkage and a longer time for RVI to occur with increasing extracellular tonicities. Furthermore, RVI was significantly faster in slow-twitch soleus than fast-twitch EDL. Pre-treatment of muscle with bumetanide (NKCC inhibitor) or ouabain (Na+,K+-ATPase inhibitor), increased the initial volume loss and impaired the RVI response to increased extracellular osmolarity indicating that the NKCC is a primary contributor to volume regulation in skeletal muscle. It is concluded that mouse skeletal muscle initially loses volume then exhibits a RVI when exposed to increases in extracellular osmolarity. The rate of RVI is dependent on the

  7. Incretins and selective renal sodium-glucose co-transporter 2 inhibitors in hypertension and coronary heart disease

    Institute of Scientific and Technical Information of China (English)

    Ramiro; A; Sanchez; Hugo; Sanabria; Cecilia; de; los; Santos; Agustin; J; Ramirez

    2015-01-01

    Hyperglycemia is associated with an increased risk of cardiovascular disease,and the consequences ofintensive therapy may depend on the mechanism of the anti-diabetic agent(s)used to achieve a tight control.In animal models,stable analogues of glucagon-like peptide-1(GLP-1)were able to reduce body weight and blood pressure and also had favorable effects on ischemia following coronary reperfusion.In a similar way,dipeptidyl peptidase IV(DPPIV)showed to have favorable effects in animal models of ischemia/reperfusion.This could be due to the fact that DPPIV inhibitors were able to prevent the breakdown of GLP-1 and glucose-dependent insulinotropic polypeptide,but they also decreased the degradation of several vasoactive peptides.Preclinical data for GLP-1,its derivatives and inhibitors of the DPPIV enzyme degradation suggests that these agents may be able to,besides controlling glycaemia,induce cardio-protective and vasodilator effects.Notwithstanding the many favorable cardiovascular effects of GLP-1/incretins reported in different studies,many questions remain unanswered due the limited number of studies in human beings that aim to examine the effects of GLP-1 on cardiovascular endpoints.For this reason,long-term trials searching for positive cardiovascular effects are now in process,such as the CAROLINA and CARMELINA trials,which are supported by small pilot studies performed in humans(and many more animal studies)with incretin-based therapies.On the other hand,selective renal sodium-glucose co-transporter 2 inhibitors were also evaluated in the prevention of cardiovascular outcomes in type 2 diabetes.However,it is quite early to draw conclusions,since data on cardiovascular outcomes and cardiovascular death are limited and long-term studies are still ongoing.In this review,we will analyze the mechanisms underlying the cardiovascular effects of incretins and,at the same time,we will present a critical position about the real value of these compounds in the

  8. Epigenetic suppression of potassium-chloride co-transporter 2 expression in inflammatory pain induced by complete Freund's adjuvant (CFA).

    Science.gov (United States)

    Lin, C-R; Cheng, J-K; Wu, C-H; Chen, K-H; Liu, C-K

    2017-02-01

    Multiple mechanisms contribute to the stimulus-evoked pain hypersensitivity that may be experienced after peripheral inflammation. Persistent pathological stimuli in many pain conditions affect the expression of certain genes through epigenetic alternations. The main purpose of our study was to investigate the role of epigenetic modification on potassium-chloride co-transporter 2 (KCC2) gene expression in the persistence of inflammatory pain. Persistent inflammatory pain was induced through the injection of complete Freund's adjuvant (CFA) in the left hind paw of rats. Acetyl-histone H3 and H4 level was determined by chromatin immunoprecipitation in the spinal dorsal horn. Pain behaviour and inhibitory synaptic function of spinal cord were determined before and after CFA injection. KCC2 expression was determined by real time RT-PCR and Western blot. Intrathecal KCC2 siRNA (2 μg per 10 μL per rat) or HDAC inhibitor (10 μg per 10 μL per rat) was injected once daily for 3 days before CFA injection. Persistent inflammatory pain epigenetically suppressed KCC2 expression through histone deacetylase (HDAC)-mediated histone hypoacetylation, resulting in decreased inhibitory signalling efficacy. KCC2 knock-down caused by intrathecal administration of KCC2 siRNA in naïve rats reduced KCC2 expression in the spinal cord, leading to sensitized pain behaviours and impaired inhibitory synaptic transmission in their spinal cords. Moreover, intrathecal HDAC inhibitor injection in CFA rats increased KCC2 expression, partially restoring the spinal inhibitory synaptic transmission and relieving the sensitized pain behaviour. These findings suggest that the transcription of spinal KCC2 is regulated by histone acetylation epigenetically following CFA. Persistent pain suppresses KCC2 expression through HDAC-mediated histone hypoacetylation and consequently impairs the inhibitory function of inhibitory interneurons. Drugs such as HDAC inhibitors that suppress the influences of

  9. Basolateral Na+/HCO3– cotransport activity is regulated by the dissociable Na+/H+ exchanger regulatory factor

    Science.gov (United States)

    Bernardo, Angelito A.; Kear, Felicidad T.; Santos, Anna V.P.; Ma, Jianfei; Steplock, Debra; Robey, R. Brooks; Weinman, Edward J.

    1999-01-01

    In the renal proximal tubule, the activities of the basolateral Na+/HCO3– cotransporter (NBC) and the apical Na+/H+ exchanger (NHE3) uniformly vary in parallel, suggesting that they are coordinately regulated. PKA-mediated inhibition of NHE3 is mediated by a PDZ motif–containing protein, the Na+/H+ exchanger regulatory factor (NHE-RF). Given the common inhibition of these transporters after protein kinase A (PKA) activation, we sought to determine whether NHE-RF also plays a role in PKA-regulated NBC activity. Renal cortex immunoblot analysis using anti-peptide antibodies directed against rabbit NHE-RF demonstrated the presence of this regulatory factor in both brush-border membranes (BBMs) and basolateral membranes (BLMs). Using a reconstitution assay, we found that limited trypsin digestion of detergent solubilized rabbit renal BLM preparations resulted in NBC activity that was unaffected by PKA activation. Co-reconstitution of these trypsinized preparations with a recombinant protein corresponding to wild-type rabbit NHE-RF restored the inhibitory effect of PKA on NBC activity in a concentration-dependent manner. NBC activity was inhibited 60% by 10–8M NHE-RF; this effect was not observed in the absence of PKA. Reconstitution with heat-denatured NHE-RF also failed to attenuate NBC activity. To establish further a physiologic role for NHE-RF in NBC regulation, the renal epithelial cell line B-SC-1, which lacks detectable endogenous NHE-RF expression, was engineered to express stably an NHE-RF transgene. NHE-RF–expressing B-SC-1 cells (B-SC-RF) exhibited markedly lower basal levels of NBC activity than did wild-type controls. Inhibition of NBC activity in B-SC-RF cells was enhanced after 10 μM of forskolin treatment, consistent with a postulated role for NHE-RF in mediating the inhibition of NBC activity by PKA. These findings not only suggest NHE-RF involvement in PKA-regulated NBC activity, but also provide a unique molecular mechanism whereby

  10. Functional interaction between CFTR and the sodium-phosphate co-transport type 2a in Xenopus laevis oocytes.

    Directory of Open Access Journals (Sweden)

    Naziha Bakouh

    Full Text Available BACKGROUND: A growing number of proteins, including ion transporters, have been shown to interact with Cystic Fibrosis Transmembrane conductance Regulator (CFTR. CFTR is an epithelial chloride channel that is involved in Cystic Fibrosis (CF when mutated; thus a better knowledge of its functional interactome may help to understand the pathophysiology of this complex disease. In the present study, we investigated if CFTR and the sodium-phosphate co-transporter type 2a (NPT2a functionally interact after heterologous expression of both proteins in Xenopus laevis oocytes. METHODOLOGY/FINDINGS: NPT2a was expressed alone or in combination with CFTR in X. laevis oocytes. Using the two-electrode voltage-clamp technique, the inorganic phosphate-induced current (IPi was measured and taken as an index of NPT2a activity. The maximal IPi for NPT2a substrates was reduced when CFTR was co-expressed with NPT2a, suggesting a decrease in its expression at the oolemna. This was consistent with Western blot analysis showing reduced NPT2a plasma membrane expression in oocytes co-expressing both proteins, whereas NPT2a protein level in total cell lysate was the same in NPT2a- and NPT2a+CFTR-oocytes. In NPT2a+CFTR- but not in NPT2a-oocytes, IPi and NPT2a surface expression were increased upon PKA stimulation, whereas stimulation of Exchange Protein directly Activated by cAMP (EPAC had no effect. When NPT2a-oocytes were injected with NEG2, a short amino-acid sequence from the CFTR regulatory domain that regulates PKA-dependent CFTR trafficking to the plasma membrane, IPi values and NPT2a membrane expression were diminished, and could be enhanced by PKA stimulation, thereby mimicking the effects of CFTR co-expression. CONCLUSION/PERSPECTIVES: We conclude that when both CFTR and NPT2a are expressed in X. laevis oocytes, CFTR confers to NPT2a a cAMPi-dependent trafficking to the membrane. This functional interaction raises the hypothesis that CFTR may play a role in

  11. Resistance of Abaca Somaclonal Variant Against Fusarium

    Directory of Open Access Journals (Sweden)

    RULLY DYAH PURWATI

    2007-12-01

    Full Text Available The objectives of this study were (i to evaluate responses against F. oxysporum f.sp. cubense (Foc infection of abaca variants regenerated using four different methods, (ii to determine initial root length and plant height effects on survival of inoculated abaca variants, and (iii to identify Foc resistance abaca variants. In the previous experiment, four abaca variant lines were regenerated from (i embryogenic calli (TC line, (ii ethyl methyl sulphonate (EMS treated embryogenic calli (EMS line, (iii EMS treated embryogenic calli, followed by in vitro selection on Foc culture filtrate (EMS+CF line, and (iv EMS treated embryogenic calli, followed by in vitro selection on fusaric acid (EMS+FA line. All abaca variants were grown in a glasshouse and inoculated with Banyuwangi isolate of Foc (Foc Bw. Initial root length (RL and plant height (PH of the abaca variants were recorded before inoculation, while scores of plant damage (SPD, and their survival were recorded at 60 days after inoculation (DAI. The results showed that the initial RL and PH did not affect survival of the tested abaca variants. Regardless of their initial RL and PH, susceptible abaca variants died before 60 DAI while resistance ones still survived. Abaca variants regenerated from single clump of embryogenic callus showed an array of responses against Foc Bw infection, indicating the existence of a mix cells population. The Foc Bw resistance abaca variants were successfully identified from four tested abaca variant lines, although with different frequencies. However, more Foc Bw resistance abaca plants were identified from EMS+CF line than the others. Using the developed procedures, 8 resistance abaca plants were identified from abaca cv. Tangongon and 12 from abaca cv. Sangihe-1.

  12. Semantic prioritization of novel causative genomic variants

    KAUST Repository

    Boudellioua, Imane

    2017-04-17

    Discriminating the causative disease variant(s) for individuals with inherited or de novo mutations presents one of the main challenges faced by the clinical genetics community today. Computational approaches for variant prioritization include machine learning methods utilizing a large number of features, including molecular information, interaction networks, or phenotypes. Here, we demonstrate the PhenomeNET Variant Predictor (PVP) system that exploits semantic technologies and automated reasoning over genotype-phenotype relations to filter and prioritize variants in whole exome and whole genome sequencing datasets. We demonstrate the performance of PVP in identifying causative variants on a large number of synthetic whole exome and whole genome sequences, covering a wide range of diseases and syndromes. In a retrospective study, we further illustrate the application of PVP for the interpretation of whole exome sequencing data in patients suffering from congenital hypothyroidism. We find that PVP accurately identifies causative variants in whole exome and whole genome sequencing datasets and provides a powerful resource for the discovery of causal variants.

  13. Fundamental Characteristics of Industrial Variant Specification Systems

    DEFF Research Database (Denmark)

    Hansen, Benjamin Loer; Hvam, Lars

    2004-01-01

    fundamental concepts related to this task, which are relevant to understand for academia and practitioners working with the subject. This is done through a description of variant specification tasks and typical aspects of system solutions. To support the description of variant specification tasks and systems...

  14. Beta-glucosidase I variants with improved properties

    Energy Technology Data Exchange (ETDEWEB)

    Bott, Richard R.; Kaper, Thijs; Kelemen, Bradley; Goedegebuur, Frits; Hommes, Ronaldus Wilhelmus; Kralj, Slavko; Kruithof, Paulien; Nikolaev, Igor; Van Der Kley, Wilhelmus Antonious Hendricus; Van Lieshout, Johannes Franciscus Thomas; Van Stigt Thans, Sander

    2016-09-20

    The present disclosure is generally directed to enzymes and in particular beta-glucosidase variants. Also described are nucleic acids encoding beta-glucosidase variants, compositions comprising beta-glucosidase variants, methods of using beta-glucosidase variants, and methods of identifying additional useful beta-glucosidase variants.

  15. The Na+/H+ exchanger NHE1, but not the Na+, HCO3- cotransporter NBCn1, regulates motility of MCF7 breast cancer cells expressing constitutively active ErbB2

    DEFF Research Database (Denmark)

    Lauritzen, Gitte; Stock, Christian-Martin; Lemaire, Justine;

    2012-01-01

    We and others have shown central roles of the Na(+)/H(+) exchanger NHE1 in cell motility. The aim of this study was to determine the roles of NHE1 and of the Na(+), HCO(3)(-) cotransporter NBCn1 in motility of serum-starved MCF-7 breast cancer cells expressing constitutively active ErbB2 (¿NErbB2...

  16. Local binary patterns new variants and applications

    CERN Document Server

    Jain, Lakhmi; Nanni, Loris; Lumini, Alessandra

    2014-01-01

    This book introduces Local Binary Patterns (LBP), arguably one of the most powerful texture descriptors, and LBP variants. This volume provides the latest reviews of the literature and a presentation of some of the best LBP variants by researchers at the forefront of textual analysis research and research on LBP descriptors and variants. The value of LBP variants is illustrated with reported experiments using many databases representing a diversity of computer vision applications in medicine, biometrics, and other areas. There is also a chapter that provides an excellent theoretical foundation for texture analysis and LBP in particular. A special section focuses on LBP and LBP variants in the area of face recognition, including thermal face recognition. This book will be of value to anyone already in the field as well as to those interested in learning more about this powerful family of texture descriptors.

  17. Histones in functional diversification. Core histone variants.

    Science.gov (United States)

    Pusarla, Rama-Haritha; Bhargava, Purnima

    2005-10-01

    Recent research suggests that minor changes in the primary sequence of the conserved histones may become major determinants for the chromatin structure regulating gene expression and other DNA-related processes. An analysis of the involvement of different core histone variants in different nuclear processes and the structure of different variant nucleosome cores shows that this may indeed be so. Histone variants may also be involved in demarcating functional regions of the chromatin. We discuss in this review why two of the four core histones show higher variation. A comparison of the status of variants in yeast with those from higher eukaryotes suggests that histone variants have evolved in synchrony with functional requirement of the cell.

  18. Fundamental Characteristics of Industrial Variant Specification Systems

    DEFF Research Database (Denmark)

    Hansen, Benjamin Loer; Hvam, Lars

    2004-01-01

    This paper focuses on the operational task of creating customised variants of industrial specifications (e.g. drawings, routings and bill-of-materials). Rooted in a lack of existing literature on the subject the paper describes the nature of variant specification systems. It introduces some funda...... examples. In general the paper discusses an important focus area within mass customization and build-to-order production: the nature of industrial variant specification systems.......This paper focuses on the operational task of creating customised variants of industrial specifications (e.g. drawings, routings and bill-of-materials). Rooted in a lack of existing literature on the subject the paper describes the nature of variant specification systems. It introduces some...

  19. Different Variants of Fundamental Portfolio

    Directory of Open Access Journals (Sweden)

    Tarczyński Waldemar

    2014-06-01

    Full Text Available The paper proposes the fundamental portfolio of securities. This portfolio is an alternative for the classic Markowitz model, which combines fundamental analysis with portfolio analysis. The method’s main idea is based on the use of the TMAI1 synthetic measure and, in limiting conditions, the use of risk and the portfolio’s rate of return in the objective function. Different variants of fundamental portfolio have been considered under an empirical study. The effectiveness of the proposed solutions has been related to the classic portfolio constructed with the help of the Markowitz model and the WIG20 market index’s rate of return. All portfolios were constructed with data on rates of return for 2005. Their effectiveness in 2006- 2013 was then evaluated. The studied period comprises the end of the bull market, the 2007-2009 crisis, the 2010 bull market and the 2011 crisis. This allows for the evaluation of the solutions’ flexibility in various extreme situations. For the construction of the fundamental portfolio’s objective function and the TMAI, the study made use of financial and economic data on selected indicators retrieved from Notoria Serwis for 2005.

  20. Chemokine gene variants in schizophrenia.

    Science.gov (United States)

    Dasdemir, Selcuk; Kucukali, Cem Ismail; Bireller, Elif Sinem; Tuzun, Erdem; Cakmakoglu, Bedia

    2016-08-01

    Background Chemokines are known to play a major role in driving inflammation and immune responses in several neuroinflammatory diseases, including multiple sclerosis, Alzheimer's disease and Parkinson's disease. Inflammation has also been implicated in the pathogenesis of schizophrenia. Aim We aimed to investigate a potential link between chemokines and schizophrenia and analyze the role of MCP-1-A2518G, SDF-1-3'A, CCR5-delta32, CCR5-A55029G, CXCR4-C138T and CCR2-V64I gene polymorphisms in the Turkish population. Methods Genotyping was conducted by PCR-RFLP based on 140 patients and 123 unrelated healthy controls to show the relation between chemokine gene variants and schizophrenia risk. Results Frequencies of CCR5-A55029G A genotypes and CCR5-A55029G AG genotypes were found higher in patients than the controls and even also CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes significantly associated according to Bonferroni correction. However, no significant association was found for any of the other polymorphisms with the risk of schizophrenia. Conclusions Our findings suggest that CCR5-A55029G polymorphisms and CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes might have association with schizophrenia pathogenesis.

  1. Using Bacterial Surrogates to Assess Pathogen Transport in the Subsurface: Laboratory and Field Indications of Co-Transport Considerations

    Science.gov (United States)

    Emelko, M.; Stimson, J. R.; McLellan, N. L.; Mesquita, M.

    2009-12-01

    processes such as RBF. Here, duplicate column studies were conducted to evaluate the transport of nano- and micro-sized polystyrene micropsheres, aerobic spores of Bacillus subtilis, PR772 bacteriophage, and pathogenic Salmonella typhimurium bacteria in a well-sorted fine sand (d 50 = 0.6 mm). A field validation experiment investigating transport of 1.5 µm polystyrene micropsheres and aerobic spores in and RBF system comprised of unconsolidated silty sand, gravel, and boulders was conducted. The column studies demonstrated that the presence of the aerobic spores resulted in increased removal of 4.5 µm microspheres frommicrosphere removal from removal. Microscopic examination of the samples also revealed extensive clumping of microspheres and microorganisms during the experiments conducted with aerobic spores. A field trial during which microspheres and spores of B. subtilis were injected into the subsurface provided corroborating evidence of a co-transport effect of aerobic spores by demonstrating ~1.6 log increase in 1.5 µm microsphere removal in the presence of aerobic spores.

  2. Field-scale evaluation of the co-transport impacts of Bacillus subtilis endospores on other pathogen surrogates

    Science.gov (United States)

    Stimson, J. R.; Chik, A. H.; Mesquita, M. M.; McLellan, N. L.; Emelko, M.

    2009-12-01

    spores (TAS) occurred in the native groundwater at an average concentration of 1.4 x 10-1 ± 5.9 x 10-2 (n = 21) spore mL-1. When B. subtilis endospores were injected at a concentration of 6.7 x 104 spores mL-1, TAS recovery at the extraction well exceeded natural levels by ~1-log. The increase in TAS concentration is attributed to B. subtilis spore injection. The removal of 1.5 µm microspheres was increased from ~7-log in the absence of injected B. subtilis spores to ~8-log in the presence of the spores. The increased microsphere removal when spores were present was presumably due to spore-microsphere aggregation and/or the enhanced co-attachment of microspheres and spores to mineral surfaces. This observed surrogate interaction must be considered in studies where more than one tracer is employed to estimate removal efficiency of riverbank filtration systems. An additional field-scale co-transport study, examining Bacillus spore interaction with E. coli and bacteriophage PRD-1, will be conducted to assess the degree of interference observed with other biocolloids.

  3. Histological variants of cutaneous Kaposi sarcoma

    Directory of Open Access Journals (Sweden)

    Pantanowitz Liron

    2008-07-01

    Full Text Available Abstract This review provides a comprehensive overview of the broad clinicopathologic spectrum of cutaneous Kaposi sarcoma (KS lesions. Variants discussed include: usual KS lesions associated with disease progression (i.e. patch, plaque and nodular stage; morphologic subtypes alluded to in the older literature such as anaplastic and telangiectatic KS, as well as several lymphedematous variants; and numerous recently described variants including hyperkeratotic, keloidal, micronodular, pyogenic granuloma-like, ecchymotic, and intravascular KS. Involuting lesions as a result of treatment related regression are also presented.

  4. Ultrasonographic imaging of papillary thyroid carcinoma variants

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jung Hee [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2017-04-15

    Ultrasonography (US) is routinely used to evaluate thyroid nodules. The US features of papillary thyroid carcinoma (PTC), the most common thyroid malignancy, include hypoechogenicity, spiculated/microlobulated margins, microcalcifications, and a nonparallel orientation. However, many PTC variants have been identified, some of which differ from the classic type of PTC in terms of biological behavior and clinical outcomes. This review describes the US features and clinical implications of the variants of PTC. With the introduction of active surveillance replacing immediate biopsy or surgical treatment of indolent, small PTCs, an understanding of the US characteristics of PTC variants will facilitate the individualized management of patients with PTC.

  5. Na+,HCO3--cotransport is functionally upregulated during human breast carcinogenesis and required for the inverted pH gradient across the plasma membrane

    DEFF Research Database (Denmark)

    Lee, Soojung; Mele, Marco; Vahl, Pernille

    2015-01-01

    and promoting cancer cell metabolism, proliferation, migration, and invasion. We investigated the effects of breast carcinogenesis on the mechanisms of cellular pH control using multicellular epithelial organoids freshly isolated from human primary breast carcinomas and matched normal breast tissue...... (~0.3 units of magnitude) in steady-state intracellular pH of human primary breast carcinomas compared to normal breast tissue. Na(+)/H(+)-exchange activity and steady-state intracellular pH in the absence of CO2/HCO3 (-) were practically unaffected by breast carcinogenesis. These effects were evident....... Intracellular pH was measured by fluorescence microscopy, while protein expression was investigated by immunofluorescence imaging and immunoblotting. We found that cellular net acid extrusion increased during human breast carcinogenesis due to enhanced Na(+),HCO3 (-)-cotransport, which created an alkaline shift...

  6. Benefits/risks of sodium-glucose co-transporter 2 inhibitor canagliflozin in women for the treatment of Type 2 diabetes.

    Science.gov (United States)

    Kushner, Pamela

    2016-06-01

    Sodium-glucose co-transporter 2 (SGLT2) inhibitors, such as canagliflozin, are used in patients with Type 2 diabetes mellitus (T2DM). In clinical studies, canagliflozin significantly reduced A1C, bodyweight and blood pressure, and was generally well tolerated with no increased risk of hypoglycemia. Most common adverse effects observed were genital mycotic infections and urinary tract infections, and increased urination. Approximately 10% of women treated with canagliflozin experienced a genital mycotic infection compared with 3% treated with placebo; those with a prior history were at greater risk. Approximately 9% of women treated with canagliflozin reported a urinary tract infection compared with 7% treated with placebo. Most adverse events were considered mild to moderate in intensity and responded to standard therapy. Treatment with canagliflozin was effective and generally well tolerated in both women (and men) with T2DM.

  7. Expression of Na+-d-glucose cotransporter SGLT2 in rodents is kidney-specific and exhibits sex and species differences

    OpenAIRE

    Sabolić, Ivan; Vrhovac, Ivana; Eror, Daniela Balen; Gerasimova, Maria; Rose, Michael; Breljak, Davorka; Ljubojević, Marija; Brzica, Hrvoje; Sebastiani, Anne; Thal, Serge C.; Sauvant, Christoph; Kipp, Helmut; Vallon, Volker; Koepsell, Hermann

    2012-01-01

    With a novel antibody against the rat Na+-d-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and pr...

  8. Case of ketoacidosis by a sodium-glucose cotransporter 2 inhibitor in a diabetic patient with a low-carbohydrate diet

    Science.gov (United States)

    Hayami, Tomohide; Kato, Yoshiro; Kamiya, Hideki; Kondo, Masaki; Naito, Ena; Sugiura, Yukako; Kojima, Chika; Sato, Sami; Yamada, Yuichiro; Kasagi, Rina; Ando, Toshihito; Noda, Saeko; Nakai, Hiromi; Takada, Eriko; Asano, Emi; Motegi, Mikio; Watarai, Atsuko; Kato, Koichi; Nakamura, Jiro

    2015-01-01

    We present a case of a 32-year-old diabetic woman with Prader–Willi syndrome who developed severe ketoacidosis caused by a sodium-glucose cotransporter 2 (SGLT2) inhibitor, a novel class of antihyperglycemic agents, during a strict low-carbohydrate diet. At admission, a serum glucose level of 191 mg/dL was relatively low, though laboratory evaluations showed severe ketoacidosis. This is the first report of ketoacidosis caused by a SGLT2 inhibitor. It is necessary to not only pay attention when using a SGLT2 inhibitor in patients following a low-carbohydrate diet, but also to start a low-carbohydrate diet in patients treated with a SGLT2 inhibitor because of a high risk for developing ketoacidosis. PMID:26417418

  9. Euglycemic Diabetic Ketoacidosis in a 27 year-old female patient with type-1-Diabetes treated with sodium-glucose cotransporter-2 (SGLT2) inhibitor Canagliflozin

    Science.gov (United States)

    Bader, Nimrah; Mirza, Lubna

    2016-01-01

    We are reporting a timely case of atypical euglycemic diabetic ketoacidosis in a type 1 diabetic patient treated with sodium-glucose cotransporter-2 (SGLT-2) inhibitor canagliflozin. The clinical history, physical examination findings and laboratory values are described. Other causes of acidosis such as salicylate toxicity or alcohol intoxication were excluded. Ketoacidosis resolved after increasing dextrose and insulin doses supporting the hypothesis that SGLT-2 inhibitors may lead to hypoinsulinemia. Euglycemic ketoacidosis did not recur in our patient after discontinuing canagliflozin. We recommend reserving SGLT2 inhibitor therapy to type 2 diabetics, discontinuing medication and treating patients presenting with ketoacidosis due to SGLT-2 inhibitors with higher concentrations of dextrose with appropriate doses of insulin to help resolve acidosis. PMID:27375734

  10. In vitro characterization of luseogliflozin, a potent and competitive sodium glucose co-transporter 2 inhibitor: Inhibition kinetics and binding studies.

    Science.gov (United States)

    Uchida, Saeko; Mitani, Akiko; Gunji, Emi; Takahashi, Teisuke; Yamamoto, Koji

    2015-05-01

    In this study, we evaluated an inhibition model of luseogliflozin on sodium glucose co-transporter 2 (SGLT2). We also analyzed the binding kinetics of the drug to SGLT2 protein using [(3)H]-luseogliflozin. Luseogliflozin competitively inhibited human SGLT2 (hSGLT2)-mediated glucose uptake with a Ki value of 1.10 nM. In the absence of glucose, [(3)H]-luseogliflozin exhibited a high affinity for hSGLT2 with a Kd value of 1.3 nM. The dissociation half-time was 7 h, suggesting that luseogliflozin dissociates rather slowly from hSGLT2. These profiles of luseogliflozin might contribute to the long duration of action of this drug.

  11. The Na+/PO4 cotransporter SLC20A1 gene labels distinct restricted subdomains of the developing pronephros in Xenopus and zebrafish embryos.

    Science.gov (United States)

    Nichane, Massimo; Van Campenhout, Claude; Pendeville, Hélène; Voz, Marianne L; Bellefroid, Eric J

    2006-10-01

    The embryonic pronephric kidneys of Xenopus and zebrafish serve as models to study vertebrate nephrogenesis. Recently, multiple subdomains within the Xenopus pronephros have been defined based on the expression of several transport proteins. In contrast, very few studies on the expression of renal transporters have been conducted in zebrafish. We have recently shown that the anterior and posterior segments of the zebrafish pronephric duct may correspond to the proximal tubule and distal tubule/duct compartments of the Xenopus and higher vertebrate pronephros, respectively. Here, we report the embryonic expression pattern of the Na(+)/PO(4) cotransporter SLC20A1 (PiT1/Glvr-1) gene encoding a type III sodium-dependent phosphate cotransporter in Xenopus and zebrafish. In Xenopus, SLC20A1 mRNA is expressed in the somitic mesoderm and lower level of expression is detected in the neural tube, eye, and neural crest cells. From stage 25, SLC20A1 is also detectable in the developing pronephros where expression is restricted to the late portion of the distal pronephric tubules. In zebrafish, SLC20A1 is transcribed from mid-somitogenesis in the anterior part of the pronephros where its expression corresponds to the rostral portion of the expression of other proximal tubule-specific markers. Outside the pronephros, lower level of SLC20A1 expression is also observed in the posterior cardinal and caudal veins. Based on the SLC20A1 expression domain and that of other transporters, four segments have been defined within the zebrafish pronephros. Together, our data reveal that the zebrafish and Xenopus pronephros have non-identical proximo-distal organizations.

  12. Downregulation of NCC and NKCC2 cotransporters by kidney-specific WNK1 revealed by gene disruption and transgenic mouse models.

    Science.gov (United States)

    Liu, Zhen; Xie, Jian; Wu, Tao; Truong, Thao; Auchus, Richard J; Huang, Chou-Long

    2011-03-01

    WNK1 (with-no-lysine[K]-1) is a protein kinase of which mutations cause a familial hypertension and hyperkalemia syndrome known as pseudohypoaldosteronism type 2 (PHA2). Kidney-specific (KS) WNK1 is an alternatively spliced form of WNK1 kinase missing most of the kinase domain. KS-WNK1 downregulates the Na(+)-Cl(-) cotransporter NCC by antagonizing the effect of full-length WNK1 when expressed in Xenopus oocytes. The physiological role of KS-WNK1 in the regulation of NCC and potentially other Na(+) transporters in vivo is unknown. Here, we report that mice overexpressing KS-WNK1 in the kidney exhibited renal Na(+) wasting, elevated plasma levels of angiotensin II and aldosterone yet lower blood pressure relative to wild-type littermates. Immunofluorescent staining revealed reduced surface expression of total and phosphorylated NCC and the Na(+)-K(+)-2Cl(-) cotransporter NKCC2 in the distal convoluted tubule and the thick ascending limb of Henle's loop, respectively. Conversely, mice with targeted deletion of exon 4A (the first exon for KS-WNK1) exhibited Na(+) retention, elevated blood pressure on a high-Na(+) diet and increased surface expression of total and phosphorylated NCC and NKCC2 in respective nephron segments. Thus, KS-WNK1 is a negative regulator of NCC and NKCC2 in vivo and plays an important role in the control of Na(+) homeostasis and blood pressure. These results have important implications to the pathogenesis of PHA2 with WNK1 mutations.

  13. Histone variants in plant transcriptional regulation.

    Science.gov (United States)

    Jiang, Danhua; Berger, Frédéric

    2017-01-01

    Chromatin based organization of eukaryotic genome plays a profound role in regulating gene transcription. Nucleosomes form the basic subunits of chromatin by packaging DNA with histone proteins, impeding the access of DNA to transcription factors and RNA polymerases. Exchange of histone variants in nucleosomes alters the properties of nucleosomes and thus modulates DNA exposure during transcriptional regulation. Growing evidence indicates the important function of histone variants in programming transcription during developmental transitions and stress response. Here we review how histone variants and their deposition machineries regulate the nucleosome stability and dynamics, and discuss the link between histone variants and transcriptional regulation in plants. This article is part of a Special Issue entitled: Plant Gene Regulatory Mechanisms and Networks, edited by Dr. Erich Grotewold and Dr. Nathan Springer.

  14. TCM Differential Treatment of Cough Variant Asthma

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhong-de; DENG Yi-qi; ZHANG Yu; HAN Yun; LIN Lin; CHAO En-xiang

    2010-01-01

    @@ Cough variant asthma (CVA), also called latent asthma or cough asthma, is a special type of asthma. With gradually deepened understanding of CVA in recent years, good curative effect has been achieved in TCM treatment of CVA.

  15. Variant profiling of evolving prokaryotic populations

    Science.gov (United States)

    Zojer, Markus; Schuster, Lisa N.; Schulz, Frederik; Pfundner, Alexander; Horn, Matthias

    2017-01-01

    Genomic heterogeneity of bacterial species is observed and studied in experimental evolution experiments and clinical diagnostics, and occurs as micro-diversity of natural habitats. The challenge for genome research is to accurately capture this heterogeneity with the currently used short sequencing reads. Recent advances in NGS technologies improved the speed and coverage and thus allowed for deep sequencing of bacterial populations. This facilitates the quantitative assessment of genomic heterogeneity, including low frequency alleles or haplotypes. However, false positive variant predictions due to sequencing errors and mapping artifacts of short reads need to be prevented. We therefore created VarCap, a workflow for the reliable prediction of different types of variants even at low frequencies. In order to predict SNPs, InDels and structural variations, we evaluated the sensitivity and accuracy of different software tools using synthetic read data. The results suggested that the best sensitivity could be reached by a union of different tools, however at the price of increased false positives. We identified possible reasons for false predictions and used this knowledge to improve the accuracy by post-filtering the predicted variants according to properties such as frequency, coverage, genomic environment/localization and co-localization with other variants. We observed that best precision was achieved by using an intersection of at least two tools per variant. This resulted in the reliable prediction of variants above a minimum relative abundance of 2%. VarCap is designed for being routinely used within experimental evolution experiments or for clinical diagnostics. The detected variants are reported as frequencies within a VCF file and as a graphical overview of the distribution of the different variant/allele/haplotype frequencies. The source code of VarCap is available at https://github.com/ma2o/VarCap. In order to provide this workflow to a broad community

  16. Bisalbuminemia. A new molecular variant, albumin Vancouver.

    Science.gov (United States)

    Frohlich, J; Kozier, J; Campbell, D J; Curnow, J V; Tárnoky, A L

    1978-11-01

    Of 18 members of a Fiji Indian family investigated, eight of the 12 males and two of the six females had an electrophoretically slow-type bisalbuminemia (alloalbuminemia). The albumin was characterized by the hiterto unique ratio of the two bands (Al A 35%: variant 65%), and by dye-binding studies and electrophoretic mobility in different media. The data suggest that this is a new variant, which we propose to call albumin Vancouver (Al Va).

  17. Another new variant of Bouveret's syndrome

    Institute of Scientific and Technical Information of China (English)

    Seong-Heum Park; Sang-Woo Lee; Tae-Jin Song

    2009-01-01

    Although Bouveret's syndrome, i.e. gastric outlet obstruction by a large gallstone impacted in the proximal duodenum secondary to a cholecystoduodenal fistula,is rare, its pathogenesis and clinical features are well characterized. However, existence of variant forms of the syndrome are not well known, and as far as we have been described in the English-language literature.We present a case of another new variant of Bouveret's syndrome in a 54-year-old Korean woman.

  18. Brief Analysis of Regional Variants in English%Brief Analysis of Regional Variants in Enghsh

    Institute of Scientific and Technical Information of China (English)

    张炳科

    2008-01-01

    It is universally acknowledged that regional variants exist in each language, for it is impossible that people always employ the same pronunciation or vocabulary or even grammar to express the same meaning no matter how large the scope in which a language is used may be. The author of this paper is just to exemplify some regional variants in English and to analyze the factors that account for the variants ,with the purpose of teaching English well in the most efficient way.

  19. Histone variants: key players of chromatin.

    Science.gov (United States)

    Biterge, Burcu; Schneider, Robert

    2014-06-01

    Histones are fundamental structural components of chromatin. Eukaryotic DNA is wound around an octamer of the core histones H2A, H2B, H3, and H4. Binding of linker histone H1 promotes higher order chromatin organization. In addition to their structural role, histones impact chromatin function and dynamics by, e.g., post-translational histone modifications or the presence of specific histone variants. Histone variants exhibit differential expression timings (DNA replication-independent) and mRNA characteristics compared to canonical histones. Replacement of canonical histones with histone variants can affect nucleosome stability and help to create functionally distinct chromatin domains. In line with this, several histone variants have been implicated in the regulation of cellular processes such as DNA repair and transcriptional activity. In this review, we focus on recent progress in the study of core histone variants H2A.X, H2A.Z, macroH2A, H3.3, and CENP-A, as well as linker histone H1 variants, their functions and their links to development and disease.

  20. Roles of Akt and SGK1 in the Regulation of Renal Tubular Transport

    Directory of Open Access Journals (Sweden)

    Nobuhiko Satoh

    2015-01-01

    Full Text Available A serine/threonine kinase Akt is a key mediator in various signaling pathways including regulation of renal tubular transport. In proximal tubules, Akt mediates insulin signaling via insulin receptor substrate 2 (IRS2 and stimulates sodium-bicarbonate cotransporter (NBCe1, resulting in increased sodium reabsorption. In insulin resistance, the IRS2 in kidney cortex is exceptionally preserved and may mediate the stimulatory effect of insulin on NBCe1 to cause hypertension in diabetes via sodium retention. Likewise, in distal convoluted tubules and cortical collecting ducts, insulin-induced Akt phosphorylation mediates several hormonal signals to enhance sodium-chloride cotransporter (NCC and epithelial sodium channel (ENaC activities, resulting in increased sodium reabsorption. Serum- and glucocorticoid-inducible kinase 1 (SGK1 mediates aldosterone signaling. Insulin can stimulate SGK1 to exert various effects on renal transporters. In renal cortical collecting ducts, SGK1 regulates the expression level of ENaC through inhibition of its degradation. In addition, SGK1 and Akt cooperatively regulate potassium secretion by renal outer medullary potassium channel (ROMK. Moreover, sodium-proton exchanger 3 (NHE3 in proximal tubules is possibly activated by SGK1. This review focuses on recent advances in understanding of the roles of Akt and SGK1 in the regulation of renal tubular transport.

  1. Beta-glucosidase variants and polynucleotides encoding same

    Energy Technology Data Exchange (ETDEWEB)

    Wogulis, Mark; Harris, Paul; Osborn, David

    2017-06-27

    The present invention relates to beta-glucosidase variants, e.g. beta-glucosidase variants of a parent Family GH3A beta-glucosidase from Aspergillus fumigatus. The present invention also relates to polynucleotides encoding the beta-glucosidase variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the beta-glucosidase variants.

  2. Maisonneuve-hyperplantarflexion variant ankle fracture.

    Science.gov (United States)

    Hinds, Richard M; Tran, Wesley H; Lorich, Dean G

    2014-11-01

    Maisonneuve fractures are rare ankle injuries, accounting for up to 7% of all ankle fractures. They consist of a proximal third fibula fracture, syndesmotic disruption, and medial ankle injury (either a deltoid ligament disruption or a medial malleolus fracture), and are often successfully managed with nonoperative treatment of the proximal fibula fracture and open reduction and internal fixation (ORIF) of the medial ankle injury and syndesmotic disruption. The hyperplantarflexion variant ankle fracture comprises approximately 7% of all ankle fractures and features dual posterior tibial lip fractures featuring a posterolateral fragment and a posteromedial fragment. Good functional results have been reported in the literature after ORIF of both the posterolateral and posteromedial fragments of this variant fracture that is not described by the Lauge-Hansen classification. In this report, the authors present the unique case of an isolated ankle fracture demonstrating characteristics of both a Maisonneuve fracture and a hyperplantarflexion variant ankle fracture. They also highlight the diagnostic imaging characteristics, including magnetic resonance imaging (MRI) and preoperative radiograph findings, surgical treatment, and postoperative clinical outcome for this patient with a Maisonneuve-hyperplantarflexion variant ankle fracture. To the authors' knowledge, this unique fracture pattern has not been reported previously in the literature. The authors conclude that although good results were seen postoperatively in this case, the importance of ORIF of both the posteromedial and posterolateral fragments of variant fractures cannot be overstated. They also found MRI to be a particularly helpful adjunct in formulating the correct diagnosis and treatment plan.

  3. Word Variant Identification in Old French

    Directory of Open Access Journals (Sweden)

    Peter Willett

    1997-01-01

    Full Text Available Increasing numbers of historical texts are available in machine-readable form, which retain the original spelling, which can be very different from the modern-day equivalents due to the natural evolution of a language, and because the concept of standardisation in spelling is comparatively modern. Among medieval vernacular writers, the same word could be spelled in different ways and the same author (or scribe might even use several alternative spellings in the same passage. Thus, we do not know,a priori, how many variant forms of a particular word there are in such texts, let alone what these variants might be. Searching on the modern equivalent, or even the commonest historical variant, of a particular word may thus fail to retrieve an appreciable number of occurrences unless the searcher already has an extensive knowledge of the language of the documents. Moreover, even specialist scholars may be unaware of some idiosyncratic variants. Here, we consider the use of computer methods to retrieve variant historical spellings.

  4. Changes in glucose-induced plasma active glucagon-like peptide-1 levels by co-administration of sodium–glucose cotransporter inhibitors with dipeptidyl peptidase-4 inhibitors in rodents

    OpenAIRE

    Takahiro Oguma; Chiaki Kuriyama; Keiko Nakayama; Yasuaki Matsushita; Kumiko Hikida; Minoru Tsuda-Tsukimoto; Akira Saito; Kenji Arakawa; Kiichiro Ueta; Masabumi Minami; Masaharu Shiotani

    2016-01-01

    We investigated whether structurally different sodium–glucose cotransporter (SGLT) 2 inhibitors, when co-administered with dipeptidyl peptidase-4 (DPP4) inhibitors, could enhance glucagon-like peptide-1 (GLP-1) secretion during oral glucose tolerance tests (OGTTs) in rodents. Three different SGLT inhibitors—1-(β-d-Glucopyranosyl)-4-chloro-3-[5-(6-fluoro-2-pyridyl)-2-thienylmethyl]benzene (GTB), TA-1887, and canagliflozin—were examined to assess the effect of chemical structure. Oral treatment...

  5. [Computation of the K+, Na+ and Cl- fluxes through plasma membrane of animal cell with Na+/K+ pump, NKCC, NC cotransporters, and ionic channels with and without non-Goldman rectification in K+ channels. Norma and apoptosis].

    Science.gov (United States)

    Rubashkin, A A; Iurinskaia, V E; Vereninov, A A

    2010-01-01

    The balance of K+, Na+ and Cl- fluxes through cell membrane with the Na+/K+ pump, ion channels and NKCC and NC cotransporters is considered. It is shown that all unidirectional K+, Na+ and Cl- fluxes through cell membrane, permeability coefficients of ion channels and membrane potential can be computed for balanced ion distribution between cell and the medium if K+, Na+ and Cl- concentration in cell water and three fluxes are known: total Cl- flux, total K+ influx and ouabain-inhibitable "pump" component of the K+ influx. Changes in the mortovalent ion balance in lymphoid cells U937 induced to apoptosis by 1 microM staurosporine are analyzed as an example. It is found that the apoptotic shift in ion and water balance in studied cells is caused by a decrease in the pump activity which is accompanied by a decrease in the integral permeability of Na+ channels without significant increase in K+ and Cl- channel permeabilities. Computation shows that only a small part of the total fluxes of K+, Na+ and Cl- accounts for the fluxes via NKCC and NC cotransporters. Therefore, cotransport fluxes can not be studied using inhibitors.

  6. Pharmacodynamics, efficacy and safety of sodium-glucose co-transporter type 2 (SGLT2) inhibitors for the treatment of type 2 diabetes mellitus.

    Science.gov (United States)

    Scheen, André J

    2015-01-01

    Inhibitors of sodium-glucose co-transporter type 2 (SGLT2) are proposed as a novel approach for the management of type 2 diabetes mellitus (T2DM). Several compounds are already available in many countries (dapagliflozin, canagliflozin, empagliflozin and ipragliflozin) and some others are in a late phase of development. The available SGLT2 inhibitors share similar pharmacokinetic characteristics, with a rapid oral absorption, a long elimination half-life allowing once-daily administration, an extensive hepatic metabolism mainly via glucuronidation to inactive metabolites, the absence of clinically relevant drug-drug interactions and a low renal elimination as parent drug. SGLT2 co-transporters are responsible for reabsorption of most (90 %) of the glucose filtered by the kidneys. The pharmacological inhibition of SGLT2 co-transporters reduces hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. The amount of glucose excreted in the urine depends on both the level of hyperglycaemia and the glomerular filtration rate. Results of numerous placebo-controlled randomised clinical trials of 12-104 weeks duration have shown significant reductions in glycated haemoglobin (HbA1c), resulting in a significant increase in the proportion of patients reaching HbA1c targets, and a significant lowering of fasting plasma glucose when SGLT2 inhibitors were administered as monotherapy or in addition to other glucose-lowering therapies including insulin in patients with T2DM. In head-to-head trials of up to 2 years, SGLT2 inhibitors exerted similar glucose-lowering activity to metformin, sulphonylureas or sitagliptin. The durability of the glucose-lowering effect of SGLT2 inhibitors appears to be better; however, this remains to be more extensively investigated. The risk of hypoglycaemia was much lower with SGLT2 inhibitors than with sulphonylureas and was similarly low as that reported with metformin, pioglitazone or sitagliptin

  7. Variants of Monteggia Type Injury: Case Reports

    Directory of Open Access Journals (Sweden)

    Kamudin NAF

    2015-03-01

    Full Text Available Background: Monteggia fracture-dislocation is rare in children. Various reports attest to its rarity, while recording the many variant of this injury. It is, therefore, easy to miss the diagnosis in the absence of proper clinical examination and radiographs. Case Report : This report highlights two rare variants of Monteggia fracture-dislocation seen in children. The first case was a 12-year old girl alleged to have fallen from a 15-feet tall tree and sustaining a combined type III Monteggia injury with ipsilateral Type II Salter-Harris injury of distal end radius with a metaphyseal fracture of the distal third of the ulna. The second case was a 13-year old who had sustained a closed fracture of atypical Type I Monteggia hybrid lesion, in a road traffic accident. Conclusion: This report highlights the rare variants of Monteggia fracture dislocation which could have been missed without proper clinical examinations and radiographs.

  8. Variants of Monteggia Type Injury: Case Reports

    Science.gov (United States)

    Firdouse, M; Han, CS; M Yusof, A

    2015-01-01

    Background Monteggia fracture-dislocation is rare in children. Various reports attest to its rarity, while recording the many variant of this injury. It is, therefore, easy to miss the diagnosis in the absence of proper clinical examination and radiographs. Case Report This report highlights two rare variants of Monteggia fracture-dislocation seen in children. The first case was a 12-year old girl alleged to have fallen from a 15- feet tall tree and sustaining a combined type III Monteggia injury with ipsilateral Type II Salter-Harris injury of distal end radius with a metaphyseal fracture of the distal third of the ulna. The second case was a 13-year old who had sustained a closed fracture of atypical Type I Monteggia hybrid lesion, in a road traffic accident. Conclusion This report highlights the rare variants of Monteggia fracture dislocation which could have been missed without proper clinical examinations and radiographs. PMID:28435591

  9. Genetics in psychiatry: common variant association studies

    Directory of Open Access Journals (Sweden)

    Buxbaum Joseph D

    2010-03-01

    Full Text Available Abstract Many psychiatric conditions and traits are associated with significant heritability. Genetic risk for psychiatric conditions encompass rare variants, identified due to major effect, as well as common variants, the latter analyzed by association analyses. We review guidelines for common variant association analyses, undertaking after assessing evidence of heritability. We highlight the importance of: suitably large sample sizes; an experimental design that controls for ancestry; careful data cleaning; correction for multiple testing; small P values for positive findings; assessment of effect size for positive findings; and, inclusion of an independent replication sample. We also note the importance of a critical discussion of any prior findings, biological follow-up where possible, and a means of accessing the raw data.

  10. A case of reninoma with variant angina

    Directory of Open Access Journals (Sweden)

    Hyung Ah Jo

    2014-06-01

    Full Text Available Reninoma is a tumor of the renal juxtaglomerular cell apparatus that causes hypertension and hypokalemia because of hypersecretion of renin. We present a case of a 29-year-old female patient with reninoma and concomitant variant angina. The patient had uncontrolled hypertension and elevated plasma renin activity and aldosterone levels. Imaging studies revealed a mass in the left kidney, which was further confirmed as a renin-producing lesion via selective venous catheterization. During the evaluation, the patient had acute-onset chest pain that was diagnosed as variant angina after a provocation test. After partial nephrectomy, the plasma renin activity and plasma aldosterone levels decreased and blood pressure normalized. We report a case of reninoma with variant angina.

  11. Hemoglobin variants: biochemical properties and clinical correlates.

    Science.gov (United States)

    Thom, Christopher S; Dickson, Claire F; Gell, David A; Weiss, Mitchell J

    2013-03-01

    Diseases affecting hemoglobin synthesis and function are extremely common worldwide. More than 1000 naturally occurring human hemoglobin variants with single amino acid substitutions throughout the molecule have been discovered, mainly through their clinical and/or laboratory manifestations. These variants alter hemoglobin structure and biochemical properties with physiological effects ranging from insignificant to severe. Studies of these mutations in patients and in the laboratory have produced a wealth of information on hemoglobin biochemistry and biology with significant implications for hematology practice. More generally, landmark studies of hemoglobin performed over the past 60 years have established important paradigms for the disciplines of structural biology, genetics, biochemistry, and medicine. Here we review the major classes of hemoglobin variants, emphasizing general concepts and illustrative examples.

  12. Cryptanalysis of SIMON Variants with Connections

    DEFF Research Database (Denmark)

    Alizadeh, Javad; Alkhzaimi, Hoda A.; Aref, Mohammad Reza

    2014-01-01

    SIMON is a family of 10 lightweight block ciphers published by Beaulieu et al. from the United States National Security Agency (NSA). A cipher in this family with K-bit key and N-bit block is called SIMONN/K. We present several linear characteristics for reduced-round SIMON32/64 that can be used...... the presented observations do not directly yield an attack, but provide a basis for further analysis for the specific SIMON variant. Finally, we exploit a connection between linear and differential characteristics for SIMON to construct linear characteristics for different variants of reduced-round SIMON. Our...

  13. Histone variants and melanoma: facts and hypotheses.

    Science.gov (United States)

    Konstantinov, Nikifor K; Ulff-Møller, Constance J; Dimitrov, Stefan

    2016-07-01

    Melanoma is the most aggressive form of skin cancer with rising incidence and morbidity. Despite advances in treatment, the 10-yr survival for patients with metastatic disease is less than 10%. During the past few years, ongoing research on different epigenomic aberrations in melanoma has catalyzed better understanding of its pathogenesis and identification of new therapeutics. In our review, we will focus on the role of histone variants, key epigenetic players in melanoma initiation and progression. Specifically, incorporation of histone variants enables additional layers of chromatin structure, and here, we will describe how alterations in this epigenetic behavior impact melanoma.

  14. Variant profiling of evolving prokaryotic populations

    Directory of Open Access Journals (Sweden)

    Markus Zojer

    2017-02-01

    Full Text Available Genomic heterogeneity of bacterial species is observed and studied in experimental evolution experiments and clinical diagnostics, and occurs as micro-diversity of natural habitats. The challenge for genome research is to accurately capture this heterogeneity with the currently used short sequencing reads. Recent advances in NGS technologies improved the speed and coverage and thus allowed for deep sequencing of bacterial populations. This facilitates the quantitative assessment of genomic heterogeneity, including low frequency alleles or haplotypes. However, false positive variant predictions due to sequencing errors and mapping artifacts of short reads need to be prevented. We therefore created VarCap, a workflow for the reliable prediction of different types of variants even at low frequencies. In order to predict SNPs, InDels and structural variations, we evaluated the sensitivity and accuracy of different software tools using synthetic read data. The results suggested that the best sensitivity could be reached by a union of different tools, however at the price of increased false positives. We identified possible reasons for false predictions and used this knowledge to improve the accuracy by post-filtering the predicted variants according to properties such as frequency, coverage, genomic environment/localization and co-localization with other variants. We observed that best precision was achieved by using an intersection of at least two tools per variant. This resulted in the reliable prediction of variants above a minimum relative abundance of 2%. VarCap is designed for being routinely used within experimental evolution experiments or for clinical diagnostics. The detected variants are reported as frequencies within a VCF file and as a graphical overview of the distribution of the different variant/allele/haplotype frequencies. The source code of VarCap is available at https://github.com/ma2o/VarCap. In order to provide this workflow to

  15. The current state of clinical interpretation of sequence variants.

    Science.gov (United States)

    Hoskinson, Derick C; Dubuc, Adrian M; Mason-Suares, Heather

    2017-01-31

    Accurate and consistent variant classification is required for Precision Medicine. But clinical variant classification remains in its infancy. While recent guidelines put forth jointly by the American College of Medical Genetics and Genomics (ACMG) and Association of Molecular Pathology (AMP) for the classification of Mendelian variants has advanced the field, the degree of subjectivity allowed by these guidelines can still lead to inconsistent classification across clinical molecular genetic laboratories. In addition, there are currently no such guidelines for somatic cancer variants, only published institutional practices. Additional variant classification guidelines, including disease- or gene-specific criteria, along with inter-laboratory data sharing is critical for accurate and consistent variant interpretation.

  16. Cellobiohydrolase I gene and improved variants

    Science.gov (United States)

    Adney, William S.; Decker, Stephen R.; Mc Carter, Suzanne; Baker, John O.; Nieves, Raphael; Himmel, Michael E.; Vinzant, Todd B.

    2008-05-20

    The disclosure provides a method for preparing an active exoglucanase in a heterologous host of eukaryotic origin. The method includes mutagenesis to reduce glycosylation of the exoglucanase when expressed in a heterologous host. It is further disclosed a method to produce variant cellobiohydrolase that is stable at high temperature through mutagenesis.

  17. Developing consistent pronunciation models for phonemic variants

    CSIR Research Space (South Africa)

    Davel, M

    2006-09-01

    Full Text Available from a lexicon containing variants. In this paper we (the authors) address both these issues by creating ‘pseudo-phonemes’ associated with sets of ‘generation restriction rules’ to model those pronunciations that are consistently realised as two or more...

  18. Mining Process Variants: Goals and Issues

    NARCIS (Netherlands)

    Li, C.; Reichert, M.U.; Wombacher, A.

    2008-01-01

    Recently, Process-Aware Information Systems (PAIS) were introduced, which allow for dynamic process and service changes. This, in turn, has led to a large number of process model variants, which are difficult to maintain and expensive to configure. This paper deals with goals and issues related to t

  19. Splicing variants of porcine synphilin-1

    DEFF Research Database (Denmark)

    Larsen, Knud Erik; Madsen, Lone Bruhn; Farajzadeh, Leila

    2015-01-01

    RNA was investigated by RNAseq. The presented work reports the molecular cloning and characterization of the porcine (Sus scrofa) synphilin-1 cDNA (SNCAIP) and three splice variants hereof. The porcine SNCAIP cDNA codes for a protein (synphilin-1) of 919 amino acids which shows a high similarity to human (90...

  20. Report of a rare anatomic variant

    DEFF Research Database (Denmark)

    De Brucker, Y; Ilsen, B; Muylaert, C;

    2015-01-01

    We report the CT findings in a case of partial anomalous pulmonary venous return (PAPVR) from the left upper lobe in an adult. PAPVR is an anatomic variant in which one to three pulmonary veins drain into the right atrium or its tributaries, rather than into the left atrium. This results in a lef...

  1. Splicing variants of porcine synphilin-1

    Directory of Open Access Journals (Sweden)

    Knud Larsen

    2015-09-01

    Full Text Available Parkinson's disease (PD, idiopathic and familial, is characterized by degradation of dopaminergic neurons and the presence of Lewy bodies (LB in the substantia nigra. LBs contain aggregated proteins of which α-synuclein is the major component. The protein synphilin-1 interacts and colocalizes with α-synuclein in LBs. The aim of this study was to isolate and characterize porcine synphilin-1 and isoforms hereof with the future perspective to use the pig as a model for Parkinson's disease. The porcine SNCAIP cDNA was cloned by reverse transcriptase PCR. The spatial expression of SNCAIP mRNA was investigated by RNAseq. The presented work reports the molecular cloning and characterization of the porcine (Sus scrofa synphilin-1 cDNA (SNCAIP and three splice variants hereof. The porcine SNCAIP cDNA codes for a protein (synphilin-1 of 919 amino acids which shows a high similarity to human (90% and to mouse (84% synphilin-1. Three shorter transcript variants of the synphilin-1 gene were identified, all lacking one or more exons. SNCAIP transcripts were detected in most examined organs and tissues and the highest expression was found in brain tissues and lung. Conserved splicing variants and a novel splice form of synhilin-1 were found in this study. All synphilin-1 isoforms encoded by the identified transcript variants lack functional domains important for protein degradation.

  2. HLogo: a parallel Haskell variant of Netlogo

    NARCIS (Netherlands)

    N. Bezirgiannis (Nikolaos); Prasetya, I.S.W.B.; Sakellariou, I.

    2016-01-01

    textabstractAgent-based Modeling (ABM) has become quite popular to the simulation community for its usability and wide area of applicability. However, speed is not usually a trait that ABM tools are characterized of attaining. This paper presents HLogo, a parallel variant of the NetLogo ABM framewor

  3. PIN1 gene variants in Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Siedlecki Janusz

    2009-11-01

    Full Text Available Abstract Background Peptidyl-prolyl isomerase, NIMA-interacting 1 (PIN1 plays a significant role in the brain and is implicated in numerous cellular processes related to Alzheimer's disease (AD and other neurodegenerative conditions. There are confounding results concerning PIN1 activity in AD brains. Also PIN1 genetic variation was inconsistently associated with AD risk. Methods We performed analysis of coding and promoter regions of PIN1 in early- and late-onset AD and frontotemporal dementia (FTD patients in comparison with healthy controls. Results Analysis of eighteen PIN1 common polymorphisms and their haplotypes in EOAD, LOAD and FTD individuals in comparison with the control group did not reveal their contribution to disease risk. In six unrelated familial AD patients four novel PIN1 sequence variants were detected. c.58+64C>T substitution that was identified in three patients, was located in an alternative exon. In silico analysis suggested that this variant highly increases a potential affinity for a splicing factor and introduces two intronic splicing enhancers. In the peripheral leukocytes of one living patient carrying the variant, a 2.82 fold decrease in PIN1 expression was observed. Conclusion Our data does not support the role of PIN1 common polymorphisms as AD risk factor. However, we suggest that the identified rare sequence variants could be directly connected with AD pathology, influencing PIN1 splicing and/or expression.

  4. New genetic variants associated with prostate cancer

    Science.gov (United States)

    Researchers have newly identified 23 common genetic variants -- one-letter changes in DNA known as single-nucleotide polymorphisms or SNPs -- that are associated with risk of prostate cancer. These results come from an analysis of more than 10 million SNP

  5. Histone Variants in Development and Diseases

    Institute of Scientific and Technical Information of China (English)

    Ping Chen; Jicheng Zhao; Guohong Li

    2013-01-01

    Eukaryotic genomic DNA is highly packaged into chromatin by histones to fit inside the nucleus.Other than the bulk packaging role of canonical histones with an expression peak at S phase and replication-coupled deposition,different histone variants have evolved distinct regulatory mechanisms for their expression,deposition and functional implications.The diversity of histone variants results in structural plasticity of chromatin and highlights functionally distinct chromosomal domain,which plays critical roles in development from a fertilized egg into a complex organism,as well as in aging and diseases.However,the mechanisms of this fundamental process are poorly understood so far.It is of particular interest to investigate how the variants are incorporated into chromatin and mark specific chromatin states to regulate gene expression,and how they are involved in development and diseases.In this review,we focus on recent progress in studies of epigenetic regulation of three extensively investigated variants including H2A.Z,macroH2A and H3.3,and their functional implications in development and diseases.

  6. A compendium of genetic variant data

    DEFF Research Database (Denmark)

    Cardoso, Joao; Schöning, Lars Yannik; Herrgard, Markus

    2014-01-01

    Laboratory strains are genetically unstable if exposed to selective pressure as encountered, for example, during molecular cloning, fermentation, or adaptive laboratory evolution experiments. This genetic variation is the consequence of an adaptation process of the microorganism to stress...... obtained from distinct experiments. This compendium of genetic variant is a critical step to develop approaches to automatically and systematically characterize mutated strains in the future....

  7. Gene variants as risk factors for gastroschisis

    Science.gov (United States)

    Yang, Wei; Schultz, Kathleen; Tom, Lauren; Lin, Bin; Carmichael, Suzan L.; Lammer, Edward J.; Shaw, Gary M.

    2016-01-01

    In a population‐based case‐control study in California of 228 infants, we investigated 75 genetic variants in 20 genes and risk of gastroschisis with regard to maternal age, race/ethnicity, vitamin use, and smoking exposure. We hypothesized that genes related to vascular compromise may interact with environmental factors to affect the risk of gastroschisis. Haplotypes were constructed for 75 gene variants using the HaploView program. Risk for gastroschisis associated with each gene variant was calculated for both the homozygotes and the heterozygotes, with the homozygous wildtypes as the referent. Risks were estimated as odds ratios (ORs) with 95% confidence intervals (CIs) by logistic regression. We found 11 gene variants with increased risk and four variants with decreased risk of gastroschisis for heterozygous (ORh) or homozygous variants (ORv) genotypes. These included NOS3 (rs1036145) ORh = 0.4 (95% CI: 0.2–0.7); NOS3 (rs10277237) ORv = 2.7 (95% CI: 1.3–6.0); ADD1 (rs12503220) ORh = 2.9 (95% CI: 1.6–5.4), GNB3 (rs5443) ORh = 0.2 (95% CI: 0.1–0.5), ORv = 0.4 (95% CI: 0.2–0.9); ICAM1 (rs281428) ORv = 6.9 (95% CI: 2.1–22.9), ICAM1 (rs3093030) ORv = 2.6 (95% CI: 1.2–5.6); ICAM4 (rs281438) ORv = 4.9 (95% CI: 1.4–16.6), ICAM5 (rs281417) ORh = 2.1 (95% CI: 1.1–4.1), ORv = 4.8 (95% CI: 1.7–13.6); ICAM5 (rs281440) ORh = 23.7 (95% CI: 5.5–102.5), ORv = 20.6 (95% CI: 3.4–124.3); ICAM5 (rs2075741) ORv = 2.2 (95% CI: 1.1–4.4); NAT1 ORv = 0.3 (95% CI: 0.1–0.9). There were additional associations between several gene variants and gastroschisis among women aged 20–24 and among mothers with and without vitamin use. NOS3, ADD1, ICAM1, ICAM4, and ICAM5 warrant further investigation in additional populations and with the interaction of additional environmental exposures. © 2016 Wiley Periodicals, Inc. PMID:27616475

  8. Taurine Inhibits K+-Cl− Cotransporter KCC2 to Regulate Embryonic Cl− Homeostasis via With-no-lysine (WNK) Protein Kinase Signaling Pathway*

    Science.gov (United States)

    Inoue, Koichi; Furukawa, Tomonori; Kumada, Tatsuro; Yamada, Junko; Wang, Tianying; Inoue, Rieko; Fukuda, Atsuo

    2012-01-01

    GABA inhibits mature neurons and conversely excites immature neurons due to lower K+-Cl− cotransporter 2 (KCC2) expression. We observed that ectopically expressed KCC2 in embryonic cerebral cortices was not active; however, KCC2 functioned in newborns. In vitro studies revealed that taurine increased KCC2 inactivation in a phosphorylation-dependent manner. When Thr-906 and Thr-1007 residues in KCC2 were substituted with Ala (KCC2T906A/T1007A), KCC2 activity was facilitated, and the inhibitory effect of taurine was not observed. Exogenous taurine activated the with-no-lysine protein kinase 1 (WNK1) and downstream STE20/SPS1-related proline/alanine-rich kinase (SPAK)/oxidative stress response 1 (OSR1), and overexpression of active WNK1 resulted in KCC2 inhibition in the absence of taurine. Phosphorylation of SPAK was consistently higher in embryonic brains compared with that of neonatal brains and down-regulated by a taurine transporter inhibitor in vivo. Furthermore, cerebral radial migration was perturbed by a taurine-insensitive form of KCC2, KCC2T906A/T1007A, which may be regulated by WNK-SPAK/OSR1 signaling. Thus, taurine and WNK-SPAK/OSR1 signaling may contribute to embryonic neuronal Cl− homeostasis, which is required for normal brain development. PMID:22544747

  9. Analysis of ileal sodium/bile acid cotransporter and related nuclear receptor genes in a family with multiple cases of idiopathic bile acid malabsorption

    Institute of Scientific and Technical Information of China (English)

    Marco Montagnani; Anna Abrahamsson; Cecilia G(a)lman; G(o)sta Eggertsen; Hanns-Ulrich Marschall; Elisa Ravaioli; Curt Einarsson; Paul A Dawson

    2006-01-01

    The etiology of most cases of idiopathic bile acid malabsorption (TBAM) is unknown. Tn this study, a Swedish family with bile acid malabsorption in three consecutive generations was screened for mutations in the ileal apical sodium-bile acid cotransporter gene (ASBT; gene symbol, SLC10A2) and in the genes for several of the nuclear receptors known to be important for ASBT expression: the farnesoid X receptor (FXR)and peroxisome proliferator activated receptor alpha (PPARα). The patients presented with a clinical history of idiopathic chronic watery diarrhea, which was responsive to cholestyramine treatment and consistent with IBAM. Bile acid absorption was determined using 75Se-homocholic acid taurine(SeHCAT); bile acid synthesis was estimated by measuring the plasma levels of 7α-hydroxy-4-cholesten-3-one (C4). The ASBT,FXR, and PPARα genes in the affected and unaffected family members were analyzed using single stranded conformation polymorphism (SSCP), denaturing HPLC,and direct sequencing. No ASBT mutations were identified and the ASBT gene did not segregate with the bile acid malabsorption phenotype. Similarly, no mutations or polymorphisms were identified in the FXR or PPARα genes associated with the bile acid malabsorption phenotype. These studies indicate that the intestinal bile acid malabsorption in these patients cannot be attributed to defects in ASBT. In the absence of apparent ileal disease, alternative explanations such as accelerated transit through the small intestine may be responsible for the IBAM.

  10. Safe and pragmatic use of sodium–glucose co-transporter 2 inhibitors in type 2 diabetes mellitus: South Asian Federation of Endocrine Societies consensus statement

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2017-01-01

    Full Text Available Diabetes prevalence shows a continuous increasing trend in South Asia. Although well-established treatment modalities exist for type 2 diabetes mellitus (T2DM management, they are limited by their side effect profile. Sodium–glucose co-transporter 2 inhibitors (SGLT2i with their novel insulin-independent renal action provide improved glycemic control, supplemented by reduction in weight and blood pressure, and cardiovascular safety. Based on the clinical outcomes with SGLT2i in patients with T2DM, treatment strategies that make a “good clinical sense” are desirable. Considering the peculiar lifestyle, body types, dietary patterns (long duration religious fasts, and the hot climate of the South Asian population, a unanimous decision was taken to design specific, customized guidelines for T2DM treatment strategies in these regions. The panel met for a discussion three times so as to get a consensus for the guidelines, and only unanimous consensus was included. After careful consideration of the quality and strength of the available evidence, the executive summary of this consensus statement was developed based on the American Association of Clinical Endocrinologists/American College of Endocrinology protocol.

  11. Effect of Sodium Glucose Cotransporter 2 Inhibitors With Low SGLT2/SGLT1 Selectivity on Circulating Glucagon-Like Peptide 1 Levels in Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Takebayashi, Kohzo; Inukai, Toshihiko

    2017-09-01

    Sodium glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic drugs that improve glycemic control by inhibiting reabsorption of glucose filtered through the renal glomerulus. Use of drugs in this class has increased because of their effect of decreasing body weight and a low risk for hypoglycemia, in addition to a relatively strong glucose-lowering effect. SGLT2 inhibitors such as canagliflozin and sotagliflozin (a SGLT1/SGLT2 dual inhibitor) also have a mild or moderate intestinal and renal SGLT1 inhibitory effect because of their relatively weak selectivity for SGLT2 over SGLT1. Recent evidence shows that these SGLT2 inhibitors with low SGLT2/SGLT1 selectivity elevate the level of circulating glucagon like peptide-1 (GLP-1), an incretin hormone that promotes insulin secretion in pancreatic β cells. This effect probably occurs partly via inhibition of intestinal SGLT1, and the elevation of active GLP-1 levels is especially apparent when these drugs are co-administered with dipeptidyl peptidase 4 (DPP4) inhibitors. These findings suggest that a combination of canagliflozin or sotagliflozin and a DPP4 inhibitor can provide a beneficial effect associated with elevation of circulating active GLP-1 and may serve as a treatment for patients with type 2 diabetes.

  12. Immunolocalization of Na+/K+-ATPase and Na+/K+/2Cl- cotransporter in the tubular epithelia of sea snake salt glands.

    Science.gov (United States)

    Babonis, L S; Hyndman, K A; Lillywhite, H B; Evans, D H

    2009-12-01

    The sublingual salt gland is the primary site of salt excretion in sea snakes; however, little is known about the mechanisms mediating ion excretion. Na(+)/K(+)-ATPase (NKA) and Na(+)/K(+)/2Cl(-) cotransporter (NKCC) are two proteins known to regulate membrane potential and drive salt secretion in most vertebrate secretory cells. We hypothesized that NKA and NKCC would localize to the basolateral membranes of the principal cells comprising the tubular epithelia of sea snake salt glands. Although there is evidence of NKA activity in salt glands from several species of sea snake, the localization of NKA and NKCC and other potential ion transporters remains unstudied. Using histology and immunohistochemistry, we localized NKA and NKCC in salt glands from three species of laticaudine sea snake: Laticauda semifasciata, L. laticaudata, and L. colubrina. Antibody specificity was confirmed using Western blots. The compound tubular glands of all three species were found to be composed of serous secretory epithelia, and NKA and NKCC were abundant in the basolateral membranes. These results are consistent with the morphology of secretory epithelia found in the rectal salt glands of marine elasmobranchs, the nasal glands of marine birds and the gills of teleost fishes, suggesting a similar function in regulating ion secretion.

  13. Irbesartan, an FDA approved drug for hypertension and diabetic nephropathy, is a potent inhibitor for hepatitis B virus entry by disturbing Na(+)-dependent taurocholate cotransporting polypeptide activity.

    Science.gov (United States)

    Wang, Xue-jun; Hu, Wei; Zhang, Ting-yu; Mao, Ying-ying; Liu, Nan-nan; Wang, Sheng-qi

    2015-08-01

    The liver-specific Na(+)-dependent taurocholate cotransporting polypeptide (NTCP) was recently identified as an entry receptor for hepatitis B virus (HBV) hepatotropic infection. In this study, an NTCP-overexpressing HepG2 cell line named HepG2.N9 susceptible to HBV infection was established using transcription activator-like effector nucleases (TALEN) technology. Using this cell line, irbesartan, the new NTCP-interfering molecule reported recently, was demonstrated here to effectively inhibit HBV infection with an IC50 of 3.3μM for hepatitis B e antigen (HBeAg) expression and exhibited no obvious cytotoxicity up to 1000μM. Irbesartan suppressed HBV uptake weakly but inhibited HBV covalently closed circular DNA (cccDNA) formation efficiently at physiological temperature. These results suggested that irbesartan targeted HBV infection at a post-uptake prior to cccDNA formation step such as the cell membrane fusion. Based on these findings, irbesartan, an FDA approved drug for hypertension and diabetic nephropathy, could be a potential candidate for treatment of HBV infection although further in vivo experiments are required.

  14. Thiazide diuretics directly induce osteoblast differentiation and mineralized nodule formation by interacting with a sodium chloride co-transporter in bone.

    Science.gov (United States)

    Dvorak, Melita M; De Joussineau, Cyrille; Carter, D Howard; Pisitkun, Trairak; Knepper, Mark A; Gamba, Gerardo; Kemp, Paul J; Riccardi, Daniela

    2007-09-01

    Thiazide diuretics are used worldwide as a first-choice drug for patients with uncomplicated hypertension. In addition to their antihypertensive effect, thiazides increase bone mineral density and reduce the prevalence of fractures. Traditionally, these effects have been attributed to increased renal calcium reabsorption that occurs secondary to the inhibition of the thiazide-sensitive sodium chloride cotransporter (NCC) in the distal tubule. The aim of the current study was to determine whether thiazides exert a direct bone-forming effect independent of their renal action. We found that the osteoblasts of human and rat bone also express NCC, suggesting that these bone-forming cells may be an additional target for thiazides. In vitro, NCC protein was virtually absent in proliferating human and fetal rat osteoblasts, whereas its expression dramatically increased during differentiation. Thiazides did not affect osteoblast proliferation, but directly stimulated the production of the osteoblast differentiation markers runt-related transcription factor 2 (runx2) and osteopontin. Using overexpression/knockdown studies in fetal rat calvarial cells, we show that thiazides increase the formation of mineralized nodules, but loop diuretics do not. Overall, our study demonstrates that thiazides directly stimulate osteoblast differentiation and bone mineral formation independent of their effects in the kidney. Therefore, in addition to their use as antihypertensive drugs, our results suggest that thiazides may find a role in the prevention and treatment of osteoporosis.

  15. Sodium-Glucose Linked Cotransporter-2 Inhibition Does Not Attenuate Disease Progression in the Rat Remnant Kidney Model of Chronic Kidney Disease.

    Directory of Open Access Journals (Sweden)

    Yanling Zhang

    Full Text Available Pharmacological inhibition of the proximal tubular sodium-glucose linked cotransporter-2 (SGLT2 leads to glycosuria in both diabetic and non-diabetic settings. As a consequence of their ability to modulate tubuloglomerular feedback, SGLT2 inhibitors, like agents that block the renin-angiotensin system, reduce intraglomerular pressure and single nephron GFR, potentially affording renoprotection. To examine this further we administered the SGLT2 inhibitor, dapagliflozin, to 5/6 (subtotally nephrectomised rats, a model of progressive chronic kidney disease (CKD that like CKD in humans is characterised by single nephron hyperfiltration and intraglomerular hypertension and where angiotensin converting enzyme inhibitors and angiotensin receptor blockers are demonstrably beneficial. When compared with untreated rats, both sham surgery and 5/6 nephrectomised rats that had received dapagliflozin experienced substantial glycosuria. Nephrectomised rats developed hypertension, heavy proteinuria and declining GFR that was unaffected by the administration of dapagliflozin. Similarly, SGLT2 inhibition did not attenuate the extent of glomerulosclerosis, tubulointerstitial fibrosis or overexpression of the profibrotic cytokine, transforming growth factor-ß1 mRNA in the kidneys of 5/6 nephrectomised rats. While not precluding beneficial effects in the diabetic setting, these findings indicate that SGLT2 inhibition does not have renoprotective effects in this classical model of progressive non-diabetic CKD.

  16. Intramolecular and intermolecular fluorescence resonance energy transfer in fluorescent protein-tagged Na-K-Cl cotransporter (NKCC1): sensitivity to regulatory conformational change and cell volume.

    Science.gov (United States)

    Pedersen, Meike; Carmosino, Monica; Forbush, Biff

    2008-02-01

    To examine the structure and function of the Na-K-Cl cotransporter, NKCC1, we tagged the transporter with cyan (CFP) and yellow (YFP) fluorescent proteins and measured fluorescence resonance energy transfer (FRET) in stably expressing human embryonic kidney cell lines. Fluorescent protein tags were added at the N-terminal residue between the regulatory domain and the membrane domain and within a poorly conserved region of the C terminus. Both singly and doubly tagged NKCC1s were appropriately trafficked to the cell membrane and were fully functional; regulation was normal except when YFP was inserted near the regulatory domain, in which case activation occurred only upon incubation with calyculin A. Quenching of YFP fluorescence by Cl(-) provided a ratiometric indicator of intracellular [Cl(-)]. All of the CFP/YFP NKCC pairs exhibited some level of FRET, demonstrating the presence of dimers or higher multimers in functioning NKCC1. With YFP near the regulatory domain and CFP in the C terminus, we recorded a 6% FRET change signaling the regulatory phosphorylation event. On the other hand, when the probe was placed at the extreme N terminus, such changes were not seen, presumably due to the length and predicted flexibility of the N terminus. Substantial FRET changes were observed contemporaneous with cell volume changes, possibly reflective of an increase in molecular crowding upon cell shrinkage.

  17. Transport behavior of hairless mouse skin during constant current DC iontophoresis, part 2: iontophoresis of nonionic molecules with cotransport of polystyrene sulfonate oligomers.

    Science.gov (United States)

    Liddell, Mark R; Li, S Kevin; Higuchi, William I

    2011-07-01

    The purpose of this study was to characterize changes that occur in the iontophoretic transport of nonionic probe permeants in hairless mouse skin epidermal membrane from the anode to cathode when polystyrene sulfonate (PSS) oligomers are cotransported from the cathode to anode. The experiments were conducted with trace levels of the nonionic probe permeants: urea, mannitol, and raffinose. In order to systematically assess changes that occur as a result of having PSS in the cathodal chamber, the steady-state transport parameters of the membrane and the experimental permeability coefficients of the probe permeants were determined and compared with results obtained from earlier baseline experiments where both the cathodal and anodal chamber media were phosphate buffered saline. In addition, the physicochemical properties of the PSS solutions were determined including the solution viscosity and conductance as well as the mobilities of individual PSS oligomers. The effective pore radii of the transport pathways were calculated using a theoretical expression based on simultaneous diffusion and electroosmosis. Compared with the baseline results, the calculated radii were found to have increased up to around twofold and the iontophoretic fluxes of the probe permeants increased by as much sixfold.

  18. CD8(+) T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension.

    Science.gov (United States)

    Liu, Yunmeng; Rafferty, Tonya M; Rhee, Sung W; Webber, Jessica S; Song, Li; Ko, Benjamin; Hoover, Robert S; He, Beixiang; Mu, Shengyu

    2017-01-09

    Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8(+) T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8(+) T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8(+) T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K(+) channel Kir4.1, and stimulation of the Cl(-) channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension.

  19. WNK-SPAK-NCC cascade revisited: WNK1 stimulates the activity of the Na-Cl cotransporter via SPAK, an effect antagonized by WNK4.

    Science.gov (United States)

    Chávez-Canales, María; Zhang, Chong; Soukaseum, Christelle; Moreno, Erika; Pacheco-Alvarez, Diana; Vidal-Petiot, Emmanuelle; Castañeda-Bueno, María; Vázquez, Norma; Rojas-Vega, Lorena; Meermeier, Nicholas P; Rogers, Shaunessy; Jeunemaitre, Xavier; Yang, Chao-Ling; Ellison, David H; Gamba, Gerardo; Hadchouel, Juliette

    2014-11-01

    The with-no-lysine (K) kinases, WNK1 and WNK4, are key regulators of blood pressure. Their mutations lead to familial hyperkalemic hypertension (FHHt), associated with an activation of the Na-Cl cotransporter (NCC). Although it is clear that WNK4 mutants activate NCC via Ste20 proline-alanine-rich kinase, the mechanisms responsible for WNK1-related FHHt and alterations in NCC activity are not as clear. We tested whether WNK1 modulates NCC through WNK4, as predicted by some models, by crossing our recently developed WNK1-FHHt mice (WNK1(+/FHHt)) with WNK4(-/-) mice. Surprisingly, the activated NCC, hypertension, and hyperkalemia of WNK1(+/FHHt) mice remain in the absence of WNK4. We demonstrate that WNK1 powerfully stimulates NCC in a WNK4-independent and Ste20 proline-alanine-rich kinase-dependent manner. Moreover, WNK4 decreases the WNK1 and WNK3-mediated activation of NCC. Finally, the formation of oligomers of WNK kinases through their C-terminal coiled-coil domain is essential for their activity toward NCC. In conclusion, WNK kinases form a network in which WNK4 associates with WNK1 and WNK3 to regulate NCC. © 2014 American Heart Association, Inc.

  20. Generation and analysis of the thiazide-sensitive Na+ -Cl- cotransporter (Ncc/Slc12a3) Ser707X knockin mouse as a model of Gitelman syndrome.

    Science.gov (United States)

    Yang, Sung-Sen; Lo, Yi-Fen; Yu, I-Shing; Lin, Shu-Wha; Chang, Tai-Hsiang; Hsu, Yu-Juei; Chao, Tai-Kuang; Sytwu, Huey-Kang; Uchida, Shinichi; Sasaki, Sei; Lin, Shih-Hua

    2010-12-01

    Gitelman syndrome (GS) is characterized by salt-losing hypotension, hypomagnesemia, hypokalemic metabolic alkalosis, and hypocalciuria. To better model human GS caused by a specific mutation in the thiazide-sensitive Na(+) -Cl(-) cotransporter (NCC) gene SLC12A3, we generated a nonsense Ncc Ser707X knockin mouse corresponding to human p.Ser710X (c.2135C>A), a recurrent mutation with severe phenotypes in Chinese GS patients. Compared with wild-type or heterozygous littermates, homozygous (Hom) knockin mice fully recapitulated the phenotype of human GS. The markedly reduced Ncc mRNA and virtually absent Ncc protein expression in kidneys of Hom mice was primarily due to nonsense-mediated mRNA decay (NMD) surveillance mechanisms. Expression of epithelial Na(+) channel (Enac), Ca(2+) channels (Trpv5 and Trpv6), and K(+) channels (Romk1 and maxi-K) were significantly increased. Late distal convoluted tubules (DCT) volume was increased and DCT cell ultrastructure appeared intact. High K(+) intake could not correct hypokalemia but caused a further increase in maxi-K but not Romk1 expression. Renal tissue from a patient with GS also showed the enhanced TRPV5 and ROMK1 expression in distal tubules. We suggest that the upregulation of TRPV5/6 and of ROMK1 and Maxi-K may contribute to hypocalciuria and hypokalemia in Ncc Ser707X knockin mice and human GS, respectively. © 2010 Wiley-Liss, Inc.

  1. KCNJ10 determines the expression of the apical Na-Cl cotransporter (NCC) in the early distal convoluted tubule (DCT1).

    Science.gov (United States)

    Zhang, Chengbiao; Wang, Lijun; Zhang, Junhui; Su, Xiao-Tong; Lin, Dao-Hong; Scholl, Ute I; Giebisch, Gerhard; Lifton, Richard P; Wang, Wen-Hui

    2014-08-12

    The renal phenotype induced by loss-of-function mutations of inwardly rectifying potassium channel (Kir), Kcnj10 (Kir4.1), includes salt wasting, hypomagnesemia, metabolic alkalosis and hypokalemia. However, the mechanism by which Kir.4.1 mutations cause the tubulopathy is not completely understood. Here we demonstrate that Kcnj10 is a main contributor to the basolateral K conductance in the early distal convoluted tubule (DCT1) and determines the expression of the apical Na-Cl cotransporter (NCC) in the DCT. Immunostaining demonstrated Kcnj10 and Kcnj16 were expressed in the basolateral membrane of DCT, and patch-clamp studies detected a 40-pS K channel in the basolateral membrane of the DCT1 of p8/p10 wild-type Kcnj10(+/+) mice (WT). This 40-pS K channel is absent in homozygous Kcnj10(-/-) (knockout) mice. The disruption of Kcnj10 almost completely eliminated the basolateral K conductance and decreased the negativity of the cell membrane potential in DCT1. Moreover, the lack of Kcnj10 decreased the basolateral Cl conductance, inhibited the expression of Ste20-related proline-alanine-rich kinase and diminished the apical NCC expression in DCT. We conclude that Kcnj10 plays a dominant role in determining the basolateral K conductance and membrane potential of DCT1 and that the basolateral K channel activity in the DCT determines the apical NCC expression possibly through a Ste20-related proline-alanine-rich kinase-dependent mechanism.

  2. CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension

    Science.gov (United States)

    Liu, Yunmeng; Rafferty, Tonya M.; Rhee, Sung W.; Webber, Jessica S.; Song, Li; Ko, Benjamin; Hoover, Robert S.; He, Beixiang; Mu, Shengyu

    2017-01-01

    Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8+ T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8+ T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8+ T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K+ channel Kir4.1, and stimulation of the Cl− channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension. PMID:28067240

  3. Gene Variant from Africa Linked to Black Obesity

    Science.gov (United States)

    ... html Gene Variant From Africa Linked to Black Obesity Study sees first biological pathway to weight gain ... identified an Africa-specific gene variant associated with obesity. The team found that about 1 percent of ...

  4. Rare variant density across the genome and across populations

    OpenAIRE

    Raska Paola; Zhu Xiaofeng

    2011-01-01

    Abstract Next-generation sequencing allows for a new focus on rare variant density for conducting analyses of association to disease and for narrowing down the genomic regions that show evidence of functionality. In this study we use the 1000 Genomes Project pilot data as distributed by Genetic Analysis Workshop 17 to compare rare variant densities across seven populations. We made the comparisons using regressions of rare variants on total variant counts per gene for each population and Taji...

  5. Combined analyses of 20 common obesity susceptibility variants

    DEFF Research Database (Denmark)

    Sandholt, Camilla Helene; Sparsø, Thomas; Grarup, Niels;

    2010-01-01

    Genome-wide association studies and linkage studies have identified 20 validated genetic variants associated with obesity and/or related phenotypes. The variants are common, and they individually exhibit small-to-modest effect sizes.......Genome-wide association studies and linkage studies have identified 20 validated genetic variants associated with obesity and/or related phenotypes. The variants are common, and they individually exhibit small-to-modest effect sizes....

  6. Processing of No-Release Variants in Connected Speech

    Science.gov (United States)

    LoCasto, Paul C.; Connine, Cynthia M.

    2011-01-01

    The cross modal repetition priming paradigm was used to investigate how potential lexically ambiguous no-release variants are processed. In particular we focus on segmental regularities that affect the variant's frequency of occurrence (voicing of the critical segment) and phonological context in which the variant occurs (status of the following…

  7. Rare ADH Variant Constellations are Specific for Alcohol Dependence

    OpenAIRE

    Zuo, Lingjun; Zhang, Heping; Malison, Robert T; Li, Chiang-shan R.; Zhang, Xiang-Yang; Wang, Fei; Lu, Lingeng; Lu, Lin; Wang, Xiaoping; Krystal, John H.; Zhang, Fengyu; Deng, Hong-Wen; Luo, Xingguang

    2012-01-01

    Aims: Some of the well-known functional alcohol dehydrogenase (ADH) gene variants (e.g. ADH1B*2, ADH1B*3 and ADH1C*2) that significantly affect the risk of alcohol dependence are rare variants in most populations. In the present study, we comprehensively examined the associations between rare ADH variants [minor allele frequency (MAF)

  8. GenOVa: a computer program to generate orientational variants

    OpenAIRE

    Cayron, Cyril

    2007-01-01

    A computer program called GenOVa, written in Python, calculates the orientational variants, the operators (special types of misorientations between variants) and the composition table associated with a groupoid structure. The variants can be represented by three-dimensional shapes or by pole figures.

  9. Variants in CUL4B are Associated with Cerebral Malformations

    NARCIS (Netherlands)

    Vulto-van Silfhout, Anneke T.; Nakagawa, Tadashi; Bahi-Buisson, Nadia; Haas, Stefan A.; Hu, Hao; Bienek, Melanie; Vissers, Lisenka E. L. M.; Gilissen, Christian; Tzschach, Andreas; Busche, Andreas; Muesebeck, Joerg; Rump, Patrick; Mathijssen, Inge B.; Avela, Kristiina; Somer, Mirja; Doagu, Fatma; Philips, Anju K.; Rauch, Anita; Baumer, Alessandra; Voesenek, Krysta; Poirier, Karine; Vigneron, Jacqueline; Amram, Daniel; Odent, Sylvie; Nawara, Magdalena; Obersztyn, Ewa; Lenart, Jacek; Charzewska, Agnieszka; Lebrun, Nicolas; Fischer, Ute; Nillesen, Willy M.; Yntema, Helger G.; Jarvela, Irma; Ropers, Hans-Hilger; de Vries, Bert B. A.; Brunner, Han G.; van Bokhoven, Hans; Raymond, F. Lucy; Willemsen, Michel A. A. P.; Chelly, Jamel; Xiong, Yue; Barkovich, A. James; Kalscheuer, Vera M.; Kleefstra, Tjitske; de Brouwer, Arjan P. M.

    2015-01-01

    Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating varia

  10. Variants in CUL4B are associated with cerebral malformations

    NARCIS (Netherlands)

    Vulto-van Silfhout, A.T.; Nakagawa, T.; Bahi-Buisson, N.; Haas, S.A.; Hu, H; Bienek, M.; Vissers, L.E.L.M.; Gilissen, C.F.H.A.; Tzschach, A.; Busche, A.; Musebeck, J.; Rump, P.; Mathijssen, I.B.; Avela, K.; Somer, M.; Doagu, F.; Philips, A.K.; Rauch, A.; Baumer, A.; Voesenek, K.E.J.; Poirier, K.; Vigneron, J.; Amram, D.; Odent, S.; Nawara, M.; Obersztyn, E.; Lenart, J.; Charzewska, A.; Lebrun, N.; Fischer, U.; Nillesen, W.M.; Yntema, H.G.; Jarvela, I.; Ropers, H.H.; Vries, B. de; Brunner, H.G.; Bokhoven, H. van; Raymond, F.L.; Willemsen, M.A.A.P.; Chelly, J.; Xiong, Y.; Barkovich, A.J.; Kalscheuer, V.M.; Kleefstra, T.; Brouwer, A.P.M. de

    2015-01-01

    Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating varia

  11. The power of multiplexed functional analysis of genetic variants.

    Science.gov (United States)

    Gasperini, Molly; Starita, Lea; Shendure, Jay

    2016-10-01

    New technologies have recently enabled saturation mutagenesis and functional analysis of nearly all possible variants of regulatory elements or proteins of interest in single experiments. Here we discuss the past, present, and future of such multiplexed (functional) assays for variant effects (MAVEs). MAVEs provide detailed insight into sequence-function relationships, and they may prove critical for the prospective clinical interpretation of genetic variants.

  12. Processing of No-Release Variants in Connected Speech

    Science.gov (United States)

    LoCasto, Paul C.; Connine, Cynthia M.

    2011-01-01

    The cross modal repetition priming paradigm was used to investigate how potential lexically ambiguous no-release variants are processed. In particular we focus on segmental regularities that affect the variant's frequency of occurrence (voicing of the critical segment) and phonological context in which the variant occurs (status of the following…

  13. Wham: Identifying Structural Variants of Biological Consequence.

    Science.gov (United States)

    Kronenberg, Zev N; Osborne, Edward J; Cone, Kelsey R; Kennedy, Brett J; Domyan, Eric T; Shapiro, Michael D; Elde, Nels C; Yandell, Mark

    2015-12-01

    Existing methods for identifying structural variants (SVs) from short read datasets are inaccurate. This complicates disease-gene identification and efforts to understand the consequences of genetic variation. In response, we have created Wham (Whole-genome Alignment Metrics) to provide a single, integrated framework for both structural variant calling and association testing, thereby bypassing many of the difficulties that currently frustrate attempts to employ SVs in association testing. Here we describe Wham, benchmark it against three other widely used SV identification tools-Lumpy, Delly and SoftSearch-and demonstrate Wham's ability to identify and associate SVs with phenotypes using data from humans, domestic pigeons, and vaccinia virus. Wham and all associated software are covered under the MIT License and can be freely downloaded from github (https://github.com/zeeev/wham), with documentation on a wiki (http://zeeev.github.io/wham/). For community support please post questions to https://www.biostars.org/.

  14. Discussing and managing hematologic germ line variants.

    Science.gov (United States)

    Kohlmann, Wendy; Schiffman, Joshua D

    2016-11-24

    With the introduction of genomic technologies, more hereditary cancer syndromes with hematologic malignancies are being described. Up to 10% of hematologic malignancies in children and adults may be the result of an underlying inherited genetic risk. Managing these patients with hereditary hematologic malignancies, including familial leukemia, remains a clinical challenge because there is little information about these relatively rare disorders. This article covers some of the issues related to the diagnosis and interpretation of variants associated with hereditary hematologic malignancies, including the importance of an accurate family history in interpreting genetic variants associated with disease. The challenges of screening other family members and offering the most appropriate early malignancy detection is also discussed. We now have a good opportunity to better define hereditary cancer syndromes with associated hematologic malignancies and contribute to clinically effective guidelines.

  15. Wham: Identifying Structural Variants of Biological Consequence.

    Directory of Open Access Journals (Sweden)

    Zev N Kronenberg

    2015-12-01

    Full Text Available Existing methods for identifying structural variants (SVs from short read datasets are inaccurate. This complicates disease-gene identification and efforts to understand the consequences of genetic variation. In response, we have created Wham (Whole-genome Alignment Metrics to provide a single, integrated framework for both structural variant calling and association testing, thereby bypassing many of the difficulties that currently frustrate attempts to employ SVs in association testing. Here we describe Wham, benchmark it against three other widely used SV identification tools-Lumpy, Delly and SoftSearch-and demonstrate Wham's ability to identify and associate SVs with phenotypes using data from humans, domestic pigeons, and vaccinia virus. Wham and all associated software are covered under the MIT License and can be freely downloaded from github (https://github.com/zeeev/wham, with documentation on a wiki (http://zeeev.github.io/wham/. For community support please post questions to https://www.biostars.org/.

  16. Fine-Mapping of Common Genetic Variants Associated with Colorectal Tumor Risk Identified Potential Functional Variants.

    Directory of Open Access Journals (Sweden)

    Mengmeng Du

    Full Text Available Genome-wide association studies (GWAS have identified many common single nucleotide polymorphisms (SNPs associated with colorectal cancer risk. These SNPs may tag correlated variants with biological importance. Fine-mapping around GWAS loci can facilitate detection of functional candidates and additional independent risk variants. We analyzed 11,900 cases and 14,311 controls in the Genetics and Epidemiology of Colorectal Cancer Consortium and the Colon Cancer Family Registry. To fine-map genomic regions containing all known common risk variants, we imputed high-density genetic data from the 1000 Genomes Project. We tested single-variant associations with colorectal tumor risk for all variants spanning genomic regions 250-kb upstream or downstream of 31 GWAS-identified SNPs (index SNPs. We queried the University of California, Santa Cruz Genome Browser to examine evidence for biological function. Index SNPs did not show the strongest association signals with colorectal tumor risk in their respective genomic regions. Bioinformatics analysis of SNPs showing smaller P-values in each region revealed 21 functional candidates in 12 loci (5q31.1, 8q24, 11q13.4, 11q23, 12p13.32, 12q24.21, 14q22.2, 15q13, 18q21, 19q13.1, 20p12.3, and 20q13.33. We did not observe evidence of additional independent association signals in GWAS-identified regions. Our results support the utility of integrating data from comprehensive fine-mapping with expanding publicly available genomic databases to help clarify GWAS associations and identify functional candidates that warrant more onerous laboratory follow-up. Such efforts may aid the eventual discovery of disease-causing variant(s.

  17. Fine-Mapping of Common Genetic Variants Associated with Colorectal Tumor Risk Identified Potential Functional Variants

    Science.gov (United States)

    Gala, Manish; Abecasis, Goncalo; Bezieau, Stephane; Brenner, Hermann; Butterbach, Katja; Caan, Bette J.; Carlson, Christopher S.; Casey, Graham; Chang-Claude, Jenny; Conti, David V.; Curtis, Keith R.; Duggan, David; Gallinger, Steven; Haile, Robert W.; Harrison, Tabitha A.; Hayes, Richard B.; Hoffmeister, Michael; Hopper, John L.; Hudson, Thomas J.; Jenkins, Mark A.; Küry, Sébastien; Le Marchand, Loic; Leal, Suzanne M.; Newcomb, Polly A.; Nickerson, Deborah A.; Potter, John D.; Schoen, Robert E.; Schumacher, Fredrick R.; Seminara, Daniela; Slattery, Martha L.; Hsu, Li; Chan, Andrew T.; White, Emily; Berndt, Sonja I.; Peters, Ulrike

    2016-01-01

    Genome-wide association studies (GWAS) have identified many common single nucleotide polymorphisms (SNPs) associated with colorectal cancer risk. These SNPs may tag correlated variants with biological importance. Fine-mapping around GWAS loci can facilitate detection of functional candidates and additional independent risk variants. We analyzed 11,900 cases and 14,311 controls in the Genetics and Epidemiology of Colorectal Cancer Consortium and the Colon Cancer Family Registry. To fine-map genomic regions containing all known common risk variants, we imputed high-density genetic data from the 1000 Genomes Project. We tested single-variant associations with colorectal tumor risk for all variants spanning genomic regions 250-kb upstream or downstream of 31 GWAS-identified SNPs (index SNPs). We queried the University of California, Santa Cruz Genome Browser to examine evidence for biological function. Index SNPs did not show the strongest association signals with colorectal tumor risk in their respective genomic regions. Bioinformatics analysis of SNPs showing smaller P-values in each region revealed 21 functional candidates in 12 loci (5q31.1, 8q24, 11q13.4, 11q23, 12p13.32, 12q24.21, 14q22.2, 15q13, 18q21, 19q13.1, 20p12.3, and 20q13.33). We did not observe evidence of additional independent association signals in GWAS-identified regions. Our results support the utility of integrating data from comprehensive fine-mapping with expanding publicly available genomic databases to help clarify GWAS associations and identify functional candidates that warrant more onerous laboratory follow-up. Such efforts may aid the eventual discovery of disease-causing variant(s). PMID:27379672

  18. Unusual variant of Cantrell′s pentalogy?

    Directory of Open Access Journals (Sweden)

    Kumar Basant

    2008-01-01

    Full Text Available A 12-hour-old male infant presented with prolapsed abdominal content through a defect on left side of chest wall with respiratory distress. A thorough clinical examination suggested absence of ectopia cordis, abdominal wall defect, and any bony anomaly. The child expired after 6 hours of admission because of respiratory distress and electrolyte imbalance. Is congenital defect of chest wall associated with diaphragmatic hernia without ectopia cordis and omphalocele, an unusual variant of Cantrell′s pentalogy?

  19. Variant position of the medial plantar nerve

    OpenAIRE

    Astik RB; Dave UH; Gajendra KS

    2011-01-01

    Knowledge of variation of position of the medial plantar nerve is important for the forefoot surgeon for plantar reconstruction, local injection therapy and an excision of interdigital neuroma. During routine dissection of 50-year-old female cadaver, we found the medial plantar nerve and vessels variably located between plantar aponeurosis and the muscles of the first layer of the sole of the right foot. Due to this variant position, the medial plantar nerve and vessels lose their protection ...

  20. Small colony variants and their clinical significance

    Directory of Open Access Journals (Sweden)

    Venkataramana Venkataramana

    2016-01-01

    Full Text Available Among the many factors that contribute to bacterial colonization, persistence and development of infection, the ability of microorganisms to form small colony variants (SCVs assumes great significance. Although bacteria require intrinsic virulence factors to cause pathogenesis, some of them regularly evolve mechanisms to evade immune mechanisms, become resistant to antibiotics, and sustain in the human/animal cells to cause chronic infections. This mini review highlights the recent advances in the study of SCVs.

  1. Unusual variant of Cantrell′s pentalogy?

    OpenAIRE

    Kumar Basant; Sharma S.; Kandpal Deepak; Agrawal L

    2008-01-01

    A 12-hour-old male infant presented with prolapsed abdominal content through a defect on left side of chest wall with respiratory distress. A thorough clinical examination suggested absence of ectopia cordis, abdominal wall defect, and any bony anomaly. The child expired after 6 hours of admission because of respiratory distress and electrolyte imbalance. Is congenital defect of chest wall associated with diaphragmatic hernia without ectopia cordis and omphalocele, an unusual variant of Cantr...

  2. Association of genetic variants with diabetic nephropathy

    Institute of Scientific and Technical Information of China (English)

    Saliha; Rizvi; Syed; Tasleem; Raza; Farzana; Mahdi

    2014-01-01

    Diabetic nephropathy accounts for the most serious microvascular complication of diabetes mellitus. It is suggested that the prevalence of diabetic nephropathy will continue to increase in future posing a major challenge to the healthcare system resulting in increased morbidity and mortality. It occurs as a result of interaction between both genetic and environmental factors in individuals with both type 1 and type 2 diabetes. Genetic susceptibility has been proposed as an important factor for the development and progression of diabetic nephropathy, and various research efforts are being executed worldwide to identify the susceptibility gene for diabetic nephropathy. Numerous single nucleotide polymorphisms have been found in various genes giving rise to various gene variants which have been found to play a major role in genetic susceptibility to diabetic nephropathy. The risk of developing diabetic nephropathy is increased several times by inheriting risk alleles at susceptibility loci of various genes like ACE, IL, TNF-α, COL4A1, e NOS, SOD2, APOE, GLUT, etc. The identification of these genetic variants at a biomarker level could thus, allow the detection of those individuals at high risk for diabetic nephropathy which could thus help in the treatment, diagnosis and early prevention of the disease. The present review discusses about the various gene variants found till date to be associated with diabetic nephropathy.

  3. Primary Aldosteronism and ARMC5 Variants

    Science.gov (United States)

    Zilbermint, Mihail; Xekouki, Paraskevi; Faucz, Fabio R.; Berthon, Annabel; Gkourogianni, Alexandra; Schernthaner-Reiter, Marie Helene; Batsis, Maria; Sinaii, Ninet; Quezado, Martha M.; Merino, Maria; Hodes, Aaron; Abraham, Smita B.; Libé, Rossella; Assié, Guillaume; Espiard, Stéphanie; Drougat, Ludivine; Ragazzon, Bruno; Davis, Adam; Gebreab, Samson Y.; Neff, Ryan; Kebebew, Electron; Bertherat, Jérôme; Lodish, Maya B.

    2015-01-01

    Context: Primary aldosteronism is one of the leading causes of secondary hypertension, causing significant morbidity and mortality. A number of genetic defects have recently been identified in primary aldosteronism, whereas we identified mutations in ARMC5, a tumor-suppressor gene, in cortisol-producing primary macronodular adrenal hyperplasia. Objective: We investigated a cohort of 56 patients who were referred to the National Institutes of Health for evaluation of primary aldosteronism for ARMC5 defects. Methods: Patients underwent step-wise diagnosis, with measurement of serum aldosterone and plasma renin activity followed by imaging, saline suppression and/or oral salt loading tests, plus adrenal venous sampling. Cortisol secretion was also evaluated; unilateral or bilateral adrenalectomy was performed, if indicated. DNA, protein, and transfection studies in H295R cells were conducted by standard methods. Results: We identified 12 germline ARMC5 genetic alterations in 20 unrelated and two related individuals in our cohort (39.3%). ARMC5 sequence changes in 6 patients (10.7%) were predicted to be damaging by in silico analysis. All affected patients carrying a variant predicted to be damaging were African Americans (P = .0023). Conclusions: Germline ARMC5 variants may be associated with primary aldosteronism. Additional cohorts of patients with primary aldosteronism and metabolic syndrome, particularly African Americans, should be screened for ARMC5 sequence variants because these may underlie part of the known increased predisposition of African Americans to low renin hypertension. PMID:25822102

  4. Warty Carcinoma Penis: An Uncommon Variant

    Science.gov (United States)

    Ghosh, Arnab; Shrestha, Santosh; Ghartimagar, Dilasma; Narasimhan, Raghavan; Talwar, OP

    2017-01-01

    Penile carcinoma frequency varies widely in different parts of the world and comprises 1–10% of all the malignancies in males. Majority of the cases of penile carcinoma are squamous cell carcinoma of penis comprising 60% to 70% of all cases. Warty carcinoma of penis is an unusual neoplasm and a variant of penile squamous cell carcinoma comprising 5%–10% of all the variants. The other histological variants include basaloid, verrucous, papillary, sarcomatous, mixed, and adenosquamous carcinoma. The various histological entities with an exophytic papillary lesions including warty carcinoma are together referred to as the “verruciform” group of neoplasms. The warty carcinoma has to be differentiated from these lesions and is typically distinguished by histological features of hyperkeratosis, arborescent papillomatosis, acanthosis, and prominent koilocytosis with nuclear pleomorphism. We present a case of 65-year-old male with growth measuring 6 × 4 cm in the penis who underwent total penectomy and was diagnosed as warty carcinoma penis. PMID:28154768

  5. Association of genetic variants with diabetic nephropathy.

    Science.gov (United States)

    Rizvi, Saliha; Raza, Syed Tasleem; Mahdi, Farzana

    2014-12-15

    Diabetic nephropathy accounts for the most serious microvascular complication of diabetes mellitus. It is suggested that the prevalence of diabetic nephropathy will continue to increase in future posing a major challenge to the healthcare system resulting in increased morbidity and mortality. It occurs as a result of interaction between both genetic and environmental factors in individuals with both type 1 and type 2 diabetes. Genetic susceptibility has been proposed as an important factor for the development and progression of diabetic nephropathy, and various research efforts are being executed worldwide to identify the susceptibility gene for diabetic nephropathy. Numerous single nucleotide polymorphisms have been found in various genes giving rise to various gene variants which have been found to play a major role in genetic susceptibility to diabetic nephropathy. The risk of developing diabetic nephropathy is increased several times by inheriting risk alleles at susceptibility loci of various genes like ACE, IL, TNF-α, COL4A1, eNOS, SOD2, APOE, GLUT, etc. The identification of these genetic variants at a biomarker level could thus, allow the detection of those individuals at high risk for diabetic nephropathy which could thus help in the treatment, diagnosis and early prevention of the disease. The present review discusses about the various gene variants found till date to be associated with diabetic nephropathy.

  6. Genetic variants associated with Crohn's disease

    Directory of Open Access Journals (Sweden)

    Michail S

    2013-07-01

    Full Text Available Sonia Michail,1 Gilberto Bultron,1 R William DePaolo2 1The University of Southern California, Children's Hospital of Los Angeles, Los Angeles, CA, USA; 2Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA Abstract: Crohn's disease is an immune-related disorder characterized by inflammation of the gastrointestinal mucosa, which can occur in any area throughout the digestive tract. This life-long disease commonly presents with abdominal pain, diarrhea, vomiting, and weight loss. While the exact etiology of this disease is largely unknown, it is thought to arise from an interaction between microbial, immunological, and environmental factors in a genetically susceptible host, whereby the immune system attacks the intestine as it cross reacts against gut microbial antigens. The study of genetic variants associated with Crohn's disease has shed light on our understanding of disease pathophysiology. A large number of genetic variants identified in Crohn's disease are related to genes targeting microbial recognition and bacterial wall sensing, the most common being NOD2/CARD15 gene. This review will discuss the recent advance in our knowledge of genetic variants of this disease and how they influence the disease course and prognosis. Keywords: Crohn's disease, genetics, autophagy

  7. Splicing analysis of 14 BRCA1 missense variants classifies nine variants as pathogenic

    DEFF Research Database (Denmark)

    Ahlborn, Lise B; Dandanell, Mette; Steffensen, Ane Y;

    2015-01-01

    needed to classify whether these uncertain variants are pathogenic or benign. In this study, we investigated 14 BRCA1 variants by in silico splicing analysis and mini-gene splicing assay. All 14 alterations were missense variants located within the BRCT domain of BRCA1 and had previously been examined...... by functional analysis at the protein level. Results from a validated mini-gene splicing assay indicated that nine BRCA1 variants resulted in splicing aberrations leading to truncated transcripts and thus can be considered pathogenic (c.4987A>T/p.Met1663Leu, c.4988T>A/p.Met1663Lys, c.5072C>T/p.Thr1691Ile, c...... to have no or an uncertain effect on the protein level, whereas one variant (c.5072C>T/p.Thr1691Ile) were shown to have a strong effect on the protein level as well. In conclusion, our study emphasizes that in silico splicing prediction and mini-gene splicing analysis are important for the classification...

  8. Dose-Ranging Effects of Canagliflozin, a Sodium-Glucose Cotransporter 2 Inhibitor, as Add-On to Metformin in Subjects With Type 2 Diabetes

    Science.gov (United States)

    Rosenstock, Julio; Aggarwal, Naresh; Polidori, David; Zhao, Yue; Arbit, Deborah; Usiskin, Keith; Capuano, George; Canovatchel, William

    2012-01-01

    OBJECTIVE To evaluate the effects of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, in type 2 diabetes mellitus inadequately controlled with metformin monotherapy. RESEARCH DESIGN AND METHODS This was a double-blind, placebo-controlled, parallel-group, multicenter, dose-ranging study in 451 subjects randomized to canagliflozin 50, 100, 200, or 300 mg once daily (QD) or 300 mg twice daily (BID), sitagliptin 100 mg QD, or placebo. Primary end point was change in A1C from baseline through week 12. Secondary end points included change in fasting plasma glucose (FPG), body weight, and overnight urinary glucose-to-creatinine ratio. Safety and tolerability were also assessed. RESULTS Canagliflozin was associated with significant reductions in A1C from baseline (7.6–8.0%) to week 12: −0.79, −0.76, −0.70, −0.92, and −0.95% for canagliflozin 50, 100, 200, 300 mg QD and 300 mg BID, respectively, versus −0.22% for placebo (all P canagliflozin (3–8%) versus placebo and sitagliptin (2%). Urinary tract infections were reported without dose dependency in 3–9% of canagliflozin, 6% of placebo, and 2% of sitagliptin arms. Overall incidence of hypoglycemia was low. CONCLUSIONS Canagliflozin added onto metformin significantly improved glycemic control in type 2 diabetes and was associated with low incidence of hypoglycemia and significant weight loss. The safety/tolerability profile of canagliflozin was favorable except for increased frequency of genital infections in females. PMID:22492586

  9. Effect of canagliflozin, a sodium glucose co-transporter 2 inhibitor, on the pharmacokinetics of oral contraceptives, warfarin, and digoxin in healthy participants.

    Science.gov (United States)

    Devineni, Damayanthi; Manitpisitkul, Prasarn; Vaccaro, Nicole; Bernard, Apexa; Skee, Donna; Mamidi, Rao N V S; Tian, Hong; Weiner, Sveta; Stieltjes, Hans; Sha, Sue; Rothenberg, Paul

    2015-01-01

    Drug-drug interactions between canagliflozin, a sodium glucose co-transporter 2 inhibitor approved for the management of type-2 diabetes mellitus, and an oral contraceptive (OC), warfarin, and digoxin were evaluated in three phase 1 studies in healthy participants. All studies were open-label; study 1 included a fixed-sequence design, and studies 2 and 3 used a crossover design. Regimens were: study 1: OC (levonorgestrel (150 μg) + ethinyl estradiol (30 μg))/day (day 1), canagliflozin 200 mg/day (days 4 - 8), and canagliflozin with OC (day 9); study 2: canagliflozin 300 mg/day (days 1 - 12) with warfarin 30 mg/day (day 6) in period 1, and only warfarin 30 mg/day (day 1) in period 2, or vice versa; study 3: digoxin alone (0.5 mg/day (day 1) + 0.25 mg/day (days 2 - 7)) in period 1, and with canagliflozin 300 mg/day (days 1 - 7) in period 2, or vice versa. Pharmacokinetics (PK) were assessed at prespecified intervals; OC: days 1 and 9, canagliflozin: days 8 - 9 (study 1); warfarin: days 6 (period 1) and 1 (period 2) (study 2); and digoxin: days 5 - 7 (periods 1 and 2) (study 3). Warfarin's pharmacodynamics (PD; International Normalized Ratio (INR)) was assessed on days 6 (period 1) and 1 (period 2). Canagliflozin increased the plasma exposure of OC (maximum plasma concentration (Cmax): 22%, area under the curve (AUC): 6%) and digoxin (Cmax: 36%, AUC: 20%); but did not alter warfarin'€™s PK and PD. No clinically relevant safety findings (including hypoglycemia) were noted. Canagliflozin can be coadministered with OC, warfarin, or digoxin without dose adjustments. All treatments were well-tolerated.

  10. Pharmacodynamic effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor, from a randomized study in patients with type 2 diabetes.

    Science.gov (United States)

    Sha, Sue; Devineni, Damayanthi; Ghosh, Atalanta; Polidori, David; Hompesch, Marcus; Arnolds, Sabine; Morrow, Linda; Spitzer, Heike; Demarest, Keith; Rothenberg, Paul

    2014-01-01

    This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes. Patients (N = 116) discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in the United States and Germany, or canagliflozin 30 mg once daily or placebo at 1 study center in Korea, while maintaining an isocaloric diet for 2 weeks. On Days -1, 1, and 16, urinary glucose excretion (UGE), plasma glucose (PG), fasting PG (FPG), and insulin were measured. The renal threshold for glucose (RTG) was calculated from UGE, PG, and estimated glomerular filtration rate. Safety was evaluated based on adverse event (AE) reports, vital signs, electrocardiograms, clinical laboratory tests, and physical examinations. Canagliflozin increased UGE dose-dependently (,80-120 g/day with canagliflozin $100 mg), with increases maintained over the 14-day dosing period with each dose. Canagliflozin dose-dependently decreased RTG, with maximal reductions to ,4-5 mM (72-90 mg/dL). Canagliflozin also reduced FPG and 24-hour mean PG; glucose reductions were seen on Day 1 and maintained over 2 weeks. Plasma insulin reductions with canagliflozin were consistent with observed PG reductions. Canagliflozin also reduced body weight. AEs were transient, mild to moderate in intensity, and balanced across groups; 1 canagliflozin-treated female reported an episode of vaginal candidiasis. Canagliflozin did not cause hypoglycemia, consistent with the RTG values remaining above the hypoglycemia threshold. At Day 16, there were no clinically meaningful changes in urine volume, urine electrolyte excretion, renal function, or routine laboratory test values. Canagliflozin increased UGE and decreased RTG, leading to reductions

  11. Efficacy and safety of canagliflozin, an inhibitor of sodium-glucose cotransporter 2, when used in conjunction with insulin therapy in patients with type 2 diabetes.

    Science.gov (United States)

    Neal, Bruce; Perkovic, Vlado; de Zeeuw, Dick; Mahaffey, Kenneth W; Fulcher, Greg; Ways, Kirk; Desai, Mehul; Shaw, Wayne; Capuano, George; Alba, Maria; Jiang, Joel; Vercruysse, Frank; Meininger, Gary; Matthews, David

    2015-03-01

    There are limited data about the effects of sodium-glucose cotransporter 2 inhibitors when used with insulin. We report the efficacy and safety of canagliflozin in patients with type 2 diabetes using insulin. The CANagliflozin CardioVascular Assessment Study is a double-blind, placebo-controlled study that randomized participants to placebo, canagliflozin 100 mg, or canagliflozin 300 mg once daily, added to a range of therapies. The primary end point of this substudy was the change in HbA1c from baseline at 18 weeks among patients using insulin; 52-week effects were also examined. Individuals receiving insulin at baseline were randomized to receive placebo (n = 690), canagliflozin 100 mg (n = 692), or canagliflozin 300 mg (n = 690). These individuals were 66% male and had a median age of 63 years, mean HbA1c of 8.3% (67 mmol/mol), BMI of 33.1 kg/m(2), estimated glomerular filtration rate of 75 mL/min/1.73 m(2), fasting plasma glucose of 9.2 mmol/L, and a median daily insulin dose of 60 IU. Most individuals were using basal/bolus insulin. Reductions in HbA1c with canagliflozin 100 and 300 mg versus placebo were -0.62% (95% CI -0.69, -0.54; -6.8 mmol/mol [95% CI -7.5, -5.9]; P canagliflozin doses. Canagliflozin added to insulin therapy improved glycemic control and decreased body weight. There was a greater frequency of several anticipated side effects, although few led to discontinuation of treatment. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  12. Effects of rifampin, cyclosporine A, and probenecid on the pharmacokinetic profile of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in healthy participants.

    Science.gov (United States)

    Devineni, Damayanthi; Vaccaro, Nicole; Murphy, Joe; Curtin, Christopher; Mamidi, Rao N V S; Weiner, Sveta; Wang, Shean-Sheng; Ariyawansa, Jay; Stieltjes, Hans; Wajs, Ewa; Di Prospero, Nicholas A; Rothenberg, Paul

    2015-02-01

    Canagliflozin, a sodium-glucose co-transporter 2 inhibitor, approved for the treatment of type-2 diabetes mellitus (T2DM), is metabolized by uridine diphosphate-glucuronosyltransferases (UGT) 1A9 and UGT2B4, and is a substrate of P-glycoprotein (P-gp). Canagliflozin exposures may be affected by coadministration of drugs that induce (e.g., rifampin for UGT) or inhibit (e.g. probenecid for UGT; cyclosporine A for P-gp) these pathways. The primary objective of these three independent studies (single-center, open-label, fixed-sequence) was to evaluate the effects of rifampin (study 1), probenecid (study 2), and cyclosporine A (study 3) on the pharmacokinetics of canagliflozin in healthy participants. Participants received; in study 1: canagliflozin 300 mg (days 1 and 10), rifampin 600 mg (days 4-12); study 2: canagliflozin 300 mg (days 1-17), probenecid 500 mg twice daily (days 15-17); and study 3: canagliflozin 300 mg (days 1-8), cyclosporine A 400 mg (day 8). Pharmacokinetics were assessed at prespecified intervals on days 1 and 10 (study 1); on days 14 and 17 (study 2), and on days 2-8 (study 3). Rifampin decreased the maximum plasma canagliflozin concentration (Cmax) by 28% and its area under the curve (AUC) by 51%. Probenecid increased the Cmax by 13% and the AUC by 21%. Cyclosporine A increased the AUC by 23% but did not affect the Cmax. Coadministration of canagliflozin with rifampin, probenecid, and cyclosporine A was well-tolerated. No clinically meaningful interactions were observed for probenecid or cyclosporine A, while rifampin coadministration modestly reduced canagliflozin plasma concentrations and could necessitate an appropriate monitoring of glycemic control.

  13. Reactive Neurogenesis and Down-Regulation of the Potassium-Chloride Cotransporter KCC2 in the Cochlear Nuclei after Cochlear Deafferentation

    Science.gov (United States)

    Tighilet, Brahim; Dutheil, Sophie; Siponen, Marina I.; Noreña, Arnaud J.

    2016-01-01

    While many studies have been devoted to investigating the homeostatic plasticity triggered by cochlear hearing loss, the cellular and molecular mechanisms involved in these central changes remain elusive. In the present study, we investigated the possibility of reactive neurogenesis after unilateral cochlear nerve section in the cochlear nucleus (CN) of cats. We found a strong cell proliferation in all the CN sub-divisions ipsilateral to the lesion. Most of the newly generated cells survive up to 1 month after cochlear deafferentation in all cochlear nuclei (except the dorsal CN) and give rise to a variety of cell types, i.e., microglial cells, astrocytes, and neurons. Interestingly, many of the newborn neurons had an inhibitory (GABAergic) phenotype. This result is intriguing since sensory deafferentation is usually accompanied by enhanced excitation, consistent with a reduction in central inhibition. The membrane potential effect of GABA depends, however, on the intra-cellular chloride concentration, which is maintained at low levels in adults by the potassium chloride co-transporter KCC2. The KCC2 density on the plasma membrane of neurons was then assessed after cochlear deafferentation in the cochlear nuclei ipsilateral and contralateral to the lesion. Cochlear deafferentation is accompanied by a strong down-regulation of KCC2 ipsilateral to the lesion at 3 and 30 days post-lesion. This study suggests that reactive neurogenesis and down-regulation of KCC2 is part of the vast repertoire involved in homeostatic plasticity triggered by hearing loss. These central changes may also play a role in the generation of tinnitus and hyperacusis. PMID:27630564

  14. A novel and selective sodium-glucose cotransporter-2 inhibitor, tofogliflozin, improves glycaemic control and lowers body weight in patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Ikeda, S; Takano, Y; Cynshi, O; Tanaka, R; Christ, A D; Boerlin, V; Beyer, U; Beck, A; Ciorciaro, C; Meyer, M; Kadowaki, T

    2015-10-01

    To assess the efficacy, safety and tolerability of different doses of tofogliflozin, a novel, highly selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes mellitus (T2DM). In a 12-week, multicentre, multinational, randomized, double-blind, parallel-group, placebo-controlled, dose-finding study, patients with inadequate glycaemic control from diet and exercise alone, or from diet and exercise plus a stable dose of metformin, were randomized to one of five doses of tofogliflozin (2.5, 5, 10, 20, or 40 mg) or placebo. The primary efficacy endpoint was absolute change at week 12 from baseline in glycated haemoglobin (HbA1c), minus the change in the placebo group. Statistically significant dose-dependent reductions in HbA1c were shown in all treated groups except the 2.5-mg dose group, with a maximum reduction of 0.56% (placebo-subtracted) at the 40-mg dose, along with increased urinary glucose excretion. Metformin treatment had no substantial influence on tofogliflozin efficacy. Dose-dependent reductions in fasting plasma glucose and body weight were observed, and glucose intolerance was improved, with a trend towards blood pressure reduction. Slight increases were observed for mean ketone bodies with no abnormal change in ketone body ratio. No deaths or treatment-related serious adverse events were reported. The incidence of adverse events was similar in the placebo (37.9%) to that in the tofogliflozin group (35.9-46.3%). Withdrawal because of adverse events was rare (≤2 patients per treatment group), with similar rates of withdrawal in the placebo and tofogliflozin groups. A once-daily dose of tofogliflozin for 12 weeks was an effective, safe and well-tolerated treatment for T2DM. © 2015 John Wiley & Sons Ltd.

  15. Canagliflozin, a sodium glucose cotransporter 2 inhibitor, attenuates obesity-induced inflammation in the nodose ganglion, hypothalamus, and skeletal muscle of mice.

    Science.gov (United States)

    Naznin, Farhana; Sakoda, Hideyuki; Okada, Tadashi; Tsubouchi, Hironobu; Waise, T M Zaved; Arakawa, Kenji; Nakazato, Masamitsu

    2017-01-05

    Chronic inflammation in systemic organs, such as adipose tissue, nodose ganglion, hypothalamus, and skeletal muscles, is closely associated with obesity and diabetes mellitus. Because sodium glucose cotransporter 2 (SGLT2) inhibitors exert both anti-diabetic and anti-obesity effects by promoting urinary excretion of glucose and subsequent caloric loss, we investigated the effect of canagliflozin, an SGLT2 inhibitor, on obesity-induced inflammation in neural tissues and skeletal muscles of mice. High-fat diet (HFD)-fed male C57BL/6J mice were treated with canagliflozin for 8 weeks. Canagliflozin attenuated the HFD-mediated increases in body weight, liver weight, and visceral and subcutaneous fat weight. Additionally, canagliflozin decreased blood glucose as well as the fat, triglyceride, and glycogen contents of the liver. Along with these metabolic corrections, canagliflozin attenuated the increases in the mRNA levels of the proinflammatory biomarkers Iba1 and Il6 and the number of macrophages/microglia in the nodose ganglion and hypothalamus. In the skeletal muscle of HFD-fed obese mice, canagliflozin decreased inflammatory cytokine levels, macrophage accumulation, and the mRNA level of the specific atrophic factor atrogin-1. Canagliflozin also increased the mRNA level of insulin-like growth factor 1, protected against muscle mass loss, and restored the contractile force of muscle. These findings suggested that SGLT2 inhibition disrupts the vicious cycle of obesity and inflammation, not only by promoting caloric loss, but also by suppression of obesity-related inflammation in both the nervous system and skeletal muscle.

  16. BDNF regulates spontaneous correlated activity at early developmental stages by increasing synaptogenesis and expression of the K+/Cl- co-transporter KCC2.

    Science.gov (United States)

    Aguado, Fernando; Carmona, Maria A; Pozas, Esther; Aguiló, Agustín; Martínez-Guijarro, Francisco J; Alcantara, Soledad; Borrell, Victor; Yuste, Rafael; Ibañez, Carlos F; Soriano, Eduardo

    2003-04-01

    Spontaneous neural activity is a basic property of the developing brain, which regulates key developmental processes, including migration, neural differentiation and formation and refinement of connections. The mechanisms regulating spontaneous activity are not known. By using transgenic embryos that overexpress BDNF under the control of the nestin promoter, we show here that BDNF controls the emergence and robustness of spontaneous activity in embryonic hippocampal slices. Further, BDNF dramatically increases spontaneous co-active network activity, which is believed to synchronize gene expression and synaptogenesis in vast numbers of neurons. In fact, BDNF raises the spontaneous activity of E18 hippocampal neurons to levels that are typical of postnatal slices. We also show that BDNF overexpression increases the number of synapses at much earlier stages (E18) than those reported previously. Most of these synapses were GABAergic, and GABAergic interneurons showed hypertrophy and a 3-fold increase in GAD expression. Interestingly, whereas BDNF does not alter the expression of GABA and glutamate ionotropic receptors, it does raise the expression of the recently cloned K(+)/Cl(-) KCC2 co-transporter, which is responsible for the conversion of GABA responses from depolarizing to inhibitory, through the control of the Cl(-) potential. Together, results indicate that both the presynaptic and postsynaptic machineries of GABAergic circuits may be essential targets of BDNF actions to control spontaneous activity. The data indicate that BDNF is a potent regulator of spontaneous activity and co-active networks, which is a new level of regulation of neurotrophins. Given that BDNF itself is regulated by neuronal activity, we suggest that BDNF acts as a homeostatic factor controlling the emergence, complexity and networking properties of spontaneous networks.

  17. Combination Therapy with a Sodium-Glucose Cotransporter 2 Inhibitor and a Dipeptidyl Peptidase-4 Inhibitor Additively Suppresses Macrophage Foam Cell Formation and Atherosclerosis in Diabetic Mice

    Science.gov (United States)

    Hiromura, Munenori; Mori, Yusaku; Kohashi, Kyoko; Kushima, Hideki; Ohara, Makoto; Watanabe, Takuya; Andersson, Olov

    2017-01-01

    Dipeptidyl peptidase-4 inhibitors (DPP-4is), in addition to their antihyperglycemic roles, have antiatherosclerotic effects. We reported that sodium-glucose cotransporter 2 inhibitors (SGLT2is) suppress atherosclerosis in a glucose-dependent manner in diabetic mice. Here, we investigated the effects of combination therapy with SGLT2i and DPP-4i on atherosclerosis in diabetic mice. SGLT2i (ipragliflozin, 1.0 mg/kg/day) and DPP-4i (alogliptin, 8.0 mg/kg/day), either alone or in combination, were administered to db/db mice or streptozotocin-induced diabetic apolipoprotein E-null (Apoe−/−) mice. Ipragliflozin and alogliptin monotherapies improved glucose intolerance; however, combination therapy did not show further improvement. The foam cell formation of peritoneal macrophages was suppressed by both the ipragliflozin and alogliptin monotherapies and was further enhanced by combination therapy. Although foam cell formation was closely associated with HbA1c levels in all groups, DPP-4i alone or the combination group showed further suppression of foam cell formation compared with the control or SGLT2i group at corresponding HbA1c levels. Both ipragliflozin and alogliptin monotherapies decreased scavenger receptors and increased cholesterol efflux regulatory genes in peritoneal macrophages, and combination therapy showed additive changes. In diabetic Apoe−/− mice, combination therapy showed the greatest suppression of plaque volume in the aortic root. In conclusion, combination therapy with SGLT2i and DPP4i synergistically suppresses macrophage foam cell formation and atherosclerosis in diabetic mice.

  18. Fructose-1,6-diphosphate protects against epileptogenesis by modifying cation-chloride co-transporters in a model of amygdaloid-kindling temporal epilepticus.

    Science.gov (United States)

    Ding, Yao; Wang, Shan; Jiang, Yan; Yang, Yi; Zhang, Manman; Guo, Yi; Wang, Shuang; Ding, Mei-ping

    2013-11-20

    Fructose-1,6-diphosphate (FDP) shifts the metabolism of glucose from glycolysis to the pentose phosphate pathway and has anticonvulsant activity in several acute seizure animal models. In the present study, we investigated the anti-epileptogenic effects of FDP in an amygdaloid-kindling seizure model, which is an animal model of the most common form of human temporal lobe epilepsy. We found that 1.0 g/kg FDP slowed seizure progression and shortened the corresponding after-discharge duration (ADD). FDP increased the number of stimulations needed to reach seizure stages 2-5 and prolonged the cumulative ADD prior to reaching stages 3-5. It also shortened staying days and cumulative ADD in stages 4-5. However, it demonstrated no significant protective effect when administered after the animals were fully kindled. In hippocampal neurons, cation-chloride co-transporters (CCCs) are suggested to play interesting roles in epilepsy by modulating γ-aminobutyric acid (GABA)ergic activity through controlling GABAA receptor-mediated reversal potential. We examined the potential link between FDP and the hippocampal expression of two main members of the CCCs: the neuron-specific K(+)-Cl(-)co-transporter 2 (KCC2) and Na(+)-K(+)-Cl(-)co-transporter 1 (NKCC1). FDP inhibited the kindling-induced downregulation of KCC2 expression and decreased NKCC1 expression during the kindling session. Taken together, our data reveal that FDP may have protective activity against epileptogenesis, from partial to generalized tonic-clonic seizures. Furthermore, our findings suggest that the FDP-induced imbalance between KCC2 and NKCC1 expression may be involved in the neuroprotective effect.

  19. The sodium glucose cotransporter type 2 inhibitor empagliflozin preserves β-cell mass and restores glucose homeostasis in the male zucker diabetic fatty rat.

    Science.gov (United States)

    Hansen, Henrik H; Jelsing, Jacob; Hansen, Carl Frederik; Hansen, Gitte; Vrang, Niels; Mark, Michael; Klein, Thomas; Mayoux, Eric

    2014-09-01

    Type 2 diabetes is characterized by impaired β-cell function associated with progressive reduction of insulin secretion and β-cell mass. Evidently, there is an unmet need for treatments with greater sustainability in β-cell protection and antidiabetic efficacy. Through an insulin and β cell-independent mechanism, empagliflozin, a specific sodium glucose cotransporter type 2 (SGLT-2) inhibitor, may potentially provide longer efficacy. This study compared the antidiabetic durability of empagliflozin treatment (10 mg/kg p.o.) against glibenclamide (3 mg/kg p.o.) and liraglutide (0.2 mg/kg s.c.) on deficient glucose homeostasis and β-cell function in Zucker diabetic fatty (ZDF) rats. Empagliflozin and liraglutide led to marked improvements in fed glucose and hemoglobin A1c levels, as well as impeding a progressive decline in insulin levels. In contrast, glibenclamide was ineffective. Whereas the effects of liraglutide were less pronounced at week 8 of treatment compared with week 4, those of empagliflozin remained stable throughout the study period. Similarly, empagliflozin improved glucose tolerance and preserved insulin secretion after both 4 and 8 weeks of treatment. These effects were reflected by less reduction in β-cell mass with empagliflozin or liraglutide at week 4, whereas only empagliflozin showed β-cell sparing effects also at week 8. Although this study cannot be used to dissociate the absolute antidiabetic efficacy among the different mechanisms of drug action, the study demonstrates that empagliflozin exerts a more sustained improvement of glucose homeostasis and β-cell protection in the ZDF rat. In comparison with other type 2 diabetic treatments, SGLT-2 inhibitors may through insulin-independent pathways thus enhance durability of β-cell protection and antidiabetic efficacy.

  20. Activated PKCδ and PKCϵ Inhibit Epithelial Chloride Secretion Response to cAMP via Inducing Internalization of the Na+-K+-2Cl− Cotransporter NKCC1*

    Science.gov (United States)

    Tang, Jun; Bouyer, Patrice; Mykoniatis, Andreas; Buschmann, Mary; Matlin, Karl S.; Matthews, Jeffrey B.

    2010-01-01

    The basolateral Na+-K+-2Cl− cotransporter (NKCC1) is a key determinant of transepithelial chloride secretion and dysregulation of chloride secretion is a common feature of many diseases including secretory diarrhea. We have previously shown that activation of protein kinase C (PKC) markedly reduces transepithelial chloride secretion in human colonic T84 cells, which correlates with both functional inhibition and loss of the NKCC1 surface expression. In the present study, we defined the specific roles of PKC isoforms in regulating epithelial NKCC1 and chloride secretion utilizing adenoviral vectors that express shRNAs targeting human PKC isoforms (α, δ, ϵ) (shPKCs) or LacZ (shLacZ, non-targeting control). After 72 h of adenoviral transduction, protein levels of the PKC isoforms in shPKCs-T84 cells were decreased by ∼90% compared with the shLacZ-control. Activation of PKCs by phorbol 12-myristate 13-acetate (PMA) caused a redistribution of NKCC1 immunostaining from the basolateral membrane to intracellular vesicles in both shLacZ- and shPKCα-T84 cells, whereas the effect of PMA was not observed in shPKCδ- and shPKCϵ- cells. These results were further confirmed by basolateral surface biotinylation. Furthermore, activation of PKCs by PMA inhibited cAMP-stimulated chloride secretion in the uninfected, shLacZ- and shPKCα-T84 monolayers, but the inhibitory effect was significantly attenuated in shPKCδ- and shPKCϵ-T84 monolayers. In conclusion, the activated novel isoforms PKCδ or PKCϵ, but not the conventional isoform PKCα, inhibits transepithelial chloride secretion through inducing internalization of the basolateral surface NKCC1. Our study reveals that the novel PKC isoform-regulated NKCC1 surface expression plays an important role in the regulation of chloride secretion. PMID:20732874

  1. Phorbol 12-myristate 13-acetate-induced endocytosis of the Na-K-2Cl cotransporter in MDCK cells is associated with a clathrin-dependent pathway.

    Science.gov (United States)

    Mykoniatis, Andreas; Shen, Le; Fedor-Chaiken, Mary; Tang, Jun; Tang, Xu; Worrell, Roger T; Delpire, Eric; Turner, Jerrold R; Matlin, Karl S; Bouyer, Patrice; Matthews, Jeffrey B

    2010-01-01

    In secretory epithelial cells, the basolateral Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) plays a major role in salt and fluid secretion. Our laboratory has identified NKCC1 surface expression as an important regulatory mechanism for Cl(-) secretion in the colonic crypt cell line T84, a process also present in native human colonic crypts. We previously showed that activation of protein kinase C (PKC) by carbachol and phorbol 12-myristate 13-acetate (PMA) decreases NKCC1 surface expression in T84 cells. However, the specific endocytic entry pathway has not been defined. We used a Madin-Darby canine kidney (MDCK) cell line stably transfected with enhanced green fluorescent protein (EGFP)-NKCC1 to map NKCC1 entry during PMA exposure. At given times, we fixed and stained the cells with specific markers (e.g., dynamin II, clathrin heavy chain, and caveolin-1). We also used chlorpromazine, methyl-beta-cyclodextrin, amiloride, and dynasore, blockers of the clathrin, caveolin, and macropinocytosis pathways and the vesicle "pinchase" dynamin, respectively. We found that PMA caused dose- and time-dependent NKCC1 endocytosis. After 2.5 min of PMA exposure, approximately 80% of EGFP-NKCC1 endocytic vesicles colocalized with clathrin and approximately 40% colocalized with dynamin II and with the transferrin receptor, the uptake of which is also mediated by clathrin-coated vesicles. We did not observe significant colocalization of EGFP-NKCC1 endocytic vesicles with caveolin-1, a marker of the caveolae-mediated endocytic pathway. We quantified the effect of each inhibitor on PMA-induced EGFP-NKCC1 endocytosis and found that only chlorpromazine and dynasore caused significant inhibition compared with the untreated control (61% and 25%, respectively, at 2.5 min). Together, these results strongly support the conclusion that PMA-stimulated NKCC1 endocytosis is associated with a clathrin pathway.

  2. Site-directed mutation of arginine 282 to glutamate uncouples the movement of peptides and protons by the rabbit proton-peptide cotransporter PepT1.

    Science.gov (United States)

    Meredith, David

    2004-04-16

    A conserved positive residue in the seventh transmembrane domain of the mammalian proton-coupled di- and tripeptide transporter PepT1 has been shown by site-directed mutagenesis to be a key residue for protein function. Substitution of arginine 282 with a glutamate residue (R282E-PepT1) gave a protein at the plasma membrane of Xenopus laevis oocytes that was able to transport the non-hydrolyzable dipeptide [3H]d-Phe-l-Gln, although unlike the wild type, the rate of transport by R282E-PepT1 was independent of the extracellular pH level, and the substrate could not be accumulated above equilibrium. The binding affinity of the mutant transport protein was unchanged from the wild type. Thus, R282E-Pept1 appears to have been changed from a proton-driven to a facilitated transporter for peptides. In addition, peptide transport by R282E-PepT1 still induced depolarization as measured by microelectrode recordings of membrane potential. A more detailed study by two-electrode voltage clamping revealed that R282E-PepT1 behaved as a peptide-gated non-selective cation channel with the ion selectivity series lithium > sodium > N-methyl-d-glucamine at pH 7.4. There was also a proton conductance (comparing pH 7.4 and 8.4), and at pH 5.5 the predominant conductance was for potassium ions. Therefore, it can be concluded that changing arginine 282 to a glutamate not only uncouples the cotransport of protons and peptides of the wild-type PepT1 but also creates a peptide-gated cation channel in the protein.

  3. Interactions between Na+ channels and Na+-HCO3- cotransporters in the freshwater fish gill MR cell: a model for transepithelial Na+ uptake.

    Science.gov (United States)

    Parks, Scott K; Tresguerres, Martin; Goss, Greg G

    2007-02-01

    Isolated mitochondria-rich (MR) cells from the rainbow trout gill epithelium were subjected to intracellular pH (pH(i)) imaging with the pH-sensitive dye BCECF-AM. MR cells were categorized into two distinct functional subtypes based on their ability to recover pH(i) from an NH(4)Cl-induced acidification in the absence of Na(+). An apparent link between resting pH(i) and Na(+)-independent pH(i) recovery was made. We observed a unique pH(i) acidification event that was induced by extracellular Na(+) addition. This further classified the mixed MR cell population into two functional subtypes: the majority of cells (77%) demonstrated the Na(+)-induced pH(i) acidification, whereas the minority (23%) demonstrated an alkalinization of pH(i) under the same circumstances. The focus of this study was placed on the Na(+)-induced acidification and pharmacological analysis via the use of amiloride and phenamil, which revealed that Na(+) uptake was responsible for the intracellular acidification. Further experiments revealed that pH(i) acidification could be abolished when Na(+) was allowed entry into the cell, but the activity of an electrogenic Na(+)-HCO(3)(-) cotransporter (NBC) was inhibited by DIDS. The electrogenic NBC activity was supported by a DIDS-sensitive, Na(+)-induced membrane potential depolarization as observed via imaging of the voltage-sensitive dye bis-oxonol. We also demonstrated NBC immunoreactivity via Western blotting and immunohistochemistry in gill tissue. We propose a model for transepithelial Na(+) uptake occurring via an apical Na(+) channel linked to a basolateral, electrogenic NBC in one subpopulation of MR cells.

  4. Effect of vasopressin on Na(+)-K(+)-2Cl(-) cotransporter (NKCC) and the signaling mechanisms on the murine late distal colon.

    Science.gov (United States)

    Xue, Hong; Tang, Xudong

    2016-01-15

    It has been demonstrated that the antidiuretic hormone vasopressin is able to regulate the expression of Na-K-Cl cotransporters (NKCC1 and NKCC2) in the kidney. The present study investigated the effects of long- and short-term administration of vasopressin on NKCC and the possible signaling mechanism of vasopressin in the mouse distal colon using the siRNA, real-time PCR, western blotting and Ussing chambers method. The results showed the presence of NKCC2 expression in the colon, which was verified with a siRNA technique. The mRNA and protein expression level of NKCC2 significantly increased by about 40% and 90% respectively in response to restricting water intake to 1ml/day/20g for 7 days. In contrast, the NKCC1 expression level was unchanged in the colon. To determine the short-term activation of NKCC2 by vasopressin in vitro, we found that the administration of vasopressin caused a 3-fold increase in mouse colon NKCC2 phosphorylation, which was detected with phosphospecific antibody R5. In addition, the Ussing chamber results showed that NKCC2, cAMP and Ca(2+) signaling pathway may be involved in the vasopressin-induced response. Further, adenylate cyclase inhibitor MDL-12330A and PKA inhibitor H89 and Ca(2+) chelator BAPTA-AM reversed the vasopressin induced NKCC2 phosphorylation level increase by about 35%, 28% and 42% respectively suggesting vasopressin stimulate NKCC2 phosphorylation increase mediated by cAMP-PKA and Ca(2+) signaling in the colon. Collectively, these data suggest that the expression and phosphorylation of NKCC2 are increased in the colon by vasopressin stimulation, in association with enhanced activity of the vasopressin/cAMP and Ca(2+) pathways.

  5. Reactive neurogenesis and down-regulation of the potassium-chloride cotransporter KCC2 in the cochlear nuclei after cochlear deafferentation

    Directory of Open Access Journals (Sweden)

    Brahim Tighilet

    2016-08-01

    Full Text Available While many studies have been devoted to investigating the homeostatic plasticity triggered by cochlear hearing loss, the cellular and molecular mechanisms involved in these central changes remain elusive. In the present study, we investigated the possibility of reactive neurogenesis after unilateral cochlear nerve section in the cochlear nucleus of cats. We found a strong cell proliferation in all the cochlear nucleus sub-divisions ipsilateral to the lesion. Most of the newly generated cells survive up to one month after cochlear deafferentation in all cochlear nuclei (except the dorsal cochlear nucleus and give rise to a variety of cell types, i.e. microglial cells, astrocytes and neurons. Interestingly, many of the newborn neurons had an inhibitory (GABAergic phenotype. This result is intriguing since sensory deafferentation is usually accompanied by enhanced excitation, consistent with a reduction in central inhibition. The membrane potential effect of GABA depends, however, on the intra-cellular chloride concentration, which is maintained at low levels in adults by the potassium chloride co-transporter KCC2. The KCC2 density on the plasma membrane of neurons was then assessed after cochlear deafferentation in the cochlear nuclei ipsilateral and contralateral to the lesion. Cochlear deafferentation is accompanied by a strong down-regulation of KCC2 ipsilateral to the lesion at 3 and 30 days post-lesion. This study suggests that reactive neurogenesis and downregulation of KCC2 is part of the vast repertoire involved in homeostatic plasticity triggered by hearing loss. These central changes may also play a role in the generation of tinnitus and hyperacusis.

  6. Antidiuretic effect of hydrochlorothiazide in lithium-induced nephrogenic diabetes insipidus is associated with upregulation of aquaporin-2, Na-Cl co-transporter, and epithelial sodium channel.

    Science.gov (United States)

    Kim, Gheun-Ho; Lee, Jay Wook; Oh, Yun Kyu; Chang, Hye Ryun; Joo, Kwon Wook; Na, Ki Young; Earm, Jae-Ho; Knepper, Mark A; Han, Jin Suk

    2004-11-01

    Thiazides have been used in patients with nephrogenic diabetes insipidus (NDI) to decrease urine volume, but the mechanism by which it produces the paradoxic antidiuretic effect remains unclear. Previous studies have reported that downregulation of aquaporin-2 (AQP2) is important for the development of lithium-induced (Li-induced) polyuria and that hydrochlorothiazide (HCTZ) increases renal papillary osmolality and Na(+) concentration in Brattleboro rats. For elucidating the molecular basis of the antidiuretic action of HCTZ in diabetes insipidus, whether administration of HCTZ may affect the expression of AQP2 and major renal Na(+) transporters in Li-induced NDI rats was investigated, using semiquantitative immunoblotting and immunohistochemistry. After feeding male Sprague-Dawley rats Li chloride-containing rat diet for 4 wk, HCTZ or vehicle was infused subcutaneously via osmotic minipump. Urine output was significantly decreased by HCTZ treatment, whereas it was not changed in vehicle-treated rats. Urine osmolality was also higher in HCTZ-treated rats than in vehicle-treated rats. Semiquantitative immunoblotting using whole-kidney homogenates revealed that HCTZ treatment caused a significant partial recovery in AQP2 abundance from Li-induced downregulation. AQP2 immunohistochemistry showed compatible findings with the immunoblot results in both cortex and medulla. The abundances of thiazide-sensitive NaCl co-transporter and alpha-epithelial sodium channel were increased by HCTZ treatment. Notably, HCTZ treatment induced a shift in molecular weight of gamma-epithelial sodium channel from 85 to 70 kD, consistent with previously demonstrated aldosterone stimulation. The upregulation of AQP2 and distal renal Na(+) transporters in response to HCTZ treatment may account for the antidiuretic action of HCTZ in NDI.

  7. Dietary salt modulates the sodium chloride cotransporter expression likely through an aldosterone-mediated WNK4-ERK1/2 signaling pathway.

    Science.gov (United States)

    Lai, Lingyun; Feng, Xiuyan; Liu, Defeng; Chen, Jing; Zhang, Yiqian; Niu, Bowen; Gu, Yong; Cai, Hui

    2012-03-01

    WNK is a serine/threonine kinase. Mutation in WNK1 or WNK4 kinase results in pseudohypoaldosteronism type II (PHA II) featuring hypertension, hyperkalemia and metabolic acidosis. Sodium chloride cotransporter (NCC) is known to be regulated by phosphorylation and trafficking. Dietary salt and hormonal stimulation, such as aldosterone, also affect the regulation of NCC. We have previously reported that WNK4 inhibits NCC protein expression. To determine whether dietary salt affects NCC abundance through WNK4-mediated mechanism, we investigated the effects of dietary salt change with or without aldosterone infusion (1 mg/kg/day) on NCC and WNK4 expression in rats. We found that high-salt (HS, 4% NaCl) diet significantly inhibits NCC mRNA expression and protein abundance while enhancing WNK4 mRNA and protein expression, whereas low-salt (LS, 0.07% NaCl) diet increases NCC mRNA expression and protein abundance while reducing WNK4 expression. We also found that aldosterone infusion in HS-fed rats increases NCC mRNA expression and protein abundance, but decreases WNK4 expression. Administration with spironolactone (0.1 g/kg/day) in LS-fed rats decreases NCC mRNA expression and protein abundance while increasing WNK4 expression. We further showed that ERK1/2 phosphorylation was increased in HS-fed rats, but decreased in LS-fed rats. In HEK293 cells, over-expressed WNK4 increases ERK1/2 phosphorylation, whereas knockdown of WNK4 expression decreases ERK1/2 phosphorylation. Aldosterone treatment for 3 h decreases ERK1/2 phosphorylation. These data suggest that dietary salt change affects NCC protein abundance in an aldosterone-dependent mechanism likely via the WNK4-ERK1/2-mediated pathway.

  8. Drug-drug interactions with sodium-glucose cotransporters type 2 (SGLT2) inhibitors, new oral glucose-lowering agents for the management of type 2 diabetes mellitus.

    Science.gov (United States)

    Scheen, André J

    2014-04-01

    Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. They are proposed as a novel approach for the management of type 2 diabetes mellitus. They have proven their efficacy in reducing glycated haemoglobin, without inducing hypoglycaemia, as monotherapy or in combination with various other glucose-lowering agents, with the add-on value of promoting some weight loss and lowering arterial blood pressure. As they may be used concomitantly with many other drugs, we review the potential drug-drug interactions (DDIs) regarding the three leaders in the class (dapagliglozin, canagliflozin and empagliflozin). Most of the available studies were performed in healthy volunteers and have assessed the pharmacokinetic interferences with a single administration of the SGLT2 inhibitor. The exposure [assessed by peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC)] to each SGLT2 inhibitor tested was not significantly influenced by the concomitant administration of other glucose-lowering agents or cardiovascular agents commonly used in patients with type 2 diabetes. Reciprocally, these medications did not influence the pharmacokinetic parameters of dapagliflozin, canagliflozin or empagliflozin. Some modest changes were not considered as clinically relevant. However, drugs that could specifically interfere with the metabolic pathways of SGLT2 inhibitors [rifampicin, inhibitors or inducers of uridine diphosphate-glucuronosyltransferase (UGT)] may result in significant changes in the exposure of SGLT2 inhibitors, as shown for dapagliflozin and canagliflozin. Potential DDIs in patients with type 2 diabetes receiving chronic treatment with an SGLT2 inhibitor deserve further attention, especially in individuals treated with several medications or in more fragile patients with hepatic and/or renal impairment.

  9. Diabetes and kidney disease: the role of sodium-glucose cotransporter-2 (SGLT-2) and SGLT-2 inhibitors in modifying disease outcomes.

    Science.gov (United States)

    Mende, Christian W

    2017-03-01

    Patients with type 2 diabetes (T2D) often have coexisting chronic kidney disease (CKD). However, healthy renal function is crucial in maintaining glucose homeostasis, assuring that almost all of the filtered glucose is reabsorbed by the sodium glucose cotransporters (SGLTs) SGLT-1 and SGLT-2. In diabetes, an increased amount of glucose is filtered by the kidneys and SGLT-2 is upregulated, leading to increased glucose absorption and worsening hyperglycemia. Prolonged hyperglycemia contributes to the development of CKD by inducing metabolic and hemodynamic changes in the kidneys. Due to the importance of SGLT-2 in regulating glucose levels, investigation into SGLT-2 inhibitors was initiated as a glucose-dependent mechanism to control hyperglycemia, and there are three agents currently approved for use in the United States: dapagliflozin, canagliflozin, and empagliflozin. SGLT-2 inhibitors have been shown to reduce glycated hemoglobin (A1C), weight, and blood pressure, which not only affects glycemic control, but may also help slow the progression of renal disease by impacting the underlying mechanisms of kidney injury. In addition, SGLT-2 inhibitors have shown reductions in albuminuria, uric acid, and an increase in magnesium. Caution is advised when prescribing SGLT-2 inhibitors to patients with moderately impaired renal function and those at risk for volume depletion and hypotension. Published data on slowing of the development, as well as progression of CKD, is a hopeful indicator for the possible renal protection potential of this drug class. This narrative review provides an in-depth discussion of the interplay between diabetes, SGLT-2 inhibitors, and factors that affect kidney function.

  10. Sodium-glucose co-transporter-2 inhibitors and dipeptidyl peptidase-4 inhibitors combination therapy in type 2 diabetes: A systematic review of current evidence

    Directory of Open Access Journals (Sweden)

    Awadhesh Kumar Singh

    2016-01-01

    Full Text Available As type 2 diabetes mellitus (T2DM is a chronic and progressive disease with multiple pathophysiologic defects, no single anti-diabetic agent can tackle all these multi-factorial pathways. Consequently, multiple agents working through the different mechanisms will be required for the optimal glycemic control. Moreover, the combination therapies of different anti-diabetic agents may complement their actions and possibly act synergistic. Furthermore, these combinations could possess the additional properties to counter their undesired physiological compensatory response. Sodium-glucose co-transporter-2 inhibitors (SGLT-2I are newly emerging class of drugs, with a great potential to reduce glucose effectively with an additional quality of lowering cardiovascular events as demonstrated very recently by one of the agents of this class. However, increase in endogenous glucose production (EGP from the liver, either due to the increase in glucagon or compensatory response to glucosuria can offset the glucose-lowering potential of SGLT-2I. Interestingly, another class of drugs such as dipeptidyl peptidase-4 inhibitors (DPP-4I effectively decrease glucagon and reduce EGP. In light of these findings, combination therapies with SGLT-2I and DPP-4I are particularly appealing and are expected to produce a synergistic effect. Preclinical studies of combination therapies with DPP-4I and SGLT-2I have already demonstrated a significant lowering of hemoglobin A1c potential and human studies also find no drug-drug interaction between these agents. This article aims to systematically review the efficacy and safety of combination therapy of SGLT-2I and DPP-4I in T2DM.

  11. Essential role for NHERF in cAMP-mediated inhibition of the Na+-HCO3- co-transporter in BSC-1 cells.

    Science.gov (United States)

    Weinman, E J; Evangelista, C M; Steplock, D; Liu, M Z; Shenolikar, S; Bernardo, A

    2001-11-01

    Prior studies have indicated a requirement for the PDZ domain-containing protein, Na(+)/H(+) Exchanger Regulatory Factor (NHERF), for protein kinase A (PKA)-mediated inhibition of the renal basolateral Na(+)-HCO(3)(-) co-transporter (NBC). The present studies explore the potential mechanisms by which NHERF transduces cAMP signals to inhibit NBC. In BSC-1 cells, cells that express NBC but lack NHERF, 8-bromo-cAMP (100 microm for 15 min) failed to inhibit transport until wild-type mNHERF-(1-355) was expressed. mNHERF-(116-355) containing PDZ II and C-terminal ezrin-binding sequences or a mutant unphosphorylated form of rabbit NHERF effectively transduced the cAMP signals that inhibited NBC. By contrast, mNHERF-(1-126) encompassing N-terminal PDZ I and mNHERF-(1-325), which lacks ezrin-binding, failed to support cAMP inhibition of NBC activity. NBC and NHERF did not associate with each other in yeast two-hybrid or co-immunoprecipitation assays, and confocal microscopy indicated distinct subcellular localization of the two proteins. NBC was phosphorylated in BSC-1 cells, but its phosphorylation was not increased by cAMP nor was immunoprecipitated NBC phosphorylated by PKA in vitro. Acute exposure of mNHERF-(1-355)-expressing BSC-1 cells to cAMP did not change cell surface expression of NBC. Although these results established an essential role for NHERF in cAMP-mediated inhibition of NBC in BSC-1 cells, they also suggest a novel mechanism for NHERF-mediated signal transduction distinct from that previously characterized from studies of other NHERF targets.

  12. Thiazide-sensitive Na+ -Cl- cotransporter (NCC) gene inactivation results in increased duodenal Ca2+ absorption, enhanced osteoblast differentiation and elevated bone mineral density.

    Science.gov (United States)

    Hsu, Yu-Juei; Yang, Sung-Sen; Cheng, Chih-Jen; Liu, Shu-Ting; Huang, Shih-Ming; Chau, Tom; Chu, Pauling; Salter, Donald M; Lee, Herng-Sheng; Lin, Shih-Hua

    2015-01-01

    Inactivation of the thiazide-sensitive sodium chloride cotransporter (NCC) due to genetic mutations in Gitelman's syndrome (GS) or pharmacological inhibition with thiazide diuretics causes hypocalciuria and increased bone mineral density (BMD) with unclear extrarenal calcium (Ca(2+) ) regulation. We investigated intestinal Ca(2+) absorption and bone Ca(2+) metabolism in nonsense Ncc Ser707X (S707X) homozygous knockin mice (Ncc(S707X/S707X) mice). Compared to wild-type and heterozygous knockin littermates, Ncc(S707X/S707X) mice had increased intestinal absorption of (45) Ca(2+) and expression of the active Ca(2+) transport machinery (transient receptor potential vanilloid 6, calbindin-D9K , and plasma membrane Ca(2+) ATPase isoform 1b). Ncc(S707X/S707X) mice had also significantly increased Ca(2+) content accompanied by greater mineral apposition rate (MAR) in their femurs and higher trabecular bone volume, cortical bone thickness, and BMD determined by μCT. Their osteoblast differentiation markers, such as bone alkaline phosphatase, procollagen I, osteocalcin, and osterix, were also significantly increased while osteoclast activity was unaffected. Analysis of marrow-derived bone cells, either treated with thiazide or directly cultured from Ncc S707X knockin mice, showed that the differentiation of osteoblasts was associated with increased phosphorylation of mechanical stress-induced focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). In conclusion, NCC inhibition stimulates duodenal Ca(2+) absorption as well as osteoblast differentiation and bone Ca(2+) storage, possibly through a FAK/ERK dependent mechanism. © 2014 American Society for Bone and Mineral Research.

  13. P2Y2 receptor activation inhibits the expression of the sodium-chloride cotransporter NCC in distal convoluted tubule cells.

    Science.gov (United States)

    Gailly, P; Szutkowska, M; Olinger, E; Debaix, H; Seghers, F; Janas, S; Vallon, V; Devuyst, O

    2014-11-01

    Luminal nucleotide stimulation is known to reduce Na(+) transport in the distal nephron. Previous studies suggest that this mechanism may involve the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC), which plays an essential role in NaCl reabsorption in the cells lining the distal convoluted tubule (DCT). Here we show that stimulation of mouse DCT (mDCT) cells with ATP or UTP promoted Ca(2+) transients and decreased the expression of NCC at both mRNA and protein levels. Specific siRNA-mediated silencing of P2Y2 receptors almost completely abolished ATP/UTP-induced Ca(2+) transients and significantly reduced ATP/UTP-induced decrease of NCC expression. To test whether local variations in the intracellular Ca(2+) concentration ([Ca(2+)]i) may control NCC transcription, we overexpressed the Ca(2+)-binding protein parvalbumin selectively in the cytosol or in the nucleus of mDCT cells. The decrease in NCC mRNA upon nucleotide stimulation was abolished in cells overexpressing cytosolic PV but not in cells overexpressing either a nuclear-targeted PV or a mutated PV unable to bind Ca(2+). Using a firefly luciferase reporter gene strategy, we observed that the activity of NCC promoter region from -1 to -2,200 bp was not regulated by changes in [Ca(2+)]i. In contrast, high cytosolic calcium level induced instability of NCC mRNA. We conclude that in mDCT cells: (1) P2Y2 receptor is essential for the intracellular Ca(2+) signaling induced by ATP/UTP stimulation; (2) P2Y2-mediated increase of cytoplasmic Ca(2+) concentration down-regulates the expression of NCC; (3) the decrease of NCC expression occurs, at least in part, via destabilization of its mRNA.

  14. Expression and phosphorylation of the Na+-Cl- cotransporter NCC in vivo is regulated by dietary salt, potassium, and SGK1.

    Science.gov (United States)

    Vallon, Volker; Schroth, Jana; Lang, Florian; Kuhl, Dietmar; Uchida, Shinichi

    2009-09-01

    The Na-Cl cotransporter NCC is expressed in the distal convoluted tubule, activated by phosphorylation, and has been implicated in renal NaCl and K(+) homeostasis. The serum and glucocorticoid inducible kinase 1 (SGK1) contributes to renal NaCl retention and K(+) excretion, at least in part, by stimulating the epithelial Na(+) channel and Na(+)-K(+)-ATPase in the downstream segments of aldosterone-sensitive Na(+)/K(+) exchange. In this study we confirmed in wild-type mice (WT) that dietary NaCl restriction increases renal NCC expression and its phosphorylation at Thr(53), Thr(58), and Ser(71), respectively. This response, however, was attenuated in mice lacking SGK1 (Sgk1(-/-)), which may contribute to impaired NaCl retention in those mice. Total renal NCC expression and phosphorylation at Thr(53), Thr(58), and Ser(71) in WT were greater under low- compared with high-K(+) diet. This finding is consistent with a regulation of NCC to modulate Na(+) delivery to downstream segments of Na(+)/K(+) exchange, thereby modulating K(+) excretion. Dietary K(+)-dependent variation in renal expression of total NCC and phosphorylated NCC were not attenuated in Sgk1(-/-) mice. In fact, high-K(+) diet-induced NCC suppression was enhanced in Sgk1(-/-) mice. The hyperkalemia induced in Sgk1(-/-) mice by a high-K(+) diet may have augmented NCC suppression, thereby increasing Na(+) delivery and facilitating K(+) excretion in downstream segments of impaired Na(+)/K(+) exchange. In summary, changes in NaCl and K(+) intake altered NCC expression and phosphorylation, an observation consistent with a role of NCC in NaCl and K(+) homeostasis. The two maneuvers dissociated plasma aldosterone levels from NCC expression and phosphorylation, implicating additional regulators. Regulation of NCC expression and phosphorylation by dietary NaCl restriction appears to involve SGK1.

  15. Paradoxical activation of the sodium chloride cotransporter (NCC) without hypertension in kidney deficient in a regulatory subunit of Na,K-ATPase, FXYD2.

    Science.gov (United States)

    Arystarkhova, Elena; Ralph, Donna L; Liu, Yi Bessie; Bouley, Richard; McDonough, Alicia A; Sweadner, Kathleen J

    2014-12-01

    Na,K-ATPase generates the driving force for sodium reabsorption in the kidney. Na,K-ATPase functional properties are regulated by small proteins belonging to the FXYD family. In kidney FXYD2 is the most abundant: it is an inhibitory subunit expressed in almost every nephron segment. Its absence should increase sodium pump activity and promote Na(+) retention, however, no obvious renal phenotype was detected in mice with global deletion of FXYD2 (Arystarkhova et al. 2013). Here, increased total cortical Na,K-ATPase activity was documented in the Fxyd2(-/-) mouse, without increased α1β1 subunit expression. We tested the hypothesis that adaptations occur in distal convoluted tubule (DCT), a major site of sodium adjustments. Na,K-ATPase immunoreactivity in DCT was unchanged, and there was no DCT hypoplasia. There was a marked activation of thiazide-sensitive sodium chloride cotransporter (NCC; Slc12a3) in DCT, predicted to increase Na(+) reabsorption in this segment. Specifically, NCC total increased 30% and NCC phosphorylated at T53 and S71, associated with activation, increased 4-6 fold. The phosphorylation of the closely related thick ascending limb (TAL) apical NKCC2 (Slc12a1) increased at least twofold. Abundance of the total and cleaved (activated) forms of ENaC α-subunit was not different between genotypes. Nonetheless, no elevation of blood pressure was evident despite the fact that NCC and NKCC2 are in states permissive for Na(+) retention. Activation of NCC and NKCC2 may reflect an intracellular linkage to elevated Na,K-ATPase activity or a compensatory response to Na(+) loss proximal to the TAL and DCT. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  16. Expression of Na+/glucose co-transporter 1 (SGLT1) is enhanced by supplementation of the diet of weaning piglets with artificial sweeteners.

    Science.gov (United States)

    Moran, Andrew W; Al-Rammahi, Miran A; Arora, Daleep K; Batchelor, Daniel J; Coulter, Erin A; Daly, Kristian; Ionescu, Catherine; Bravo, David; Shirazi-Beechey, Soraya P

    2010-09-01

    In an intensive livestock production, a shorter suckling period allows more piglets to be born. However, this practice leads to a number of disorders including nutrient malabsorption, resulting in diarrhoea, malnutrition and dehydration. A number of strategies have been proposed to overcome weaning problems. Artificial sweeteners, routinely included in piglets' diet, were thought to enhance feed palatability. However, it is shown in rodent models that when included in the diet, they enhance the expression of Na+/glucose co-transporter (SGLT1) and the capacity of the gut to absorb glucose. Here, we show that supplementation of piglets' feed with a combination of artificial sweeteners saccharin and neohesperidin dihydrochalcone enhances the expression of SGLT1 and intestinal glucose transport function. Artificial sweeteners are known to act on the intestinal sweet taste receptor T1R2/T1R3 and its partner G-protein, gustducin, to activate pathways leading to SGLT1 up-regulation. Here, we demonstrate that T1R2, T1R3 and gustducin are expressed together in the enteroendocrine cells of piglet intestine. Furthermore, gut hormones secreted by the endocrine cells in response to dietary carbohydrates, glucagon-like peptides (GLP)-1, GLP-2 and glucose-dependent insulinotrophic peptide (GIP), are co-expressed with type 1 G-protein-coupled receptors (T1R) and gustducin, indicating that L- and K-enteroendocrine cells express these taste elements. In a fewer endocrine cells, T1R are also co-expressed with serotonin. Lactisole, an inhibitor of human T1R3, had no inhibitory effect on sweetener-induced SGLT1 up-regulation in piglet intestine. A better understanding of the mechanism(s) involved in sweetener up-regulation of SGLT1 will allow the identification of nutritional targets with implications for the prevention of weaning-related malabsorption.

  17. String Variant Alias Extraction Method using Ensemble Learner

    Directory of Open Access Journals (Sweden)

    P.Selvaperumal

    2016-02-01

    Full Text Available String variant alias names are surnames which are string variant form of the primary name. Extracting string variant aliases are important in tasks such as information retrieval, information extraction, and name resolution etc. String variant alias extraction involves candidate alias name extraction and string variant alias validation. In this paper, string variant aliases are first extracted from the web and then using seven different string similarity metrics as features, candidate aliases are validated using ensemble classifier random forest. Experiments were conducted using string variant name-alias dataset containing name-alias data for 15 persons containing 30 name-alias pairs. Experimental results show that the proposed method outperforms other similar methods in terms of accuracy.

  18. Cardiovascular mortality and morbidity in patients with type 2 diabetes following initiation of sodium-glucose co-transporter-2 inhibitors versus other glucose-lowering drugs (CVD-REAL Nordic)

    DEFF Research Database (Denmark)

    Birkeland, Kåre I; Jørgensen, Marit E; Carstensen, Bendix

    2017-01-01

    BACKGROUND: In patients with type 2 diabetes and a high cardiovascular risk profile, the sodium-glucose co-transporter-2 (SGLT2) inhibitors empagliflozin and canagliflozin have been shown to lower cardiovascular morbidity and mortality. Using real-world data from clinical practice, we aimed......% (36 362 of 91 320) were women and prevalence of cardiovascular disease was 25% (22 686 of 91 320). 94% of the total SGLT2 inhibitor exposure time was for use of dapagliflozin, with 5% for empagliflozin, and 1% for canagliflozin. Compared with other glucose-lowering drugs, use of SGLT2 inhibitors...

  19. A new variant selection criterion for twin variants in titanium alloys. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Schuman, Christophe [Laboratoire d' Etude des Microstructures et de Mecanique des Materiaux, LEM3, CNRS 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, Metz (France); Bao, Lei; Lecomte, Jean Sebastien; Zhang, Yudong; Raulot, Jean Marc; Philippe, Marie Jeanne; Esling, Claude [LEM3, CNRS 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, Metz (France)

    2012-05-15

    A new selection criterion to explain the activation of the twinning variant is proposed. This criterion is based on the calculation of the deformation energy to create a primary twin. The calculation takes into account the effect of the grain size using a Hall-Petch type relation. This criterion allows to obtain a very good prediction for the twin family selection and twin variant selection. The calculations are compared with the experimental results obtained on T40 (ASTM grade 2) deformed by Channel Die compression. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Mutation Update: The Spectra of Nebulin Variants and Associated Myopathies

    Science.gov (United States)

    Lehtokari, Vilma-Lotta; Kiiski, Kirsi; Sandaradura, Sarah A.; Laporte, Jocelyn; Repo, Pauliina; Frey, Jennifer A.; Donner, Kati; Marttila, Minttu; Saunders, Carol; Barth, Peter G.; den Dunnen, Johan T.; Beggs, Alan H.; Clarke, Nigel F.; North, Kathryn N.; Laing, Nigel G.; Romero, Norma B.; Winder, Thomas L.; Pelin, Katarina; Wallgren-Pettersson, Carina

    2015-01-01

    A mutation update on the nebulin gene (NEB) is necessary because of recent developments in analysis methodology, the identification of increasing numbers and novel types of variants, and a widening in the spectrum of clinical and histological phenotypes associated with this gigantic, 183 exons containing gene. Recessive pathogenic variants in NEB are the major cause of nemaline myopathy (NM), one of the most common congenital myopathies. Moreover, pathogenic NEB variants have been identified in core-rod myopathy and in distal myopathies. In this update, we present the disease-causing variants in NEB in 159 families, 143 families with NM, and 16 families with NM-related myopathies. Eighty-eight families are presented here for the first time. We summarize 86 previously published and 126 unpublished variants identified in NEB. Furthermore, we have analyzed the NEB variants deposited in the Exome Variant Server (http://evs.gs.washington.edu/EVS/), identifying that pathogenic variants are a minor fraction of all coding variants (~7%). This indicates that nebulin tolerates substantial changes in its amino acid sequence, providing an explanation as to why variants in such a large gene result in relatively rare disorders. Lastly, we discuss the difficulties of drawing reliable genotype–phenotype correlations in NEB-associated disease. PMID:25205138

  1. XVCL: XML-based Variant Configuration Language

    DEFF Research Database (Denmark)

    Jarzabek, Stan; Basset, Paul; Zhang, Hongyu;

    2003-01-01

    XVCL (XML-based Variant Configuration Language) is a meta-programming technique and tool that provides effective reuse mechanisms. XVCL is an open source software developed at the National University of Singapore. Being a modern and versatile version of Bassett's frames, a technology that has...... achieved substantial gains in industry, the underlying principles of the XVCL have been thoroughly tested in practice. We envision many other applications in software and non-software domains, as we can apply XVCL to any domain that can be represented as a collection of textual documents....

  2. Clinical variants of idiopathic torsion dystonia.

    Science.gov (United States)

    Fahn, S

    1989-06-01

    Some patients with dystonic movements and postures not known to be caused by environmental or degenerative disorders can be segregated from classical-appearing idiopathic torsion dystonia on the basis of distinctive clinical and pharmacologic features. Many of them should be considered within the family of dystonia, as clinical variants of idiopathic torsion dystonia, while others are better classified as being part of other families of dyskinesias. In the former group are paradoxical dystonia, myoclonic dystonia, diurnal dystonia, and dopa-responsive dystonia. The latter group consists of dystonic tics and the various entities comprising paroxysmal dystonia, namely kinesigenic, nonkinesigenic and hypnogenic dystonia.

  3. Space-variant polarized Airy beam

    CERN Document Server

    Chen, Hao

    2015-01-01

    We experimentally generate an Airy beam with polarization structure while keeping its original amplitude and phase profile intact. This class of Airy beam preserves the acceleration properties. By monitoring their initial polarization structure we have provided insight concerning the self-healing mechanism of Airy beams. We investigate both theoretically and experimentally the self-healing polarization properties of the space-variant polarized Airy beams. Amplitude as well as the polarization structure tends to reform during propagation in spite of the severe truncation of the beam by finite apertures.

  4. Pitfalls and variants in pediatric chest imaging.

    Science.gov (United States)

    García Asensio, D; Fernández Martín, M

    2016-05-01

    Most pitfalls in the interpretation of pediatric chest imaging are closely related with the technique used and the characteristics of pediatric patients. To obtain a quality image that will enable the correct diagnosis, it is very important to use an appropriate technique. It is important to know how technical factors influence the image and to be aware of the possible artifacts that can result from poor patient cooperation. Moreover, radiologists need to be familiar with the normal anatomy in children, with the classic radiologic findings, and with the anatomic and developmental variants to avoid misinterpreting normal findings as pathological.

  5. Variant position of the medial plantar nerve

    Directory of Open Access Journals (Sweden)

    Astik RB

    2011-01-01

    Full Text Available Knowledge of variation of position of the medial plantar nerve is important for the forefoot surgeon for plantar reconstruction, local injection therapy and an excision of interdigital neuroma. During routine dissection of 50-year-old female cadaver, we found the medial plantar nerve and vessels variably located between plantar aponeurosis and the muscles of the first layer of the sole of the right foot. Due to this variant position, the medial plantar nerve and vessels lose their protection from the muscles of the first layer of the sole of the foot and became vulnerable for compression.

  6. Performance comparison of various time variant filters

    Energy Technology Data Exchange (ETDEWEB)

    Kuwata, M. [JEOL Engineering Co. Ltd., Akishima, Tokyo (Japan); Husimi, K.

    1996-07-01

    This paper describes the advantage of the trapezoidal filter used in semiconductor detector system comparing with the other time variant filters. The trapezoidal filter is the compose of a rectangular pre-filter and a gated integrator. We indicate that the best performance is obtained by the differential-integral summing type rectangular pre-filter. This filter is not only superior in performance, but also has the useful feature that the rising edge of the output waveform is linear. We introduce an example of this feature used in a high-energy experiment. (author)

  7. [Necrobiosis lipoidica. Variants on a theme].

    Science.gov (United States)

    Geissler, E; Laaff, H; Technau, K; Bruckner-Tuderman, L; Nashan, D

    2011-08-01

    A 69-year-old patient presented with different skin lesions all of which belonged to group of necrobiosis lipoidica. The initial histologic diagnosis was actinic granuloma O'Brien. A subsequent biopsy was interpreted as granulomatous necrobiosis lipoidica. The history of these necrobiotic variants is reviewed and exemplarily depicted with this case. Necrobiosis lipoidica is part of the spectrum of granulomatous skin disorders. Although its etiology is unclear, an association with diabetes mellitus is often discussed. Multiple therapeutic options exist, but standardized guidelines for treatment are missing.

  8. Oral fibrolipoma: A rare histological variant

    Directory of Open Access Journals (Sweden)

    Treville Pereira

    2014-01-01

    Full Text Available Lipomas are benign soft tissue mesenchymal neoplasms. Fibrolipoma is a histological variant of lipoma that mostly affects the buccal mucosa and causes functional and cosmetic disabilities. The diagnosis and differentiation of fibrolipoma with clinically similar lesions such as fibroma and pleomorphic adenoma is very essential for a correct treatment plan and complete follow-up. This article presents a case of a 35-year-old female with a fibrolipoma on the lingual marginal gingiva of the mandibular left third molar.

  9. Research progress of behavioral variant frontotemporal dementia

    Directory of Open Access Journals (Sweden)

    Xiao-hua GU

    2015-07-01

    Full Text Available There is no epidemiological data of frontotemporal dementia (FTD in China. The application of updated diagnostic criteria, publishing of frontotemporal lobar degeneration (FTLD consensus in China, development of multimodal imaging and biomarkers promote the clinical understanding on behavioral variant frontotemporal dementia (bvFTD. There is still no drugs treating FTD approved by U.S. Food and Drug Administration (FDA. Multidisciplinary intervention may delay the progression of bvFTD. DOI: 10.3969/j.issn.1672-6731.2015.07.006

  10. Immunogenic variants obtained by mutagenesis of mouse mastocytoma P815. V. H-2 associativity of variant-specific antigens.

    Science.gov (United States)

    Van Snick, J; Maryanski, J; Van Pel, A; Parmiani, G; Boon, T

    1982-11-01

    By in vitro mutagenesis of mastocytoma P815, it is possible to obtain tumor cell variants that are rejected by syngeneic mice (tum-). Most of these variants carry new individual antigens and stimulate a specific cytolytic T cell (CTL) response in mixed leukocyte tumor cell culture (MLTC). The H-2 associativity of this response was examined for six different variants by measuring the inhibition of cell-mediated cytolysis by antibodies directed against products of the K or the D end of the H-2d complex. The lysis was either not inhibited (variants P91 and P116) or inhibited selectively by anti-Kd (variants P21, P32 and P198) or anti-Dd antibodies (variant P35). All these tum- variants expressed Kd and Dd antigens as measured by absorption of H-2 alloantisera. Long-term CTL clones can be obtained that are specific for individual tum- antigens. The pattern of H-2 associativity obtained with MLTC-derived CTL against four tum- variants was verified with CTL clones directed against the specific antigens of these variants. Concordant results were observed in all cases. In addition to CTL clones specific for tum- antigens, it is possible to isolate clones against a P815 tumor-associated antigen found on all P815 tum- variants. For these clones no clear associativity with either Kd or Dd products was found.

  11. Schizophrenia copy number variants and associative learning

    Science.gov (United States)

    Clifton, N E; Pocklington, A J; Scholz, B; Rees, E; Walters, J T R; Kirov, G; O'Donovan, M C; Owen, M J; Wilkinson, L S; Thomas, K L; Hall, J

    2017-01-01

    Large-scale genomic studies have made major progress in identifying genetic risk variants for schizophrenia. A key finding from these studies is that there is an increased burden of genomic copy number variants (CNVs) in schizophrenia cases compared with controls. The mechanism through which these CNVs confer risk for the symptoms of schizophrenia, however, remains unclear. One possibility is that schizophrenia risk CNVs impact basic associative learning processes, abnormalities of which have long been associated with the disorder. To investigate whether genes in schizophrenia CNVs impact on specific phases of associative learning we combined human genetics with experimental gene expression studies in animals. In a sample of 11 917 schizophrenia cases and 16 416 controls, we investigated whether CNVs from patients with schizophrenia are enriched for genes expressed during the consolidation, retrieval or extinction of associative memories. We show that CNVs from cases are enriched for genes expressed during fear extinction in the hippocampus, but not genes expressed following consolidation or retrieval. These results suggest that CNVs act to impair inhibitory learning in schizophrenia, potentially contributing to the development of core symptoms of the disorder. PMID:27956746

  12. [Variant phenotype of Lesch-Nyhan syndrome].

    Science.gov (United States)

    Torres Jiménez, Rosa; García García, Marta; García Puig, Juan

    2011-01-29

    Lesch-Nyhan syndrome (LNS) and LNS variants are due to mutations in the HPRT1 gene causing HPRT enzymatic activity deficiency. We report a patient presenting a variant phenotype and a major genetic defect. The mutation has been previously reported as always associated with complete Lesch-Nyhan phenotype. We analyzed the presence of complete HPRT mRNA in this patient, in two patients with the complete Lesch Nyhan syndrome phenotype, and in control subjects. We found a minor amount of normal HPRT mRNA in the present patient but also in the two patients with splice mutation and the complete Lesch Nyhan syndrome phenotype. To our knowledge, this patient is the first report of a major genetic defect, with no detectable enzymatic activity, and a partial HPRT deficiency phenotype. Our results question the hypothesis of a normally spliced HPRT cDNA as the sole cause of the patient partial phenotype. Copyright © 2010 Elsevier España, S.L. All rights reserved.

  13. Clinical relevance of hepatitis B virus variants

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The hepatitis B virus (HBV) is a global public health problem with more than 240 million people chronicallyinfected worldwide, who are at risk for end-stage liverdisease and hepatocellular carcinoma. There are anestimated 600000 deaths annually from complications ofHBV-related liver disease. Antiviral therapy with nucleos/tide analogs (NA) targeting the HBV polymerase (P) caninhibit disease progression by long-term suppression ofHBV replication. However, treatment may fail with firstgeneration NA therapy due to the emergence of drugresistantmutants, as well as incomplete medicationadherence. The HBV replicates via an error-prone reversetranscriptase leading to quasispecies. Due to overlappingopen reading frames mutations within the HBV P cancause concomitant changes in the HBV surface gene (S )and vice versa. HBV quasispecies diversity is associatedwith response to antiviral therapy, disease severity andlong-term clinical outcomes. Specific mutants havebeen associated with antiviral drug resistance, immuneescape, liver fibrosis development and tumorgenesis.An understanding of HBV variants and their clinicalrelevance may be important for monitoring chronichepatitis B disease progression and treatment response.In this review, we will discuss HBV molecular virology,mechanism of variant development, and their potentialclinical impact.

  14. Canonical and variant histones of protozoan parasites.

    Science.gov (United States)

    Dalmasso, Maria Carolina; Sullivan, William Joseph; Angel, Sergio Oscar

    2011-06-01

    Protozoan parasites have tremendously diverse lifestyles that require adaptation to a remarkable assortment of different environmental conditions. In order to complete their life cycles, protozoan parasites rely on fine-tuning gene expression. In general, protozoa use novel regulatory elements, transcription factors, and epigenetic mechanisms to regulate their transcriptomes. One of the most surprising findings includes the nature of their histones--these primitive eukaryotes lack some histones yet harbor novel histone variants of unknown function. In this review, we describe the histone components of different protozoan parasites based on literature and database searching. We summarize the key discoveries regarding histones and histone variants and their impact on chromatin regulation in protozoan parasites. In addition, we list histone genes IDs, sequences, and genomic localization of several protozoan parasites and Microsporidia histones, obtained from a thorough search of genome databases. We then compare these findings with those observed in higher eukaryotes, allowing us to highlight some novel aspects of epigenetic regulation in protists and to propose questions to be addressed in the upcoming years.

  15. Flavonoids as Inhibitors of Human Butyrylcholinesterase Variants

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    Maja Katalinić

    2014-01-01

    Full Text Available The inhibition of butyrylcholinesterase (BChE, EC 3.1.1.8 appears to be of interest in treating diseases with symptoms of reduced neurotransmitter levels, such as Alzheimer’s disease. However, BCHE gene polymorphism should not be neglected in research since it could have an effect on the expected outcome. Several well-known cholinergic drugs (e.g. galantamine, huperzine and rivastigmine originating from plants, or synthesised as derivatives of plant compounds, have shown that herbs could serve as a source of novel target-directed compounds. We focused our research on flavonoids, biologically active polyphenolic compounds found in many plants and plant-derived products, as BChE inhibitors. All of the tested flavonoids: galangin, quercetin, fisetin and luteolin reversibly inhibited usual, atypical, and fluoride-resistant variants of human BChE. The inhibition potency increased in the following order, identically for all three BChE variants: luteolin

  16. Kenny-Caffey syndrome: an Arab variant?

    Science.gov (United States)

    Sabry, M A; Farag, T I; Shaltout, A A; Zaki, M; Al-Mazidi, Z; Abulhassan, S J; Al-Torki, N; Quishawi, A; Al Awadi, S A

    1999-01-01

    We describe 2 unrelated Bedouin girls who met the criteria for the diagnosis of Kenny-Caffey syndrome. The girls had some unusual features--microcephaly and psychomotor retardation--that distinguish the Kenny-Caffey syndrome profile in Arab children from the classical Kenny-Caffey syndrome phenotype characterized by macrocephaly and normal intelligence. The 2 girls did not harbor the 22q11 microdeletion (the hallmark of the DiGeorge cluster of diseases) that we previously reported in another Bedouin family with the Kenny-Caffey syndrome (Sabry et al. J Med Genet 1998: 35(1): 31-36). This indicates considerable genetic heterogeneity for this syndrome. We also review previously reported 44 Arab/Bedouin patients with the same profile of hypoparathyroidism, short stature, seizures, mental retardation and microcephaly. Our results suggest that these patients represent an Arab variant of Kenny-Caffey syndrome with characteristic microcephaly and psychomotor retardation. We suggest that all patients with Kenny-Caffey syndrome should be investigated for the 22q11 microdeletion. Other possible genetic causes for the Kenny-Caffey syndrome or its Arab variant include chromosome 10p abnormalities.

  17. Synthesis of novel l-rhamnose derived acyclic C-nucleosides with substituted 1,2,3-triazole core as potent sodium-glucose co-transporter (SGLT) inhibitors.

    Science.gov (United States)

    Putapatri, Siddamal Reddy; Kanwal, Abhinav; Banerjee, Sanjay K; Kantevari, Srinivas

    2014-03-15

    Sodium-glucose co-transporter (SGLT) inhibitors are a novel class of therapeutic agents for the treatment of type 2 diabetes by preventing renal glucose reabsorption. In our efforts to identify novel inhibitors of SGLT, we synthesized a series of l-rhamnose derived acyclic C-nucleosides with 1,2,3-triazole core. The key β-ketoester building block 4 prepared from l-rhamnose in five steps, was reacted with various aryl azides to produce the respective 1,2,3-triazole derivatives in excellent yields. Deprotection of acetonide group gave the desired acyclic C-nucleosides 7a-o. All the new compounds were screened for their sodium-glucose co-transporters (SGLT1 and SGLT2) inhibition activity using recently developed cell-based nonradioactive fluorescence glucose uptake assay. Among them, 7m with IC50: 125.9nM emerged as the most potent SGLT2 inhibitor. On the other hand compound 7d exhibited best selectivity for inhibition of SGLT2 (IC50: 149.1nM) over SGLT1 (IC50: 693.2nM). The results presented here demonstrated the utility of acyclic C-nucleosides as novel SGLT inhibitors for future investigations.

  18. Progress in Synthesis of C-Aryl Glucosides Sodium Glucose Co-Transporter 2 Inhibitors%C-芳基糖苷类SGLT2抑制剂的合成研究进展

    Institute of Scientific and Technical Information of China (English)

    杜铁奇; 郑亿; 朱灵龙; 钟为慧

    2015-01-01

    Sodium glucose Co-transporter 2 (SGLT2) has been a hot spot of research on the treatment for type II diabetes. Inhibiting SGLT2, which works in the kidney specially, can reduce renal glucose reab-sorption, excrete excess glucose through the urine and lower the plasma glucose. This paper briefly reviews the synthetic routes to the C-aryl glucosides sodium glucose Co-transporter 2 inhibitors on the market, such as Ipragliflozin, Empagliflozin.%钠-葡萄糖协同转运蛋白2(SGLT2)抑制剂是目前Ⅱ型糖尿病药物研究的热点之一。通过抑制这种在肾脏特异性表达的钠-葡萄糖协同转运蛋白2(SGLT2),可以减少肾脏对葡萄糖的重吸收,增加葡萄糖在尿中的排泄,从而降低血糖。本文将针对已上市的C-芳基糖苷类SGLT2抑制剂伊格列净和恩格列净的合成路线进行简要评述。

  19. IRBIT Interacts with the Catalytic Core of Phosphatidylinositol Phosphate Kinase Type Iα and IIα through Conserved Catalytic Aspartate Residues.

    Directory of Open Access Journals (Sweden)

    Hideaki Ando

    Full Text Available Phosphatidylinositol phosphate kinases (PIPKs are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5P2, a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein released with inositol 1,4,5-trisphosphate is a multifunctional protein that regulates diverse target proteins. Here, we report that IRBIT forms signaling complexes with members of the PIPK family. IRBIT bound to all PIPK isoforms in heterologous expression systems and specifically interacted with PIPK type Iα (PIPKIα and type IIα (PIPKIIα in mouse cerebellum. Site-directed mutagenesis revealed that two conserved catalytic aspartate residues of PIPKIα and PIPKIIα are involved in the interaction with IRBIT. Furthermore, phosphatidylinositol 4-phosphate, Mg2+, and/or ATP interfered with the interaction, suggesting that IRBIT interacts with catalytic cores of PIPKs. Mutations of phosphorylation sites in the serine-rich region of IRBIT affected the selectivity of its interaction with PIPKIα and PIPKIIα. The structural flexibility of the serine-rich region, located in the intrinsically disordered protein region, is assumed to underlie the mechanism of this interaction. Furthermore, in vitro binding experiments and immunocytochemistry suggest that IRBIT and PIPKIα interact with the Na+/HCO3- cotransporter NBCe1-B. These results suggest that IRBIT forms signaling complexes with PIPKIα and NBCe1-B, whose activity is regulated by PI(4,5P2.

  20. Maternal inheritance and mitochondrial DNA variants in familial Parkinson's disease

    OpenAIRE

    Pfeiffer Ronald F; Rudolph Alice; Halter Cheryl A; Pauciulo Michael W; Kissell Diane K; Pankratz Nathan; Simon David K; Nichols William C; Foroud Tatiana

    2010-01-01

    Abstract Background Mitochondrial function is impaired in Parkinson's disease (PD) and may contribute to the pathogenesis of PD, but the causes of mitochondrial impairment in PD are unknown. Mitochondrial dysfunction is recapitulated in cell lines expressing mitochondrial DNA (mtDNA) from PD patients, implicating mtDNA variants or mutations, though the role of mtDNA variants or mutations in PD risk remains unclear. We investigated the potential contribution of mtDNA variants or mutations to t...

  1. Genital mycotic infections with canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus: a pooled analysis of clinical studies.

    Science.gov (United States)

    Nyirjesy, Paul; Sobel, Jack D; Fung, Albert; Mayer, Cristiana; Capuano, George; Ways, Kirk; Usiskin, Keith

    2014-06-01

    To characterize genital mycotic infections with canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes mellitus (T2DM) using pooled data from Phase 3 studies. Genital mycotic infections with canagliflozin 100 and 300 mg were evaluated in Population 1 (N = 2313; mean exposure [weeks]: canagliflozin, 24.3; placebo, 23.8), including patients from four placebo-controlled studies, and Population 2 (N = 9439; mean exposure [weeks]: canagliflozin, 68.1; control, 64.4), including patients from eight placebo/active-controlled studies (including older patients and those with renal impairment or high cardiovascular disease risk). ClinicalTrials.gov, NCT01081834; NCT01106625; NCT01106677; NCT01106690; NCT01032629; NCT01064414; NCT01106651; NCT00968812. Adverse events suggestive of genital mycotic infections were recorded, with additional information collected using supplemental electronic case report forms. In Population 1, genital mycotic infection incidence was higher with canagliflozin 100 and 300 mg than placebo (95% confidence intervals excluded zero) in females (10.4%, 11.4%, 3.2%) and males (4.2%, 3.7%, 0.6%). These were generally mild to moderate in intensity, none were serious, and few led to discontinuation. Most events with canagliflozin were treated with antifungal therapies, and median symptom duration following treatment initiation was similar across groups; few patients had >1 event (females, 2.3%; males, 0.9%). Findings with canagliflozin 100 and 300 mg versus control were similar in Population 2 (females: 14.7%, 13.9%, 3.1%; males: 7.3%, 9.3%, 1.6%); a low proportion of males underwent circumcision across groups. Most events with canagliflozin occurred within the first 4 months in females and first year in males; no consistent evidence of dose dependence was observed. Key limitations included lack of laboratory confirmation for most events and variable treatment methods. Genital mycotic infection incidences

  2. Sodium–glucose cotransporter-2 inhibition and acidosis in patients with type 2 diabetes: a review of US FDA data and possible conclusions

    Directory of Open Access Journals (Sweden)

    D'Elia JA

    2017-06-01

    Full Text Available John A D’Elia,1 Alissa R Segal,1,2 George P Bayliss,3 Larry A Weinrauch1 1Kidney and Hypertension Section, Joslin Diabetes Center, Harvard Medical School, 2Department of Pharmacy Practice, MCPHS University, Boston, MA, 3Division of Kidney Diseases and Hypertension, Rhode Island Hospital, Alpert Medical School, Brown University, Providence, RI, USA Objective: To evaluate whether adverse event reports to the US Food and Drug Administration on incidents of ketoacidosis from use of sodium glucose cotransport inhibitors (SGLT2 inhibitors provide insight into ways this new class of drugs is being prescribed with other antihyperglycemic agents; to examine possible mechanisms to explain ketoacidosis.Design and methods: Reports of adverse events concerned to SGLT2 inhibitors, namely, empagliflozin, dapagliflozin, and canagliflozin were obtained under the Freedom of Information Act for 5 years ending in August 31, 2015. The data were evaluated for incidents of ketoacidosis by looking for keywords such as diabetic ketoacidosis, ketoacidosis, lactic acidosis, acidosis, and metabolic acidosis. Results were tabulated individually for empagliflozin (n=260 adverse event reports, dapagliflozin (n=520, and canagliflozin (n=2159. Adverse events were categorized according to age, gender, and insulin use.Results: There were 46, 144, and 450 reports of ketoacidosis concerned with the use of empagliflozin, dapagliflozin, and canagliflozin, respectively. The use of SGLT2 inhibitors was not strictly limited to patients with type 2 diabetes but was cut across categories of insulin use, including a total of 172 cases of SGLT2-related ketoacidosis in individuals above the age of 40 who were not on insulin.Conclusion: Further studies should focus to detect pleiotropic effects of SGLT2 inhibitors, particularly with other oral antihyperglycemic drugs or insulin. A review of the literature suggests that patients with type 2 diabetes with low C-peptide level may be at

  3. Pharmacodynamic effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor, from a randomized study in patients with type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Sue Sha

    Full Text Available This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes.Patients (N = 116 discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in the United States and Germany, or canagliflozin 30 mg once daily or placebo at 1 study center in Korea, while maintaining an isocaloric diet for 2 weeks. On Days -1, 1, and 16, urinary glucose excretion (UGE, plasma glucose (PG, fasting PG (FPG, and insulin were measured. The renal threshold for glucose (RTG was calculated from UGE, PG, and estimated glomerular filtration rate. Safety was evaluated based on adverse event (AE reports, vital signs, electrocardiograms, clinical laboratory tests, and physical examinations.Canagliflozin increased UGE dose-dependently (,80-120 g/day with canagliflozin $100 mg, with increases maintained over the 14-day dosing period with each dose. Canagliflozin dose-dependently decreased RTG, with maximal reductions to ,4-5 mM (72-90 mg/dL. Canagliflozin also reduced FPG and 24-hour mean PG; glucose reductions were seen on Day 1 and maintained over 2 weeks. Plasma insulin reductions with canagliflozin were consistent with observed PG reductions. Canagliflozin also reduced body weight. AEs were transient, mild to moderate in intensity, and balanced across groups; 1 canagliflozin-treated female reported an episode of vaginal candidiasis. Canagliflozin did not cause hypoglycemia, consistent with the RTG values remaining above the hypoglycemia threshold. At Day 16, there were no clinically meaningful changes in urine volume, urine electrolyte excretion, renal function, or routine laboratory test values.Canagliflozin increased UGE and decreased RTG, leading to

  4. Efficacy and Safety of Canagliflozin, a Sodium-Glucose Cotransporter 2 Inhibitor, as Add-on to Insulin in Patients With Type 1 Diabetes.

    Science.gov (United States)

    Henry, Robert R; Thakkar, Payal; Tong, Cindy; Polidori, David; Alba, Maria

    2015-12-01

    This study assessed the efficacy and safety of canagliflozin, a sodium-glucose cotransporter 2 inhibitor, as add-on to insulin in adults with type 1 diabetes. This 18-week, double-blind, phase 2 study randomized 351 patients (HbA1c 7.0-9.0% [53-75 mmol/mol]) on multiple daily insulin injections or continuous subcutaneous insulin infusion to canagliflozin 100 or 300 mg or placebo. The primary end point was the proportion of patients achieving at week 18 both HbA1c reduction from baseline of ≥0.4% (≥4.4 mmol/mol) and no increase in body weight. Other end points included changes in HbA1c, body weight, and insulin dose, as well as hypoglycemia incidence. Safety was assessed by adverse event (AE) reports. More patients had both HbA1c reduction ≥0.4% and no increase in body weight with canagliflozin 100 and 300 mg versus placebo at week 18 (36.9%, 41.4%, 14.5%, respectively; P canagliflozin doses provided reductions in HbA1c, body weight, and insulin dose versus placebo over 18 weeks. The incidence of hypoglycemia was similar across groups; severe hypoglycemia rates were low (1.7-6.8%). Overall incidence of AEs was 55.6%, 67.5%, and 54.7% with canagliflozin 100 and 300 mg and placebo; discontinuation rates were low (0.9-1.3%). Increased incidence of ketone-related AEs (5.1%, 9.4%, 0%), including the specific AE of diabetic ketoacidosis (DKA) (4.3%, 6.0%, 0%), was seen with canagliflozin 100 and 300 mg versus placebo. Canagliflozin provided reductions in HbA1c, body weight, and insulin dose with no increase in hypoglycemia, but increased rates of ketone-related AEs, including DKA, in adults with type 1 diabetes inadequately controlled with insulin. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  5. Pharmacodynamic effects of canagliflozin, a sodium glucose co-transporter 2 inhibitor, from a randomized study in patients with type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Sue Sha

    Full Text Available INTRODUCTION: This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes. METHODS: Patients (N = 116 discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in the United States and Germany, or canagliflozin 30 mg once daily or placebo at 1 study center in Korea, while maintaining an isocaloric diet for 2 weeks. On Days -1, 1, and 16, urinary glucose excretion (UGE, plasma glucose (PG, fasting PG (FPG, and insulin were measured. The renal threshold for glucose (RTG was calculated from UGE, PG, and estimated glomerular filtration rate. Safety was evaluated based on adverse event (AE reports, vital signs, electrocardiograms, clinical laboratory tests, and physical examinations. RESULTS: Canagliflozin increased UGE dose-dependently (∼80-120 g/day with canagliflozin ≥100 mg, with increases maintained over the 14-day dosing period with each dose. Canagliflozin dose-dependently decreased RTG, with maximal reductions to ∼4-5 mM (72-90 mg/dL. Canagliflozin also reduced FPG and 24-hour mean PG; glucose reductions were seen on Day 1 and maintained over 2 weeks. Plasma insulin reductions with canagliflozin were consistent with observed PG reductions. Canagliflozin also reduced body weight. AEs were transient, mild to moderate in intensity, and balanced across groups; 1 canagliflozin-treated female reported an episode of vaginal candidiasis. Canagliflozin did not cause hypoglycemia, consistent with the RTG values remaining above the hypoglycemia threshold. At Day 16, there were no clinically meaningful changes in urine volume, urine electrolyte excretion, renal function, or routine laboratory test values. CONCLUSIONS

  6. Pharmacodynamic Effects of Canagliflozin, a Sodium Glucose Co-Transporter 2 Inhibitor, from a Randomized Study in Patients with Type 2 Diabetes

    Science.gov (United States)

    Sha, Sue; Devineni, Damayanthi; Ghosh, Atalanta; Polidori, David; Hompesch, Marcus; Arnolds, Sabine; Morrow, Linda; Spitzer, Heike; Demarest, Keith; Rothenberg, Paul

    2014-01-01

    Introduction This randomized, double-blind, placebo-controlled, single and multiple ascending-dose study evaluated the pharmacodynamic effects and safety/tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in patients with type 2 diabetes. Methods Patients (N = 116) discontinued their antihyperglycemic medications 2 weeks before randomization. Patients received canagliflozin 30, 100, 200, or 400 mg once daily or 300 mg twice daily, or placebo at 2 study centers in the United States and Germany, or canagliflozin 30 mg once daily or placebo at 1 study center in Korea, while maintaining an isocaloric diet for 2 weeks. On Days –1, 1, and 16, urinary glucose excretion (UGE), plasma glucose (PG), fasting PG (FPG), and insulin were measured. The renal threshold for glucose (RTG) was calculated from UGE, PG, and estimated glomerular filtration rate. Safety was evaluated based on adverse event (AE) reports, vital signs, electrocardiograms, clinical laboratory tests, and physical examinations. Results Canagliflozin increased UGE dose-dependently (∼80–120 g/day with canagliflozin ≥100 mg), with increases maintained over the 14-day dosing period with each dose. Canagliflozin dose-dependently decreased RTG, with maximal reductions to ∼4–5 mM (72–90 mg/dL). Canagliflozin also reduced FPG and 24-hour mean PG; glucose reductions were seen on Day 1 and maintained over 2 weeks. Plasma insulin reductions with canagliflozin were consistent with observed PG reductions. Canagliflozin also reduced body weight. AEs were transient, mild to moderate in intensity, and balanced across groups; 1 canagliflozin-treated female reported an episode of vaginal candidiasis. Canagliflozin did not cause hypoglycemia, consistent with the RTG values remaining above the hypoglycemia threshold. At Day 16, there were no clinically meaningful changes in urine volume, urine electrolyte excretion, renal function, or routine laboratory test values. Conclusions

  7. Na+/glucose co-transporter abundance and activity in the small intestine of lambs: enhancement by abomasal infusion of casein.

    Science.gov (United States)

    Mabjeesh, Sameer J; Guy, Dafna; Sklan, David

    2003-05-01

    The purpose of the present study was to determine the effect of abomasal casein infusion on glucose uptake and abundance of the Na+/glucose co-transporter (SGLT1) 1 in the ovine small intestine. Lambs (body weight 35 (sem 1.0) kg) were surgically fitted with abomasal infusion catheters and were fed diets containing equal portions of wheat hay and cracked maize. Lambs were infused with either 500 g water/d or with 500 g water containing 35 g casein/d. The infusion period lasted 10 d, after which lambs were killed, exsanguinated and eviscerated. Brush border membrane vesicles (BBMV) were prepared using mucosa from different small intestinal regions. Intake and total tract digestibility of nutrients were similar between treatments and averaged 1134, 1142 and 486 g/d and 67, 70, and 94 % for DM, organic matter and non-structural carbohydrates respectively. Crude protein (Nx6.25) digestibility was 15 % greater in the casein-infused than control lambs. Glucose uptake to BBMV ranged from 101 to 337 pmol/mg protein per s along the small intestine and was greatest in the mid-section of the small intestine. In the mid-jejunum, glucose uptake was greater (Pinfused with casein and averaged 120 pmol/mg protein per s compared with 68 pmol/mg protein per s in the control group. SGLT1 affinity was similar between treatments and averaged 104 microm in the different segments of the small intestine of lambs. However, lambs infused with casein exhibited similar values along the small intestine and affinity averaged 106 microm, while in the control group a greater affinity (85 microm) was measured in the mid-jejunum. SGLT1 protein abundance was correlated with glucose uptake in the BBMV in the casein-treated lambs, but not in the control group. These results suggest that glucose uptake along the small intestine of lambs is influenced by casein or its derivatives in the small intestine via SGLT1 affinity and activity at the brush border membrane, and that SGLT1 activity may be regulated

  8. Clinical profile of patients with type 2 diabetes mellitus treated with sodium- glucose cotransporter-2 inhibitors and experience in real-world clinical practice in Spain.

    Science.gov (United States)

    Cuatrecasas, Gabriel; Goñi-Goicoechea, Fernando

    2016-11-01

    The main aim of the treatment of type 2 diabetes is overall control of cardiovascular risk factors. Almost 50% of patients with type 2 diabetes do not achieve glycaemic targets, and a much higher percentage do not achieve weight and blood pressure targets, despite the therapeutic arsenal that has appeared in the last decade for the treatment of this disease. In addition, antidiabetic secretatogues and insulin are associated with weight gain and an increased risk of hyperglycaemic episodes. Clinical practice guidelines recommend sodium-glucose cotransporter-2 inhibitors (SGLT2i) as an alternative in the same therapeutic step as the other options after initiation of metformin therapy. The present study reviews the most appropriate patient profile for SGLT2i therapy, based on their safety and efficacy demonstrated in controlled clinical trials. The article discusses which patients are at risk of experiencing the possible secondary effects due to the mechanism of action of this new therapeutic class, in whom SGLT2i should be used with caution. These considerations on the profile of patients suitable for SGLT2i therapy are contrasted with the results obtained in daily clinical practice, both in retrospective studies from other countries and from real-world experiences in Spain. This article presents a selection of studies performed in distinct centres with a minimum follow-up of 6 months and compares their results with those from clinical trials. SGLT2i are used in clinical practice in any therapeutic step and the efficacy results are very similar to those reported by controlled clinical trials, with a slightly higher proportion of genitourinary infections and a low dropout rate. Half the reported patients are diabetics receiving insulin therapy plus a gliflozin, showing the wide uptake of this therapeutic strategy by clinicians. SGLT2i are especially attractive due to their additional effectiveness in weight and blood pressure control and the possibility of using them

  9. An overview of the effect of sodium glucose cotransporter 2 inhibitor monotherapy on glycemic and other clinical laboratory parameters in type 2 diabetes patients

    Directory of Open Access Journals (Sweden)

    Wang Y

    2016-07-01

    Full Text Available Yaowen Wang,1 Xueting Hu,2 Xueying Liu,3 Zengqi Wang2 1Department of Clinical Laboratory, Weifang People’s Hospital, 2Department of Clinical Laboratory, Weifang Traditional Chinese Hospital, Weifang, 3Department of Clinical Laboratory, The Third Hospital of Jinan, Jinan, People’s Republic of China Objectives: We aimed to determine the effect of sodium glucose cotransporter 2 (SGLT2 inhibitor monotherapy on glycemic and other clinical laboratory parameters versus other antidiabetic medications or placebo therapy in patients with type 2 diabetes mellitus. In addition, we aimed to investigate the risk of diabetic ketoacidosis associated with SGLT2 inhibitor therapy and evaluate its weight-sparing ability. Design: Meta-analysis. Materials and methods: PubMed and MEDLINE were searched to identify eligible studies up to December 2015. Randomized controlled trials that assessed the efficacy and safety of SGLT2 inhibitor monotherapy versus placebo therapy or active control were considered. The Cochrane Collaboration Risk of Bias Tool was used to evaluate quality and bias. The mean ­difference was used to evaluate the glycemic and other clinical laboratory parameters for SGLT2 inhibitor intervention versus control by drugs or placebo. Similarly, the risk ratio was used to assess adverse events, and the I2 was used to evaluate heterogeneity. Results: SGLT2 inhibitors significantly decreased glycated hemoglobin (HbA1c (P<0.001, weight (P<0.001, and the low-density lipoprotein/high-density lipoprotein ratio (P=0.03 compared with placebo therapy. No statistically significant changes were found in fasting plasma glucose, 2-hour postprandial glucose, or lipid parameters. Significant changes in the uric acid level were found for SGLT2 inhibitors versus placebo therapy (P=0.005 or active control (P<0.001. Although no significant change in levels of ketones occurred (P=0.93, patients receiving SGLT2 inhibitors were at greater risk of increased ketone bodies

  10. Invokana (Canagliflozin) as a dual inhibitor of acetylcholinesterase and sodium glucose co-transporter 2: advancement in Alzheimer's disease- diabetes type 2 linkage via an enzoinformatics study.

    Science.gov (United States)

    Rizvi, Syed M D; Shakil, Shahnawaz; Biswas, Deboshree; Shakil, Shazi; Shaikh, Sibhghatulla; Bagga, Paramdeep; Kamal, Mohammad A

    2014-04-01

    Acetylcholinesterase (AChE) is a primary target for Alzheimer's therapy while recently sodium glucose cotransporter 2 (SGLT2) has gained importance as a potential target for Type 2 Diabetes Mellitus (T2DM) therapy. The present study emphasizes the molecular interactions between a new Food and Drug Administration (FDA) approved antidiabetic drug 'Invokana' (chemically known as Canagliflozin) with AChE and SGLT2 to establish a link between the treatment of T2DM and Alzheimer's Disease (AD). Docking study was performed using 'Autodock4.2'. Both hydrophobic and π-π interactions play an important role in the correct positioning of Canagliflozin within SGLT2 and catalytic site (CAS) of AChE to permit docking. Free energy of binding (ΔG) for 'Canagliflozin-SGLT2' interaction and 'Canagliflozin - CAS domain of AChE' interaction were found to be -10.03 kcal/mol and -9.40 kcal/mol, respectively. During 'Canagliflozin-SGLT2' interaction, Canagliflozin was found to interact with the most important amino acid residue Q457 of SGLT2. This residue is known for its interaction with glucose during reabsorption in kidney. However, 'Canagliflozin-CAS domain of AChE' interaction revealed that out of the three amino acids constituting the catalytic triad (S203, H447 and E334), two amino acid residues (S203 and H447) interact with Canagliflozin. Hence, Invokana (Canagliflozin) might act as a potent dual inhibitor of AChE and SGLT2. However, scope still remains in the determination of the three-dimensional structure of SGLT2-Canagliflozin and AChE-Canagliflozin complexes by X-ray crystallography to validate the described data. Since the development of diabetes is associated with AD, the design of new AChE inhibitors based on antidiabetic drug scaffolds would be particularly beneficial. Moreover, the present computational study reveals that Invokana (Canagliflozin) is expected to form the basis of a future dual therapy against diabetes associated neurological disorders.

  11. Rare variant detection using family-based sequencing analysis.

    Science.gov (United States)

    Peng, Gang; Fan, Yu; Palculict, Timothy B; Shen, Peidong; Ruteshouser, E Cristy; Chi, Aung-Kyaw; Davis, Ronald W; Huff, Vicki; Scharfe, Curt; Wang, Wenyi

    2013-03-05

    Next-generation sequencing is revolutionizing genomic analysis, but this analysis can be compromised by high rates of missing true variants. To develop a robust statistical method capable of identifying variants that would otherwise not be called, we conducted sequence data simulations and both whole-genome and targeted sequencing data analysis of 28 families. Our method (Family-Based Sequencing Program, FamSeq) integrates Mendelian transmission information and raw sequencing reads. Sequence analysis using FamSeq reduced the number of false negative variants by 14-33% as assessed by HapMap sample genotype confirmation. In a large family affected with Wilms tumor, 84% of variants uniquely identified by FamSeq were confirmed by Sanger sequencing. In children with early-onset neurodevelopmental disorders from 26 families, de novo variant calls in disease candidate genes were corrected by FamSeq as mendelian variants, and the number of uniquely identified variants in affected individuals increased proportionally as additional family members were included in the analysis. To gain insight into maximizing variant detection, we studied factors impacting actual improvements of family-based calling, including pedigree structure, allele frequency (common vs. rare variants), prior settings of minor allele frequency, sequence signal-to-noise ratio, and coverage depth (∼20× to >200×). These data will help guide the design, analysis, and interpretation of family-based sequencing studies to improve the ability to identify new disease-associated genes.

  12. Behavioral variant frontotemporal dementia with dominant gait disturbances - case report.

    Directory of Open Access Journals (Sweden)

    Wojciech Guenter

    2016-04-01

    Presented case emphasises the significance of accurately gathered anamnesis with patient and his family. Behavioural variant frontotemporal dementia should be considered in cases of unexplained gait abnormalities.

  13. A unified phylogeny-based nomenclature for histone variants

    Directory of Open Access Journals (Sweden)

    Talbert Paul B

    2012-06-01

    Full Text Available Abstract Histone variants are non-allelic protein isoforms that play key roles in diversifying chromatin structure. The known number of such variants has greatly increased in recent years, but the lack of naming conventions for them has led to a variety of naming styles, multiple synonyms and misleading homographs that obscure variant relationships and complicate database searches. We propose here a unified nomenclature for variants of all five classes of histones that uses consistent but flexible naming conventions to produce names that are informative and readily searchable. The nomenclature builds on historical usage and incorporates phylogenetic relationships, which are strong predictors of structure and function. A key feature is the consistent use of punctuation to represent phylogenetic divergence, making explicit the relationships among variant subtypes that have previously been implicit or unclear. We recommend that by default new histone variants be named with organism-specific paralog-number suffixes that lack phylogenetic implication, while letter suffixes be reserved for structurally distinct clades of variants. For clarity and searchability, we encourage the use of descriptors that are separate from the phylogeny-based variant name to indicate developmental and other properties of variants that may be independent of structure.

  14. Phenotypic and Enzymatic Comparative Analysis of the KPC Variants, KPC-2 and Its Recently Discovered Variant KPC-15

    OpenAIRE

    Dongguo Wang; Jiayu Chen; Linjun Yang; Yonghua Mou; Yijun Yang

    2014-01-01

    Sixteen different variants (KPC-2 to KPC-17) in the KPC family have been reported, and most current studies are focusing on KPC-2 and KPC-3. The KPC-15 variant, which isolated from Klebsiella pneumoniae in a Chinese hospital, was a recently discovered KPC enzyme. To compare the characteristics of KPC-15 and KPC-2, the variants were determined by susceptibility testing, PCR amplification and sequencing, and study of kinetic parameters. The strain harboring the KPC-15 showed resistance to 18 co...

  15. From Genotype to Phenotype: Nonsense Variants in SLC13A1 Are Associated with Decreased Serum Sulfate and Increased Serum Aminotransferases

    Directory of Open Access Journals (Sweden)

    Christina G. Tise

    2016-09-01

    Full Text Available Using genomic applications to glean insights into human biology, we systematically searched for nonsense single nucleotide variants (SNVs that are rare in the general population but enriched in the Old Order Amish (Amish due to founder effect. We identified two nonlinked, nonsense SNVs (R12X and W48X in SLC13A1 (allele frequencies 0.29% and 0.74% in the Amish; enriched 1.2-fold and 3.7-fold, compared to the outbred Caucasian population, respectively. SLC13A1 encodes the apical sodium-sulfate cotransporter (NaS1 responsible for sulfate (reabsorption in the kidneys and intestine. SLC13A1 R12X and W48X were independently associated with a 27.6% (P = 2.7 × 10−8 and 27.3% (P = 6.9 × 10−14 decrease in serum sulfate, respectively (P = 8.8 × 10-20 for carriers of either SLC13A1 nonsense SNV. We further performed the first exome- and genome-wide association study (ExWAS/GWAS of serum sulfate and identified a missense variant (L348P in SLC26A1, which encodes the basolateral sulfate-anion transporter (Sat1, that was associated with decreased serum sulfate (P = 4.4 × 10−12. Consistent with sulfate’s role in xenobiotic detoxification and protection against acetaminophen-induced hepatotoxicity, SLC13A1 nonsense SNV carriers had higher aminotransferase levels compared to noncarriers. Furthermore, SLC26A1 L348P was associated with lower whole-body bone mineral density (BMD and higher serum calcium, consistent with the osteochondrodysplasia exhibited by dogs and sheep with naturally occurring, homozygous, loss-of-function mutations in Slc13a1. This study demonstrates the power and translational potential of systematic identification and characterization of rare, loss-of-function variants and warrants additional studies to better understand the importance of sulfate in human physiology, disease, and drug toxicity.

  16. Current conveyors variants, applications and hardware implementations

    CERN Document Server

    Senani, Raj; Singh, A K

    2015-01-01

    This book serves as a single-source reference to Current Conveyors and their use in modern Analog Circuit Design. The authors describe the various types of current conveyors discovered over the past 45 years, details of all currently available, off-the-shelf integrated circuit current conveyors, and implementations of current conveyors using other, off-the-shelf IC building blocks. Coverage includes prominent bipolar/CMOS/Bi-CMOS architectures of current conveyors, as well as all varieties of starting from third generation current conveyors to universal current conveyors, their implementations and applications. •Describes all commercially available off-the-shelf IC current conveyors, as well as hardware implementations of current conveyors using other off-the-shelf ICs; • Describes numerous variants of current conveyors evolved over the past forty five years; • Describes a number of Bipolar/CMOS/Bi-CMOS architectures of current conveyors, along with their characteristic features; • Includes a comprehe...

  17. Genetic variants in periodontal health and disease

    Energy Technology Data Exchange (ETDEWEB)

    Dumitrescu, Alexandrina L. [Tromsoe Univ. (Norway). Inst. of Clinical Dentistry; Kobayashi, Junya [Kyoto Univ. (Japan). Dept. of Genome Repair Dynamics

    2010-07-01

    Periodontitis is a complex, multifactorial disease and its susceptibility is genetically determined. The present book systematically reviews the evidence of the association between the genetic variants and periodontitis progression and/or treatment outcomes. Genetic syndromes known to be associated with periodontal disease, the candidate gene polymorphisms investigated in relation to periodontitis, the heritability of chronic and aggressive periodontitis, as well as common guidelines for association studies are described. This growing understanding of the role of genetic variation in inflammation and periodontal chronic disease presents opportunities to identify healthy persons who are at increased risk of disease and to potentially modify the trajectory of disease to prolong healthy aging. The book represents a new concept in periodontology with its pronounced focus on understanding through knowledge rather than presenting the presently valid answers. Connections between genetics and periodontology are systematically reviewed and covered in detail. (orig.)

  18. A look-ahead variant of TFQMR

    Energy Technology Data Exchange (ETDEWEB)

    Freund, R.W. [AT& T Bell Labs., Murray Hill, NJ (United States); Nachtigal, N.M. [Oak Ridge National Lab., TN (United States)

    1994-12-31

    Recently, Freund proposed a Krylov subspace iteration, the transpose-free quasi-minimal residual method (TFQMR), for solving general nonsingular non-Hermitian linear systems. The algorithm relies on a version of the squared Lanczos process to generate the basis vectors for the underlying Krylov subspace. It then constructs iterates defined by a quasi-minimization property, which leads to a smooth and nearly monotone convergence behavior. The authors investigate a variant of TFQMR that uses look-ahead to avoid some of the problems associated with breakdowns in the underlying squared Lanczos procedure. They also present some numerical examples that illustrate the properties of the new method, as compared to the original TFQMR algorithm.

  19. Genetic variants associated with lung function

    DEFF Research Database (Denmark)

    Thyagarajan, Bharat; Wojczynski, Mary; Minster, Ryan L

    2014-01-01

    BACKGROUND: Reduced forced expiratory volume in 1 second (FEV1) and the ratio of FEV1 to forced vital capacity (FVC) are strong predictors of mortality and lung function is higher among individuals with exceptional longevity. However, genetic factors associated with lung function in individuals...... with exceptional longevity have not been identified. METHOD: We conducted a genome wide association study (GWAS) to identify novel genetic variants associated with lung function in the Long Life Family Study (LLFS) (n = 3,899). Replication was performed using data from the CHARGE/SpiroMeta consortia...... used the residuals of the FEV1 and FEV1/FVC, adjusted for age, sex, height, ancestry principal components (PCs), smoking status, pack-years, and field center. RESULTS: We identified nine SNPs in strong linkage disequilibrium in the CYP2U1 gene to be associated with FEV1 and a novel SNP (rs889574...

  20. Some variants of SAT and their properties

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new model for the well-known problem, the satisfiablility problem of boolean formula (SAT), is introduced. Based on this model, some variants of SAT and their properties are presented. Denote by NP the class of all languages which can be decided by a non-deterministic polynomial Turing machine and by P the class of all languages which can be decided by a deterministic polynomial-time Turing machine. This model also allows us to give another candidate for the natural problems in ((NP-NPC)-P), denoted as NPI, under the assumption P≠NP, where NPC represents NP-complete. It is proven that this candidate is not in NPC under P≠NP. While, it is indeed in NPI under some stronger but reasonable assumption, specifically, under the Exponential-Time Hypothesis (ETH). Thus we can partially solve this long standing important open problem.

  1. Sturge -Weber Syndrome - Three Classic variants

    Directory of Open Access Journals (Sweden)

    R S Sathawane

    2006-01-01

    Full Text Available Sturge-Weber syndrome (SWS, also known as encephalotrigeminal angiomatosis, a sporadic, non-familial, congenital disorder consists of congenital hamartomatous malformations that may affect the eye, skin and central nervous system at different times. Sturge-Weber syndrome is classified as 1 Complete trisymptomatic: - when all three organ systems i.e. eye, skin and CNS are involved 2 Incomplete bisymptomatic:- when the involvement is either oculocutaneous or neurocutaneous, and 3 Incomplete monosymptomatic: when there is only neural or cutaneous involvement. Failure of proper vascular development is believed to be the most likely cause of this condition. The malformed blood vessels or hemangiomas may lead to port-wine stain, epilepsy and glaucoma depending on its location. Three classic variants with typical findings are discussed.

  2. Development of industrial variant specification systems

    DEFF Research Database (Denmark)

    Hansen, Benjamin Loer

    With globalisation and increased competition industrial companies must be prepared to satisfy individual customer needs and still stay competitive with regards to lead times, quality, and prices. These factors require companies to be better prepared to handle specification activities during order...... acquisition and order fulfilment, i.e. the creation of drawings, bill-of-materials, routings, product descriptions, quote letters etc. The present thesis is rooted in the assumption that variant specification systems supporting the cross-functional processes of order acquisition and order fulfilment must...... be developed from a holistic and strategically anchored point of view. Another assumption is that this is a challenge for many industrial companies. Even though the literature presents many considerations on general issues covering new information technology, little work is found on the business perspectives...

  3. Lipoleiomyoma: A rare variant of uterine leiomyoma

    Directory of Open Access Journals (Sweden)

    D Manimaran

    2014-01-01

    Full Text Available Uterine fatty tumors are rare variants of benign leiomyoma. Lipoleiomyoma, lipomyoma, fibromyolipoma are various synonyms for this lesion. They usually occur in the obese perimenopausal and postmenopausal females in the age group 50-70 years and 90% cases occur in patients older than 40 years. There were only few cases reported in the literature. These lesions are interesting due to the occasional diagnostic confusion with sarcomas and the curiosity regarding its histogenesis. We are presenting three cases of lipoleiomyoma whose age ranged from 40 to 50 years with clinical, radiologic and pathologic correlation. All three cases came with complaints of abnormal vaginal bleeding and found to have intramural heteroechoic nodule in the ultrasonogram.

  4. Probabilistic Transcriptome Assembly and Variant Graph Genotyping

    DEFF Research Database (Denmark)

    Sibbesen, Jonas Andreas

    the resulting sequencing data should be interpreted. This has over the years spurred the development of many probabilistic methods that are capable of modelling dierent aspects of the sequencing process. Here, I present two of such methods that were developed to each tackle a dierent problem in bioinformatics......, together with an application of the latter method to a large Danish sequencing project. The rst is a probabilistic method for transcriptome assembly that is based on a novel generative model of the RNA sequencing process and provides condence estimates on the assembled transcripts. We show...... that this approach outperforms existing state-of-the-art methods measured using sensitivity and precision on both simulated and real data. The second is a novel probabilistic method that uses exact alignment of k-mers to a set of variants graphs to provide unbiased estimates of genotypes in a population...

  5. Nuclear variants of bone morphogenetic proteins

    Directory of Open Access Journals (Sweden)

    Meinhart Christopher A

    2010-03-01

    Full Text Available Abstract Background Bone morphogenetic proteins (BMPs contribute to many different aspects of development including mesoderm formation, heart development, neurogenesis, skeletal development, and axis formation. They have previously been recognized only as secreted growth factors, but the present study detected Bmp2, Bmp4, and Gdf5/CDMP1 in the nuclei of cultured cells using immunocytochemistry and immunoblotting of nuclear extracts. Results In all three proteins, a bipartite nuclear localization signal (NLS was found to overlap the site at which the proproteins are cleaved to release the mature growth factors from the propeptides. Mutational analyses indicated that the nuclear variants of these three proteins are produced by initiating translation from downstream alternative start codons. The resulting proteins lack N-terminal signal peptides and are therefore translated in the cytoplasm rather than the endoplasmic reticulum, thus avoiding proteolytic processing in the secretory pathway. Instead, the uncleaved proteins (designated nBmp2, nBmp4, and nGdf5 containing the intact NLSs are translocated to the nucleus. Immunostaining of endogenous nBmp2 in cultured cells demonstrated that the amount of nBmp2 as well as its nuclear/cytoplasmic distribution differs between cells that are in M-phase versus other phases of the cell cycle. Conclusions The observation that nBmp2 localization varies throughout the cell cycle, as well as the conservation of a nuclear localization mechanism among three different BMP family members, suggests that these novel nuclear variants of BMP family proteins play an important functional role in the cell.

  6. New Variants of Ant Colony Optimization for Network Routing

    Directory of Open Access Journals (Sweden)

    Debasmita Mukherjee

    2012-12-01

    Full Text Available This paper suggests new variants of Ant Colony Optimization(ACOTechniques for Network Routing. There are three existing variants of ACO based on pheromone deposit calculation. In our earlier work we suggested three different heuristics for selecting the next node at each step of iteration. Incorporation of these heuristics in each of the above three variants result into nine variations. In this paper the performance of these nine variations has been studied. Moreover, we have modified the pheromone deposit calculation considering the transmission time of each successful packet(ant and incorporated this new pheromone update formula in each of the nine variants. As a result, we have obtained nine new variants of ACO. The performance of these new nine variants has been compared with previous ones with respect to the speed of execution, throughput and the number of successful packets. The experiments have been performed over two different network topologies. In one of the variant a tabu list has been incorporated. The length of the tabu list plays a vital role in improving the performance of the routing algorithm. In this paper it has been observed that the new variations of ACO have outperformed the previous ones. These new variants can perform efficient network routing in an environment having variable transmission time along the paths due to congestion or poor link quality.

  7. Managing Process Variants in the Process Life Cycle

    NARCIS (Netherlands)

    Hallerbach, A.; Bauer, Th.; Reichert, M.U.

    2007-01-01

    When designing process-aware information systems, often variants of the same process have to be specified. Each variant then constitutes an adjustment of a particular process to specific requirements building the process context. Current Business Process Management (BPM) tools do not adequately supp

  8. Assessment of Functional Effects of Unclassified Genetic Variants

    NARCIS (Netherlands)

    Couch, Fergus J.; Rasmussen, Lene Juel; Hofstra, Robert; Monteiro, Alvaro N. A.; Greenblatt, Marc S.; de Wind, Niels

    2008-01-01

    Inherited predisposition to disease is often linked to reduced activity of a disease associated gene product. Thus, quantitation of the influence of inherited variants on gene function can potentially be used to predict the disease relevance of these variants. While many disease genes have been exte

  9. Detecting rare variants in case-parents association studies.

    Directory of Open Access Journals (Sweden)

    Kuang-Fu Cheng

    Full Text Available Despite the success of genome-wide association studies (GWASs in detecting common variants (minor allele frequency ≥0.05 many suggested that rare variants also contribute to the genetic architecture of diseases. Recently, researchers demonstrated that rare variants can show a strong stratification which may not be corrected by using existing methods. In this paper, we focus on a case-parents study and consider methods for testing group-wise association between multiple rare (and common variants in a gene region and a disease. All tests depend on the numbers of transmitted mutant alleles from parents to their diseased children across variants and hence they are robust to the effect of population stratification. We use extensive simulation studies to compare the performance of four competing tests: the largest single-variant transmission disequilibrium test (TDT, multivariable test, combined TDT, and a likelihood ratio test based on a random-effects model. We find that the likelihood ratio test is most powerful in a wide range of settings and there is no negative impact to its power performance when common variants are also included in the analysis. If deleterious and protective variants are simultaneously analyzed, the likelihood ratio test was generally insensitive to the effect directionality, unless the effects are extremely inconsistent in one direction.

  10. Angiogenin variants in Parkinson disease and amyotrophic lateral sclerosis

    NARCIS (Netherlands)

    van Es, M.A.; Schelhaas, H.J.; van Vught, P.W.; Ticozzi, N.; Andersen, P.M.; Groen, E.J.; Schulte, C.; Blauw, H.M.; Koppers, M.; Diekstra, F.P.; Fumoto, K.; Leclerc, A.L.; Keagle, P.; Bloem, B.R.; Scheffer, H.; van Nuenen, B.F.; van Blitterswijk, M.; van Rheenen, W.; Wills, A.M.; Lowe, P.P.; Hu, G.F.; Yu, W.; Kishikawa, H.; Wu, D.; Folkerth, R.D.; Mariani, C.; Goldwurm, S.; Pezzoli, G.; van Damme, P.A.; Lemmens, R.; Dahlberg, C.; Birve, A.; Fernandez-Santiago, R.; Waibel, S.; Klein, C.; Weber, M.; van der Kooi, A.J.; de Visser, M.; Verbaan, D.; van Hilten, J.J.; Heutink, P.; Hennekam, E.A.; Cuppen, E.; Berg, D.; Brown Jr., R.H.; Silani, V.; Gasser, T.; Ludolph, A.C.; Robberecht, W.; Ophoff, R.A.; Veldink, J.H.; Pasterkamp, R.J.; Bakker, P.A.H.M.; Landers, J.E.; van de Warrenburg, B.P.; van den Berg, L.

    2011-01-01

    OBJECTIVE: Several studies have suggested an increased frequency of variants in the gene encoding angiogenin (ANG) in patients with amyotrophic lateral sclerosis (ALS). Interestingly, a few ALS patients carrying ANG variants also showed signs of Parkinson disease (PD). Furthermore, relatives of ALS

  11. Rare variants in PLXNA4 and Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Eva C Schulte

    Full Text Available Approximately 20% of individuals with Parkinson's disease (PD report a positive family history. Yet, a large portion of causal and disease-modifying variants is still unknown. We used exome sequencing in two affected individuals from a family with late-onset familial PD followed by frequency assessment in 975 PD cases and 1014 ethnically-matched controls and linkage analysis to identify potentially causal variants. Based on the predicted penetrance and the frequencies, a variant in PLXNA4 proved to be the best candidate and PLXNA4 was screened for additional variants in 862 PD cases and 940 controls, revealing an excess of rare non-synonymous coding variants in PLXNA4 in individuals with PD. Although we cannot conclude that the variant in PLXNA4 is indeed the causative variant, these findings are interesting in the light of a surfacing role of axonal guidance mechanisms in neurodegenerative disorders but, at the same time, highlight the difficulties encountered in the study of rare variants identified by next-generation sequencing in diseases with autosomal dominant or complex patterns of inheritance.

  12. The Structural Determinants behind the Epigenetic Role of Histone Variants

    Directory of Open Access Journals (Sweden)

    Manjinder S. Cheema

    2015-07-01

    Full Text Available Histone variants are an important part of the histone contribution to chromatin epigenetics. In this review, we describe how the known structural differences of these variants from their canonical histone counterparts impart a chromatin signature ultimately responsible for their epigenetic contribution. In terms of the core histones, H2A histone variants are major players while H3 variant CenH3, with a controversial role in the nucleosome conformation, remains the genuine epigenetic histone variant. Linker histone variants (histone H1 family haven’t often been studied for their role in epigenetics. However, the micro-heterogeneity of the somatic canonical forms of linker histones appears to play an important role in maintaining the cell-differentiated states, while the cell cycle independent linker histone variants are involved in development. A picture starts to emerge in which histone H2A variants, in addition to their individual specific contributions to the nucleosome structure and dynamics, globally impair the accessibility of linker histones to defined chromatin locations and may have important consequences for determining different states of chromatin metabolism.

  13. Association analysis identifies ZNF750 regulatory variants in psoriasis

    Directory of Open Access Journals (Sweden)

    Birnbaum Ramon Y

    2011-12-01

    Full Text Available Abstract Background Mutations in the ZNF750 promoter and coding regions have been previously associated with Mendelian forms of psoriasis and psoriasiform dermatitis. ZNF750 encodes a putative zinc finger transcription factor that is highly expressed in keratinocytes and represents a candidate psoriasis gene. Methods We examined whether ZNF750 variants were associated with psoriasis in a large case-control population. We sequenced the promoter and exon regions of ZNF750 in 716 Caucasian psoriasis cases and 397 Caucasian controls. Results We identified a total of 47 variants, including 38 rare variants of which 35 were novel. Association testing identified two ZNF750 haplotypes associated with psoriasis (p ZNF750 promoter and 5' UTR variants displayed a 35-55% reduction of ZNF750 promoter activity, consistent with the promoter activity reduction seen in a Mendelian psoriasis family with a ZNF750 promoter variant. However, the rare promoter and 5' UTR variants identified in this study did not strictly segregate with the psoriasis phenotype within families. Conclusions Two haplotypes of ZNF750 and rare 5' regulatory variants of ZNF750 were found to be associated with psoriasis. These rare 5' regulatory variants, though not causal, might serve as a genetic modifier of psoriasis.

  14. Hepatitis E Virus Variant in Farmed Mink, Denmark

    DEFF Research Database (Denmark)

    Krog, Jesper Schak; Breum, Solvej Østergaard; Jensen, Trine Hammer

    2013-01-01

    Hepatitis E virus (HEV) is a zoonotic virus for which pigs are the primary animal reservoir. To investigate whether HEV occurs in mink in Denmark, we screened feces and tissues from domestic and wild mink. Our finding of a novel HEV variant supports previous findings of HEV variants in a variety...

  15. Two new variants of the manifold-mapping technique

    NARCIS (Netherlands)

    Echeverria, D.

    2006-01-01

    Manifold-mapping is an efficient surrogate-based optimization technique aimed at the acceleration of very time-consuming design problems. In this paper we present two new variants of the original algorithm that make it applicable to a broader range of optimization scenarios. The first variant is use

  16. denovo-db: a compendium of human de novo variants.

    Science.gov (United States)

    Turner, Tychele N; Yi, Qian; Krumm, Niklas; Huddleston, John; Hoekzema, Kendra; F Stessman, Holly A; Doebley, Anna-Lisa; Bernier, Raphael A; Nickerson, Deborah A; Eichler, Evan E

    2017-01-04

    Whole-exome and whole-genome sequencing have facilitated the large-scale discovery of de novo variants in human disease. To date, most de novo discovery through next-generation sequencing focused on congenital heart disease and neurodevelopmental disorders (NDDs). Currently, de novo variants are one of the most significant risk factors for NDDs with a substantial overlap of genes involved in more than one NDD. To facilitate better usage of published data, provide standardization of annotation, and improve accessibility, we created denovo-db (http://denovo-db.gs.washington.edu), a database for human de novo variants. As of July 2016, denovo-db contained 40 different studies and 32,991 de novo variants from 23,098 trios. Database features include basic variant information (chromosome location, change, type); detailed annotation at the transcript and protein levels; severity scores; frequency; validation status; and, most importantly, the phenotype of the individual with the variant. We included a feature on our browsable website to download any query result, including a downloadable file of the full database with additional variant details. denovo-db provides necessary information for researchers to compare their data to other individuals with the same phenotype and also to controls allowing for a better understanding of the biology of de novo variants and their contribution to disease. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  17. Rare variants in XRCC2 as breast cancer susceptibility alleles

    NARCIS (Netherlands)

    Hilbers, F.S.; Wijnen, J.T.; Hoogerbrugge-van der Linden, N.; Oosterwijk, J.C.; Collee, M.J.; Peterlongo, P.; Radice, P.; Manoukian, S.; Feroce, I.; Capra, F.; Couch, F.J.; Wang, X.; Guidugli, L.; Offit, K.; Shah, S.; Campbell, I.G.; Thompson, E.R.; James, P.A.; Trainer, A.H.; Gracia, J.; Benitez, J.; Asperen, C.J. van; Devilee, P.

    2012-01-01

    BACKGROUND: Recently, rare germline variants in XRCC2 were detected in non-BRCA1/2 familial breast cancer cases, and a significant association with breast cancer was reported. However, the breast cancer risk associated with these variants needs further evaluation. METHODS: The coding regions and exo

  18. Isolation and characterization of human rhinovirus antigenic variants

    Energy Technology Data Exchange (ETDEWEB)

    Watson, D.G.

    1985-01-01

    Isolation of antigenic variants of human rhinovirus types 2, 14, and 17 was attempted by plaquing untreated virus (P-isolates), selecting variants in the presence of homologous antiserum (C-isolates), and by selecting variants in the presence of antibody following 5-fluorouracil mutagenesis (M-isolates). All viruses were triple-plaque purified and purity neutralization tested prior to isolate selection. Based on a fourfold reduction in neutralizing antibody titer to homologous antiserum, no antigenic variation was found in P-isolates from the three serotypes examined. Antigenic variants of all three serotypes could be isolated by the antiserum selection method (C-isolates). However, antigenic variants of RV17 were isolated at a much higher frequency and showed a larger degree of variation than those of RV2 and RV14. At least two of the variants selected, RV17 (C301) and RV2 (M803), failed to be neutralized by the known 89 rhinovirus antiserum. SDS-polyacrylamide gel electrophoresis of (/sup 35/S) methionine-labelled virion polypeptides revealed that each serotype had a characteristic pattern and that selected RV2 and RV17 isolates had patterns identical to those of the prototype strains. By isoelectric focusing an antigenic variant of RV2 was shown to contain altered virion polypeptides VP1 and VP2 whereas two RV17 antigenic variants demonstrated alterations only in the VP1 polypeptide.

  19. ADULT VARIANT BARTTER’S SYNDROME- A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Ishwar Sidappa Hasabi

    2017-02-01

    Full Text Available BACKGROUND Bartter syndrome is a group of channelopathies with different genetic origins and molecular pathophysiologies, but sharing common feature of decreased tubular transport of sodium chloride in thick ascending loop of Henle (TAL, 1 although more common in antenatal group. Classic adult variant of Bartter syndrome is a rare entity. We hereby present a rare adult variant of classic Bartter syndrome.

  20. Variant of Rett syndrome and CDKL5 gene

    DEFF Research Database (Denmark)

    Pini, Giorgio; Bigoni, Stefania; Engerström, Ingegerd Witt;

    2012-01-01

    UNLABELLED: Rett syndrome (RTT) is a severe neurodevelopmental disorder affecting almost exclusively females. The Hanefeld variant, or early-onset seizure variant, has been associated with mutations in CDKL5 gene. AIMS: In recent years more than 60 patients with mutations in the CDKL5 gene have b...

  1. Pathological assessment of mismatch repair gene variants in Lynch syndrome

    DEFF Research Database (Denmark)

    Rasmussen, Lene Juel; Heinen, Christopher D; Royer-Pokora, Brigitte;

    2012-01-01

    . Also, identifying family members that do not carry the variant is important so they can be released from the intensive surveillance. Determining which genetic variants are pathogenic and which are neutral is a major challenge in clinical genetics. The profound mechanistic knowledge on the genetics...

  2. Differential expression of Na+-K+-Cl- cotransporter 1 and K+-Cl- cotransporter 2 in the somata and dendrites of adult rat neocortical neurons[1]%NKCC1和KCC2在成年大鼠大脑皮质神经元的胞体和树突的不同表达

    Institute of Scientific and Technical Information of China (English)

    王德广

    2008-01-01

    γ-氨基丁酸(GABA)是成年哺乳动物脑内主要的抑制性神经递质,但电生理的研究表明,GABA在成熟皮质神经元的树突部位可以产生兴奋性作用,但该现象的形态学基础,目前尚不清楚.GABA产生兴奋性作用的关键主要依赖于神经元胞内的氰离子浓度,其中Na+-K-Cl-共转运体1(NKCC1)促进细胞内Cl-堆积,而K+-Cl-共转运体2(KCC2)则外排胞内的Cl-,降低胞内的Cl-浓度.本研究应用免疫荧光组织化学双重标记结合荧光强度分析,检测NKCC1和KCC2在成年大鼠脑皮质和培养的大鼠脑皮质神经元树突和胞体的表达和分布情况.结果显示:成年大鼠皮质神经元的胞浆和细胞膜均有NKCC1的表达,而KCC2主要表达在神经元胞体和树突膜上,其中NKCC1在神经元树突上的表达水平比胞体高.而KCC2的表达水平在树突和胞体膜上没有明显差异.皮质神经元经培养20 d后,NKCC1和KCC2在树突和胞体的表达模式与在体的分布相类似.本研究结果提示,NKCC1在大鼠皮质神经元树突的表达较多,可能是GABA兴奋神经元树突的原因.%γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the adult brain. However, electrophysiological findings indicate that GABA exerts excitation in dendrites of mature eorlieal neurons. Little is known about morphological basis of GABA-medi-ated excitation in dendrites of mature cortical neurons. The effect of activated GABAA receptors is mainly determined by intraceUular chloride ion, whose active influx is mainly mediated by Na+-K +-Cl- cotransporter isoform 1 (NKCC1) and exclusion is mainly executed by K+-Cl- cotransporter isoform 2 ( KCC2 ). In the present study, by using immunofluorescent double staining and fluorescent density analysis, the expression and distribution of NKCCI- and KCC2-immunoreactivities in the dendrite and soma of adult rat neocortical neurons were detected in vivo and in vitro. The present results showed that both

  3. Bayesian detection of causal rare variants under posterior consistency.

    KAUST Repository

    Liang, Faming

    2013-07-26

    Identification of causal rare variants that are associated with complex traits poses a central challenge on genome-wide association studies. However, most current research focuses only on testing the global association whether the rare variants in a given genomic region are collectively associated with the trait. Although some recent work, e.g., the Bayesian risk index method, have tried to address this problem, it is unclear whether the causal rare variants can be consistently identified by them in the small-n-large-P situation. We develop a new Bayesian method, the so-called Bayesian Rare Variant Detector (BRVD), to tackle this problem. The new method simultaneously addresses two issues: (i) (Global association test) Are there any of the variants associated with the disease, and (ii) (Causal variant detection) Which variants, if any, are driving the association. The BRVD ensures the causal rare variants to be consistently identified in the small-n-large-P situation by imposing some appropriate prior distributions on the model and model specific parameters. The numerical results indicate that the BRVD is more powerful for testing the global association than the existing methods, such as the combined multivariate and collapsing test, weighted sum statistic test, RARECOVER, sequence kernel association test, and Bayesian risk index, and also more powerful for identification of causal rare variants than the Bayesian risk index method. The BRVD has also been successfully applied to the Early-Onset Myocardial Infarction (EOMI) Exome Sequence Data. It identified a few causal rare variants that have been verified in the literature.

  4. Variante oncocítica del carcinoma mucoepidermoide Oncocyte variant of mucoepidermoid carcinoma

    Directory of Open Access Journals (Sweden)

    Sirced Salazar Rodríguez

    2011-03-01

    Full Text Available El carcinoma mucoepidermoide es el más común de todos los tumores malignos de glándulas salivales, constituye el 30 % de ellos. Aproximadamente la mitad de los casos (53 % ocurre en las glándulas salivales mayores. El 45 % predomina en glándula parótida, el 7 % en la submandibular y el 1 % en la glándula sublingual. Este tumor se presenta con más frecuencia en el sexo femenino (3:2 y en la quinta década de la vida. Múltiples variantes, con diferentes rangos de diferenciación han sido descritas, se incluyen: la oncocítica, esclerosante, uniquística, sebácea, de células claras, células globosas de alto grado, células fusocelular y psamomatosa. El carcinoma mucoepidermoide variante oncocítica es un subtipo raro que puede mostrar prominentes cambios oncocíticos. Se reporta un caso de carcinoma mucoepidermoide variante oncocítica de alto grado histológico. El índice de Ki 67 fue del 5 %, el tumor fue negativo para C-erb2 y presentó inmunorreactividad para E-caderina y Syndecan-1.The mucoepidermoid carcinoma is the commonest of all malignant tumors of salivary glands, accounting for the 30 % of them. Approximately the half of cases (53 % occurs in the major salivary glands. The 45 % has predominance in parotid gland, the 7 % in the submandibular one, and the 1 % in the sublingual gland one. This type of tumor is more frequent in female sex (3-2 and at fifth decade of life. Multiple variants with different ranks have been described including the oncocyte, sclerosant, unicystic, sebaceous, of clear cells, high degree spherical cells, fusocellular and psammomatous. The mucoepidermoid carcinoma, oncocyte variant, is an unusual subtype that may to shows significant oncocyte changes. Authors report a case of histological high degree mucoepidermoid carcinoma. The rate of Ki 67 was of 5 %, the negative tumor for C-erb2 and had immunoreaction to E-caderine and Syndecan-1.

  5. Meta-analysis of Gene-Level Associations for Rare Variants Based on Single-Variant Statistics

    NARCIS (Netherlands)

    Hu, Y.J.; Berndt, S.I.; Gustafsson, S.; Ganna, A.; Hirschhorn, J.; North, K.E.; Ingelsson, E.; Lin, D.Y.; Kiemeney, L.A.L.M.; Vermeulen, S.

    2013-01-01

    Meta-analysis of genome-wide association studies (GWASs) has led to the discoveries of many common variants associated with complex human diseases. There is a growing recognition that identifying "causal" rare variants also requires large-scale meta-analysis. The fact that association tests with rar

  6. Effects of hydrochlorothiazide on the pharmacokinetics, pharmacodynamics, and tolerability of canagliflozin, a sodium glucose co-transporter 2 inhibitor, in healthy participants.

    Science.gov (United States)

    Devineni, Damayanthi; Vaccaro, Nicole; Polidori, David; Rusch, Sarah; Wajs, Ewa

    2014-05-01

    Many patients with type 2 diabetes mellitus (T2DM) also have hypertension, which is commonly treated with thiazide diuretics, including hydrochlorothiazide (HCTZ). Canagliflozin, a sodium glucose cotransporter 2 inhibitor developed for the treatment of T2DM, lowers plasma glucose by inhibiting renal glucose reabsorption, thereby increasing urinary glucose excretion and mild osmotic diuresis. Because patients with T2DM are likely to receive concurrent canagliflozin and HCTZ, potential interactions were evaluated. This study evaluated the effects of HCTZ on the pharmacokinetic and pharmacodynamic properties and tolerability of canagliflozin in healthy participants. This Phase I, single-center, open-label, fixed-sequence, 2-period study was conducted in healthy participants. During period 1, participants received canagliflozin 300 mg once daily for 7 days, followed by a 14-day washout period. During period 2, participants received HCTZ 25 mg once daily for 28 days, followed by canagliflozin 300 mg + HCTZ 25 mg once daily for 7 days. Blood samples were taken before and several times after administration on day 7 of period 1 and on days 28 and 35 of period 2 for canagliflozin and HCTZ pharmacokinetic analyses using LC-MS/MS. Blood and urine samples were collected for up to 24 hours after canagliflozin administration on day 1 of period 1 and day 35 of period 2 for pharmacodynamic glucose assessment. Tolerability was also evaluated. Thirty participants were enrolled (16 men, 14 women; all white; mean age, 43.7 years). Canagliflozin AUC during a dosing interval (T) at steady state (AUCτ,ss) and Cmax at steady state (Cmax,ss) were increased when canagliflozin was coadministered with HCTZ, with geometric mean ratios (90% CI) of 1.12 (1.08-1.17) and 1.15 (1.06-1.25), respectively. AUCτ,ss and Cmax,ss for HCTZ were similar with and without canagliflozin coadministration. The 24-hour mean renal threshold for glucose and mean plasma glucose were comparable for canagliflozin

  7. αIIbβ3 variants defined by next-generation sequencing: Predicting variants likely to cause Glanzmann thrombasthenia

    Science.gov (United States)

    Buitrago, Lorena; Rendon, Augusto; Liang, Yupu; Simeoni, Ilenia; Negri, Ana; Filizola, Marta; Ouwehand, Willem H.; Coller, Barry S.; Alessi, Marie-Christine; Ballmaier, Matthias; Bariana, Tadbir; Bellissimo, Daniel; Bertoli, Marta; Bray, Paul; Bury, Loredana; Carrell, Robin; Cattaneo, Marco; Collins, Peter; French, Deborah; Favier, Remi; Freson, Kathleen; Furie, Bruce; Germeshausen, Manuela; Ghevaert, Cedric; Gomez, Keith; Goodeve, Anne; Gresele, Paolo; Guerrero, Jose; Hampshire, Dan J.; Hadinnapola, Charaka; Heemskerk, Johan; Henskens, Yvonne; Hill, Marian; Hogg, Nancy; Johnsen, Jill; Kahr, Walter; Kerr, Ron; Kunishima, Shinji; Laffan, Michael; Natwani, Amit; Neerman-Arbez, Marguerite; Nurden, Paquita; Nurden, Alan; Ormiston, Mark; Othman, Maha; Ouwehand, Willem; Perry, David; Vilk, Shoshana Ravel; Reitsma, Pieter; Rondina, Matthew; Simeoni, Ilenia; Smethurst, Peter; Stephens, Jonathan; Stevenson, William; Szkotak, Artur; Turro, Ernest; Van Geet, Christel; Vries, Minka; Ward, June; Waye, John; Westbury, Sarah; Whiteheart, Sidney; Wilcox, David; Zhang, Bi

    2015-01-01

    Next-generation sequencing is transforming our understanding of human genetic variation but assessing the functional impact of novel variants presents challenges. We analyzed missense variants in the integrin αIIbβ3 receptor subunit genes ITGA2B and ITGB3 identified by whole-exome or -genome sequencing in the ThromboGenomics project, comprising ∼32,000 alleles from 16,108 individuals. We analyzed the results in comparison with 111 missense variants in these genes previously reported as being associated with Glanzmann thrombasthenia (GT), 20 associated with alloimmune thrombocytopenia, and 5 associated with aniso/macrothrombocytopenia. We identified 114 novel missense variants in ITGA2B (affecting ∼11% of the amino acids) and 68 novel missense variants in ITGB3 (affecting ∼9% of the amino acids). Of the variants, 96% had minor allele frequencies (MAF) < 0.1%, indicating their rarity. Based on sequence conservation, MAF, and location on a complete model of αIIbβ3, we selected three novel variants that affect amino acids previously associated with GT for expression in HEK293 cells. αIIb P176H and β3 C547G severely reduced αIIbβ3 expression, whereas αIIb P943A partially reduced αIIbβ3 expression and had no effect on fibrinogen binding. We used receiver operating characteristic curves of combined annotation-dependent depletion, Polyphen 2-HDIV, and sorting intolerant from tolerant to estimate the percentage of novel variants likely to be deleterious. At optimal cut-off values, which had 69–98% sensitivity in detecting GT mutations, between 27% and 71% of the novel αIIb or β3 missense variants were predicted to be deleterious. Our data have implications for understanding the evolutionary pressure on αIIbβ3 and highlight the challenges in predicting the clinical significance of novel missense variants. PMID:25827233

  8. Physiology and pathophysiology of Na+/H+ exchange and Na+-K+-2Cl- cotransport in the heart, brain, and blood

    DEFF Research Database (Denmark)

    Pedersen, S. F.; O´Donnell, M. E.; Anderson, S. E.

    2006-01-01

    . The aim is to provide a comprehensive overview of the mechanisms and consequences of stress-induced stimulation of these transporters with focus on the heart, brain, and blood. The physiological stressors reviewed are metabolic/exercise stress, osmotic stress, and mechanical stress, conditions in which......Maintenance of a stable cell volume and intracellular pH is critical for normal cell function. Arguably, two of the most important ion transporters involved in these processes are the Na+/H+ exchanger isoform 1 (NHE1) and Na+-K+-2Cl- cotransporter isoform 1 (NKCC1). Both NHE1 and NKCC1...... are stimulated by cell shrinkage and by numerous other stimuli, including a wide range of hormones and growth factors, and for NHE1, intracellular acidification. Both transporters can be important regulators of cell volume, yet their activity also, directly or indirectly, affects the intracellular concentrations...

  9. Rare variant analysis for family-based design.

    Directory of Open Access Journals (Sweden)

    Gourab De

    Full Text Available Genome-wide association studies have been able to identify disease associations with many common variants; however most of the estimated genetic contribution explained by these variants appears to be very modest. Rare variants are thought to have larger effect sizes compared to common SNPs but effects of rare variants cannot be tested in the GWAS setting. Here we propose a novel method to test for association of rare variants obtained by sequencing in family-based samples by collapsing the standard family-based association test (FBAT statistic over a region of interest. We also propose a suitable weighting scheme so that low frequency SNPs that may be enriched in functional variants can be upweighted compared to common variants. Using simulations we show that the family-based methods perform at par with the population-based methods under no population stratification. By construction, family-based tests are completely robust to population stratification; we show that our proposed methods remain valid even when population stratification is present.

  10. Private mitochondrial DNA variants in danish patients with hypertrophic cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Christian M Hagen

    Full Text Available Hypertrophic cardiomyopathy (HCM is a genetic cardiac disease primarily caused by mutations in genes coding for sarcomeric proteins. A molecular-genetic etiology can be established in ~60% of cases. Evolutionarily conserved mitochondrial DNA (mtDNA haplogroups are susceptibility factors for HCM. Several polymorphic mtDNA variants are associated with a variety of late-onset degenerative diseases and affect mitochondrial function. We examined the role of private, non-haplogroup associated, mitochondrial variants in the etiology of HCM. In 87 Danish HCM patients, full mtDNA sequencing revealed 446 variants. After elimination of 312 (69.9% non-coding and synonymous variants, a further 109 (24.4% with a global prevalence > 0.1%, three (0.7% haplogroup associated and 19 (2.0% variants with a low predicted in silico likelihood of pathogenicity, three variants: MT-TC: m.5772G>A, MT-TF: m.644A>G, and MT-CYB: m.15024G>A, p.C93Y remained. A detailed analysis of these variants indicated that none of them are likely to cause HCM. In conclusion, private mtDNA mutations are frequent, but they are rarely, if ever, associated with HCM.

  11. Sialyloligosaccharide receptors of binding variants of polyoma virus.

    Science.gov (United States)

    Cahan, L D; Singh, R; Paulson, J C

    1983-10-30

    Hemagglutination and lytic infection of host cells by polyoma virus has been shown to require specific sialyloligosaccharide structures. The nature of the sialyloligosaccharide sequence recognized by three binding variants of polyoma virus, the large plaque (LP), small plaque (SP), and Py235 variants, was examined. Hemagglutination of native erythrocytes and erythrocytes derivatized with highly specific sialyltransferases to contain cell surface sialyloligosaccharides of defined sequence was compared for the three variants. In addition, soluble glycoprotein inhibitors of known sialyloligosaccharide structure were used to further elucidate the specificities of the three variants. There are important differences in the receptors for these variants. While all three appear to bind the structure NeuAc alpha 2,3Gal beta 1,3GalNAc the LP and Py235 variant bind the disialyl structure NeuAc alpha 2,3Gal beta 1,3(NeuAc alpha 2,6)GalNAc with much lower affinity than does the SP virus. It is suggested that polyoma virus adsorption to cells may depend on the cell surface content of at least three different sialyloligosaccharide sequences and the relative abilities of the virus variant to utilize them as receptor determinants.

  12. How important are rare variants in common disease?

    Science.gov (United States)

    Saint Pierre, Aude; Génin, Emmanuelle

    2014-09-01

    Genome-wide association studies have uncovered hundreds of common genetic variants involved in complex diseases. However, for most complex diseases, these common genetic variants only marginally contribute to disease susceptibility. It is now argued that rare variants located in different genes could in fact play a more important role in disease susceptibility than common variants. These rare genetic variants were not captured by genome-wide association studies using single nucleotide polymorphism-chips but with the advent of next-generation sequencing technologies, they have become detectable. It is now possible to study their contribution to common disease by resequencing samples of cases and controls or by using new genotyping exome arrays that cover rare alleles. In this review, we address the question of the contribution of rare variants in common disease by taking the examples of different diseases for which some resequencing studies have already been performed, and by summarizing the results of simulation studies conducted so far to investigate the genetic architecture of complex traits in human. So far, empirical data have not allowed the exclusion of many models except the most extreme ones involving only a small number of rare variants with large effects contributing to complex disease. To unravel the genetic architecture of complex disease, case-control data will not be sufficient, and alternative study designs need to be proposed together with methodological developments.

  13. The Clinical Significance of Unknown Sequence Variants in BRCA Genes

    Energy Technology Data Exchange (ETDEWEB)

    Calò, Valentina; Bruno, Loredana; Paglia, Laura La; Perez, Marco; Margarese, Naomi [Department of Surgery and Oncology, Regional Reference Center for the Biomolecular Characterization and Genetic Screening of Hereditary Tumors, University of Palermo, Via del Vespro 127, 90127 Palermo (Italy); Gaudio, Francesca Di [Department of Medical Biotechnologies and Legal Medicine, University of Palermo, Palermo (Italy); Russo, Antonio, E-mail: lab-oncobiologia@usa.net [Department of Surgery and Oncology, Regional Reference Center for the Biomolecular Characterization and Genetic Screening of Hereditary Tumors, University of Palermo, Via del Vespro 127, 90127 Palermo (Italy)

    2010-09-10

    Germline mutations in BRCA1/2 genes are responsible for a large proportion of hereditary breast and/or ovarian cancers. Many highly penetrant predisposition alleles have been identified and include frameshift or nonsense mutations that lead to the translation of a truncated protein. Other alleles contain missense mutations, which result in amino acid substitution and intronic variants with splicing effect. The discovery of variants of uncertain/unclassified significance (VUS) is a result that can complicate rather than improve the risk assessment process. VUSs are mainly missense mutations, but also include a number of intronic variants and in-frame deletions and insertions. Over 2,000 unique BRCA1 and BRCA2 missense variants have been identified, located throughout the whole gene (Breast Cancer Information Core Database (BIC database)). Up to 10–20% of the BRCA tests report the identification of a variant of uncertain significance. There are many methods to discriminate deleterious/high-risk from neutral/low-risk unclassified variants (i.e., analysis of the cosegregation in families of the VUS, measure of the influence of the VUSs on the wild-type protein activity, comparison of sequence conservation across multiple species), but only an integrated analysis of these methods can contribute to a real interpretation of the functional and clinical role of the discussed variants. The aim of our manuscript is to review the studies on BRCA VUS in order to clarify their clinical relevance.

  14. Identification of copy number variants in horses

    KAUST Repository

    Doan, R.

    2012-03-01

    Copy number variants (CNVs) represent a substantial source of genetic variation in mammals. However, the occurrence of CNVs in horses and their subsequent impact on phenotypic variation is unknown. We performed a study to identify CNVs in 16 horses representing 15 distinct breeds (Equus caballus) and an individual gray donkey (Equus asinus) using a whole-exome tiling array and the array comparative genomic hybridization methodology. We identified 2368 CNVs ranging in size from 197 bp to 3.5 Mb. Merging identical CNVs from each animal yielded 775 CNV regions (CNVRs), involving 1707 protein- and RNA-coding genes. The number of CNVs per animal ranged from 55 to 347, with median and mean sizes of CNVs of 5.3 kb and 99.4 kb, respectively. Approximately 6% of the genes investigated were affected by a CNV. Biological process enrichment analysis indicated CNVs primarily affected genes involved in sensory perception, signal transduction, and metabolism. CNVs also were identified in genes regulating blood group antigens, coat color, fecundity, lactation, keratin formation, neuronal homeostasis, and height in other species. Collectively, these data are the first report of copy number variation in horses and suggest that CNVs are common in the horse genome and may modulate biological processes underlying different traits observed among horses and horse breeds.

  15. Probabilistic Transcriptome Assembly and Variant Graph Genotyping

    DEFF Research Database (Denmark)

    Sibbesen, Jonas Andreas

    The introduction of second-generation sequencing, has in recent years allowed the biological community to determine the genomes and transcriptomes of organisms and individuals at an unprecedented rate. However, almost every step in the sequencing protocol introduces uncertainties in how the resul......The introduction of second-generation sequencing, has in recent years allowed the biological community to determine the genomes and transcriptomes of organisms and individuals at an unprecedented rate. However, almost every step in the sequencing protocol introduces uncertainties in how...... the resulting sequencing data should be interpreted. This has over the years spurred the development of many probabilistic methods that are capable of modelling dierent aspects of the sequencing process. Here, I present two of such methods that were developed to each tackle a dierent problem in bioinformatics...... that this approach outperforms existing state-of-the-art methods measured using sensitivity and precision on both simulated and real data. The second is a novel probabilistic method that uses exact alignment of k-mers to a set of variants graphs to provide unbiased estimates of genotypes in a population...

  16. CRY2 genetic variants associate with dysthymia.

    Directory of Open Access Journals (Sweden)

    Leena Kovanen

    Full Text Available People with mood disorders often have disruptions in their circadian rhythms. Recent molecular genetics has linked circadian clock genes to mood disorders. Our objective was to study two core circadian clock genes, CRY1 and CRY2 as well as TTC1 that interacts with CRY2, in relation to depressive and anxiety disorders. Of these three genes, 48 single-nucleotide polymorphisms (SNPs whose selection was based on the linkage disequilibrium and potential functionality were genotyped in 5910 individuals from a nationwide population-based sample. The diagnoses of major depressive disorder, dysthymia and anxiety disorders were assessed with a structured interview (M-CIDI. In addition, the participants filled in self-report questionnaires on depressive and anxiety symptoms. Logistic and linear regression models were used to analyze the associations of the SNPs with the phenotypes. Four CRY2 genetic variants (rs10838524, rs7121611, rs7945565, rs1401419 associated significantly with dysthymia (false discovery rate q<0.05. This finding together with earlier CRY2 associations with winter depression and with bipolar type 1 disorder supports the view that CRY2 gene has a role in mood disorders.

  17. Human papillomavirus type-16 variants in Quechua aboriginals from Argentina.

    Science.gov (United States)

    Picconi, María Alejandra; Alonio, Lidia Virginia; Sichero, Laura; Mbayed, Viviana; Villa, Luisa Lina; Gronda, Jorge; Campos, Rodolfo; Teyssié, Angélica

    2003-04-01

    Cervical carcinoma is the leading cause of cancer death in Quechua indians from Jujuy (northwestern Argentina). To determine the prevalence of HPV-16 variants, 106 HPV-16 positive cervical samples were studied, including 33 low-grade squamous intraepithelial lesions (LSIL), 28 high-grade squamous intraepithelial lesions (HSIL), 9 invasive cervical cancer (ICC), and 36 samples from women with normal colposcopy and cytology. HPV genome variability was examined in the L1 and E6 genes by PCR-hybridization. In a subset of 20 samples, a LCR fragment was also analyzed by PCR-sequencing. Most variants belonged to the European branch with subtle differences that depended on the viral gene fragment studied. Only about 10% of the specimens had non-European variants, including eight Asian-American, two Asian, and one North-American-1. E6 gene analysis revealed that 43% of the samples were identical to HPV-16 prototype, while 57% corresponded to variants. Interestingly, the majority (87%) of normal smears had HPV-16 prototype, whereas variants were detected mainly in SIL and ICC. LCR sequencing yielded 80% of variants, including 69% of European, 19% Asian-American, and 12% Asian. We identified a new variant, the Argentine Quechua-51 (AQ-51), similar to B-14 plus two additional changes: G7842-->A and A7837-->C; phylogenetic inference allocated it in the Asian-American branch. The high proportion of European variants may reflect Spanish colonial influence on these native Inca descendants. The predominance of HPV-16 variants in pathologic samples when compared to normal controls could have implications for the natural history of cervical lesions.

  18. Migraine variants--occurrence in pediatric neurology practice.

    Science.gov (United States)

    Pacheva, Iliyana H; Ivanov, Ivan S

    2013-09-01

    Migraine is common in pediatric neurology practice, while migraine variants are rare and pose diagnostic problems. The aim was to establish the occurrence of migraine variants in pediatric neurology practice and among migraine, and to discuss their presentation. The files of 2509 newly diagnosed patients, aged 0-18 years, treated as in- and out-patients in the Neuropediatric Ward at the Plovdiv Medical University Hospital between 2002 and 2006 were examined retrospectively. Migraine forms were diagnosed according to ICHD-II. Benign paroxysmal torticolis and alternating hemiplegia of childhood were also accepted as migraine variants according to proposed diagnostic criteria in the appendix of ICHD-II. Some specific forms like acute confusional migraine (ACM), Alice in wonderland syndrome (AWS), ophthalmoplegic migraine were also diagnosed although not included as migraine variants in the ICHD-II classification. 111 patients met diagnostic criteria for migraine. Patients with migraine variants comprised 24.3% of migrainous cases. Basilar type migraine was the most common (6.3% of all migrainous patients), followed by benign paroxysmal vertigo (5.4%), hemiplegic migraine (3.6%), ACM (2.7%), benign paroxysmal torticolis (2.7%), typical aura without headache (1.8%), abdominal migraine (1.8%), AWS (0.9%), ophthalmoplegic migraine (0.9%) and cyclical vomiting (0.9%). Alternating hemiplegia of childhood and retinal migraine was not found. Some patients either presented or were classified as different migraine variants. Basilar type migraine was the most common migraine variant. ACM and AWS should be regarded as distinct entities in the ICHD as migraine with complex aura. Benign paroxysmal torticollis also deserves its place as a migraine variant. Cases of ophthalmoplegic migraine with spontaneous remission and no cranial nerve enhancement on MRI should be considered as migraine form. Analyzing migraine variants will contribute to better awareness and adequate diagnosis

  19. Inactivation of the Na-Cl co-transporter (NCC) gene is associated with high BMD through both renal and bone mechanisms: analysis of patients with Gitelman syndrome and Ncc null mice.

    Science.gov (United States)

    Nicolet-Barousse, Laurence; Blanchard, Anne; Roux, Christian; Pietri, Laurence; Bloch-Faure, May; Kolta, Sami; Chappard, Christine; Geoffroy, Valérie; Morieux, Caroline; Jeunemaitre, Xavier; Shull, Gary E; Meneton, Pierre; Paillard, Michel; Houillier, Pascal; De Vernejoul, Marie-Christine

    2005-05-01

    Chronic thiazide treatment is associated with high BMD. We report that patients and mice with null mutations in the thiazide-sensitive NaCl cotransporter (NCC) have higher renal tubular Ca reabsorption, higher BMD, and lower bone remodeling than controls, as well as abnormalities in Ca metabolism, mainly caused by Mg depletion. Chronic thiazide treatment decreases urinary Ca excretion (UVCa) and increases BMD. To understand the underlying mechanisms, Ca and bone metabolism were studied in two models of genetic inactivation of the thiazide-sensitive NaCl cotransporter (NCC): patients with Gitelman syndrome (GS) and Ncc knockout (Ncc(-/-)) mice. Ca metabolism was analyzed in GS patients and Ncc(-/-) mice under conditions of low dietary Ca. BMD was measured by DXA in patients and mice, and bone histomorphometry was analyzed in mice. GS patients had low plasma Mg. They exhibited reduced UVCa, but similar serum Ca and GFR as control subjects, suggesting increased renal Ca reabsorption. Blood PTH was lower despite lower serum ionized Ca, and Mg repletion almost corrected both relative hypoparathyroidism and low UVCa. BMD was significantly increased in GS patients at both lumbar (+7%) and femoral (+16%) sites, and osteocalcin was reduced. In Ncc(-/-) mice, serum Ca and GFR were unchanged, but UVCa was reduced and PTH was elevated; Mg repletion largely corrected both abnormalities. Trabecular and cortical BMD were higher than in Ncc(+/+) mice (+4% and +5%, respectively), and despite elevated PTH, were associated with higher cortical thickness and lower endosteal osteoclastic surface. Higher BMD is observed in GS patients and Ncc(-/-) mice. Relative hypoparathyroidism (human) and bone resistance to PTH (mice), mainly caused by Mg depletion, can explain the low bone remodeling and normal/low serum Ca despite increased renal Ca reabsorption.

  20. Geometric Structures of Stable Time-Variant State Feedback Systems

    Institute of Scientific and Technical Information of China (English)

    ZHONG Feng-wei; SUN Hua-fei; ZHANG Zhen-ning

    2007-01-01

    A new technique for considering the stabilizing time-variant state feedback gains is proposed from the viewpoint of information geometry. First, parametrization of the set of all stabilizing time-variant state feedback gains is given. Moreover, a diffeomorphic structure between the set of stabilizing time-variant state feedback gains and the Cartesian product of positive definite matrix and skew symmetric matrix satisfying certain algebraic conditions is constructed. Furth ermore, an immersion and some results about the eigenvalue locations of stable state feedback systems are derived.

  1. De Novo Coding Variants Are Strongly Associated with Tourette Disorder

    DEFF Research Database (Denmark)

    Willsey, A Jeremy; Fernandez, Thomas V; Yu, Dongmei

    2017-01-01

    Whole-exome sequencing (WES) and de novo variant detection have proven a powerful approach to gene discovery in complex neurodevelopmental disorders. We have completed WES of 325 Tourette disorder trios from the Tourette International Collaborative Genetics cohort and a replication sample of 186...... trios from the Tourette Syndrome Association International Consortium on Genetics (511 total). We observe strong and consistent evidence for the contribution of de novo likely gene-disrupting (LGD) variants (rate ratio [RR] 2.32, p = 0.002). Additionally, de novo damaging variants (LGD and probably...

  2. The role of common genetic variants in atrial fibrillation

    DEFF Research Database (Denmark)

    Paludan-Muller, Christian; Svendsen, Jesper H.; Olesen, Morten S.

    2016-01-01

    this approach. Highly penetrant variants in lone AF have also been described in a number of cases. Furthermore, familial AF, although rare, have been recognized for many years. Variants associated with AF have been identified in more than 40 genes, including cardiac gap junction proteins, ion channels and beta......This review focuses on the genetic basis of atrial fibrillation (AF) and the role of variants in the susceptibility of developing the disease. AF is the most common cardiac arrhythmia affecting 1-2% of the general population. Studies in the last decade have demonstrated that AF, and in particular...... and non-cardiac diseases....

  3. Variante de Dandy Walker: relato de caso = Dandy Walker variant: a case report

    Directory of Open Access Journals (Sweden)

    Khan, Richard Lester et al.

    2009-01-01

    Full Text Available Objetivos: relatar o caso de um paciente com variante de Dandy Walker, chamando atenção para a importância da suspeita, investigação e manejo das repercussões clínicas. Descrição do caso: é relatado o caso de um paciente do sexo masculino, com quadro clínico e radiológico típico da Variante de Dandy Walker. Durante o pré-natal, através de ecografia obstétrica com 23 semanas e 3 dias, apresentou alterações sugestivas de Síndrome de Dandy Walker. Ao nascimento apresentou exame físico com fenda palatina, criptorquidia à direita, hexodactilia em ambos os pés. Apresentava ainda ecocardiograma com forame oval patente e persistência do canal arterial. O diagnóstico foi estabelecido através da ressonância magnética realizada após o nascimento, que evidenciava hipoplasia do vermis cerebelar, alargamento da fossa posterior e leve dilatação ventricular. Conclusões: este artigo procura caracterizar a variante de Dandy Walker, que é uma malformação congênita do sistema nervoso central e é o tipo mais comum da Síndrome de Dandy Walker. Seu fenótipo é variável, devendo-se sempre pesquisar malformações tanto intra quanto extracranianas, visto que o risco de mortalidade pós-natal aumenta quando existe esta associação. O tratamento envolve equipe multidisciplinar e o prognóstico é reservado, variando conforme o fenótipo.

  4. Variant Boussinesq方程组的精确解%Exact Solutions for Variant Boussinesq Equations

    Institute of Scientific and Technical Information of China (English)

    吴世旭

    2009-01-01

    F-展开法是近年提出的求非线性偏微分方程的精确解的一种简单而有效的方法.本文运用改进的F-展开法寻求Variant Boussinesq方程组的行波解,得到了该方程组多种类型的精确解,包括Jacobi椭圆函数解、孤立波解、三角函数解和有理函数解.

  5. Hierarchical generalized linear models for multiple groups of rare and common variants: jointly estimating group and individual-variant effects.

    Directory of Open Access Journals (Sweden)

    Nengjun Yi

    2011-12-01

    Full Text Available Complex diseases and traits are likely influenced by many common and rare genetic variants and environmental factors. Detecting disease susceptibility variants is a challenging task, especially when their frequencies are low and/or their effects are small or moderate. We propose here a comprehensive hierarchical generalized linear model framework for simultaneously analyzing multiple groups of rare and common variants and relevant covariates. The proposed hierarchical generalized linear models introduce a group effect and a genetic score (i.e., a linear combination of main-effect predictors for genetic variants for each group of variants, and jointly they estimate the group effects and the weights of the genetic scores. This framework includes various previous methods as special cases, and it can effectively deal with both risk and protective variants in a group and can simultaneously estimate the cumulative contribution of multiple variants and their relative importance. Our computational strategy is based on extending the standard procedure for fitting generalized linear models in the statistical software R to the proposed hierarchical models, leading to the development of stable and flexible tools. The methods are illustrated with sequence data in gene ANGPTL4 from the Dallas Heart Study. The performance of the proposed procedures is further assessed via simulation studies. The methods are implemented in a freely available R package BhGLM (http://www.ssg.uab.edu/bhglm/.

  6. Hierarchical Generalized Linear Models for Multiple Groups of Rare and Common Variants: Jointly Estimating Group and Individual-Variant Effects

    Science.gov (United States)

    Yi, Nengjun; Liu, Nianjun; Zhi, Degui; Li, Jun

    2011-01-01

    Complex diseases and traits are likely influenced by many common and rare genetic variants and environmental factors. Detecting disease susceptibility variants is a challenging task, especially when their frequencies are low and/or their effects are small or moderate. We propose here a comprehensive hierarchical generalized linear model framework for simultaneously analyzing multiple groups of rare and common variants and relevant covariates. The proposed hierarchical generalized linear models introduce a group effect and a genetic score (i.e., a linear combination of main-effect predictors for genetic variants) for each group of variants, and jointly they estimate the group effects and the weights of the genetic scores. This framework includes various previous methods as special cases, and it can effectively deal with both risk and protective variants in a group and can simultaneously estimate the cumulative contribution of multiple variants and their relative importance. Our computational strategy is based on extending the standard procedure for fitting generalized linear models in the statistical software R to the proposed hierarchical models, leading to the development of stable and flexible tools. The methods are illustrated with sequence data in gene ANGPTL4 from the Dallas Heart Study. The performance of the proposed procedures is further assessed via simulation studies. The methods are implemented in a freely available R package BhGLM (http://www.ssg.uab.edu/bhglm/). PMID:22144906

  7. Meta-analysis of gene-level associations for rare variants based on single-variant statistics.

    Science.gov (United States)

    Hu, Yi-Juan; Berndt, Sonja I; Gustafsson, Stefan; Ganna, Andrea; Hirschhorn, Joel; North, Kari E; Ingelsson, Erik; Lin, Dan-Yu

    2013-08-08

    Meta-analysis of genome-wide association studies (GWASs) has led to the discoveries of many common variants associated with complex human diseases. There is a growing recognition that identifying "causal" rare variants also requires large-scale meta-analysis. The fact that association tests with rare variants are performed at the gene level rather than at the variant level poses unprecedented challenges in the meta-analysis. First, different studies may adopt different gene-level tests, so the results are not compatible. Second, gene-level tests require multivariate statistics (i.e., components of the test statistic and their covariance matrix), which are difficult to obtain. To overcome these challenges, we propose to perform gene-level tests for rare variants by combining the results of single-variant analysis (i.e., p values of association tests and effect estimates) from participating studies. This simple strategy is possible because of an insight that multivariate statistics can be recovered from single-variant statistics, together with the correlation matrix of the single-variant test statistics, which can be estimated from one of the participating studies or from a publicly available database. We show both theoretically and numerically that the proposed meta-analysis approach provides accurate control of the type I error and is as powerful as joint analysis of individual participant data. This approach accommodates any disease phenotype and any study design and produces all commonly used gene-level tests. An application to the GWAS summary results of the Genetic Investigation of ANthropometric Traits (GIANT) consortium reveals rare and low-frequency variants associated with human height. The relevant software is freely available.

  8. Myostatin: genetic variants, therapy and gene doping

    Directory of Open Access Journals (Sweden)

    André Katayama Yamada

    2012-09-01

    Full Text Available Since its discovery, myostatin (MSTN has been at the forefront of muscle therapy research because intrinsic mutations or inhibition of this protein, by either pharmacological or genetic means, result in muscle hypertrophy and hyperplasia. In addition to muscle growth, MSTN inhibition potentially disturbs connective tissue, leads to strength modulation, facilitates myoblast transplantation, promotes tissue regeneration, induces adipose tissue thermogenesis and increases muscle oxidative phenotype. It is also known that current advances in gene therapy have an impact on sports because of the illicit use of such methods. However, the adverse effects of these methods, their impact on athletic performance in humans and the means of detecting gene doping are as yet unknown. The aim of the present review is to discuss biosynthesis, genetic variants, pharmacological/genetic manipulation, doping and athletic performance in relation to the MSTN pathway. As will be concluded from the manuscript, MSTN emerges as a promising molecule for combating muscle wasting diseases and for triggering wide-ranging discussion in view of its possible use in gene doping.Desde sua descoberta, a miostatina (MSTN entrou na linha de frente em pesquisas relacionadas às terapias musculares porque mutações intrínsecas ou inibição desta proteína tanto por abordagens farmacológicas como genéticas resultam em hipertrofia muscular e hiperplasia. Além do aumento da massa muscular, a inibição de MSTN potencialmente prejudica o tecido conectivo, modula a força muscular, facilita o transplante de mioblastos, promove regeneração tecidual, induz termogênese no tecido adiposo e aumenta a oxidação na musculatura esquelética. É também sabido que os atuais avanços em terapia gênica têm uma relação com o esporte devido ao uso ilícito de tal método. Os efeitos adversos de tal abordagem, seus efeitos no desempenho de atletas e métodos para detectar doping genético s

  9. Study on Variant Anatomy of Sciatic Nerve

    Science.gov (United States)

    V, Sangeetha

    2014-01-01

    Introduction: Sciatic Nerve (SN) is the nerve of the posterior compartment of thigh formed in the pelvis from the ventral rami of the L4 to S3 spinal nerves. It leaves the pelvis via the greater sciatic foramen below piriformis and divides into Common Peroneal Nerve (CPN) and Tibial Nerve (TN) at the level of the upper angle of the popliteal fossa. Higher division of the sciatic nerve is the most common variation where the TN and CPN may leave the pelvis through different routes. Such variation may lead to compression of the nerve and lead to Non-discogenic sciatica. Materials and Methods: Fifty lower limbs were used for the study from Department of Anatomy, J.J.M.M.C Davangere, Karnataka, India. Observation and Results: In our study on 25 cadavers (50 lower limbs), we have observed 4 (8 %) lower limbs high division of sciatic nerve was noted. High division of sciatic nerve in the back of thigh was noted in one specimen (2%), while high division within the pelvis was noted in 3 specimens (6%), while in 46 (92%) it occurred outside the pelvis. Conclusion: Knowledge regarding such variation and differences in the course of SN is important for the surgeons to plan for various surgical interventions pertaining to the gluteal region. The variant anatomy of SN may cause piriformis syndrome and failure of SN block. Hence present study is undertaken to know the level of division, exit, course, relationship to piriformis and variations in the branching pattern of SN. PMID:25302181

  10. Common Gene Variants Account for Most Genetic Risk for Autism

    Science.gov (United States)

    ... July 20, 2014 Common gene variants account for most genetic risk for autism Roles of heritability, mutations, ... factors. Population-Based Autism Genetics and Environment Study Most of the genetic risk for autism comes from ...

  11. Variant Plasmodium ovale isolated from a patient infected in Ghana

    Directory of Open Access Journals (Sweden)

    Petersen Eskild

    2011-01-01

    Full Text Available Abstract Recent data have found that Plasmodium ovale can be separated in two distinct species: classic and variant P. ovale based on multilocus typing of different genes. This study presents a P. ovale isolate from a patient infected in Ghana together with an analysis of the small subunit RNA, cytochrome b, cytochrome c oxidase I, cysteine protease and lactate dehydrogenase genes, which show that the sample is a variant P. ovale and identical or highly similar to variant P. ovale isolated from humans in South-East Asia and Africa, and from a chimpanzee in Cameroon. The split between the variant and classic P. ovale is estimated to have occurred 1.7 million years ago.

  12. Differential protein expression in phenotypic variants of Streptococcus pneumoniae

    NARCIS (Netherlands)

    K. Overweg (Karin); C.D. Pericone; G.G. Verhoef; J.N. Weiser; H.D. Meiring; A.P. de Jong; R. de Groot (Ronald); P.W.M. Hermans (Peter)

    2000-01-01

    textabstractStreptococcus pneumoniae undergoes spontaneous phase variation resulting in opaque and transparent colony forms. Differences in colony opacity correlate with differences in virulence: the transparent variants are more capable of colonizing the nasopharynx, w

  13. Neuropathology in classical and variant ataxia-telangiectasia.

    NARCIS (Netherlands)

    Verhagen, M.M.M.; Martin, J.J.; Deuren, M. van; Ceuterick-de Groote, C.; Weemaes, C.M.R.; Kremer, B.; Taylor, M.A.; Willemsen, M.A.A.P.; Lammens, M.M.Y.

    2012-01-01

    Ataxia-telangiectasia (A-T) is classically characterized by progressive neurodegeneration, oculocutaneous telangiectasia, immunodeficiency and elevated alpha-fetoprotein levels. Some patients, classified as variant A-T, exhibit a milder clinical course. In the latter patients extrapyramidal symptoms

  14. Method of generating ploynucleotides encoding enhanced folding variants

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, Andrew M.; Kiss, Csaba; Waldo, Geoffrey S.

    2017-05-02

    The invention provides directed evolution methods for improving the folding, solubility and stability (including thermostability) characteristics of polypeptides. In one aspect, the invention provides a method for generating folding and stability-enhanced variants of proteins, including but not limited to fluorescent proteins, chromophoric proteins and enzymes. In another aspect, the invention provides methods for generating thermostable variants of a target protein or polypeptide via an internal destabilization baiting strategy. Internally destabilization a protein of interest is achieved by inserting a heterologous, folding-destabilizing sequence (folding interference domain) within DNA encoding the protein of interest, evolving the protein sequences adjacent to the heterologous insertion to overcome the destabilization (using any number of mutagenesis methods), thereby creating a library of variants. The variants in the library are expressed, and those with enhanced folding characteristics selected.

  15. Behavioral variant of frontotemporal dementia mimicking Huntington's disease

    DEFF Research Database (Denmark)

    Nielsen, T Rune; Bruhn, Peter; Nielsen, Jørgen E

    2010-01-01

    Behavioral changes and cognitive decline are the core clinical manifestations in the behavioral variant of frontotemporal dementia (bv-FTD). The behavioral changes may include characteristic stereotypic movements. These movements, although without clear purpose, are not involuntary. Involuntary m...

  16. Lipoprotein lipase gene variants: Association with acute myocardial ...

    African Journals Online (AJOL)

    Lipoprotein lipase gene variants: Association with acute myocardial infarction and lipid profiles. ... Therefore, genes involved in lipid and lipoprotein metabolism pathways such as lipoprotein lipase (LPL), are proper candidates ... Article Metrics.

  17. Genetic variant as a marker for bladder cancer therapy

    Science.gov (United States)

    Patients who have inherited a specific common genetic variant develop bladder cancer tumors that strongly express a protein known as prostate stem cell antigen (PSCA), which is also expressed in many pancreatic and prostate tumors, according to research a

  18. Influenza A (H3N2) Variant Virus

    Science.gov (United States)

    ... Error processing SSI file Influenza A (H3N2) Variant Virus Language: English Español Recommend on Facebook Tweet Share Compartir Influenza viruses that normally circulate in pigs are called “ ...

  19. Variant Timekeeping Patterns and Their Effects in Jazz Drumming

    National Research Council Canada - National Science Library

    Butterfield, Matthew W

    2010-01-01

    ...." This essay shows how one modern jazz drummer employs variants of common timekeeping patterns in a more "liquid" way to generate motional energy through the strategic production of metric dissonance...

  20. Leapfrog variants of iterative methods for linear algebra equations

    Science.gov (United States)

    Saylor, Paul E.

    1988-01-01

    Two iterative methods are considered, Richardson's method and a general second order method. For both methods, a variant of the method is derived for which only even numbered iterates are computed. The variant is called a leapfrog method. Comparisons between the conventional form of the methods and the leapfrog form are made under the assumption that the number of unknowns is large. In the case of Richardson's method, it is possible to express the final iterate in terms of only the initial approximation, a variant of the iteration called the grand-leap method. In the case of the grand-leap variant, a set of parameters is required. An algorithm is presented to compute these parameters that is related to algorithms to compute the weights and abscissas for Gaussian quadrature. General algorithms to implement the leapfrog and grand-leap methods are presented. Algorithms for the important special case of the Chebyshev method are also given.