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Sanguinetti MC, Jiang C, Curran ME, Keating MT. A mechanistic link between an inherited and an acquired cardiac arrhythmia: HERG encodes the IKr potassium channel. Cell 1995; 81:299-307. [PMID: 7736582 DOI: 10.1016/0092-8674(95)90340-2] [Citation(s) in RCA: 1830] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mutations in HERG cause an inherited cardiac arrhythmia, long QT syndrome (LQT). To define the function of HERG, we expressed the protein in Xenopus oocytes. The biophysical properties of expressed HERG are nearly identical to the rapidly activating delayed rectifier K+ current (IKr) in cardiac myocytes. HERG current is K+ selective, declines with depolarizations above 0 mV, is activated by extracellular K+, and is blocked by lanthanum. Interestingly, HERG current is not blocked by drugs that specifically block IKr in cardiac myocytes. These data indicate that HERG proteins form IKr channels, but that an additional subunit may be required for drug sensitivity. Since block of IKr is a known mechanism for drug-induced cardiac arrhythmias, the finding that HERG encodes IKr channels provides a mechanistic link between certain forms of inherited and acquired LQT.
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Curran ME, Splawski I, Timothy KW, Vincent GM, Green ED, Keating MT. A molecular basis for cardiac arrhythmia: HERG mutations cause long QT syndrome. Cell 1995; 80:795-803. [PMID: 7889573 DOI: 10.1016/0092-8674(95)90358-5] [Citation(s) in RCA: 1605] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To identify genes involved in cardiac arrhythmia, we investigated patients with long QT syndrome (LQT), an inherited disorder causing sudden death from a ventricular tachyarrythmia, torsade de pointes. We previously mapped LQT loci on chromosomes 11 (LQT1), 7 (LQT2), and 3 (LQT3). Here, linkage and physical mapping place LQT2 and a putative potassium channel gene, HERG, on chromosome 7q35-36. Single strand conformation polymorphism and DNA sequence analyses reveal HERG mutations in six LQT families, including two intragenic deletions, one splice-donor mutation, and three missense mutations. In one kindred, the mutation arose de novo. Northern blot analyses show that HERG is strongly expressed in the heart. These data indicate that HERG is LQT2 and suggest a likely cellular mechanism for torsade de pointes.
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3
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Sanguinetti MC, Curran ME, Zou A, Shen J, Spector PS, Atkinson DL, Keating MT. Coassembly of K(V)LQT1 and minK (IsK) proteins to form cardiac I(Ks) potassium channel. Nature 1996; 384:80-3. [PMID: 8900283 DOI: 10.1038/384080a0] [Citation(s) in RCA: 1295] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The slowly activating delayed-rectifier K+ current, I(Ks), modulates the repolarization of cardiac action potentials. The molecular structure of the I(Ks) channel is not known, but physiological data indicate that one component of the I(Ks), channel is minK, a 130-amino-acid protein with a single putative transmembrane domain. The size and structure of this protein is such that it is unlikely that minK alone forms functional channels. We have previously used positional cloning techniques to define a new putative K+-channel gene, KVLQT1. Mutations in this gene cause long-QT syndrome, an inherited disorder that increases the risk of sudden death from cardiac arrhythmias. Here we show that KVLQT1 encodes a K+ channel with biophysical properties unlike other known cardiac currents. We considered that K(V)LQT1 might coassemble with another subunit to form functional channels in cardiac myocytes. Coexpression of K(V)LQT1 with minK induced a current that was almost identical to cardiac I(Ks). Therefore, K(V)LQT1 is the subunit that coassembles with minK to form I(Ks) channels and I(Ks) dysfunction is a cause of cardiac arrhythmia.
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Wang Q, Curran ME, Splawski I, Burn TC, Millholland JM, VanRaay TJ, Shen J, Timothy KW, Vincent GM, de Jager T, Schwartz PJ, Toubin JA, Moss AJ, Atkinson DL, Landes GM, Connors TD, Keating MT. Positional cloning of a novel potassium channel gene: KVLQT1 mutations cause cardiac arrhythmias. Nat Genet 1996; 12:17-23. [PMID: 8528244 DOI: 10.1038/ng0196-17] [Citation(s) in RCA: 1199] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Genetic factors contribute to the risk of sudden death from cardiac arrhythmias. Here, positional cloning methods establish KVLQT1 as the chromosome 11-linked LQT1 gene responsible for the most common inherited cardiac arrhythmia. KVLQT1 is strongly expressed in the heart and encodes a protein with structural features of a voltage-gated potassium channel. KVLQT1 mutations are present in affected members of 16 arrhythmia families, including one intragenic deletion and ten different missense mutations. These data define KVLQT1 as a novel cardiac potassium channel gene and show that mutations in this gene cause susceptibility to ventricular tachyarrhythmias and sudden death.
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Comparative Study |
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Spector PS, Curran ME, Zou A, Keating MT, Sanguinetti MC. Fast inactivation causes rectification of the IKr channel. J Gen Physiol 1996; 107:611-9. [PMID: 8740374 PMCID: PMC2217012 DOI: 10.1085/jgp.107.5.611] [Citation(s) in RCA: 321] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The mechanism of rectification of HERG, the human cardiac delayed rectifier K+ channel, was studied after heterologous expression in Xenopus oocytes. Currents were measured using two-microelectrode and macropatch voltage clamp techniques. The fully activated current-voltage (I-V) relationship for HERG inwardly rectified. Rectification was not altered by exposing the cytoplasmic side of a macropatch to a divalent-free solution, indicating this property was not caused by voltage-dependent block of outward current by Mg2+ or other soluble cytosolic molecules. The instantaneous I-V relationship for HERG was linear after removal of fast inactivation by a brief hyperpolarization. The time constants for the onset of and recovery from inactivation were a bell-shaped function of membrane potential. The time constants of inactivation varied from 1.8 ms at +50 mV to 16 ms at -20 mV; recovery from inactivation varied from 4.7 ms at -120 mV to 15 ms at -50 mV. Truncation of the NH2-terminal region of HERG shifted the voltage dependence of activation and inactivation by +20 to +30 mV. In addition, the rate of deactivation of the truncated channel was much faster than wild-type HERG. The mechanism of HERG rectification is voltage-gated fast inactivation. Inactivation of channels proceeds at a much faster rate than activation, such that no outward current is observed upon depolarization to very high membrane potentials. Fast inactivation of HERG and the resulting rectification are partly responsible for the prolonged plateau phase typical of ventricular action potentials.
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Sanguinetti MC, Curran ME, Spector PS, Keating MT. Spectrum of HERG K+-channel dysfunction in an inherited cardiac arrhythmia. Proc Natl Acad Sci U S A 1996; 93:2208-12. [PMID: 8700910 PMCID: PMC39936 DOI: 10.1073/pnas.93.5.2208] [Citation(s) in RCA: 309] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Long QT syndrome (LQT) is an autosomal dominant disorder that can cause sudden death from cardiac arrhythmias. We recently discovered that mutations in HERG, a K+-channel gene, cause chromosome 7-linked LQT. Heterologous expression of HERG in Xenopus oocytes revealed that HERG current was similar to a well-characterized cardiac delayed rectifier K+ current, IKr, and led to the hypothesis that mutations in HERG reduced IKr, causing prolonged myocellular action potentials. To define the mechanism of LQT, we injected oocytes with mutant HERG complementary RNAs, either singly or in combination with wild-type complementary RNA. Some mutations caused loss of function, whereas others caused dominant negative suppression of HERG function. These mutations are predicted to cause a spectrum of diminished IKr and delayed ventricular repolarization, consistent with the prolonged QT interval observed in individuals with LQT.
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Weese-Mayer DE, Berry-Kravis EM, Zhou L, Maher BS, Silvestri JM, Curran ME, Marazita ML. Idiopathic congenital central hypoventilation syndrome: Analysis of genes pertinent to early autonomic nervous system embryologic development and identification of mutations in PHOX2b. ACTA ACUST UNITED AC 2003; 123A:267-78. [PMID: 14608649 DOI: 10.1002/ajmg.a.20527] [Citation(s) in RCA: 261] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Idiopathic congenital central hypoventilation syndrome (CCHS) has been linked to autonomic nervous system dysregulation and/or dysfunction (ANSD) since it was first described in 1970. A genetic basis of CCHS has been proposed because of the reports of four families with two affected children, because of mother-child transmission, and because of a recent report of a polyalanine expansion mutation in PHOX2b in a subset of CCHS subjects. We, therefore, studied genes pertinent to early embryologic development of the ANS including mammalian achaete-scute homolog-1 (MASH1), bone morphogenic protein-2 (BMP2), engrailed-1 (EN1), TLX3, endothelin converting enzyme-1 (ECE1), endothelin-1 (EDN1), PHOX2a, and PHOX2b in 67 probands with CCHS, and gender- and ethnicity-matched controls. No disease-defining mutations were identified in MASH1, BMP2, EN1, TLX3, ECE1, EDN1, or PHOX2a. The 65/67 CCHS probands (97%) were found to be heterozygous for the exon 3 polyalanine expansion mutation identified previously in PHOX2b. Further, there was an association between repeat mutation length and severity of the CCHS/ANSD phenotype. Of the two probands who did not carry the expansion mutation, one had a nonsense mutation in exon 3 which truncated the protein and the other had no mutation in PHOX2b but had a previously reported EDN3 frameshift point mutation. The polyalanine expansion mutation was not found in any of 67 matched controls. Of 54 available families (including 97 unaffected parents), whose child carried the PHOX2b mutation, 4 parents demonstrated mosaicism for an expansion mutation identical to that seen in the CCHS cases, suggesting that not all mutations in affected probands with unaffected parents are de novo. We also studied four women with CCHS who were heterozygous for the PHOX2b mutation, each with one child. Three of the four children were also affected and had the same mutation, demonstrating autosomal dominant inheritance of the mutation. Assay of the PHOX2b polyalanine repeat mutation represents a highly sensitive and specific technique for confirming the diagnosis of CCHS. Identification of the CCHS mutation will lead to clarification of the phenotype, allow for prenatal diagnosis for parents of CCHS probands and adults with CCHS in future pregnancies, and potentially direct intervention strategies for the treatment of CCHS.
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Curran ME, Atkinson DL, Ewart AK, Morris CA, Leppert MF, Keating MT. The elastin gene is disrupted by a translocation associated with supravalvular aortic stenosis. Cell 1993; 73:159-68. [PMID: 8096434 DOI: 10.1016/0092-8674(93)90168-p] [Citation(s) in RCA: 258] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To identify genes involved in vascular disease, we investigated patients with supravalvular aortic stenosis (SVAS), an inherited vascular disorder that causes hemodynamically significant narrowing of large elastic arteries. Pulsed-field gel and Southern analyses showed that a translocation near the elastin gene cosegregated with SVAS in one family. DNA sequence analyses demonstrated that the translocation disrupted the elastin gene and localized the breakpoint to exon 28. Taken together with our previous study linking SVAS to the elastin gene in two additional families and existing knowledge of vascular biology, these data suggest that mutations in the elastin gene can cause SVAS.
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Hampe J, Schreiber S, Shaw SH, Lau KF, Bridger S, Macpherson AJ, Cardon LR, Sakul H, Harris TJ, Buckler A, Hall J, Stokkers P, van Deventer SJ, Nürnberg P, Mirza MM, Lee JC, Lennard-Jones JE, Mathew CG, Curran ME. A genomewide analysis provides evidence for novel linkages in inflammatory bowel disease in a large European cohort. Am J Hum Genet 1999; 64:808-16. [PMID: 10053016 PMCID: PMC1377799 DOI: 10.1086/302294] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Inflammatory bowel disease (IBD) is characterized by a chronic relapsing intestinal inflammation, typically starting in early adulthood. IBD is subdivided into two subtypes, on the basis of clinical and histologic features: Crohn disease and ulcerative colitis (UC). Previous genomewide searches identified regions harboring susceptibility loci on chromosomes 1, 3, 4, 7, 12, and 16. To expand our understanding of the genetic risk profile, we performed a 9-cM genomewide search for susceptibility loci in 268 families containing 353 affected sibling pairs. Previous linkages on chromosomes 12 and 16 were replicated, and the chromosome 4 linkage was extended in this sample. New suggestive evidence for autosomal linkages was observed on chromosomes 1, 6, 10, and 22, with LOD scores of 2.08, 2.07, 2.30, and 1.52, respectively. A maximum LOD score of 1.76 was observed on the X chromosome, for UC, which is consistent with the clinical association of IBD with Ullrich-Turner syndrome. The linkage finding on chromosome 6p is of interest, given the possible contribution of human leukocyte antigen and tumor necrosis-factor genes in IBD. This genomewide linkage scan, done with a large family cohort, has confirmed three previous IBD linkages and has provided evidence for five additional regions that may harbor IBD predisposition genes.
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Ackerman MJ, Tester DJ, Jones GS, Will ML, Burrow CR, Curran ME. Ethnic differences in cardiac potassium channel variants: implications for genetic susceptibility to sudden cardiac death and genetic testing for congenital long QT syndrome. Mayo Clin Proc 2003; 78:1479-87. [PMID: 14661677 DOI: 10.4065/78.12.1479] [Citation(s) in RCA: 227] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To determine the spectrum, frequency, and ethnic-specificity of channel variants in the potassium channel genes implicated in congenital long QT syndrome (LQTS) among healthy subjects. SUBJECTS AND METHODS Genomic DNA from 744 apparently healthy individuals-305 black, 187 white, 134 Asian, and 118 Hispanic--was subject to a comprehensive mutational analysis of the 4 LQTS-causing potassium channel genes: KCNQ1 (LQT1), KCNH2 (LQT2), KCNE1 (LQT5), and KCNE2 (LQT6). RESULTS Overall, 49 distinct amino acid-altering variants (36 novel) were identified: KCNQ1 (n = 16), KCNH2 (n = 25),KCNE1 (n = 5), and KCNE2 (n = 3). More than half of these variants (26/49) were found exclusively in black subjects. The known K897T-HERG and the G38S-min K common polymorphisms were identified in all 4 ethnic groups. Excluding these 2 common polymorphisms, 25% of black subjects had at least 1 nonsynonymous potassium channel variant compared with 14% of white subjects (P < .01). CONCLUSIONS To our knowledge, this study represents the first comprehensive determination of the frequency and spectrum of cardiac channel variants found among healthy subjects from 4 major ethnic groups. Defining the population burden of genetic variants in these critical cardiac ion channels is crucial for proper interpretation of genetic test results of individuals at risk for LQTS. This compendium provides a resource for epidemiological and functional investigation of variant effects on the repolarization properties of cardiac tissues, including susceptibility to lethal cardiac arrhythmias.
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Ackerman MJ, Splawski I, Makielski JC, Tester DJ, Will ML, Timothy KW, Keating MT, Jones G, Chadha M, Burrow CR, Stephens JC, Xu C, Judson R, Curran ME. Spectrum and prevalence of cardiac sodium channel variants among black, white, Asian, and Hispanic individuals: implications for arrhythmogenic susceptibility and Brugada/long QT syndrome genetic testing. Heart Rhythm 2005; 1:600-7. [PMID: 15851227 DOI: 10.1016/j.hrthm.2004.07.013] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 07/18/2004] [Indexed: 12/19/2022]
Abstract
OBJECTIVES The purpose of this study was to determine the prevalence and spectrum of nonsynonymous polymorphisms (amino acid variants) in the cardiac sodium channel among healthy subjects. BACKGROUND Pathogenic mutations in the cardiac sodium channel gene, SCN5A, cause approximately 15 to 20% of Brugada syndrome (BrS1), 5 to 10% of long QT syndrome (LQT3), and 2 to 5% of sudden infant death syndrome. METHODS Using single-stranded conformation polymorphism, denaturing high-performance liquid chromatography, and/or direct DNA sequencing, mutational analysis of the protein-encoding exons of SCN5A was performed on 829 unrelated, anonymous healthy subjects: 319 black, 295 white, 112 Asian, and 103 Hispanic. RESULTS In addition to the four known common polymorphisms (R34C, H558R, S1103Y, and R1193Q), four relatively ethnic-specific polymorphisms were identified: R481W, S524Y, P1090L, and V1951L. Overall, 39 distinct missense variants (28 novel) were elucidated. Nineteen variants (49%) were found only in the black cohort. Only seven variants (18%) localized to transmembrane-spanning domains. Four variants (F1293S, R1512W, and V1951L cited previously as BrS1-causing mutations and S1787N previously published as a possible LQT3-causing mutation) were identified in this healthy cohort. CONCLUSIONS This study provides the first comprehensive determination of the prevalence and spectrum of cardiac sodium channel variants in healthy subjects from four distinct ethnic groups. This compendium of SCN5A variants is critical for proper interpretation of SCN5A genetic testing and provides an essential hit list of targets for future functional studies to determine whether or not any of these variants mediate genetic susceptibility for arrhythmias in the setting of either drugs or disease.
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Research Support, U.S. Gov't, P.H.S. |
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Spector PS, Curran ME, Keating MT, Sanguinetti MC. Class III antiarrhythmic drugs block HERG, a human cardiac delayed rectifier K+ channel. Open-channel block by methanesulfonanilides. Circ Res 1996; 78:499-503. [PMID: 8593709 DOI: 10.1161/01.res.78.3.499] [Citation(s) in RCA: 216] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We recently reported that mutations in HERG, a potassium channel gene, cause long QT syndrome. Heterologous expression of HERG in Xenopus oocytes revealed that this channel had biophysical properties nearly identical to a cardiac delayed rectifier K+ current I(Kr), but had dissimilar pharmacological properties. Class III antiarrhythmic drugs such as E-4031 and MK-499 are potent and specific blockers of I (Kr) in cardiac myocytes. Our initial studies indicated that these compounds did not block HERG at a concentration of 1 micromol/L. In the present study, we used standard two-microelectrode voltage-clamp techniques to further characterize the effects of these drugs on HERG channels expressed in oocytes. Consistent with initial findings, 1 micromol/L MK-499 and E-4031 had not effect on HERG when oocytes were voltage clamped at a negative potential and not pulsed during equilibration with the drug. However, MK-499 did block HERG current if oocytes were repetitively pulsed, or clamped at a voltage positive to the threshold potential for channel activation. This finding is in contrast to previous studies that showed significant block of I(Kr) in isolated myocytes by similar drugs, even in the absence of pulsing. This apparent discrepancy may be due to differences in channel characteristics (HERG versus guinea pig and mouse I (Kr)), tissue (oocytes versus myocytes), or specific drugs. Under steady state conditions, block of HERG by MK-499 was half maximal at 123 +/- 12 nmol/L at a test potential of -20 mV. MK-499 (150 nmol/L) did not affect the voltage dependence of activation and rectification nor the kinetics of activation and deactivation of HERG. These data indicate that MK-499 preferentially blocks open HERG channels and further support the conclusion that HERG subunits form I(Kr) channels in cardiac myocytes.
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Zimmerberg J, Curran M, Cohen FS, Brodwick M. Simultaneous electrical and optical measurements show that membrane fusion precedes secretory granule swelling during exocytosis of beige mouse mast cells. Proc Natl Acad Sci U S A 1987; 84:1585-9. [PMID: 3470745 PMCID: PMC304480 DOI: 10.1073/pnas.84.6.1585] [Citation(s) in RCA: 191] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mast cells show dramatic morphological changes when undergoing exocytosis. We have investigated whether the first of those morphological changes, swelling of the secretory granule, precedes--and therefore possibly initiates--secretion or whether it occurs after fusion of the granule and plasma membranes. We used cell membrane capacitance to detect the moment when granule and plasma membrane become continuous. We measured large capacitance increases, often preceded by transients in capacitance. The rise-times of the capacitance increases were half-maximal at 2-59 msec. We observed cells with high-resolution video microscopy while these measurements were done. The capacitance increase always preceded the granular swelling that leads to exocytosis. To rule out the possibility that fusion was induced by a mechanical stress imparted by the internal pressure of a taut granule, we performed control experiments using cells in which vesicles were shrunken with hyperosmotic solutions. With these flaccid granules, again, the capacitance rise always preceded the swelling of the granules. We conclude that swelling cannot be the driving force for membrane fusion in this system.
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191 |
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Hampe J, Shaw SH, Saiz R, Leysens N, Lantermann A, Mascheretti S, Lynch NJ, MacPherson AJS, Bridger S, van Deventer S, Stokkers P, Morin P, Mirza MM, Forbes A, Lennard-Jones JE, Mathew CG, Curran ME, Schreiber S. Linkage of inflammatory bowel disease to human chromosome 6p. Am J Hum Genet 1999; 65:1647-55. [PMID: 10577918 PMCID: PMC1288375 DOI: 10.1086/302677] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/1999] [Accepted: 09/08/1999] [Indexed: 11/03/2022] Open
Abstract
Inflammatory bowel disease (IBD) is characterized by a chronic relapsing intestinal inflammation. IBD is subdivided into Crohn disease and ulcerative colitis phenotypes. Given the immunologic dysregulation in IBD, the human-leukocyte-antigen region on chromosome 6p is of significant interest. Previous association and linkage analysis has provided conflicting evidence as to the existence of an IBD-susceptibility locus in this region. Here we report on a two-stage linkage and association analysis of both a basic population of 353 affected sibling pairs (ASPs) and an extension of this population to 428 white ASPs of northern European extraction. Twenty-eight microsatellite markers on chromosome 6 were genotyped. A peak multipoint LOD score of 4.2 was observed, at D6S461, for the IBD phenotype. A transmission/disequilibrium test (TDT) result of P=.006 was detected for D6S426 in the basic population and was confirmed in the extended cohort (P=.004; 97 vs. 56 transmissions). The subphenotypes of Crohn disease, ulcerative colitis, and mixed IBD contributed equally to this linkage, suggesting a general role for the chromosome 6 locus in IBD. Analysis of five single-nucleotide polymorphisms in the TNFA and LTA genes did not reveal evidence for association of these important candidate genes with IBD. In summary, we provide firm linkage evidence for an IBD-susceptibility locus on chromosome 6p and demonstrate that TNFA and LTA are unlikely to be susceptibility loci for IBD.
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research-article |
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172 |
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Zimmerberg J, Blumenthal R, Sarkar DP, Curran M, Morris SJ. Restricted movement of lipid and aqueous dyes through pores formed by influenza hemagglutinin during cell fusion. J Cell Biol 1994; 127:1885-94. [PMID: 7806567 PMCID: PMC2120276 DOI: 10.1083/jcb.127.6.1885] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The fusion of cells by influenza hemagglutinin (HA) is the best characterized example of protein-mediated membrane fusion. In simultaneous measurements of pairs of assays for fusion, we determined the order of detectable events during fusion. Fusion pore formation in HA-triggered cell-cell fusion was first detected by changes in cell membrane capacitance, next by a flux of fluorescent lipid, and finally by flux of aqueous fluorescent dye. Fusion pore conductance increased by small steps. A retardation of lipid and aqueous dyes occurred during fusion pore fluctuations. The flux of aqueous dye depended on the size of the molecule. The lack of movement of aqueous dyes while total fusion pore conductance increased suggests that initial HA-triggered fusion events are characterized by the opening of multiple small pores: the formation of a "sieve".
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research-article |
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138 |
16
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Granger DA, Schwartz EB, Booth A, Curran M, Zakaria D. Assessing dehydroepiandrosterone in saliva: a simple radioimmunoassay for use in studies of children, adolescents and adults. Psychoneuroendocrinology 1999; 24:567-79. [PMID: 10378242 DOI: 10.1016/s0306-4530(99)00013-x] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
While salivary assays for some hormones are widely used, the availability of assays for salivary DHEA is limited. By adapting a commercially available radioimmunoassay serum kit, we developed a reliable, efficient and sensitive measure of DHEA in saliva that does not require separation or extraction. The minimum detection limit was 4.0 pg/ml. Intra-assay coefficients of variation (CV%) were on average 4.05, and inter-assay CVs averaged 9.70. Method accuracy, determined by spike recovery, and linearity, determined by serial dilution, averaged 99.55 and 92.03%. Levels in matched serum and saliva samples showed strong linear relationships for adult males and females. Specific guidelines are developed for sample collection, storage, and preparation procedures. Reference ranges for salivary DHEA levels are provided for 64 children ages 8-11, 96 adolescents ages 12-17 and 48 adults ages 30-45. Salivary DHEA levels are shown to reflect developmental, gender and diurnal differences.
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17
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Curran ME, Lau KF, Hampe J, Schreiber S, Bridger S, Macpherson AJ, Cardon LR, Sakul H, Harris TJ, Stokkers P, Van Deventer SJ, Mirza M, Raedler A, Kruis W, Meckler U, Theuer D, Herrmann T, Gionchetti P, Lee J, Mathew C, Lennard-Jones J. Genetic analysis of inflammatory bowel disease in a large European cohort supports linkage to chromosomes 12 and 16. Gastroenterology 1998; 115:1066-71. [PMID: 9797359 DOI: 10.1016/s0016-5085(98)70075-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Inflammatory bowel disease (IBD) is a complex disorder of unknown etiology. Epidemiological investigations suggest a genetic basis for IBD. Recent genetic studies have identified several IBD linkages. The significance of these linkages will be determined by studies in large patient collections. The aim of this study was to replicate IBD linkages on chromosomes 12 and 16 in a large European cohort. METHODS Three hundred fifty-nine affected sibling pairs from 274 kindreds were genotyped using microsatellite markers spanning chromosomes 12 and 16. Affection status of the sibling pairs was defined as Crohn's disease (CD) or ulcerative colitis (UC). RESULTS Nonparametric statistical analyses showed linkage for both chromosomes. Two-point results for chromosome 12 peaked at D12S303 (logarithm of odds [LOD], 2.15; P = 0.003) for CD and at D12S75 (LOD, 0.92; P = 0.03) for UC. Multipoint analyses produced a peak LOD of 1.8 for CD. Chromosome 16 showed linkage for CD at marker D16S415 (LOD, 1.52; P = 0.007). Multipoint support peaked above markers D16S409 and D16S411 (LOD, 1.7). CONCLUSIONS These data are consistent with linkage of IBD to chromosomes 12 and 16. The replication of genetic risk loci in a large independent family collection indicates important and common susceptibility genes in these regions and will facilitate identification of genes involved in IBD.
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Weese-Mayer DE, Berry-Kravis EM, Maher BS, Silvestri JM, Curran ME, Marazita ML. Sudden infant death syndrome: association with a promoter polymorphism of the serotonin transporter gene. Am J Med Genet A 2003; 117A:268-74. [PMID: 12599191 DOI: 10.1002/ajmg.a.20005] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Serotonergic receptor binding in the arcuate nucleus, n. raphé obscurus, and other medullary regions is decreased in sudden infant death syndrome (SIDS) cases. Further, a variable tandem repeat sequence polymorphism in the promoter region of the serotonin transporter protein (5-HTT) gene has recently been associated with risk of SIDS in a Japanese cohort. This polymorphism differentially regulates 5-HTT expression, with the long allele (L), the SIDS-associated allele, being a more effective promoter than the short allele (S). We therefore investigated the 5-HTT promoter polymorphism in a cohort of 87 SIDS cases (43 African American and 44 Caucasian) and gender/ethnicity-matched controls. Significant positive associations were found between SIDS and the 5-HTT genotype distribution (P = 0.022), specifically with the L/L genotype (P = 0.048), and between SIDS and the 5-HTT L allele (P = 0.005). There was also a significant negative association between SIDS and the S/S genotype (P = 0.011). The comparisons were repeated in the African American and Caucasian subgroups. The data patterns were consistent in the subgroups, i.e., the L/L genotype and L allele were increased in the cases, but not all subgroup comparisons were statistically significant. These results indicate a relationship between SIDS and the L allele of the 5-HTT gene in African Americans and Caucasians, and if confirmed, will provide an important tool for identifying at-risk individuals and estimating the risk of recurrence.
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Koller DL, Rodriguez LA, Christian JC, Slemenda CW, Econs MJ, Hui SL, Morin P, Conneally PM, Joslyn G, Curran ME, Peacock M, Johnston CC, Foroud T. Linkage of a QTL contributing to normal variation in bone mineral density to chromosome 11q12-13. J Bone Miner Res 1998; 13:1903-8. [PMID: 9844108 DOI: 10.1359/jbmr.1998.13.12.1903] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Osteoporosis is a leading public health problem that is responsible for substantial morbidity and mortality. A major determinant of the risk for osteoporosis in later life is bone mineral density (BMD) attained during early adulthood. BMD is a complex trait that presumably is influenced by multiple genes. Recent linkage of three Mendelian BMD-related phenotypes, autosomal dominant high bone mass, autosomal recessive osteoporosis-pseudoglioma, and autosomal recessive osteopetrosis to chromosome 11q12-13 led us to evaluate this region to determine if the underlying gene(s) could also contribute to variation in BMD in the normal population. We performed a linkage study in a sample of 835 premenopausal Caucasian and African-American sisters to identify genes underlying BMD variation. A maximum multipoint LOD score of 3.50 with femoral neck BMD was obtained near the marker D11S987, in the same chromosomal region as the three Mendelian traits mentioned above. Our results suggest that the gene(s) underlying these Mendelian phenotypes also play a role in determining peak BMD in the normal population and are the first using linkage methods to establish a chromosomal location for a gene important in determining peak BMD. These findings support the hypothesis that a gene responsible for one or more of the rare Mendelian BMD traits linked to chromosome 11q12-13 has an important role in osteoporosis in the general population.
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Suárez-Fariñas M, Tokuyama M, Wei G, Huang R, Livanos A, Jha D, Levescot A, Irizar H, Kosoy R, Cording S, Wang W, Losic B, Ungaro RC, Di’Narzo A, Martinez-Delgado G, Suprun M, Corley MJ, Stojmirovic A, Houten SM, Peters L, Curran M, Brodmerkel C, Perrigoue J, Friedman JR, Hao K, Schadt EE, Zhu J, Ko HM, Cho J, Dubinsky MC, Sands BE, Ndhlovu L, Cerf-Bensusan N, Kasarskis A, Colombel JF, Harpaz N, Argmann C, Mehandru S. Intestinal Inflammation Modulates the Expression of ACE2 and TMPRSS2 and Potentially Overlaps With the Pathogenesis of SARS-CoV-2-related Disease. Gastroenterology 2021; 160:287-301.e20. [PMID: 32980345 PMCID: PMC7516468 DOI: 10.1053/j.gastro.2020.09.029] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/14/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND AIMS The presence of gastrointestinal symptoms and high levels of viral RNA in the stool suggest active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication within enterocytes. METHODS Here, in multiple, large cohorts of patients with inflammatory bowel disease (IBD), we have studied the intersections between Coronavirus Disease 2019 (COVID-19), intestinal inflammation, and IBD treatment. RESULTS A striking expression of ACE2 on the small bowel enterocyte brush border supports intestinal infectivity by SARS-CoV-2. Commonly used IBD medications, both biologic and nonbiologic, do not significantly impact ACE2 and TMPRSS2 receptor expression in the uninflamed intestines. In addition, we have defined molecular responses to COVID-19 infection that are also enriched in IBD, pointing to shared molecular networks between COVID-19 and IBD. CONCLUSIONS These data generate a novel appreciation of the confluence of COVID-19- and IBD-associated inflammation and provide mechanistic insights supporting further investigation of specific IBD drugs in the treatment of COVID-19. Preprint doi: https://doi.org/10.1101/2020.05.21.109124.
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Oligino L, Lung FD, Sastry L, Bigelow J, Cao T, Curran M, Burke TR, Wang S, Krag D, Roller PP, King CR. Nonphosphorylated peptide ligands for the Grb2 Src homology 2 domain. J Biol Chem 1997; 272:29046-52. [PMID: 9360978 DOI: 10.1074/jbc.272.46.29046] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Critical intracellular signals in normal and malignant cells are transmitted by the adaptor protein Grb2 by means of its Src homology 2 (SH2) domain, which binds to phosphotyrosyl (pTyr) residues generated by the activation of tyrosine kinases. To understand this important control point and to design inhibitors, previous investigations have focused on the molecular mechanisms by which the Grb2 SH2 domain selectively binds pTyr containing peptides. In the current study, we demonstrate that the Grb2 SH2 domain can also bind in a pTyr independent manner. Using phage display, an 11-amino acid cyclic peptide, G1, has been identified that binds to the Grb2 SH2 domain but not the src SH2 domain. Synthetic G1 peptide blocks Grb2 SH2 domain association (IC50 10-25 microM) with a 9-amino acid pTyr-containing peptide derived from the SHC protein (pTyr317). These data and amino acid substitution analysis indicate that G1 interacts in the phosphopeptide binding site. G1 peptide requires a YXN sequence similar to that found in natural pTyr-containing ligands, and phosphorylation of the tyrosine increases G1 inhibitory activity. G1 also requires an internal disulfide bond to maintain the active binding conformation. Since the G1 peptide does not contain pTyr, it defines a new type of SH2 domain binding motif that may advance the design of Grb2 antagonists.
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Weese-Mayer DE, Berry-Kravis EM, Zhou L, Maher BS, Curran ME, Silvestri JM, Marazita ML. Sudden infant death syndrome: case-control frequency differences at genes pertinent to early autonomic nervous system embryologic development. Pediatr Res 2004; 56:391-5. [PMID: 15240857 DOI: 10.1203/01.pdr.0000136285.91048.4a] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have previously identified polymorphisms in the serotonin transporter gene promoter region and in intron 2 that were more common among sudden infant death syndrome (SIDS) cases compared with control subjects. To elucidate further the genetic profile that might increase an infant's vulnerability to SIDS, we focused on the recognized relationship between autonomic nervous system (ANS) dysregulation and SIDS. We therefore studied genes pertinent to early embryologic development of the ANS, including MASH1, BMP2, PHOX2a, PHOX2b, RET, ECE1, EDN1, TLX3, and EN1 in 92 probands with SIDS and 92 gender- and ethnicity-matched control subjects. Eleven protein-changing rare mutations were identified in 14 of 92 SIDS cases among the PHOX2a, RET, ECE1, TLX3, and EN1 genes. Only 1 of these mutations (TLX3) was identified in 2 of 92 control subjects. Black infants accounted for 10 of these mutations in SIDS cases and 2 control subjects. Four protein-changing common polymorphisms were identified in BMP2, RET, ECE1, and EDN1, but the allele frequency did not differ between SIDS cases and control subjects. However, among SIDS cases, the allele frequency for the BMP2 common polymorphism demonstrated ethnic differences; among control subjects, the allele frequency for the BMP2 and the ECE1 common polymorphisms also demonstrated ethnic differences. These data represent further refinement of the genetic profile that might place an infant at risk for SIDS.
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Yamazaki K, Beauchamp GK, Curran M, Bard J, Boyse EA. Parent-progeny recognition as a function of MHC odortype identity. Proc Natl Acad Sci U S A 2000; 97:10500-2. [PMID: 10973487 PMCID: PMC27053 DOI: 10.1073/pnas.180320997] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2000] [Indexed: 11/18/2022] Open
Abstract
The several linked polymorphic genes of the MHC, which has been proposed as a prime determinant of sensed genetic individuality within species, is known to operate in mice by olfactory recognition in aspects of reproductive behavior that concern mate selection, thereby favoring outbreeding and heterozygosity, and also concern the maintenance of pregnancy. A single base-change can alter an individual MHC odortype, and the potential range of combinatorial MHC-determined odortypes is clearly vast. Following our findings that newborn mice already express their MHC odortype (which is detectable at 9 days of gestational age), we sought to determine whether MHC is involved in behavioral aspects of early development, such as rearing. In the studies presented herein, we report the ability and proclivity of mothers to recognize and preferentially retrieve syngeneic (genetically identical) pups from other pups differing only for MHC. Reciprocally, we report the ability of pups to recognize their familial environment, regardless of whether they had been nursed by their biological mothers or by foster mothers. Early learning experiences of the MHC environment are apparently a key element in survival, assuring maternal protection and promoting outbreeding.
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Li Q, Lee CH, Peters LA, Mastropaolo LA, Thoeni C, Elkadri A, Schwerd T, Zhu J, Zhang B, Zhao Y, Hao K, Dinarzo A, Hoffman G, Kidd BA, Murchie R, Adham ZA, Guo C, Kotlarz D, Cutz E, Walters TD, Shouval DS, Curran M, Dobrin R, Brodmerkel C, Snapper SB, Klein C, Brumell JH, Hu M, Nanan R, Snanter-Nanan B, Wong M, Le Deist F, Haddad E, Roifman CM, Deslandres C, Griffiths AM, Gaskin KJ, Uhlig HH, Schadt EE, Muise AM. Variants in TRIM22 That Affect NOD2 Signaling Are Associated With Very-Early-Onset Inflammatory Bowel Disease. Gastroenterology 2016; 150:1196-1207. [PMID: 26836588 PMCID: PMC4842103 DOI: 10.1053/j.gastro.2016.01.031] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/22/2016] [Accepted: 01/22/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Severe forms of inflammatory bowel disease (IBD) that develop in very young children can be caused by variants in a single gene. We performed whole-exome sequence (WES) analysis to identify genetic factors that might cause granulomatous colitis and severe perianal disease, with recurrent bacterial and viral infections, in an infant of consanguineous parents. METHODS We performed targeted WES analysis of DNA collected from the patient and her parents. We validated our findings by a similar analysis of DNA from 150 patients with very-early-onset IBD not associated with known genetic factors analyzed in Toronto, Oxford, and Munich. We compared gene expression signatures in inflamed vs noninflamed intestinal and rectal tissues collected from patients with treatment-resistant Crohn's disease who participated in a trial of ustekinumab. We performed functional studies of identified variants in primary cells from patients and cell culture. RESULTS We identified a homozygous variant in the tripartite motif containing 22 gene (TRIM22) of the patient, as well as in 2 patients with a disease similar phenotype. Functional studies showed that the variant disrupted the ability of TRIM22 to regulate nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-κB. Computational studies demonstrated a correlation between the TRIM22-NOD2 network and signaling pathways and genetic factors associated very early onset and adult-onset IBD. TRIM22 is also associated with antiviral and mycobacterial effectors and markers of inflammation, such as fecal calprotectin, C-reactive protein, and Crohn's disease activity index scores. CONCLUSIONS In WES and targeted exome sequence analyses of an infant with severe IBD characterized by granulomatous colitis and severe perianal disease, we identified a homozygous variant of TRIM22 that affects the ability of its product to regulate NOD2. Combined computational and functional studies showed that the TRIM22-NOD2 network regulates antiviral and antibacterial signaling pathways that contribute to inflammation. Further study of this network could lead to new disease markers and therapeutic targets for patients with very early and adult-onset IBD.
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Breadmore MC, Palmer AS, Curran M, Macka M, Avdalovic N, Haddad PR. On-column ion-exchange preconcentration of inorganic anions in open tubular capillary electrochromatography with elution using transient-isotachophoretic gradients. 3. Implementation and method development. Anal Chem 2002; 74:2112-8. [PMID: 12033314 DOI: 10.1021/ac011217u] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A solid-phase extraction method based on an ion-exchange retention mechanism has been used for in-line preconcentration of inorganic anions prior to their separation by capillary electrophoresis (CE). A single capillary containing a preconcentration and a separation zone has been used in a commercial CE instrument without instrumental modification. Analyte anions were retained on a preconcentration zone comprising an adsorbed layer of cationic latex particles, while separation was achieved in a separation zone comprising fused silica modified by adsorption of a cationic polymer. Elution of the adsorbed analytes was achieved using an eluotropic gradient formed by a transient isotachophoretic boundary between a fluoride electrolyte and a naphthalenedisulfonate electrolyte. Optimization of the electrolyte concentrations, sample injection times, and back-flushing times allowed the successful separation of sub-ppb levels of inorganic anions using a 100-min injection at 2 bar pressure, introducing over 40 capillary volumes of sample. A method based on a 10-min injection allowed a 100-fold increase in sensitivity over conventional hydrodynamic injection for Br-, I-, NO3-, CrO4(2-), and MoO4(2-) with a total analysis time of 25 min. Detection limits were dependent on the injection time but were in the range 2.2-11.6 ppb for a 10-min injection time. This approach was used to determine NO3- in Antarctic ice cores where the analysis could be performed using a sample volume 100 times less than that used for ion chromatography.
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