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Wang SX, Streit A. Shared features in ear and kidney development - implications for oto-renal syndromes. Dis Model Mech 2024; 17:dmm050447. [PMID: 38353121 PMCID: PMC10886756 DOI: 10.1242/dmm.050447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms.
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Affiliation(s)
- Scarlet Xiaoyan Wang
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
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Ay E, Gurses E, Aslan F, Gulhan B, Alniacik A, Duzova A, Bajin MD, Sennaroglu L, Genc GA, Ozaltin F, Topaloglu R. Hearing Loss Related to Gene Mutations in Distal Renal Tubular Acidosis. Audiol Neurootol 2023; 28:350-359. [PMID: 37121229 DOI: 10.1159/000529486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 01/30/2023] [Indexed: 05/02/2023] Open
Abstract
INTRODUCTION Distal renal tubular acidosis (dRTA) is a disease that may develop either primarily or secondarily, resulting from urinary acidification defects in distal tubules. Hearing loss may accompany primary forms of dRTA. This study aims to determine the characteristics of hearing loss due to different gene mutations in patients with dRTA. METHODS Behavioral and electrophysiological audiological evaluations were performed after otolaryngology examination in 21 patients with clinically diagnosed dRTA. Radiological imaging of the inner ear (n = 9) was conducted and results of genetic analyses using next-generation sequencing method (n = 16) were included. RESULTS Twenty-one patients with dRTA from 20 unrelated families, aged between 8 months and 33 years (median = 12, interquartile range = 20), participated. All patients with ATP6V1B1 mutations (n = 9) had different degrees of hearing loss. There was one patient with hearing loss in patients with ATP6V0A4 mutations (n = 6). One patient with the WDR72 mutation had normal hearing. Large vestibular aqueduct syndrome (LVAS) was detected in 6 (67%) of 9 patients whose radiological evaluation results were available. CONCLUSIONS LVAS is common in patients with dRTA and may influence the type and severity of hearing loss in these patients. The possibility of both congenital and late-onset and progressive hearing loss should be considered in dRTA patients. A regular audiological follow-up is essential for the early detection of a possible late-onset or progressive hearing loss in these patients.
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Affiliation(s)
- Ezgi Ay
- Department of Audiology, Baskent University Faculty of Health Sciences, Ankara, Turkey
| | - Emre Gurses
- Department of Audiology, Hacettepe University Faculty of Health Sciences, Ankara, Turkey
| | - Filiz Aslan
- Department of Audiology, Hacettepe University Faculty of Health Sciences, Ankara, Turkey
| | - Bora Gulhan
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Asuman Alniacik
- Department of Audiology, Baskent University Faculty of Health Sciences, Ankara, Turkey
| | - Ali Duzova
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Munir Demir Bajin
- Department of Ear Nose and Throat, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Levent Sennaroglu
- Department of Ear Nose and Throat, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Gulsum Aydan Genc
- Department of Audiology, Hacettepe University Faculty of Health Sciences, Ankara, Turkey
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
- Nephrogenetics Laboratory, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Rezan Topaloglu
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Ankara, Turkey
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Fatima A, Mohamed A, Moustapha H, Karim O. Molecular Diagnosis of Primary Hyperoxaluria Type 1 and Distal Renal Tubular Acidosis in Moroccan Patients With Nephrolithiasis and/or Nephrocalcinosis. Cureus 2022; 14:e23616. [PMID: 35505724 PMCID: PMC9053370 DOI: 10.7759/cureus.23616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2022] [Indexed: 11/11/2022] Open
Abstract
Nephrolithiasis (NL) and urolithiasis (UL) are usual reasons for hospitalization and presentation in pediatric outpatient departments and their incidence continues to rise worldwide. In Morocco, a previous epidemiological study done in the Fez region between January 2003 and November 2013 reported a prevalence of 0.83% of childhood UL. In two studies, heritability accounted for almost half of all NL or nephrocalcinosis (NC) prevalence. Genetic factors must be considered in the etiological diagnosis of urinary lithiasis in Morocco since the frequency of consanguineous marriages is high. Hereditary tubular disorders, especially distal renal tubular acidosis (dRTA) and Dent disease, and metabolic disorders like idiopathic hypercalciuria and hyperoxaluria are the most common causes of medullary NC. Primary hyperoxaluria type 1 (PH1), which can generate an early onset of NC, and often chronic kidney disease (CKD) should always be considered and thoroughly diagnosed. The aim of this work was to establish a molecular diagnosis of PH1 and dRTA and, thus, to predict and explain the disease phenotype in a cohort of 44 Moroccan patients with NL and/or NC by analyzing the AGXT and ATP6V1B1 genes that cause NL and/or NC when mutated. Disease phenotype was molecularly explained and solved in six of 44 individuals with NL and/or NC (13.6%). In the pediatric subgroup of individuals, a causative mutation in 16.2% was identified, whereas in the adult cohort no pathogenic mutation was detected. In our patients, PH1 was objectified in 67% of cases followed by dRTA in 33% of cases. We suggest that prompt detection and prophylactic treatment of UL are necessary to limit the risk of everlasting renal damage and thus prevent or delay the progression to CKD.
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Chen J, He J, Luo J, Zhong S. Association of αENaC p. Ala663Thr Gene Polymorphism With Sudden Sensorineural Hearing Loss. Front Genet 2022; 12:659517. [PMID: 35024042 PMCID: PMC8744410 DOI: 10.3389/fgene.2021.659517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 12/08/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: The etiology of sudden sensorineural hearing loss (SSNHL) is still unknown. It has been demonstrated that normal endolymph metabolism is essential for inner ear function and that epithelial sodium channels (ENaC) may play an important role in the regulation of endolymphatic Na+. This study aimed to explore the potential association between αENaC p. Ala663Thr gene polymorphism and SSNHL. Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to examine the genotype and allele frequency of the αENaC p. Ala663Thr polymorphism in 20 cases of low-frequency SSNHL (LF-SSNHL), 19 cases of high-frequency SSNHL (HF-SSNHL), 31 cases of all frequency SSNHL (AF-SSNHL), 42 cases of profound deafness SSNHL (PD-SSNHL), and 115 normal controls. Results: The T663 allele was found to be significantly associated with an increased risk of LF-SSNHL (p = 0.046, OR = 2.16, 95% CI = 1.01-4.62). The TT genotype and T663 allele, on the other hand, conferred a protective effect for PD-SSNHL (AA vs. TT: p = 0.012, OR = 0.25, 95% CI = 0.08-0.74; A vs. T: p = 0.001, OR = 0.36, 95% CI = 0.21-0.61). However, there was no statistically significant difference in genotype or allele frequency between the two groups (HF-SSNHL and AF-SSNHL) and the control group. Conclusion: The αENaC p. Ala663Thr gene polymorphism plays different roles in different types of SSNHL.
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Affiliation(s)
- Jialei Chen
- Department of Pathology and Pathophysiology, Chongqing Medical University, Chongqing, China
| | - Jing He
- Department of Otorhinolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jing Luo
- Department of Pathology and Pathophysiology, Chongqing Medical University, Chongqing, China
| | - Shixun Zhong
- Department of Otorhinolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Quade BN, Parker MD, Occhipinti R. The therapeutic importance of acid-base balance. Biochem Pharmacol 2021; 183:114278. [PMID: 33039418 PMCID: PMC7544731 DOI: 10.1016/j.bcp.2020.114278] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023]
Abstract
Baking soda and vinegar have been used as home remedies for generations and today we are only a mouse-click away from claims that baking soda, lemon juice, and apple cider vinegar are miracles cures for everything from cancer to COVID-19. Despite these specious claims, the therapeutic value of controlling acid-base balance is indisputable and is the basis of Food and Drug Administration-approved treatments for constipation, epilepsy, metabolic acidosis, and peptic ulcers. In this narrative review, we present evidence in support of the current and potential therapeutic value of countering local and systemic acid-base imbalances, several of which do in fact involve the administration of baking soda (sodium bicarbonate). Furthermore, we discuss the side effects of pharmaceuticals on acid-base balance as well as the influence of acid-base status on the pharmacokinetic properties of drugs. Our review considers all major organ systems as well as information relevant to several clinical specialties such as anesthesiology, infectious disease, oncology, dentistry, and surgery.
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Affiliation(s)
- Bianca N Quade
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, The State University of New York, The University at Buffalo, Buffalo, NY 14203, USA; Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA; State University of New York Eye Institute, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA.
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Distal renal tubular acidosis: genetic causes and management. World J Pediatr 2019; 15:422-431. [PMID: 31079338 DOI: 10.1007/s12519-019-00260-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/12/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Distal renal tubular acidosis (dRTA) is a kidney tubulopathy that causes a state of normal anion gap metabolic acidosis due to impairment of urine acidification. This review aims to summarize the etiology, pathophysiology, clinical findings, diagnosis and therapeutic approach of dRTA, with emphasis on genetic causes of dRTA. DATA SOURCES Literature reviews and original research articles from databases, including PubMed and Google Scholar. Manual searching was performed to identify additional studies about dRTA. RESULTS dRTA is characterized as the dysfunction of the distal urinary acidification, leading to metabolic acidosis. In pediatric patients, the most frequent etiology of dRTA is the genetic alteration of genes responsible for the codification of distal tubule channels, whereas, in adult patients, dRTA is more commonly secondary to autoimmune diseases, use of medications and uropathies. Patients with dRTA exhibit failure to thrive and important laboratory alterations, which are used to define the diagnosis. The oral alkali and potassium supplementation can correct the biochemical defects, improve clinical manifestations and avoid nephrolithiasis and nephrocalcinosis. CONCLUSIONS dRTA is a multifactorial disease leading to several clinical manifestations. Clinical and laboratory alterations can be corrected by alkali replacement therapy.
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Ren J, Ma F, Zhou Y, Xu A, Zhang J, Ma R, Xiao X. Hearing impairment in type 2 diabetics and patients with early diabetic nephropathy. J Diabetes Complications 2018; 32:575-579. [PMID: 29776866 DOI: 10.1016/j.jdiacomp.2018.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/26/2018] [Accepted: 03/27/2018] [Indexed: 01/20/2023]
Abstract
AIMS The study was to investigate the hearing function in subjects with non-diabetic nephropathy and diabetic nephropathy and analyze related clinical indexes of hearing impairment. METHODS We assessed the hearing function of 30 diabetics (DM group), 30 patients with early diabetic nephropathy (DN group) and 30 healthy subjects (NC group) using pure-tone audiometry, otoacoustic emissions, electronystagmography, caloric test and cervical vestibular evoked myogenic potential (VEMP). RESULTS Pure-tone audiogram demonstrated a deficit at frequencies with elevated threshold in both DM and DN group (p < 0.05). DN group showed a significant deficit with elevated threshold at 250, 8000 Hz in left ear and 8000 Hz in right ear compared to those of DM group (p < 0.05). GHbA1c, waist and ACR were correlated with elevated thresholds. The DPOAE amplitudes of DN group were obviously smaller in the left ear (4 kHz) and right ear (0.75, 2, 4 kHz) while those of DM group were significantly smaller in the right ear (0.75, 4 kHz) than controls (p < 0.05). A larger proportion of subjects with vestibular dysfunction and VEMP response absence were observed in DN group. CONCLUSIONS Type 2 DM and DN patients have shown clinical hearing impairment and vestibular dysfunction. GHbA1c, waist, ACR, BMI, TC and diabetic retinopathy may affect hearing and vestibular function.
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Affiliation(s)
- Jianmin Ren
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China; Institute of Endocrinology and Metabolism, Shandong University, Jinan, China; Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, China
| | - Fufu Ma
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China; Institute of Endocrinology and Metabolism, Shandong University, Jinan, China; Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, China
| | - Yujing Zhou
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China; Institute of Endocrinology and Metabolism, Shandong University, Jinan, China; Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, China
| | - Anting Xu
- Department of Otolaryngology, The Second Hospital of Shandong University, Jinan, China
| | - Jianjian Zhang
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China; Institute of Endocrinology and Metabolism, Shandong University, Jinan, China; Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, China; Department of Internal Medicine, The Second People's Hospital of Jinan, China
| | - Rong Ma
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China; Institute of Endocrinology and Metabolism, Shandong University, Jinan, China; Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, China
| | - Xiaoyan Xiao
- Department of Nephrology, Qilu Hospital of Shandong University, Jinan, China.
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Hearing loss in hydrocephalus: a review, with focus on mechanisms. Neurosurg Rev 2015; 39:13-24; discussion 25. [DOI: 10.1007/s10143-015-0650-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/09/2014] [Accepted: 04/25/2015] [Indexed: 01/11/2023]
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Abstract
HYPOTHESIS Decalcification of cochlear samples in Morse's solution after methacarn fixation provides greater RNA quantification and morphologic preservation of cochlear structures as compared with EDTA and formic acid decalcifying solutions after methacarn fixation. BACKGROUND A variety of fixatives and decalcifying agents can fragment or chemically alter RNA in samples inhibiting their isolation and quantification. Morphologic alterations can also be observed in light microscopy analyses. The cochlea is embedded in the bone; hence, fixation and decalcification steps are mandatory to obtain histologic sections and preserve the cochlea for morphologic evaluation. METHODS Cochlear samples obtained in a RNase-free environment were processed in 4 combinations of decalcifying agents in combination with methacarn fixation. Samples in Protocols 1, 2, and 3 were fixed in methacarn for 4 hours at 4°C, followed by decalcification at 4°C with Morse's solution, 10% ethylenediaminetetraacetic acid, and 5% formic acid solution, respectively. Samples processed with protocol 4 were decalcified in Morse's solution at 4°C followed by fixation for 4 hours at 4°C. Real-time PCR analysis was performed on total RNA extracted. Histology sections were evaluated for morphology preservation of cochlear structures. RESULTS RNA was isolated in all samples. Relative expression levels were greatest with Protocol 1 and lowest with Protocol 3. Morphology preservation was adequate with Protocols 1, 2, and 3. CONCLUSION Of the 4 protocols evaluated, methacarn fixation followed by decalcification in Morse's solution provided the greatest genetic expression levels as well as the best tissue morphology preservation in the cochlea.
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Coey AT, Sahu ID, Gunasekera TS, Troxel KR, Hawn JM, Swartz MS, Wickenheiser MR, Reid RJ, Welch RC, Vanoye CG, Kang C, Sanders CR, Lorigan GA. Reconstitution of KCNE1 into lipid bilayers: comparing the structural, dynamic, and activity differences in micelle and vesicle environments. Biochemistry 2011; 50:10851-9. [PMID: 22085289 PMCID: PMC3259855 DOI: 10.1021/bi2009294] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
KCNE1 (minK), found in the human heart and cochlea, is a transmembrane protein that modulates the voltage-gated potassium KCNQ1 channel. While KCNE1 has previously been the subject of extensive structural studies in lyso-phospholipid detergent micelles, key observations have yet to be confirmed and refined in lipid bilayers. In this study, a reliable method for reconstituting KCNE1 into lipid bilayer vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho(1'-rac-glycerol) (sodium salt) (POPG) was developed. Microinjection of the proteoliposomes into Xenopus oocytes expressing the human KCNQ1 (K(V)7.1) voltage-gated potassium channel led to nativelike modulation of the channel. Circular dichroism spectroscopy demonstrated that the percent helicity of KCNE1 is significantly higher for the protein reconstituted in lipid vesicles than for the previously described structure in 1.0% 1-myristoyl-2-hydroxy-sn-glycero-3-phospho(1'-rac-glycerol) (sodium salt) (LMPG) micelles. SDSL electron paramagnetic resonance spectroscopic techniques were used to probe the local structure and environment of Ser28, Phe54, Phe57, Leu59, and Ser64 of KCNE1 in both POPC/POPG vesicles and LMPG micelles. Spin-labeled KCNE1 cysteine mutants at Phe54, Phe57, Leu59, and Ser64 were found to be located inside POPC/POPG vesicles, whereas Ser28 was found to be located outside the membrane. Ser64 was shown to be water inaccessible in vesicles but found to be water accessible in LMPG micelle solutions. These results suggest that key components of the micelle-derived structure of KCNE1 extend to the structure of this protein in lipid bilayers but also demonstrate the need to refine this structure using data derived from the bilayer-reconstituted protein to more accurately define its native structure. This work establishes the basis for such future studies.
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Affiliation(s)
- Aaron T. Coey
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | - Indra D. Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | | | - Kaylee R. Troxel
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | - Jaclyn M. Hawn
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | - Max S. Swartz
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | | | - Ro-jay Reid
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
| | - Richard C. Welch
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Carlos G. Vanoye
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Congbao Kang
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio
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Inner ear abnormalities in four patients with dRTA and SNHL: clinical and genetic heterogeneity. Pediatr Nephrol 2009; 24:2147-53. [PMID: 19639346 DOI: 10.1007/s00467-009-1261-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 06/09/2009] [Accepted: 06/09/2009] [Indexed: 12/22/2022]
Abstract
A significant number of patients affected by autosomal recessive primary distal renal tubular acidosis (dRTA) manifest sensorineural hearing loss (SNHL). Mutations in ATP6V1B1 are associated with early onset SNHL, whereas ATP6V0A4 mutations have been described in dRTA and late-onset SNHL. Enlarged vestibular aqueduct (EVA) was described in patients with recessive dRTA and SNHL, and recently, this abnormality has been associated with mutations in the ATP6V1B1 gene. In our study, we evaluated the presence of inner-ear abnormalities in four patients affected by dRTA and SNHL, characterized by molecular analysis. Two patients affected by severe dRTA with early onset SNHL showed the same mutation in the ATP6V1B1 gene and bilateral EVA with a different degree of severity. The other two presented similar clinical manifestations of dRTA and different mutations in the ATP6V0A4 gene: one patient, showing EVA, developed an early SNHL, whereas in the other one, the SNHL appeared in the second decade of life and the vestibular aqueduct was normal. Our study confirms the association of EVA and mutations in the ATP6V1B1 gene and demonstrates that mutations in the ATP6V0A4 gene can also be associated with EVA probably only when the SNHL has an early onset. The pathophysiology of SNHL and EVA are still to be defined.
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Verdel BM, van Puijenbroek EP, Souverein PC, Leufkens HGM, Egberts ACG. Drug-related nephrotoxic and ototoxic reactions : a link through a predictive mechanistic commonality. Drug Saf 2009; 31:877-84. [PMID: 18759511 DOI: 10.2165/00002018-200831100-00006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND Drug-induced ototoxicity is a subject of interest because many diseases are treated with drugs that have potential toxic effects on the ear. There is evidence that both inner ear and kidney tissue are immunologically, biochemically and functionally related. It has been suggested that drugs that influence the transport of sodium and/or potassium change ionic homeostasis in the inner ear and, hence, induce functional disturbances such as hearing loss, tinnitus and vertigo. OBJECTIVES To assess whether renal suspected adverse drug reactions (sADRs) have predictive value for ear and labyrinth adverse drug reactions (ADRs) and whether drug classes involved have influence ion transport systems. STUDY DESIGN Data were obtained from the Netherlands Pharmacovigilance Centre Lareb. The study base comprised all reports of sADRs up until 1 January 2007. Cases were all sADRs for relevant renal disorders and all sADRs for relevant ear disorders. All other reported sADRs were selected as 'non-cases'. The relationship between drug classes and renal, ear and labyrinth sADRs was evaluated by calculating reporting odds ratios (RORs). An ROR > or = 1.50 was regarded as a cut-off value for an association. Drug classes were classified into four groups: (A) ROR kidney <1.50 and ROR ear <1.50 or no reports on ear sADRs (reference group); (B) ROR kidney <1.50 and ROR ear > or = 1.50; (C) ROR kidney > or = 1.50 and ROR ear <1.50 or no reports on ear sADRs; and (D) ROR kidney > or = 1.50 and ROR ear > or = 1.50. For each group, we calculated odds ratios (ORs) for the association between the group classification and the effect on ion channels/ion transport systems in kidney and ear tissues. RESULTS Of 193 drug classes with relevant ADRs for renal disorders, 120 drug classes also had reports on ototoxic reactions. Fourteen out of 120 drug classes had an ROR > or = 1.50 for the association between the drug class and both renal and ear sADRs. Among these drug classes were several with a well known ability to induce renal (adverse) effects and ear and labyrinth disorders, such as loop diuretics, aminoglycosides and quinine. We found that one mechanistic commonality of the drug classes mentioned in the reports was the ability to affect ion transport systems. The percentage of drugs having this property differed between the four groups. The ORs for groups D and B were significantly higher compared with the reference group (OR 12.2, 95% CI 3.0, 30.5 and OR 8.7, 95% CI 2.4, 18.7, respectively), whereas there was no association for group C. CONCLUSION Our data suggest that renal sADRs as such are not a marker for drug-induced ear and labyrinth disorders. However, the ability of drugs to act on ion channels or ion transport systems and, therefore, have an influence on ionic homeostasis in the kidney and ear might be a predictor for the possible occurrence of drug-related ototoxicity.
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Affiliation(s)
- Bertha Maria Verdel
- Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, the Netherlands.
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Kang C, Tian C, Sönnichsen FD, Smith JA, Meiler J, George AL, Vanoye CG, Kim HJ, Sanders CR. Structure of KCNE1 and implications for how it modulates the KCNQ1 potassium channel. Biochemistry 2008; 47:7999-8006. [PMID: 18611041 DOI: 10.1021/bi800875q] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
KCNE1 is a single-span membrane protein that modulates the voltage-gated potassium channel KCNQ1 (K V7.1) by slowing activation and enhancing channel conductance to generate the slow delayed rectifier current ( I Ks) that is critical for the repolarization phase of the cardiac action potential. Perturbation of channel function by inherited mutations in KCNE1 or KCNQ1 results in increased susceptibility to cardiac arrhythmias and sudden death with or without accompanying deafness. Here, we present the three-dimensional structure of KCNE1. The transmembrane domain (TMD) of KCNE1 is a curved alpha-helix and is flanked by intra- and extracellular domains comprised of alpha-helices joined by flexible linkers. Experimentally restrained docking of the KCNE1 TMD to a closed state model of KCNQ1 suggests that KCNE1 slows channel activation by sitting on and restricting the movement of the S4-S5 linker that connects the voltage sensor to the pore domain. We postulate that this is an adhesive interaction that must be disrupted before the channel can be opened in response to membrane depolarization. Docking to open KCNQ1 indicates that the extracellular end of the KCNE1 TMD forms an interface with an intersubunit cleft in the channel that is associated with most known gain-of-function disease mutations. Binding of KCNE1 to this "gain-of-function cleft" may explain how it increases conductance and stabilizes the open state. These working models for the KCNE1-KCNQ1 complexes may be used to formulate testable hypotheses for the molecular bases of disease phenotypes associated with the dozens of known inherited mutations in KCNE1 and KCNQ1.
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Affiliation(s)
- Congbao Kang
- Department of Biochemitry, Vanderbilt University, Nashville, Tennessee 37232, USA
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Smith JA, Vanoye CG, George AL, Meiler J, Sanders CR. Structural models for the KCNQ1 voltage-gated potassium channel. Biochemistry 2007; 46:14141-52. [PMID: 17999538 DOI: 10.1021/bi701597s] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mutations in the human voltage-gated potassium channel KCNQ1 are associated with predisposition to deafness and various cardiac arrhythmia syndromes including congenital long QT syndrome, familial atrial fibrillation, and sudden infant death syndrome. In this work 3-D structural models were developed for both the open and closed states of human KCNQ1 to facilitate structurally based hypotheses regarding mutation-phenotype relationships. The KCNQ1 open state was modeled using Rosetta in conjunction with Molecular Operating Environment software, and is based primarily on the recently determined open state structure of rat Kv1.2 (Long, S. B., et al. (2005) Science 309, 897-903). The closed state model for KCNQ1 was developed based on the crystal structures of bacterial potassium channels and the closed state model for Kv1.2 of Yarov-Yarovoy et al. ((2006) Proc. Natl. Acad. Sci. U.S.A. 103, 7292-7207). Using the new models for KCNQ1, we generated a database for the location and predicted residue-residue interactions for more than 85 disease-linked sites in both open and closed states. These data can be used to generate structure-based hypotheses for disease phenotypes associated with each mutation. The potential utility of these models and the database is exemplified by the surprising observation that four of the five known mutations in KCNQ1 that are associated with gain-of-function KCNQ1 defects are predicted to share a common interface in the open state structure between the S1 segment of the voltage sensor in one subunit and both the S5 segment and top of the pore helix from another subunit. This interface evidently plays an important role in channel gating.
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Affiliation(s)
- Jarrod A Smith
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232-8725, USA
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15
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Lang F, Vallon V, Knipper M, Wangemann P. Functional significance of channels and transporters expressed in the inner ear and kidney. Am J Physiol Cell Physiol 2007; 293:C1187-208. [PMID: 17670895 DOI: 10.1152/ajpcell.00024.2007] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A number of ion channels and transporters are expressed in both the inner ear and kidney. In the inner ear, K+cycling and endolymphatic K+, Na+, Ca2+, and pH homeostasis are critical for normal organ function. Ion channels and transporters involved in K+cycling include K+channels, Na+-2Cl−-K+cotransporter, Na+/K+-ATPase, Cl−channels, connexins, and K+/Cl−cotransporters. Furthermore, endolymphatic Na+and Ca2+homeostasis depends on Ca2+-ATPase, Ca2+channels, Na+channels, and a purinergic receptor channel. Endolymphatic pH homeostasis involves H+-ATPase and Cl−/HCO3−exchangers including pendrin. Defective connexins (GJB2 and GJB6), pendrin (SLC26A4), K+channels (KCNJ10, KCNQ1, KCNE1, and KCNMA1), Na+-2Cl−-K+cotransporter (SLC12A2), K+/Cl−cotransporters (KCC3 and KCC4), Cl−channels (BSND and CLCNKA + CLCNKB), and H+-ATPase (ATP6V1B1 and ATPV0A4) cause hearing loss. All these channels and transporters are also expressed in the kidney and support renal tubular transport or signaling. The hearing loss may thus be paralleled by various renal phenotypes including a subtle decrease of proximal Na+-coupled transport (KCNE1/KCNQ1), impaired K+secretion (KCNMA1), limited HCO3−elimination (SLC26A4), NaCl wasting (BSND and CLCNKB), renal tubular acidosis (ATP6V1B1, ATPV0A4, and KCC4), or impaired urinary concentration (CLCNKA). Thus, defects of channels and transporters expressed in the kidney and inner ear result in simultaneous dysfunctions of these seemingly unrelated organs.
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Affiliation(s)
- Florian Lang
- Department of Physiology, Eberhard-Karls-University of Tübingen, Gmelinstrasse 5, Tübingen, Germany.
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Chen J, Nathans J. Estrogen-Related Receptor β/NR3B2 Controls Epithelial Cell Fate and Endolymph Production by the Stria Vascularis. Dev Cell 2007; 13:325-37. [PMID: 17765677 DOI: 10.1016/j.devcel.2007.07.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 07/16/2007] [Accepted: 07/18/2007] [Indexed: 11/24/2022]
Abstract
In the mammalian inner ear, endolymph is produced and resorbed by a complex series of epithelia. We show here that estrogen-related receptor beta (ERR-beta; NR3B2), an orphan nuclear receptor, is specifically expressed in and controls the development of the endolymph-producing cells of the inner ear: the strial marginal cells in the cochlea and the vestibular dark cells in the ampulla and utricle. Nr3b2(-/-) strial marginal cells fail to express multiple ion channel and transporter genes, and they show a partial transformation toward the fate of the immediately adjacent Pendrin-expressing epithelial cells. In genetically mosaic mice, Nr3b2(-/-) strial marginal cells produce secondary alterations in gene expression in the underlying intermediate cells and a local loss of strial capillaries. A systematic comparison of transcripts in the WT versus Nr3b2(-/-) stria vascularis has identified a set of genes that is likely to play a role in the development and/or function of endolymph-producing epithelia.
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Affiliation(s)
- Jichao Chen
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Knight VB, Serrano EE. Tissue and species differences in the application of quantum dots as probes for biomolecular targets in the inner ear and kidney. IEEE Trans Nanobioscience 2007; 5:251-62. [PMID: 17181024 DOI: 10.1109/tnb.2006.886551] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Quantum dots (QDs) are useful biological probes because of the increased photostability and quantum efficiency they offer over organic fluorophores. However, toxicity concerns arise because the QD core is composed of cadmium and selenium, metals known to be unsafe for humans and animals. We investigated the feasibility of quantum dots as biological labels for imaging studies of inner ear and kidney, tissues that share a polarized epithelial arrangement and drug susceptibility. We found that methods for labeling the actin cytoskeleton of monolayers of cultured amphibian kidney cells (Xenopus A6) with 565 nm QD conjugates were not feasible with large Xenopus inner ear organs. We then compared the uptake of 565 nm cationic peptide-targeted and nontargeted QDs in live kidney cell lines (amphibian, A6 and XLK-WG; human, HEK-293). Results showed that targeted QDs are internalized by all three kidney cell lines, and that nontargeted CdSe nanocrystals are sequestered only by human kidney cells. CellTracker Red CMTPX confirmed the membrane integrity and viability of HEK-293 cells that internalized QDs. Our results demonstrate species and tissue differences in QD uptake and labeling, and underscore the need for long-term studies of QD toxicity and fate in cells.
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Affiliation(s)
- V Bleu Knight
- Biology Department, New Mexico State University, Las Cruces, NM 88003, USA.
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Kanjhan R, Hryciw DH, Yun CC, Bellingham MC, Poronnik P. Postnatal developmental expression of the PDZ scaffolds Na+ -H+ exchanger regulatory factors 1 and 2 in the rat cochlea. Cell Tissue Res 2005; 323:53-70. [PMID: 16160858 PMCID: PMC1472810 DOI: 10.1007/s00441-005-0051-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2005] [Accepted: 06/28/2005] [Indexed: 01/07/2023]
Abstract
Sensory transduction in the mammalian cochlea requires the maintenance of specialized fluid compartments with distinct ionic compositions. This is achieved by the concerted action of diverse ion channels and transporters, some of which can interact with the PDZ scaffolds, Na(+)-H(+) exchanger regulatory factors 1 and 2 (NHERF-1, NHERF-2). Here, we report that NHERF-1 and NHERF-2 are widely expressed in the rat cochlea, and that their expression is developmentally regulated. Reverse transcription/polymerase chain reaction (RT-PCR) and Western blotting initially confirmed the RNA and protein expression of NHERFs. We then performed immunohistochemistry on cochlea during various stages of postnatal development. Prior to the onset of hearing (P8), NHERF-1 immunolabeling was prominently polarized to the apical membrane of cells lining the endolymphatic compartment, including the stereocilia and cuticular plates of the inner and outer hair cells, marginal cells of the stria vascularis, Reissner's epithelia, and tectorial membrane. With maturation (P21, P70), NHERF-1 immunolabeling was reduced in the above structures, whereas labeling increased in the apical membrane of the interdental cells of the spiral limbus and the inner and outer sulcus cells, Hensen's cells, the inner and outer pillar cells, Deiters cells, the inner border cells, spiral ligament fibrocytes, and spiral ganglion neurons (particularly type II). NHERF-1 expression in strial basal and intermediate cells was persistent. NHERF-2 immunolabeling was similar to that for NHERF-1 during postnatal development, with the exception of expression in the synaptic regions beneath the outer hair cells. NHERF-1 and NHERF-2 co-localized with glial fibrillary acidic protein and vimentin in glia. The cochlear localization of NHERF scaffolds suggests that they play important roles in the developmental regulation of ion transport, homeostasis, and auditory neurotransmission.
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Affiliation(s)
- Refik Kanjhan
- School of Biomedical Sciences, The University of Queensland, St Lucia, 4072, Queensland, Australia.
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Roche JP, Wackym PA, Cioffi JA, Kwitek AE, Erbe CB, Popper P. In silico analysis of 2085 clones from a normalized rat vestibular periphery 3' cDNA library. Audiol Neurootol 2005; 10:310-22. [PMID: 16103642 PMCID: PMC1421512 DOI: 10.1159/000087348] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Accepted: 03/21/2005] [Indexed: 11/19/2022] Open
Abstract
The inserts from 2400 cDNA clones isolated from a normalized Rattus norvegicus vestibular periphery cDNA library were sequenced and characterized. The Wackym-Soares vestibular 3' cDNA library was constructed from the saccular and utricular maculae, the ampullae of all three semicircular canals and Scarpa's ganglia containing the somata of the primary afferent neurons, microdissected from 104 male and female rats. The inserts from 2400 randomly selected clones were sequenced from the 5' end. Each sequence was analyzed using the BLAST algorithm compared to the Genbank nonredundant, rat genome, mouse genome and human genome databases to search for high homology alignments. Of the initial 2400 clones, 315 (13%) were found to be of poor quality and did not yield useful information, and therefore were eliminated from the analysis. Of the remaining 2085 sequences, 918 (44%) were found to represent 758 unique genes having useful annotations that were identified in databases within the public domain or in the published literature; these sequences were designated as known characterized sequences. 1141 sequences (55%) aligned with 1011 unique sequences had no useful annotations and were designated as known but uncharacterized sequences. Of the remaining 26 sequences (1%), 24 aligned with rat genomic sequences, but none matched previously described rat expressed sequence tags or mRNAs. No significant alignment to the rat or human genomic sequences could be found for the remaining 2 sequences. Of the 2085 sequences analyzed, 86% were singletons. The known, characterized sequences were analyzed with the FatiGO online data-mining tool (http://fatigo.bioinfo.cnio.es/) to identify level 5 biological process gene ontology (GO) terms for each alignment and to group alignments with similar or identical GO terms. Numerous genes were identified that have not been previously shown to be expressed in the vestibular system. Further characterization of the novel cDNA sequences may lead to the identification of genes with vestibular-specific functions. Continued analysis of the rat vestibular periphery transcriptome should provide new insights into vestibular function and generate new hypotheses. Physiological studies are necessary to further elucidate the roles of the identified genes and novel sequences in vestibular function.
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Affiliation(s)
- Joseph P. Roche
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisc., USA
| | - P. Ashley Wackym
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisc., USA
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisc., USA
| | - Joseph A. Cioffi
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisc., USA
| | - Anne E. Kwitek
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisc., USA
| | - Christy B. Erbe
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisc., USA
| | - Paul Popper
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisc., USA
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Meyer zum Gottesberge AM, Felix H. Abnormal basement membrane in the inner ear and the kidney of the Mpv17-/- mouse strain: ultrastructural and immunohistochemical investigations. Histochem Cell Biol 2005; 124:507-16. [PMID: 16041630 DOI: 10.1007/s00418-005-0027-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2005] [Indexed: 11/30/2022]
Abstract
The loss of the function of the peroxisomal Mpv17-protein and associated imbalanced radical oxygen species (ROS) homeostasis leads to an early onset of focal segmental glomerulosclerosis and sensorineural deafness associated with severe degeneration of cochlear structures. An excessive enlargement of basal laminae of the stria vascularis capillaries and glomeruli indicates numerous changes in their molecular composition. The basement membrane (BM) of the glomeruli and the stria vascularis are simultaneously affected in early stages of the disease and the lamination, splitting of the membrane and formation of the "basket weaving" seen at the onset of the disease in the kidney are similar to the ultrastructural alterations characteristic for Alporta9s syndrome. The progressive alteration of the BMs is accompanied by irregularity in the distribution of the collagen IV subunits and by an accumulation of the laminin B2(gamma1) in the inner ear and B(beta1) in the kidney. Since Mpv17 protein contributes to ROS homeostasis, further studies are necessary to elucidate downstream signaling molecules activated by ROS. These studies explain the cellular responses to missing Mpv17-protein, such as accumulation of the extracellular matrix, degeneration, and apoptosis in the inner ear.
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Affiliation(s)
- Angela M Meyer zum Gottesberge
- Research Laboratory, Department of Otorhinolaryngology, University of Düsseldorf, Moorenstr, 5, 40225, Dusseldorf, Germany,
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21
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Current World Literature. Curr Opin Nephrol Hypertens 2005. [DOI: 10.1097/01.mnh.0000172731.05865.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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