Extra-renal locations of the a4 subunit of H+ATPase

Abstract Background Vacuolar-type proton pumps help maintain acid–base homeostasis either within intracellular compartments or at specialised plasma membranes. In mammals they are made up of 13 subunits, which form two functional domains. A number of the subunits have variants that display tissue restricted expression patterns such that in specialised cell types they replace the generic subunits at some sub-cellular locations. The tissue restricted a4 subunit has previously been reported at the plasma membrane in the kidney, inner ear, olfactory epithelium and male reproductive tract. Results In this study novel locations of the a4 subunit were investigated using an Atp6v0a4 knockout mouse line in which a LacZ reporter cassette replaced part of the gene. The presence of a4 in the olfactory epithelium was further investigated and the additional presence of C2 and d2 subunits identified. The a4 subunit was found in the uterus of pregnant animals and a4 was identified along with d2 and C2 in the embryonic visceral yolk sac. In the male reproductive tract a4 was seen in the novel locations of the prostatic alveoli and the ampullary glands as well as the previously reported epididymis and vas deferens. Conclusions The identification of novel locations for the a4 subunit and other tissue-restricted subunits increases the range of unique subunit combinations making up the proton pump. These studies suggest additional roles of the proton pump, indicating a further range of homologue-specific functions for tissue-restricted subunits

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https://www.ester.ee/record=b5505529*es

La représentation de la France dans L'Alouette aux nuages

Aastal, mil Eesti vabariigi iseseisvumisest möödub 100 aastat, on paslik mõtiskleda selle üle, kuidas alguses hakkama saadi. Eesti riigi arenemine jääb 1920.-1930. aastatesse, mis olid ühtlasi kõige pingelised kümnendid Euroopas, tipnedes Teise maailmasõjaga. Kõikide pingete kõrval püüdis ka noor Eesti riik hakkama saada. Olles sajandeid olnud võõrvõimud allutada, tuli nüüd hakata riiki üles rajama. Loomulikult võeti õppust teistelt riikidelt. Eesti riik on eeskujudeks pidanud Inglismaad, Prantsusmaad ja Ameerika Ühendriike ja seda just vabaduseküsimuses, mis on noore riigi jaoks oluline. 1935. aastal ilmus prantsuse kirjaniku Maurice Bedeli raamat „L’Alouette aux nuages“ („Lõoke pilvedes“). Raamatus läheb noor poiss Voldemar Pariisi vabadust õppima. Nimelt on Voldmar pärit autoritaarsest Eestist ja olles filosoofiatudeng Tartu Ülikoolis, võttis ta võimude vastu sõna, mistõttu võimud ta ülikoolist välja viskasid. Nii läheb Voldemar Prantsusmaale kui parima demokraatiakorraga riiki, et õppida saada, mis nii-öelda päris vabaduse kohta, mida tal Eestis ei olnud. See bakalaureusetöö analüüsib, millise pildi loob raamat 1930ndate Prantsusmaast. Et vabadus on juba riigi deviisis, siis on vabaduse ja riigi kirjeldamine võrreldavad. Töö koosnes kolmest peatükist. Esimeses analüüsiti Voldemari mõtted vabadusest ja Prantsusmaast. Teises peatükis vaadeldi, mida kuidas näevad prantslased ise oma riiki ja ühiskonda.. Kolmandas peatükis analüüsiti raamatus leiduvat vabaduseideed kahe teoreetiku, Isaiah Berlini kahe (poliitilise) vabaduse kontseptsiooni ja Jean-Paul Sartre’i eksistentsialismiideede abil.http://www.ester.ee/record=b5144191*es

Las remesas y su efecto en el crecimiento económico del Perú, periodo 2005-2021

El trabajo titulado: “Las remesas y su efecto en el crecimiento económico del Perú, periodo 2005-2021”, busca estimar cual es el efecto de las remesas en el crecimiento económico del Perú. En primer lugar, la metodología aplicada fue el uso del análisis econométrico a través de un modelo log-log. Donde se usó series estadísticas trimestrales de las remesas y crecimiento económico del Perú. Por otro lado, el diseño de la investigación es de tipo explicativo, correlacional no experimental. En segundo lugar, los resultados nos muestran que hubo un aumento de más del doble del monto de remesas de $1440 millones en el año 2005 a$3592 millones para el año 2021. Asimismo, se encontró que un aumento del 1% en las remesas, aumenta el crecimiento económico en un 0.49%. Finalmente, estos resultados se asemejan a varios estudios en los que se utilizaron las variables remesas y crecimiento económico, y de los cuáles se obtiene conclusiones similares.The paper entitled: ""Remittances and their effect on Peru's economic growth, period 2005-2021"", seeks to estimate the effect of remittances on Peru's economic growth. First, the methodology applied was the use of econometric analysis through a log-log model. This model uses quarterly statistical series of remittances and economic growth in Peru. On the other hand, the research design is explanatory, correlational and non-experimental. Secondly, the results show that there was an increase of more than double the amount of remittances from $1440 million in 2005 to$3592 million by 2021. Also, it was found that a 1% increase in remittances increases economic growth by 0.49%. Finally, these results are similar to several studies in which the variables remittances and economic growth were used, and from which similar conclusions were obtainedTesi

An Extended Nomenclature for Mammalian V-ATPase Subunit Genes and Splice Variants

The vacuolar-type H+-ATPase (V-ATPase) is a multisubunit proton pump that is involved in both intra- and extracellular acidification processes throughout the body. Multiple homologs and splice variants of V-ATPase subunits are thought to explain its varied spatial and temporal expression pattern in different cell types. Recently subunit nomenclature was standardized with a total of 22 subunit variants identified. However this standardization did not accommodate the existence of splice variants and is therefore incomplete. Thus, we propose here an extension of subunit nomenclature along with a literature and sequence database scan for additional V-ATPase subunits. An additional 17 variants were pulled from a literature search while 4 uncharacterized potential subunit variants were found in sequence databases. These findings have been integrated with the current V-ATPase knowledge base to create a new V-ATPase subunit catalogue. It is envisioned this catalogue will form a new platform on which future studies into tissue- and organelle-specific V-ATPase expression, localization and function can be based

Making urinary extracellular vesicles a clinically tractable source of biomarkers for inherited tubulopathies using a small volume precipitation method: proof of concept

Abstract: Biomarkers of inherited tubulopathies would be useful for clarifying diagnoses in patients where genetic screening is not readily available or where disease-attributable mutations are not found. Urinary extracellular vesicles (uEVs) obtained by ultracentrifugation can be used as a source of biomarkers for inherited tubulopathies such as Gitelman Syndrome (GS), however, ultracentrifugation requires costly equipment and is thus not usually accessible. In contrast, precipitation methods can extract uEVs using standard laboratory centrifuges, thus making uEVs extracted by this method clinically tractable as a source of biomarkers for GS and other inherited tubulopathies. Here we optimise a precipitation method for extracting urinary extracellular vesicles (uEVs) and provide proof of concept that these uEVs are a source of biomarkers using GS an exemplar tubulopathy. For method optimisation, uEVs were precipitated from fresh and frozen (for up to 6 years), small volume (1–2 mL) urine samples from healthy volunteers and GS patients. Nanoparticle tracking analysis was used to calculate the concentration of uEVs. Thiazide sensitive sodium-chloride cotransporter (NCC) content was determined by densitometry of Western blots. NCC content of uEVs was lower in GS patients (n = 11) than healthy volunteers (n = 12; P = 0.001). Three of four patients clinically suspected for GS, in whom only a single SLC12A3 mutation was identified, had lower uEV NCC content than all healthy volunteers tested. In the clinical setting, sufficient uEVs can be extracted from frozen, small volume urine samples using precipitation methods to distinguish patients with GS from healthy volunteers, and thus this source of uEVs could be utilised as an additional diagnostic test for GS and similar disorders

Renal peroxiredoxin 6 interacts with anion exchanger 1 and plays a novel role in pH homeostasis.

Peroxiredoxin 6 (PRDX6) is one of the six members of the PRDX family, which have peroxidase and antioxidant activity. PRDX6 is unique, containing only one conserved cysteine residue (C47) rather than the two found in other PRDXs. A yeast two-hybrid screen found PRDX6 to be a potential binding partner of the C-terminal tail of anion exchanger 1 (AE1), a Cl(-)/HCO(3)(-) exchanger basolaterally expressed in renal α-intercalated cells. PRDX6 immunostaining in human kidney was both cytoplasmic and peripheral and colocalized with AE1. Analysis of native protein showed that it was largely monomeric, whereas expressed tagged protein was more dimeric. Two methionine oxidation sites were identified. In vitro and ex vivo pull-downs and immunoprecipitation assays confirmed interaction with AE1, but mutation of the conserved cysteine resulted in loss of interaction. Prdx6 knockout mice had a baseline acidosis with a major respiratory component and greater AE1 expression than wild-type animals. After an oral acid challenge, PRDX6 expression increased in wild-type mice, with preservation of AE1. However, AE1 expression was significantly decreased in knockout animals. Kidneys from acidified mice showed widespread proximal tubular vacuolation in wild-type but not knockout animals. Knockdown of PRDX6 by siRNA in mammalian cells reduced both total and cell membrane AE1 levels. Thus, PRDX6-AE1 interaction contributes to the maintenance of AE1 during cellular stress such as during metabolic acidosis.Human kidney sections were prepared by Suzy Haward, Addenbrooke's Human Research Tissue Bank, which is supported by the Cambridge Biomedical Research Centre. We thank Dr. Aron Fisher (Institute for Environmental Science, University of Pennsylvania) for the kind gift of Prdx6−/− mice and reagents, Carsten Wagner (Zurich) for antisera, Jane Clarke (University of Cambridge) for modified pRSET-A vector, and Kamburapola Jayawardena for mass spectrometry (CIMR). This work was funded by the Wellcome Trust (award 088489/Z/09/Z to FEKF and Strategic award 100140/Z/12/Z to the Cambridge Institute for Medical Research), and the Jack Kent Cooke Foundation (scholarship to SLS).This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ki.2015.27

Accuracy of urine pH testing in a regional metabolic renal clinic: is the dipstick accurate enough?

Urine pH is a useful marker for assessing treatment need and efficacy in patients with nephrolithiasis. Though the gold standard of measurement is with a pH electrode, dipsticks offer the convenience of cost, ease of use, and the possibility of patients measuring their own values outside the clinic. The aim of this study was to determine whether dipsticks offer the same accuracy as the electrode. Paired measurements of freshly voided urine pH with both electrode and dipstick were analysed in a multidisciplinary renal clinic. We found that although there was a high Pearson correlation between the samples (0.89, p = 0.001), urine dipstick measurements carried an approximately 1 in 4 risk of producing clinically significant differences (pH differences  > 0.5 pH unit) from meter values. We also found that at high and low urine pH, the dipstick tended to over- and underestimate true pH readings, respectively. Examining the values in the 98 patients where a need for pharmacological urinary pH manipulation was indicated by the true pH, we found 14 who would not have been appropriately treated, and 5 who would have been unnecessarily medicated, if the stick pH value had been used. We conclude that dipstick pH measurement is insufficiently reliable for guiding clinical decision-making

Molecular Approach for Distal Renal Tubular Acidosis Associated AE1 Mutations

The molecular approaches to distal renal tubular acidosis (dRTA) associated AE1 mutations lead us to understand the genetic and pathophysiological aspects of the acidification defects. An unanticipated high value of the urine-blood (U-B) PCO2 after NaHCO3 loading observed in a case of dRTA and southeast Asian ovalocytosis (SAO) might be from a mistarget of the AE1 to the luminal membrane of type A intercalated cells. The mutations of the AE1 gene resulted in SAO and also affected renal acidification function. Notwithstanding, after the NH4Cl loading in 20 individuals with SAO, the acidification in the distal nephron was normal. The presence of both SAO and G701D mutations of AE1 gene would explain the abnormal urinary acidification in the patients with the compound heterozogosity. In terms of the effect of the mutations on trafficking of AE1, truncated kidney isoform (kAE1) of wild-type showed a 'dominant-positive effect' in rescuing the recessive mutant kAE1 (S773P or G701D) trafficking to the plasma membrane, in contrast with the dominant mutant kAE1 (R589H) resulting in a 'dominant-negative effect' when heterodimerized with the wild-type kAE1. It is notable that the dominant mutants kAE1 (R901X or G609R) expression in MDCK cells clearly results in aberrant surface expression with some mutant protein appearing at the apical membrane. These might result in net bicarbonate secretion and increasing U-B PCO2 in the distal nephron. The molecular physiological and genetic approaches have permitted identification of the molecular defects, predominantly in transporter proteins, and should in turn prompt development of novel therapeutic strategies