Nephron Physiology最新文献

{"title":"Disorders of water and acid-base homeostasis.","authors":"Fiona E Karet","doi":"10.1159/000320885","DOIUrl":"https://doi.org/10.1159/000320885","url":null,"abstract":"<p><p>Disorders of water balance lead either to dehydration or overhydration. Because there is an intimate relationship between water and sodium concentration (water generally following salt), one can distinguish hypotonic, isotonic and hypertonic dehydration and the same for overhydration. The vast majority of water balance disorders are acquired. In this article, the focus is on the inherited disorders both of water (nephrogenic diabetes insipidus) and acid-base balance. Both acidosis and alkalosis can arise from primary tubular ion transport abnormalities. The alkaloses are usually secondary to salt handling problems, whereas the renal tubular acidoses are often a consequence of primary abnormalities of acid-base transporters.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 1","pages":"p28-34"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000320885","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29464972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyponatremia and inflammation: the emerging role of interleukin-6 in osmoregulation.","authors":"Reinout M Swart,&nbsp;Ewout J Hoorn,&nbsp;Michiel G Betjes,&nbsp;Robert Zietse","doi":"10.1159/000322238","DOIUrl":"https://doi.org/10.1159/000322238","url":null,"abstract":"<p><p>Although hyponatremia is a recognized complication of several inflammatory diseases, its pathophysiology in this setting has remained elusive until recently. A growing body of evidence now points to an important role for interleukin-6 in the non-osmotic release of vasopressin. Here, we review this evidence by exploring the immuno-neuroendocrine pathways connecting interleukin-6 with vasopressin. The importance of these connections extends to several clinical scenarios of hyponatremia and inflammation, including hospital-acquired hyponatremia, postoperative hyponatremia, exercise-associated hyponatremia, and hyponatremia in the elderly. Besides insights in pathophysiology, the recognition of the propensity for antidiuresis during inflammation is also important with regard to monitoring patients and selecting the appropriate intravenous fluid regimen, for which recommendations are provided.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 2","pages":"45-51"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000322238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29568736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selective blockade of oxytocin and vasopressin V(1a) receptors in anaesthetised rats: evidence that activation of oxytocin receptors rather than V(1a) receptors increases sodium excretion.","authors":"D G Shirley,&nbsp;M F Walter,&nbsp;B D Keeler,&nbsp;N J Waters,&nbsp;S J Walter","doi":"10.1159/000320290","DOIUrl":"https://doi.org/10.1159/000320290","url":null,"abstract":"<p><strong>Background: </strong>Although it is known that moderate-to-high doses of the neurohypophysial hormones oxytocin and vasopressin are natriuretic, doubts remain over the identity of the receptors responsible. To address this issue, we have used highly selective antagonists of oxytocin and vasopressin receptors in animals with elevated endogenous circulating levels of the 2 hormones.</p><p><strong>Methods: </strong>Rats were anaesthetised and prepared surgically for clearance studies, thereby raising plasma oxytocin and vasopressin concentrations. Sodium excretion, glomerular filtration rate and lithium clearance (an index of end-proximal fluid delivery) were measured: first during a control period, then after administration of the selective oxytocin receptor antagonist desGly-NH(2),d(CH(2))(5)[D-Trp(2),Thr(4),Dap(5)]OVT, the selective vasopressin V(1a) receptor antagonist d(CH(2))(5)[Tyr(Me)(2),Dab(5)]AVP, or vehicle alone.</p><p><strong>Results: </strong>Absolute and fractional sodium excretion fell in rats given the oxytocin antagonist (by 32 and 27%, respectively, compared with corresponding values in vehicle-infused rats), but not in those given the V(1a) antagonist or vehicle. Antinatriuresis was associated with a small reduction in the ratio of sodium clearance to lithium clearance (an index of the fraction of distally delivered sodium that escapes reabsorption in the distal nephron).</p><p><strong>Conclusions: </strong>These results corroborate previous studies showing that activation of oxytocin receptors increases sodium excretion and imply that the natriuretic effect of elevated plasma vasopressin concentrations results from stimulation of oxytocin receptors.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"117 3","pages":"p21-6"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000320290","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29464466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disorders of the renal proximal tubule.","authors":"Arend Bökenkamp,&nbsp;Michael Ludwig","doi":"10.1159/000320880","DOIUrl":"https://doi.org/10.1159/000320880","url":null,"abstract":"<p><p>Following glomerular filtration, the bulk of solutes are reabsorbed in the proximal tubule to prevent excessive losses of vital metabolites. In this nephron segment, reabsorption is largely active via dedicated transporters. Hereditary defects in proximal tubular function are characterized by malabsorption affecting amino acids, glucose, potassium, phosphate, bicarbonate, low-molecular-weight proteins and other solutes handled by this nephron segment. Dysfunction may be isolated or generalized (Fanconi syndrome). Defects in specific transporters lead to increased urinary excretion of substrates, which are often diagnostic. In others, extrarenal gene expression causes a multisystem phenotype. In this review, we will give a short overview of the molecular genetics, clinical picture, pathophysiology and treatment of genetically defined proximal tubulopathies.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 1","pages":"p1-6"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000320880","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29464467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amelogenesis imperfecta and nephrocalcinosis syndrome: a case report and review of the literature.","authors":"Hercílio Martelli-Júnior,&nbsp;Pedro Eleutério dos Santos Neto,&nbsp;Sibele Nascimento de Aquino,&nbsp;Carolina Carvalho de Oliveira Santos,&nbsp;Sabina Pena Borges,&nbsp;Eduardo Araujo Oliveira,&nbsp;Marcio Ajudarte Lopes,&nbsp;Ricardo D Coletta","doi":"10.1159/000322828","DOIUrl":"https://doi.org/10.1159/000322828","url":null,"abstract":"<p><p>Amelogenesis imperfecta (AI) is a group of hereditary disorders that affect the quality and/or quantity of dental enamel. This paper describes the clinicopathological features of a patient who was born of consanguineous parents and who presented with oral alterations, including yellow and misshapen teeth, intrapulpal calcifications, delayed tooth eruption, and gum enlargement. Scanning electron microscopy of the teeth revealed hypoplastic enamel, and a renal ultrasound detected bilateral nephrocalcinosis, leading to a diagnosis of AI and nephrocalcinosis syndrome. Since nephrocalcinosis is often asymptomatic and can be associated with impaired renal function, dentists who see children with generalized and thin hypoplastic AI should consider a renal ultrasound scan and referral to a nephrologist, if appropriate. Children with nephrocalcinosis should also be considered for a dental check.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 3","pages":"p62-5"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000322828","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29582534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abstracts of the 2nd Joint Meeting of the French Society of Nephrology and the UK Renal Association Entente Cordiale. February 10-11, 2011. Paris, France.","authors":"","doi":"10.1159/000327892","DOIUrl":"https://doi.org/10.1159/000327892","url":null,"abstract":"","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 Suppl 2 ","pages":"p1-20"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000327892","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30022543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Renal stone disease: a commentary on the nature and significance of Randall's plaque.","authors":"A P Evan,&nbsp;R J Unwin,&nbsp;J C Williams","doi":"10.1159/000330255","DOIUrl":"https://doi.org/10.1159/000330255","url":null,"abstract":"In this short follow-up commentary to the recent minireview on renal stone disease by Johri et al. [1], we seek to clarify one aspect of their review that is covered only briefly: current theories of kidney stone formation, including a physicochemical pathway driven by the supersaturation level of dissolved salts in the urine, intratubular crystal adhesion [2], and the Randall's plaque theory for calcium oxalate kidney stone formation and growth [3,4]. Much confusion exists in the literature regarding these theories; in particular it is often assumed that Randall's plaques are connected in some way with adhesion of crystals to tubular epithelial cells. However, Randall proposed no such adhesion of crystals in his original theory, and recent data collected in human stone formers have supported Randall's ideas. Thus, we now need to think of human stone formation in more than one category: The formation of some types of stones clearly involves the adhesion of crystals to the luminal surface of renal tubules, but the formation of stones on Randall's plaques does not involve crystal adhesion to epithelial cells. Finally, it may be that some stones form in the absence of Randall's plaques and also without crystal adhesion as an essential mechanism of stone formation. \u0000 \u0000To better understand these three main potential pathways for stone formation [5], we have produced an illustration (fig. ​(fig.1)1) that depicts the site of initial mineralization along the nephron/renal pelvis, and the final location of the developing stone for each pathway. The three pathways are labeled: ‘free-particle’ stone formation, stone formation on a plug (sometimes referred to as the ‘fixed-particle’ model), and Randall's plaque. In this short paper we will confine our discussion to the Randall's plaque hypothesis and touch only briefly on the other two theories. To give a historical perspective to Randall's plaque hypothesis, we will begin by reviewing his original observations and then link them to our own more recent findings. \u0000 \u0000 \u0000 \u0000Fig. 1 \u0000 \u0000Models of renal stone formation (see text for details). \u0000 \u0000 \u0000 \u0000 \u0000Observations Made by Randall \u0000It was Randall who reasoned from clinical observations in his own clinical practice of stone disease that: (1) there must be an initiating lesion that precedes the formation of a primary renal calculus, and (2) that such an initiating lesion was to be looked for on the renal papilla. It was from these seemingly self-evident facts as a guide that Randall first studied 265 naturally voided stones for the presence of a mural attachment site. In 106, or 40%, of the 265 stones he examined, he found a visible facet on the surface of the stone that was of a different color from the rest of the stone. In his mind this finding strongly supported his original hypothesis that an initiating lesion was required for stone formation. Therefore, Randall decided to obtain direct evidence to test his hypothesis by examining human kidneys, and particularly th","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"119 4","pages":"p49-53"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000330255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30025379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid shear stress induces renal epithelial gene expression through polycystin-2-dependent trafficking of extracellular regulated kinase.","authors":"Daniel Flores,&nbsp;Lorenzo Battini,&nbsp;G Luca Gusella,&nbsp;Rajeev Rohatgi","doi":"10.1159/000321640","DOIUrl":"https://doi.org/10.1159/000321640","url":null,"abstract":"<p><strong>Background: </strong>The cilium and cilial proteins have emerged as principal mechanosensors of renal epithelial cells responsible for translating mechanical forces into intracellular signals. Polycystin-2 (PC-2), a cilial protein, regulates flow/shear-induced changes in intracellular Ca(2+) ([Ca(2+)](i)) and recently has been implicated in the regulation of mitogen-activated protein (MAP) kinases. We hypothesize that fluid shear stress (FSS) activates PC-2 which regulates MAP kinase and, in turn, induces MAP kinase-dependent gene expression, specifically, monocyte chemoattractant protein-1 (MCP-1).</p><p><strong>Methods: </strong>To test this, PC-2 expression was constitutively reduced in a murine inner medullary collecting duct (IMCD3) cell line, and the expression of FSS-induced MCP-1 expression and MAP kinase signaling compared between the parental (PC-2-expressing) and PC-2-deficient IMCD3 cells.</p><p><strong>Results: </strong>FSS induces MAP kinase signaling and downstream MCP-1 mRNA expression in wild-type IMCD3 cells, while inhibitors of MAP kinase prevented the FSS-induced MCP-1 mRNA response. In contradistinction, FSS did not induce MCP-1 mRNA expression in PC-2-deficient cells, but did increase activation of the upstream MAP kinases. Wild-type cells exposed to FSS augmented the nuclear abundance of activated MAP kinase while PC-2-deficient cells did not.</p><p><strong>Conclusions: </strong>PC-2 regulates FSS-induced MAP kinase trafficking into the nucleus of CD cells.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"117 4","pages":"p27-36"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000321640","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29494889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic disorders of NaCl transport in the distal convoluted tubule.","authors":"R Tyler Miller","doi":"10.1159/000320883","DOIUrl":"https://doi.org/10.1159/000320883","url":null,"abstract":"<p><p>The distal convoluted tubule (DCT) reabsorbs 5-10% of filtered Na, and is an important site for regulation of Na balance. Additionally, the amount and composition of the tubular fluid that leaves the DCT affects H and K secretion in more distal nephrin segments. Mutations in five genes whose products are expressed in the DCT demonstrate these points and help to define the mechanisms by which the DCT contributes to control of electrolyte balance and volume. Loss of function mutations in the apical thiazide-sensitive NaCl cotransporter and the basolateral K channel Kir4.1, and activating mutations in the Ca-sensing receptor cause a phenotypically similar salt wasting syndrome. Mutation in two recently identified kinases, WNK1 and WNK4 cause a salt-retaining syndrome through increased apical expression of NaCl cotransporter. Recent studies indicate that these genes are important not only for understanding the physiology of the distal nephron, but that they and others may also contribute to blood pressure variation in the general population.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"118 1","pages":"p15-21"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000320883","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29464468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Familial autosomal recessive renal tubular acidosis: importance of early diagnosis.","authors":"Asaf Vivante,&nbsp;Danny Lotan,&nbsp;Naomi Pode-Shakked,&nbsp;Daniel Landau,&nbsp;Peter Svec,&nbsp;Sheela Nampoothiri,&nbsp;Ishwar Verma,&nbsp;Abdulsalam Abu-Libdeh,&nbsp;Detlef Bockenhauer,&nbsp;Benjamin Dekel,&nbsp;Yair Anikster","doi":"10.1159/000329668","DOIUrl":"https://doi.org/10.1159/000329668","url":null,"abstract":"<p><strong>Background and aims: </strong>Untreated renal tubular acidosis (RTA) can result in severe complications. We reviewed the clinical features of patients with mutations in two genes causing RTA and evaluated their developmental expression assuming that timing, symptom severity and complications may be related to its occurrence.</p><p><strong>Methods: </strong>Clinical data from 16 patients with RTA due to mutations in either ATP6V1B1 or CAII were retrospectively reviewed. Both genes' localization and expression pattern in the developing human kidney were analyzed by real-time polymerase chain reaction and immunostaining.</p><p><strong>Results: </strong>RTA-presenting symptoms were non-specific. Patients with mutations in ATP6V1B1 had earlier presentation (4.9 vs. 11 months, p < 0.041) and longer time to diagnosis than patients with CAII mutations (5.8 vs. 57 months, p < 0.01). Patients with ATP6V1B1 mutations were more likely to develop chronic kidney disease than those with CAII mutations (follow-up GFR values: 89 vs. 110 ml/min/1.73 m2, respectively, p < 0.017), probably secondary to nephrocalcinosis. Both ATP6V1B1 and CAII were expressed early during human nephrogenesis, with relatively higher transcript levels of ATP6V1B1.</p><p><strong>Conclusions: </strong>There is considerable delay in establishing a diagnosis of both types of RTA, supporting the need for earlier biochemical investigation. RTA due to ATP6V1B1 mutations is associated with mild progressive loss of kidney function.</p>","PeriodicalId":18996,"journal":{"name":"Nephron Physiology","volume":"119 3","pages":"p31-9"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000329668","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30083664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}