A geo-chemo-mechanical study of a highly polluted marine system (Taranto, Italy) for the enhancement of the conceptual site model.

The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems.

p14ARF interacts with the focal adhesion kinase and protects cells from anoikis.

The ARF protein functions as an important sensor of hyper-proliferative stimuli restricting cell proliferation through both p53-dependent and -independent pathways. Although to date the majority of studies on ARF have focused on its anti-proliferative role, few studies have addressed whether ARF may also have pro-survival functions. Here we show for the first time that during the process of adhesion and spreading ARF re-localizes to sites of active actin polymerization and to focal adhesion points where it interacts with the phosphorylated focal adhesion kinase. In line with its recruitment to focal adhesions, we observe that hampering ARF function in cancer cells leads to gross defects in cytoskeleton organization resulting in apoptosis through a mechanism dependent on the Death-Associated Protein Kinase. Our data uncover a novel function for p14ARF in protecting cells from anoikis that may reflect its role in anchorage independence, a hallmark of malignant tumor cells.

Light chains removal by extracorporeal techniques in acute kidney injury due to multiple myeloma: a position statement of the Onconephrology Work Group of the Italian Society of Nephrology.

Acute kidney injury (AKI) is a frequent complication of multiple myeloma and is associated with increased short-term mortality. Additionally, even a single episode of AKI can eventually lead to end-stage renal disease (ESRD), significantly reducing quality of life and long-term survival. In the setting of multiple myeloma, severe AKI (requiring dialysis) is typically secondary to cast nephropathy (CN). Renal injury in CN is due to intratubular obstruction from precipitation of monoclonal serum free light chains (sFLC) as well as direct tubular toxicity of sFLC via stimulation of nuclear factor (NF)κB inflammatory pathways. Current mainstays of CN treatment are early removal of precipitating factors such as nephrotoxic drugs, acidosis and dehydration, together with rapid reduction of sFLC levels. Introduction of the proteasome inhibitor bortezomib has significantly improved the response rates in multiple myeloma due to its ability to rapidly reduce sFLC levels and has been referred to as "renoprotective" therapy. As an adjunct to chemotherapy, several new extracorporeal techniques have raised interest as a further means to reduce sFLC concentrations in the treatment of CN. Whether addition of extracorporeal therapies to renoprotective therapy can result in better renal recovery is still a matter of debate and there are currently no guidelines in this field. In this positon paper, we offer an overview of the available data and the authors' perspectives on extracorporeal treatments in CN.

Histological and hormonal changes in the European eel (Anguilla anguilla) after exposure to environmental cocaine concentration.

The aim of this study was the assessment of histological and hormonal changes induced in the European eel from environmental concentrations of cocaine. Silver eels were exposed to 20 ng L(-1) of cocaine during 50 days; at the same time, control, vehicle control and two post-exposure recovery groups (3 and 10 days) were made. The general morphology of the skin and the intestine, and the plasma levels of prolactin, cortisol and dopamine were evaluated. In the skin, cocaine decreased the number and size of mucous cells, increased the thickness of the epidermis and altered the club cells and the basal lamina. In the intestine, cocaine increased the thickness of the epithelium and the number of mucous cells and reactivated the structure of the intestine and of the intestinal musculature. Moreover, cocaine increased plasma prolactin, cortisol and dopamine levels. These results suggest that cocaine induced histological changes, directly and/or through the hormonal changes observed. Considering the complex life cycle of the eel, the changes induced by cocaine in the skin, the intestine and the endocrine system could threaten the ability of the eel to successfully migrate and reproduce.

Early markers of Fabry disease revealed by proteomics.

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency of the lysosomal hydrolase α-galactosidase A (α-GalA) that leads to the intra-lysosomal accumulation of globotriaosylceramide (Gb3) in various organ systems. As a consequence, a multisystems disorder develops, culminating in stroke, progressive renal and cardiac dysfunction. Enzyme replacement therapy (ERT) offers a specific treatment for patients affected by FD, though the monitoring of treatment is hindered by a lack of surrogate markers of response. Remarkably, due to the high heterogeneity of the Fabry phenotype, both diagnostic testing and treatment decisions are more challenging in females than in males; thus, reliable biomarkers for Fabry disease are needed, particularly for female patients. Here, we use a proteomic approach for the identification of disease-associated markers that can be used for the early diagnosis of FD as well as for monitoring the effectiveness of ERT. Our data show that the urinary proteome of Fabry naïve patients is different from that of normal subjects. In addition, biological pathways mainly affected by FD are related to immune response, inflammation, and energetic metabolism. In particular, the up-regulation of uromodulin, prostaglandin H2 d-isomerase and prosaposin in the urine of FD patients was demonstrated; these proteins might be involved in kidney damage at the tubular level, inflammation and immune response. Furthermore, comparing the expression of these proteins in Fabry patients before and after ERT treatment, a decrease of their concentration was observed, thus demonstrating the correlation between the identified markers and the effectiveness of the pharmacological treatment.

Safety and outcome of surgical debridement of insertional Achilles tendinopathy using a transverse (Cincinnati) incision.

This is a prospective analysis on 30 physically active individuals with a mean age of 48.9 years (35 to 64) with chronic insertional tendinopathy of the tendo Achillis. Using a transverse incision, the tendon was debrided and an osteotomy of the posterosuperior corner of the calcaneus was performed in all patients. At a minimum post-operative follow-up of three years, the Victorian Institute of Sports Assessment scale-Achilles tendon scores were significantly improved compared to the baseline status. In two patients a superficial infection of the wound developed which resolved on antibiotics. There were no other wound complications, no nerve related complications, and no secondary avulsions of the tendo Achillis. In all, 26 patients had returned to their pre-injury level of activity and the remaining four modified their sporting activity. At the last appointment, the mean pain threshold and the mean post-operative tenderness were also significantly improved from the baseline (p < 0.001). In patients with insertional tendo Achillis a transverse incision allows a wide exposure and adequate debridement of the tendo Achillis insertion, less soft-tissue injury from aggressive retraction and a safe osteotomy of the posterosuperior corner of the calcaneum.

[Anatomy, physiology and clinical relevance of the connecting tubule]. / Anatomia, fisiologia e importanza clinica del tubulo connettore.

The cortical distal nephron is the site of fine regulation of salt and water excretion by peptide and mineralocorticoid hormones and the site for specific actions of diuretics. Some data suggest that sodium reabsorption and potassium secretion in the distal convoluted tubule and the connecting tubule (CNT) are sufficient to maintain the sodium and potassium balance, with little or no contribution of the collecting duct. The homeostatic role of the sodium and potassium transport systems in the collecting duct can be questioned, especially in conditions where dietary sodium intake is high and potassium intake is low compared with the physiological needs of the organism. The functional expression of epithelial sodium channels (ENaC) in the CNT is sufficient for furosemide-stimulated urinary acidification and identifies the CNT as a major segment in electrogenic urinary acidification. In the outer renal cortex, the CNT returns to the glomerular hilus and contacts the renal afferent arterioles (Af-Art). This morphology is compatible with a cross-talk between the CNT and Af-Art. This novel regulatory mechanism of the renal microcirculation may participate in the vasodilatation observed during high salt intake, perhaps by antagonizing tubuloglomerular feedback. In conclusion, the cortical distal nephron appears to be a complex site for several physiological mechanisms; it is mainly involved in salt and fluid homeostasis and in acid-base balance maintenance. Furthermore, the CNT segment appears to promote a CNT-Af-Art feedback loop.

[Pendrin: physiology, molecular biology and clinical importance]. / La pendrina: fisiologia, biologia molecolare ed importanza clinica.

Pendrin, first identified in 1997, belongs to a superfamily of anion transporters localized in the thyroid gland, inner ear and kidney. Immunohistochemical studies have shown that pendrin is expressed at the apical surface of follicular thyroid cells, where it acts as a Cl-/I- exchanger regulating the chloride transport from the cytoplasm to the colloid space. In the inner ear, pendrin has been found in the stria vascularis of the cochlea and in the endolymphatic duct and sac, where it functions as a Cl- /HCO-3 exchanger. Finally, pendrin is expressed in the kidney, where it is localized in the apical membrane of type-B intercalated cells and non-A, non-B intercalated cells of the cortical collecting ducts and connecting tubules, where it again acts as a Cl /HCO-3 exchanger regulating the acid-base status and chloride homeostasis. Pendrin is encoded by the PDS gene, which is mapped on chromosome 7 (7q22-31.1). Mutations of PDS lead to the Pendred syndrome, a genetic disorder transmitted as an autosomal recessive trait characterized by sensorineural deafness and goiter. It is reasonable to hypothesize that patients affected by Pendred's syndrome may have disturbances of renal function, especially in the regulation of electrolytes and acid-base balance in stress conditions.

A new cross-talk pathway between the renal tubule and its own glomerulus.

The connecting tubule (CNT) of superficial nephrons comes into close contact with the corresponding afferent arteriole of its own glomerulus. Ren et al. demonstrate that this close anatomical configuration is also the site for cross-talk between the CNT and the afferent arteriole. This mechanism is triggered by the entry of sodium through amiloride sodium channels and may antagonize tubuloglomerular feedback.

A crucial nephron segment in acid-base and electrolyte transport: the connecting tubule.

The cortical distal nephron is a heterogenous structure where the fine regulation of electrolyte and water balance takes place. Among the other segments, previous reports have emphasized the importance of the connecting tubule in sodium and potassium renal handling. Kovacikova et al. report that the connecting tubule is also the major segment in electrogenic urinary acidification, thus reinforcing the central role of this segment in overall electrolyte transport.

Acid-base transport in Henle's loop: the effects of reduced renal mass and diabetes.

The loop of Henle (LOH) is an important site of renal acidification. Using the in vivo microperfusion technique of LOH combined with quantitative polymerase chain reaction (PCR) performed on isolated thick ascending limbs (TAL), we demonstrated that the Na + -H + exchanger is the main transport mechanism involved, although a small, but significant contribution from the H+-ATPase also occurs. Among the various Na+-H+ exchanger isoforms we have evidenced that NHE3 is expressed and functionally active along the TAL. Since the LOH is exposed to osmotic stress, bicarbonate transport was also measured under medullary hypotonicity conditions, which led to the stimulation of bicarbonate reabsorption. We demonstrated that the LOH can participate in the tubular adaptation to an increased filtered bicarbonate load by increasing net LOH bicarbonate transport. In this setting, at the molecular level, mRNA and protein abundance of NHE3 were also stimulated, and coincided with an increase in NHE3 activity. Finally, NHE3 expression and abundance was highly stimulated in the early phase of diabetes, which is characterized by increased glomerular filtration rate (GFR).

Use of transgenic mice in acid-base balance studies.

The kidney is essential in maintaining body acid-base status. Recently, the use of transgenic mice has largely contributed to the understanding of the mechanisms involved. Important issues have been addressed in terms of the function of proteins or their regulation. In the proximal tubule, the role of Na+/HCO3-cotransport has been established, although further studies are needed to understand how its mutations lead to renal disease. Na+/H+ exchange has also been extensively studied, and its role in diuretic and natriuretic responses following an increase in blood pressure has been elucidated. The interaction of other transport proteins, such as the Na+/phosphate cotransporter NaPi II-a, with the Na+/H+ exchanger has also been investigated. In the medullary thick ascending limb of Henle's loop (MTAL), a role for NHE1 in transepithelial HCO3- absorption has been demonstrated: basolateral NHE1 controls the function of apical NHE3. As for the distal nephron, the majority of observations suggest that the regulation of H+-ATPase activity in response to acid-base status is mediated by the trafficking of pumps or pump sub-units, especially for the a4 subunit, rather than changes in subunit expression levels. Furthermore, the function of pendrin, a chloride/anion exchanger, has been assessed in response to changes in acid-base status. Important results have been obtained regarding the regulation of proximal tubule transport by several mechanisms, such as microvilli changes and the inducible and endothelial isoform of nitric oxide synthase (NOS). Finally, the interaction of chloride channels and potassium-chloride cotransporter with proton secretion has been evaluated. These findings highlight the importance of knockout animal models in studying kidney regulation of acid-base balance.

[Glomerulo-tubular balance in diabetes mellitus: molecular evidence and clinical consequences]. / Bilancio glomerulo-tubulare nel diabete mellito: evidenze molecolari e conseguenze cliniche.

Diabetes mellitus is fast becoming a world epidemic. About one-third of individuals with diabetes, after 10 yrs, develop diabetic nephropathy, the first cause of end-stage kidney disease. The evolution of diabetic nephropathy can be considered in three stages: glomerular hyperfiltration, microalbuminuria (30-300 mg/24 hr) and proteinuria (>300 mg/24 hr). This study was designed to investigate the tubular basis of glomerular hyperfiltration in early diabetes mellitus. Diabetes was inducted in rats with i.p. streptozotocin (65 mg/kg bw) for 6 days. At the end of the treatment, the glomerular filtration rate (GFR), measured by inulin clearance, had substantially increased in diabetic rats compared with controls. Quantitative polymerase chain reaction (PCR) and Western blot analysis reveal that in diabetic rats compared with controls, mRNA and protein abundance was higher for type 3 sodium/hydrogen exchanger (NHE3) in proximal tubule and ascending limbs of Henle's loop, and higher for bumetanide-sensitive sodium-potassium-2 chloride cotransporter (NKCC2) in ascending limbs of Henle's loop. Western blot analysis confirmed the PCR results. Finally, the abundance of á -ENaC protein was unchanged in diabetic rats compared to controls. These results show that the primary sodium reabsorption increase in proximal tubule reduces salt concentrations at the macula densa. This elicits a tubuloglomerular feedback-dependent increase in single nephron GFR.

Uric acid and the kidney: urate transport, stone disease and progressive renal failure.

In this brief review and update, we try to cover recent developments in our understanding of uric acid transport by the kidney, the contribution of uric acid to renal stone disease, its potential role in progressive renal failure and, most recently, the novel and as yet unexplained link between the urinary glycoprotein Tamm-Horsfall protein (uromodulin) and hyperuricaemia and two inherited forms of renal disease with chronic renal failure.

An overview of divalent cation and citrate handling by the kidney.

Urinary calcium, magnesium and citrate levels are important in promoting or inhibiting renal stone formation. Here we review current information on the tubular handling of these ions. Most filtered calcium is reabsorbed in the proximal tubule and the thick ascending limb (TAL) of the loop of Henle, largely paracellularly; most of the remainder is reabsorbed in the distal tubule, transcellularly. Calcium reabsorption in the TAL and distal tubule is stimulated by parathyroid hormone and vitamin D; other factors influencing its renal handling include extracellular volume status and acid-base balance. Little filtered magnesium is reabsorbed in the proximal tubule; the bulk is reabsorbed paracellularly in the TAL, while most of the remainder is reabsorbed transcellularly in the distal tubule. Dietary intake, peptide hormones and chronic potassium depletion can all influence magnesium reabsorption in the TAL and distal tubule. Most filtered citrate is taken up across the apical membrane of the proximal tubule via a sodium-dicarboxylate co-transporter (NaDC-1). It also enters proximal tubular cells across the basolateral membrane; citrate contributes to the cells' oxidative metabolism. Citrate excretion is affected by acid-base balance, acetazolamide treatment, chronic potassium depletion and urinary excretion of calcium and magnesium. Where possible, we have indicated the mechanisms of these complex interactions.

[New concepts of tubular calcium transport in the kidney: clinical implications]. / Nuove acquisizioni ed implicazioni cliniche del trasporto del calcio a livello del tubulo renale.

The kidney plays an important role in calcium homeostasis. In this review we discuss new concepts in tubular calcium transport, related proteins and the clinical implications of these new findings. Most calcium reabsorption occurs in the proximal tubules via the passive paracellular pathway, but calcium reabsorption also occurs in the thick ascending limb of Henle's loop (50% via the transcellular pathway). Finally, at the level of the distal convoluted tubule and connecting tubule calcium is reabsorbed via the active transcellular route. The Calcium-sensing receptor, localised along the thick ascending limb of Henle's loop, regulates the urinary calcium excretion in response to changes in extracellular calcium concentration. The Epithelial Calcium Channel 1 is a highly Ca2+-sensitive channel that is predominantly present in the connecting tubule. The Calbindin D(28k) is a cytoplasmatic protein expressed in the distal tubule, it is involved both in transcellular calcium diffusion and in the control of intracellular calcium concentration. Heterozygous mutations in the gene for the calcium sensing receptor, which result in a loss of function by the receptor, are associated with familial hypocalciuric hypercalcaemia. Mutations involving a gain of function have been associated with hypocalcaemia with normal serum parathyroid hormone concentration. Bartter's syndrome, caused by a dysfunction of thick ascending limb cells, is associated with calcium wasting. On the contrary, Gitelman's syndrome, caused by a dysfunction of the distal tubule, is characterised by hypocalciuria and hypomagnesemia.

[Tubolopaties associated to hypokalemia]. / Tubolopatie associate a ipopotassemia.

We have described two clinical cases of two young men affected by hypkalemia associated with metabolic alkalosis. The first patient also presented hypercalciucia, normal magnesemia, defect in renal concentrating ability and increased renin activity; in addition he was affected by congenital sensorineural deafness. The diagnosis of Bartter's syndrome was made and it was confirmed by the gene analysis, which revealed a mutation for the beta-subunit of the ClC chloride channels known as barttin. The second case was characterized by hypocalciuria and hypomagnesemia, polyuria and nicturia. The genetic analysis revealed a mutation for the gene encoding the Na+-Cl(-) cotransporter and the diagnosis of Gitelman's syndrome was formulated. We present experimental and clinical evidence to explain, at the molecular level, the differences in calcium and magnesium homeostatis in the two cases. Moreover, we propose different causes to justify the pathogenesis of hypokalemia and the related metabolic alkalosis.

Application of red laser video-rate scanning confocal microscopy to in vivo assessment of tubular function in the rat: selective action of diuretics on tubular diameter.

This study examined the use of a red laser illuminated, video-rate scanning confocal reflection microscopy (VRSCM) system, with improved structural and functional imaging at high temporal resolution, to visualize physiological changes in the kidney in response to pharmacological stimuli. We applied VRSCM to superficial nephrons in vivo and measured temporal changes in the diameter of proximal and/or distal tubular segments in response to the administration of three major classes of diuretics with known selective actions at specific nephron sites. Mannitol caused measurable increases in both proximal and distal tubular diameter, whereas frusemide and hydrochlorothiazide caused dilation of the distal tubules only. The findings indicate that VRSCM is capable of detecting and quantifying predicted dynamic changes in renal tubular diameter.