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Proximal Renal Tubules (proximal + renal_tubule)
Selected AbstractsTopiramate-induced metabolic acidosis: report of two casesDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2001Chun-hung Ko MRCP FHKAM Medical Officer Two children who presented with symptomatic metabolic acidosis after being put on topiramate (TPM) are reported. The first patient was an 11-year-old male with refractory complex partial epilepsy who was put on TPM for 13 months. He developed hyperventilation 1 week after increasing the dose to 300mg/day. Arterial blood gas revealed hyperchloraemic metabolic acidosis with partial respiratory compensation: pH 7.36, PCO2 27.2 mmHg, bicarbonate 14.9 mEq/L, base excess -8.9 mmol/L. Hyperventilation and acidosis resolved after administration of sodium bicarbonate and reduction of the dose of TPM. The second patient was a female who developed increasing irritability at age 16 months and 21 months, each time associated with introduction of TPM and resolved promptly upon withdrawal of the drug. Venous blood gas taken during the second episode revealed pH 7.34, PCO2 37.4 mmHg, bicarbonate 20.4 mEq/L, base excess -4.2 mmol/L. The predominant mechanism of TPM-induced hyperventilation involves inhibition of carbonic anhydrase at the proximal renal tubule, resulting in impaired proximal bicarbonate reabsorption. The occurrence of hyperpnoea or mental status change in any patient who is on TPM should prompt an urgent blood gas sampling, with correction of the acid-base disturbances accordingly. [source] Akt2/PKB,-sensitive regulation of renal phosphate transportACTA PHYSIOLOGICA, Issue 1 2010D. S. Kempe Abstract Aim:, The protein kinase B (PKB)/Akt is known to stimulate the cellular uptake of glucose and amino acids. The kinase is expressed in proximal renal tubules. The present study explored the influence of Akt/PKB on renal tubular phosphate transport. Methods:, The renal phosphate transporter NaPi-IIa was expressed in Xenopus oocytes with or without PKB/Akt and Na+ phosphate cotransport determined using dual electrode voltage clamp. Renal phosphate excretion was determined in Akt2/PKB, knockout mice (akt2,/,) and corresponding wild-type mice (akt2+/+). Transporter protein abundance was determined using Western blotting and phosphate transport by 32P uptake into brush border membrane vesicles. Results:, The phosphate-induced current in NaPi-IIa-expressing Xenopus oocytes was significantly increased by the coexpression of Akt/PKB. Phosphate excretion [,mol per 24 h per g BW] was higher by 91% in akt2,/, than in akt2+/+ mice. The phosphaturia of akt2,/, mice occurred despite normal transport activity and expression of the renal phosphate transporters NaPi-IIa, NaPi-IIc and Pit2 in the brush border membrane, a significantly decreased plasma PTH concentration (by 46%) and a significantly enhanced plasma 1,25-dihydroxyvitamin D3 concentration (by 46%). Moreover, fractional renal Ca2+ excretion was significantly enhanced (by 53%) and bone density significantly reduced (by 11%) in akt2,/, mice. Conclusions:, Akt2/PKB, plays a role in the acute regulation of renal phosphate transport and thus contributes to the maintenance of phosphate balance and adequate mineralization of bone. [source] Application of in situ detection techniques to determine the systemic condition of lymphocystis disease virus infection in cultured gilt-head seabream, Sparus aurata L.JOURNAL OF FISH DISEASES, Issue 2 2009I Cano Abstract Immunohistochemistry (IHC) and in situ hybridization (ISH) techniques have been used for the detection of lymphocystis disease virus (LCDV) in formalin-fixed, paraffin-embedded tissues from gilt-head seabream, Sparus aurata L. Diseased and recovered fish from the same population were analysed. IHC was performed with a polyclonal antibody against a 60-kDa viral protein. A specific digoxigenin-labelled probe, obtained by PCR amplification of a 270-bp fragment of the gene coding the LCDV major capsid protein, was used for ISH. LCDV was detected in skin dermis and gill lamellae, as well as in several internal organs such as the intestine, liver, spleen and kidney using both techniques. Fibroblasts, hepatocytes and macrophages seem to be target cells for virus replication. The presence of lymphocystis cells in the dermis of the skin and caudal fin, and necrotic changes in the epithelium of proximal renal tubules were the only histological alterations observed in fish showing signs of the disease. [source] From history to reality: sodium glucose co-transporter 2 inhibitors , a novel therapy for type 2 diabetes mellitusPRACTICAL DIABETES INTERNATIONAL (INCORPORATING CARDIABETES), Issue 7 2010S Nair MRCP(UK) Abstract The human kidney has a key role in the regulation of blood glucose predominantly by reabsorption of glucose from the glomerular filtrate via sodium glucose co-transporter 2 (SGLT-2) channels. These are expressed in the proximal renal tubules and are blocked by SGLT-2 inhibitors, which are novel pharmacological agents currently in development. Specific SGLT-2 inhibition results in significant increases in renal glucose excretion causing a net calorie loss and consequent weight loss, coupled with a lowering of blood glucose due to removal of glucose from the circulation. The main side effect of SGLT-2 inhibitors appears to be an increase in genital infections, although concerns remain about the potential adverse effects of dehydration and electrolyte imbalance. Dapagliflozin is the SGLT-2 inhibitor that is the furthest along in development, and is currently in phase III clinical trials. In this review article we consider the role of the kidney in glucose homeostasis in normal and diabetic subjects. We also review the history and concept of SGLT-2 inhibition, and discuss the future potential clinical utility of this promising new class of drugs. Copyright © 2010 John Wiley & Sons. [source] | ||||||||||