Effects of angiotensin II on NaPi-IIa co-transporter expression and activity in rat renal cortex

AbstractThe kidney plays a major role in reabsorption of phosphate with the majority occurring in the proximal tubule (PT). The type IIa sodium-phosphate co-transporter (NaPi-IIa) is the main player in PT. The purpose of current study was to determine the effect of angiotensin II (A-II) on membrane expression of NaPi-IIa in the rat renal cortex. A-II (500 ng/kg/min) was chronically infused into the Sprague–Dawley rats by miniosmotic pump for 7 days. The arterial pressure and circulating plasma A-II level along with urine output were markedly increased in A-II rats. There was diuresis but no natriuresis. The phosphate excretion increased sevenfold on day 4 and 5.7-fold on day 7. There was no change in Na-dependent Pi uptake in brush-border membrane (BBM) vesicles between A-II-treated group and control on day 4, however, there was a 43% increase on day 7. Western blot analysis of NaPi-IIa protein abundance showed a parallel pattern: no change after 4 days of treatment and a 48% increase after 7 days of treatment. However, Northern blot analysis of cortical RNA showed no change in NaPi-IIa mRNA abundance on day 7. A-II stimulation of Na/Pi co-transport activity is a result of increases in the expression of BBM NaPi-IIa protein level and that stimulation is most likely mediated by posttranscriptional mechanisms

Quantum phase transition in quantum wires controlled by an external gate

We consider electrons in a quantum wire interacting via a long-range Coulomb potential screened by a nearby gate. We focus on the quantum phase transition from a strictly one-dimensional to a quasi-one-dimensional electron liquid, that is controlled by the dimensionless parameter $n x_0$, where $n$ is the electron density and $x_0$ is the characteristic length of the transverse confining potential. If this transition occurs in the low-density limit, it can be understood as the deformation of the one-dimensional Wigner crystal to a zigzag arrangement of the electrons described by an Ising order parameter. The critical properties are governed by the charge degrees of freedom and the spin sector remains essentially decoupled. At large densities, on the other hand, the transition is triggered by the filling of a second one-dimensional subband of transverse quantization. Electrons at the bottom of the second subband interact strongly due to the diverging density of states and become impenetrable. We argue that this stabilizes the electron liquid as it suppresses pair-tunneling processes between the subbands that would otherwise lead to an instability. However, the impenetrable electrons in the second band are screened by the excitations of the first subband, so that the transition is identified as a Lifshitz transition of impenetrable polarons. We discuss the resulting phase diagram as a function of $n x_0$.Comment: 18 pages, 8 figures, minor changes, published versio

Hyponatremic hypertensive syndrome (HHS) in an 18-month old-child presenting as malignant hypertension: a case report

BACKGROUND: The combination of hyponatremia and renovascular hypertension is called hyponatremic hypertensive syndrome (HHS). Malignant hypertension as a presentation has been reported in adults with HHS but is rare in children. CASE PRESENTATION: An eighteen month-old male presented with drowsiness, sudden onset status epilepticus and blood pressure of 210/160. The electrolytes on admission revealed sodium of 120 mEq/L and potassium of 2.1 mEq/L. The peripheral renin activity (PRA) was 172 ng/ml/min (normal 3–11 ng/ml/min) and serum aldosterone level was 91 ng/dl (normal 4 to 16 ng/dl). Patient underwent angioplasty with no success, followed by surgical correction. Two years since the diagnosis, the blood pressure is controlled with labetolol and amlodipine (at less than sixth of the pre-operative dosages). The PRA is 2.4 ng/ml/min and aldosterone 15.5 ng/dl. The child not only had three renal arteries on left but all of them were stenosed which to best of our knowledge has not been described. CONCLUSION: As uncommon as HHS with malignant hypertension may be in adults it is under-reported in children and purpose of the case report is to raise its awareness

Science with the Daksha High Energy Transients Mission

We present the science case for the proposed Daksha high energy transients mission. Daksha will comprise of two satellites covering the entire sky from 1~keV to $>1$~MeV. The primary objectives of the mission are to discover and characterize electromagnetic counterparts to gravitational wave source; and to study Gamma Ray Bursts (GRBs). Daksha is a versatile all-sky monitor that can address a wide variety of science cases. With its broadband spectral response, high sensitivity, and continuous all-sky coverage, it will discover fainter and rarer sources than any other existing or proposed mission. Daksha can make key strides in GRB research with polarization studies, prompt soft spectroscopy, and fine time-resolved spectral studies. Daksha will provide continuous monitoring of X-ray pulsars. It will detect magnetar outbursts and high energy counterparts to Fast Radio Bursts. Using Earth occultation to measure source fluxes, the two satellites together will obtain daily flux measurements of bright hard X-ray sources including active galactic nuclei, X-ray binaries, and slow transients like Novae. Correlation studies between the two satellites can be used to probe primordial black holes through lensing. Daksha will have a set of detectors continuously pointing towards the Sun, providing excellent hard X-ray monitoring data. Closer to home, the high sensitivity and time resolution of Daksha can be leveraged for the characterization of Terrestrial Gamma-ray Flashes.Comment: 19 pages, 7 figures. Submitted to ApJ. More details about the mission at https://www.dakshasat.in

Rescue Of Renal Function In A 3-Year-Old Girl With Goodpasture\u27S Syndrome With A Brief Review Of Literature

Goodpasture\u27s syndrome has been documented in only a handful of children under the age of four. We describe a 3-year-old girl presenting with anaemia and renal failure whose kidney biopsy showed anti-glomerular basement membrane (GBM) disease. She was treated aggressively with pulse steroids, plasmapheresis and monthly infusions of cyclophosphamide. After months of aggressive immunosuppression, her renal function normalized, and her anti-GBM antibody disappeared. A year after the onset, she underwent a second kidney biopsy for persistent proteinuria and hypertension that surprisingly showed focal sclerosing glomerulonephritis, an unreported finding at this age. The biopsy showed deposition of antibody on the GBM despite the fact that anti-GBM antibody had normalized in the serum 5 months earlier. Mycophenolate mofetil was added to the immunosuppression at that point. At her 3-year follow-up, creatinine clearance was 88.4 mL/min/1.73 m2, proteinuria was 408 mg/day and blood pressure was controlled with enalapril 0.2 mg/kg/day. She has not had a relapse or abnormal anti-GBM antibody for 30 months, but her renal prognosis remains guarded. To our knowledge, this is the youngest patient to have a successful rescue of renal function after isolated Goodpasture\u27s syndrome. © 2010 The Author. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved

Effect of angiotensin-II on renal Na+/H+ exchanger-NHE3 and NHE2

AbstractThe purpose of the present study was to determine the effect of angiotensin II (A-II) on membrane expression of Na+/H+ exchange isoforms NHE3 and NHE2 in the rat renal cortex. A-II (500 ng/kg per min) was chronically infused into the Sprague–Dawley rats by miniosmotic pump for 7 days. Arterial pressure and circulating plasma A-II level were significantly increased in A-II rats as compared to control rats. pH-dependent uptake of 22Na+ study in the presence of 50 μM HOE-694 revealed that Na+ uptake mediated by NHE3 was increased ∼88% in the brush border membrane from renal cortex of A-II-treated rats. Western blotting showed that A-II increased NHE3 immunoreactive protein levels in the brush border membrane of the proximal tubules by 31%. Northern blotting revealed that A-II increased NHE3 mRNA abundance in the renal cortex by 42%. A-II treatment did not alter brush border NHE2 protein abundance in the renal proximal tubules. In conclusion, chronic A-II treatment increases NHE3-mediated Na+ uptake by stimulating NHE3 mRNA and protein content

Uric Acid Control in Advanced Chronic Kidney Disease in a Southeastern US Urban Cohort

Abstract OBJECTIVES: Uric acid (UA) control may be insufficient in chronic kidney disease (CKD) patients in the current era. It is unclear, however, whether this is the result of environmental effects, patient anthropometrics or insufficient dosing of medical therapy (allopurinol). METHODS: We have collected data on multiple clinical and laboratory parameters of 114 CKD clinic patients attending the nephrology clinic of the University of Mississippi Medical Center with an estimated glomerular filtration rate <45 mL · min-1 · 1.73 m2. We assessed the correlates of UA levels and the allopurinol doses along with achieved serum UA and urine pH. RESULTS: The cohort consisted of middle-aged to elderly patients with a mean (± standard deviation) age of 62.1 (11.6) years; 45.6% were female, 68.4% were African American and 47.4% had a history of gout. The mean UA level was 7.7 (2.49) mg/dL (range 3.1-16), allopurinol dose was 192 (99) mg/day (range 50-450) and estimated glomerular filtration rate was 23.8 (11.3) mL · min-1 · 1.73 m2. While the overall serum bicarbonate level was 25 (3.2) mEq/L, urine pH was <6 in 60.5% of the cohort. Significant univariate correlates of the administered doses of allopurinol were weight (r 0.317, P = 0.001), body mass index (BMI; r 0.313, P = 0.001), and female sex (r -0.198; P = 0.035). Achieved UA levels correlated directly with BMI (r 0.201, r = 0.036) but inversely with the allopurinol dose (r -0.196; P = 0.036). During logistic regression analysis with stepwise selection, only weight (β 0.313, P = 0.001) and sex (β -0.190, P = 0.039) proved to be predictive of the allopurinol dose; as for the achieved UA level, only BMI (β 0.271, P = 0.006) and the allopurinol dose (β -0.258; P= 0.009) had a significant effect. CONCLUSIONS: In patients with advanced CKD, conventional dosing recommendations for allopurinol are unlikely to suffice in reaching target serum UA goals. In our cohort, larger-than-usual allopurinol doses were well tolerated