The pathogenesis of renal ischemia/reperfusion (I/R) injury involves activating several signal transduction cascade systems in endothelial cells. Sphingosine 1-phospate (S1P) maintains endothelial cell integrity and inhibits lymphocyte egress via the specific S1P 1 receptor, and may play a role in reducing ischemic renal injury. We examined the protective effects of a newly identified S1P 1 -selective agonist, SEW2871, on mouse renal I/R injury. Kidneys were harvested 1-4 days after I/R injury for histopathology, immunofluorescence studies, and quantitative real-time reverse transcriptasepolymerase chain reaction analyses to assess the change in gene expression profiles of inflammation-associated cytokines and adhesion molecules. SEW2871 improved renal function with a 40% reduction in plasma creatinine levels (Po0.01) and a significant reduction in tubular necrosis scores (I/R only: 4.370.2 vs I/R þ SEW2871: 2.570.4, Po0.05) 24 h after ischemia. These changes were accompanied by 69% reduction in circulating lymphocytes, and 77 and 66% reduction in infiltrating neutrophils and macrophages in renal outer medulla, respectively (all Po0.01). The mRNA abundance of tumor necrotic factor-a (TNF-a), P-selectin, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) was markedly increased by I/R injury (3.5-, 4.1-, 3.5-, and 4.8-folds, respectively, all Po0.05 vs sham). SEW2871 treatment partially reversed the upregulation of TNF-a, P-selectin, and ICAM-1 (47, 59, 54%, respectively, vs I/R control: 100%, all Po0.05). The reduction in protein expression of TNF-a, P-selectin, and ICAM-1 was further confirmed with immunofluorescence studies. These results suggest that SEW2871 ameliorates renal I/R injury by inhibiting lymphocyte egress and reducing pro-inflammatory molecules. This new class of renoprotective agent shows promise as a novel approach in preventing/treating ischemic acute renal failure.

T cells are thought to be involved in the pathogenesis of renal ischemia-reperfusion injury (IRI); however, earlier studies have not found significant T-cell numbers in the kidney following injury. In this study we test the hypothesis that T cells transiently infiltrate the kidney following reperfusion and leave behind T-cell-derived cytokines such as interferons and interleukins, thus triggering an inflammatory reaction. An early rise of infiltrating T cells was coupled with a decrease in both circulating lymphocytes and CD4+ cells of periarterial lymphocyte aggregates. The renal expression of several chemokines was rapidly and markedly increased by ischemia-reperfusion (IR). Sphingosine-1-phosphate type 1 receptor agonists have been shown to protect kidneys from injury. One of these agonists given before IR significantly reduced histologically assessed renal injury, circulating lymphocyte numbers, and renal T-cell infiltration. This pretreatment did not, however, affect the increase in T-cell chemokines but caused an increase in CD4+ cells in the renal lymphatic system. We conclude that T-cell infiltration is an early event after IRI and is mediated by several chemokines. Sphingosine-1-phosphate receptor agonists reduce renal injury and T-cell infiltration in spite of chemokine generation by inhibiting T-cell mobilization from both renal and extra-renal lymphoid tissue.

The growth of ZnO-on-GaN heterostructures was implemented using the vapor cooling condensation system. The technique thus developed was employed to fabricate both the p-GaN∕n-ZnO:In (p-n) and p-GaN∕i-ZnO∕n-ZnO:In (p-i-n) heterojunction light-emitting diodes (LEDs). A rectifying diodelike behavior was clearly observed from both the p-n and p-i-n heterojunction LEDs, with the forward turn-on voltage of 3V and the reverse breakdown voltage of −15V determined for the p-n heterojunction LEDs, compared to 7 and −23V, respectively, for the p-i-n heterojunction LEDs. Based on the results of photoluminescence and electroluminescence studies conducted on these LED structures, the ZnO layer responsible for the peak emission wavelength of 385nm were also verified experimentally.

Diabetes is associated with renal calcium and magnesium wasting, but the molecular mechanisms of these defects are unknown. We measured renal calcium and magnesium handling and investigated the effects of diabetes on calcium and magnesium transporters in the thick ascending limb and distal convoluted tubule in streptozotocin (STZ)-induced diabetic rats. Rats were killed 2 weeks after inducing diabetes, gene expression of calcium and magnesium transporters in the kidney was determined by real-time polymerase chain reaction, and the abundance of protein was assessed by immunoblotting. Our results showed that diabetic rats had significant increase in the fractional excretion for calcium and magnesium (both P < 0.01), but not for sodium. Reverse transcriptase-polymerase chain reaction revealed significant increases in messenger RNA abundance of transient potential receptor (TRP) V5 (223 +/- 10%), TRPV6 (177 +/- 9%), calbindin-D28k (231 +/- 8%), and TRPM6 (165 +/- 8%) in diabetic rats. Sodium chloride cotransporter was also increased (207 +/- 10%). No change was found in paracellin-1 (cortex: 108 +/- 8%; medulla: 110 +/- 10%). Immunofluorescent studies of renal sections showed significant increase in calbindin-D28k (238 +/- 10%) and TRPV5 (211 +/- 10%), but no changes in paracellin-1 in Western blotting (cortex: 110 +/- 7%; medulla: 99 +/- 7%). Insulin administration completely corrected the hyperglycemia-associated hypercalciuria and hypermagnesiuria, and reversed the increase of calcium and magnesium transporter abundance. In conclusion, our results demonstrated increased renal calcium and magnesium transporter abundance in STZ-induced diabetic rats, which may represent a compensatory adaptation for the increased load of calcium and magnesium to the distal tubule.

No abstract

Furosemide is a loop diuretic agent that has been used to treat hypercalcemia because it increases renal calcium excretion. The effect of furosemide on calcium transport molecules in distal tubules has yet to be investigated. We conducted studies to examine the effects of furosemide on renal calcium excretion and expression of calcium transport molecules in mice. Mice were administered with a single dose of furosemide (15 mg/kg) and examined 4 h later or were given twice-daily furosemide injections for 3 days. To evaluate the effects of volume depletion, drinking water was supplemented with salt. Our results showed that, in acute experiments, furosemide enhanced urinary calcium excretion, which was associated with a significant increase in mRNA levels of TRPV5, TRPV6, and calbindin-D28k but not calbindin-D9k as measured by real-time PCR (TRPV5 and TRPV6 are transient receptor potential vanilloid 5 and 6). Chronic furosemide administration induced threeto fourfold increases in urinary calcium excretion and elevated mRNA levels of TRPV5, TRPV6, calbindin-D28k, and calbindin-D9k without or with salt supplement. Similar upregulation of calcium transport molecules was observed in mice with gentamicin-induced hypercalciuria. Coadministration of chlorothiazide decreased furosemide-induced calciuria, either acutely or chronically, although still accompanied by upregulation of these transport molecules. Immunofluorescent staining studies revealed comparably increased protein abundance in TRPV5 and calbindin-D28k. We conclude that furosemide treatment enhances urinary calcium excretion. Increased abundance of calcium transport molecules in the distal convoluted tubule represents a solute load-dependent effect in response to increased calcium delivery and serves as a compensatory adaptation in the downstream segment. thiazides; TRPV5; TRPV6; calbindin-D28k; calbindin-D9k

To investigate the role of carbonic anhydrase (CA) II on pulmonary CO2 exchange, we analyzed arterial blood gases from CA II-deficient and normal control mice. CA II-deficient mice had a low arterial blood pH (7.18 ± 0.06) and[Formula: see text] concentration ([[Formula: see text]]; 17.5 ± 1.9 meq/l) and a high [Formula: see text](47.4 ± 5.3 mmHg), consistent with mixed respiratory and metabolic acidosis. To eliminate the influence of metabolic acidosis on arterial blood gases, NaHCO3 (4 mmol/kg body weight) was given intraperitoneally, and arterial blood gases were analyzed 4 h later. Normal mice had a small increase in pH and were able to maintain [Formula: see text] and [[Formula: see text]]. The metabolic acidosis in CA II-deficient mice was corrected ([[Formula: see text]], 22.9 ± 2.4 meq/l), and respiratory acidosis became more profound ([Formula: see text], 50.4 ± 2.4 mmHg). These results indicate that CA II-deficient mice have a partial respiratory compensation for metabolic acidosis. We conclude that CA II-deficient mice have a mixed respiratory and metabolic acidosis. It is most likely that CO2 retention in these animals is due to CA II deficiency in both red blood cells and type II pneumocytes.

A second multigeneration family with hereditary lymphedema (LE) secondary to a variant in the planar polarity gene, CELSR1, is described. Dominant inheritance of the variant was discovered using whole‐exome sequencing and confirmed by Sanger sequencing. In contrast to heterozygous males, all heterozygous females showed LE during physical examination albeit variable in severity and age of onset. Lymphscintigraphy in affected females showed previously undescribed lymphatic abnormalities consistent with lymphangiectasia, valve dysfunction, and thoracic duct reflux.