Role of cytochrome P-450 as a source of catalytic iron in cisplatin-induced nephrotoxicity

Role of cytochrome P-450 as a source of catalytic iron in cisplatin-induced nephrotoxicity.BackgroundIron plays a role in free radical-mediated tissue injury, including cisplatin-induced nephrotoxicity. However, the source of iron (catalyzing free radical reactions) is not known. We examined the role of cytochrome P-450 as a source of catalytic iron in cisplatin-induced nephrotoxicity both in vivo and in vitro.MethodsCisplatin-induced acute renal failure was produced in rats by intraperitoneal injection of cisplatin (10mg/kg body wt). Piperonyl butoxide, a cytochrome P-450 inhibitor, was administered intraperitoneally (400mg/kg body wt twice at 48-hr intervals) prior to cisplatin injection. The effects of cisplatin in the absence or presence of piperonyl butoxide on the belomycin-detectable iron, cytochrome P-450 content in the kidney, and renal functional and histological changes were evaluated. In an in vitro study, the effect of cytochrome P-450 inhibitors, cimetidine or piperonyl butoxide, on cisplatin-induced cytotoxicity and catalytic iron release from LLC-PK1 cells was examined.ResultsIn cisplatin-treated rats, there was a marked decrease in the cytochrome P-450 content specifically in the kidney, accompanied by increased bleomycin-detectable iron content in the kidney. Piperonyl butoxide prevented cisplatin-induced loss of cytochrome P-450 as well as the increase of bleomycin-detectable iron in the kidney, along with both functional and histological protection. Both cimetidine and piperonyl butoxide prevented cisplatin-induced increase in bleomycin-detectable iron and cytotoxicity in LLC-PK1 cells. Treatment of cimetidine did not affect cellular uptake of cisplatin.ConclusionCytochrome P-450, a group of heme proteins, may serve as a significant source of catalytic iron in cisplatin-induced nephrotoxicity

In vitro and in vivo evidence suggesting a role for iron in cisplatin-induced nephrotoxicity

In vitro and in vivo evidence suggesting a role for iron in cisplatin-induced nephrotoxicity. Cisplatin is a widely used antineoplastic agent that has nephrotoxicity as a major side effect. The underlying mechanism of this nephrotoxicity is still not well known. Iron has been implicated to play an important role in several models of tissue injury, presumably through the generation of hydroxyl radicals via the Haber-Weiss reaction or other highly toxic free radicals. In the present study we examined the catalytic iron content and the effect of iron chelators in an in vitro model of cisplatin-induced cytotoxicity in LLC-PK1 cells (renal tubular epithelial cells) and in an in vivo model of cisplatin-induced acute renal failure in rats. Exposure of LLC-PK1 cells to cisplatin resulted in a significant increase in bleomycin-detectable iron (iron capable of catalyzing free radical reactions) released into the medium. Concurrent incubation of LLC-PK1 cells with iron chelators including deferoxamine and 1,10-phenanthroline significantly attenuated cisplatin-induced cytotoxicity as measured by lactate dehydrogenase (LDH) release. Bleomycin-detectable iron content was also markedly increased in the kidney of rats treated with cisplatin. Similarly, administration of deferoxamine in rats provided marked functional (as measured by blood urea nitrogen and creatinine) and histological protection against cisplatin-induced acute renal failure. In a separate study, we examined the role of hydroxyl radical in cisplatin-induced nephrotoxicity. Incubation of LLC-PK1 cells with cisplatin caused an increase in hydroxyl radical formation. Hydroxyl radical scavengers, dimethyl sulfoxide, mannitol and benzoic acid, significantly reduced cisplatin-induced cytotoxicity and, treatment with dimethyl sulfoxide or dimethylthiourea provided significant protection against cisplatin-induced acute renal failure. Taken together, our data strongly support a critical role for iron in mediating tissue injury via hydroxyl radical (or a similar oxidant) in this model of nephrotoxicity

Openpit Mine Slope Stability – A Case Study

For profitability steep overall slope angle is essential for openpit mines without endangering the safety for the life time of the pit. Openpits have been designed to depths of 150 to 200 metres. For optimum slope angles of the footwall and the hanging wall of a rock phosphate mine, near Udaipur, Rajasthan , geotechnical investigation covering discontinuity mapping, analysis of data, testing of geo-mechanical properties in laboratory and in in-situ condition were conducted. Slope monitoring was done by precise surveying instruments to give advance warning of impending ground movement. On the basis of geotechnical studies the mine has been designed with an overall slope angle of 33 degrees up to 200 metres depth

Promoter analysis by saturation mutagenesis

Gene expression and regulation are mediated by DNA sequences, in most instances, directly upstream to the coding sequences by recruiting transcription factors, regulators, and a RNA polymerase in a spatially defined fashion. Few nucleotides within a promoter make contact with the bound proteins. The minimal set of nucleotides that can recruit a protein factor is called a cis-acting element. This article addresses a powerful mutagenesis strategy that can be employed to define cis-acting elements at a molecular level. Technical details including primer design, saturation mutagenesis, construction of promoter libraries, phenotypic analysis, data analysis, and interpretation are discussed

Integrating Oceanographic Research Into High School Curricula: Achieving Broader Impacts Through Systems Education Experiences Modules

We describe a framework for incorporating cross-disciplinary oceanographic research into high school curriculum modules and discuss how this framework could be adopted broadly by ocean scientists to build cohesive broader impacts programs nested within individual oceanographic research programs

Characterization of Escherichia coli Phylogenetic Groups Associated with Extraintestinal Infections in South Indian Population

Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra‑intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of infection, expression of virulence factors, antimicrobial resistance patterns, and clinical outcome. This descriptive study was carried out in a multi‑specialty Tertiary Care Hospital.Materials and Methods: A total of 300 E. coli causing ExPEC were studied. Triplex polymerase chain reaction was used to classify the phylogenetic groups; hemolysin production was assessed on sheep blood agar and biofilm production in a microtiter plate assay. Production of extended spectrum of beta‑lactamase (ESBLs) was detected by combination disk method; AmpC was detected by AmpC disk test, Carbapenemase production was detected by modified Hodge test and metallo‑â‑lactamase by metallo‑beta‑lactamases (MBL) E‑test.Results: Of 300 isolates, 61/300 (20 %) belonged to phylogroup A, 27/300 (9%) to phylogroup B1, 104/300 (35%) were B2 and 108/300 (36%) belonged to group D, respectively. Phylogroups B2 and D were the most predominant groups in urinary tract infection and sepsis. Prognoses were better in infections with group A and B1 isolates, and relapses and death were common in infections with B2 and D. Expression of biofilm was greatest in B1 and hemolysin in group B2. Group A and B1 showed higher resistance to ciprofloxacin and were most frequent â‑lactamase (ESBL, AmpC, Carbapenemase and MBL) producers.Conclusions: Phylogenetic group B2 and D were predominant in ExPEC and exhibited least antimicrobial resistance among the groups. Resistance to multiple antibiotics was most prevalent in group A and B1. Regular monitoring of antimicrobial susceptibility in commensal strains is essential as they might transfer the property of antimicrobial resistance to pathogenic strains.Keywords: Drug resistance, Escherichia coli, Extraintestinal infections, Polymerase chain reaction, Phylogenetic group, Virulenc

Human exercise-induced circulating progenitor cell mobilization is nitric oxide-dependent and is blunted in South Asian men

This article is available open access through the publisher’s website. Copyright @ 2010 American Heart Foundation.Objective— Circulating progenitor cells (CPC) have emerged as potential mediators of vascular repair. In experimental models, CPC mobilization is critically dependent on nitric oxide (NO). South Asian ethnicity is associated with reduced CPC. We assessed CPC mobilization in response to exercise in Asian men and examined the role of NO in CPC mobilization per se. Methods and Results— In 15 healthy, white European men and 15 matched South Asian men, CPC mobilization was assessed during moderate-intensity exercise. Brachial artery flow-mediated vasodilatation was used to assess NO bioavailability. To determine the role of NO in CPC mobilization, identical exercise studies were performed during intravenous separate infusions of saline, the NO synthase inhibitor l-NMMA, and norepinephrine.  Flow-mediated vasodilatation (5.8%±0.4% vs 7.9%±0.5%; P=0.002) and CPC mobilization (CD34+/KDR+ 53.2% vs 85.4%; P=0.001; CD133+/CD34+/KDR+ 48.4% vs 73.9%; P=0.05; and CD34+/CD45− 49.3% vs 78.4; P=0.006) was blunted in the South Asian group. CPC mobilization correlated with flow-mediated vasodilatation and l-NMMA significantly reduced exercise-induced CPC mobilization (CD34+/KDR+ −3.3% vs 68.4%; CD133+/CD34+/KDR+ 0.7% vs 71.4%; and CD34+/CD45− −30.5% vs 77.8%; all P<0.001). Conclusion— In humans, NO is critical for CPC mobilization in response to exercise. Reduced NO bioavailability may contribute to imbalance between vascular damage and repair mechanisms in South Asian men.British Heart Foundatio

Informal Action—Adjudication—Rule Making: Some Recent Developments in Federal Administrative Law

Direct energy consumption of ICT hardware is only “half the story.” In order to get the “whole story,” energy consumption during the entire life cycle has to be taken into account. This chapter is a first step toward a more comprehensive picture, showing the “grey energy” (i.e., the overall energy requirements) as well as the releases (into air, water, and soil) during the entire life cycle of exemplary ICT hardware devices by applying the life cycle assessment method. The examples calculated show that a focus on direct energy consumption alone fails to take account of relevant parts of the total energy consumption of ICT hardware as well as the relevance of the production phase. As a general tendency, the production phase is more and more important the smaller (and the more energy-efficient) the devices are. When in use, a tablet computer is much more energy-efficient than a desktop computer system with its various components, so its production phase has a much greater relative importance. Accordingly, the impacts due to data transfer when using Internet services are also increasingly relevant the smaller the end-user device is, reaching up to more than 90 % of the overall impact when using a tablet computer.QC 20140825</p

A genetic algorithm for cocyclic hadamard matrices

A genetic algorithm for finding cocyclic Hadamard matrices is described. Though we focus on the case of dihedral groups, the algorithm may be easily extended to cover any group. Some executions and examples are also included, with aid of Mathematica 4.0