Search

The search for crystalluria and morphologic analysis of urinary crystals is of interest in the diagnostic evaluation and assessment of efficacy of therapeutic strategies in stone formers. In common calcium oxalate (CaOx) nephrolithiasis, identification of the monohydrate or dihydrate form of CaOx orients toward hyperoxaluria or hypercalciuria as the main lithogenic mechanism, respectively. An unusual high abundance of crystals exclusively made of CaOx monohydrate is highly suggestive of primary hyperoxaluria, the most severe of all types of renal stone diseases. The identification of crystal species such as struvite, cystine, 2,8-dihydroxyadenine, which are not found in normal urine, is indicative of specific pathological conditions, namely, infection stones and hereditary diseases such as cystinuria and dihydroxyadeninuria. Such diseases expose to progressive loss of renal function unless they are prevented by specific therapeutic measures. The presence of crystals made of drugs may entail the risk of kidney dysfunction because of crystallization of the drug or its metabolites.Serial determination of crystalluria, which reflects the activity of stone disease and its response to therapeutic measures, is of major interest in the follow-up of patients suffering from nephrolithiasis. It should be more largely used in clinical practice in most stone formers, still more for the surveillance of patients affected by severe, hereditary renal stone diseases such as primary hyperoxaluria, cystinuria, and dihydroxyadeninuria, where determination of the global crystal volume allows assessing the efficacy of therapeutic measures and optimizing the medical management of the patients., L’étude de la cristallurie et de ses caractéristiques qualitatives et quantitatives est d'un intérêt clinique majeur pour le diagnostic de la maladie lithiasique et l’évaluation de l'efficacité des mesures thérapeutiques proposées aux patients. Dans la lithiase oxalocalcique commune, la forme cristalline, whewellite ou weddellite, oriente respectivement vers une hyperoxalurie ou une hypercalciurie. Une quantité élevée de cristaux de whewellite traduit une forte hyperoxalurie et doit faire rechercher une hyperoxalurie primaire. L'identification de cristaux particuliers tels que la struvite, la cystine, la dihydroxy-2,8-adénine permet le diagnostic de pathologies spécifiques qui exposent à une altération progressive de la fonction rénale lorsqu'elles ne sont pas traitées précocement par des mesures adaptées. La présence de cristaux médicamenteux peut expliquer l'origine d'une insuffisance rénale aiguë développée sous traitement.Au cours du suivi des patients souffrant de lithiase, la détermination de la cristallurie sur des prélèvements sériés est d'un grand intérêt pour la prévention du risque de récidive de calculscar elle reflète l'activité de la maladie lithiasique et sa réponse aux mesures diététiques et thérapeutiques. Elle peut donc bénéficier à la plupart des patients lithiasiques. Elle se doit d’être réalisée chez tout patient souffrant d'une forme héréditaire sévère de lithiase telle que cystinurie, hyperoxalurie primaire ou dihydroxyadéninurie pour en optimiser la prise en charge thérapeutique, la détermination du volume cristallin global dans ces pathologies cristallines sévères permettant d'adapter le traitement médical, d’évaluer l'efficacité des mesures thérapeutiques proposées et de modifier celles-ci en fonction des résultats obtenus.

Alterations in microbiota are known to affect kidney disease conditions. We have previously shown that germ-free conditions exacerbated adenine-induced kidney damage in mice, however, the mechanism by which this occurs has not been elucidated. To explore this mechanism, we examined the influence of germ-free conditions on purine metabolism and renal immune responses involved in the kidney damage. Germ-free mice showed higher expression levels of purine-metabolizing enzymes such as xanthine dehydrogenase, which converts adenine to a nephrotoxic byproduct 2,8-dihydroxyadenine (2,8-DHA). The germ-free mice also showed increased urinary excretion of allantoin, indicating enhanced purine metabolism. Metabolome analysis demonstrated marked differences in the purine metabolite levels in the feces of germ-free mice and mice with microbiota. Furthermore, unlike the germ-free condition, antibiotic treatment did not increase the expression of purine-metabolizing enzymes or exacerbate adenine-induced kidney damage. Considering renal immune responses, the germ-free mice displayed an absence of renal IL-17A expression. However, the adenine-induced kidney damage in wild-type mice was comparable to that in IL-17A-deficient mice, suggesting that IL-17A does not play a major role in the disease condition. Our results suggest that the enhanced host purine metabolism in the germ-free mice potentially promotes the conversion of the administered adenine into 2,8-DHA, resulting in exacerbated kidney damage. This further suggests a role of the microbiota in regulating host purine metabolism.

Background: Eosinophils recognize various stimuli, such as cytokines, chemokines, immunoglobulins, complement, and external pathogens, resulting in their accumulation in mucosal tissues and the progression of inflammation. Eosinophils are also involved in innate Th2-type immune responses mediated through endogenous danger signals, including IL-33, uric acid (UA), or ATP, in non-sensitized mice exposed to environmental allergens. However, the mechanism involved in eosinophil responses to these danger signals remains insufficiently understood. Methods: We examined migration, adhesion, superoxide production and degranulation of human eosinophils. Isolated eosinophils were incubated with monosodium urate (MSU) crystals and ATPγS, a non-hydrolysable ATP analogue. To determine the involvement of P2 or P2Y2 receptors in eosinophil responses to UA and ATP, eosinophils were preincubated with a pan-P2 receptor inhibitor, oxidized ATP (oATP), or anti-P2Y2 antibody before incubation with MSU crystals or ATPγS. Results: MSU crystals induced adhesion of eosinophils to recombinant human (rh)-ICAM-1 and induced production of superoxide. oATP abolished eosinophil responses to MSU crystals, suggesting involvement of endogenous ATP and its receptors. Furthermore, exogenous ATP, as ATPγS, induced migration of eosinophils through a model basement membrane, adhesion to rh-ICAM-1, superoxide generation, and degranulation of eosinophil-derived neurotoxin (EDN). oATP and anti-P2Y2 significantly reduced these eosinophil responses. Conclusions: ATP serves as an essential mediator of functional responses in human eosinophils. Eosinophil responses to ATP may be implicated in airway inflammation in patients with asthma.

The main objective of this study was to prepare a surface plasmon resonance (SPR) sensor for uric acid (UA) detection by using molecularly imprinted nanoparticles as a molecular recognition element. For imprinting, metal ion mediated preorganization was performed to interact between template molecules (UA) and functional monomer by using Fe 3+ ions. UA-imprinted poly (hydroxyethyl methacrylate methacryloyl- l -cysteine methyl ester)-Fe 3+ [poly(HEMA-MAC)-Fe 3+ ] nanoparticles were synthesized by emulsion polymerization in the presence of MAC-Fe 3+ -UA pre-polymerization complex. The characterization of UA-imprinted poly(HEMA-MAC)-Fe 3+ nanoparticles was conducted by Fourier transform infrared spectroscopy (FTIR), elemental analysis, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM) and zeta size analysis. The SPR sensor was prepared by gold surface modification of the sensor with UA-imprinted poly(HEMA-MAC)-Fe 3+ nanoparticles. Characterization of the SPR sensor surface was performed with atomic force microscopy (AFM), contact angle (CA) and optic profilometer measurements. UA sensing ability of the prepared sensor was determined by interacting UA solutions in different concentrations (0.5–40 mg/L) with the SPR sensor. The limit of detection (LOD) and limit of quantification (LOQ) values for the prepared SPR sensor were calculated as 0.247 and 0.825 mg/L for aqueous solution, respectively. The UA-imprinted sensor was also used for UA detection in urine. The results showed the SPR sensor has high selectivity and sensitivity for UA.

The potentiodynamic polymerization of pyrrole is carried out on Pt electrodes using sodium dodecyl sulphate and the coated electrode is employed for sensing of urea non-enzymatically. Employing amperometric and impedimetric methods, urea is estimated in mildly acidic conditions. A detection limit of 40 ?M is obtained along with a linearity of 80-1440 ?M and a sensitivity of 1.11 ?A ?M-1 cm-2 from the amperometric data. The Nyquist plot is employed for the construction of the calibration curve from the impedance analysis. The interference of different compounds such as ascorbic acid, uric acid, sodium chloride and calcium chloride is also analyzed. � 2012 Elsevier B.V.

International audience; The search for crystalluria and morphologic analysis of urinary crystals is of interest in the diagnostic evaluation and assessment of efficacy of therapeutic strategies in stone formers. In common calcium oxalate (CaOx) nephrolithiasis, identification of the monohydrate or dihydrate form of CaOx orients toward hyperoxaluria or hypercalciuria as the main lithogenic mechanism, respectively. An unusual high abundance of crystals exclusively made of CaOx monohydrate is highly suggestive of primary hyperoxaluria, the most severe of all types of renal stone diseases. The identification of crystal species such as struvite, cystine, 2,8-dihydroxyadenine, which are not found in normal urine, is indicative of specific pathological conditions, namely, infection stones and hereditary diseases such as cystinuria and dihydroxyadeninuria. Such diseases expose to progressive loss of renal function unless they are prevented by specific therapeutic measures. The presence of crystals made of drugs may entail the risk of kidney dysfunction because of crystallization of the drug or its metabolites.Serial determination of crystalluria, which reflects the activity of stone disease and its response to therapeutic measures, is of major interest in the follow-up of patients suffering from nephrolithiasis. It should be more largely used in clinical practice in most stone formers, still more for the surveillance of patients affected by severe, hereditary renal stone diseases such as primary hyperoxaluria, cystinuria, and dihydroxyadeninuria, where determination of the global crystal volume allows assessing the efficacy of therapeutic measures and optimizing the medical management of the patients.; L’étude de la cristallurie et de ses caractéristiques qualitatives et quantitatives est d'un intérêt clinique majeur pour le diagnostic de la maladie lithiasique et l’évaluation de l'efficacité des mesures thérapeutiques proposées aux patients. Dans la lithiase oxalocalcique commune, la forme cristalline, whewellite ou weddellite, oriente respectivement vers une hyperoxalurie ou une hypercalciurie. Une quantité élevée de cristaux de whewellite traduit une forte hyperoxalurie et doit faire rechercher une hyperoxalurie primaire. L'identification de cristaux particuliers tels que la struvite, la cystine, la dihydroxy-2,8-adénine permet le diagnostic de pathologies spécifiques qui exposent à une altération progressive de la fonction rénale lorsqu'elles ne sont pas traitées précocement par des mesures adaptées. La présence de cristaux médicamenteux peut expliquer l'origine d'une insuffisance rénale aiguë développée sous traitement.Au cours du suivi des patients souffrant de lithiase, la détermination de la cristallurie sur des prélèvements sériés est d'un grand intérêt pour la prévention du risque de récidive de calculscar elle reflète l'activité de la maladie lithiasique et sa réponse aux mesures diététiques et thérapeutiques. Elle peut donc bénéficier à la plupart des patients lithiasiques. Elle se doit d’être réalisée chez tout patient souffrant d'une forme héréditaire sévère de lithiase telle que cystinurie, hyperoxalurie primaire ou dihydroxyadéninurie pour en optimiser la prise en charge thérapeutique, la détermination du volume cristallin global dans ces pathologies cristallines sévères permettant d'adapter le traitement médical, d’évaluer l'efficacité des mesures thérapeutiques proposées et de modifier celles-ci en fonction des résultats obtenus.

A hybrid nanocomposite consisting of Pt nanoparticles decorated functionalized multiwalled carbon nanotubes (f-MWNT) immobilized with single strand-DNA (ss-DNA) has been devised for the selective detection of dopamine (DA). AFM and TEM analyses show that wrapping of ss-DNA over Pt/f-MWNT reduces the aggregation of the nanotubes arising from van der Waals interaction. In addition to serving as a noncovalent dispersion agent, ss-DNA facilitated electron transfer towards dopamine, as analyzed by cyclic voltammetric studies (CV) and amperometry. The sequence dependency of ss-DNA for DA detection has been analyzed using AC and GT ss-DNA. The hybrid nanocomposite biosensor consisting of AC/ss-DNA exhibits linearity of detection upto ?315 ?M, with a detection limit 0.8 ?M towards dopamine. The best sensing performance with linearity of ?800 ?M and detection limit ?0.45 ?M has been obtained with GT/ss-DNA immobilized Pt/f-MWNT sensor. Further, the nafion coated ss-DNA wrapped Pt/f-MWNT immobilized biosensor exhibits good stability, fast response time (

In this study, cellulose acetate (CA) based hemodialysis membranes were prepared by a dry phase inversion method and the influences of urease immobilization on the clearing performance and protein adsorption capacity of the membranes were investigated. Permeation experiments have shown that modification of CA membranes with urease immobilization not only enhanced the transport rate of urea but also increased the permeation coefficients of uric acid and creatinine by changing the structure of the membrane. Furthermore, the protein adsorption capacity of the CA membranes decreased. On the other hand, the mechanical strength of the modified CA membrane did not change significantly compared with that of the unmodified one. A mathematical model was derived to determine the rate of mass transfer of urea through modified CA membranes. Model predictions along with the experimental data suggest that urease immobilization can be used as an alternative method in preparing CA based hemodialysis membranes with improved transport characteristics and biocompatibility through reduced protein adsorption capacities., İzmir Institute of Technology Grant 2005 İYTE 32

Chemical mechanical planarization of copper disks in hydrogen peroxide and l-arginine based alkaline slurry was investigated. Various commonly proposed inhibitors were screened by static etch rate experiments and only BTA and uric acid were found to be effective in the alkaline pH range, while potassium sorbate was moderately effective. The combination of arginine, hydrogen peroxide and uric acid leads to a more robust polish rate than can be achieved with glycine, hydrogen peroxide and BTA based slurries. The dissolution in presence of uric acid was further studied by potentiodynamic and cyclic polarization experiments which indicate formation of a passivation layer on the copper surface. Silicon dioxide wafers were polished to determine the Cu/silicon dioxide polish rate selectivity in alkaline pH range and a high selectivity (>100) was observed. These results indicate that it is possible to conduct a robust copper CMP with alkaline slurries while maintaining an excellent Cu/silicon dioxide polish rate selectivity. � 2007 Elsevier Ltd. All rights reserved.