Variability in urinary oxalate measurements between six international laboratories

Background. Hyperoxaluria is a major risk factor for kidney stone formation. Although urinary oxalate measurement is part of all basic stone risk assessment, there is no standardized method for this measurement. Methods. Urine samples from 24-h urine collection covering a broad range of oxalate concentrations were aliquoted and sent, in duplicates, to six blinded international laboratories for oxalate, sodium and creatinine measurement. In a second set of experiments, ten pairs of native urine and urine spiked with 10 mg/L of oxalate were sent for oxalate measurement. Three laboratories used a commercially available oxalate oxidase kit, two laboratories used a high-performance liquid chromatography (HPLC)-based method and one laboratory used both methods. Results. Intra-laboratory reliability for oxalate measurement expressed as intraclass correlation coefficient (ICC) varied between 0.808 [95% confidence interval (CI): 0.427-0.948] and 0.998 (95% CI: 0.994-1.000), with lower values for HPLC-based methods. Acidification of urine samples prior to analysis led to significantly higher oxalate concentrations. ICC for inter-laboratory reliability varied between 0.745 (95% CI: 0.468-0.890) and 0.986 (95% CI: 0.967-0.995). Recovery of the 10 mg/L oxalate-spiked samples varied between 8.7 ± 2.3 and 10.7 ± 0.5 mg/L. Overall, HPLC-based methods showed more variability compared to the oxalate oxidase kit-based methods. Conclusions. Significant variability was noted in the quantification of urinary oxalate concentration by different laboratories, which may partially explain the differences of hyperoxaluria prevalence reported in the literature. Our data stress the need for a standardization of the method of oxalate measuremen

Variability in urinary oxalate measurements between six international laboratories

Hyperoxaluria is a major risk factor for kidney stone formation. Although urinary oxalate measurement is part of all basic stone risk assessment, there is no standardized method for this measurement

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

Background: Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. Design: A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Results: Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. Conclusions: This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified

Cyber security of nuclear power plants in the context of international law

Thesis (M.A.)--Özyeğin University, Graduate School of Social Sciences, Department of Institute of Social Sciences Department of Public Law, June 2018.In this study, the processes from the "Atom", which is the smallest building block of the material that was even mentioned by Aristotle, to the first uses of nuclear energy; from what the nuclear energy means in international law to the importance of nuclear energy compared to other energy sources and from humanitarian and military use to basic principles have been examined with a holistic approach. The use of nuclear energy in various areas, for what purposes it is used today and the total nuclear power plants in the world have been tried to be explained in a comparative way. While the international public opinion regards nuclear energy's being cheap and not emitting carbon as an advantage, there have been a serious concerns for the safety and security of nuclear power plants. Among these concerns, with the latest technology, the tendencies of the terrorists to target nuclear power plants that are vulnerable and can cause massive disasters have been the leading reasons. Prominent international organizations such as IAEA, UN and ICJ have been working for the safety and peaceful use of nuclear power plants that are both binding and advisory, such as the Paris Convention, the Vienna Convention and the NPT. Cybersecurity of nuclear power plants has become increasingly important in recent times and is an area where international law couldn't fully form a legal framework. This study, consisting of three parts, examines the development of nuclear energy, international legal principles and cyber security of nuclear power plants, and tries to develop a hypothesis on this subject.Bu çalışmada, Aristoteles'e kadar mazhar olan maddenin en küçük yapı taşı olan 'atom'dan nükleer enerjinin ilk kullanım alanlarına, nükleer enerjinin diğer enerji kaynaklarındaki yerinden uluslararası hukukta ne anlama geldiğine; insani ve askeri kullanım amaçlarından temel ilkelerine kadarki süreç bütünsel bir yaklaşımla irdelenmiştir. Nükleer enerjinin kullanım sahaları, günümüzde hangi amaçlarla kullanıldığı, dünyadaki toplam nükleer santral ünitesi ve neden önemli olduğu mukayeseli bir şekilde izah edilmeye çalışılmıştır. Uluslararası kamuoyu nezdinde nükleer enerjinin ucuz olması ve karbon salınımın olmaması bir avantaj olarak görülürken, nükleer santrallerin emniyet ve güvenliği noktasında ciddi kaygılar ortaya çıkmıştır. Bu kaygıların başında, son zamanlarda gelişen teknolojiyle birlikte terör örgütlerinin daha kırılgan ve büyük facialara yol açabilecek nükleer santraller gibi hedeflere yönelme eğilimleri gelmektedir. Nükleer santrallerin güvenliği ve barışçıl amaçlarla kullanılması yönünde UAEA, BM ve UAD gibi önemli uluslararası kuruluşlar Paris Sözleşmesi, Viyana Sözleşmesi ve NPT gibi hem bağlayıcı hem de tavsiye niteliğinde çalışmalar yürütmüşlerdir. Nükleer santrallerin siber güvenliği ise son zamanlarda gittikçe önem kazanmaktadır ve uluslararası hukukun tam anlamıyla yasal çerçeve oluşturamadığı bir sahadır. Bu durum da uluslararası camiada, bu boşluğu doldurmak üzere yeni hukuki düzenlemeler gerçekleştirmeye sebebiyet vermiştir. Üç bölümden oluşan bu çalışmada, nükleer enerjinin gelişimi, uluslararası hukuki esasları ve nükleer santrallerin siber güvenliği konularını irdeleyerek, bu konu hakkında bir hipotez geliştirilmeye çalışılacaktır