Impact of arteriovenous fistula cannulation on the quality of dialysis

Introduction: Adequate hemodialysis directly improves health. Puncturing an arteriovenous fistula (AVF) and the amount of blood recirculation greatly affect the quality of dialysis. Few studies have assessed the method to cannulate a fistula and its influence on efficiency of hemodialysis. Methods: This prospective pilot study included 14 patients with end‐stage renal failure receiving regular intermittent hemodialysis. Patients received three consecutive treatments with both needles directed upstream then three consecutive treatments with the venous needle directed upstream and the arterial needle directed downstream. With both techniques, the distance between the needles was kept constant at 2.5 cm. Recirculation rate and Kt/V ratio were measured during each treatment using thermodilution and a diascan Fresenius generator. Findings: The 14 patients received 84 hemodialysis sessions: i.e., 8 (57.1%) males and 6 (42.8%) females, mean age 62.3 ± 15.57 years. Results showed that mean recirculation rates and Kt/V did not significantly differ between the two techniques. Discussion: Because no significant difference was found between the two techniques, the direction of insertion of needles should be decided upon on a case‐by‐case basis depending on the anatomy of the AVF and the feasibility of the puncture.     

Contribution of Solutes to Density Stratification in a Meromictic Lake (Waldsee/Germany)

Density differences are the key parameter for stratification stability. We used data from the iron-meromictic Waldsee, Germany, a lignite mine pit lake, to quantify the contribution of single solutes to water density and analyzed the density gradient. Iron meromictic lakes maintain their density gradient through chemical reactions. Hence, quantifying the contributions of separate solutes is essential for understanding the entire process. Based on solute concentrations and literature values of partial molal volumes, substance specific density contributions were quantitatively evaluated. Then, by direct measurements of the density of IHSS Waskish peat fulvic acid, we quantified the density contribution of dissolved organic carbon (DOC). While several solutes contributed to the density throughout the water column, only those substances that occurred at higher concentrations in the anoxic monimolimnion than in the oxic mixolimnion were crucial to sustaining the density difference between the two layers. In Waldsee, the density difference between monimolimnion and mixolimnion was attributed to dissolved Fe²⁺ (0.23?g/L, resulting in a 45?% of the density difference due to solutes) and to the carbonate system (HCO₃ ^?, about 0.16?g/L and CO₂, 0.03?g/L) while Ca²⁺ and DOC delivered only a small contribution. In summer, total density differences were dominated by temperature differences; during winter, solutes sustained meromixis. Finally, we present a complete list of specific density fractions for basically all of the density-relevant substances in fresh waters.     

Casein haplotype structure in five Italian goat breeds

The aim of this work was to investigate the genetic structure of the casein gene cluster in 5 Italian goat breeds and to evaluate the haplotype variability within and among populations. A total of 430 goats from Vallesana, Roccaverano, Jonica, Garganica, and Maltese breeds were genotyped at alphas1-casein (CSN1S1), alphas2-casein, (CSN1S2), beta-casein (CSN2), and kappa-casein (CSN3) loci using several genomic techniques and milk protein analysis. Casein haplotype frequencies were estimated for each breed. Principal component analysis was carried out to highlight the relationship among breeds. Allele and haplotype distributions indicated considerable differences among breeds. The haplotype CSN1S1*F- CSN1S2*F-CSN3*D occurred in all breeds with frequencies >0.100 and was the most common haplotype in the Southern breeds. A high frequency of CSN1S1*0-CSN1S2*C-CSN3*A haplotype was found in Vallesana population (0.162). Principal component analysis clearly separated the Northern and Southern breeds by the first component. The variability of the caprine casein loci and variety of resulting haplotypes should be exploited in the future using specific breeding programs aiming to preserve biodiversity and to select goat genetic lines for specific protein production.     

Statistical search space reduction and two-dimensional data display approaches for UPLC-MS in biomarker discovery and pathway analysis

A new analytical strategy for biomarker recovery from directly coupled ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC Tof MS) data on biofluids is presented and exemplified using a study on hydrazine-induced liver toxicity. A key step in the strategy involves a novel procedure for reducing the spectroscopic search space by differential analysis of cohorts of normal and pathological samples using an orthogonal projection to latent structures discriminant analysis (O-PLS-DA). This efficiently sorts principal discriminators of toxicity from the background of thousands of metabolic features commonly observed in data sets generated by UPLC-MS analysis of biological fluids and is thus a powerful tool for biomarker discovery.     

Stabilization of Ethanol-Based Alumina Suspensions

Al₂O₃ powders have been successfully dispersed in ethanol by varying the suspension acidity. An operational pH (O.pH) was defined to measure the acidity of these ethanol-based suspensions. The isoelectric point of Al₂O₃ in ethanol was at an O.pH of 8. According to Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, suspensions between an O.pH of 3.5–10.5 possessed only attractive inter-particle potential. Suspensions below 3.5 had high ζ potential, fine particle size, and were Newtonian. However, suspensions at high pH were shear thinning and consisted of agglomerates, despite their high ζ potential. The use of citric acid as a dispersant has also been investigated. At an O.pH of 3, optimum additions of citric acid between 0.6 and 1.0 wt% decreased the particle size, resulted in repulsive inter-particle potentials and increased the solid loading capacity to 15 vol% from 2 vol% while maintaining Newtonian behavior and similar viscosity to suspensions at O.pH 2. Addition of citric acid created agglomerated suspensions that were negatively charged at O.pH 10.5 (obtained by adding NH₄OH), but positively charged suspensions at O.pH 13.6 (obtained by adding tetramethylammonium hydroxide).     

Information quality measurement of medical encoding support based on usability

Medical encoding support systems for diagnoses and medical procedures are an emerging technology that begins to play a key role in billing, reimbursement, and health policies decisions. A significant problem to exploit these systems is how to measure the appropriateness of any automatically generated list of codes, in terms of fitness for use, i.e. their quality. Until now, only information retrieval performance measurements have been applied to estimate the accuracy of codes lists as quality indicator. Such measurements do not give the value of codes lists for practical medical encoding, and cannot be used to globally compare the quality of multiple codes lists. This paper defines and validates a new encoding information quality measure that addresses the problem of measuring medical codes lists quality. It is based on a usability study of how expert coders and physicians apply computer-assisted medical encoding. The proposed measure, named ADN, evaluates codes Accuracy, Dispersion and Noise, and is adapted to the variable length and content of generated codes lists, coping with limitations of previous measures. According to the ADN measure, the information quality of a codes list is fully represented by a single point, within a suitably constrained feature space. Using one scheme, our approach is reliable to measure and compare the information quality of hundreds of codes lists, showing their practical value for medical encoding. Its pertinence is demonstrated by simulation and application to real data corresponding to 502 inpatient stays in four clinic departments. Results are compared to the consensus of three expert coders who also coded this anonymized database of discharge summaries, and to five information retrieval measures. Information quality assessment applying the ADN measure showed the degree of encoding-support system variability from one clinic department to another, providing a global evaluation of quality measurement trends.     

Formation of pyridone derivates from maltose and lactose. XII. Investigations on the Maillard-reaction (authors transl)]

Effect of sodium nitrite on cultured FM3A cells, a C3H mouse mammary carcinoma cell line, was examined. The chromosomal preparations demonstrated that severe aberrations were induced in more than 80% of the mitotic plates at 10(-2) M and in nearly 40% at 10(-25) M after 24 and 48 h treatment. According to the results of alkaline sucrose gradient analysis sedimentation profiles of cell DNA treated at as high as 10(-1) M for 24 h scarcely changed from that of control cell DNA. Induction of 8-azaguanine-resistant mutation was demonstrated above 10(-3) M sodium nitrite.     

State-of-the-Art in the Measurement of Volatile Organic Compounds Emitted from Building Products: Results of European Interlaboratory Comparison

Abstract Eighteen laboratories from 10 European countries participated in a comparison organized as part of the VOCEM project, a 2.5-year research collaboration among 4 research institutes and 4 industrial companies. The scope of the project was to improve the procedure used to measure volatile organic compounds (VOC) emitted from building materials and products in small test chambers. The interlaboratory comparison included the GC-MS determination of 5 target compounds from carpet, 8 from polyvinyl chloride (PVC) cushion vinyl and 2 from paint; for the first time, chamber recovery (sinks), homogeneity of solid materials and possible contamination during transport were tested. The results show that the intralaboratory variance (random errors) is much smaller than the interlaboratory variance (systematic errors). Causes of the largest interlaboratory discrepancies were: (i) analytical errors; (ii) losses of the heaviest compounds due to sorption on the chamber walls; and (iii) non homogeneity of the materials. The output of this work concerns both the objective of labelling materials with regard to their VOC emissions and the pre-standard drafted by the European Commitee for Standardization (CEN) for this type of determination.