A Novel Neurofilament Light Chain ELISA Validated in Patients with Alzheimer’s Disease,Frontotemporal Dementia,and Subjective Cognitive Decline,and the Evaluation of Candidate Proteins for Immunoassay Calibration

Neurofilament light chain (Nf-L) is a well-known biomarker for axonal damage; however, the corresponding circulating Nf-L analyte in cerebrospinal fluid (CSF) is poorly characterized. We therefore isolated new monoclonal antibodies against synthetic peptides, and these monoclonals were characterized for their specificity on brain-specific intermediate filament proteins. Two highly specific antibodies, ADx206 and ADx209, were analytically validated for CSF applications according to well-established criteria. Interestingly, using three different sources of purified Nf-L proteins, a significant impact on interpolated concentrations was observed. With a lower limit of analytical sensitivity of 100 pg/mL using bovine Nf-L as the calibrator, we were able to quantify the Nf-L analyte in each sample, and these Nf-L concentrations were highly correlated to the Uman diagnostics assay (Spearman rho = 0.97, p < 0.001). In the clinical diagnostic groups, the new Nf-L ELISA could discriminate patients with Alzheimer’s disease (AD, n = 20) from those with frontotemporal lobe dementia (FTD, n = 20) and control samples with subjective cognitive decline (SCD, n = 20). Henceforth, this novel Nf-L ELISA with well-defined specificity and epitopes can be used to enhance our understanding of harmonizing the use of Nf-L as a clinically relevant marker for neurodegeneration in CSF.     

Proteolysates from slaughter-house blood

Previous studies have shown the anticlotting effect of papain on slaughter-house blood to be due to its proteolytic activity on fibrin. This has suggested its possible use in a protein recovery process. Blood proteolysate has been obtained using microbial proteases or papain; the haemolysis of the cells was then effected and the haem extracted with acidified acetone to decolourise the product.     

Airborne Lidar LEANDRE II for Water-Vapor Profiling in the Troposphere. II. First results

The airborne lidar LEANDRE II, described in part I [Appl. Opt. 40, 3450-3461 (2001)], has been flown on the French Atmospheric Research Aircraft to perform lower-troposphere (0-3.5-km) measurements of the water-vapor mixing ratio. We present and discuss the method used for retrieval of the water-vapor mixing ratio and analyze systematic and random measurement errors in relation to instrument design and performance. The results of a series of test flights are presented. With a 0.8-km horizontal resolution and a 300-m vertical resolution, the standard deviation of the measurement error ranges from approximately 0.05 g kg(-1) at 3.5 km to 0.3-0.4 g kg(-1) near the ground, in agreement with the predicted random error. Comparisons with dew-point hygrometer measurements show a vertically averaged difference of ?0.15 g kg(-1), approximately equal to the observed water-vapor variability.     

Beta-binders for Biological Quantitative Experiments

The similarities between biological systems and distributed and mobile systems suggest that the theory of process calculi could be a useful starting point for understanding, if not predicting, the behaviour of complex biological systems.To formally model in vitro or in vivo experiments, appropriate quantitative extensions of process calculi have to be investigated. This paper focuses on Beta-binders, a language of processes with typed interaction sites which has been recently introduced to accurately represent biological entities.Here the syntax and semantics of Beta-binders are enriched to achieve a stochastic version of it, in order to obtain quantitative measures on biological phenomena. The quantitative parameters are derived from typed interaction sites introducing the concept of affinity. The relevance of quantitative reasoning is outlined running a biological example.     

Use of electronic nose and trained sensory panel in the evaluation of tomato quality

In this paper the performances of an electronic nose based on metalloporphyrin‐coated quartz microbalance sensors and of an experienced panel of seven human assessors in the evaluation of gases derived from degradation reactions in tomatoes are presented and discussed. The performances are measured in terms of the capability of both systems to distinguish between samples of different quality coming from conventional and organic production systems. The study deals with the application of pattern recognition techniques based on either multivariate statistical methods (PCA, GPA) or artificial neural networks using a self‐organising map (SOM). The response pattern of the sensor array and the sensory data are analysed and compared using these methods. Similarities in the classification of the data by electronic nose and human sensory profiling are found. © 2000 Society of Chemical Industry     

Enzymic solubilisation of proteins of sardine (sardina pilchardus) by commercial proteases

Enzymic hydrolysis represents a valid method for recovering proteins from by-products and surplus of the food industry, by protein solubilisation. In view of the economic interest in the recovering of protein from poorly utilised species of fish, screening of some commercially available proteolytic enzymes: alcalase, papain and neutrase, was undertaken in order to test the most suitable one for the substrate employed. From the results, it can be concluded that alcalase and papain, at optimum pH and temperature conditions have significant effects on the nitrogen recovery from sardines, giving hydrolysates of high nutritional value and characterised by high solubility.     

Multiplex-touchdown PCR assay for the detection and genotyping of Helicobacter pylori from artificially contaminated sheep milk

Helicobacter pylori (Hp) is an organism commonly present worldwide in the human population, sometimes causing serious illnesses such as duodenal and gastric ulcers, adenocarcinoma of the stomach, and low-grade B-cell mucosa-associated lymphoid tissue lymphoma of the stomach. This article describes a multiplex-touchdown PCR method for the identification and genotyping (vacA-s1/m1, sl/m2, and s2/m2-and cagA genes) of Hp directly from sheep milk artificially contaminated with Hp strains from human gastric biopsies and with Hp ATCC 43504. The strains from humans carried sl/m2 cagA+ and s2/m2 cagA allelic combinations, while the ATCC strains carried an sl/ml cagA+ allelic combination. The technique showed a sensitivity of 15 CFU/ml for species identification and of 1,500 CFU/ml for the detection of genes encoding for VacA and CagA. It has proven to be specific and rapid, and the authors suggest that it be used as a rapid screening method to ensure that sheep milk is uncontaminated with this organism.     

Retention behaviour of anti-emetic serotonin antagonists in reversed phase high performance liquid chromatography

Granisetron, Ondansetron and Tropisetron, three 5-HT3 antagonists showing anti-emetic activity, were analysed by HPLC on lipophilic stationary phases. The addition of an amine or quaternary ammonium salt to the eluents was a powerful tool in the analysis of these basic substances. The influence on chromatographic parameters of pH, ionic strength and various counter-ions in the aqueous phase as well as of different organic modifiers is discussed. Some of the proposed experimental conditions allow a more strictly partition-based separation mechanism and can produce chromatographic parameters suitable for structure-activity studies. These experimental conditions are also suitable for analysis of the considered compounds in pharmaceutical dosage forms or in biological fluids.