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The detection of oligoclonal IgG bands in cerebrospinal fluid (CSF) by isoelectricfocusing and immunodetection is the current "gold standard" method to detect an inflammatory process in central nervous system. However, as this test is time consuming and subjective, some authors have tested the measurement of free light chains (FLC) in CSF using a specific automated polyclonal antibody-based assay (Freelite, The Binding Site) with promising results. Recently, another automated nephelometric monoclonal antibody-based assay for FLC has been made available (N Latex FLC, Siemens). In our laboratories, we tested FLCκ and λ in CSF and serum using both assays. To test sensitivity and specificity, multiple sclerosis (MS) patients and non inflammatory neurological disease (NIND) patients as controls were selected. Both laboratories found statistically significant (P <0.05) difference between results in two groups. Using Freelite, the first laboratory defined the best cut-offs to discriminate between MS and NIND by ROC curves: i.e., 0.56 mg/L for FLCκ, 7.82 for FLCκ index, 0.31 mg/L for FLCλ and 4.36 for FLCλ index. Using N Latex FLC, the second laboratory estimated cut-offs by means of the NIND patients highest interquartile value, resulting in 0.22 mg/L for FLCκ, 2.72 for FLCκ index, 0.15 mg/L for FLCλ and 2.07 for FLCλ index. Sensitivities found with Freelite assay were 95% for FLCκ index, 83% for FLCλ index and 100% when both tests were considered. With N Latex FLC assay sensitivities were 100% for FLCκ index and 93% for FLCλ index. In both centers, isoelectricfocusing had 97% global sensitivity for MS. Our results show that, with both evaluated methods, CSF FLC can support or even replace isoelectricfocusing in clinical laboratories. Source

Trusso S.,CNR Institute for Chemical and Physical Processes | Zanchi C.,Polytechnic of Milan | Bombelli A.,Polytechnic of Milan | Lucotti A.,Polytechnic of Milan | And 5 more authors.
Journal of Instrumentation | Year: 2016

Au nanoparticle arrays with controlled nanostructure were produced by pulsed laser ablation on glass. Such substrates were optimized for biomedical sensing by means of SERS keeping fixed all process parameters but the laser pulse (LP) number that is a key deposition parameter. It allows to fine-tune the Au surface nanostructure with a considerable improvement in the SERS response towards the detection of apomorphine in blood serum (3.3 × 10-6 M), when LP number is increased from 1 × 104 to 2 × 104. This result is the starting point to correlate the intensity of selected SERS signals of apomorphine to its concentration in the blood of patients with Parkinson's disease. © 2016 IOP Publishing Ltd and Sissa Medialab srl. Source

Zanchi C.,Polytechnic of Milan | Lucotti A.,Polytechnic of Milan | Tommasini M.,Polytechnic of Milan | Trusso S.,CNR Institute for Chemical and Physical Processes | And 3 more authors.
Applied Surface Science | Year: 2016

By nanosecond pulsed laser ablation in an ambient gas gold nanoparticles (NPs) were produced that self-assemble on a substrate resulting in increasingly elaborated architectures of growing thickness, from isolated NP arrays up to percolated films. NPs nucleate and grow in the plasma plume propagating through the gas. Process parameters including laser wavelength, laser energy density, target to substrate distance, nature and pressure of the gas affect plasma expansion, thus asymptotic NP size and kinetic energy. NP size, energy and mobility at landing determine film growth and morphology that affect the physico-chemical properties of the film. Keeping fixed the other process parameters, we discuss the sensitive dependence of film surface nanostructure on Ar pressure and on laser pulse number. The initial plume velocity and average ablated mass per pulse allow predicting the asymptotic NP size. The control of growth parameters favors fine-tuning of NP aggregation, relevant to plasmonics to get optimized substrates for surface enhanced Raman spectroscopy (SERS). Their behavior is discussed for testing conditions of interest for clinical application. Both in aqueous and in biological solutions we obtained good sensitivity and reproducibility of the SERS signals for the anti-Parkinson drug apomorphine, and for the anti-epilepsy drug carbamazepine. © 2016 Elsevier B.V. Source

Bernardi G.,Laboratorio Of Patologia Clinica E Genetica Medica | Passerini G.,Diagnostica e Ricerca San Raffaele | Previtali G.,Presidio | Ciusani E.,Laboratorio Of Patologia Clinica E Genetica Medica
Biochimica Clinica | Year: 2014

Pathological CSF leakage outside central nervous system is a very dangerous situation with high risk of meningitis and cerebral abscess. Rhinorrhoea and post-surgical CSF leakage are the most frequent conditions. Diagnosis is made by combination of imaging procedures, radionucleide cisternography via lumbar puncture (fluorescein) and biochemical tests, which utilize markers suggesting the presence of CSF in suspected fluid. Low CSF glucose concentrations suggest rhinorrhoea, as glucose is absent in nose secretion, but cannot be used in post-surgical leakage, as blood is nearly almost present. CSF proteins are the best biomarkers and intrathecal synthesized β-trace protein and transferrin are the best choice. For quantitative analysis, nephelometric β-trace protein measurement has the best performance, as it can be easily automatically performed, also for stat analysis, but relatively high volume of sample is needed. Isoelectricfocusing or high resolution electrophoresis followed by immunodetection are the most sensitive and specific methods for detecting asialotransferrin, but they are time consuming, unsuitable for stat analysis, even if they need low amounts of sample. Other quantitative tests include prealbumin/albumin ratio, having insufficient sensitivity in blood contaminated samples, and zone electrophoresis of protein pattern that, however, has too low sensitivity. New methods like capillary electrophoresis have been recently proposed. Source

Bernardi G.,Laboratorio Of Patologia Clinica E Genetica Medica | Brunati P.,Laboratorio Analisi Chimico Cliniche e Microbiologia | Biagioli T.,Laboratorio Generale | Buoro S.,Laboratorio Analisi Chimico Cliniche | And 8 more authors.
Biochimica Clinica | Year: 2014

The laboratory investigation of CSF has been developed over the years as a diagnostic tool for many neurological diseases. Although minimally invasive, CSF is obtained with a traumatic procedure; therefore, the whole laboratory process should be established to maximize the analytical performance. Based on the review of international guidelines and on the experience developed by members of the SIBioC Working Group, the present document provides practical information for laboratory professionals to better address the CSF analysis in different diagnostic situations. The report faces the pathophysiologic meaning of the determination of biochemical parameters, such as glucose, lactate, albumin, immunoglobulins, β-amyloid, tau protein, and the cellular content, providing also evidence on the proper methodological approach. Quantitative and qualitative CSF parameters useful to diagnose an inflammatory process of the central nervous system are discussed, particularly with reference to multiple sclerosis. Indications on how laboratory data should be presented to meet international recommendations are also included. Source

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