Validation of an isotope dilution mass spectrometry (IDMS) measurement procedure for the reliable quantification of steroid hormones in waters.

Reliable data are compulsory to efficiently monitor pollutants in aquatic environments, particularly steroid hormones that can exert harmful effects at challenging analytical levels below the ng L. An isotope dilution two-step solid-phase extraction followed by an ultra-performance liquid chromatography separation coupled to tandem mass spectrometry (UPLC-MS/MS) detection method was validated for the quantification of 21 steroid hormones (androgens, estrogens, glucocorticoids, and progestogens) in whole waters. To achieve a realistic and robust assessment of the performances of this method, the validation procedure was conducted using several water samples representative of its intended application.

Development of a candidate reference measurement procedure by ID-LC-MS/MS for total tau protein measurement in cerebrospinal fluid (CSF).

Objectives: In clinical pratice, tau protein measurement generally relies on immunoassays (IAs), whose major drawback is the lack of results comparability due to differences in selectivity and/or calibration. This underlines the importance of establishing a traceability chain for total tau (t-tau) measurements. The objective of this work is to develop a higher order candidate reference measurement procedure (RMP) for the absolute quantification of t-tau in cerebrospinal fluid (CSF).

Candidate High-Resolution Mass Spectrometry-Based Reference Method for the Quantification of Procalcitonin in Human Serum Using a Characterized Recombinant Protein as a Primary Calibrator.

Procalcitonin (PCT) is a widely used biomarker for rapid sepsis diagnosis and antibiotic stewardship. Variability of results in commercial assays has highlighted the need for standardization of PCT measurements. An antibody-free candidate reference measurement procedure (RMP) based on the isotope dilution mass spectrometry and protein calibration approach was developed and validated to quantify PCT in human serum.

Overcoming matrix effects in quantitative liquid chromatography-mass spectrometry analysis of steroid hormones in surface waters.

Rationale: Accurate and reliable measurements are mandatory in the field of environmental monitoring. Matrix effects are often depicted as the Achilles' heel of liquid chromatography-mass spectrometry analysis since they may be prejudicial for analytical performances such as detection capability and accuracy, if not documented or compensated. Here a methodology for the evaluation and compensation of matrix effects is described.

Harmonization status of procalcitonin measurements: what do comparison studies and EQA schemes tell us?

Sepsis represents a global health priority because of its high mortality and morbidity. The key to improving prognosis remains an early diagnosis to initiate appropriate antibiotic treatment. Procalcitonin (PCT) is a recognized biomarker for the early indication of bacterial infections and a valuable tool to guide and individualize antibiotic treatment.

Development of an antibody-free ID-LC MS method for the quantification of procalcitonin in human serum at sub-microgram per liter level using a peptide-based calibration.

The quantification of low abundant proteins in complex matrices by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) remains challenging. A measurement procedure based on optimized antibody-free sample preparation and isotope dilution coupled to LC-MS/MS was developed to quantify procalcitonin (PCT) in human serum at sub-microgram per liter level. A combination of sodium deoxycholate-assisted protein precipitation with acetonitrile, solid-phase extraction, and trypsin digestion assisted with Tween-20 enhanced the method sensitivity.

Evaluation of the necessity and the feasibility of the standardization of procalcitonin measurements: Activities of IFCC WG-PCT with involvement of all stakeholders.

Procalcitonin (PCT) is an important biomarker for sepsis diagnosis and management. To date, there is no higher-order reference measurement procedure (RMP) and certified reference material to achieve global standardization of results and results traceability to the SI units. Although efforts have been made to harmonize PCT results, a number of comparison studies and external quality assessment (EQA) schemes show conflicting results regarding results comparability and to date, equivalence of PCT results across the assays remains questionable in absence of studies relying on commutable EQA materials.

Dissociating effect of salivary gland extract from Ixodes ricinus on human fibroblasts: Potential impact on Borrelia transmission.

Understanding the mechanism of pathogen transmission is essential for the development of strategies to reduce arthropod-borne diseases. The pharmaco- and immunomodulatory properties of insect and acarine saliva play an essential role in the efficiency of pathogen transmission. The skin as the site where arthropod saliva and pathogens are inoculated - represents the key interface in vector-borne diseases.

Heterogeneity of Borrelia burgdorferi Sensu Stricto Population and Its Involvement in Borrelia Pathogenicity: Study on Murine Model with Specific Emphasis on the Skin Interface.

Lyme disease is a multisystemic disorder caused by B. burgdorferi sl. The molecular basis for specific organ involvement is poorly understood.

Discovery and targeted proteomics on cutaneous biopsies infected by borrelia to investigate lyme disease.

Lyme disease is the most important vector-borne disease in the Northern hemisphere and represents a major public health challenge with insufficient means of reliable diagnosis. Skin is rarely investigated in proteomics but constitutes in the case of Lyme disease the key interface where the pathogens can enter, persist, and multiply. Therefore, we investigated proteomics on skin samples to detect Borrelia proteins directly in cutaneous biopsies in a robust and specific way.

Proteomic analysis of three Borrelia burgdorferi sensu lato native species and disseminating clones: relevance for Lyme vaccine design.

Lyme borreliosis is the most important vector-borne disease in the Northern hemisphere. It is caused by Borrelia burgdorferi sensu lato bacteria transmitted to humans by the bite of hard ticks, Ixodes spp. Although antibiotic treatments are efficient in the early stage of the infection, a significant number of patients develop disseminated manifestations (articular, neurological, and cutaneous) due to unnoticed or absence of erythema migrans, or to inappropriate treatment.

Innovative native MS methodologies for antibody drug conjugate characterization: High resolution native MS and IM-MS for average DAR and DAR distribution assessment.

Antibody drug conjugates (ADCs) are macromolecules composed of cytotoxic drugs covalently attached via a conditionally stable linker to monoclonal antibodies (mAbs). ADCs are among the most promising next generation of empowered mAbs foreseen to treat cancers. Compared to naked mAbs, ADCs have an increased level of complexity as the heterogeneity of conjugation cumulates with the inherent microvariability of the biomolecule.

Effects of controlled ingestion of kaolinite (5%) on food intake, gut morphology and in vitro motility in rats.

Geophagia is found in various animal species and in humans. We have previously shown that spontaneously ingested kaolinite interacts with the intestinal mucosa modifies nutrient absorption and slows down gastric emptying and intestinal transit in rats in vivo. However, the precise mechanisms involved are not elucidated.