Towards harmonization of solutions used for cystic fibrosis diagnosis by nasal potential difference measurements: A formulation approach with CHESS® software.

BACKGROUND: One diagnosis of cystic fibrosis involves measuring the nasal transepithelial potential difference (NPD) as a complementary technique in the forms of the disease, where the sweat test is non-discriminating. The NPD is measured using solutions with and without chlorides, containing a variety of substances whose activities on nasal mucus membranes are studied or assessed. Among the solutions described in the literature and used in specialized centers, none seems to be best adapted for industrial production for reasons of stability (formulas of the international consensus of Rowe et al. and formulas of Knowles et al.) and/or potential toxicity (formulas of Middleton et al.). OBJECTIVE(S): Defining new formulas, according to those of the international consensus, with greater physicochemical and microbiological stability. METHODS: The reformulation tests were conducted on the formulas of Rowe et al., using CHESS® (CHemical Equilibrium of Species and Surfaces) software for modeling aqueous systems that substantially reduced the number of experiments. CHESS® software was first validated using models of ideal and non-ideal solutions. Thereafter, experimentation was carried out for the sake of comparison with theoretical data. RESULTS: CHESS® software using models of ideal and non-ideal solutions were validated. The experimentation confirmed the theoretical data, and new formulas were assessed based on their physicochemical (pH, content, Osmolality) and microbiological stability. CONCLUSION: The new formulas defined here guarantee excellent physicochemical and microbiological stability of diagnostic solutions, indispensable criteria for harmonizing and comparing results from different specialized centers using NPD measurements. These new formulas apply to the harmonization approach of techniques for measuring the nasal transepithelial potential difference.

Imatinib: Major photocatalytic degradation pathways in aqueous media and the relative toxicity of its transformation products.

Imatinib (IMA) is a highly potent tyrosine kinase inhibitor used as first-line anti-cancer drug in the treatment of chronic myeloid leukemia. Due to its universal mechanism of action, IMA also has endocrine and mutagenic disrupting effects in vivo and in vitro, which raises the question of its environmental impact. However, to date, very little information is available on its environmental fate and the potential role of its transformation products (TPs) on aquatic organisms. Given the IMA resistance to hydrolysis and direct photolysis according to the literature, we sought to generate TPs through oxidative and radical conditions using the AOPs pathway. Thus, the reactivity of the cytotoxic drug IMA in water in the presence of OH and h+ was investigated for the first time in the present work. In this regard, a non-targeted screening approach was applied in order to reveal its potential TPs. The tentative structural elucidation of the detected TPs was performed by LC-HRMSn. The proposed approach allowed detecting a total of twelve TPs, among which eleven are being described for the first time in this work. Although the structures of these TPs could not be positively confirmed due to lack of standards, their chemical formulas and product ions can be added to databases, which will allow their screening in future monitoring studies. Using the quantitative structure-activity relationship (QSAR) approach and rule-based software, we have shown that the detected TPs possess, like their parent molecule, comparable acute toxicity as well as mutagenic and estrogenic potential. In addition to the in silico studies, we also found that the samples obtained at different exposure times to oxidative conditions, including those where IMA is no longer detected, retained toxicity in vitro. Such results suggest further studies are needed to increase our knowledge of the impact of imatinib on the environment.

Guanosine diphosphate-mannose:GlcNAc2-PP-dolichol mannosyltransferase deficiency (congenital disorders of glycosylation type Ik): five new patients and seven novel mutations.

BACKGROUND: In type I congenital disorders of glycosylation (CDG I), proteins necessary for the biosynthesis of the lipid-linked oligosaccharide (LLO) required for protein N-glycosylation are defective. A deficiency in guanosine diphosphate-mannose: GlcNAc(2)-PP-dolichol mannosyltransferase-1 (MT-1) causes CDG Ik (OMIM 608540), and only five patients, with severe multisystemic clinical presentations, have been described with this disease. Objective To characterise genetic, biochemical and clinical data in five new CDG Ik cases and compare these findings with those of the five previously described patients. Methods LLO biosynthesis was examined in skin biopsy fibroblasts, mannosyltransferases were assayed in microsomes prepared from these cells, and ALG1-encoding MT-1 was sequenced at the DNA and complementary DNA levels. Clinical data for the five new patients were collated. RESULTS: Cells from five patients with non-typed CDG I revealed accumulations of GlcNAc(2)-PP-dolichol, the second intermediate in the biosynthesis of LLO. Assay of MT-1, -2 and -3, the first three mannosyltransferases required for extension of this intermediate, demonstrated only MT-1 to be deficient. DNA sequencing of ALG1 revealed nine different mutations, seven of which have not been previously reported. Clinical presentations are severe, with dysmorphias, CNS involvement and ocular disturbances being prevalent. CONCLUSIONS: 5 patients with CDG Ik are described, and their identification reveals that in France, this disease and CDG Ib (mannose phosphate isomerase deficiency: OMIM 602579) are the most frequently diagnosed CDG I after CDG Ia (phosphomannomutase 2 deficiency: OMIM 601785) and substantiate previous observations indicating that this disease presents at the severe end of the CDG I clinical spectrum.