Gaelle Tachon

Transport of the fluorescent organic cation 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP+) in human respiratory epithelial cells

Organic cation/carnitine transporters (OCT/N) mediate uptake of positively charged molecules. Their role in lung epithelium; however, is not well understood. OCT/N expression and activity was studied in cell lines of human alveolar (A549), bronchial (16HBE14o- and Calu-3) and intestinal (Caco-2) epithelium. Protein levels were largely comparable for all OCT/Ns in the respiratory epithelial cell lines studied; however, OCT2 was exclusively observed in A549 cells. OCT1 and -2 were present at significantly higher levels in Caco-2 cells, compared with the pulmonary epithelial cell types. OCTN1 and -2 were also more abundant in Caco-2. Only OCT3 was expressed evenly across all cell lines investigated. Uptake of 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP(+)) was dependent on concentration, temperature, membrane potential and pH. In 16HBE14o-, Calu-3 and Caco-2 monolayers, substrate saturation of ASP(+) uptake was not reached. Alveolar A549 cells showed saturable ASP(+) uptake via two transporter sites with K(m) values of 12.5 ± 4.0 μM and 456.9 ± 164.5 μM, respectively. This uptake was sensitive to organic cations, but insensitive to carnitine and lysine. We conclude that uptake of organic cations is facilitated by distinct pathways in different regions of lung mucosa. Luminally localised OCT2 appears to be exclusively involved in the alveolar epithelium, whereas basolateral localised OCT3 might play a role in alveolar as well as in bronchial epithelial cells.

The role of genetic factors in patients with hepatocellular carcinoma and iron overload - a prospective series of 234 patients.

Iron overload (IO) in HFE‐related hereditary haemochromatosis is associated with increased risk of liver cancer. This study aimed to investigate the role of other genes involved in hereditary IO among patients with hepatocellular carcinoma (HCC).

Cardiovascular risk stratification in hemodialysis patients in the era of highly sensitive troponins: should we choose between hs-troponin I and hs-troponin T?

Abstract Background: New highly sensitive (hs) assays have challenged the interpretation of cardiac troponins (cTn). The present study was designed to evaluate simultaneously conventional cTnT and cTnI together with their corresponding highly sensitive determinations in stable hemodialysis (HD) patients. Ability of cTn to stratify HD patient risk was assessed. Methods: A total of 224 stable HD patients was included in this observational study. cTnT and hs-cTnT were measured using Roche cTnT/hs-cTnT assays based on a Cobas e601® analyzer. cTnI and hs-cTnI were measured using Beckman AccuTnI/hs-TnI IUO assays on Access II system. Patients were followed up prospectively during 9 years. Relationship between cTn level and mortality was assessed through Cox survival analysis. Results: The median cTnT and cTnI concentrations were 38.5 ng/L (IQR, 18.8–76) and 10 ng/L (IQR, 10–20), respectively. The median hs-cTnT and hs-cTnI concentrations were 62.5 ng/L (IQR, 38.8–96.3) and 13.9 ng/L (IQR, 8.4–23.6), respectively. The prevalence of values above the 99th percentile was significantly more marked with cTnT (85.3 and 97.8% for conventional and hs cTnT, respectively) than with cTnI (7.6 and 67.4% for conventional and hs cTnI, respectively). During the follow-up, 167 patients died, mainly from cardiac cause (n=77). The optimized cut-off values, determined by bootstrap method, predicting mortality were 38, 69, 20 and 11 ng/L for cTnT, hs-cTnT, cTnI and hs-cTnI, respectively. After full adjustment, elevated plasma concentrations of all troponin were significant predictors of mortality. Conclusions: A large proportion of patients free of acute coronary syndrome (ACS) has hs-cTn I or T higher than the 99th percentile which could be seen as a limiting factor for ACS screening. However, all generation and type of troponin assays could be reliable indicators of prognosis risk in HD patients.

Discordant sex in monozygotic XXY/XX twins: a case report

We report a case of discordant phenotypic sex in monozygotic twins mosaic 47,XXY/46,XX: monozygotic heterokaryotypic twins. The twins presented with cognitive and comprehension delay, behavioural and language disorders, all symptoms frequently reported in Klinefelter syndrome. Molecular zygosity analysis with several markers confirmed that the twins are in effect monozygotic (MZ). Array comparative genomic hybridization found no evidence for the implication of copy number variation in the phenotypes. Ultrasound scans of the reproductive organs revealed no abnormalities. Endocrine tests showed a low testosterone level in Twin 1 (male phenotype) and a low gonadotrophin level in Twin 2 (female phenotype) which, combined with the results from ultrasound examination, provided useful information for potentially predicting the future fertility potential of the twins. Blood karyotypes revealed the presence of a normal 46,XX cell line and an aneuploïd 47,XXY cell line in both patients. Examination of the chromosome constitutions of various tissues such as blood, buccal smear and urinary sediment not surprisingly showed different proportions for the 46,XX and 47,XXY cell lines, which most likely explains the discordant phenotypic sex and mild Klinefelter features. The most plausible underlying biological mechanism is a post-zygotic loss of the Y chromosome in an initially 47,XXY zygote. This would result in an embryo with both 46,XX and 47,XXY cells lines which could subsequently divide into two monozygotic embryos through a twinning process. The two cell lines would then be distributed differently between tissues which could result in phenotypic discordances in the twins. These observations emphasize the importance of regular paediatric evaluations to determine the optimal timing for fertility preservation measures and to detect new Klinefelter features which could appear throughout childhood in the two subjects.

Variants du facteur VII de la coagulation : quelle thromboplastine utiliser pour doser son activité ?

Le deficit constitutionnel en facteur VII de la coagulation (FVII), caracterise par une grande heterogeneite clinique et biologique, a pour particularite de presenter des variants FVII dont le dosage de l’activite (FVII:C) varie selon la thromboplastine utilisee. Il s’agit en particulier des variants p.Arg364Gln et p.Arg139Gln, tres frequents sur le continent africain et dans le sud de l’Europe, mais la liste de ces variants s’allonge avec la caracterisation moleculaire des deficits en FVII. Les hypotheses physiopathologiques reposent sur la difference de la sequence proteique des facteurs tissulaires humains ou de lapin composant les thromboplastines. L’analyse des phenotypes cliniques associes conforte l’option consistant a retenir la valeur obtenue avec une thromboplastine humaine, c’est-a-dire composee du facteur tissulaire physiologique. Il est ainsi recommande de controler toute valeur de FVII:C dans le cadre d’un deficit constitutionnel en FVII afin de ne pas surtraiter ces patients.

A Haut-Doubs FVII variant depending on species-derived- thromboplastin reagent (F7:p.Arg337His)

*Laboratoire d’hemostase Etablissement Franc ais du Sang, Besanc on; †Departement d’hematologie biologique CHU deMontpellier, Hopital Saint Eloi, Montpellier;^ ‡CEA, iBEB Service de Biochimie et Toxicologie Nucleaire, Bagnols sur Ceze;§Laboratoire d’Hematologie Centre de Biologie et Pathologie EA-2693, Centre Hospitalier Regional et Universitaire, Lille;¶Centre Regional de Traitement de l’Hemophilie, Laboratoire hematologie, CHU Hotel-Dieu, Nantes; and^ kCentre Regionalde Traitement de l’Hemophilie, Service d’hematologie CHU Besanc on, Besanc on, France