Éditeur(s) : Elsevier
Résumé : The family Kareniaceae is mostly known in France for recurrent blooms of Karenia mikimotoi in the Atlantic, English Channel, and Mediterranean Sea and for the unusual green discoloration in the saltwater lagoon of Diana (Corsica) caused by Karlodinium corsicum in April 1994. In terms of diversity, this taxonomic group was long overlooked owing to the difficult identification of these small unarmored dinoflagellates. In this study, thanks to the molecular characterization performed on single cells from field samples and cultures, twelve taxonomic units were assigned to the known genera Karenia, Karlodinium and Takayama, whereas one could not be affiliated to any described genus. The molecular phylogeny inferred from the D1–D2 region of the LSU rDNA showed that five of them formed a sister taxon of a known species, and could not be identified at species-level, on the basis of molecular analysis only. Among these latter taxa, one Karlodinium which was successfully cultured was investigated by studying the external morphological features (using two procedures for cells fixation), ultrastructure, pigment composition, and haemolytic activity. The results of our analyses corroborate the genetic results in favour of the erection of Karlodinium gentienii sp. nov., which possesses an internal complex system of trichocysts connected to external micro-processes particularly abundant in the epicone, and a peculiar pigment composition. In addition, preliminary assays showed a haemolytic activity.
Harmful Algae (1568-9883) (Elsevier), 2014-12 , Vol. 40 , P. 75-91

Droits : 2014 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00225/33611/32310.pdf
DOI:10.1016/j.hal.2014.10.006
http://archimer.ifremer.fr/doc/00225/33611/

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Oxidative stress and haemolysis-associated nitric oxide (NO) depletion plays a crucial role in the development of vasculopathy in sickle cell anaemia (SS). However it remains unknown whether oxidative stress and haemolysis levels influence vascular function in patients with sickle haemoglobin C disease (SC). Microvascular response to heat (using Laser Doppler flowmetry on finger), oxidative stress biomarkers, NO metabolites, endothelin-1 and haematological parameters were compared between patients with SS and SC. Vascular function, oxidative and nitrosative markers were also measured in healthy (AA) children. SS and SC had increased plasma advanced oxidation protein products (AOPP), malondialdehyde, plasma antioxidant activities and NO end products, compared to AA. SC had lower catalase activity compared to AA and SS. Haemolytic rate, glutathione peroxidase and nitrotyrosine concentrations were significantly increased in children with SS compared to SC and AA. SS and SC had impaired microvascular reactivity compared to AA. In SS, the plateau phase of the response to local thermal heating was negatively associated with nitrotyrosine and AOPP. No association between vascular function parameters and oxidative stress markers was observed in SC. Mild haemolysis in SC, compared to SS, may limit oxidative and nitrosative stress and could explain the better preserved microvascular function in this group.
ISSN: 0007-1048

hal-01668314
https://hal.univ-antilles.fr/hal-01668314
DOI : 10.1111/bjh.14693

Éditeur(s) : HAL CCSD
Résumé : International audience
Reports on dengue morbidity in patients with sickle cell disease (SCD) are scarce. Dengue is arthropod-borne viroses due to dengue virus (DENV) and affects populations with a high prevalence of SCD; therefore, the risk of morbidity may be increased.To determine the impact of dengue infection in SCD patients, we reviewed medical records during a vast outbreak of dengue virus serotype-2 (DENV-2) in French Guiana in 2012-2013. We identified 10 cases of laboratory-confirmed dengue infection;these were classified into A, B and C categories based on levels of severity of dengue according to World Health Organisation (WHO). The average age of SCD patients was 18.2 years. 1, 6 and 3 cases were classified as A, B and C WHO severity criteria, respectively. All patients had an important decrease in haematocrit (while one of the WHO severity criteria is the increase of haematocrit). Only one patient had decreased platelet count. Seven cases had vaso-occlusive crisis (VOC), six patients developed acute hepatitis and eight had a simultaneous bacterial infection. Six of them needed a blood transfusion. The results suggested that the WHO severity laboratory criteria of hemoconcentration and platelet counts were not helpful in themanagement of SCD patients. The morbidity was mainly caused by specific complications of SCD, especially VOC, likely facilitated by vascular endothelial damages consecutive to dengue fever, severe haemolysis, hepatitis and bacterial co-infections.
Journal of Virology and Retrovirology

Droits : info:eu-repo/semantics/OpenAccess
inserm-01419456
http://www.hal.inserm.fr/inserm-01419456
http://www.hal.inserm.fr/inserm-01419456/document
http://www.hal.inserm.fr/inserm-01419456/file/2015%2C%20Mosnier%20-%20Dengue%20infection%20in%20sickle%20cell%20patients%20in%20French%20Guiana.pdf

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Hydroxycarbamide (HC) treatment has been shown to improve the clinical course of patients with sickle cell anaemia (SCA), a haemoglobinopathy resulting from a single base substitution in the bêta-globin gene (HBB). SCA is characterized by chronic haemolytic anaemia and recurrent vascular occlusions leading to multisystemic complications. Several beneficial biological effects of HC have been documented (Halsey et al, 2003) but its impact on the concentration of circulating microparticles (MPs), a subtype of extracellular vesicles released from cytoplasmic membrane of activated or apoptotic cells and detected at high levels in sickle plasma, remains controversial (Hebbel et al, 2016). The aim of the present study was to compare the MP pattern in a group of SCA patients treated by HC and followed for 2 years.
ISSN: 0007-1048

hal-01668320
https://hal.univ-antilles.fr/hal-01668320
https://hal.univ-antilles.fr/hal-01668320/document
https://hal.univ-antilles.fr/hal-01668320/file/Garnier%20et%20al%20BJH-2017-00655.pdf
DOI : 10.1111/bjh.14810