Cis-regulatory evolution spotlights species differences in the adaptive potential of gene expression plasticity.

Phenotypic plasticity is the variation in phenotype that a single genotype can produce in different environments and, as such, is an important component of individual fitness. However, whether the effect of new mutations, and hence evolution, depends on the direction of plasticity remains controversial. Here, we identify the cis-acting modifications that have reshaped gene expression in response to dehydration stress in three Arabidopsis species. Our study shows that the direction of effects of most cis-regulatory variants differentiating the response between A. thaliana and the sister species A. lyrata and A. halleri depends on the direction of pre-existing plasticity in gene expression. A comparison of the rate of cis-acting variant accumulation in each lineage indicates that the selective forces driving adaptive evolution in gene expression favors regulatory changes that magnify the stress response in A. lyrata. The evolutionary constraints measured on the amino-acid sequence of these genes support this interpretation. In contrast, regulatory changes that mitigate the plastic response to stress evolved more frequently in A. halleri. Our results demonstrate that pre-existing plasticity may be a stepping stone for adaptation, but its selective remodeling differs between lineages.

Actin modulates shape and mechanics of tubular membranes.

The actin cytoskeleton shapes cells and also organizes internal membranous compartments. In particular, it interacts with membranes for intracellular transport of material in mammalian cells, yeast, or plant cells. Tubular membrane intermediates, pulled along microtubule tracks, are formed during this process and destabilize into vesicles. While the role of actin in tubule destabilization through scission is suggested, literature also provides examples of actin-mediated stabilization of membranous structures. To directly address this apparent contradiction, we mimic the geometry of tubular intermediates with preformed membrane tubes. The growth of an actin sleeve at the tube surface is monitored spatiotemporally. Depending on network cohesiveness, actin is able to entirely stabilize or locally maintain membrane tubes under pulling. On a single tube, thicker portions correlate with the presence of actin. These structures relax over several minutes and may provide enough time and curvature geometries for other proteins to act on tube stability.

Arabidopsis species deploy distinct strategies to cope with drought stress.

BACKGROUND AND AIMS: Water limitation is an important determinant of the distribution, abundance and diversity of plant species. Yet, little is known about how the response to limiting water supply changes among closely related plant species with distinct ecological preferences. Comparison of the model annual species Arabidopsis thaliana with its close perennial relatives A. lyrata and A. halleri, can help disentangle the molecular and physiological changes contributing to tolerance and avoidance mechanisms, because these species must maintain tolerance and avoidance mechanisms to increase long-term survival, but they are exposed to different levels of water stress and competition in their natural habitat. METHODS: A dry-down experiment was conducted to mimic a period of missing precipitation. The covariation of a progressive decrease in soil water content (SWC) with various physiological and morphological plant traits across a set of representative genotypes in A. thaliana, A. lyrata and A. halleri was quantified. Transcriptome changes to soil dry-down were further monitored. KEY RESULTS: The analysis of trait covariation demonstrates that the three species differ in the strategies they deploy to respond to drought stress. Arabidopsis thaliana showed a drought avoidance reaction but failed to survive wilting. Arabidopsis lyrata efficiently combined avoidance and tolerance mechanisms. In contrast, A. halleri showed some degree of tolerance to wilting but it did not seem to protect itself from the stress imposed by drought. Transcriptome data collected just before plant wilting and after recovery corroborated the phenotypic analysis, with A. lyrata and A. halleri showing a stronger activation of recovery- and stress-related genes, respectively. CONCLUSIONS: The response of the three Arabidopsis species to soil dry-down reveals that they have evolved distinct strategies to face drought stress. These strategic differences are in agreement with the distinct ecological priorities of the stress-tolerant A. lyrata, the competitive A. halleri and the ruderal A. thaliana.

[Difficulty in diagnosis of a cardiogenic shock with thrombotic and sub-occluded LAD. A train can hide another one!] / Difficulté diagnostic d'un choc cardiogénique sur une sub-occlusion thrombotique de l'IVA. Un train peut en cacher un autre !

The pheochromocytome is a localized tumor at the level of the medullosurrenale in 85% of the cases. The clinical presentation is very variable. Severe Heart failure presentation can be the mode of revelation in 2% of the cases. We present the case of a patient admitted for refractory cardiogenic shock correlated to pheochromocytome tumor. The difficulty of this rare clinical presentation was to confirm rapidly and in emergency this diagnosis in the same time when the patient presents a persistante and severe cardiogenic chock after finding a sub-occluded and thrombotic LAD coronary artery and which was treated by thrombectomy and coronary revascularization. The surgical treatment of this tumor is considered to be a quickly saving treatment. It allows a fast recovery of the cardiac function.

[Coronary ectasias and thrombosis]. / Ectasies coronaires et thrombus.

Ectasias and coronary aneurysms are uncommon coronary artery diseases, can coexist and are poorly known. Their principal etiology in adults is coronary atherosclerosis. It has been suggested that these abnormalities would have poor prognosis and that slow flow could lead to in situ thrombosis and distal embolisation. However, ectasias and aneurysms are most often associated with coronary stenosis. We report a series of 47 cases of ectasias and coronary aneurysms with evaluation of the clinical and angiographic characteristics, the therapeutic choices and we review the literature concerning these lesions. In situ thrombosis does not seem to be the usual pathophysiological mechanism. We retain that this is a particular form of coronary atherosclerosis in this population and present technical problems in case of revascularization with an predominant indication of medical treatment (57.4 % of the cases), but rarely the introduction of anticoagulants (4.25 % of the cases), except in acute coronary syndromes where revascularization is most common (70.6 % of cases) as is usually expected in the general population. The complex angiographic presentation of these lesions is probably an explanation for the low numbers of revascularizations performed.

[Ischemic stroke related to spontaneous]. / Accident vasculaire cérébral ischémique en rapport avec hématome coronaire spontané.

Cardiovascular disease in women is a particularly complex pathology especially in the youngest population. The clinical presentation of acute coronary syndromes is sometimes misleading and does not necessarily point to the potential presence of cardiac disease given the frequent absence of cardiovascular risks. Such complexity results in delayed diagnosis, which worsens the outcome of myocardial infarction and generates complications related to the absence of coronary revascularization. We report the case of a patient who suffered an (undiagnosed) apical myocardial infarction that went undetected and was complicated by a voluminous intraventricular thrombus with embolus migration in the cerebral circulation resulting in an ischemic accident. The combination of these two pathologies make their therapeutic management particularly difficult. As widely reported in the literature, the outcome of myocardial infarction in women is poorer than in their male counterparts for a number of reasons. We can assume that in the youngest patients, another physiopathological mechanism is often involved, namely, the occurrence of hematoma and spontaneous coronary dissection. Diagnosis is often difficult even with coronary angiography diagnosis. As shown in the case reported here, initial examination results, if not thoroughly analyzed, may be erroneously interpreted as normal. It is also likely that the presence of hematoma or coronary wall dissection without any plaque rupture may negatively influence the outcome owing to the implementation of inappropriate treatments. In conclusion, in patients presenting with an ischemic cerebral accident, meticulous cardiac examination must be performed even in young women with no cardiovascular risk factors given that the occurrence of hematoma or coronary dissection may contribute to the formation of mural thrombi in the setting of myocardial infarction. Cardiac MRI seems to be particularly effective in the diagnosis of myocardial infarction complicated by the presence of intracavitary thrombi.

[Is coronary artery spasm a disease specific to women?] / Spasme coronaire, une pathologie de la femme ?

Vasospastic angina is considered rare in Europe but with a prevalence probably underestimated and affects preferentially men in published studies, mostly involving Asian populations. Vasospastic angina in the female population have specificities in terms of pathophysiology, clinical presentation and prognosis, as well as diagnostic strategies currently recommended, that we describe from a clinical case. Although known for over 50years, vasospastic angina remains a disease still insufficiently researched, probably even less in women. This form of angina must not however be forgotten, and the appropriate diagnostic strategy must be known and used to improve prognosis.

[Transfemoral TAVI procedure in women: Minimally-invasive technique]. / Procédure de TAVI par voie fémorale chez la femme : technique minimaliste.

Demographic data point to a substantial proportion of women in the population of elderly patients with an increasing prevalence of aortic stenosis. Implantation of an aortic bioprosthesis via an endovascular approach known as Transcatheter aortic valve implantation (TAVI) in patients presenting with a symptomatic tight aortic stenosis (severe aortic stenosis) (AS) is an alternative therapeutic option to surgical aortic valve replacement in patients at high surgical risk or ineligible for surgery. The literature has shown that this technique seems to be particularly beneficial in female patients. In the Partner A trial, the 1-year mortality rate was significantly lower in women compared to their male counterparts. Other data revealed that although women have a higher risk of experiencing periprocedural complications (vascular events, bleeding and stroke), their outcome is good and often better than that of men. These results are continuously improving thanks to the enhancement of techniques and devices. In view of the published reports reflecting the increasing experience of the teams, it clearly appears that the simplification of TAVI procedures has resulted in improved outcomes. We report here the case of a patient treated by means of a "minimalist" approach to TAVI allowing a reduction of the risks inherent in the procedure. This simplified strategy relies on an optimal use of CT scan findings prior to TAVI. The procedure is carried out under local anesthesia and the main access site is sutured percutaneously (Proglides). The radial artery is used as a secondary access site. Contrast medium is diluted and stimulation is administered via the intraventricular guidewire. Direct stenting is performed when deemed feasible on the basis of CT scan results. Simplified procedures such as these contribute to the improvement of TAVI outcomes. However, further studies focusing on female patients are warranted in order to corroborate these findings.

Use of electrical devices reveals our well being.

We want to objectivize the level of activity of elderly persons living independently at home. Most existing monitoring systems are intrusive and/or require a large number of sensors. We hope the "ubiquitous computing" concept could find an application in this context. We proposed to monitor the use of electrical appliances. We built a unique "activity indicator" which integrates all the activities of the person. This was assessed during 6 months within 12 flats occupied by single elderly persons.

Occurrence of Culicoides spp. (Diptera: Ceratopogonidae) in Tunisia, with emphasis on the bluetongue vector Culicoides imicola.

Following the bluetongue (BT) outbreaks in Tunisia from 1999 to 2002, BTV (bluetongue virus) serotype 2 was isolated; however, no entomological investigation was performed. In the study presented here, we assessed the Culicoides species populations (particularly C. imicola) in proximity to the BT outbreaks locations, both as a retrospective analysis and to update the list of Culicoides species present in Tunisia. The insects were caught using light traps and the species identification was performed according to the standard entomological methods. This study reveaaled the presence of significant numbers of C. imicola in all the tested locations. In addition, we reported a new Culicoides species for the Tunisian fauna C. punctatus.

Different distribution of H1-H2 Epstein-Barr virus variant in oropharyngeal virus and in biopsies of Hodgkin's disease and in nasopharyngeal carcinoma from Algeria.

In a previous study of Epstein-Barr virus (EBV) strains in North African nasopharyngeal carcinoma (N PC) biopsies, we have found that the viral strain present was of A/F/W'-I'/Xhol kept/H1-H2 type, while the strain associated with Chinese NPC was the A/"f"/W'I'/Xhol lost/H type. Using the restriction fragment length polymorphism (RFLP) and PCR-RFLP methods, the present study analyzed the H1-H2 variant in different clinical samples from Algeria, including the saliva of healthy EBV-positive individuals and patients with NPC or Hodgkin's disease (HD), as well as HD biopsies and lymphoblastoid cell lines (LCLs) established from the oropharyngeal virus-infected cells. Our results demonstrate that, in contrast to the H1-H2 variant found in NPC biopsies, the H genotype was dominant in HD biopsies. Moreover, H genotype was also dominant in the oropharynx of healthy EBV-positive individuals, of patients with NPC and with HD. Our results clearly indicate that in North Africa the EBV strain present of NPC biopsies is different from that shed in the oropharynx. This may suggest a specific distribution of the H1-H2 variant in the NPC epithelial tumor, whereas the H genotype is dominant in HD biopsies and in the oropharynx. The specific association of both viral strains with these 2 distinct diseases in North Africa may reflect a difference in tumorigenicity.

Epstein-Barr virus genotypes in NPC biopsies from north Africa.

The genotypes of Epstein-Barr virus (EBV) were investigated in North African nasopharyngeal carcinoma (NPC) biopsies, nasopharyngeal chronic inflammation (NCI) biopsies, and saliva of healthy individuals from Algeria and Tunisia where there is an intermediate incidence of NPC. The prevalence of A-type virus in NPC, NCI biopsies and saliva of healthy individuals was found in these regions by means of a PCR assay. Restriction enzyme polymorphism analysis by Southern blotting revealed that all North African EBV variants have a conserved restriction site on BamHI W'-I' and XhoI LMP gene. No additional BamHI enzyme site on the BamHI-F fragment was observed; however, the presence of an extra BamHI site on the BamHI-H fragment giving 2 HI and H2 fragment-like EBV M-ABA strains was found. All EBV strains present in NPC or NCI biopsies at all ages were homogeneous in these polymorphisms and no correlation was observed between the EBV genotypes from NPC patients and clinical stages of the cancer. These characteristics revealed a significant difference between the EBV variants common in Chinese NPC and those in North African NPC.

Co-existence of the A and B types of Epstein-Barr virus DNA in lymph node biopsies from Algerian patients with Hodgkin's disease and non-Hodgkin's lymphoma.

The association of Epstein-Barr virus (EBV) with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) was examined in Algerian patients. The DNA extracted from fresh lymph node biopsies of 17 HD and five NHL was analysed by polymerase chain reaction (PCR). Fifteen out of 17 biopsies (88%) from HD contained EBV genome. Viral type analysis showed the coexistence of A and B types of EBV in 14 biopsies (93%), and the sole presence of A type virus in one biopsy. Among five NHL biopsies examined, four biopsies contained both A and B types of EBV, while one revealed A type-virus only. This co-infection of Algerian HD and NHL patients does not seem to be related with any histologic form of these diseases. The analysis of viral types in the saliva from 12 Algerian healthy individuals revealed six EBV positives with only one A type. Two types of lymphoma in Algeria therefore are closely associated with EBV, and are characterized by coinfection with A and B types of EBV.

Using the job-exposure matrix for elaborating job histories.

A first software (JHS) for the elaboration of job histories oriented toward risks was designed and results published In an article "A software for the elaboration of Job Histories". This article presents a second software (JES), based on the use of a job-exposure matrix designed for one company. The matrix is essentially a database, an organized gathering of information concerning the company. The two softwares are inter-faced and both run on a PC. When properly exploited, the two softwares can serve as an asset for epidemiological studies dealing with occupational health.