[Impact of partial nephrectomy in a hybrid operating room on the activity of kidney cancer surgery]. / Évaluation de l'utilisation de la salle hybride sur l'activité de chirurgie en cancérologie rénale.

INTRODUCTION: Partial nephrectomy (NP) after embolization of tumor vessels (NPESH) in a hybrid room combines embolization of tumor vessels and enucleation of the tumor under laparoscopy in the same operative time. The purpose of this study was to assess the impact of the use of NPESH in the management of patients treated with surgery for a localized kidney tumor. MATERIAL AND METHODS: Using the uroCCR database, we included all consecutive patients operated in a university hospital for localized kidney tumor. From 2011 to May 2015, patients were treated by Standard Partial Nephrectomy (NPS) Laparoscopic or Open and from May 2015 to May 2019 by NPESH. We evaluated characteristics of patients, tumors, perioperative data and complications. These data were compared by Student and Khi2 tests. RESULTS: 87 NPS were performed during Period 1 and 137 NPS were performed during period 2. The ASA score of patients undergoing NPESH was higher than NPS (P<0.0001). The tumor complexity and median tumor size were similar in the two groups (P=0.852 and P=0.48). The complication rate for NPS and NPESH was 55.2% and 33.6% (P=0.002). There were less severe complications in the NEPSH group (P=0.012). The median length of stay was 8 and 4 days for the NPS and NPESH groups (P<0.0001). Positive surgical margins were 2 (2.3%) and 6 (4.6%) for the NPS and NPESH group (P=0.713). DISCUSSION: NPESH is an efficient technique compared to NPS. It seems to be an interesting alternative to limit renal ischemia, complication rate and length of stay for the management of localized kidney tumors.

Decoupling of differentiation between traits and their underlying genes in response to divergent selection.

We dissected the relationship between genetic differentiation (Q(ST)) for a trait and its underlying genes (G(STq), differentiation for a quantitative locus) in an evolutionary context, with the aim of identifying the conditions in which these two measurements are decoupled. We used two parameters (θ(B) and θ(W)) scaling the contributions of inter- and intrapopulation allelic covariation between genes controlling the trait of interest. We monitored the changes in θ(B) and θ(W), Q(ST) and G(STq) over successive generations of divergent and stabilizing selection, in simulations for an outcrossing species with extensive gene flow. The dynamics of these parameters are characterized by two phases. Initially, during the earliest generations, differentiation of the trait increases very rapidly and the principal and immediate driver of Q(ST) is θ(B). During subsequent generations, G(STq) increases steadily and makes an equal contribution to Q(ST). These results show that selection first captures beneficial allelic associations at different loci at different populations, and then targets changes in allelic frequencies. The same patterns are observed when environmental change modifies divergent selection, as shown by the very rapid response of θ(B) to the changes of selection regimes. We compare our results with previous experimental findings and consider their relevance to the detection of molecular signatures of natural selection.

Genetic variation and population structure in black-grass (Alopecurus myosuroides Huds.), a successful, herbicide-resistant, annual grass weed of winter cereal fields.

Black-grass (Alopecurus myosuroides) is an allogamous grass weed common in cereal fields of northern Europe, which developed resistance to a widely used family of herbicides, the ACCase-inhibiting herbicides. Resistance is caused by mutations at the ACCase gene and other, metabolism-based, mechanisms. We investigated the genetic structure of 36 populations of black-grass collected in one region of France (Côte d'Or), using 116 amplified fragment length polymorphism (AFLP) loci and sequence data at the ACCase gene. The samples were characterized for their level of herbicide resistance and genotyped for seven known ACCase mutations conferring resistance. All samples contained herbicide-resistant plants, and 19 contained ACCase mutations. The genetic diversity at AFLP loci was high (H(T) = 0.246), while differentiation among samples was low (F(ST) = 0.023) and no isolation by distance was detected. Genetic diversity within samples did not vary with the frequency of herbicide resistance. A Bayesian algorithm was used to infer population structure. The two genetic clusters inferred were not associated with any geographical structure or with herbicide resistance. A high haplotype diversity (H(d) = 0.873) and low differentiation (G(ST) = 0.056) were observed at ACCase. However, haplotype diversity within samples decreased with the frequency of ACCase-based resistance. We suggest that the genetic structure of black-grass is affected by its recent expansion as a weed. Our data demonstrate that the strong selection imposed by herbicides did not modify the genome-wide genetic structure of an allogamous weed that probably has large effective population sizes. Our study gives keys to a better understanding of the evolution of successful, noxious weeds in modern agriculture.

Variation at two flowering time genes within and among populations of Arabidopsis thaliana: comparison with markers and traits.

Flowering Locus C (FLC) and Frigida are two interacting genes controlling flowering time variation in Arabidopsis thaliana. Variation at these genes was surveyed in 12 A. thaliana populations sampled in France. These populations were also screened for variation at molecular markers [12 microsatellites and 19 cleaved amplified polymorphic sequence (CAPS) markers] and at seven quantitative traits measured with and without vernalization. Seven populations were highly polymorphic at markers (H(S) = 0.57 at microsatellites, 0.24 at CAPS) and showed heritable variation for bolting time and some other traits. Five populations were genetically fixed or nearly fixed. Q(ST) for bolting time without vernalization was significantly higher than F(ST), suggesting local divergent selection. One of the two haplotype groups at FLC (FLC(A)) was very predominant (frequency of 99%). The first exon of Frigida showed elevated nonsynonymous variation, and nine loss-of-function mutations were found throughout the gene. The association between loss-of-function and earlier bolting was confirmed. Overall, 18 Frigida haplotypes were detected. The pattern of variation at Frigida was largely similar to that found at markers and traits, with the same populations being fixed or highly diverse. Metapopulation dynamics is thus probably the main factor shaping genetic variation in A. thaliana. However, F(ST) for functional (FRI) vs. nonfunctional (FRI(Delta)) haplotypes was significantly higher than F(ST) at markers. This suggested that loss-of-function at Frigida is under local selection for flowering time.

Sampling within the genome for measuring within-population diversity: trade-offs between markers.

Experimental results of diversity estimates in a set of populations often exhibit contradictory patterns when different marker systems are used. Using simulations we identified potential causes for these discrepancies. These investigations aimed also to detect whether different sampling strategies of markers within the genome resulted in different estimates of the diversity at the whole genome level. The simulations consisted in generating a set of populations undergoing various evolutionary scenarios which differed by population size, migration rate and heterogeneity of gene flow. Population diversity was then computed for the whole genome and for subsets of loci corresponding to different marker techniques. Rank correlation between the two measures of diversity were investigated under different scenarios. We showed that the heterogeneity of genetic diversity either between loci (genomic heterogeneity, GH) or among populations (population heterogeneity, PH) varied greatly according to the evolutionary scenario considered. Furthermore, GH and PH were major determinants of the level of rank correlation between estimates of genetic diversities obtained using different kinds of markers. We found a strong positive relationship between the level of the correlation and PH, whatever the marker system. It was also shown that, when GH values were constantly low during generations, a reduced number of microsatellites was enough to predict the diversity of the whole genome, whereas when GH increased, more loci were needed to predict the diversity and amplified fragment length polymorphism markers would be more recommended in this case. Finally the results are discussed to recommend strategies for gene diversity surveys.

Phylogeographic structure of white oaks throughout the European continent.

Patterns of chloroplast DNA (cpDNA) variation were studied in eight white oak species by sampling 345 populations throughout Europe. The detection of polymorphisms by restriction analysis of PCR-amplified cpDNA fragments allowed the identification of 23 haplotypes that were phylogenetically ordered. A systematic hybridization and introgression between the eight species studied is evident. The levels of subdivision for unordered (GST) and ordered (NST) alleles are very high and close (0.83 and 0.85). A new statistical approach to the quantitative study of phylogeography is presented, which relies on the coefficients of differentiation GST and NST and the Mantel's test. Based on pairwise comparisons between populations, the significance of the difference between both coefficients is evaluated at a global and a local scale. The mapped distribution of the haplotypes indicates the probable routes of postglacial recolonization followed by oak populations that had persisted in southern refugia, especially in the Iberian peninsula, Italy and the Balkans. Most cpDNA polymorphisms appear to be anterior to the beginning of the last recolonization. A subset of the preexisting haplotypes have merely expanded north, while others were left behind in the south.

Assessment of the type and degree of restriction fragment length polymorphism (RFLP) in diploid species of the genus Triticum.

The A genome of the Triticeae is carried by three diploid species and subspecies of the genus Triticum: T. monococcum ssp. monococcum, T. monococcum ssp. boeoticum, and T. urartu, the A-genome donor of bread wheat. These species carry many genes of agronomic interest, including disease resistances, and may also be used for the genetic mapping of the A genome. The aim of this study was to evaluate the variability present in a sample of 25 accessions representative of this group using RFLP markers. Twenty probes, consisting of genomic DNA or cDNA from wheat, were used in combination with four restriction enzymes. A high level of polymorphism was found, especially at the interspecific level. Selecting the most informative enzymes appeared to be of great importance in order to obtain a stable structure for the diversity observed with only 20 probes. The results are largely consistent with taxonomy and data relating to geographical origins. The probes were also tested on 14 wheat cutivars. A good correlation coefficient was found for their informative values on wheat cultivars and diploid lines. Whether the group of species studied here would be useful for genetic mapping remains to be determined. Nevertheless, RFLP markers will be useful to follow genes that can possibly be introgressed from these species into cultivated wheat.