Dispersal capacities of pollen, seeds and spores: insights from comparative analyses of spatial genetic structures in bryophytes and spermatophytes.

Introduction: The dramatic fluctuations of climate conditions since the late Tertiary era have resulted in major species range shifts. These movements were conditioned by geographic barriers and species dispersal capacities. In land plants, gene flow occurs through the movement of male gametes (sperm cells, pollen grains), which carry nDNA, and diaspores (spores, seeds), which carry both cpDNA and nDNA, making them an ideal model to compare the imprints of past climate change on the spatial genetic structures of different genomic compartments. Based on a meta-analysis of cpDNA and nDNA sequence data in western Europe, we test the hypotheses that nDNA genetic structures are similar in bryophytes and spermatophytes due to the similar size of spores and pollen grains, whereas genetic structures derived from the analysis of cpDNA are significantly stronger in spermatophytes than in bryophytes due to the substantially larger size of seeds as compared to spores. Methods: Sequence data at 1-4 loci were retrieved for 11 bryophyte and 17 spermatophyte species across their entire European range. Genetic structures between and within southern and northern populations were analyzed through F and N statistics and Mantel tests. Results and discussion: Gst and Nst between southern and northern Europe derived from cpDNA were significantly higher, and the proportion of significant tests was higher in spermatophytes than in bryophytes. This suggests that in the latter, migrations across mountain ranges were sufficient to maintain a homogenous allelic structure across Europe, evidencing the minor role played by mountain ranges in bryophyte migrations. With nDNA, patterns of genetic structure did not significantly differ between bryophytes and spermatophytes, in line with the hypothesis that spores and pollen grains exhibit similar dispersal capacities due to their size similarity. Stronger levels of genetic differentiation between southern and northern Europe, and within southern Europe, in spermatophytes than in bryophytes, caused by higher long-distance dispersal capacities of spores as compared to seeds, may account for the strikingly higher levels of endemism in spermatophytes than in bryophytes in the Mediterranean biodiversity hotspot.

Disentangling the roles of chance, abiotic factors and biotic interactions among epiphytic bryophyte communities in a tropical rainforest (Yunnan, China).

Epiphytes offer an appealing framework to disentangle the contributions of chance, biotic and abiotic drivers of species distributions. In the context of the stress-gradient theory, we test the hypotheses that (i) deterministic (i.e., non-random) factors play an increasing role in communities from young to old trees, (ii) negative biotic interactions increase on older trees and towards the tree base, and (iii) positive interactions show the reverse pattern. Bryophyte species distributions and abiotic conditions were recorded on a 1.1 ha tropical rainforest canopy crane site. We analysed co-occurrence patterns in a niche modelling framework to disentangle the roles of chance, abiotic factors and putative biotic interactions among species pairs. 76% of species pairs resulted from chance. Abiotic factors explained 78% of non-randomly associated species pairs, and co-occurrences prevailed over non-coincidences in the remaining species pairs. Positive and negative interactions mostly involved species pairs from the same versus different communities (mosses versus liverworts) and life forms, respectively. There was an increase in randomly associated pairs from large to small trees. No increase in negative interactions from young to old trees or from the canopy to the base was observed. Our results suggest that epiphytic bryophyte community composition is primarily driven by environmental filtering, whose importance increases with niche complexity and diversity. Biotic interactions play a secondary role, with a very marginal contribution of competitive exclusion. Biotic interactions vary among communities (mosses versus liverworts) and life forms, facilitation prevailing among species from the same community and life form, and competition among species from different communities and life forms.

Five-year outcomes of rapid-deployment aortic valve replacement with the Edwards Intuity valve.

BACKGROUND: This report presents 5-year outcomes of the rapid-deployment Edwards Intuity valve in a prospective, single-center study. METHODS: All patients who underwent an aortic valve replacement (AVR) with an Edwards Intuity bioprosthesis at La Timone Hospital, Marseille, France, from July 2012 to June 2015 were assessed over a 5-year follow-up period. The primary outcome was overall mortality at 5 years. Secondary outcomes were reoperation, overall mortality and stroke, cardiovascular mortality, composite endpoints defined by the updated Valve Academic Research Consortium-2 (VARC-2), periprosthetic regurgitation, prosthesis-patient mismatch, and the need for new pacemaker implantation. RESULTS: In total, 170 consecutive patients were assessed, of which 67.1% were males. The mean age was 76 years, mean EuroSCORE II was 3.5% and 5-year overall mortality was 12.4%. At 5 years, reoperation was 2.9%, overall mortality and stroke was 4.1% per patient-year, and cardiovascular mortality was 4.7%. VARC clinical efficacy and VARC time-related valve safety were achieved in 46.0% and 59.9% of patients, respectively. At one month VARC device success was 71.2% and VARC early safety was 87.1%. At one year, mild and moderate periprosthetic regurgitation were 2.4% and 0.6%, respectively, and moderate and severe prosthesis-patient mismatch were 18.8% and 4.8%, respectively. Conduction disturbances needing new PPI occurred in 3.5% patients. CONCLUSION: The 5-year outcomes of AVR with the Edwards Intuity valve system demonstrate satisfactory midterm safety and excellent haemodynamic performance.

[COVID-19 inside dialysis units]. / La dialyse chronique face à la COVID-19.

COVID-19 has been the center of global attention and concern for the last months. Patients undergoing dialysis and especially those treated at the hospital are likely to be infected, due to their mandatory presence at the hospital several times a week and due to their intrinsic fragility in regard of chronic kidney disease, often an older age, and the presence of many associated comorbidities. Thereby, patients with chonic kidney disease treated by haemodialysis have higher odds of a more severe COVID-19 infection with a high mortality rate. Prevention is thus a high priority for these patients.

Au cours des derniers mois, la COVID-19 a été au centre des préoccupations et de l'attention de chacun. Les patients dialysés, et surtout ceux hémodialysés en centre, représentent une population particulièrement à risque de contamination vu la nécessité de se rendre à l'hôpital plusieurs fois par semaine et compte tenu de leur fragilité intrinsèque liée au statut de malade rénal chronique, un âge souvent plus avancé, et de nombreuses comorbidités. Ils ont donc un risque de développer une infection grave et potentiellement mortelle. Dès lors, la stratégie de prévention est d'une importance capitale pour ces patients.

Bryophytes are predicted to lag behind future climate change despite their high dispersal capacities.

The extent to which species can balance out the loss of suitable habitats due to climate warming by shifting their ranges is an area of controversy. Here, we assess whether highly efficient wind-dispersed organisms like bryophytes can keep-up with projected shifts in their areas of suitable climate. Using a hybrid statistical-mechanistic approach accounting for spatial and temporal variations in both climatic and wind conditions, we simulate future migrations across Europe for 40 bryophyte species until 2050. The median ratios between predicted range loss vs expansion by 2050 across species and climate change scenarios range from 1.6 to 3.3 when only shifts in climatic suitability were considered, but increase to 34.7-96.8 when species dispersal abilities are added to our models. This highlights the importance of accounting for dispersal restrictions when projecting future distribution ranges and suggests that even highly dispersive organisms like bryophytes are not equipped to fully track the rates of ongoing climate change in the course of the next decades.

Cardiac magnetic resonance assessment of left ventricular dilatation in chronic severe left-sided regurgitations: comparison with standard echocardiography.

PURPOSE: The purpose of this study was to investigate the potential additional value of cardiac magnetic resonance (CMR) in the assessment of left ventricular (LV) dilatation and dysfunction by comparison to standard echocardiography in patients with chronic left-sided valvular regurgitation. MATERIALS AND METHODS: We prospectively enrolled patients with chronic severe mitral regurgitation (MR) or aortic regurgitation (AR). They underwent standard echocardiography and CMR using aortic flow and LV-function sequences. LV dilatation or dysfunction was assessed with each technique, based on thresholds used for surgery indication. Reference regurgitation severity was defined following previously reported CMR-based regurgitant volume thresholds. RESULTS: A total of 71 patients with chronic severe MR (n=44) or severe AR (n=27) were prospectively included. There were 60 men and 11 women with a mean age of 61±14 (SD) years (range: 18-83 years). CMR-based regurgitation severity was significantly greater in the LV dysfunction group when assessed with CMR (MR, P=0.011; AR, P=0.006) whereas it was not different when LV dysfunction was assessed using standard echocardiography. Among standard echocardiography and CMR volumetric indices, CMR-derived end-diastolic volume showed the best ability to predict regurgitation severity (area under the curve [AUC]=0.78 for MR; AUC=0.91 for AR). Diagnostic thresholds identified on receiver operating characteristics-curve analysis were lower than those of current European recommendations and closer to North-American guidelines. CONCLUSION: CMR assessment of LV end-diastolic volume in chronic severe left-sided regurgitations is more reliably associated with CMR-based regurgitant volume by comparison with standard echocardiography diameter. CMR may provide useful evaluation before surgery decision for severe asymptomatic regurgitations.

Value of CMR in quantification of paravalvular aortic regurgitation after TAVI.

AIMS: To assess the value of cardiac magnetic resonance (CMR) using phase-contrast velocity mapping for paravalvular aortic regurgitation (PAR) quantification. METHODS AND RESULTS: All patients undergoing transcatheter aortic valve implantation (TAVI) in our centre between November 2012 and August 2013, without CMR-contraindication were included. PAR severity was assessed 5 days after TAVI using: transthoracic echocardiography (TTE) and CMR [regurgitant volume (RV), regurgitant fraction (RF)]. Aortic regurgitation (AR) index was obtained during TAVI. Thirty of 51 patients who underwent TAVI were included (COREVALVE, n = 10; or EDWARDS SAPIEN XT, n = 20). At TTE, PAR was mild in 22, moderate in 3, and severe in 5 patients. Reliable phase-contrast images were acquired at the sino-tubular junction for SAPIEN and at the tubular portion of the ascending aorta for COREVALVE. The reproducibility of CMR was high (coefficient of correlation = 0.99 for intra- and inter-operator variability). At CMR, RV, and RF were significantly (P < 0.0005) correlated with AR severity at TTE, with mean RF values at 9.2 ± 7.6% in mild, 20.3 ± 4.2% in moderate, and 46.8 ± 10.8% in severe PAR. A cut-off value of RF < 14% at CMR accurately discriminated mild from moderate/severe (sensitivity: 100%, specificity: 82%). The mean AR index was 29.4 ± 6 for mild and 13.8 ± 5 for moderate/severe PAR. Three patients had a RF > 14% and a low AR index <25 despite a mild PAR at TTE, suggesting an underestimation at TTE. CONCLUSION: CMR is a reproducible, accurate, and reliable method to assess PAR severity. CMR may allow correcting an underestimation at TTE when AR index is doubtful.

Alcohol-induced hypertension: an important healthcare target in Belgium.

Excessive alcohol intake is one of the leading causes of premature death in Europe and particularly in Belgium. Belgian people are consuming more alcohol per year than the European average. It is well established that excessive alcohol consumption is a significant predictor of the development of hypertension (HTN). Two million adults in Belgium suffer from HTN and this number will increase to three million by 2025. Less than 50% of Belgian people treated for HTN are well-controlled. Alcohol reduction in patients with HTN can significantly lower systolic and diastolic blood pressure. After reviewing the epidemiology of HTN and alcohol disorders in Belgium, this paper will focus on the rationale for alcohol screening and brief intervention in primary care. It will also describe the barriers to alcohol screening, and what could be the benefits of alcohol screening for our healthcare system. The authors believe that early identification through alcohol screening and brief intervention in general practice can help to improve the management of patients with HTN, to reach the targets of the WHO Global Action Plan, i.e., a 25% relative reduction in the risk of premature mortality from cardiovascular diseases, cancer, diabetes or chronic respiratory diseases. They are also convinced that this would allow achieving major healthcare savings.

Prone positioning during veno-venous extracorporeal membrane oxygenation for severe acute respiratory distress syndrome in adults.

BACKGROUND: Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is an effective rescue therapy for improving oxygenation in selected severe acute respiratory distress syndrome (ARDS). Prone position (PP) is usually considered before vvECMO and few data are available on the association of PP during VV-ECMO. Thus, we investigated the effect on oxygenation and the safety of PP during vvECMO. METHODS: During a two-year period, 15 patients with severe ARDS were turned into PP during VV-ECMO therapy for at least one of the three following conditions: severe hypoxemia (PaO2/FiO2 ratio below 70) despite maximal oxygenation, injurious ventilation parameters with plateau pressure exceeding 32 cmH2O or failure of attempt to wean ECMO after at least 10 days on ECMO support. RESULTS: PP was considered after a median of 9 days of ECMO and applied for a median of 12 hours and an average of 1.4 sessions per patient resulting in a total of 21 procedures. We found significant improvement in PaO2/FiO2 ratio at 6 hours (P=0.03) and 12 hours (P=0.007) after reversal. The improvement in oxygenation has still persisted 1hour (P=0.017) and 6 hours (P=0.013) after back to the supine position. No change in PaCO2, respiratory system (RS) compliance was observed. ECMO flow was maintained constant during the procedure. No complication related to PP was detected. CONCLUSION: PP may be considered in selected patients difficult to wean or remaining very hypoxemic despite VV-ECMO support.

Survival in dialysis patients is different between patients with diabetes as primary renal disease and patients with diabetes as a co-morbid condition.

AIMS/HYPOTHESIS: A previous study in Dutch dialysis patients showed no survival difference between patients with diabetes as primary renal disease and those with diabetes as a co-morbid condition. As this was not in line with our hypothesis, we aimed to verify these results in a larger international cohort of dialysis patients. METHODS: For the present prospective study, we used data from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry. Incident dialysis patients with data on co-morbidities (n = 15,419) were monitored until kidney transplantation, death or end of the study period (5 years). Cox regression was performed to compare survival for patients with diabetes as primary renal disease, patients with diabetes as a co-morbid condition and non-diabetic patients. RESULTS: Of the study population, 3,624 patients (24%) had diabetes as primary renal disease and 1,193 (11%) had diabetes as a co-morbid condition whereas the majority had no diabetes (n = 10,602). During follow-up, 7,584 (49%) patients died. In both groups of diabetic patients mortality was higher compared with the non-diabetic patients. Mortality was higher in patients with diabetes as primary renal disease than in patients with diabetes as a co-morbid condition, adjusted for age, sex, country and malignancy (HR 1.20, 95% CI 1.10, 1.30). An analysis stratified by dialysis modality yielded similar results. CONCLUSIONS/INTERPRETATION: Overall mortality was significantly higher in patients with diabetes as primary renal disease compared with those with diabetes as a co-morbid condition. This suggests that survival in diabetic dialysis patients is affected by the extent to which diabetes has induced organ damage.

[The follow-up of chronic renal failure]. / Le suivi de l'insuffisance rénale chronique.

The follow-up of chronic kidney failure is a long and complex process. The diagnosis of the kidney disease and the level of renal failure have first to be established. A strategy for slowing the evolution of chronic kidney disease has to be build. The blockade of the renin angiotensin system and the control of the cardiovascular risk factors are the main components of this strategy. The evaluation and the treatment of the classical complications of chronic kidney disease should also take place. Correction of anemia, and of phosphocalcic complications need specific therapies. Preparation for dialysis and transplantation have to be taken into account. Such a follow-up deserves a close collaboration between general practitioners and nephrologists.

[MESRCA/MESRRA: material aspects]. / UMAC / UMAR: aspects matériels.

Mobile ECMO support for remote cardiac or respiratory assistance (MESRCA and MESRRA) allows mobilization of the medical and paramedical team 24/7 in a very large geographical area. Mobility and autonomy require adapted devices. During many years, teams had to deal with non useful equipment. Recently, thanks to interest of medical world and laboratories, many materials especially suitable for this activity are developed. We describe our local experience and solutions we tented to fi nd to deal with material difficulties.

Clinical characteristics and outcome of infective endocarditis in adults with bicuspid aortic valves: a multicentre observational study.

OBJECTIVE: To analyse characteristics and outcomes of infective endocarditis (IE) on bicuspid aortic valves (BAV) and to compare the risk of death according to the presence or absence of BAV. DESIGN: 5-year observational study. SETTING: Population of 856 patients with definite IE according to the Duke criteria from two tertiary centres (Amiens and Marseille, France). PATIENTS: 310 consecutive patients with definite native aortic valve IE enrolled between 1991 and 2007. INTERVENTIONS: Patients underwent transthoracic and transoesophageal echocardiography during hospitalisation. Surgery was performed on a case-by-case basis according to conventional guidelines. MAIN OUTCOME MEASURES: In-hospital mortality and 5-year overall mortality. RESULTS: Patients with BAV IE (n=50, 16%) were younger, had fewer comorbidities and a higher frequency of aortic perivalvular abscess (50%). Presence of BAV (OR 3.79 (1.97-7.28); p<0.001) was independently predictive of abscess formation. Early surgery was performed in 36 BAV patients (72%) with a peri-operative mortality of 8.3%, comparable to that of patients with tricuspid aortic valve IE (p=0.89). BAV was not independently predictive of in-hospital mortality (OR 0.89 (0.28-2.85); p=0.84) or 5-year survival (HR 0.71 (0.37-1.36); p=0.30). Age, comorbidities, heart failure, Staphylococcus aureus and uncontrolled infection were associated with increased 5-year mortality in BAV patients. CONCLUSION: BAV is frequent in adults with native aortic valve IE. Patients with BAV IE incur high risk of abscess formation and require early surgery in almost three-quarters of cases. IE is a severe complication in the setting of BAV and warrants prompt diagnosis and treatment.

[Cardiac tumors]. / Les tumeurs cardiaques.

Primary cardiac tumor is a rare disease, with an incidence ranging from 0.001 to 0.03%. Eighty percent of them are benign tumors, and among them 70% are myxomas, the others are: fibroelastoma, rhabdomyoma, fibroma, angioma and lipoma. Primary malignant tumors of heart are in 95% of cases sarcomas, the remaining 5% are lymphomas. Cardiac's metastases are more frequent than primary tumors. Diagnosis is made by echocardiography TAC and MRI. Whereas surgery is indicated in patients with benign tumors, or localised sarcomas, chemotherapy in those with widespread disease and radiotherapy and chemotherapy in lymphoma. Prognosis is excellent in benign cardiac tumor. Mean survival for sarcomas is 11 months, and lymphoma 5 years.

X-ray crystal structure of GarR-tartronate semialdehyde reductase from Salmonella typhimurium.

Tartronate semialdehyde reductases (TSRs), also known as 2-hydroxy-3-oxopropionate reductases, catalyze the reduction of tartronate semialdehyde using NAD as cofactor in the final stage of D-glycerate biosynthesis. These enzymes belong to family of structurally and mechanically related beta-hydroxyacid dehydrogenases which differ in substrate specificity and catalyze reactions in specific metabolic pathways. Here, we present the crystal structure of GarR a TSR from Salmonella typhimurium determined by the single-wavelength anomalous diffraction method and refined to 1.65 A resolution. The active site of the enzyme contains L-tartrate which most likely mimics a position of a glycerate which is a product of the enzyme reaction. The analysis of the TSR structure shows also a putative NADPH binding site in the enzyme.

[World kidney Day 2008: the impact of epidemiology of kidney diseases in Belgium]. / Journée Mondiale du Rein 2008 : impact de l'epidémiologie des maladies rénales en Belgique.

The World Kidney Day offers a crucial opportunity to the Belgian associations of nephrologists to inform public and medical communities about the global problem of chronic kidney disease (CKD). According to epidemiological data from GNFB/ NBVN registries in our country, cardiovascular diseases and diabetes 2 are responsible for an increasing amount of CKD cases with pejorative evolution to end-stage renal disease requiring cost-effective renal replacement therapies (haemodialysis, peritoneal dialysis or renal transplantation). In these patients, the high level of comorbidities and the late referral to the nephrologists are recognized as enhanced morbidity and mortality factors. These facts underline the need for the nephrologists to stimulate collaboration with general practitioners and specialists from other disciplines in order to set up systematic screening procedures and early follow-up of patients at risk of developing CKD. These procedures should contribute to reduce the progression rate of renal function impairment.

[Surgical management of cardiac wounds: cardiac or general surgical service?]. / Plaies du coeur, prise en charge de chirurgie cardiaque ou générale?

OBJECTIVE: To define modalities of cardiac wound management with a special emphasis on the initial direction of the patient toward a surgical service, rapid diagnosis, and surgical treatment. METHOD: Sixteen patients with thoracic injury to the region of the heart treated between 1996 and 2006 were evaluated retrospectively. Pre-operative clinical data, echography, and CT results were collected; time elapsed between injury and treatment, type of surgical treatment, use of cardio-pulmonary bypass, morbidity and mortality were evaluated. RESULTS: There were 16 patients (12 men); age ranged from 18 to 80 with an average of 45.7 years. Nine patients had penetrating cardiac wounds, two had blunt trauma, and five suffered iatrogenic trauma. Cardio-pulmonary bypass was used in two cases. The mean time elapsed between trauma and surgical evaluation was 63 minutes (p=0.18). In all cases, surgery consisted of a myorraphy without coronary or valvular repair. Post-operative complications occurred in 4 patients (25%) and resulted in 2 deaths (12.5%). Complication and death were associated with a prolonged interval between injury and surgical management. CONCLUSION: Patients with cardiac wounds should be transported to the nearest surgical hospital. There are no benefits to cardio-pulmonary bypass in cardiac trauma.

Infective endocarditis incidentally discovered by pathological examination.

We present three patients in whom a cardiac valve replacement was needed because of degenerative and supposed non-infectious damage. The excised valves showed histological features of infective endocarditis with detection of micro-organisms. This diagnosis of infective endocarditis was confirmed by other diagnostic methods. Pathological examination of cardiac valves remains the gold standard for the diagnosis of infective endocarditis, and it should be routinely performed even without suspicion of infectious process.

[Heavy-hearted: chronic constrictive pericarditis]. / "Un coeur serré": péricardite chronique constrictive.

The purpose of this report is to describe a case involving a 62-year-old Moroccan woman hospitalized for generalized edema that lead to diagnosis of chronic constrictive pericarditis. Diagnosis was confirmed on the basis of pericardial calcification and typical hemodynamic findings. New imaging techniques such as cardiac MRI allow accurate anatomical and physiological assessment in difficult cases. While tuberculosis is rarely involved in industrialized countries, it is a frequent factor in developing countries. The usual treatment consists of pericardectomy in association with standard antituberculosis drugs if association with tuberculosis is established or highly likely.