Traitements nématicides et peuplement de nématodes parasites de la canne à sucre au Burkina Faso : 1. Repousses

International audienceNematicides and nematode community parasitic on sugarcane in Burkina Faso. 1. Ratoon cane Triadic analysis of three ways tables provides a means for studying the effect of nematicide treatments applied on sugarcane ratoons upon nematodes populations dynamics, by taking into account the between-plots variability of nematodes numbers. Only fumigation applied before planting has markedly reduced the size of the community. The treatments applied in ratoons next years has only a moderate effect upon nematode multiplication. For al! the treatments that we have compared, the size of the community tends to increase from ratoon to ratoon. Oxamyl, carbofuran and aldicarb, employed in ratoon, modify the balance between endoparasitic populations; their application is followed by the formation of a community dominated by Meloidogyne and Pratylenchus at the end of the crop. However, on the control, after the second ratoon the populations of Paratylenchus, Hoplo/aimus and Heterodera become more important than the populations of Meloidogyne and Pratylenchus. Helicotylenchus is more influenced by seasonal fluctuations than by treatments.L'analyse triadique de tableaux multiples a permis d'extraire les contraintes imposées à la dynamique des populations de nématodes par l'application de traitements nématicides sur des repousses de canne à sucre, sans éliminer la variabilité interparcellaire. Seule la fumigation effectuée avant la plantation a provoqué une baisse importante du volume du peuplement. Les traitements appliqués les années suivantes en repousse n'affectent que modérément la multiplication des nématodes. Dans toutes les séquences de traitements comparées, le volume du peuplement a tendance à s'accroître au fil des repousses. Oxamyl, carbofuran et aldicarbe, employés en repousse, modifient l'équilibre entre les populations d'endoparasites; ils conduisent à la constitution d'un peuplement dominé par Meloidogyne et Pratylenchus en fin de cycle. Par contre sur le témoin, à partir de la seconde repousse, les populations de Paratylenchus, Hoplolaimus et Heterodera deviennent plus importantes que celles de Meloidogyne et Pratylenchus. Helicotylenchus est plus affecté par les fluctuations saisonnières que par les traitements

African-American patients with cancer Talking About Clinical Trials (TACT) with oncologists during consultations: evaluating the efficacy of tailored health messages in a randomised controlled trial—the TACT study protocol

Introduction Low rates of accrual of African-American (AA) patients with cancer to therapeutic clinical trials (CTs) represent a serious and modifiable racial disparity in healthcare that impedes the development of promising cancer therapies. Suboptimal physician–patient consultation communication is a barrier to the accrual of patients with cancer of any race, but communication difficulties are compounded with AA patients. Providing tailored health messages (THM) to AA patients and their physician about CTs has the potential to improve communication, lower barriers to accrual and ameliorate health disparities. Objective (1) Demonstrate the efficacy of THM to increase patient activation as measured by direct observation. (2) Demonstrate the efficacy of THM to improve patient outcomes associated with barriers to AA participation. (3) Explore associations among preconsultation levels of: (A) trust in medical researchers, (B) knowledge and attitudes towards CTs, (C) patient-family member congruence in decision-making, and (D) involvement/information preferences, and group assignment. Methods and analysis First, using established methods, we will develop THM materials. Second, the efficacy of the intervention is determined in a 2 by 2 factorial randomised controlled trial to test the effectiveness of (1) providing 357 AA patients with cancer with THM with 2 different ‘depths’ of tailoring and (2) either providing feedback to oncologists about the patients\u27 trial THM or not. The primary analysis compares patient engaged communication in 4 groups preconsultation and postconsultation. Ethics and dissemination This study was approved by the Virginia Commonwealth University Institutional Review Board. To facilitate use of the THM intervention in diverse settings, we will convene ‘user groups’ at 3 major US cancer centres. To facilitate dissemination, we will post all materials and the implementation guide in publicly available locations

Toward the understanding of DNA fluorescence : The singlet excimer of cytosine

By using the multiconfigurational second-order perturbation method CASPT2, including corrections for the basis set superposition error, the lowest-singlet excited state of the face-to-face π-stacked cytosine homodimer is revealed to be bound by about half an eV, being the source of an emissive feature consistent with the observed redshifted [email protected] [email protected] [email protected] [email protected]

Dextran sulfate enhances the level of an oxidative DNA damage biomarker, 8-oxo-7,8-dihydro-2'-deoxyguanosine, in rat colonic mucosa.

International audienceDextran sodium sulfate (DSS) given in drinking water can induce colonic inflammation and produce colorectal tumors in rodents, although it is not directly genotoxic. The hypothesis that DSS can produce free radicals and induce oxidative DNA damage in colonic mucosa has been tested. In rats fed for 2 days with water containing 3% and 6% DSS, colonic inflammation manifestations were recorded and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), a major biomarker of oxidative DNA damage, was assayed in colonic mucosa. As compared with control rats given pure water, inflammatory manifestations were seen in rats given DSS. At the same time, 8-oxodGuo levels in colonic mucosa were doubled (P < 0.001). These results suggest that formation of oxidative DNA damage in colonic mucosa depends on inflammation and maybe on the production of reactive oxygen species. This study shows that DSS can induce oxidative DNA damage within only 2 days, which could explain in part its carcinogenic properties

Biologically relevant oxidants and terminology, classification and nomenclature of oxidatively generated damage to nucleobases and 2-deoxyribose in nucleic acids

A broad scientific community is involved in investigations aimed at delineating the mechanisms of formation and cellular processing of oxidatively generated damage to nucleic acids. Perhaps as a consequence of this breadth of research expertise, there are nomenclature problems for several of the oxidized bases including 8-oxo-7,8-dihydroguanine (8-oxoGua), a ubiquitous marker of almost every type of oxidative stress in cells. Efforts to standardize the nomenclature and abbreviations of the main DNA degradation products that arise from oxidative pathways are reported. Information is also provided on the main oxidative radicals, non-radical oxygen species, one-electron agents and enzymes involved in DNA degradation pathways as well in their targets and reactivity. A brief classification of oxidatively generated damage to DNA that may involve single modifications, tandem base modifications, intrastrand and interstrand cross-links together with DNA-protein cross-links and base adducts arising from the addition of lipid peroxides breakdown products is also included

Comparación entre dos tipos de gastrostomías quirúrgicas, abierta y laparoscópica, en nutrición enteral domiciliaria

Objetivo: Exponer las complicaciones de las gastrostomías quirúrgicas utilizadas como vía de soporte nutricional enteral domiciliario (SNED) y detectar si existen diferencias entre las dos técnicas usadas en nuestro medio: Cirugía abierta vs laparoscópica. Material y métodos: Estudio observacional descriptivo de carácter retrospectivo de las gastrostomías quirúrgicas realizadas entre los años 1994 y 2009 seguidas por nuestra unidad. Se han analizado las complicaciones detectadas en consulta durante el seguimiento de pacientes con SNED a través de gastrostomía quirúrgica realizada con técnica laparotómica abierta vs laparoscópica, valorando: fuga del contenido gástrico al exterior, irritación de la pared abdominal, presencia de exudado, presencia de exudado con cultivo positivo que requirió tratamiento antibiótico, quemadura o pérdida de sustancia de la zona periostomía, rotura de balón, úlcera de decúbito por la sonda y formación de granuloma. Resultados: Durante los años 1994-2009 se realizaron 57 gastrostomías quirúrgicas: 47 por técnica laparótomica (abierta) convencional y 10 por vía laparoscópica. La edad media de los pacientes fue de 57,51 ± 17,29 años. La causa más frecuente que motivó la realización de la gastrostomía quirúrgica fue el cáncer de esófago (38,6%) seguido de alteraciones neurológicas (26,3%) y tumores de cabeza y cuello (26,3%). El 97,9% de los pacientes a los que se realizó una gastrostomía quirúrgica abierta presentaron al menos una complicación, es decir que solo el 2,1% estuvieron libres de complicaciones; mientras que el 50% de los que se sometieron a una gastrostomía laparoscópica no tuvo ninguna. Las complicaciones más frecuentes fueron la presencia de fuga del contenido gástrico y la irritación de la pared abdominal que se presentaron en el 89,4% y 83% respectivamente de las gastrostomías laparotómicas frente a la aparición de solo el 30% de ambas complicaciones en las gastrostomías laparoscópicas siendo la diferencia estadísticamente significativa (p Aim: Exposing the complications of surgical gastrostomies used as way of home enteral nutritional support (HEN) and detecting the differences between the two techniques used in our environment: Open Surgery vs Laparoscopic Surgery. Material and methods: Retrospective descriptive observational study of the surgical gastrostomies performed between 1994 and 2009 followed up by our unit. Have been analyzed the complications detected in our practice during the follow-up of patients with HEN performed via open laparotomy vs. laparoscopic tecniques, assessing: leaks of gastric fluid to the exterior, abdominal wall irritation, presence of exudate, presence of exudate with positive culture that required antibiotical treatment, burning or loss of substance of the periostomic zone, breach of balloon, decubitus ulcer caused by the tube and formation of granuloma. Results: Between 1994 and 2009, 57 surgical gastrostomies were performed: 47 using the conventional laparotomic (open) tecnique and 10 laparoscopies. The average age of the patients was 57.51 ± 17.29 years old. The most common cause for the performance of surgical gastrostomy was esophageal cancer (38.6%) followed by neurologic alterations (26.3%) and head and neck tumors (26.3%). 97.9% of the patients who underwent to surgical gastrostomy presented at least one complication, meaning that only 2.1% were free of complications; meanwhile, 50% of the patients were laparoscopic gastrostomy was performed had none of these complications. The most common complications were the presence of leaks of gastric fluid and abdominal wall irritation that appeared on 89.4% and 83% respectively of the laparotomic gastrostomies versus the presence of only 30% of both complications in laparoscopic gastrostomies being the difference statistically significant (p < 0.01). Conclusions: After the introduction of the laparoscopic technique in the performance of surgical gastrostomies has been observed a decrease of the complications occured during the home enteral nutritional support related to surgical gastrostomies

Jachères naturelles et restauration des propriétés des sols en zone semi-aride. Cas du Sénégal

L'objectif des travaux est d'analyser, dans une zone sahélo-soudanienn e fortement peuplée du Sénégal, les effets de jachères naturelles, d'âge et de gestion différents, sur les caractéristiques physico-chimiques et biologiques des sols. Avec une protection totale contre le pâturage et l'exploitation du bois, 15 ans de jachère permettent d'accroître les teneurs en matière organique de 50 %. La porosité totale de l'horizon de surface est multipliée par deux, l'abondance des macro-agrégats s'accroît de 50 à 70 % et la biomasse microbienne totale de 30 %. Quinze années de jachère protégée ne provoquent pas une baisse de la densité globale d'infestation en nématodes phytoparasites, mais modifient la composition spécifique du peuplement. Les jachères anciennes soumises à une forte pression d'exploitation présentent les mêmes tendances, mais montrent des teneurs en matière organique du sol inférieures d'environ 20 % à celles de parcelles protégées. Sur les jachères jeunes (3 années), le temps de culture précédant l'abandon culturel n'a pas d'influence significative sur les paramètres mesurés. Même si elle était réalisable, la jachère naturelle de longue durée ne possède plus les potentialités nécessaires à la restauration de la fertilité du milieu. II faut s'orienter vers des pratiques de jachères améliorées ou de substitution, en introduisant des ligneux et des graminées pérennes à forte biomasse racinaire et à croissance rapide, qui ont un fort impact sur les caractéristiques biologiques et physiques des sols. (Résumé d'auteur

A theoretical insight into the photophysics of psoralen

Psoralen photophysics has been studied on quantum chemistry grounds using the multiconfigurational second-order perturbation method CASPT2. Absorption and emission spectra of the system have been rationalized by computing the energies and properties of the low-lying singlet and triplet excited states. The S1 ππ* state has been determined to be responsible of the lowest absorption and fluorescence bands and to initially carry the population in the photophysical processes related to the phototherapeutic properties of psoralen derivatives. The low-lying T1 ππ* state is, on the other hand, protagonist of the phosphorescence, and its prevalent role in the reactivity of psoralen is suggested to be related to the elongation of the pyrone ring C3–C4 bond, where the spin density is distributed on both carbon atoms. Analysis of energy gaps and spin-orbit coupling elements indicates that the efficient photophysical process leading to the population of the lowest triplet state does not take place at the Franck-Condon region but along the S1 relaxation [email protected] [email protected] [email protected]

Combined CloudSat-CALIPSO-MODIS retrievals of the properties of ice clouds

In this paper, data from spaceborne radar, lidar and infrared radiometers on the “A-Train” of satellites are combined in a variational algorithm to retrieve ice cloud properties. The method allows a seamless retrieval between regions where both radar and lidar are sensitive to the regions where one detects the cloud. We first implement a cloud phase identification method, including identification of supercooled water layers using the lidar signal and temperature to discriminate ice from liquid. We also include rigorous calculation of errors assigned in the variational scheme. We estimate the impact of the microphysical assumptions on the algorithm when radiances are not assimilated by evaluating the impact of the change in the area-diameter and the density-diameter relationships in the retrieval of cloud properties. We show that changes to these assumptions affect the radar-only and lidar-only retrieval more than the radar-lidar retrieval, although the lidar-only extinction retrieval is only weakly affected. We also show that making use of the molecular lidar signal beyond the cloud as a constraint on optical depth, when ice clouds are sufficiently thin to allow the lidar signal to penetrate them entirely, improves the retrieved extinction. When infrared radiances are available, they provide an extra constraint and allow the extinction-to-backscatter ratio to vary linearly with height instead of being constant, which improves the vertical distribution of retrieved cloud properties

Biomarkers of oxidative stress: methods and measures of oxidative DNA damage (COMET assay) and telomere shortening

Oxidative stress is fast becoming the nutritional and medical buzzword for the twenty-first century. The theoretical importance of oxidative stress in diabetes is highlighted by its potential double impact on metabolic dysfunction on one hand and the vascular system on the other hand. The new concept of oxidative stress, being an important trigger in the onset and progression of diabetes and its complications, emphasizes the need for measurement of markers of oxidation to assess the degree of oxidative stress. While we have been routinely measuring biomarkers in our molecular epidemiology projects, here we discuss the utility of two assays, (a) DNA damage assessment by COMET measurement and (b) telomere length measurement. As DNA damage is efficiently repaired by cellular enzymes, its measurement gives a snapshot view of the level of oxidative stress. The protocol allows for measurement of oxidative DNA damage (FPG-sensitive DNA strand breaks). Telomere length measured by Southern blotting technique allows one to estimate the chronic burden of oxidative stress at the molecular level and is now considered as biomarker of biological aging