Circadian rhythm dysfunction in glaucoma: A hypothesis     

Girardin Jean-Louis  Ferdinand Zizi  Douglas R Lazzaro  Arthur H Wolintz 《Journal of circadian rhythms》2008,6(1):1-8

The absence of circadian zeitgebers in the social environment causes circadian misalignment, which is often associated with sleep disturbances. Circadian misalignment, defined as a mismatch between the sleep-wake cycle and the timing of the circadian system, can occur either because of inadequate exposure to the light-dark cycle, the most important synchronizer of the circadian system, or reduction in light transmission resulting from ophthalmic diseases (e.g., senile miosis, cataract, diabetic retinopathy, macular degeneration, retinitis pigmentosa, and glaucoma). We propose that glaucoma may be the primary ocular disease that directly compromises photic input to the circadian time-keeping system because of inherent ganglion cell death. Glaucomatous damage to the ganglion cell layer might be particularly harmful to melanopsin. According to histologic and circadian data, a subset of intrinsically photoresponsive retinal ganglion cells, expressing melanopsin and cryptochromes, entrain the endogenous circadian system via transduction of photic input to the thalamus, projecting either to the suprachiasmatic nucleus or the lateral geniculate nucleus. Glaucoma provides a unique opportunity to explore whether in fact light transmission to the circadian system is compromised as a result of ganglion cell loss.  相似文献   

Is land abandonment having an impact on biodiversity? A meta-analytical approach to bird distribution changes in the north-western Mediterranean   总被引：1，自引：0，他引：1  

Clélia Sirami  Lluis Brotons  Ian Burfield  Jean-Louis Martin 《Biological conservation》2008,141(2):450-459

Teasing out how species respond to human-induced environmental changes has become a priority for addressing the challenges posed by the need to conserve biodiversity. Although land abandonment is widespread, the threat it can represent to biodiversity remains poorly understood. To address this issue, we used data from eight long-term studies in a region with widespread land abandonment that has been identified as a biodiversity hotspot, the north-west Mediterranean Basin. We conducted a multi-site analysis of how changes in species occurrence were affected by species’ attributes (habitat preference, habitat breadth, migration strategy and latitudinal distribution). The analysis revealed a nested pattern in the effect of species attributes. Woodland and shrubland species showed the strongest increase, whereas no change in overall occurrence patterns was detected in farmland species. Residents increased significantly, especially those with a northern distribution, whereas migrants decreased significantly, especially farmland species with a narrow habitat breadth. Changes in species occurrence were also related to initial landscape composition, with larger increases in initially woodland or mixed landscapes. Woodland species increased in all landscape types, shrubland species increased only in mixed landscapes, and farmland species decreased more, although not significantly, in farmland landscapes. Our results strongly support the hypothesis that large-scale habitat changes associated mainly with land abandonment are impacting bird community patterns in the Mediterranean region. Negative effects seem to be recorded mostly for migrants in farmland landscapes, suggesting that declines in these species are likely to be caused by a variety of mechanisms interacting with habitat change in the breeding region.  相似文献   

Effects of animal position and number of repeated measurements on selected two-dimensional and M-mode echocardiographic variables in healthy dogs     

Chetboul V  Tidholm A  Nicolle A  Sampedrano CC  Gouni V  Pouchelon JL  Lefebvre HP  Concordet D 《Journal of the American Veterinary Medical Association》2005,227(5):743-747

OBJECTIVE: To evaluate the effects of positioning and number of repeated measurements on intra- and interobserver variability of echocardiographic measurements in dogs. DESIGN: Prospective study. ANIMALS: 4 healthy dogs. PROCEDURE: Each observer performed 24 examinations, separately assessing each dog 6 nonconsecutive times (3 times with the dog in lateral recumbency and 3 with the dog in a standing position). Variables evaluated included M-mode measurements of left ventricular end-diastolic and left ventricular end-systolic diameters, left ventricular free-wall thickness in diastole and systole, interventricular septal thickness in diastole and systole, left ventricular shortening fraction, and 2-dimensional measurements of the left atrial diameter-to-aortic diameter ratio. RESULTS: All coefficients of variation (range, 3.4% to 26.6%) were similar between operators and positions and were < 15% for 27 of 32 values. For both operators, repeatability of the measurements was better for left ventricular end-systolic diameter, left ventricular free-wall thickness in diastole, left ventricular free-wall thickness in systole, and the left atrial diameter-to-aortic diameter in the standing position, and similar for both positions for shortening fraction and left ventricular end-diastolic diameter. No effect of cardiac cycle was observed. CONCLUSIONS AND CLINICAL RELEVANCE: Within-day variability of conventional echocardiography performed with the dog in the standing position was at least as good as that obtained with the dog in lateral recumbency for most measured variables. Single measurements of each variable may be sufficient for trained observers examining dogs that do not have an arrhythmia. The standing position should be used, particularly for stressed or dyspneic dogs.  相似文献   

Assessment of repeatability, reproducibility, and effect of anesthesia on determination of radial and longitudinal left ventricular velocities via tissue Doppler imaging in dogs     

Chetboul V  Athanassiadis N  Carlos C  Nicolle A  Zilberstein L  Pouchelon JL  Lefebvre HP  Concordet D 《American journal of veterinary research》2004,65(7):909-915

OBJECTIVE: To determine left ventricular free wall (LVFW) motions and assess their intra- and interday variability via tissue Doppler imaging (TDI) in healthy awake and anesthetized dogs. ANIMALS: 6 healthy adult Beagles. PROCEDURE: n the first part of the study, 72 TDI examinations (36 radial and 36 longitudinal) were performed by the same observer on 4 days during a 2-week period in all dogs. In the second part, 3 dogs were anesthetized with isoflurane and vecuronium. Two measurements of each TDI parameter were made on 2 consecutive cardiac cycles when ventilation was transiently stopped. The TDI parameters included maximal systolic, early, and late diastolic LVFW velocities. RESULTS: The LVFW velocities were significantly higher in the endocardial than in the epicardial layers and also significantly higher in the basal than in the mid-segments in systole, late diastole, and early diastole. The intraday coefficients of variation (CVs) for systole were 16.4% and 22%, and the interday CV values were 11.2% and 16.4% in the endocardial and epicardial layers, respectively. Isoflurane anesthesia significantly improved the intraday CV but induced a decrease in LVFW velocities, except late diastolic in endocardial layers and early diastolic in epicardial layers. CONCLUSIONS AND CLINICAL RELEVANCE: Left ventricular motion can be adequately quantified in dogs and can provide new noninvasive indices of myocardial function. General anesthesia improved repeatability of the procedure but cannot be recommended because it induces a decrease in myocardial velocities.  相似文献   

Taxonomic and functional characterization of microbial communities in Technosols constructed for remediation of a contaminated industrial wasteland     

Farhan Hafeez  Fabrice Martin-Laurent  Jérémie Béguet  David Bru  Jér?me Cortet  Christophe Schwartz  Jean-Louis Morel  Laurent Philippot 《Journal of Soils and Sediments》2012,12(9):1396-1406

Purpose

The construction of Technosols is an emergent technology based on the assemblage of technogenic materials for ecological reclamation of polluted land and waste recycling. Although this technology is in expansion, knowledge about the microbial communities in Technosols is limited, despite their central role in ecosystem functioning. In this 2-year study, the diversity and the abundance of total and functional microbial communities were characterized in two types of Technosols constructed to reclaim contaminated sites.

Materials and methods

The structure of the microbial community was analyzed by automated ribosomal intergenic spacer analysis fingerprinting in both types of Technosols, and the taxonomic diversity was further assessed by 16S rRNA clone library sequencing. Real-time PCR was used to quantify the abundance of the total bacterial and crenarchaeal community and of the functional guilds involved in N-cycling.

Results and discussion

16S rRNA sequencing showed that Proteobacteria was the main phylum in the Technosols (50?C80?%). The other significant phyla identified were Bacteroidetes, Firmicutes, Choloroflexi, and Actinobacteria. Real-time PCR quantification of the abundance of ammonia oxidizers, nitrate reducing, and denitrifying microbial communities involved in nitrogen cycling revealed that bacterial ammonia oxidizers were more abundant than crenarchaeal ammonia oxidizers. A high spatial variability of the microbial community, which decreased with time, was also observed.

Conclusions

At the phyla and class levels, the composition of the microbial community in constructed Technosols was similar to ??natural?? soils. Both the total bacteria and microbial guilds involved in N-cycling were abundant, but in contrast to most natural soils, bacteria and not crenarchaea were the numerically dominant ammonia oxidizers in both types of Technosols. The decrease with time of the variability in microbial community structure support early pedogenic evolution of recently constructed Technosols.  相似文献   

Genetic diversity of taro (Colocasia esculenta (L.) Schott) in Vanuatu (Oceania): an appraisal of the distribution of allelic diversity (DAD) with SSR markers     

Julie Sardos  Jean-Louis Noyer  Roger Malapa  Sophie Bouchet  Vincent Lebot 《Genetic Resources and Crop Evolution》2012,59(5):805-820

In Vanuatu, an oceanic archipelago located in south-west Pacific, taro (Colocasia esculenta (L.) Schott) is one of the staple crops. An eco-geographical survey of its genetic resources was conducted in ten villages, each located on a different island. A sample of 344 landraces referred as the National Sample (NS) was collected. Its genetic diversity was assessed using nine microsatellites markers and then was compared with an International Core Sample (ICS) that was previously distributed in the ten villages of the study in order to test the geographical distribution of allelic diversity as an effective mean for the on-farm conservation of root crops. The ICS was composed of 41 accessions, including 23 originating from South-East Asia. The molecular dataset revealed in the NS (1) 324 distinct multilocus genotypes, (2) six genetic clusters mainly differentiated by rare alleles, (3) a geographical structure of the genetic resources of taro based, within each village, on the dominance of one or two of these clusters rather that their exclusivity, and (4) an analogy between the patterns of dominant clusters between villages and the past and present social networks. In addition, accessions from the ICS revealed 52 new alleles. Based on these findings, we formulate hypotheses regarding the processes involved in the genetic diversification of taro in Vanuatu. We also discuss the use of this set of microsatellite markers along with the molecular dataset obtained from this study as effective tools to monitor the diversity and evolution of taro in the future.  相似文献   

Self-assembled magnetic matrices for DNA separation chips     

Doyle PS  Bibette J  Bancaud A  Viovy JL 《Science (New York, N.Y.)》2002,295(5563):2237

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Impact of destroying the structure of model gels on volatile release     

Savary G  Sémon E  Meunier JM  Doublier JL  Cayot N 《Journal of agricultural and food chemistry》2007,55(17):7099-7106

The release of a strawberry aroma from different composite gels taken as models of fruit preparations and from a sucrose solution was investigated. The composition of the model systems differed with regard to the gelling agent, either pectin or carrageenan, and to the rigidity of the gel. With the use of atmospheric pressure chemical ionization-mass spectrometry, the release profiles of the aroma compounds were determined under stirring. At the same time, purge and trap measurements were performed to determine the release profiles of the aroma compounds without stirring. The comparison of the patterns obtained using these two complementary methods made it possible to determine how the structure of the matrix, the mechanical treatment, and the properties of the aroma compound affect aroma release. A far greater proportion of the aroma compounds was retained in the fruit preparation systems than in the sucrose solution. The different release profiles could be interpreted in terms of the volatility of the aroma compounds and of their diffusion through the gels.  相似文献   

Inter-Alu PCR like genomic profiling in banana     

Franc-Christophe Baurens  Jean-Louis Noyer  Claire Lanaud  Pierre Jean Laurent Lagoda 《Euphytica》1998,99(2):137-142

Alu sequences are a major repetitive element of the primate genome. To date Alu sequences have seldom been reported in plant genomes. We report here an inter-Alu PCR like genomic profiling in banana using a single primer designed from a human Alu sequence. The different Musa species involved in the complex genome of banana cultivars can thus be discriminated. The use of this technique for monitoring germplasm or genotyping cultivars is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献