51 research outputs found
Bilateral Diffuse Uveal Melanocytic Proliferation Presenting as Small Choroidal Melanoma
Purpose. To describe a patient with Bilateral Diffuse Uveal Proliferation who presented initially with a clinical picture consistent with choroidal melanoma. Methods. Presentation of a clinical case with fundus photos, fluorescein angiography, and optical coherence tomography. Results. A 70-year-old Caucasian male with history of esophageal cancer presented with an asymptomatic pigmented choroidal lesion in his left eye initially diagnosed as choroidal nevus. This lesion enlarged over the course of a year and developed orange pigment and increased thickness. A metastatic workup was negative, and a radioactive iodine plaque was placed on the left eye. Over the next six months, the visual acuity in his left eye decreased. His clinical picture was consistent with unilateral Diffuse Uveal Proliferation. A recurrence of his esophageal carcinoma with metastasis was discovered and palliative chemotherapy was initiated. Although his visual acuity improved in the left eye, similar pigmentary changes developed in the right fundus. His visual acuity in both eyes gradually decreased to 20/200 until his death a year later. Conclusion. BDUMP should always be considered in the differential diagnosis of patients with pigmented fundus lesions and a history of nonocular tumors
Pollination and dispersal trait spectra recover faster than the growth form spectrum during spontaneous succession in sandy oldâfields
Question: Spontaneous succession is the most natural and costâeffective solution for grassland restoration. However, little is known about the time required for the recovery of grassland functionality, i.e., for the recovery of reproductive and vegetative processes typical of pristine grasslands. Since these processes operate at different scales, we addressed the question: do reproductive and vegetative processes require different recovery times during spontaneous succession?
Location: KiskunsĂĄg sand region (Central Hungary).
Methods: As combinations of plant traits can be used to highlight general patterns in ecological processes, we compared reproductive (pollinationâ and dispersalârelated) and vegetative (growth form) traits between recovered grasslands of different age (<10 years old; 10â20 years old; 20â40 years old) and pristine grasslands.
Results: During spontaneous succession, the reproductive trait spectra became similar to those of pristine grasslands earlier than the vegetative ones. In arable land abandoned for 10 years, pollinationâ and dispersalârelated trait spectra did not show significant difference to those of pristine grasslands; anemophily and anemochory were the prevailing strategies. Contrarily, significant differences in the growth form spectrum could be observed even after 40 years of abandonment; in recovered grasslands erect leafy species prevailed, while the fraction of dwarf shrubs and tussockâforming species was significantly lower than in pristine grasslands.
Conclusions: The recovery of the ecological processes of pristine grasslands might require different amounts of time, depending on the spatial scale at which they operate. The reproductive trait spectra recovered earlier than the vegetative one, since reproductive attributes first determine plant species sorting at the regional level towards their respective habitats. The recovery of the vegetative trait spectrum needs more time as vegetativeâbased interactions operate on a smaller spatial scale. Thus, vegetative traits might be more effective in the longâterm assessment of restoration success than the reproductive ones
High lifetime inbreeding depression counteracts the reproductive assurance benefit of selfing in a mass-flowering shrub
N:Si:P atomic ratio in the Santa Cruz Channel, ItamaracĂĄ-PE (Northeast Brazil): a nyctemeral variation
Genotypic structure in clonal Rhododendron ferrugineum L-(Ericaceae) populations: origin and maintenance
International audienceGenotypic structure of a closed population of the clonal ericaceous shrub Rhododendron ferrugineum is examined in the light of two independent studies previously conducted on this species. In the first study, spatial distribution of genotypes in the closed population was inferred from the amplified fragment length polymorphism (AFLP) procedure. Age of clones was estimated using their spatial extent and the annual growth rate of shoots. In the second study, ramet demography was studied in the three most representative stages of shrub invasion on two different sites, including the site where the population investigated by AFLP grew. The demographic data recorded were the area occupied by ramets and ramet age, and from this information the developmental pattern of Rhododendron populations was determined. Additional data such as genet density and distance between genets were calculated. These two sources of information allow us to propose that all or most of the clones detected in the closed population established at the early successional stage, and that the present genotypic structure was established several hundred years ago, long before the population reached total closure. Hypotheses concerning the future development of this genotypic structure are discussed
Nestling sex ratios in a population of Bluethroats Luscinia svecica inferred from AFLP (TM) analysis
Times Cited: 13International audienceWe studied the sex ratio of Bluethroat Luscinia svecica broods using AFLPs. Our aim was to test whether there is a bias towards males that could be explained by sexual selection thee-tries, or conversely, a bias towards females that could help explain the female-biased sex ratio among juveniles observed at a wintering site. The AFLP technique was reliable in sexing the nestlings from even small initial DNA quantities. Given the large number of polymorphic markers that can be obtained for each primer combination, the probability of detecting a W-chromosome-linked fragment is reasonably high. As a consequence, this method could be used in other species far sex-ratio studies and for other genetic purposes. Among 246 nestlings. we found an overall proportion of males of 50.8% at hatching and the sex-ratio variation using broods as independent units was not significantly different from expectation under a binomial distribution. None of the parental and environmental variables tested changed significantly the deviance to the model. Thus, sex determination in the Bluethroat seems to match the classical Mendelian model of a 1:1 sex ratio and cannot explain the biased sex ratio towards juvenile females found at the wintering site
Complementarity in mineral nitrogen use among dominant plant species in a subalpine community
Breeding system in an alpine species: Rhododendron ferrugineum L (Ericaceae) in the French northern Alps
International audienceThe breeding system of the alpine shrub Rhododendron ferrugineum was studied at two sites of a population (site L and site H) in the French Alps. The aims were to estimate the degree of selfing and (or) outcrossing and to determine if floral traits (including floral morphology, pollen to ovule ratio, stigma receptivity) may be related to the breeding system of the shrub. First, floral traits (corolla length and anther, and style heights) were measured, the number of pollen tetrads and ovules were counted, and the date of stigma receptivity and anther dehiscence were recorded. Second, five pollinations treatments (unmanipulated flowers, natural selfing, hand selfing, natural outcrossing, and hand outcrossing) were performed on 35 randomly chosen individuals in each site, and after each treatment the number of seeds per fruit was recorded. The results demonstrate that Rhododendron ferrugineum is self-compatible (self-compatibility index = 0.95 and 0.97; auto-fertility index = 0.92 and 0.98; selfing rate = 0.24 and 0.11 at sites L and H, respectively). Indices values are not significantly different between the two sites and facultatively xenogamous (pollen to ovule ratio = 669.5 +/- 280.5 and 845.2 +/- 246.9 at sites L and H, respectively)
Dynamics of genotypic structure in clonal Rhododendron ferrugineum (Ericaceae) populations
Times Cited: 25International audienceTwo populations of Rhododendron ferrugineum growing at subalpine level in the Pyrenees (France) were studied in two sites (Bethmale and Mourtis). Identification and delimitation of genets were inferred from amplified fragment length polymorphism (AFLP) markers, along a closure gradient (from meadow to more closed heath) in each site. Surface and age of genets, genotypic diversity (Simpson's index D), 'proportion distinguishable' genotypes and genetic relationships between genets were then estimated. Amplification of the 312 DNA samples with three selective primer pairs gave a mean of 98 detectable peaks (i.e. bands) per sample, with size ranging from 60 to 300 bp. In total 60% (Bethmale) and 70% (Mourtis) of the peaks were polymorphic, and a total of 31 and 23 multilocus genotypes were identified, in Bethmale and Mourtis, respectively. We inferred that pioneer genotypes began arriving 110 years ago mainly over a 40-year period in the Mourtis meadow and began about 130 years ago over a 100-year period in the Bethmale meadow After this pioneer stage, populations extended vegetatively. Two different patterns of genotypic dynamics can be identified. At Bethmale, population closure could have led to a dramatic loss of genets and to the selection of highly genetically related genotypes. In contrast, at Mourtis, genotypic diversity and genet density did not change fundamentally along the closure gradient. However the range of genetic diversity diminished from the open to the closed situation, suggesting that thinning could have occurred in the past
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