Síndrome de Bardet-Biedl: relato de dois casos Lavinsky, Jacó; Goldhardt, Raquel; Ariente, Samara Keli ...
Arquivos brasileiros de oftalmologia,
10/2003, Letnik:
66, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A síndrome de Bardet-Biedl é doença de herança autossômica recessiva caracterizada por distrofia retiniana, polidactilia, obesidade, retardo mental e hipogenitalismo. Um ou mais dos achados acima que ...caracterizam a síndrome podem estar ausentes, mas a distrofia retiniana é achado consistente. Esta se manifesta clinicamente na infância com progressiva perda visual, causando grave dificuldade visual na adolescência. Os autores descrevem dois casos de síndrome de Bardet-Biedl, os resultados da acuidade visual, biomicroscopia, oftalmoscopia, angiografia, campo visual e eletrorretinograma. Foi realizada revisão bibliográfica com ênfase na identificação dos sinais sistêmicos, envolvimento ocular, testes eletrofisiológicos e avaliação genética.
Silicon (Si) has been recognized as a beneficial element to improve rice (Oryza sativa L.) grain yield. Despite some evidence suggesting that this positive effect is observed when Si is supplied ...along the reproductive growth stage (from panicle initiation to heading), it remains unclear whether its supplementation during distinct growth phases can differentially impact physiological aspects of rice and its yield and the underlying mechanisms. Here, we investigated the effects of additions/removals of Si at different growth stages and their impacts on rice yield components, photosynthetic performance, and expression of genes (Lsi1, Lsi2 and Lsi6) involved in Si distribution within rice shoots. Positive effects of Si on rice production and photosynthesis were manifested when it was specifically supplied during the reproductive growth stage, as demonstrated by: (1) a high crop yield associated with higher grain number and higher 1000-grain weight, whereas the leaf area and whole-plant biomass remained unchanged; (2) an increased sink strength which, in turn, exerted a feed-forward effect on photosynthesis that was coupled with increases in both stomatal conductance and biochemical capacity to fix CO2; (3) higher Si amounts in the developing panicles (and grain husks) in good agreement with a remarkable up-regulation of Lsi6 (and to a lesser extent Lsi1). We suggest that proper levels of Si in these reproductive structures seem to play an as yet unidentified role culminating with higher grain number and size.
Silicon (Si) plays important roles in alleviating various abiotic stresses. In rice (Oryza sativa), arsenic (As) is believed to share the Si transport pathway for entry into roots, and Si has been ...demonstrated to decrease As concentrations. However, the physiological mechanisms through which Si might alleviate As toxicity in plants remain poorly elucidated. We combined detailed gas exchange measurements with chlorophyll fluorescence analysis to examine the effects of Si nutrition on photosynthetic performance in rice plants a wild‐type (WT) cultivar and its lsi1 mutant defective in Si uptake challenged with As (arsenite). As treatment impaired carbon fixation (particularly in the WT genotype) that was unrelated to photochemical or biochemical limitations but, rather, was largely associated with decreased leaf conductance at the stomata and mesophyll levels. Indeed, regardless of the genotypes, in the plants challenged with As, photosynthetic rates correlated strongly with both stomatal (r² = 0.90) and mesophyll (r² = 0.95) conductances, and these conductances were, in turn, linearly correlated with each other. The As‐related impairments to carbon fixation could be considerably reverted by Si in a time‐ and genotype‐dependent manner. In conclusion, we identified Si nutrition as an important target in an attempt to not only decrease As concentrations but also to ameliorate the photosynthetic performance of rice plants challenged with As.
The purpose of this study was to describe clinical, angiographic, and tomo-graphic prognostic factors in central serous chorioretinopathy.
This is a prospective uncontrolled case series. Forty-six ...eyes (43 patients) with clinical and angiographic findings consistent with central serous chorioretinopathy were included. Clinical data regarding age, sex, duration of symptoms, associated conditions, and best-corrected visual acuity (BCVA) were collected at baseline. Optical coherence tomography was performed at baseline, monthly until fluid resolution occurred, and at the end of the follow-up.
Mean follow-up was 22.8 months. Mean baseline and final logarithm of the minimum angle of resolution BCVA were 0.3 and 0.12 (P < 0.0001), respectively. Statistically significant correlations were observed between the baseline BCVA as well as duration of symptoms and final BCVA. Angiographic patterns were not significantly correlated with the visual outcome. Shorter periods of subfoveal fluid during the follow-up were correlated with better visual acuity. Mean foveal thickness after fluid resolution was 178 +/- 22 microm. Both baseline and final BCVA were strongly correlated with the foveal thickness after fluid resolution.
Initial BCVA may be a reliable predictor of the visual outcome in central serous chorioretinopathy. Eyes with worse BCVA may have an increased risk of foveal atrophy. Fluid persistence on optical coherence tomography may be associated with worse visual prognosis.
We analyzed the growth and photosynthetic behavior of Gallesia integrifolia ('pau-d'alho') and Schinus terebinthifolius ('aroeirinha') under shade, seeking to obtain ecophysiological information for ...introducing seedlings of those species in previously established cacao agroforestry systems. Considering that light intensity under the shade of cacao trees varied between 5 and 10% daylight, 5 months old seedlings were exposed to four irradiance levels (25, 17, 10 and 5% daylight) for 92 days. With shade increase both species displayed trends of decrease leaf mass per unit leaf area, leaf area per plant (LA), relative growth rate (RGR) and net assimilation rate (NAR), and increase leaf area ratio (LAR). The mean values of light-saturated net photosynthetic rate (P nmax) in 25 and 5% daylight were 12.8 and 8.0 μmol CO₂ m⁻² s⁻¹ for G. integrifolia and 17.9 and 7.4 μmol CO₂ m⁻² s⁻¹, respectively, for S. terebinthifolius. Based on the measurements of photosynthetic photon flux density and estimated values of photosynthetic saturated irradiance (Is) we concluded that, in all shaded conditions, the leaves of both species were under sub optimal light conditions to reach P nmax. In spite of the lowest P nmax values, RGR and NAR were significantly higher for G. integrifolia in all irradiance levels. Differences in growth rates can be explained by the higher values of LA, LAR and leaf mass ratio (LMR), as well as by the lower values of Is, photosynthetic compensation irradiance and dark respiration rates observed for G. integrifolia. Even though seedlings of G. integrifolia presented higher capacity to adapt under conditions of dense shade, we concluded that both species were under stress conditions induced by shade in light environments below 25% daylight. On a practical point of view it is possible to conclude that seedlings of both species should be introduced in light gaps, formed after the fall of big trees, or in places in which cacao trees are cultivated using large plant spacing.
Background. To describe the standard autofluorescence (FAF), the near infrared autofluorescence (NIA) and optical coherence tomography (OCT) patterns in central serous chorioretinopathy, correlating ...them with fluorescein angiography. Methods. Cross-sectional observational study, in which patients with at least seven months of CSC underwent ophthalmologic examination, fundus photography, FAF, NIA, fluorescein angiography (FA), and spectral-domain OCT. Results. Seventeen eyes of thirteen patients were included. The presentation features were a mottled hyperFAF in the detached area and areas with pigment mottling. NIA images showed areas of hyperNIA similar to FAF and localized areas of hypoNIA, which correlated with the points of leakage in the FA. OCT showed pigment epithelium detachment at the location of these hypoNIA spots. Discussion. FAF showed increased presence of fluorophores in the area of retinal detachment, which is believed to appear secondary to lipofuscin accumulation in the RPE or the presence of debris in the subretinal fluid. NIA has been related to the choroidal melanin content and there were areas of both increased and decreased NIA, which could be explained by damage ahead the retina, basically RPE and choroid. These findings, along with the PEDs found in the areas of hypoNIA, support the notion of a primary choroidal disease in CSC.
Genipa americana L. (Rubiaceae) is a late successional neotropical fruit tree used in riparian forest restoration programs. We analyze the effects of light availability and soil flooding on the ...growth and photosynthetic characteristics of G. americana seedlings under nursery and natural light conditions. Two light levels (full sunlight and shade), and two levels of soil water (flooded and control) were used in the experiment. Flooding induced significant changes in the total seedling biomass (P < 0.01). The differences among water treatments were 70 and 10% at full sunlight and shade, respectively. These changes were explained by alterations in the maximum quantum efficiency of the photosystem 2 (Fv/Fm), light-saturated net photosynthetic rates (A sat) and intrinsic water use efficiency (WUE). G. americana has high physiological plasticity in relation to the light availability and flooding, although significant interactive effects between high light exposure and soil flooding were observed in several photosynthetic and growth variables. The results highlight the importance of the synergistic effects between physical environmental variables on the establishment and growth of G. americana seedlings. In the practical point of view we can indicate that, in degraded riparian forests subjected to soil flooding, seedlings of this species should be planted under partially shaded environments.
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