ABSTRACT
AIM: To quantify early changes of macular capillary parameters in type 2 diabetic patients using optical coherence tomography angiography(OCTA).METHODS: Retrospective case study. A total of 49 healthy subjects, 52 diabetic patients without retinopathy(noDR)patients, and 43 mild nonproliferative diabetic retinopathy(mNPDR)patients were recruited. Capillary perfusion density, vessel length density(VLD), and average vessel diameter(AVD)were calculated from macular OCTA images(3 mm×3 mm)of the superficial capillary plexus after segmenting large vessels and the deep capillary plexus. Parameters were compared among control subjects, noDR, and mNPDR patients. The area under the receiver operating characteristic curve estimated the abilities of these parameters to detect early changes of retinal microvascular networks.RESULTS: Significant differences were found in the VLD and AVD among the three groups(P<0.001). Compared with the control group, the noDR group had significantly higher AVD(P<0.05). VLD of both layers in patients of mNPDR group was significant decreased compared with that of noDR group(all P<0.01). Deep AVD had a higher area under the curve(AUC)of 0.796 than other parameters to discriminate the noDR group from the healthy group. Deep AVD had the highest AUC of 0.920, followed by that of the deep VLD(AUC=0.899)to discriminate the mNPDR group from the healthy group.CONCLUSIONS: NoDR patients had wider AVD than healthy individuals and longer VLD than mNPDR patients in both layers. When compared with healthy individuals, deep AVD had a stronger ability than other parameters to detect early retinal capillary impairments in noDR patients.
ABSTRACT
Abstract: Pheidole is a genus with wide geographical distribution and diversity, especially in the leaf litter of neotropical forests, where nests are found at the soil-litter interface, in the soil and vegetation, among leaves, seeds, and twigs. Despite the availability of twigs and Pheidole species diversity in the leaf litter, most of this resource is not occupied, which suggests the existence of filters. This study analyzes whether twigs occupied by Pheidole species differ for the outer structure and anatomy of the wood. Twigs were collected from preserved Atlantic Forest fragments in southeastern Brazil. Twigs with Pheidole colonies were measured and the wood anatomy analyzed. We collected 224 twigs with Pheidole colonies, but the analysis was done at 41% due to wood decomposition. Five species were recorded in these twigs, which differ for the outer structure and anatomy of the wood. These results suggest the existence of preference in the occupation of twigs determined by wood structure.
Resumo: Pheidole é um gênero com ampla distribuição geográfica e diversidade, especialmente na serapilheira das florestas da Região Neotropical, onde os ninhos são encontrados na interface solo-serapilheira, solo, vegetação, entre folhas, sementes e galhos. Apesar da disponibilidade de galhos e diversidade de espécies de Pheidole na serapilheira, a maior parte deste recurso não é ocupada, o que sugere a existência de filtros. Neste trabalho analisamos se galhos ocupados por espécies de Pheidole diferem em relação à estrutura externa e anatomia da madeira. A coleta de galhos foi realizada em fragmentos conservados de Mata Atlântica na região Sudeste do Brasil. Os galhos com colônias de Pheidole foram mensurados e a anatomia da madeira analisada. Foram coletados 224 galhos com colônias de Pheidole, mas a análise foi realizada em 41% devido à decomposição da madeira. Nestes galhos foram registradas cinco espécies, que diferem em relação à estrutura externa e anatomia da madeira. Estes resultados sugerem a existência de preferência na ocupação do galho determinada pela estrutura da madeira.