RESUMEN
Habitat heterogeneity and complexity associated with variations in climatic conditions are important factors determining the structure of ant communities in different terrestrial ecosystems. The objective of this study was to describe the horizontal and vertical distribution patterns of the ant community associated with three adjacent habitats in a transition area between the Cerrado and Caatinga biomes at the Pandeiros River, state of Minas Gerais, Brazil. We tested the following hypotheses: (1) the richness and composition of ant species and functional group structure changes between different habitats and strata; (2) habitats with higher tree species richness and density support higher ant species richness; and (3) habitats with lower variation in canopy cover support higher ant species richness. Sampling was conducted in three adjacent habitats and at three vertical strata. Ant species richness was significantly different among vertical strata. Ant species composition was different among both habitats and vertical strata and functional group structure was divergent among habitats. Partitioning of the diversity revealed that the diversity for the three components was statistically different from the one expected by the null model; α and ß 2 were higher and ß 1 was lower than the values expected by chance. Tree density and variation in canopy cover negatively affected ant species richness. The occurrence of different species and the changing of functional group structures in different habitats and strata suggest an ecological-evolutionary relationship between ants and their habitats and emphasize the need to implement local conservation strategies in the ecotones between biomes.
Asunto(s)
Distribución Animal , Hormigas , Ecosistema , Animales , Hormigas/clasificación , Biodiversidad , Brasil , ÁrbolesRESUMEN
The aim of this study was to describe the CT scan abnormalities in 15 patients with acute pulmonary coccidioidomycosis. Retrospective analysis of chest CT scans from 15 patients with acute pulmonary coccidioidomycosis was performed. The final diagnosis included the finding of Coccidioides immitis in mycology and/or histopathology, complemented by serology. Two radiologists evaluated the CT scans to study the type, size, profusion and localization of the findings. The final decisions were defined by consensus. CT scans showed multiple bilateral nodules in 13 patients and solitary nodules associated with consolidation in 2 cases. The nodules had ill-defined contours, ranging from 0.5 cm to 3.0 cm in diameter, which were predominant in the lower lobes in 11 cases. Cavitation of nodules was observed in 13 cases and coalescence in 7. Nodule-associated abnormalities were found in 13 cases, comprising interlobular septal thickening (n = 7) and consolidations (n = 6). Other abnormalities included lymph node enlargement (n = 6) and small pleural effusion (n = 2). In conclusion, the main CT finding in patients with acute coccidioidomycosis was that of multiple nodules (0.5-3.0 cm) at the lungs bases; a significant proportion of the remaining cases also showed other abnormalities. A diagnosis of coccidioidomycosis must be considered in patients with multiple lung nodules that are either in, or have recently been transported to, areas of endemic mycosis.
Asunto(s)
Coccidioidomicosis/diagnóstico por imagen , Enfermedades Pulmonares Fúngicas/diagnóstico por imagen , Enfermedad Aguda , Adolescente , Adulto , Niño , Enfermedad Crónica , Coccidioidomicosis/patología , Diagnóstico Diferencial , Femenino , Humanos , Enfermedades Pulmonares Fúngicas/patología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tomografía Computarizada por Rayos XRESUMEN
In the present study we investigated the effect of acute fluoxetine administration on the expression of c-Fos in the rat brain under two different metabolic conditions: fed and fasting states. Wistar male rats, weighing 220+/-30g, received i.p. injections of saline solution or fluoxetine (10mg/kg), and were killed 2 h later. The brains were removed after transcardiac perfusion with phosphate-buffered saline followed by paraformaldehyde, and were then processed for immunohistochemistry. Fos-like immunoreactivity was quantified by a computerized system. Fasted animals faced an 18-h suppression of food intake, while fed groups were submitted to an initial 14-h period of fast followed by a 4-h period in which food was freely available. Both in fasting and fed states, fluoxetine-treated animals presented a significant increase in c-Fos expression in hypothalamic areas, limbic structures, circumventricular areas, and in mesencephalic and rhomboencephalic regions, as compared with saline-treated controls. The quantitative comparison of data obtained from fasted and fed animals showed that fasted rats treated with fluoxetine presented a higher c-Fos expression in the ventromedial hypothalamus and the paraventricular nuclei compared with the fed group, while in fluoxetine-treated fed rats c-Fos expression was higher in the arcuate nuclei, medial amygdala, locus coeruleus and dorsal raphe nuclei, as compared with fasted, fluoxetine-treated animals. These data indicate that the metabolic condition of the animals significantly modifies fluoxetine-induced brain c-Fos expression, suggesting that visceral and behavioral fluoxetine effects may be influenced by the metabolic state of the individual.
Asunto(s)
Encéfalo/efectos de los fármacos , Fluoxetina/administración & dosificación , Privación de Alimentos/fisiología , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/metabolismo , Análisis de Varianza , Animales , Encéfalo/anatomía & histología , Encéfalo/metabolismo , Inmunohistoquímica/métodos , Masculino , Proteínas Proto-Oncogénicas c-fos/genética , Ratas , Ratas Wistar , Inhibidores Selectivos de la Recaptación de Serotonina/administración & dosificaciónRESUMEN
Melanoma tumor growth and progression are highly dependent on adequate blood supply through angiogenesis. Since several genes involved in angiogenesis revealed potential binding sites for the transcription factor Sp1, we have examined the effects of local inoculation of Sp1 decoy oligodeoxynucleotides (ODNs) on the growth of transplanted murine melanoma tumors and the expression of VEGF and TNF-alpha within these tumors. Treatment with Sp1 decoy ODNs, but not their mutated form, led to a significant increase (P=0.041) of the tumor necrotic area, as evaluated morphometrically. Tumor necrosis was associated with a significant decrease of microvascular density (P=0.012) and relative vascular area (P=0.026), as determined by counting CD34-positive vascular structures within the tumor microenvironment of Sp1 decoy ODNs and control ODN-treated tumors. RT-PCR experiments showed a strong decrease in the levels of VEGF188 and VEGF164 isoforms and a moderate decrease of TNF-alpha in Sp1 decoy-treated tumors. Taken together, our results indicate that Sp1 decoy ODNs may inhibit angiogenesis by affecting the gene expression of key players in angiogenesis such as TNF-alpha and VEGF. These findings indicate that Sp1 decoy ODNs may be a potential new therapeutic tool in antiangiogenic therapy.
Asunto(s)
Terapia Genética/métodos , Melanoma/terapia , Neovascularización Patológica/terapia , Oligodesoxirribonucleótidos Antisentido/administración & dosificación , Neoplasias Cutáneas/terapia , Factor de Transcripción Sp1/genética , Animales , Regulación de la Expresión Génica , Melanoma/metabolismo , Melanoma/patología , Ratones , Ratones Endogámicos C57BL , Necrosis , Trasplante de Neoplasias , Neovascularización Patológica/metabolismo , Neovascularización Patológica/patología , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , Factor de Necrosis Tumoral alfa/genética , Factor A de Crecimiento Endotelial Vascular/genéticaRESUMEN
Previous studies have examined the arrangement of regulatory elements along the apolipoprotein B (apoB) promoter region (-3067 to +940) and a promoter fragment extending from nucleotides -150 to +124 has been demonstrated to be essential for transcriptional activation of the apoB gene in hepatic and intestinal cells. It has also been shown that transcriptional activation of apoB requires a synergistic interaction between hepatic nuclear factor-4 (HNF-4) and CCAAT/enhancer-binding protein a (C/EBPa) transcription factors. Here, we have examined the hypothesis that HNF-4 factor binding to DNA may induce a DNA helix bend, thus facilitating the communication with a C/EBPa factor located one helix turn from this HNF-4 factor in the apoB promoter. A gel electrophoretic mobility shift assay using wild type double-stranded oligonucleotides or modified wild type duplex oligonucleotides with 10 nucleotides inserted between HNF-4 and C/EBPa factor motifs showed similar retarded complexes, indicating that HNF-4 and C/EBPa factors interact independently of the distance between binding sites. However, when only one base, a thymidine, was inserted at the -71 position of the apoB promoter, the complex shift was completely abolished. In conclusion, these results regarding the study of the mechanisms involving the interaction between HNF-4 and C/EBPa factors in the apoB promoter suggest that the perfect 5'-CCCTTTGGA-3' motif is needed in order to facilitate the interaction between the two factors.
Asunto(s)
Apolipoproteínas B , Regiones Promotoras Genéticas , Factores de Transcripción , Secuencia de Bases , Oligonucleótidos , Factor de Transcripción AP-1RESUMEN
Previous studies have examined the arrangement of regulatory elements along the apolipoprotein B (apoB) promoter region (-3067 to +940) and a promoter fragment extending from nucleotides -150 to +124 has been demonstrated to be essential for transcriptional activation of the apoB gene in hepatic and intestinal cells. It has also been shown that transcriptional activation of apoB requires a synergistic interaction between hepatic nuclear factor-4 (HNF-4) and CCAAT/enhancer-binding protein alpha (C/EBP alpha) transcription factors. Here, we have examined the hypothesis that HNF-4 factor binding to DNA may induce a DNA helix bend, thus facilitating the communication with a C/EBP alpha factor located one helix turn from this HNF-4 factor in the apoB promoter. A gel electrophoretic mobility shift assay using wild type double-stranded oligonucleotides or modified wild type duplex oligonucleotides with 10 nucleotides inserted between HNF-4 and C/EBP alpha factor motifs showed similar retarded complexes, indicating that HNF-4 and C/EBP alpha factors interact independently of the distance between binding sites. However, when only one base, a thymidine, was inserted at the -71 position of the apoB promoter, the complex shift was completely abolished. In conclusion, these results regarding the study of the mechanisms involving the interaction between HNF-4 and C/EBP alpha factors in the apoB promoter suggest that the perfect 5'-CCCTTTGGA-3' motif is needed in order to facilitate the interaction between the two factors.