Um estudo da influência de alguns fatores sobre a distribuição de frequência de cromatina sexual em populações normais

Orientador: Prof. Dr. Francisco Antônio MarçalloDissertação (mestrado) - Universidade Federal do Paraná, Curso de Pós-Graduação em Genética HumanaInclui referências: p. 37-3

A shorter fixation protocol for transmission electron microscopy: An alternative to spend less time

The performance of a moderately shorter fixation protocol for transmission electron microscopy (TEM) was evaluated by analyzing the cell structure quality after the processing. The relevance of this experimental technique is mainly based on reducting time of the steps of conventional protocols: fixation, washes, dehydration, and epoxy resin infiltration. Two sources of murine cells were used, the peritoneal and mesenteric lymph node cells. A fixation and material processing faster than usual methods can save time and improve results. Samples analysis indicated good preservation of different cell structures and organelles after this protocol

The effect of brown spider venom on endothelial cell morphology and adhesive structures

Spiders of the Loxosceles genus have been responsible for severe clinical cases of envenomation worldwide. Accidents involving brown spiders can cause dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of animals treated by venom have shown subendothelial blebs, vacuoles and endothelial cell membrane degeneration of blood vessel walls, as well as fibrin and thrombus formation. the mechanisms by which the venom causes these disorders are poorly understood. in this work, with an endothelial cell line derived from rabbit aorta, we were able to demonstrate that venom binds to the cell surface and the extracellular matrix. Moreover, we observed that the venom also induced morphological alterations, such as cell retraction, homophilic disadhesion and an increasing in filopodia projections. We also demonstrated that toxins present in the venom disorganized focal adhesion points and actin microfilaments of endothelial cells. Nevertheless, endothelial cell viability showed no alterations compared to controls. Additionally, venom treatment changed the fibronectin matrix profile synthesized by these cells as well as cell adhesion to fibronectin. These results suggest that the deleterious effects of venom on blood vessel walls could be a consequence of the direct effect on the endothelial cell surface and adhesive structures involved in blood vessel stability. These effects indirectly lead to leukocyte and platelet activation, disseminated intravascular coagulation and an increase in vessel permeability. (c) 2006 Elsevier B.V. All rights reserved.Univ Fed Parana, Dept Cell Biol, BR-81531990 Curitiba, Parana, BrazilUNIFESP, Dept Med, Med Clin Discipline, São Paulo, BrazilCatholic Univ Parana, Hlth & Biol Sci Inst, Curitiba, Parana, BrazilUNIFESP, Dept Biochem, São Paulo, BrazilUNIFESP, Dept Med, Med Clin Discipline, São Paulo, BrazilUNIFESP, Dept Biochem, São Paulo, BrazilWeb of Scienc

Blunted feelings: Alexithymia is associated with a diminished neural response to speech prosody

How we perceive emotional signals from our environment depends on our personality. Alexithymia, a personality trait characterized by difficulties in emotion regulation has been linked to aberrant brain activity for visual emotional processing. Whether alexithymia also affects the brain's perception of emotional speech prosody is currently unknown. We used functional magnetic resonance imaging to investigate the impact of alexithymia on hemodynamic activity of three a priori regions of the prosody network: the superior temporal gyrus (STG), the inferior frontal gyrus and the amygdala. Twenty-two subjects performed an explicit task (emotional prosody categorization) and an implicit task (metrical stress evaluation) on the same prosodic stimuli. Irrespective of task, alexithymia was associated with a blunted response of the right STG and the bilateral amygdalae to angry, surprised and neutral prosody. Individuals with difficulty describing feelings deactivated the left STG and the bilateral amygdalae to a lesser extent in response to angry compared with neutral prosody, suggesting that they perceived angry prosody as relatively more salient than neutral prosody. In conclusion, alexithymia may be associated with a generally blunted neural response to speech prosody. Such restricted prosodic processing may contribute to problems in social communication associated with this personality trait