EFEITO DO TREINAMENTO FÍSICO AERÓBICO EM CORONARIOPATAS SUBMETIDOS A UM PROGRAMA DE REABILITAÇÃO CARDIOVASCULAR

Study Model: Retrospective. Study objectives: Evaluate the effect of aerobic physical training in cardiovascular variables in patients with coronary artery disease participants of a Cardiovascular Rehabilitation Program. Methods: Patients with stable coronary artery disease were included and were analyzed the cardiovascular variables of exercise testing, carried out before and after a minimum period of 12 weeks of aerobic physical training in a Cardiovascular Rehabilitation Program, from February 2002 to July 2005. Results: A significant increment (p <0.0001) of maximal oxygen consumption (VO2 max) was observed after the cardiovascular rehabilitation (30.1 ± 9.5 versus 35.5 ± 8.8 ml/kg/min). The difference of the VO2 max had negative correlation with the initial physical capacity, with greater benefits in patients with smaller initial values of VO2  max. Significant differences were not observed in maximal systolic blood pressure and double product, and a small difference was observed in maximal heart rate. The improvement in ischemic threshold was more pronounced, with an increment of 7.4 ml/kg/min in oxygen consumption, with statistical significance (p < 0.0001) (21.0 ± 6.9 versus 28.4 ± 8.2 ml/kg/min). Conclusions: The cardiovascular rehabilitation improved physical capacity and ischemic threshold in patients participants of a Cardiovascular Rehabilitation Program. The benefit in physical capacity was greater in patients with smaller initial values of maximal oxygen consumption.    Modelo do estudo: Retrospectivo. Objetivos do estudo: Avaliar o efeito do treinamento físico aeróbico nas variáveis cardiovasculares em pacientes coronariopatas participantes do Programa de Reabilitação Cardiovascular. Metodologia: Foram incluídos pacientes portadores de coronariopatia estável e foram avaliadas as variáveis cardiovasculares de testes ergométricos seriados, realizados antes e após um período mínimo de 12 semanas de treinamento físico aeróbico em um Programa de Reabilitação Cardiovascular, de fevereiro de 2002 a julho de 2005. Resultados: Documentou-se incremento significativo (p < 0,0001) do consumo de oxigênio pico (VO2 pico) após a reabilitação cardiovascular (30,1 ± 9,5 versus 35,5 ± 8,8 ml/kg/min). Este delta do VO2 pico apresentou correlação negativa com a capacidade física inicial, com maiores ganhos nos pacientes com menores valores iniciais de VO2 pico. Não foram observadas diferenças significativas na pressão arterial sistólica e no duplo produto pico, e uma diferença de pequena magnitude foi observada na freqüência cardíaca pico. A melhora no limiar isquêmico do miocárdio, avaliada pelo consumo de oxigênio na positivação, foi ainda mais expressiva, com incremento de 7,4 ml/kg/min (p < 0,0001) (21,0 ± 6,9 versus 28,4 ± 8,2 ml/kg/min). Conclusões: A reabilitação cardiovascular melhorou a capacidade física e o limiar isquêmico de pacientes participantes do Programa de Reabilitação Cardiovascular. O benefício na capacidade física foi maior  nos pacientes com menores valores iniciais de consumo de oxigênio pico.   

Impairment of the Plasmodium falciparum Erythrocytic Cycle Induced by Angiotensin Peptides

Plasmodium falciparum causes the most serious complications of malaria and is a public health problem worldwide with over 2 million deaths each year. The erythrocyte invasion mechanisms by Plasmodium sp. have been well described, however the physiological aspects involving host components in this process are still poorly understood. Here, we provide evidence for the role of renin-angiotensin system (RAS) components in reducing erythrocyte invasion by P. falciparum. Angiotensin II (Ang II) reduced erythrocyte invasion in an enriched schizont culture of P. falciparum in a dose-dependent manner. Using mass spectroscopy, we showed that Ang II was metabolized by erythrocytes to Ang IV and Ang-(1–7). Parasite infection decreased Ang-(1–7) and completely abolished Ang IV formation. Similar to Ang II, Ang-(1–7) decreased the level of infection in an A779 (specific antagonist of Ang-(1–7) receptor, MAS)-sensitive manner. 10−7 M PD123319, an AT2 receptor antagonist, partially reversed the effects of Ang-(1–7) and Ang II. However, 10−6 M losartan, an antagonist of the AT1 receptor, had no effect. Gs protein is a crucial player in the Plasmodium falciparum blood cycle and angiotensin peptides can modulate protein kinase A (PKA) activity; 10−8 M Ang II or 10−8 M Ang-(1–7) inhibited this activity in erythrocytes by 60% and this effect was reversed by 10−7 M A779. 10−6 M dibutyryl-cAMP increased the level of infection and 10−7 M PKA inhibitor decreased the level of infection by 30%. These results indicate that the effect of Ang-(1–7) on P. falciparum blood stage involves a MAS-mediated PKA inhibition. Our results indicate a crucial role for Ang II conversion into Ang-(1–7) in controlling the erythrocytic cycle of the malaria parasite, adding new functions to peptides initially described to be involved in the regulation of vascular tonus

Impairment of the Plasmodium falciparum Erythrocytic Cycle Induced by Angiotensin Peptides

Plasmodium falciparum causes the most serious complications of malaria and is a public health problem worldwide with over 2 million deaths each year. The erythrocyte invasion mechanisms by Plasmodium sp. have been well described, however the physiological aspects involving host components in this process are still poorly understood. Here, we provide evidence for the role of renin-angiotensin system (RAS) components in reducing erythrocyte invasion by P. falciparum. Angiotensin II (Ang II) reduced erythrocyte invasion in an enriched schizont culture of P. falciparum in a dose-dependent manner. Using mass spectroscopy, we showed that Ang II was metabolized by erythrocytes to Ang IV and Ang-(1–7). Parasite infection decreased Ang-(1–7) and completely abolished Ang IV formation. Similar to Ang II, Ang-(1–7) decreased the level of infection in an A779 (specific antagonist of Ang-(1–7) receptor, MAS)-sensitive manner. 10−7 M PD123319, an AT2 receptor antagonist, partially reversed the effects of Ang-(1–7) and Ang II. However, 10−6 M losartan, an antagonist of the AT1 receptor, had no effect. Gs protein is a crucial player in the Plasmodium falciparum blood cycle and angiotensin peptides can modulate protein kinase A (PKA) activity; 10−8 M Ang II or 10−8 M Ang-(1–7) inhibited this activity in erythrocytes by 60% and this effect was reversed by 10−7 M A779. 10−6 M dibutyryl-cAMP increased the level of infection and 10−7 M PKA inhibitor decreased the level of infection by 30%. These results indicate that the effect of Ang-(1–7) on P. falciparum blood stage involves a MAS-mediated PKA inhibition. Our results indicate a crucial role for Ang II conversion into Ang-(1–7) in controlling the erythrocytic cycle of the malaria parasite, adding new functions to peptides initially described to be involved in the regulation of vascular tonus

Background matching in the brown shrimp Crangon crangon : adaptive camouflage and behavioural-plasticity

A combination of burrowing behaviour and very efficient background matching makes the brown shrimp Crangon crangon almost invisible to potential predators and preys. This raises questions on how shrimp succeed in concealing themselves in the heterogeneous and dynamic estuarine habitats they inhabit and what type of environmental variables and behavioural factors affect their colour change abilities. Using a series of behavioural experiments, we show that the brown shrimp is capable of repeated fast colour adaptations (20% change in dark pigment cover within one hour) and that its background matching ability is mainly influenced by illumination and sediment colour. Novel insights are provided on the occurrence of non-adaptive (possibly stress) responses to background changes after long-time exposure to a constant background colour or during unfavourable conditions for burying. Shrimp showed high levels of intra- and inter-individual variation, demonstrating a complex balance between behavioural-plasticity and environmental adaptation. As such, the study of crustacean colour changes represents a valuable opportunity to investigate colour adaptations in dynamic habitats and can help us to identify the mayor environmental and behavioural factors influencing the evolution of animal background matching

Linking Oviposition Site Choice to Offspring Fitness in Aedes aegypti: Consequences for Targeted Larval Control of Dengue Vectors

Controlling the mosquito Aedes aegypti, the predominant dengue vector, requires understanding the ecological and behavioral factors that influence population abundance. Females of several mosquito species are able to identify high-quality egg-laying sites, resulting in enhanced offspring development and survival, and ultimately promoting population growth. Here, the authors investigated egg-laying decisions of Ae. aegypti. Paradoxically, they found that larval survival and development were poorest in the containers females most often selected for egg deposition. Thus, egg-laying decisions may contribute to crowding of larvae and play a role in regulating mosquito populations. The authors also tested whether removal of the containers producing the most adult mosquitoes, a World Health Organization-recommended dengue prevention strategy, changes the pattern of how females allocate their eggs. Elimination of the most productive containers led to a more even distribution of eggs in one trial, but not another. These results suggest that behavioral adjustments by egg-laying females may lessen the effectiveness of a common mosquito control tactic. The authors advocate incorporating control strategies that take advantage of the natural egg-laying preferences of this vector species, such as luring egg-laying females to traps or places where their eggs will accumulate, but not develop