Substituição valvar cardíaca em ovinos – Descrição da técnica operatória e análise dos resultados

To evaluate the technical proceduresof a research protocol with tissue-engineered heartvalves in sheep, the surgical techniques for pulmonic,aortic and mitral valve replacement and the outcomeof 58 heart valve surgeries was analyzed. Thesheeps (age 18 ± 7 weeks and body weigh 30 ± 9.9kg) were implanted with valve bioprosthesis understandard protocols. Forty animals received pulmonicvalve prosthesis, fourteen animals received aorticprosthesis and four animals were implanted withmitral prosthesis. The fourth intercostal space wereconsidered the best for all operative techniques.The cardiopulmonary bypass (CPB) method throughcanulation of descending aorta and right atrial wereconsidered fast and secure. The CPB time of pulmonicvalve replacement was 34 ± 14 minutes and mortalityrate was 7,5%. The CPB time of subcoronarian aorticvalve implantation was 119 ± 5 minutes and themortality rate was 57%. In mitral substitution the CPBtime was 74 ± 22 minutes and mortality was 50%.The technique of pulmonic valve replacement wasvery efficient, however the mortality rate of both aorticand mitral valve surgery, associated with the highlysurgical technical complexity and elevated CPB time,require technical refinements to improve exploitationof the animals on the left side cardiac surgeries.Visando avaliar um protocolo experimentalde pesquisa com próteses valvares cardíacas emovinos, as técnicas cirúrgicas de substituição valvarpulmonar, aórtica e mitral de 58 cirurgias cardíacas foramanalisadas. Através de procedimentos padronizadosos ovinos (idade 18 ± 7 semanas e o peso 30 ± 9.9kg) foram submetidos ao implante de próteses valvaresbiológicas. Quarenta animais receberam prótesesvalvares pulmonares, 14 animais receberam prótesesaórticas e quatro animais receberam próteses mitrais.O quarto espaço inter-costal foi considerado de eleiçãopara realização das três técnicas operatórias avaliadas.O método de circulação extracorpórea (CPB)por canulação da aorta descendente e do átrio direitofoi considerado rápido e seguro. O tempo de CPB durantea substituição valvar pulmonar foi de 34 ± 14minutos e a mortalidade 7,5%. A substituição valvaraórtica, com implante subcoronariano, teve tempo deCPB 119 ± 5 minutos e mortalidade de 57%. Durantea substituição valvar mitral o tempo de CPB foi 74 ±22 minutos e mortalidade 50%. A técnica de implantevalvar pulmonar foi muito eficiente, entretanto a altamortalidade das técnicas de implante valvar aórtico emitral, associadas à maior complexidade cirúrgica eelevado tempo de CPB, faz necessário refinamentostécnicos para melhorar o aproveitamento dos animaisnas cirurgias das valvas cardíadas esquerdas

Radiação fotossinteticamente ativa incidente e Refletida acima e abaixo do dossel de floresta de Mata Atlântica em Coruripe, Alagoas

The study of solar radiation is important to understand the several physical, chemical and biological processes that occur in the biosphere, particularly in the forest. The objective of this study has been to evaluate the temporal evolution of incident and reflected Photosynthetic Active Radiation (PAR) above and below the canopy of the Mata Atlantica forest. The study has been conducted in a Private Reserve Natural Heritage, located in the Coruripe city, Alagoas, during the period from October 2009 to September 2010, based on the PAR (2, 13, 26 m) observations obtained at the micrometeorological station, installed on a 24 meters high tower (10° 17' 36"S, 36° 17' 24"W, 160 m asl). According to the results the incident and reflected PAR outside (PAR↓_Ext and PAR↑_Ext) and inside (PAR↑_Spf) forest follow the seasonality imposed by the apparent motion of the Sun. The higher PAR values occur during the dry season, exceeding 600 and 12 W m-2, and during the wet season these averages was less than 300 and 8.0 W m-2, influenced by cloudiness. At the beginning and ending of sunlight time PAR↑_Spf values near zero were measured. The opposite measurements of about 14 W m-2, around 12 h (November and December) were observed

Measuring the strength of interaction between the Ebola fusion peptide and lipid rafts: implications for membrane fusion and virus infection.

The Ebola fusion peptide (EBO₁₆) is a hydrophobic domain that belongs to the GP2 membrane fusion protein of the Ebola virus. It adopts a helical structure in the presence of mimetic membranes that is stabilized by the presence of an aromatic-aromatic interaction established by Trp8 and Phe12. In spite of its infectious cycle becoming better understood recently, several steps still remain unclear, a lacuna that makes it difficult to develop strategies to block infection. In order to gain insight into the mechanism of membrane fusion, we probed the structure, function and energetics of EBO₁₆ and its mutant W8A, in the absence or presence of different lipid membranes, including isolated domain-resistant membranes (DRM), a good experimental model for lipid rafts. The depletion of cholesterol from living mammalian cells reduced the ability of EBO₁₆ to induce lipid mixing. On the other hand, EBO₁₆ was structurally sensitive to interaction with lipid rafts (DRMs), but the same was not observed for W8A mutant. In agreement with these data, W8A showed a poor ability to promote membrane aggregation in comparison to EBO₁₆. Single molecule AFM experiments showed a high affinity force pattern for the interaction of EBO₁₆ and DRM, which seems to be a complex energetic event as observed by the calorimetric profile. Our study is the first to show a strong correlation between the initial step of Ebola virus infection and cholesterol, thus providing a rationale for Ebola virus proteins being co-localized with lipid-raft domains. In all, the results show how small fusion peptide sequences have evolved to adopt highly specific and strong interactions with membrane domains. Such features suggest these processes are excellent targets for therapeutic and vaccine approaches to viral diseases

Measuring the Strength of Interaction between the Ebola Fusion Peptide and Lipid Rafts: Implications for Membrane Fusion and Virus Infection

The Ebola fusion peptide (EBO16) is a hydrophobic domain that belongs to the GP2 membrane fusion protein of the Ebola virus. It adopts a helical structure in the presence of mimetic membranes that is stabilized by the presence of an aromaticaromatic interaction established by Trp8 and Phe12. In spite of its infectious cycle becoming better understood recently, several steps still remain unclear, a lacuna that makes it difficult to develop strategies to block infection. In order to gain insight into the mechanism of membrane fusion, we probed the structure, function and energetics of EBO16 and its mutant W8A, in the absence or presence of different lipid membranes, including isolated domain-resistant membranes (DRM), a good experimental model for lipid rafts. The depletion of cholesterol from living mammalian cells reduced the ability of EBO16 to induce lipid mixing. On the other hand, EBO16 was structurally sensitive to interaction with lipid rafts (DRMs), but the same was not observed for W8A mutant. In agreement with these data, W8A showed a poor ability to promote membrane aggregation in comparison to EBO16. Single molecule AFM experiments showed a high affinity force pattern for the interaction of EBO16 and DRM, which seems to be a complex energetic event as observed by the calorimetric profile. Our study is the first to show a strong correlation between the initial step of Ebola virus infection and cholesterol, thus providin