Caracterização reológica e microstrutural de emulsões água em óleo para uso alimentar

As emulsões inversas água/óleo são sistemas multifásicos complexos, constituídos por uma fase líquida aquosa dispersa numa fase lipídica (contínua), e cristais de gordura para estabilizar a fase dispersa. O mimetismo lipídico nestas emulsões advém da estabilização através do controlo da cinética da cristalização das gorduras [1]. A natureza e a morfologia das fases formadas estão correlacionadas com as propriedades mecânicas e reológicas destes sistemas. Foram estudadas cinco emulsões inversas a/o com diferentes formulações, utilizando diferentes técnicas experimentais: espectrometria mecânica (ensaios reológicos), microscopia óptica (visualização e registo de ensaios reológicos) [2], avaliação instrumental e sensorial de cor e textura. Os ensaios reológicos incluíram ensaios de relaxação de tensões e ensaios dinâmicos, para determinação experimental das funções materiais das emulsões. A microestrutura e a composição, o tamanho de gota e a distribuição de tamanhos de gota das emulsões inversas foram analisadas e medidas por microscopia óptica e análise de imagem. A visualização de escoamentos foi efectuada utilizando uma célula óptica de torção acoplada a um microscópio óptico e a uma câmara digital para observação em tempo real das alterações de textura causadas por deformações ou velocidades de deformação. Foi também efectuada avaliação sensorial e instrumental (cor e textura) das cinco emulsões inversas. A interpretação dos resultados experimentais dos ensaios reológicos foi feita com base no modelo de Palierne [3], considerando um modelo da emulsão inversa constituída por uma fase lipídica contínua, modificada pela presença da rede de cristais lipídicos, e dois tipos de inclusões da fase aquosa: inclusões com uma interface lípido-água sem cristais lipídicos, e inclusões com a interface modificada pela rede de cristais lipídicos. O ajuste efectuado às funções materiais reológicas mostrou que o modelo utilizado consegue descrever, com boa aproximação, os resultados experimentais obtidos. A caracterização reológica da resposta da emulsão a diferentes histórias da deformação foi complementada com a observação em tempo real das alterações de textura ocorridas em cada um dos ensaios referidos, utilizando uma câmara digital. Por utilização da análise de componentes principais, verificou-se que a avaliação sensorial e a avaliação instrumental são correlacionáveis, e que essas correlações podem ser analisadas em termos das constantes materiais reológicas medidas experimentalmente. REFERÊNCIAS: [1] McClements, D., Critical Reviews in Food Science and Nutrition, 2007, 47, 611–649. [2] Bower et al., Rheol Acta, 1999, 38, 145-159. [3] Palierne, J. F., Rheol Acta, 1990, 29, 204-214. Química Agro

A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge

The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine viru

Caracterização Reológica e Óptica de Margarinas

As margarinas são sistemas multifásicos complexos, constituídos por uma fase líquida aquosa dispersa numa fase líquida lipídica contínua, e cristais de gordura para estabilizar a fase dispersa. O mimetismo lipídico nestas emulsões advém da estabilização através do controlo da cinética da cristalização das gorduras. A natureza e morfologia das fases formadas estão correlacionadas com as propriedades mecânicas e reológicas destes sistemas. Conclusões Microscopia óptica: a emulsão B apresenta microestrutura muito diferente das outras emulsões e a emulsão C apresenta tamanho de gota de água maior do que as outras emulsões. O escoamento altera a microstrutura da emulsão, em função das condições de escoamento consideradas. Ensaios dinâmicos: para qualquer das emulsões, a componente elástica G, predomina sobre a componente dissipativa G”, naquela gama de w (gel like). Para todas as emulsões a viscosidade h* depende da frequência w, sob a forma de uma lei de potência, o que indicia comportamento não-newtoniano (reofluidificante). Ensaios transitórios: G(t) exibe um patamar para tempos curtos (gel-like); a viscosidade dependente do tempo h(t) varia com o tempo segundo uma lei de potência. É possível comparar os resultados obtidos com as previsões dos modelos de Palierne e de Pal

Peritoneal fluid modulates the sperm acrosomal exocytosis induced by N-acetylglucosaminyl neoglycoprotein

The effect of peritoneal fluid (PF) on the human sperm acrosome reaction (AR) was tested. Sperm was pre-incubated with PF and the AR was induced by calcium ionophore A23187 and a neoglycoprotein bearing N-acetylglycosamine residues (NGP). The AR induced by calcium ionophore was inhibited 40% by PF from controls (PFc) and 50% by PF from the endometriosis (PFe) group, but not by PF from infertile patients without endometriosis (PFi). No significant differences were found in the spontaneous AR. When the AR was induced by NGP, pre-incubation with PFc reduced (60%) the percentage of AR, while PFe and PFi caused no significant differences. The average rates of acrosome reactions obtained in control, NGP- and ionophore-treated sperm showed that NGP-induced exocytosis differed significantly between the PFc (11%) and PFe/PFi groups (17%), and the ionophore-induced AR was higher for PFi (33%) than PFc/PFe (25%). The incidence of the NGP-induced AR was reduced in the first hour of pre-incubation with PFc and remained nearly constant throughout 4 h of incubation. The present data indicate that PF possesses a protective factor which prevents premature AR.Hospital de Clínicas de Porto AlegreUniversidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

1004-57 Regional Left Ventricular Function by Intraventricular Ultrasound in Patients with Myocardial Infarction

Regional left ventricular (LV) dysfunction induced by ischemia/infarction is accompanied by increased end-systolic stress because the ischemic LV wall is unable to generate enough tension to contribute effectively to systole. To explore the possibility of assessing regional LV dysfunction as changes in LV wall stress we performed intraventricular echocardiography in 10 patients with a 6.2 french/12.5MHZ catheter at the time of cardiac catheterization. Cross-sectional images obtained at the level of the papillary muscles were analyzed by computer aided system to assess left ventricular wall thickness and radius of curvature (RC) in 16 equi-angular segments. End-systolic segmental endocardial radius of curvature divided by LV wall thickness obtained as segment area divided by the average of endo and epicardial arc lengths was utilized as an index of regional LV performance proportional to segmental LV wall stress. Percent wall thickening (WT%) was reduced (20.7±14.5%) in the territory perfused by the stenosed artery determined at catheterization, when compared with WT% obtained from territory perfused by normal coronaries (34.4±15.8%, p<0.05). In addition, systolic wall thickening was inversely related to the ratio of RC to WT at end-systole (r=0.75, %WT=65.5 – 21.4 (RCIWT), p<0.05) reflecting regional systolic dysfunction with increased circumferential end-systolic wall stress in those regions. In conclusion, intraventricular echocardiography correctly detects regional left ventricular dysfunction and its geometric consequences to local LV performance induced by ischemic myocardial damage. This technique may play an important role in monitoring myocardial injury by ischemia during invasive interventional procedures

Effect of breed on meat quality and global acceptance of native lambs and their crosses

International projections point to the growth in global production of sheep meat, mainly from developing countries. However, the exigencies of consumers on characterization of production systems, nutritional information, and sensorial analysis to target the preferences must be answered. The aim of this study was to characterize the meat quality and the global acceptance of Brazilian native ovine breeds and their crosses, and discuss these aspects on the current basis of human health and wellbeing. Three native breeds (Morada Nova, Rabo Largo, and Santa Inês) that were managed in semi-intensive systems and raised in semi-arid Brazilian regions were used. Chemical composition and fatty acid analysis, sensory evaluation and health indices were accessed. The combined effects of breed, sex and breed by sex interaction produced differentiation in meat fatty acid (FA) profiles. The cholesterol contents ranged between 51 and 59.1 mg/100 g. The Morada Nova lambs showed the lowest lipid content (1.93%). The Morada Nova x Rabo Largo crossbreed breed has the potential to increase the content of conjugated linoleic acid. The high content of α-linolenic acid, which is considered hypocholesterolemic, was responsible for better health indices. The moderate acceptability obtained in sensory traits is compatible with the requirements of the consumer market. The combination of nutritional and sensory traits associated with human health and wellbeing that is presented by these native ovine breeds qualifies them as a good choice of red meat to be included in a larger proportion in human food. Keywords: fatty acids, healthier meat, semi-arid region, shee

LV Mass Assessed by Echocardiography and CMR, Cardiovascular Outcomes, and Medical Practice

The authors investigated 3 important areas related to the clinical use of left ventricular mass (LVM): accuracy of assessments by echocardiography and cardiac magnetic resonance (CMR), the ability to predict cardiovascular outcomes, and the comparative value of different indexing methods. The recommended formula for echocardiographic estimation of LVM uses linear measurements and is based on the assumption of the left ventricle (LV) as a prolate ellipsoid of revolution. CMR permits a modeling of the LV free of cardiac geometric assumptions or acoustic window dependency, showing better accuracy and reproducibility. However, echocardiography has lower cost, easier availability, and better tolerability. From the MEDLINE database, 26 longitudinal echocardiographic studies and 5 CMR studies investigating LVM or LV hypertrophy as predictors of death or major cardiovascular outcomes were identified. LVM and LV hypertrophy were reliable cardiovascular risk predictors using both modalities. However, no study directly compared the methods for the ability to predict events, agreement in hypertrophy classification, or performance in cardiovascular risk reclassification. Indexing LVM to body surface area was the earliest normalization process used, but it seems to underestimate the prevalence of hypertrophy in obese and overweight subjects. Dividing LVM by height to the allometric power of 1.7 or 2.7 is the most promising normalization method in terms of practicality and usefulness from a clinical and scientific standpoint for scaling myocardial mass to body size. The measurement of LVM, calculation of LVM index, and classification for LV hypertrophy should be standardized by scientific societies across measurement techniques and adopted by clinicians in risk stratification and therapeutic decision making