39 research outputs found

    Attenuated reovirus displays oncolysis with reduced host toxicity

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    Background: Although the naturally occurring reovirus causes only mild symptoms in humans, it shows considerable potential as an oncolytic agent because of its innate ability to target cancer cells. In immunocompromised hosts, however, wild-type reovirus can target healthy tissues, including heart, liver, pancreas and neural structures. Methods: We characterized an attenuated form of reovirus (AV) derived from a persistently infected cell line through sequence analysis, as well as western blot and in vitro transcription and translation techniques. To examine its pathogenesis and oncolytic potential, AV reovirus was tested on healthy embryonic stem cells, various non-transformed and transformed cell lines, and in severe combined immunodeficiency (SCID) mice with tumour xenografts. Results: Sequence analysis of AV reovirus revealed a premature STOP codon in its sigma 1 attachment protein. Western blot and in vitro translation confirmed the presence of a truncated ?1. In comparison to wild-type reovirus, AV reovirus did not kill healthy stem cells or induce black tail formation in SCID mice. However, it did retain its ability to target cancer cells and reduce tumour size. Conclusion: Despite containing a truncated attachment protein, AV reovirus still preferentially targets cancer cells, and compared with wild-type reovirus it shows reduced toxicity when administered to immunodeficient hosts, suggesting the potential use of AV reovirus in combination cancer therapy

    The multiple facets of drug resistance: one history, different approaches

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    Comparison of the Quality Adjusting of Nonlinear Models for Organs, Carcass and Body Components in Meat-Type (Coturnix Coturnix Coturnix) and Laying-Type (Coturnix Coturnix Japonica) Quail

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    ABSTRACT The objective of this study was to evaluate the adjustment quality of nonlinear models to data organs growth, carcass and body components of meat-type (Coturnix coturnix coturnix) and japanese laying-type (Coturnix coturnix japonica) quail. A total of 1350 quails from one to 42 d old were distributed in a completely randomized design, with five replicates each. To determine the organs growth (gut, heart, liver and gizzard), carcass and body components (wing, thigh and drumstick, back and breast), two quails per repetition were slaughtered weekly. The data were evaluated in function of different nonlinear models (Logistical, Brody, Richards, Von Bertalanffy and Gompertz). All models studied adjusted the data, differing in adjustment quality. Brody model showed the best description of gut length to all treatments. For the data gizzard weight, heart, liver and gut, the models that best adjusted, presenting smaller residual mean square and numbers iterations were Gompertz and Logistical. The Gompertz, Logistic and Von Bertalanffy models were the most adequate to describe the thigh and drumstick growth, back and breast, and Gompertz models and Logistic to describe the wing growth and carcass, showing lesser number of iterations to achieve the convergence of date, as well as low residual mean square and squares sums of the regression residuals. The Gompertz model was the most appropriate to describe the organs growth and body components in meat- and laying-type quail when evaluated in growth phase

    Poultry feed metabolizable energy determination using total or partial excreta collection methods

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    The aim of this work was to compare the efficiency of total (TC) or partial (PC) collection excreta methods to determine metabolizable energy in poultry feeds. A number of 180 12- to 21-day-old broilers were distributed into two treatments of six replicates of 10 birds each. A reference-diet was formulated to supply broiler requirements, and the test-diets consisted of 60% of reference diets and 40% of corn or soybean meal. Celite was added at 1% to the diets as a marker. Excreta and diet samples were analyzed for dry matter, energy, nitrogen, and acid-insoluble ash (AIA). AME of corn determined by partial collection (PC) was higher (3544 kcal/kg) as compared to total collection (TC) (3133 kcal/kg). However, no difference were observed for soybean meal (1797 vs. 1821 kcal/kg) between both methods. Marker recovery rates in the excreta were 101, 111, and 96% for the basal-diet, and the test-diets with corn or soybean meal, respectively. This result indicates the importance of marker recovery rate in the excreta to evaluate feed AME and digestibility

    Comparison of the Quality Adjusting of Nonlinear Models for Organs, Carcass and Body Components in Meat-Type (Coturnix Coturnix Coturnix) and Laying-Type (Coturnix Coturnix Japonica) Quail

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    <div><p>ABSTRACT The objective of this study was to evaluate the adjustment quality of nonlinear models to data organs growth, carcass and body components of meat-type (Coturnix coturnix coturnix) and japanese laying-type (Coturnix coturnix japonica) quail. A total of 1350 quails from one to 42 d old were distributed in a completely randomized design, with five replicates each. To determine the organs growth (gut, heart, liver and gizzard), carcass and body components (wing, thigh and drumstick, back and breast), two quails per repetition were slaughtered weekly. The data were evaluated in function of different nonlinear models (Logistical, Brody, Richards, Von Bertalanffy and Gompertz). All models studied adjusted the data, differing in adjustment quality. Brody model showed the best description of gut length to all treatments. For the data gizzard weight, heart, liver and gut, the models that best adjusted, presenting smaller residual mean square and numbers iterations were Gompertz and Logistical. The Gompertz, Logistic and Von Bertalanffy models were the most adequate to describe the thigh and drumstick growth, back and breast, and Gompertz models and Logistic to describe the wing growth and carcass, showing lesser number of iterations to achieve the convergence of date, as well as low residual mean square and squares sums of the regression residuals. The Gompertz model was the most appropriate to describe the organs growth and body components in meat- and laying-type quail when evaluated in growth phase.</p></div
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