Cablegation: III. Field Assessment of Performance

LOW rates into and out of furrows were monitored as a cablegation system irrigated a field. The resulting data were used to calculate furrow intake rates as a function of time. The initial supply rates to the furrows were within ± 13 percent of the designed flow rates. Seventy-eight percent of the variation was associated with deviations of the pipe elevation from the design grade. The computer model of this system predicts that deviations in flow rates resulting from elevation deviations will decrease as grade becomes steeper than the 0.28 percent used in this study. Seventy-three percent of the water applied to the field infiltrated. Intake opportunity times averaged 11.0 h at the top end and 8.3 h at the bottom. The furrow intake rate, Ir, was related to the average intake opportunity time, T, by the equation Ir = 48.6 + 214/T. From these data it can be calculated that water applications at the bottom of the field averaged 84 percent of the application at the top end. Runoff rate was relatively constant and total runoff was only about half of that which would have occurred under fixed set surface irrigation. Variability of furrow infiltration rates was high and 10 percent reduction in furrow supply rates would have resulted in water not reaching the ends of some furrows. In general, the cablegation system provides more uniform water application than is normally achieved with other surface irrigation systems. The automatic cutback in supply reduces runoff and the runoff is more easily reused because of its steady flow

Interaction of inflammatory cytokines and erythropoeitin in iron metabolism and erythropoiesis in anaemia of chronic disease

In chronic inflammatory conditions increased endogenous release of specific cytokines (TNFα, IL-1, IL-6, IFNγ and others) is presumed. It has been shown that those of monocyte lineage play a key role in cytokine expression and synthesis. This may be associated with changes in iron metabolism and impaired erythropoiesis and may lead to development of anaemia in patients with rheumatoid arthritis. Firstly, increased synthesis of acute phase proteins, like ferritin, during chronic inflammation is proposed as the way by which the toxic effect of iron and thereby the synthesis of free oxy-radicals causing the damage on the affected joints, may be reduced. This is associated with a shift of iron towards the mononuclear phagocyte system which may participate in the development of anaemia of chronic disease. Secondly, an inhibitory action of inflammatory cytokines (TNFα, IL-1), on proliferation and differentiation of erythroid progenitors as well as on synthesis of erythropoietin has been shown, thereby also contributing to anaemia. Finally, chronic inflammation causes multiple, complex disturbances in the delicate physiologic equilibrium of interaction between cytokines and cells (erythroid progenitors, cells of mononuclear phagocyte system and erythropoietin producing cells) leading to development of anaemia of chronic disease (Fig. 1)

Cablegation: III. Field Assessment of Performance

LOW rates into and out of furrows were monitored as a cablegation system irrigated a field. The resulting data were used to calculate furrow intake rates as a function of time. The initial supply rates to the furrows were within ± 13 percent of the designed flow rates. Seventy-eight percent of the variation was associated with deviations of the pipe elevation from the design grade. The computer model of this system predicts that deviations in flow rates resulting from elevation deviations will decrease as grade becomes steeper than the 0.28 percent used in this study. Seventy-three percent of the water applied to the field infiltrated. Intake opportunity times averaged 11.0 h at the top end and 8.3 h at the bottom. The furrow intake rate, Ir, was related to the average intake opportunity time, T, by the equation Ir = 48.6 + 214/T. From these data it can be calculated that water applications at the bottom of the field averaged 84 percent of the application at the top end. Runoff rate was relatively constant and total runoff was only about half of that which would have occurred under fixed set surface irrigation. Variability of furrow infiltration rates was high and 10 percent reduction in furrow supply rates would have resulted in water not reaching the ends of some furrows. In general, the cablegation system provides more uniform water application than is normally achieved with other surface irrigation systems. The automatic cutback in supply reduces runoff and the runoff is more easily reused because of its steady flow

Experimentally induced intravaginal Tritrichomonas foetus infection in a mouse model Infecção experimental intravaginal com Tritricho-monas foetus em modelo camundongo

The interest to develop research on the host-parasite relationship in bovine tritrichomonosis has accomplished the use of experimental models alternative to cattle. The BALB/c mouse became the most appropriate species susceptible to vaginal Tritrichomonas foetus infection requiring previous estrogenization. For the need of an experimental model without persistent estrogenization and with normal estrous cycles, the establishment and persistence of vaginal infection on BALB/c mouse with different concentrations of T. foetus in two experimental groups was evaluated. Group A was treated with 5mg of b-estradiol 3-benzoate to synchronize the estrous, 48 hours before the T. foetus vaginal inoculation, and Group B was inoculated in natural estrus. At 5-7 days after treatment, estrogenic effect decreased allowing all animals to cycle regularly during the experiment. From the first week post-infection, samples of vaginal mucus were taken from all animals during 34 weeks, in order to evaluate the course of infection and the stage of the estrus cycle. Group A showed 93.6% of infected animals, and Group B showed 38%. Different doses of T. foetus were assayed to establish the vaginal infection, with a persistence of 34 weeks. Although different behavior was observed in each subgroup belonging to either Group A or Group B, there were no significant differences among the infecting doses used. The b-estradiol 3-benzoate treatment had a favorable effect on the establishment of the infection (P<0.0001), but it did not influence its persistence (P=0.1097). According to the results, an experimental mouse model is presented, appropriate for further studies on mechanisms of pathogenicity, immune response, protective evaluation of immunogen and therapeutic effect of drugs.<br>A necessidade de esclarecer a relação agente-hospedeiro na tricomoníase bovina deu motivo para o uso de modelos experimentais alternativos ao bovino. O camundongo BALB/c resultou como espécie mais adequada para a infeção vaginal com Tritrichomonas foetus, requerendo uma estrogenização prévia. Visando a necessidade de um modelo experimental sem estrogenização persistente e com ciclos estrais normais, foi avaliada a instalação e persistência da infeção vaginal no camundongo BALB/c com diferentes quantidades de T. foetus, em dois grupos experimentais. O Grupo A foi tratado com 5µg de 3-benzoato de beta estradiol, para sincronizar o estro, 48 h antes da inoculação vaginal com T. foetus, e o Grupo B foi inoculado durante o estro natural. O efeito do 3-benzoato de beta estradiol decresceu gradualmente. A totalidade dos animais ciclaram regularmente após 5-7 dias pós-tratamento. Após a primeira semana pós-infecção, todos os animais foram amostrados durante 34 semanas, para avaliar o andamento da infeção vaginal e o estádio de cío. O Grupo A apresentou 93,6% de animais infetados e o Grupo B 38%. Com diferentes dosagens de T. foetus se obteve a instalação e persistência da infecção vaginal durante 34 semanas. Embora tenham-se registrados diferentes comportamentos entre cada um dos lotes dos Grupos A e B, não houveram diferenças significativas entre as doses infectantes. O tratamento com 3-benzoato de beta estradiol teve efeito favorável na instalação da infecção (P<0,0001), porém não teve influência na persistência (P= 0,1097). Em função dos resultados obtidos, apresenta-se um modelo experimental em camundongo, adequado para aprofundar estudos sobre mecanismos de patogenicidade, resposta imune, avaliação protetora de imunógenos e o efeito terapêutico de fármacos