Experimental model to study intervertebral disc herniation

OBJETIVO: Apresentar um modelo experimental de hérnia de disco e sua validação para estudo da hiperalgesia mecânica e térmica produzidas pelo contato do núcleo pulposo (NP) com as estruturas nervosas envolvidas nessa afecção. MÉTODOS: Foram utilizados ratos Wistar, sendo o NP autólogo retirado da região sacrococcígea e depositado sobre a dura-máter, raiz nervosa ou gânglios das raízes dorsais L4, L5 ou L6. Os experimentos foram divididos em quatro etapas: 1ª) determinação da estrutura nervosa mais sensível ao contato com o NP; 2ª) identificação do melhor nível lombar para a indução da hiperalgesia; 3ª) determinação da ausência de lesão motora; e 4ª) determinação da influência do procedimento cirúrgico no desenvolvimento do processo inflamatório. A hiperalgesia foi avaliada nos testes de von Frey eletrônico e de Hargreaves e a função motora, pelo teste de rota-rod. RESULTADOS: O NP induziu hiperalgesia de maior intensidade na pata quando em contato com o gânglio da raiz dorsal (GRD) do que em contato com a dura-máter ou a raiz nervosa. Quando em contato com o GRD-L5, o NP induziu hiperalgesia ainda maior que a induzida pelo contato com os GRDs L4 e L6. Não foram observadas lesão motora e influência do processo inflamatório cirúrgico sobre a hiperalgesia. CONCLUSÃO: O GRD é a estrutura mais sensível aos componentes do NP para a produção da hiperalgesia, sendo o quinto nível lombar o que apresentou maior alteração nas sensibilidades mecânica e térmica avaliadas na pata dos animais, de acordo com os métodos utilizados.OBJECTIVE:The purpose of this study is to present an experimental model of disc herniation and to validate such model to study mechanic and thermal hyperalgesia produced by the contact of the nucleus pulposus (NP) with nerve structures involved in this condition. METHODS: The authors used Wistar rats, the autologous NP being removed from the sacrococcygeal region and deposited on the dura mater, nerve root, or L4, L5, or L6 dorsal root ganglia. The experiments were divided into four steps: 1) determining the nerve structure that is the most sensitive to the contact with NP; 2) identifying the best lumbar level to induce hyperalgesia; 3) determining absence of a motor lesion; and 4) determining the impact of the surgical procedure upon the inflammatory process. Hyperalgesia was evaluated by the von Frey electronic test and the Hargreaves test, and the motor function was evaluated by the rota-rod test. RESULTS: NP induced higher intensity hyperalgesia in the paw when it was in contact with the dorsal root ganglion (GRD) than when it was in contact with the dura mater or the nerve root. Contact with GRD-L5, led NP to induce even higher hyperalgesia than that induced in the contact with L4 and L6 GRDs. No motor lesion and impact of the surgical inflammatory process on hyperalgesia were observed. CONCLUSION: GRD is the structure that is most sensitive to NP components to produce hyperalgesia, the fifth lumbar level being that showed the greatest change in the mechanic and thermal sensitivities evaluated in the paws of the animals, under the methods used

Interconnectedness during high water maintains similarity in fish assemblages of island floodplain lakes in the Amazonian Basin

We conducted a study to test the hypothesis that interconnectedness among island floodplain lakes and the adjacent Solimões River during the flood stage of the hydrologic cycle is enough to maintain similarity in fish species assemblages. Gill net samples were collected during high and low water periods for three consecutive years (July 2004 to July 2006) in four lakes on Paciência Island. Two lakes, Piranha and Ressaca, are connected to the river all year, and the other two, Preto and Cacau, which are in the center of the island, are isolated during low water periods. The abundance, species richness and evenness of the fish assemblages in these lakes did not differ according to their relative positions or the season of the hydrological cycle, which confirmed our hypothesis. However, fish abundance during the dry season was greater than in the flood season. Apparently, the short period of full connection between the lakes is enough to allow the colonization of all fish species, but not to cause similar abundances. Our study indicates that persistence of the species composition of island floodplain lakes is primarily due to the annual replenishment of fish to the lakes during the flood season

Biofertilizante agrobio: Uma alternativa no controle da mancha bacteriana em mudas de pimentão (Capsicum annuum l.)

Agrobio é um biofertilizante líquido fabricado à base de esterco bovino, água, melaço e sais minerais, que são submetidos a um processo de fermentação à temperatura ambiente por 56 dias em recipientes abertos. Este produto tem sido largamente utilizado com sucesso por agricultores orgânicos e convencionais em todo o estado do Rio de Janeiro, no controle de várias enfermidades vegetais em diferentes culturas. Em bioensaios realizados em casa de vegetação, observou-se uma ação bacteriostática equivalente a de produtos químicos comerciais contra Xanthomonas campestris pv. vesicatoria em mudas de pimentão (Capsicum annuum L.), numa concentração de 5%. Nos bioensaios in vitro, onde foram testadas as concentrações de 2, 5 10 e 50% do Agrobio comercial, observouse que, a partir da concentração de 5%, ocorreu um nível satisfatório de inibição do crescimento bacteriano, apesar deste ter sido inferior ao obtido com o uso de sulfato de cobre e sulfato de estreptomicina

Measuring nutritional knowledge using Item Response Theory and its validity in European adolescents

Objective: To analyse the Nutritional Knowledge Test (NKT) using Item Response Theory (ITR) analysis and to assess the construct validity of the Nutritional Knowledge Scale (NKTS) and its associations with adolescent food group consumption and nutritional biomarkers. DesignCross-sectional study: SettingMulticentre investigation conducted in ten European cities.ParticipantsAdolescents aged 12·5-17·5 years (n 3215) who completed over 75 % of the NKT. Results: Factor analysis indicated that the NKT can be analysed with a one-dimensional model. Eleven out of twenty-three items from the NKT presented adequate parameters and were selected to be included in the NKTS. Nutrition knowledge was positively associated with consumption of fruits, cereals, dairy products, pulses, meat and eggs, and fish, as well as with blood concentrations of vitamin C, ß-carotene, n-3 fatty acids, holo-transcobalamin, cobalamin and folate; nutrition knowledge was negatively associated with intake of olives and avocado, alcohol and savoury snacks. Conclusions: The NKTS assessed nutritional knowledge adequately and it is proposed as a new tool to investigate this subject in future studies

Estudos sobre a nutrição mineral do milho: II - deficiências de macronutrientes na variedade Piranão

Corn plants, Piranão variety, were grown in nutrient solution, complete and with omission of one macronutrient each time, in order to gain information on the effects of treatments on growth, symptoms of deficiency, and mineral composition of the leaves. The following symptoms of deficiency were obtained: Nitrogen -- plants underdeveloped; "V" shaped chlorosis beginning in the older leaves followed by drying and necrosis; Phosphorus - older leaves dark green with a purple hve; Potassium - plants underdeveloped; marginal chlorisis and necrosis in the older leaves; iron induced chlorosis in the younger leaves; Calcium - plants very underdeveloped due to death of apical merystem; younger leaves showing tip and marginal chlorosis and afterwards necrosis and break down of the tissue; wide whitish areas in the younger leaves; Magnesium - plants very underdeveloped; internerval chlorosis in older leaves first, proceeding to the young ones; Sulfur - absence of marked symptoms, except for a slight chlorosis in the younger leaves. Dry matter production obeyed the following decreasing order: Complete, minus S, minus P, minus K, minus Mg, minus N and minus Ca. Ears were obtained only in treatments complete and minus S. Top/root ratio decreased according to this order: minus S, complete, minus K, minus Mg, minus N, minus P and minus Ca. The macronutrient content for the treatment complete was the following respectively for lower and upper, leaves: N - 2.76 and 2.52%; P - 0.59 and 0.53%; K - 2.25 and 2.26%;Ca - 2.17 and 1.85;Mg - 0.82 and0.66;S - 0.38 and 0.32. The values of the element corresponding to each treatment were: N - 1.84 and 1.22 (that is: lower leaves in the minus N plants had 1 84% N, whereas the upper leaves in same treatment had 1.22% N; P - 0.14 and 0.17%; K - 0.29 and 0.78%; Ca - 0.29 and 0.05; Mg -0.09 and 0.05%; S- 0.31 and 0.26%.Foram induzidos sintomas de carência de macronutrientes no milho, var. Piranão, exceto no caso do enxofre. Os níveis foliares de N, P, K, Ca, Mg e S foram determinados nas plantas sujeitos à nutrição completa e às deficiências de macronutrientes

Biodigestor: uma ferramenta para o ensino de química

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