Hiperintensidade de sinal em T1 dos núcleos da base: relato de caso na encefalopatia portal sistêmica esquissomótica / High intensity signal in basal ganglia on T1 weighted images: case report in Manson's Schistosomiasis with portal systemic encephalopathy

Relatamos o caso de uma paciente portadora de esquistossomose mansônica com encefalopatia portal sistêmica associada a elevada intensidade de sinal em TI ao nível dos núcleos da base, devido a deposição de manganês, decorrente da presença de colaterais porto-sistêmicos. Ressaltamos os achados radiológicos por ressonância magnética e fazemos revisão bibliográfica sobre o tema. Desconhecemos relato de tal associação na bibliografia.

Efeito de vários níveis de manganês e fósforo disponível sobre a produçäo e qualidade de ovos em poedeiras / Effect of several levels of manganese and available phosphorous on egg production and egg shell quality

O efeito dos níveis de fósforo disponível na dieta (0,25 por cento, 0,35 por cento e 0,45 por cento) e a suplementaçäo de manganês (25, 50 e 75 mg/kg) para poedeiras comerciais foram avaliados por um período de oito semanas (42 a 50 semanas de idade). Todas as dietas experimentais possuíam 2678kcal EM/kg, 15,6 por cento PB e 4,12 por cento Ca. O manganês (Mn) foi suplementado com sulfato de manganês (MnSO4 5H2O). Aumentando o nível de fósforo e manganês na dieta näo se observou efeito significativo (P>0,05) no consumo de raçäo e conversäo alimentar por kg de massa de ovo. A produçäo de ovos e o peso do ovo foram (P<0,05) afetados pelo nível de manganês na dieta, obtendo-se melhor resultado com 50 e 75 mg/kg de Mn, respectivamente, mas näo com os níveis de fósforo. A espessura da casca do ovo näo foi influenciada (P>0,05) pelos níveis de Mn, mas o aumento dos níveis de fósforo disponível de 0,25 para 0,45 por cento reduziu a espessura da casca do ovo

Mechanisms underlying the genesis of post-rest contractions in cardiac muscle

Post-rest potentiation reflects basic cellular mechanisms that control cardiac muscle contraction. Transmembrane calcium influx, the Na+/Ca*+ exchange and the function of intracellular stores that liberate activator calcium upon activation are some of the mechanisms involved. Three aspects of the post-rest potentiated phenomenon were investigated, using isometrically contracting rat papillary muscles and toad ventricle strips: dependence on 1) inotropic state of steady-state contractions, 2) pause duration and Na+/Ca*+ exchange activity, and 3) the extent of transmembrane calcium influx. The results suggest that the potentiated state of post-rest contractions increases linearly with the inotropic state of preceding steady-state control contractions. As the pause duration increases from 5 to 240 s, the post-rest potentiation also increases, attaining a steady level after 30-s pauses. During the pause, the Na+/Ca*+ exchange mechanism operates at an activity level that can alter the amount of activator calcium used for post-rest contractions. Interventions that increase intracellular Na+, such as the increase of the stimulation rate from 0.5 to 1 Hz or the increase of extracxellular NaCl concentration to 160 mM, reduce the Na+/Ca*+ activity, increasing intracellular Ca*+ and post-rest potentiation. The decrease of transmembrane Ca*+ and post-rest potentiation. The decrease of transmembrane Ca*+ influx during activation increases the relative participation of the sarcoplasmic reticulum in the development of post-r5est potentiation. Reduction of extracellular Ca*+ concentration from 1.25 mM to 0.25 mM or the use of 1 uM verapamil and 2 mM manganese increases the relative potentiation of post-rest contractions. This is particulary observed in toad ventricle strips since post-rest potentiation, which does not develop under control conditions, is observed after verapamil or manganese treatment. The results suggest that the excitation contraction coupling process operating for post-rest contraction activation, unlike that operating for steady-state contraction activation, depends more on the calcium stored at intracellular sites than on transmembrane calcium influx

Studies on in vitro synthesis of serum lipoproteins in rats maintained on normal and atherogenic diets: effects of cobalt and manganese supplements at deficient and abundant doses.

The effects of Co(II) and Mn (II) supplements at abundant as well as, deficient doses on in vitro synthesis of serum lipoproteins in rats maintained on normal and atherogenic diets were studied. While an adequate oral supplement of Co(II) or iv administration of Mn (II) at very low doses to the experimental rats fed on salt-free stock ration diet produces hyperlipidemic changes in increasing C/P ratio in serum and also the serum LP content. On the other hand, the animals on atherogenic diet supplemented with deficient Co(II) or excess Mn(II) results in a lowering of hyperlipidemia and hyperlipoproteinemia, with concomitant decrease in C/P ratio. Dietary lipids (eg. cholesterol, butter-fat etc.) vis-a-vis Mn (II) deficiency or Co(II) in excess reflect a homeostatic control mechanism for keeping the excess lipid in a state of solution as lipoprotein complexes. Deficient Co(II) or excess Mn (II) in turn, results in a decrease in protein synthesis and a relatively impaired rate of secretion of protein from liver to serum. Moreover, Mn (II) deficiency increases, while its abundance, significantly restricts 14C- labelled amino acid incorporation into alpha 2-lipoprotein molecules. Neither cobalt depletion, nor its adequate oral substitution help improvise the hepatic synthesis of alpha 2-apolipoproteins in experimental animals. This situation remains unaltered even by overloading the diets with saturated fats or by other atherogenic agents, instead of vegetable oils preferably rich in mono or dienoic fatty acids.

Free amino acids in plasma and brain after chronic manganese intake in rats

We studied the levels of several free amino acids in blood plasma, striatum and frontal cortex of adult rats treated during eight months with manganese chloride added to the drinking water. No significant difference could be demonstrated in any of the amino acids analyzed