Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

Most Amazonian soils are highly weathered and poor in nutrients. Therefore, photosynthesis and plant growth should positively respond to the addition of mineral nutrients. Surprisingly, no study has been carried out in situ in the central Amazon to address this issue for juvenile trees. The objective of this study was to determine how photosynthetic rates and growth of tree saplings respond to the addition of mineral nutrients, to the variation in leaf area index of the forest canopy, and to changes in soil water content associated with rainfall seasonality. We assessed the effect of adding a slow-release fertilizer. We determined plant growth from 2010 to 2012 and gas exchange in the wet and dry season of 2012. Rainfall seasonality led to variations in soil water content, but it did not affect sapling growth or leaf gas exchange parameters. Although soil amendment increased phosphorus content by 60 %, neither plant growth nor the photosynthetic parameters were influenced by the addition of mineral nutrients. However, photosynthetic rates and growth of saplings decreased as the forest canopy became denser. Even when Amazonian soils are poor in nutrients, photosynthesis and sapling growth are more responsive to slight variations in light availability in the forest understory than to the availability of nutrients. Therefore, the response of saplings to future increases in atmospheric [CO2] will not be limited by the availability of mineral nutrients in the soil

Cytokine expression in mast cells and rat lung tissue

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN004246 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Eotaxin and eotaxin receptor (CCR3) expression in Sephadex particle-induced rat lung inflammation

The β chemokine eotaxin is a potent eosinophil activator and chemoattractant. We examined immunohistochemically eotaxin protein expression in a range of normal rat tissues and in rat lung during Sephadex particle-induced pulmonary inflammation. The time course of eotaxin expression in lung at various time points after Sephadex administration was related to the appearance of eosinophils in the bronchoalveolar lavage fluid and tissue distribution of eotaxin receptor (CCR3) positive cells. Results showed that eotaxin protein was constitutively expressed by both lung airway epithelial cells and gut epithelial cells in normal tissues in the absence of inflammation. During Sephadex induced pulmonary inflammation, eotaxin expression increased in alveolar macrophages prior to the major increase in eosinophil numbers which reached a peak at 72 h. The pattern of eotaxin pulmonary expression and the location of CCR3 receptor positive cells suggest a chemoattractant gradient resulting in migration firstly into the tissue and subsequently through the airway epithelium into the airways. Treatment of rats with the glucocorticoid dexamethasone or the immunosuppressant cyclosporin A reduced eosinophil entry into lung tissue and airways but had no apparent effect on eotaxin expression in vivo, indicating that both these drugs inhibit eosinophil recruitment either by an eotaxin-independent mechanism, or by targetting factors that synergise with eotaxin, or an event post eotaxin expression

Estimulação elétrica neuromuscular de média freqüência (russa) em cães com atrofia muscular induzida Medium frequency neuromuscular electrical stimulation (russian) in dogs with induced muscle atrophy

A estimulação elétrica neuromuscular (EENM) de média freqüência (Russa) ou de Kotz pode ser empregada para a recuperação de massa muscular em animais apresentando atrofia muscular por desuso. Assim, o objetivo deste trabalho foi empregar a EENM de média freqüência no quadríceps femoral de cães com atrofia muscular induzida, avaliando-se a ocorrência de ganho de massa. Foram utilizados oito cães em dois grupos denominados de GI ou controle e de GII ou tratado. Para a indução da atrofia muscular, a articulação fêmoro-tíbio-patelar esquerda foi imobilizada por 30 dias. Após 48 horas da remoção, foi realizada a EENM nos cães do grupo II, três vezes por semana, com intervalo de 48 horas cada sessão, pelo período de 60 dias. Foram avaliadas a mensuração da perimetria da coxa, da goniometria do joelho, as enzimas creatina-quinase (CK) e morfometria das fibras musculares em cortes transversais do músculo vasto lateral, colhido mediante a biópsia muscular. A EENM foi empregada no músculo quadríceps femoral numa freqüência de 2.500Hz, largura de pulso de 50% e relação de tempo on/off de 1:2. Não houve diferença significativa quanto aos valores de perimetria da coxa e a atividade da enzima CK entre os grupos I e II. Na goniometria, houve diminuição significativa (P<0,05) da amplitude articular após a remoção do aparelho de fixação externa somente nos animais do grupo II, em comparação a com tempo zero. Quanto à morfometria das fibras do músculo vasto lateral, foram notados valores maiores de área das fibras no grupo Tratado, em relação ao Controle (P<0,05), no dia 90, e, no grupo Tratado, entre os dias zero e 90. A EENM de média freqüência ocasiona hipertrofia do músculo vasto lateral em cães após a atrofia muscular induzida.<br>The medium frequency neuromuscular electrical stimulation (NMES) (Russa) or Kotz is designed for recuperation of muscle mass in dogs with muscular atrophy in disuse. This study aims to utilize medium frequency NMES on the femoral quadriceps of dogs with induced muscular atrophy and evaluate the occurrence of gain in mass. Eight dogs in two groups denominated GI, or control, and GII, or treated were used. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days. NMES treatment began 48 hours after the removal of the immobilization device on dogs from group II and was carried out three times per week, with an interval of 48 hours between each session, during 60 days. The following parameters were measured: thigh perimeter, goniometry of the knee, creatine kinase (CK) enzymes and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle, collected through a muscular biopsy. EENM was utilized on the femoral quadriceps at a frequency of 2500 Hz, with pulse duration of 50%, and the time on/off was at a proportion of 1:2. There was no significant difference between the thigh perimeter and the activity of enzyme CK between groups I and II. As for the goniometry a significant increase (P<0,05) was observed among 0 and 30 days after the immobilization in group II. As for the morphometry of the fibers of the vastus lateralis, a significant increase (P<0,05) was observed in the transversal area of the treated group on the 90th day when compared with that observed at the time of immobilization and among the groups, group II presented a greater transversal area (P<0.05) on the 90th day. The medium frequency NMES brings about a hypertrophy of the vastus lateralis muscle in dogs after induced muscular atrophy