Propagação de pteridófitas in vitro e in vivo através de esporos Fern propagation in vitro and in vivo from spores

Sujeitas ao processo de extinção, em decorrência do extrativismo, as samambaias arbóreas Dicksonia sellowana (Presl.) Hook e Cyathea schanschin Mart, das quais se obtémo xaxim, são espécies ainda pouco estudadas quanto à propagação. Com o objetivo de desenvolver um método adequado à propagação destas espécies, através de esporos, realizaram-se experimentos in vitro e in vivo. Para a desinfecção dos esporos, utilizaram-se soluções de hipoclorito de cálcio, em diferentes concentrações, ou de sódio, comparando-se sua eficiência. Para o cultivo in vitro, empregaram-se os meios nutritivos de Murashige e Skoog modificado e de Jones e a solução de Knop modificada. Na cultura in vivo utilizaram-se xaxim, estagno, terriço ou tijolo fragmentado. Como condições de cultivo, manteve-se a temperatura a 25 &plusmn;1&deg;C e o fotoperíodo de 16 horas. Apesar da elevada contaminação durante o processo de germinação in vitro e in vivo, a desinfecção com hipoclorito de cálcio a 2% foi mais eficiente. Os esporos germinaram em 4 a 8 semanas e os prótalos formaram-se após 30 a 40 dias. Obteve-se maior percentagem de germinação e formação de prótalos com os meios de Jones e Knop, bem como xaxim e esfagno, e a germinação de esporos ocorreu mais rapidamente na ausência de esporângios.<br>The objective of this experiment was to study the fern propagation from spores of Cyathea schanschin Mart and Dicksonia sellowiana (Presl.) Hook. The spores were decontaminated in calcium or sodium hypochlorite solutions. The in vitro experiments were performed with the media: MS modified, Jones or Knop's solution modified. Tree-fern fibre, sphagnum moss, loam soil or brick peaces were, used for the in vivo experiments. The temperature was mantained at 25 &plusmn; 1&deg;C and 16 hours of photoperiod for both treatments (In vivo and in vitro cultures). Besides the high percentage of contamination during the germination process, in vitro and in vivo, the best results were obtained with decontamination made in a 2% sodium hypochlorite solution. The spores germination occurred after a period of 4 to 8 weeks and the prothalli were formed 30 to 40 days latter. There was a high percentage of germination and prothalli formation in Jones and Knop media, and tree-fern fibre and sphagnum moss substrates

Is there evidence to support the use of lateral positioning in intensive care? A systematic review

A systematic review of randomised clinical trials was conducted to investigate the efficacy and safety of use of the lateral position in the management of ventilated intensive care patients. One review article and I I empiric studies, which were mostly of low methodological quality, met the eligibility criteria. Large individual variations in PaO2 response to lateral positioning were demonstrated. Greatest improvement in PaO2 occur-red in patients with unilateral pulmonary infiltrates positioned with the bad lung tip versus bad lung down (average difference =33.6 mmHg (range 0-58), effect size 1.13 (95% Cl: 0.44, 1.19, P=0.001)) or supine (average difference=27 mmHg (range 5-42), effect size 0.58 (95% Cl: 0.11, 1.06, P=0.017)). This effect appeared to be most prominent in patients with widespread, unilateral infiltrates. Lung compliance was not affected by lateral positioning. Haemodynamic compromise was evident with lateral positioning of greater than 60 degrees to the right side in patients requiting vasopressors and/or with right ventricular dysfunction; or with lateral positioning in postoperative coronary artery bypass graft patients. No studies were found that had investigated the effect of routine applications of the lateral positioning to improve, prevent or treat pneumonia, decrease mortality or influence other long-term outcomes. The results of this review demonstrate the limited evidence available to support the use of lateral positioning in the intensive care environment. More data reporting the long-term effects of lateral position on long-term outcomes would aid clinical decision making and may improve the application of patient positioning in critical care environments

COMPARATIVE PROPERTIES OF 400-GeV/c PROTON - PROTON INTERACTIONS WITH AND WITHOUT CHARM PRODUCTION

A comparative analysis of the global properties of 400 GeV/c proton-proton interactions with and without charm production is presented. Multiplicities, momentum distributions, sphericity and thrust of these interactions are compared