A pilot randomised controlled trial of negative pressure wound therapy to treat grade III/IV pressure ulcers [ISRCTN69032034

ABSTRACT: BACKGROUND: Negative pressure wound therapy (NPWT) is widely promoted as a treatment for full thickness wounds, however there is a lack of high-quality research evidence regarding its clinical and cost effectiveness. A trial of NPWT for the treatment grade III/IV pressure ulcers would be worthwhile but premature without assessing whether such a trial is feasible. The aim of this pilot randomised controlled trial was to assess the feasibility of conducting a future full trial of NPWT for the treatment of grade III and IV pressure ulcers and to pilot all aspects of the trial. METHODS: This was a two centre (acute and community), pilot randomised controlled trial. Eligible participants were randomised to receive either NPWT or Standard Care (SC) (spun hydrocolloid, alginate or foam dressings). The primary outcome measure was time to healing of the reference pressure ulcer. Secondary outcome measures included recruitment rates, frequency of treatment visits, resources used and duration of follow-up. RESULTS: 312 patients were screened for eligibility into this trial over a 12-month recruitment period and 12/312 participants (3.8%) were randomised; six to NPWT and six to SC. Only one reference pressure ulcer healed (NPWT group) during follow up (time to healing 79 days). The mean number of treatment visits per week was 3.1 (NPWT) and 5.7 (SC). 6/6 TNP and 1/6 SC participants withdrew from their allocated trial treatment. The mean duration of follow-up was 3.8 (NPWT) and 5.0 (SC) months. CONCLUSIONS: This pilot trial yielded vital information for the planning of any future full study including a projected recruitment rate, required duration of follow up and extent of research nurse support required. Data were also used to inform cost-effectiveness and value of information analyses which were conducted alongside the pilot trial.     

Effects of simulated browsing on growth and leaf chemical properties in Colophospermum mopane saplings

Browsing intensity influences a plant's response to herbivory. Plants face a trade-off between investment in the production of secondary compounds and investment in growth. To elucidate this trade-off, we simulated four browsing intensities (0%, 50%, 75% and 100%) on mopane saplings, Colophospermum mopane (J.Kirk ex Benth.) J.Léonard, in a greenhouse experiment. This showed that, with increasing defoliation intensity, plants change their investment strategy. At intermediate levels of defoliation (50%), mopane saplings increased the synthesis of condensed tannins, so that tannin concentrations followed a hump-shaped relation with defoliation intensity, with significantly higher tannin concentration at intermediate defoliation levels. When defoliated heavily (75% and 100%), tannin concentrations dropped, and plants were carbon stressed as indicated by a reduced growth rate of the stem diameter, and leaf production and mean individual leaf mass were reduced. This suggests that, at intermediate defoliation intensity, the strategy of the plants is towards induced chemical defences. With increasing defoliation, the relative costs of the secondary metabolite synthesis become too high, and therefore, the plants change their growing strategy. Hence, browsers should be able to benefit from earlier browsing by either adopting a low or a relatively high browsing pressure.     

Optimization of a working cryopreservation protocol for Pinus patula embryogenic tissue

Summary The protocol currently used to cryopreserve Pinus patula embryogenic tissue was investigated in an attempt to improve and optimize the recovery of tissue. This investigation describes two aspects that influence tissue recovery after cryopreservation: (i) the effects of precooling tissue prior to immersion into liquid nitrogen; and (ii) whether the choice of supports onto which the recovered tissue is suspended improved the recovery rate. Results indicated that precooling tissue to −70°C prior to immersion into liquid nitrogen was superior to precooling to −30°C or direct immersion in liquid nitrogen (−196°C). Tissue recovery improved when polyester grids were used as supports, and was slowest on filter paper supports.     

How to Use Secondary Data on Seafood Contamination for Probabilistic Exposure Assessment Purposes? Main Problems and Potential Solutions

Seafood consumption is related to both favorable health benefits of nutrients and to potential adverse health impacts of chemical contamination. To quantify the magnitude of this dilemma, probabilistic intake assessments can be performed. One step in such a procedure involves the determination of nutrient and contaminant concentrations in seafood for which data need to be collected. This article describes the process of building up a database containing previously published contaminant concentrations in seafood, and defining input distributions characterizing the variability. During the constitution of the database, several problems influencing the comparability of the data were encountered related to (1) sampling plans of the published data; (2) sample handling prior to analysis; (3) analytical methodologies; (4) the format of reporting results; and (5) missing data. Different solutions for these methodological problems have been developed. Contaminant concentrations ranges per gram fresh weight of 2.4–4390.0 ng for mercury, 0.1–5736.6 ng for the sum of indicator PCB, 0.002–115.000 pg TEQ for the sum of all PCBs, 0.002–34.400 pg TEQ for dioxins, and 0.006–126.000 pg TEQ for total of dioxin-like compounds were found. This work confirms that more guidelines are needed to standardize the analytical methodologies to be used and the format for result reporting in order to improve the comparability of data critical to conduct a human intake and risk-benefit assessment.