***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: A new dressing for chronic wounds  , BioFilm hydrogel dressing , was compared to a hydrocolloid dressing ( HCD ) control in a clinical trial involving 90 patients and 129 Stage I and II wounds ( defined by Enis and Sarmienti ) . The testing sites included both acute care and extended care facilities . A comparison of healing response and functional characteristics of both dressings was part of this assessment . Biofilm dressings demonstrated a healing advantage over the HCD . In addition , clinicians judged that the hydrogel dressings were easier to use and had superior fluid management capability and product integrity with minimal disruption to the healing wounds In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome , when there are some studies with a high risk , and some with a low risk of bias , they should consider including only the studies with a lower risk of bias Mixed treatment comparison ( MTC ) meta- analysis is a generalization of st and ard pairwise meta- analysis for A vs B trials , to data structures that include , for example , A vs B , B vs C , and A vs C trials . There are two roles for MTC : one is to strengthen inference concerning the relative efficacy of two treatments , by including both ' direct ' and ' indirect ' comparisons . The other is to facilitate simultaneous inference regarding all treatments , in order for example to select the best treatment . In this paper , we present a range of Bayesian hierarchical models using the Markov chain Monte Carlo software WinBUGS . These are multivariate r and om effects models that allow for variation in true treatment effects across trials . We consider models where the between-trials variance is homogeneous across treatment comparisons as well as heterogeneous variance models . We also compare models with fixed ( unconstrained ) baseline study effects with models with r and om baselines drawn from a common distribution . These models are applied to an illustrative data set and posterior parameter distributions are compared . We discuss model critique and model selection , illustrating the role of Bayesian deviance analysis , and node-based model criticism . The assumptions underlying the MTC models and their parameterization are also discussed Pressure ulcers are common among elderly nursing home residents . To be effective in managing these wounds , a dressing should maintain a moist environment , facilitate healing , absorb exu date , remain in place for a number of days , and prevent trauma to the surrounding skin . An 8-week , open , r and omized , multicenter , controlled study was conducted to compare the effects of a new self-adherent soft silicone dressing and a self-adherent hydropolymer dressing on Stage II pressure ulcers . Thirty-eight ( 38 ) residents participated in the study . Eighteen residents ( mean age 83.8 years , range 74.9 to 95.1 years ) were r and omized to wound management with a soft silicone dressing , and the ulcers of 20 residents ( mean age 82.5 years , range 66.4 to 91.9 years ) were managed with a hydropolymer dressing .  Wound healing , wound and surrounding skin characteristics , and ease of dressing removal were measured and documented . During the study , eight ( 44 % ) ulcers in the soft silicone group and 10 ( 50 % ) in the hydropolymer dressing group healed . Both dressings were changed approximately once a week and no differences in signs of inflammation , amount of exu date and odor , or incidence of leakage were observed . Damage to the surrounding skin , maceration , and dressing removal difficulties were less common with the soft silicone dressing . Differences in tissue damage between the two dressings were significant during weeks 1 , 2 , and 3 ( P < 0.05 ) . Studies with a larger sample size are needed to confirm these findings An occlusive hydrocolloid dressing ( Comfeel Ulcus ) was compared with a conventional wet saline gauze dressing regarding the effect on ulcer cleansing and healing processes , experience of pain and the consumption of nursing time , in a controlled , r and omized and partially single-blind study with parallel groups of long-stay patients with pressure sores . After a few weeks ' treatment the relative decrease in ulcer areas with time was larger in the group treated with the hydrocolloid dressing . The difference was almost statistically significant at week 5 ( p = 0.054 ) and definite at week 6 ( p = 0.006 ) . At week 6 the median remaining ulcer area in per cent of the initial area was 0 % in the hydrocolloid dressing group and 31 % in the group treated with saline gauze ( p = 0.016 ) . Analysis of the healing distribution function showed the hydrocolloid dressing to be more effective , although the overall difference was non-significant ( p = 0.15 ) . Care of the pressure sore took significantly less time with hydrocolloid dressings A hydropolymer dressing ( Tielle ) and a hydrocolloid dressing ( Granuflex ) were compared in a r and omised controlled clinical study involving 100 patients with leg ulcers and 99 patients with pressure sores in the community . Statistically significant differences in favour of the hydropolymer dressing were detected for dressing leakage and odour production , but no statistically significant differences were recorded in the number of patients with either leg ulcers or pressure sores who healed in each treatment group OBJECTIVE To compare the clinical efficacy of a collagen dressing covered with a foam dressing with the same foam used as a primary dressing in stagnating granulating pressure ulcer patients . METHOD Patients were r and omised to receive either a foam dressing ( Suprasorb P ; Lohmann & Rauscher ) as a primary dressing ( group A ) , or a combination of a collagen dressing ( Suprasorb C ; Lohmann & Rauscher ) covered with the same foam dressing ( group B).Wound fluid was collected and evaluated prior to treatment ( day 0 ) , and on days 3,7 , 14 and 21 .The level and expression of matrix metalloproteinases ( MMPs ) MMP-2 and MMP-9 , and tissue inhibitors of metalloproteinases ( TIMPs ) TIMP- I and TIMP-2,as well as elastase content in wound fluid and angiogenesis , were evaluated , comparing results on day 0 and day 2 I.Time to ulcer healing , reduction in ulcer area , safety of treatment , patient-reported ulcer pain and comfort of the dressing regimen were evaluated as secondary outcomes . Patients received st and ard preventive measures , in line with the pressure ulcer prevention guidelines . RESULTS Ten patients were included in the pilot ; five were treated with the foam dressing ( group A ) and five patients received the collagen dressing , using the foam as a secondary dressing ( group B).Wound fluid from group B displayed a significant positive effect on angiogenesis ( p < 0.05 ) compared with group A. In the collagen and foam groupTIMP- I and -2 increased faster and levels were higher than in group A. Furthermore , MMP-2 , MMP-9 ( p < 0.04 ) and elastase in group B showed faster and greater decrease in levels , compared with group A , indicating a faster and superior reduction of inflammation . In both groups the ulcers started to heal , with a faster onset of healing for group B. CONCLUSION The results of this pilot support published data on the use of collagen dressings compared with foam for stagnating wounds , shown in clinical studies . DECLARATION OF INTEREST This study was supported with an educational grant by Lohmann & Rauscher GmbH.Apart from DrAbel , the sponsors had no role in the design or conduct of the study , in the collection , analysis and interpretation of the data , or in the preparation , review or approval of the manuscript . DrAbel gave input to the study design from a scientific perspective . None of the authors received administrative , technical or material support for the conduct of this study .The authors have no other relevant financial interests to declare Platelet-rich growth factor ( PRGF ) is a natural source of growth factors ( GF ) , while hyaluronic acid ( HA ) is a biopolymer present in the extracellular matrix of skin , cartilage , bone , and brain , among other tissues . Both are involved in the pathophysiological mechanisms underlying wound healing . The objective of this study was to evaluate the clinical efficacy ( as measured by ulcer area ) and safety ( as measured by signs of infection ) of PRGF and PRGF plus HA in the treatment of pressure ulcers ( PUs ) . Patients ( N = 100 ) with 124 Stage II – III PUs were r and omized to a control group ( n = 25 PUs ) for st and ard care or to case groups for treatment with one ( n = 34 PUs ) or two ( n = 25 PUs ) doses of PRGF from their own peripheral blood , or two doses of PRGF plus HA ( n = 40 PUs ) . All ulcers were followed up every 3 days for a 36-day period . At 36 days , a significant reduction in ulcer area ( p ≤ .001 ) was observed in all treatment groups , with a mean reduction of more than 48.0 % versus baseline . The greatest mean reduction ( 80.4 % vs. baseline ) was obtained with the PRGF plus HA regimen . Complete wound healing was observed in 32.0 % of PUs treated with two doses of PRGF ( p ≤ .002 ) and in 37.5 % of those treated with two doses of PRGF plus HA ( p ≤ .004 ) . There were no signs of infection in any PUs during the 36-day follow-up period . The degree of wound healing was inversely correlated with the consumption of drugs such as statins and with the peripheral blood platelet levels of patients at baseline BACKGROUND Chronic ulcers owing to pressure cause complications with respect to immobilization and develop through limited blood circulation . There are different treatments for these ulcers ; nonetheless , the search for an efficient and economical option continues . One choice could be collagen-polyvinylpyrrolidone ( clg-pvp ) . Presence of pressure ulcers in hospitalized patients constitutes a frequent medical problem which is difficult to manage and can be an entry route for infection . Also , restoring the dermic continuity offers a means of improving a patient 's quality -of-life . OBJECTIVE The aim of the study was to analyze whether cicatrization on pressure ulcers presents more rapidly with local cleaning with soap , application of zinc oxide paste and clg-pvp compared with local cleaning with soap , application of zinc oxide paste and placebo ( saline solution with polyvinylpyrrolidone ) . METHODOLOGY From July 2002 to April 2003 the authors conducted a clinical , comparative , prospect i ve , longitudinal , r and omized study . Coded flasks containing either clg-pvp or placebo were design ated for patients according to a table of r and om numbers . The clg-pvp or placebo was applied to each patient 's ulcers at a rate of 1.5 ml intradermically at the four equi-spaced points around the ulcer . The nominal diameter of each ulcer was measured at the start of the study and then weekly over a 3-week period . Statistical analysis was carried out using the SPSS ( version 10 ; SPSS Inc. , Chicago , IL ) software program . RESULTS The group treated with clg-pvp experienced a reduction in mean ulcer size from 3.4 to 1.41 cm in diameter , whereas in the placebo group the reduction was from 2.9 to 1.58 cm in diameter . Despite the greater diameter reduction in the first group , the lack of a statistically significant difference could have result ed from the short follow-up period and small sample size OBJECTIVE : To compare clinical performance of a transparent absorbent acrylic dressing ( 3 M Tegaderm Absorbent Clear Acrylic Dressing ] TAAD [ ; 3 M Company , St Paul , MN ) and a hydrocolloid dressing ( HD ] DuoDERM CGF , ConvaTec , ER Squibb & Sons , Princeton , NJ [ ) in the management of Stage II and shallow Stage III pressure ulcers . DESIGN : Prospect i ve , open-label , r and omized , comparative , multisite clinical evaluation . Patients were followed up for a maximum of 56 days or until their ulcer healed . At weekly intervals , investigators conducted wound assessment s and dressing performance evaluations . SETTING : Wound care clinics , home care , and long-term care . PATIENTS : Thirty-five patients received the TAAD , and 37 received the HD .  OUTCOME MEASURES : Dressing performance assessment s , patient comfort , dressing wear time , and wound healing were measured . RESULTS : The majority of investigator assessment s favored the TAAD . Considerations given included the ability to center dressings over the ulcer ( P = .005 ) , ability to assess the ulcer before ( P < .001 ) and after ( P < .001 ) absorption , barrier properties ( P = .039 ) , patient comfort during removal ( P < .001 ) , overall patient comfort ( P = .048 ) , conformability before ( P = .026 ) and after ( P = .001 ) absorption , ease of removal ( P < .001 ) , nonadherence to wound bed ( P < .001 
    Output:
    
Consequently we are unable to determine which dressings or topical agents are the most likely to heal pressure ulcers , and it is generally unclear whether the treatments examined are more effective than saline gauze .