Dialkylcarbamoyl chloride (DACC)-coated dressings in the management and prevention of wound infection: A systematic review

Objective: Dialkylcarbomoyl chloride (DACC)-coated dressings (Leukomed Sorbact and Cutimed Sorbact) irreversibly bind bacteria at the wound surface that are then removed when the dressing is changed. They are a recent addition to the wound care professional's armamentarium and have been used in a variety of acute and chronic wounds. This systematic review aims to assess the evidence supporting the use of DACC-coated dressings in the clinical environment. Method: We included all reports of the clinical use of DACC-coated dressings in relation to wound infection. Medline, Embase, CENTRAL and CINAHL databases were searched to September 2016 for studies evaluating the role of DACC-coated dressings in preventing or managing wound infections. Results: We identified 17 studies with a total of 3408 patients which were included in this review. The DACC-coating was suggested to reduce postoperative surgical site infection rates and result in chronic wounds that subjectively looked cleaner and had less bacterial load on microbiological assessments. Conclusion: Existing evidence for DACC-coated dressings in managing chronic wounds or as a surgical site infection (SSI) prophylaxis is limited but encouraging with evidence in support of DACC-coated dressings preventing and treating infection without adverse effects

Inhibition of DDAH1, but not DDAH2, results in apoptosis of a human trophoblast cell line in response to TRAIL.

STUDY QUESTION: Does inhibition of dimethylarginine dimethylaminohydrolase (DDAH) increase the sensitivity of trophoblasts to TRAIL-induced apoptosis? SUMMARY ANSWER: Inhibition of DDAH1, but not DDAH2, increases the sensitivity of trophoblasts to TRAIL-induced apoptosis. WHAT IS KNOWN ALREADY: Successful human pregnancy is dependent on adequate trophoblast invasion and remodelling of the maternal spiral arteries. Increased trophoblast apoptosis is seen in pregnancies complicated by pre-eclampsia. The mechanism underlying this increase is unknown. We have previously shown that nitric oxide (NO) is involved in regulating trophoblast motility and invasion, and have also demonstrated an important role for NO in regulating trophoblast sensitivity to apoptotic stimuli. DDAH is an enzyme that metabolizes asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis, previously shown to be elevated in the plasma of pre-eclamptic mothers. STUDY DESIGN, SIZE, DURATION: This study used the human extravillous trophoblast-derived cell line SGHPL-4 cells. All experiments were performed at least three times. PARTICIPANTS/MATERIALS, SETTING, METHODS: The effect of DDAH on trophoblast apoptosis was examined using siRNA and time-lapse microscopy. Changes in the expression of DDAH were followed by PCR and western blot analysis. Receptor expression was followed by flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE: Inhibiting the expression of DDAH1, but not DDAH2, resulted in a significant increase in the sensitivity of the EVT cell line SGHPL-4 to tumour necrosis factor related apoptosis inducing ligand (TRAIL) induced apoptosis (P < 0.01). This response could be mimicked by the addition of Asymmetric Dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis and the substrate for both isoforms of DDAH. We further showed that this increased sensitivity to apoptosis is accompanied by a significant increase in the expression of TRAIL receptor 2 (TR2; P < 0.05) but not TRAIL receptor 1 (TR1). LIMITATIONS, REASONS FOR CAUTION: This study was performed only in vitro using a well characterized trophoblast cell line, SGHPL-4, derived from first trimester extravillous trophoblasts. WIDER IMPLICATIONS OF THE FINDINGS: This study provides new insight into the role of the DDAH/ADMA pathway in the regulation of trophoblast function. Both dysregulation of DDAH and the accumulation of ADMA have been associated with the development of pre-eclampsia. This is the first study to implicate the DDAH/ADMA pathway as a mechanism that might underlie the poor trophoblast invasion seen in this common pregnancy disorder. STUDY FUNDING/COMPETING INTERESTS: B.A.L. was supported by a grant from Action Medical Research UK (SP4577). A.E.W. was supported by a grant from the Wellcome Trust (091550). There are no competing interests and the authors have no conflict interest to declare

Dynamics of digging in wet soil

Numerous animals live in, and locomote through, subsea soils. To move in a medium dominated by frictional interactions, many of these animals have adopted unique burrowing strategies. This paper presents a burrowing model inspired by the Atlantic razor clam ({\it Ensis directus}), which uses deformations of its body to cyclically loosen and re-pack the surrounding soil in order to locally manipulate burrowing drag. The model reveals how an anisotropic body -- composed of a cylinder and sphere varying sinusoidally in size and relative displacement -- achieves unidirectional motion through a medium with variable frictional properties. This net displacement is attained even though the body kinematics are reciprocal and inertia of both the model organism and the surrounding medium are negligible. Our results indicate that body aspect ratio has a strong effect on burrowing velocity and efficiency, with a well-defined maximum for given kinematics and soil material properties

An idealized numerical study of tropical cyclogenesis and evolution at the Equator

Tropical cyclone formation and evolution at, or near, the Equator is explored using idealized three‐dimensional model simulations, starting from a prescribed, initial, weak counterclockwise rotating vortex in an otherwise quiescent, nonrotating environment. Three simulations are carried out in which the maximum tangential wind speed (5 m surn:x-wiley:qj:media:qj3701:qj3701-math-0001) is specified at an initial radius of 50, 100, or 150 km. After a period of gestation lasting between 30 and 60 hr, the vortices intensify rapidly, the evolution being similar to that for vortices away from the Equator. In particular, the larger the initial vortex size, the longer the gestation period, the larger the maximum intensity attained, and the longer the vortex lifetime. Beyond a few days, the vortices decay as the cyclonic vorticity source provided by the initial vortex is depleted and negative vorticity surrounding the vortex core is drawn inwards by the convectively driven overturning circulation. In these negative vorticity regions, the flow is inertially/centrifugally unstable. The vortex evolution during the mature and decay phases differs from that in simulations away from the Equator, where inertially unstable regions are much more limited in area. Vortex decay in the simulations appears to be related intimately to the development of inertial instability, which is accompanied by an outward‐propagating band of deep convection. The degree to which this band of deep convection is realistic is unknown