Search

Negative-pressure-wound-therapy is commonly used in clinical routine for wound management. Aim of the present study was to assess the feasibility and safety of using an additional container to collect wound fluid during ongoing negative-pressure-wound-therapy. In this present prospective observational study, patients with negative-pressure-wound-therapy were included. An additional container was inserted in the connecting tube between the wound and the vacuum generating device. The following 3 days, the container was changed daily and replaced by a new one. Further safety outcome parameters were assessed. A questionnaire was answered by the responsible surgeon. Twenty-two patients with negative-pressure-wound-therapy with a median (IQR) age of 58.5 (53.0-70.0) years were included in the present study. In median, the duration of negative-pressure-wound-therapy was 5.0 (4.6-5.5) days. In mean ± SD the collected volume of the wound fluid in millilitres (mL) was on day one 7 ± 4 on day two 8 ± 7 and 10 ± 11 on day three. In one patient, there was0.1 mL of clear water in the additional container. No safety concerns due to the additional container were observed. This study demonstrates that collecting wound fluid during ongoing negative-pressure-wound-therapy over a time period of 3 days is feasible and safe. No safety concerns were observed.

Contains fulltext : 169936.pdf (Publisher’s version ) (Open Access) AAA-ATPases fulfil essential roles in different cellular pathways and often act in form of hexameric complexes. Interaction with pathway-specific substrate and adaptor proteins recruits them to their targets and modulates their catalytic activity. This substrate dependent regulation of ATP hydrolysis in the AAA-domains is mediated by a non-catalytic N-terminal domain. The exact mechanisms that transmit the signal from the N-domain and coordinate the individual AAA-domains in the hexameric complex are still the topic of intensive research. Here, we present the characterization of a novel mutant variant of the eukaryotic AAA-ATPase Drg1 that shows dysregulation of ATPase activity and altered interaction with Rlp24, its substrate in ribosome biogenesis. This defective regulation is the consequence of amino acid exchanges at the interface between the regulatory N-domain and the adjacent D1 AAA-domain. The effects caused by these mutations strongly resemble those of pathological mutations of the AAA-ATPase p97 which cause the hereditary proteinopathy IBMPFD (inclusion body myopathy associated with Paget's disease of the bone and frontotemporal dementia). Our results therefore suggest well conserved mechanisms of regulation between structurally, but not functionally related members of the AAA-family.

In this study we investigated the ability of amidases to hydrolyse polyurethane polyester co-polymers. In order to improve enzyme adsorption, a polyamidase from Nocardia farcinica (PA) was fused to a polymer binding module from a polyhydroxyalkanoate depolymerase from Alcaligenes faecalis (PA_PBM). The activity of these enzymes and of various commercially available amidases on a synthesized soluble model substrate was compared. The recombinant native PA showed the highest activity of 10.5 U/mg followed by PA_PBM with an activity of 1.13 U/mg. Both enzymes were able to cleave the urethane bond in polyurethane-polyesters with different degree of crystallinity as shown by FTIR. According to LC-TOF analysis the monomer 4,4′-diaminodiphenylmethane (MDA) and the oligomers 4-hydroxybutyl (3-(3-aminobenzyl)phenyl)carbamate [B], bis(4-hydroxybutyl) (methylenebis(3,1-phenylene))dicarbamate [C] and 4-(((3-(3-(((4-hydroxybutoxy)carbonyl)amino)benzyl)phenyl)carbamoyl)oxy)butyl (4-hydroxybutyl) adipate [D] were released. The polymer with a higher content of the rigid segment, MDA, was hydrolysed to a lower extent. Interestingly, despite the lower activity on the soluble model substrate, the PA_PBM fusion enzyme was up to 4 times more active on the polymer when compared with the native enzyme, confirming the relevance of enzyme adsorption for efficient hydrolysis.

There is a strong need for new point-of-care systems for the detection of wound infection. Overseen infections in chronic wounds induce severe complications, such as delayed healing and high risks for the patients, while time-consuming common gold and silver standard methods for infection assessment cannot be implemented in home care units. This study demonstrates for the first time the between correlation of lysozyme activity and silver-standard microbiological evaluation of wounds. Significantly higher (eightfold increase; p < 0.001) lysozyme activity in infected wounds was in accordance with increasing bacterial burden of infected wound fluids. Moreover, a two-layer membrane-based test system was developed providing visible results on infection in a short time (30 min) while avoiding any intermediate steps such as centrifugation. In the first layer of the system, a size exclusion membrane (1.2-8 μm cut-off) retained labeled peptidoglycane while allowing only smaller fragments resulting from lysozyme hydrolysis to pass through. These fragments were then captured in a second layer, an anion-exchanging diethylaminoethyl cellulose membrane, resulting in clearly visible color changes. Colorimetric measurements demonstrated significant differences (p < 0.001) and sixfold higher delta E values between infected and noninfected wound fluids. This system allows a quick and straightforward determination of the status of a wound. The colorimetric readout indicates the increased lysozyme activity in infected wound fluid.