Rapid metabolism fosters microbial survival in the deep, hot subseafloor biosphere.

A fourth of the global seabed sediment volume is buried at depths where temperatures exceed 80 °C, a previously proposed thermal barrier for life in the subsurface. Here, we demonstrate, utilizing an extensive suite of radiotracer experiments, the prevalence of active methanogenic and sulfate-reducing populations in deeply buried marine sediment from the Nankai Trough subduction zone, heated to extreme temperature (up to ~120 °C). The small microbial community subsisted with high potential cell-specific rates of energy metabolism, which approach the rates of active surface sediments and laboratory cultures. Our discovery is in stark contrast to the extremely low metabolic rates otherwise observed in the deep subseafloor. As cells appear to invest most of their energy to repair thermal cell damage in the hot sediment, they are forced to balance delicately between subsistence near the upper temperature limit for life and a rich supply of substrates and energy from thermally driven reactions of the sedimentary organic matter.

Complex Microbial Communities Drive Iron and Sulfur Cycling in Arctic Fjord Sediments.

Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in low-organic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (∼5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by δ13C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron- and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf.IMPORTANCE Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.

Cryptic CH4 cycling in the sulfate-methane transition of marine sediments apparently mediated by ANME-1 archaea.

Methane in the seabed is mostly oxidized to CO2 with sulfate as the oxidant before it reaches the overlying water column. This microbial oxidation takes place within the sulfate-methane transition (SMT), a sediment horizon where the downward diffusive flux of sulfate encounters an upward flux of methane. Across multiple sites in the Baltic Sea, we identified a systematic discrepancy between the opposing fluxes, such that more sulfate was consumed than expected from the 1:1 stoichiometry of methane oxidation with sulfate. The flux discrepancy was consistent with an oxidation of buried organic matter within the SMT, as corroborated by stable carbon isotope budgets. Detailed radiotracer experiments showed that up to 60% of the organic matter oxidation within the SMT first produced methane, which was concurrently oxidized to CO2 by sulfate reduction. This previously unrecognized "cryptic" methane cycling in the SMT is not discernible from geochemical profiles due to overall net methane consumption. Sedimentary gene pools suggested that nearly all potential methanogens within and beneath the SMT belonged to ANME-1 archaea, which are typically associated with anaerobic methane oxidation. Analysis of a metagenome-assembled genome suggests that predominant ANME-1 do indeed have the enzymatic potential to catalyze both methane production and consumption.

Control on rate and pathway of anaerobic organic carbon degradation in the seabed.

The degradation of organic matter in the anoxic seabed proceeds through a complex microbial network in which the terminal steps are dominated by oxidation with sulfate or conversion into methane and CO2 The controls on pathway and rate of the degradation process in different geochemical zones remain elusive. Radiotracer techniques were used to perform measurements of sulfate reduction, methanogenesis, and acetate oxidation with unprecedented sensitivity throughout Holocene sediment columns from the Baltic Sea. We found that degradation rates transition continuously from the sulfate to the methane zone, thereby demonstrating that terminal steps do not exert feedback control on upstream hydrolytic and fermentative processes, as previously suspected. Acetate was a key intermediate for carbon mineralization in both zones. However, acetate was not directly converted into methane. Instead, an additional subterminal step converted acetate to CO2 and reducing equivalents, such as H2, which then fed autotrophic reduction of CO2 to methane.

Behaviour change: Trialling a novel approach to reduce industrial stormwater pollution.

The evidence base for the performance and effectiveness of non-structural measures to manage stormwater pollution in industrial areas is relatively underdeveloped, despite their increased use in practice. This study aims to advance stormwater management practice and research by presenting a detailed case study of the development, implementation and evaluation of a targeted behaviour change trial that engaged small to medium industrial businesses in stormwater pollution prevention. Utilising a combination of different behaviour change strategies - including capacity building, social norms and commitment - a number of preventative stormwater pollution behaviours were changed in participating businesses. Our study provides a practice model for tackling stormwater pollution from a behavioural perspective that can be further developed by both practitioners and researchers to create effective and long-lasting change.

The Diabetic Foot in a Multidisciplinary Team Setting. Number of Amputations below Ankle Level and Mortality.

Aim: To describe the number of minor lower extremity amputations and mortality for diabetes patients treated by a specialized multidisciplinary foot care team. Methods: A retrospective descriptive study of medical records from patients with diabetes treated with minor amputations at the Copenhagen Wound Healing Center (CWHC) at Bispebjerg Hospital from 1996-2013. Results: 777 diabetes patients treated with minor amputations were included. 77% were males and 23% were females. 80% had T2 diabetes and 20% had T1 diabetes. 89% of the patients had a foot ulcer at first contact. There was a total of 1 231 minor amputations. The amputations were mainly trans-metatarsal amputations and partial amputations of toes. There was an increase in the number of minor amputations, but there was also an increase in the number of referred diabetes patients, thus the ratio of amputations per admitted diabetes patient was constant. Time from first amputation to death was 2.5 years. The 5-year mortality rate was 43% and 52% for T1 and T2 diabetes patients, respectively. Conclusion: Due to increased number of referred diabetes patients, the number of diabetes patients undergoing minor amputations increased over the years. Patients with diabetes, who underwent minor amputation, had a high mortality averaging 2.5 year to death; comparable to many types of cancer.

Effects of using the simplified airway risk index vs usual airway assessment on unanticipated difficult tracheal intubation - a cluster randomized trial with 64,273 participants.

BACKGROUND: Unanticipated difficult intubation remains a challenge in anaesthesia. The Simplified Airway Risk Index (SARI) is a multivariable risk model consisting of seven independent risk factors for difficult intubation. Our aim was to compare preoperative airway assessment based on the SARI with usual airway assessment. METHODS: From 01.10.2012 to 31.12.2013, 28 departments were cluster-randomized to apply the SARI model or usual airway assessment. The SARI group implemented the SARI model. The Non-SARI group continued usual airway assessment, thus reflecting a group of anaesthetists' heterogeneous individual airway assessments. Preoperative prediction of difficult intubation and actual intubation difficulties were registered in the Danish Anaesthesia Database for both groups. Patients who were preoperatively scheduled for intubation by advanced techniques (e.g. video laryngoscopy; flexible optic scope) were excluded from the primary analysis. Primary outcomes were the proportions of unanticipated difficult and unanticipated easy intubation. RESULTS: A total of 26 departments (15 SARI and 11 Non-SARI) and 64 273 participants were included. In the primary analyses 29 209 SARI and 30 305 Non-SARI participants were included.In SARI departments 2.4% (696) of the participants had an unanticipated difficult intubation vs 2.4% (723) in Non-SARI departments. Odds ratio (OR) adjusted for design variables was 1.03 (95% CI: 0.77-1.38). The proportion of unanticipated easy intubation was 1.42% (415) in SARI departments vs 1.00% (302) in Non-SARI departments. Adjusted OR was 1.26 (0.68-2.34). CONCLUSIONS: Using the SARI compared with usual airway assessment we detected no statistical significant changes in unanticipated difficult- or easy intubations. CLINICAL TRIAL REGISTRATION: NCT01718561.

Use of an autologous leucocyte and platelet-rich fibrin patch on hard-to-heal DFUs: a pilot study.

OBJECTIVE: Leucopatch is a leukocyte and platelet-rich fibrin patch that provides concentrated blood cells and signal substances to the surface of an ulcer. It is produced by centrifugation of the patient's own venous blood. The aim of this pilot multicentre cohort study was to evaluate effects of the leucocyte patch in patients with hard-to-heal diabetic foot ulcers (DFUs). METHOD: Non-ischaemic Wagner grade 1 or 2 DFUs with a duration of more than 6 weeks and a maximal area of 10cm² were included. Patients with >40% ulcer area change during a two-week run-in period were excluded. The treatment was applied once a week for up to 19 treatments or until the foot ulcer was completely epithelialised. The primary endpoint was healing within 20 weeks. RESULTS: Of the 60 patients who gave consent 16 were excluded during run-in period, 44 patients initiated study treatment and 39 were included in the per-protocol analysis. Complete epithelisation was achieved in 34% (per-protocol analysis 36%) at 12 weeks and 52% (59%) at 20 weeks. In patients with ulcer duration less than 6 months, 73% of ulcers healed within 20 weeks. Patients with healed ulcers had larger ulcer area reduction during the first two treatment weeks compared to non-healers. Adverse events were mild and rare. CONCLUSION: The leucocyte patch is well-tolerated, easy to use and has potential in the armamentarium of the DFU treatment, provided this outcome is confirmed in an appropriately powered randomised clinical trial.

Investigating the long-term effect of subchronic phencyclidine-treatment on novel object recognition and the association between the gut microbiota and behavior in the animal model of schizophrenia.

Subchronic phencyclidine (subPCP) treatment induces schizophrenic-like behavior in rodents, including cognitive deficits and increased locomotor sensitivity towards acute administration of PCP. Evidence is accumulating that the gut microbiota (GM) influences behavior through modulation of the microbiota-gut-brain axis, and hence, part of the variation within this animal model may derive from variation in the GM. The aims of this study was to investigate first, the duration of subPCP-induced cognitive impairment in the novel object recognition test, and second, the possible effect of subchronic PCP-treatment on the GM, and the association between the GM and the behavioral parameters. The association was further investigated by antibiotic reduction of the GM. Male Lister Hooded rats were dosed twice daily i.p. with either 5mg/kg PCP or sterile isotonic saline for seven days followed by a seven-day washout period. Rats were tested in the novel object recognition and the locomotor activity assays immediately after, three weeks after, or six weeks after washout, and the fecal GM was analyzed by high throughput sequencing. Antibiotic- and control-treated rats were tested in the same manner following washout. In conclusion, subPCP-treatment impaired novel object recognition up to three weeks after washout, whereas locomotor sensitivity was increased for at least six weeks after washout. Differences in the core gut microbiome immediately after washout suggested subPCP treatment to alter the GM. GM profiles correlated to memory performance. Administration of ampicillin abolished the subPCP-induced memory deficit. It thus seems reasonable to speculate that the GM influences memory performance, contributing to variation within the model.

Growth factor and proteinase profile of Vivostat® platelet-rich fibrin linked to tissue repair.

BACKGROUND AND OBJECTIVES: Autologous platelet-rich fibrin (PRF(®)) is prepared by the automatic Vivostat(®) system. Conflicting results with Vivostat PRF in acute wound healing prompted us to examine its cellular and biomolecular composition. Specifically, platelets, selected growth factors and matrix metalloproteinase (MMP)-9 were quantified using novel analytical methods. MATERIALS AND METHODS: Ten healthy non-thrombocytopenic volunteers donated blood for generation of intermediate fibrin-I and final PRF. Anticoagulated whole blood and serum procured in parallel served as baseline controls. Leucocyte, erythrocyte and platelet counts in whole blood and fibrin-I were determined by automated haematology analyser. Platelet concentration in PRF was quantified manually by stereologic analysis of Giemsa-stained tissue sections, and the total content of five growth factors and MMP-9 by enzyme-linked immunosorbent assays. RESULTS: The number of leucocytes and erythrocytes was reduced (P < 0·001), whereas platelets increased (P < 0·001) in fibrin-I versus whole blood. PRF contained 982 ± 206 × 10(9) platelets/l representing 3·9-fold (P < 0·001) enrichment relative to whole blood. Growth factor abundance in Vivostat PRF and serum was in descending order: transforming growth factor-ß1 [5·1-fold higher in PRF than serum, P < 0·001] > platelet-derived growth factor (PDGF)-AB [2·5-fold, P < 0·01] > PDGF-BB [1·6-fold, P < 0·05] > vascular endothelial growth factor > basic fibroblast growth factor [75-fold, P < 0·001]. MMP-9 was reduced 139-fold (P < 0·001) compared with serum, reflecting leucocyte depletion in PRF. CONCLUSION: The gained knowledge on platelet enrichment and biomolecular constituents may guide clinicians in their optimal use of Vivostat PRF for tissue regenerative applications.

Nephrogenic systemic fibrosis is found only among gadolinium-exposed patients with renal insufficiency: a case-control study from Denmark.

BACKGROUND: Nephrogenic systemic fibrosis (NSF) is a systemic fibrosing disease associated with exposure to gadolinium-based contrast agents (GBCA) in patients with renal insufficiency. OBJECTIVES: To report the prevalence of NSF in a well-defined cohort of patients with renal insufficiency exposed to GBCA, to investigate if GBCA-unexposed controls showed signs of NSF and to evaluate selected risk factors among NSF cases and GBCA-exposed controls. METHODS: A study among GBCA-exposed patients with renal insufficiency (n=565) was conducted to identify cases of NSF. The NSF cases found were age and sex matched and clinically compared with GBCA-exposed and unexposed patients with renal insufficiency in a case-control study. RESULTS: We identified 17 NSF cases. No signs of NSF were observed among the controls. The prevalence of NSF was 4·7%, highest among patients with chronic kidney disease (CKD) stage 5 exposed to GBCA and undergoing haemodialysis or peritoneal dialysis. Three NSF cases were identified among patients with CKD stage 3 and 4. Three patients developed NSF after macrocyclic GBCA exposure. NSF cases had a tendency to have higher serum phosphate concentrations than GBCA-exposed controls. CONCLUSIONS: Our study supports the view that GBCA is a major risk factor for NSF. Importantly, we found that patients with CKD stage 3 and 4 can be at risk of NSF. NSF may also be triggered by macrocyclic GBCA. Further, we observed a trend for higher phosphate levels in NSF cases compared with controls. The important findings drawn from this case-control study indicate that NSF is not an overlooked condition among patients with renal insufficiency not exposed to GBCA.

Perisciatic infusion of ropivacaine and analgesia after hallux valgus repair.

BACKGROUND: Moderate to severe pain after hallux valgus repair can be successfully treated with a continuous popliteal sciatic nerve block in ambulatory patients. Different anesthesiologists use various infusion rates for this purpose. The aim of this study was to compare the analgesic efficacy of two infusion rates of ropivacaine 2 mg/ml: 5 and 8 ml/h. METHODS: Forty ambulatory patients who underwent chevron osteotomy for hallux valgus were randomized to receive perisciatic infusion of ropivacaine 2 mg/ml at a rate of either 5 ml/h (5 ml group) or 8 ml/h (8 ml group). All patients received standard general anesthesia for surgery after the sciatic popliteal and the single-shot saphenus nerve blocks were performed. Verbal rating scale (VRS) scores for pain, sleep disturbances, opioid consumption and side effects were monitored for 3 post-operative days. RESULTS: No significant difference was found in the primary end point worst pain on the first post-operative day with VRS scores of 2.5 (0-8) vs. 5.5 (0-10) for the 5 and 8 ml/h groups, respectively (P=0.53). Post-operative pain was satisfactory in both groups, with an average VRS score ≤4 for 60-62 h. CONCLUSION: We found no significant difference in the analgesic effect between two perisciatic infusion rates of ropivacaine 2 mg/ml (5 vs. 8 ml/h) in ambulatory patients who underwent chevron osteotomy.

Depth of anaesthesia monitoring in obese patients: a randomized study of propofol-remifentanil.

BACKGROUND: In obese patients, depth of anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that depth of anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil. METHODS: We investigated 38 patients with a body mass index >or=30 kg/m(2) scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer. RESULTS: Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group (P=0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h (P=0.24) and for remifentanil 2393 vs. 2708 microg/h (P=0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight. CONCLUSION: No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.

Caring for patients with difficult-to-heal ulcers.

This article presents Coloplast's chronic wound care guide for community nurses, in which wound management is described in terms of assessment, treatment and reassessment. Choosing the optimal wound dressing is explained separately. Three case studies are used to demonstrate the use of the guide. Using the guide as a framework is straightforward and easily interpreted by health professionals with varying levels of wound care knowledge and experience, therefore enabling health care professionals to use evidence based practice to improve patient outcomes.

Combined use of an ibuprofen-releasing foam dressing and silver dressing on infected leg ulcers.

OBJECTIVE: To investigate the effect and safety of an ibuprofen-releasing foam (Biatain-Ibu, Coloplast A/S) combined with an ionised silver-releasing wound contact layer (Physiotulle Ag, Coloplast A/S) on painful, infected venous leg ulcers. METHOD: This open non-comparative study involved 24 patients with painful, exuding, locally infected, and stalled venous leg ulcers. Persistent pain and pain at dressing change were monitored using a 11-point numerical box scale (NBS). The composition of the wound bed, the dressing combination's ability to absorb exudate and minimise leakage, ibuprofen content in the exudate, reduction in wound area and adverse effects were also recorded. RESULTS: Persistent wound pain decreased from a mean of 6.3 +/- 2.2 to 3.0 +/- 1.7 after 12 hours and remained low thereafter. Pain at dressing change also decreased and remained low. Forty-eight hours after the first dressing application, the mean concentration of ibuprofen in the wound exudate reached a constant level of 35 +/- 21 microg/ml. After 31 days, the relative wound area had reduced by 42%, with an associated decrease in fibrin and an increase in granulation tissue. The number of patients with wound malodour decreased from 37% to 4%. No serious adverse events were reported. CONCLUSION: The combined use of the ibuprofen-releasing foam dressing and silver-releasing contact layer reduced wound pain and promoted healing without compromising safety.

Bacterial profiling using skin grafting, standard culture and molecular bacteriological methods.

OBJECTIVE: Wound healing can be delayed by the presence of colonising bacteria, and in polymicrobial wounds they may act synergistically to the further detriment of wound healing. In this pilot investigation, biopsy and swab samples were obtained as part of skin-graft operations performed on a chronic venous leg ulcer in order to study the spatial microbial diversity and to compare standard bacteriological and molecular biological techniques. METHOD: The wound was sampled before excision, and sampling was undertaken at multiple locations across the wound. Swab samples and biopsies were subjected to culture analysis and 16S rRNA polymerase chain reaction (PCR), and to denaturing gradient gel electrophoresis (DGGE). RESULTS: Within the wound samples, DGGE identified the major wound microflora components and established the extent of local differences in bacterial diversity. CONCLUSION: This ongoing investigation has verified DGGE as a powerful tool for elucidating the clinical microbiology of a chronic disease state. It also suggests that skin graft operations are a novel way of obtaining multiple samples for in vivo bacteriology and for establishing the spatial distribution of bacteria in the complex micro-environment of chronic wounds.

Biomechanical gait analysis of pigs walking on solid concrete floor.

Inappropriate floors in pig pens and slippery floor conditions may cause leg problems that reduce animal welfare. Therefore the objectives of the present study were to characterise the walk of pigs on dry concrete solid floor, to evaluate whether pigs modify their gait according to floor condition, and to suggest a coefficient of friction (COF) that ensures safe walking on solid concrete floors for pigs. Kinematic (50 Hz video recordings in the sagittal plane) and kinetic (1 KHz force plate measuring three perpendicular ground reaction forces) data were collected from four strides of both the fore- and hindlimbs of 30 healthy pigs walking on dry, greasy and wet concrete floor with 10 pigs on each floor condition. The COF of the floor conditions were tested in a drag-test. The results from the gait analysis showed that the pigs adapted their gait to potentially slippery floors by lowering their walking speed and reducing their peak utilised COF on greasy and wet (contaminated) floors compared with dry floors. Moreover, the pigs shortened their progression length and prolonged their stance phase duration on greasy floor compared with dry and wet floors. Thus the greasy floor appeared the most slippery condition to the pigs, whereas the wet floor was intermediate to the other two conditions. The pigs walked with a four-beat gait, and the limbs differed biomechanically, as the forelimbs carried more load, received higher peak vertical forces and had longer lasting stance phases than did the hindlimbs. The utilised COF from the gait analysis indicated that a high floor COF (>0.63) is needed to prevent pigs from slipping and thus to ensure safe walking on dry concrete floors.

Effect of a new silver dressing on chronic venous leg ulcers with signs of critical colonisation.

OBJECTIVE: To investigate the clinical performance and safety of a new silver-containing wound-contact layer, Physiotulle -Ag (Coloplast), in the treatment of chronic venous leg ulcers with delayed healing and signs of critical colonisation. METHOD: This was an open prospective non-comparative multicentre clinical study. Patients were treated for four weeks with Physiotulle -Ag, which was covered by Alione Hydrocapillary Dressing (Coloplast). RESULTS: Thirty patients were recruited into the study. One ulcer healed after three weeks of treatment. The mean relative ulcer area reduced by 55% after four weeks. Over the study period the mean amount of healthy granulation tissue increased from 26% to 62%, and the mean amount of fibrin decreased from 63% to 32%. The ratio of malodorous wounds was 50% at inclusion, 20% after one week and 3% after four weeks. The dressing was considered easy or very easy to apply in 100% and easy to remove in 89% of dressing evaluations. The dressing combination showed good exudate-management properties. Incidence and severity of maceration, erythema and eczema decreased during the study and no device-related adverse events were recorded. CONCLUSION: Physiotulle -Ag is safe and easy to use in chronic venous leg ulcers in which healing is delayed and with signs of critical colonisation.

Control of fibronectin displacement on polymer substrates to influence endothelial cell behaviour.

Thin layered biomaterial surfaces of maleic anhydride copolymers are provided as a versatile platform for biomaterial applications. The provided comonomers define the character of the surface and its behaviour towards biomolecules and biosystems, such as proteins and cells. The kinetics of adsorption, desorption, and exchange of fibronectin and human serum albumin were investigated on different copolymer surfaces. Two different species of adsorbed proteins were found, a fast and a slow desorbing one. Furthermore, the exchange process depends on the kind of pre-adsorbed protein and the kind of exchange protein, as well as of the hydrophobicity of the copolymer surface. In this context adhesion, proliferation, and differentiation of endothelial cells from the umbilical cord vein onto fibronectin pre-coated surfaces were studied. Strong correlation between fibronectin exchange characteristics and the formation of focal adhesions, reorganisation of fibronectin, and generation of vascular-like structures by the cells was observed.