Murine scald models characterize the role of neutrophils and neutrophil extracellular traps in severe burns.

Introduction: Severe burns cause unique pathophysiological alterations especially on the immune system. A murine scald model was optimized as a basis for the understanding of immunological reactions in response to heat induced injury. The understanding of the roles of neutrophil extracellular traps (NETs) and DNases will support the development of new surgical or pharmacological strategies for the therapy of severe burns. Methods: We studied C57BL/6 mice (n=30) and employed four scalding protocols with varying exposure times to hot water. An additional scald group with a shorter observational time was generated to reduce mortality and study the very early phase of pathophysiology. At 24h or 72h, blood was drawn and tissue (wound, liver, lung, spleen) was analyzed for the presence of NETs, oxidative stress, apoptosis, bacterial translocation, and extracellular matrix re-organization. In addition, we analyzed the transcriptome from lung and liver tissues. Results: Exposure to hot water for 7s led to significant systemic and local effects and caused considerable late mortality. Therefore, we used an observation time of 24h in this groups. To study later phases of burns (72h) an exposure time of 6s is optimal. Both conditions led to significant disorganization of collagen, increased oxidative stress, NET formation (by immunodetection of H3cit, NE, MPO), apoptosis (cC3) and alterations of the levels of DNase1 and DNase1L3. Transcriptome analysis revealed remarkable alterations in genes involved in acute phase signaling, cell cohesion, extracellular matrix organization, and immune response. Conclusion: We identified two scald models that allow the analysis of early (24h) or late (72h) severe burn effects, thereby generating reproducible and standardized scald injuries. The study elucidated the important involvement of neutrophil activity and the role of NETs in burns. Extensive transcriptome analysis characterized the acute phase and tissue remodeling pathways involved in the process of healing and may serve as crucial basis for future in-depth studies.

Factors Influencing Performance in Laparoscopic Suturing and Knot Tying: A Cohort Study.

BACKGROUND: Laparoscopic suturing and knot tying are regarded as some of the most difficult laparoscopic skills to learn. Training is essential to reach proficiency, but available training opportunities are limited. Various techniques to improve training have been evaluated. It appears that individual-related factors affect initial performance and response to training. Thus, the current study aimed to assess factors influencing laparoscopic-suturing and knot-tying performances. METHODS: All patients were trained one-on-one (teacher-student) for 3 hours. Patients were tested before training (bowel anastomosis model) and directly after training (congenital diaphragmatic hernia or esophageal atresia model) to evaluate transferability. Primary endpoints were time, knot quality, precision, knot strength, and overall laparoscopic knotting performance. Moreover, factors such as (1) age, (2) gender, (3) handedness, (4) previous training or operative experience, (5) playing an instrument, (6) sportive activities, and (7) computer gaming which may influence the primary endpoints were assessed. RESULTS: In total, 172 medical students or novice surgical residents were included. Training significantly improved all outcome parameters assessed in the current study. More than 50% of the patients reached proficiency after 3 hours of training. Personal factors like operative experience, playing music instruments, sportive activities, and computer gaming affected some outcome parameters. Handedness and gender affected initial performance but differences partially subsided after training. Younger participants showed a much better response to training. CONCLUSION: In conclusion, several factors influence initial performance and response to the training of laparoscopic suturing and knot tying. Surgeons who want to improve their laparoscopic performance, should concentrate on playing a musical instrument and performing sports rather than playing videos gaming. It appears that training is a key and more practice opportunities should be incorporated into medical school and surgical curricula. Moreover, handedness may affect the outcome but only if the training concepts are not tailored to the dominant hand of the surgeon. Future training and surgical curricula should adapt to this and tailor their concepts accordingly.

cfDNA and DNases: New Biomarkers of Sepsis in Preterm Neonates-A Pilot Study.

INTRODUCTION: An early and accurate diagnosis of early onset neonatal sepsis (EONS) and late onset neonatal sepsis (LONS) is essential to improve the outcome of this devastating conditions. Especially, preterm infants are at risk. Reliable biomarkers are rare, clinical decision-making depends on clinical appearance and multiple laboratory findings. Markers of NET formation and NET turnover might improve diagnostic precision. Aim of this study was to evaluate the diagnostic value of NETs in sepsis diagnosis in neonatal preterm infants. METHODS: Plasma samples of neonatal preterm infants with suspected sepsis were collected. Blood samples were assayed for markers of NET formation and NET turnover: cfDNA, DNase1, nucleosome, NE, and H3Cit. All clinical findings, values of laboratory markers, and epidemiological characteristics were collected retrospectively. Two subpopulations were created to divide EONS from LONS. EMA sepsis criteria for neonatal sepsis were used to generate a sepsis group (EMA positive) and a control group (EMA negative). RESULTS: A total of 31 preterm neonates with suspected sepsis were included. Out of these, nine patients met the criteria for sepsis according to EMA. Regarding early onset neonatal sepsis (3 EONS vs. 10 controls), cfDNA, DNase I, nucleosome, and CRP were elevated significantly. H3Cit and NE did not show any significant elevations. In the late onset sepsis collective (6 LONS vs. 12 controls), cfDNA, DNase I, and CRP differed significantly compared to control group.