Damage control orthopaedics in polytraumatized patients- current concepts

The principles of fracture management in patients with multiple injuries continue to be of crucial importance. Early treatment of unstable polytraumatized patients with head, chest, abdomen or pelvic injuries, with blood loss followed by immediate fracture fixation (Early Total Care -ETC) may be associated with secondary life threatening posttraumatic systemic inflammatory response syndrome (SIRS). Development of SIRS is typically a function of the type and severity of the initial injury (the “first hit”). Immediate Fracture fixation, using reamed nails or plates, in such unstable patients with multiple injuries is subsequently defined as the “second hit” and may be associated with development of acute respiratory distress syndrome (ARDS) and multiple organ failure (MOF), with relatively high morbidity and mortality.The other alternative for long bone fracture fixation in unstable polytraumatized patients is based on immediate treatment of life threatening conditions related to the injuries, followed by the initial use of minimally invasive modular external frames for long bone fractures and is called Damage Control Orthopedics (DCO) and is widely accepted. In order to refine the DCO concept and to avoid an overuse of external fixation, the “Safe Definitive Surgery” (SDS) concept has been introduced, which is a dynamic synthesis of both strategies (ETC and DCO). The SDS strategy employs clinical parameters and includes repeated assessment of patients. The following paper is going to summarize historical backgrounds and recent concepts in treatment of polytraumatized patients.     

Autologous adult rodent neural progenitor cell transplantation represents a feasible strategy to promote structural repair in the chronically injured spinal cord

Adult neural progenitor cells (NPCs) represent an attractive source for cell-based regenerative strategies in CNS disease. In animal models of spinal cord injury, syngenic adult NPCs, which were isolated from pooled post-mortem CNS tissue and co-transplanted together with fibroblasts, have been shown to promote substantial structural repair. The autologous transplantation of adult NPCs represents a major advantage compared with other sources of neural stem/progenitor cells. However, the feasibility of autologous NPC generation from a single biopsy in a relevant preclinical CNS disease model has yet to be demonstrated. To investigate this matter, adult Wistar rats underwent a cervical spinal cord lesion, which was followed by a minimal subventricular zone aspiration biopsy 2 days later. NPCs were isolated and propagated separately for each animal for the following 8 weeks. Thereafter, they were co-transplanted with simultaneously harvested skin fibroblasts in an autologous fashion into the cervical spinal cord lesion site. A total of 4 weeks later, graft survival, tissue replacement and axonal regeneration were assessed histologically. Animals receiving either allogenic NPCs combined with fibroblasts or autologous pure fibroblast grafts served as control groups. Within 8 weeks after the biopsy more than 3 million NPCs could be generated from a single aspiration biopsy, which displayed a differentiation pattern indistinguishable from syngenic NPC grafts. NPCs within autologous co-grafts readily survived, replaced cystic lesion defects completely and differentiated exclusively into glial phenotypes, thus paralleling previous findings with syngenic NPCs. The delayed transplantation 8 weeks after the spinal cord lesion elicited substantial axonal regeneration. These findings demonstrate that the therapeutic strategy to induce structural repair by transplanting adult autologous NPCs, after the successful propagation from a small brain biopsy into an acute CNS disease model, such as spinal cord injury, is feasible at the preclinical level.     

From the Cover: Brain signatures of artificial language processing: Evidence challenging the critical period hypothesis

Adult second language learning seems to be more difficult and less efficient than first language acquisition during childhood. By using event-related brain potentials, we show that adults who learned a miniature artificial language display a similar real-time pattern of brain activation when processing this language as native speakers do when processing natural languages. Participants trained in the artificial language showed two event-related brain potential components taken to reflect early automatic and late controlled syntactic processes, whereas untrained participants did not. This result challenges the common view that late second language learners process language in a principally different way from native speakers. Our findings demonstrate that a small system of grammatical rules can be syntactically instantiated by the adult speaker in a way that strongly resembles native-speaker sentence processing.     

Viral gene transfer for xenotransplantation

In order to overcome the major immunological barriers to xenotransplantation, genetic strategies have to be developed that ensure long‐term engraftment of the organ. To this end, immune‐modulatory transgenes have to be efficiently expressed and/or the expression of xeno‐relevant porcine genes (xeno‐epitopes) has to be silenced. Viral vectors are powerful tools for modulating expression of foreign genes in organs and even the whole animal. Using lentiviral gene transfer in early embryos, gain‐of‐function models can be generated with high efficacies in pig (lentiviral transgenesis). Through combination of lentiviral transgenesis and RNA interference (RNAi) loss‐of‐function models for xenotransplantation can be generated. Our goal is to combine lentivector‐mediated RNAi directed against α‐galactosyltransferase (α‐GT) with immune‐modulatory approaches to finally generate multitransgenic pigs. Furthermore, sensitivity to human serum inactivation of porcine endogenous retrovirus produced by pig cells with reduced levels of α‐GT expression was analysed.     

Perforation eines mucocelenartig transformierten Hartmannstumpfs

We report an unusual complication in a 53-year-old woman following ileostomy for Crohn's disease 22 years previously. A stenosis of the distal colonic segment was the reason for the formation and subsequent rupture of a huge colonic mucocele. To our knowledge, this is the first report of a ruptured mucocele of colonic origin after ileostomy.     

A computer assisted comparison of 99Tcm-methylene-diphosphonate and 99Tcm-pyrophosphate bone imaging.

A total of 350 patient studies were carried out using clinical trials' batches of the Technetium (MDP) agent for bone scintigraphy (The Radiochemical Centre), and a commercially available Technetium pyrophosphate agent (CIS). The bone seeking properties of 99Tcm Sn-methylene-diphosphonate (MDP) and 99Tcm Sn-pyrophosphate (PYP) were evaluated by their comparative uptake in compact bone, cancellous bone and soft tissue using a region-of-interest technique. From these data uptake ratios were computed in order to correlate the values with (a) the amount of 99Tcm-MDP injected, (b) the time after injection and (c) the age of patients examined. All ratios derived with 99Tcm-MDP were superior to those using 99Tcm-PYP and were not dependent on the amount of 99Tcm-MDP injected. Uptake ratios determined for 99Tcm-MDP (1.5 h to 2.5 h after injection) were found to be higher than those for 99Tcm-PYP 2.5 to 3.5 h after injection. Soft tissue accumulation of 99Tcm-MDP, visible on scintiphotos, occurred only in 26% of cases but with 99Tcm-PYP, in 75% out of all cases studied. A decrease of cancellous bone/compact bone ratios with increasing age of the patients was found with both radiopharmaceuticals. This is most probably correlated with a diminished mass and/or surface of the cancellous bone in the elderly patient.