Herwig Ainoedhofer

Analysis of dog bites in children who are younger than 17 years

OBJECTIVES. This study focuses on the pattern of incidence, mechanisms, and circumstances of accident and injury in a series of pediatric patients who sustained dog bites. METHODS. In our retrospective survey, the medical charts of all children who were younger than 17 years and sought medical attention after a dog bite between 1994 and 2003 were reviewed. To obtain the total number of each dog breed in the administrative district, we analyzed 5873 files from the community dog registers. For establishment of a risk index, the representation of a dog breed among the total canine population was divided by the frequency of dog bites from this breed. RESULTS. A total of 341 children (mean age: 5.9 years) were identified. The annual incidence of dog bites was 0.5 per 1000 children between 0 and 16 years of age. Incidence was highest in 1-year-old patients and decreased with increasing age. The relative risk for a dog attack by a German shepherd or a Doberman was ∼5 times higher than that of a Labrador/retriever or cross-breed. The vast majority (82%) of the dogs were familiar to the children. Most (322; 94%) of the children had injuries to 1 body region; in the remaining 19 (6%) children, up to 3 body regions were injured. Of 357 injuries, the face, head, and neck region was the leading site affected (50%). Inpatient treatment was required in 93 (27%) patients. CONCLUSIONS. Dog bites in children are frequent and influenced by the breed-related behavior of dogs, dog owners, children, and parents. Therefore, prevention strategies should focus on public education and training of dogs and their owners. Children who are younger than 10 years represent the high-risk group for dog attacks.

Esophagus tissue engineering: in vitro generation of esophageal epithelial cell sheets and viability on scaffold

PURPOSE Management of long gap esophageal atresia poses challenges. The surgical techniques for esophageal replacement are associated with complications and high morbidity. The aim of this study was to develop protocols to obtain single layer sheets of esophageal epithelial cells (EECs) and to investigate their survival on collagen scaffolds. METHODS Esophageal epithelial cells were sourced from adult Sprague-Dawley rats. Briefly, the esophagus was treated with dispase to separate the epithelial layer and further trypsined to obtained EEC. The esophageal epithelial cells were cultured in vitro and seeded on to new generation of 3-dimensional collagen scaffolds. RESULTS Esophageal epithelial cells organized after 48 hours in culture and formed clusters after 72 to 96 hours. Organization of the EEC was completed after 7 days in culture and characteristic sheets of EEC with the histologic morphology of mature esophageal epithelium were obtained after 14 days of culture. Immunohistochemistry demonstrated pure EEC culture using cytokeratin (CK-14) markers. The esophageal epithelial cells transferred on to collagen polymers demonstrated excellent viability after 8 weeks of in vitro culture. CONCLUSION Successful protocols for EEC isolation and proliferation have been established. The engineering of sheets of EEC and the viability of EEC on collagen scaffolds for 8 weeks in vitro, which are prerequisites for esophagus tissue engineering, was demonstrated.

Esophagus tissue engineering: in situ generation of rudimentary tubular vascularized esophageal conduit using the ovine model

PURPOSE Esophagus replacement using the present surgical techniques is associated with significant morbidity. Tissue engineering of the esophagus may provide the solution for esophageal loss. In our attempts to engineer the esophagus, this study aimed to investigate the feasibility of generating vascularized in situ esophageal conduits using the ovine model. METHODS Esophageal biopsies were obtained from lambs, and ovine esophageal epithelial cells (OEEC) were proliferated. The OEEC were seeded on to bovine collagen sheets preseeded with fibroblasts. After 2 weeks of maintaining the constructs in vitro, the constructs were tubularized on stents to create a tube resembling the esophagus and implanted into the omentum for in situ tissue engineering. The edges of the omentum were sutured using nonabsorbable suture material. The implanted constructs were retrieved after 8 and 12 weeks. RESULTS The omental wrap provided vascular growth within and around the constructs as they were integrated along the outer surface area of the scaffold. After removal of the stents, the engineered conduit revealed a structure similar to the esophagus. Histologic investigations demonstrated esophageal epithelium organization into patches on the luminal side and vascular ingrowths on the conduits outer perimeter. CONCLUSION Our study demonstrated the seeding of OEEC on collagen scaffolds and formation of a rudimentary conduit resembling esophageal morphology after in situ omental implantation. Vascular coverage and ingrowth in the periphery of the construct could also be demonstrated. These findings hold future promise for the engineering of the esophagus with improved microarchitecture.

Evaluation of fractures in children and adolescents in a Level I Trauma Center in Austria.

BACKGROUND Injury represents a major concern for children and adolescents worldwide. It is estimated that 10% to 25% of all pediatric injuries will result in fractures. This study aimed to analyze the epidemiology, gender distribution, age, and circumstances of fractures in childhood in a Level I Trauma Center in Austria. METHODS Children managed with fractures between December 2004 and October 2006 were prospectively evaluated. Patients were divided into four age groups: infants (<1 year), preschool children (1-6 years), school-aged children (6-14 years), and adolescents (>14 years). RESULTS The study included 3,339 patients younger than 19 years, who presented with 3,421 fractures. There was a male predominance (61.3%, n = 2,096). Girls (38.7%, n = 1,325) had a lower mean age at presentation of 8.2 years (boys, 9.8 years). An increase in the incidences of fractures was observed until a peak of 11 years in girls and 12 years in boys. A majority of fractures occurred in sports facilities (34.7%), followed by those at home (17.6%) and outdoors (16.7%). The most frequent mechanisms were falls on level surface (41.9%), falls from a height <3 m (23.2%), and involuntary contact with persons or objects (18.2%). The most common fractures were those of the distal radius (15.3%), followed by those of the finger (14%) and distal forearm fractures (8%). CONCLUSION As the Department of Pediatric Surgery in Graz serves as the referral center at least for nearly all major pediatric fractures in the Austrian state of Styria, mechanisms and patterns of major fractures in this study can serve as the basis for state-wide pediatric injury prevention efforts. These prevention strategies should not aim to reduce the level of exposure but should increase the risk awareness and encourage children and their parents to use necessary precautions.

Fluorescence-activated cell sorting of PCK-26 antigen-positive cells enables selection of ovine esophageal epithelial cells with improved viability on scaffolds for esophagus tissue engineering

ObjectiveFor esophagus tissue engineering, isolation and proliferation of esophageal epithelial cells (EEC) is a pre-requisite for scaffold seeding to create constructs. The aim of this study was to sort EEC expressing cytokeratin markers and their proliferative subpopulations; also, to investigate the viability of differentiated EEC subpopulations on collagen scaffolds.MethodsOvine esophageal epithelial cells (OEECs) from sheep esophagus were analyzed using flow cytometry for pan cytokeratin (PCK-26) and proliferation cell nuclear antigen (PCNA). Using fluorescent-activated cell sorting, OEEC were separated and analyzed for PCNA expression. The OEEC subpopulations were seeded on collagen scaffolds for a week in vitro culture.ResultsProliferation cell nuclear antigen was expressed in >45% of OEEC isolated. In flow cytometry, 30% OEEC were PCK-26 positive which exhibited a high-proliferative capacity of 80%. PCK-26-negative OECC exhibited a low-proliferative capability of 13%. Scanning electron microscopy demonstrated organized attachment and uniform scaffold coverage in PCK-26-positive cells.ConclusionOvine esophageal epithelial cells can be divided into PCK-26-positive and negative subpopulations. PCK-26-positive OEEC constitute one-third of the isolated cells with high-proliferative capability. Seeding of PCK-26-positive OEEC on collagen scaffolds leads to uniform distribution of cells in vitro. In esophagus, tissue engineering PCK-26-positive OEEC subpopulation is important for optimal construct generation.

Single-port appendectomy in obese children: an optimal alternative?

Introduction:  The aim of this study was to evaluate our experience with single‐port appendectomy (SPA) in obese children.

Analysis of 347 kindergarten-related injuries

While it has been shown that non-parental childcare is associated with a reduced risk for unintentional injuries, a considerable number of accidents in kindergartens do result in severe injuries. We have collected data on the behavioral and environmental aspects of accidents that occurred in kindergartens in Austria with the aim of determining possible prevention measures. Included in the study were all kindergarten-related injuries (347) from among 21,582 pediatric trauma cases treated in a 22-month period in Graz, Austria. Kindergarten-related injuries that were treated during the same period at six participating hospitals located throughout Austria were used for comparision. A questionnaire was completed at first attendance, and additional information was achieved by interviews with the parents and kindergarten teachers. Only the 347 kindergarten accidents that occurred in Graz were analyzed in detail. Half of the injuries occurred in an outdoor environment (outside), even though most of the time was spent indoors. Boys were more frequently involved in accidents than girls (male:female = 3:2). We identified seasonal and circadian differences, with most children being injured during the first 2 months of attendance (September and October), during the first 3 days of the week (Monday to Wednesday) and in the hour before and after lunch, respectively. Of the 347 accidents analyzed, 24% resulted in serious injury, and injuries occurring outdoors were more severe than those occurring indoors. Most parents felt that the accidents were unpreventable (47%), while 18% stated that improved supervision may have prevented the accident. Kindergarten accidents in Austria still result in a significant number of severe injuries. Kindergarten injuries were related to gender, season, time of day and location. Our results indicate the necessity of a continuous child safety training program that involves the participation of all teachers in day-care functions.

Decellularized ovine esophageal mucosa for esophageal tissue engineering

BACKGROUND The success of a tissue engineered construct is greatly influenced by the choice of scaffold material. Decellularized esophageal matrix is a promising material for esophageal tissue engineering. The aim of this study was to develop a decellularized ovine esophageal mucosa and to investigate the effect of decellularization on the appearance of the resulting tissue. METHODS Ovine esophagi were decellularized by combination of agitation, enzymatic digestion and treatment with 1 and 5% sodium dodecyl sulphate (SDS). Efficiency of decellularization was assessed by histological examination and DNA quantification. Finally, the effect of decellularization on tissue morphology was investigated by scanning electron microscopy. RESULTS Decellularization resulted in a highly efficient removal of cells and DNA content. Electron microscopic investigation revealed a denuded, rough, undulating surface with preserved papillary structures. Individual papillae had a length of approximately 55 μm and were present at a density of 1332 μm/mm(2). Closer examination revealed a tightly packed sponge-like appearance with pores in the region of 300 nm. Numerous, intact collagen fibres were also visible. CONCLUSION Ovine esophagus can be successfully decellularized through treatment with SDS. The resulting decellularized mucosal surface possesses a rough, 2D surface with a well preserved extracellular matrix. Such a material may be of advantage in tissue engineering of the esophagus. Characterisation of the papillary layer gives important insight into the suitability of decellularized esophageal mucosa for use in esophageal reconstruction and also provides morphological information which may help in the design of synthetic, biomimetic materials.

Effects of sodium hydroxide exposure on esophageal epithelial cells in an in vitro ovine model: implications for esophagus tissue engineering

BACKGROUND Esophagus tissue engineering holds promises for esophageal replacement after severe caustic injuries. The aim of this study was to determine whether viable esophageal epithelial cells could be isolated from an esophagus exposed to varying concentrations of alkali with regard to number, viability, and morphology during in vitro culture. METHODS Ovine esophagi were exposed to phosphate-buffered saline 2.5%, 15%, or 25% sodium hydroxide (NaOH). The effect of NaOH concentrations on epithelial damage was assessed histologically. Esophageal epithelial cells were then isolated, and cell count and viability were investigated. Finally, cell number, viability, and morphology of esophageal epithelial cells were determined for 24 days of in vitro culture. RESULTS Histologic analysis showed a progressive destruction of the epithelium proportional to increasing NaOH concentrations. Esophagi treated with phosphate-buffered saline and 2.5% NaOH showed significantly higher viable cell counts after isolation and culture in comparison with those treated with 15% to 5% NaOH. CONCLUSION The evidence presented in this study indicates that epithelial biopsies from an esophagus exposed to low concentrations (2.5%) of NaOH will still yield large numbers of viable cells suitable for tissue engineering applications. In cases of exposure to higher concentrations (15%-25%), alternative cell sources for epithelial regeneration, such as stem cells, will be necessary for tissue engineering applications.

Esophageal smooth muscle cells dedifferentiate with loss of α-smooth muscle actin expression after 8 weeks of explant expansion in vitro culture: Implications on esophagus tissue engineering

SummaryBACKGROUND: Esophagus tissue engineering using the hybrid-construct approach involves assembly of the esophageal components to engineer the organ. This study investigated the dedifferentiation and loss in expression of esophageal smooth muscle after explant expansion in culture. METHODS: Ovine esophagus smooth muscle cells (OESMC) were sourced from adult biopsies and expanded using the explant culture technique. The explants were maintained under static in vitro tissue culture. Flow cytometry analysis was performed for α-smooth muscle actin (α-SMA) expression at intervals of 4 weeks for up to 8 weeks. RESULTS: After 4 weeks 58.5% OESMC exhibited α-SMA which decreased to 28.5% after 6 weeks in culture. After 8 weeks in culture a mere 1.3% OESMC demonstrated α-SMA expression. CONCLUSIONS: OESMC proliferated using the explant technique exhibit a total loss of α-SMA expression after 8 weeks of static in vitro culture. This information is crucial for tissue engineering of the esophagus using the hybrid-construct approach.