Timing of osteosynthesis of fractures in children changes the outcome.

PURPOSE: The search for optimal treatment strategies for fractures in children that require osteosynthesis is controversial and is still being debated. A major factor that has been under discussion is the impact of the timing of surgery: the time delay between the trauma and the operation, as well as the duration of the surgical procedure, and the time of day that the operation is performed are potential factors that might influence the outcome. Therefore, the aim of our study was to investigate the influence of these factors on the outcome after osteosynthesis of diverse fractures of the extremities in children. METHODS: In a retrospective study, 387 patients aged 1-18 years who presented with fractures of the extremities that underwent surgery were included. Patient records including radiological studies were analyzed. The follow up period lasted at least 12 months or until recovery. Statistical significance was set at an alpha level of P ≤ 0.05. RESULTS: Delayed surgery, as well as a prolonged duration of surgery, and the mode of transportation of the patient significantly were related to a higher rate of complications. However, in this study, the complication rate was not found to be influenced by the mode of reduction of the fracture, or the time of day or the day of the week. A further parameter that significantly changed the outcome was the mechanism of injury. However, the rate of complications was unchanged if a resident or a consulting was the performing surgeon so that a resident can safely perform the procedure in the presence of a consultant. CONCLUSION: Timing of surgery for fractures of the extremities in children, including the time from trauma to surgery, the duration of the operation and the mode of transportation to the ER, were found to have a significant impact on the occurrence of complications in this study while the mode of reduction and the time of day did not change the outcome. Future studies with a focus on selected types of fractures are needed to further enlighten this topic. LEVEL OF EVIDENCE: Retrospective comparative study, level III.

Metabolic profiling of glycerophospholipid synthesis in fibroblasts loaded with free cholesterol and modified low density lipoproteins.

Currently, the detailed regulation of major pathways of glycerophospholipid synthesis upon cholesterol loading is largely unknown. Therefore, a detailed lipid metabolic profiling using stable isotope-labeled choline, ethanolamine, and serine was performed by quantitative electrospray ionization tandem mass spectrometry (ESI-MS/MS) in free cholesterol (FC), oxidized (Ox-LDL) and enzymatically modified LDL (E-LDL)-loaded primary human skin fibroblasts. As previously described, an adaptive induction of phosphatidylcholine (PC) synthesis via CDP-choline was found upon FC loading. In contrast to PC, CDP-ethanolamine-mediated phosphatidylethanolamine (PE) synthesis was inhibited by FC incubation. Furthermore, FC induced a shift toward polyunsaturated PE and PC species, which was mediated primarily by PE biosynthesis but not PE remodeling, whereas PC species were shifted mainly by fatty acid (FA) remodeling of existing PC. Modified lipoprotein incubation revealed rather different effects on glycerophospholipid synthesis. E-LDL greatly enhanced PC synthesis, whereas Ox-LDL did not change PC synthesis. Addition of different free FAs (FFA) with and without FC coincubation, as major components of E-LDL, clearly indicated an incorporation of FFA into newly synthesized PC and PE species as well as FFA as important driving force for PC synthesis. Because FC and FFA are known to affect lipid membrane properties including membrane curvature, these data support that CTP:phosphocholine cytidylyl-transferase activity and consequently PC synthesis are regulated by modulation of membrane characteristics at the cellular level. In conclusion, the application of high throughput metabolic profiling of major glycerophospholipid pathways by ESI-MS/MS is a powerful tool to unravel mechanisms underlying the regulation of cellular lipid metabolism.

High throughput quantification of cholesterol and cholesteryl ester by electrospray ionization tandem mass spectrometry (ESI-MS/MS).

Analysis of free cholesterol (FC) is not well suited for electrospray ionization (ESI); however, cholesteryl ester (CE) form ammonium adducts in positive ion mode and generate a fragment ion of m/z 369 upon collision-induced fragmentation. In order to allow parallel analysis of FC and CE using ESI tandem mass spectrometry (ESI-MS/MS), we developed an acetyl chloride derivatization method to convert FC to cholesteryl acetate (CE 2:0). Derivatization conditions were chosen to provide a quantitative conversion of FC to CE 2:0 without transesterification of naturally occurring CE species. FC and CE were analyzed by direct flow injection analysis using a fragment of m/z 369 in a combination of selected reaction monitoring (SRM) and precursor ion scan for FC and CE, respectively. Quantification was achieved using deuterated D(7)-FC and CE 17:0/CE 22:0 as internal standards as well as calibration lines generated by addition of FC and naturally occurring CE species to the respective sample matrix. The developed assay showed a precision and detection limit sufficient for routine analysis. A run time of 1.3 min and automated data analysis allow high throughput analysis. Loading of human skin fibroblast and monocyte derived macrophages with stable isotope labeled FC showed a potential application of this method in metabolism studies. Together with existing mass spectrometry methodologies for lipid analysis, the present methodology will provide a useful tool for clinical and biochemical studies and expands the lipid spectrum that can be analyzed from one lipid sample on a single instrumental platform.