In vivo measurement of bending stiffness in fracture healing

BACKGROUND: Measurement of the bending stiffness a healing fracture represents a valid variable in the assessment of fracture healing. However, currently available methods typically have high measurement errors, even for mild pin loosening. Furthermore, these methods cannot provide actual values of bending stiffness, which precludes comparisons among individual fractures. Thus, even today, little information is available with regards to the fracture healing pattern with respect to actual values of bending stiffness. Our goals were, therefore: to develop a measurement device that would allow accurate and sensitive measurement of bending stiffness, even in the presence of mild pin loosening; to describe the course of healing in individual fractures; and help to evaluate whether the individual pattern of bending stiffness can be predicted at an early stage of healing. METHODS: A new measurement device has been developed to precisely measure the bending stiffness of the healing fracture by simulating four-point-bending. The system was calibrated on aluminum models and intact tibiae. The influence of pin loosening on measurement error was evaluated. The system was tested at weekly intervals in an animal experiment to determine the actual bending stiffness of the fracture. Transverse fractures were created in the right tibia of twelve sheep, and then stabilized with an external fixator. At ten weeks, bending stiffness of the tibiae were determined in a four-point-bending test device to validate the in-vivo-measurement data. RESULTS: In-vivo bending stiffness can be measured accurately and sensitive, even in the early phase of callus healing. Up to a bending stiffness of 10 Nm/degree, measurement error was below 3.4% for one pin loose, and below 29.3% for four pins loose, respectively. Measurement of stiffness data over time revealed a significant logarithmic increase between the third and seventh weeks, whereby the logarithmic rate of change among sheep was similar, but started from different levels. Comparative measurements showed that early individual changes between the third and fourth weeks can be used as a predictor of bending stiffness at seven weeks (r = 0.928) and at ten weeks (r = 0.710). CONCLUSION: Bending stiffness can be measured precisely, with less error in the case of pin loosening. Prediction of the future healing course of the individual fracture can be assessed by changes from the third to the fourth week, with differences in stiffness levels. Therefore, the initial status of the fracture seems to have a high impact on the individual healing course

Aktuelle Möglichkeiten und Herausforderungen bei der Diagnostik des laryngopharyngealen Refluxes

Der laryngopharyngeale Reflux (LPR) ist definiert als ein Zurückfließen von gastralem bzw. gastroduodenalem Sekret in den Larynx- bzw. Pharynxbereich und ist durch ein sehr breites Spektrum an teils unspezifischen Symptomen wie beispielsweise chronischem Husten, zervikalem Globusgefühl oder Hypersekretion von Mukus im Larynx und Pharynx charakterisiert. Aufgrund des Fehlens eines Goldstandards und der heterogenen Studienlage gestaltet sich die Diagnosestellung des LPR jedoch weiterhin schwierig und wird in absehbarer Zeit weiterhin kontrovers diskutiert werden. Insgesamt kann man jedoch davon ausgehen, dass bei suggestiver Anamnese mit erhöhten Scores im Reflux Symptom Index (RSI), entsprechenden endoskopischen Befunden mit pathologischem Reflux Finding Score (RFS) und auffälliger ösophagealer oder oropharyngealer 24-h-pH-Metrie ohne Hinweise auf eine andere Grunderkrankung die Diagnose eines LRP wahrscheinlich ist. In der vorliegenden Übersichtsarbeit sollen die genannten Methoden ebenso wie neuere Werkzeuge bei der Diagnose des LPR kritisch diskutiert werden

The Role of Emotional Contagion in the Distress Exhibited by Grouped Mice Exposed to CO₂.

The 2013 AVMA Guidelines for the Euthanasia of Animals recommends a chamber volume displacement rate of 10% to 30% per minute (v/min) when euthanizing small laboratory rodents with CO₂. Group euthanasia of mice is a common practice, and grouping strangers is often avoided to minimize distress; however, emotional contagion, which occurs between familiar animals but not strangers, has not been studied in the context of group CO₂ euthanasia. This study examined cagemate- and stranger-grouped mice exposed to 10%, 30%, or 50% v/min CO₂ to determine whether emotional contagion plays a role in this context and whether that role is influenced by CO₂ flow rate. Videos of adult male C57BL/6J mice exposed to different CO₂ flow rates were scored for durations of dyspnea, ataxia, and consciousness as well as the numbers of face pawing and jump behaviors. Blood was collected at time of unconsciousness and assayed for ACTH. Cagemates experienced significantly longer durations of conscious dyspnea and ataxia with 10% v/min CO₂ compared with 30% and 50% v/min. Similarly, strangers experienced significantly longer duration of conscious dyspnea with 10% v/min CO₂ compared with 30% and 50% v/min and significantly longer duration of ataxia with 10% compared with 50% v/min. Cagemates showed significantly more jumps with 10% v/min CO₂ compared with 30% and 50% v/min, whereas jumping was unaffected by CO₂ flow rate in strangers. We conclude that more potential for distress exists when cagemate and stranger mice are exposed to a 10% v/min CO₂ flow rate and that emotional contagion may contribute to distress in cagemates at this flow rate. Therefore, we propose that 30% v/min CO₂ should be used for euthanasia of mice, and that 50% v/min should also be considered humane

Seismische Verhaeltnisse und seismische Ueberwachung des Salzbergwerkes Asse

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman