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Biomedical subjects

Florian Gebhard

Publications and source records attributed to Florian Gebhard.

25 records · Page 2Linked to original sources
PubMed2003

Cardiopulmonary, histological, and inflammatory alterations after lung contusion in a novel mouse model of blunt chest trauma.

Severe blunt chest trauma remains an important injury with high morbidity and mortality. However, the associated immunological alterations are poorly understood. Existing big animal models require large-scale settings, are often too expensive, and research products for immunological studies are limited. In this study we aimed to establish a new model of blunt, isolated and bilateral chest trauma in mice and to characterize its effects on physiological and inflammatory variables. Male C3H/HeN mice (n = 9-10/group) were anesthetized and a femoral artery was catheterized. The animals were subjected to trauma or sham procedure and monitored for 180 min. Blunt chest trauma was induced by a blast wave focused on the thorax. Trauma intensity was optimized by varying the exposure distance. Blood pressure, heart rate, respiratory rate, arterial blood gases and plasma cytokine levels were measured. Macroscopic and microscopic examinations were performed. In addition, outcome was evaluated in a 10-day survival study. Chest trauma caused a drop (P < 0.05) in blood pressure and heart rate, which partly recovered. Blood gases revealed hypoxemia and hypercarbia (P < 0.05) 180 min after trauma. There was marked damage to the lungs but none to abdominal organs. Histologically, the characteristic signs of a bilateral lung contusion with alveolar and intrabronchial hemorrhage were found. Plasma interleukin-6 and tumor necrosis factor alpha were considerably increased after 180 min. Blunt chest trauma resulted in an early mortality of 10% without subsequent death. On the basis of these findings, this novel mouse model of blunt chest trauma appears suitable for detailed studies on immunological effects of lung contusion.

Animals↗
PubMed2003

Induction of apoptosis following blunt chest trauma.

The cause for the high morbidity of blunt chest trauma is not fully understood. It is still unclear if and to what extent a second insult, e.g., apoptotic tissue damage initiated by the primary insult itself, may contribute to the development of serious complications. This study was done to elucidate whether a pulmonary contusion may induce programmed cell death. Sixty-four Wistar rats were evenly randomized to eight experimental groups: four sets were subjected to a standardized blast wave injury and sacrificed 6, 24, 48, and 72 h after the trauma; four groups served as controls for the same time points. Lung and liver samples were stained (H & E; TUNEL), and PMN infiltration was determined by myeloperoxidase (MPO) activity. Caspase 8 was analyzed by Western blot, and TNF-alpha plasma levels by ELISA. Postmortem examination revealed bilateral pulmonary contusion in trauma animals with higher (P < 0.05) numbers of apoptotic cells in lung but not in liver tissue as early as 6 h after the injury. This amount gradually increased and reached a maximum after 48 h: 6.8 +/- 1.1 apoptotic cells/hpf vs. 0.6 +/- 0.06 in controls. Chest trauma caused an increased expression of active caspase 8 in lung but not in liver tissue at 48 and 72 h. TNF-alpha plasma levels were not different. MPO activity in lung tissue of trauma animals increased (P < 0.05) after 6 h and peaked at 72 h. This study has provided the first evidence that apoptotic cell death in lung tissue is initiated following (experimental) pulmonary contusion. The exact mechanism remains, however, unclear and has to be elucidated further.

Animals↗
PubMed2002

Spinal navigation in tumor surgery of the thoracic spine: first clinical results.

In this clinical study, the accuracy of computed tomography-based and computer-guided decompression and insertion of pedicle screws in patients who have had tumor-related posterior surgery of the thoracic spine was evaluated. Eight patients with advanced metastatic disease were treated surgically using a posterior approach with the assistance of an optoelectronic navigation system. Postoperative computed tomography scans were obtained for all patients and provided information regarding decompression and transpedicle implant localization. In all eight patients accurate decompression of the spinal canal was seen. Using the navigation system, 22 of 26 scheduled transpedicle screws were inserted using computer guidance. Eighty-six percent (19 of 22) of the navigated pedicle screws were positioned centrally in the bone. Initial results indicate that computer-aided frameless navigation in tumor surgery of the thoracic spine is a safe system to improve surgical performance during posterior decompression and transpedicle stabilization. Although computed tomography-based computer-assisted spinal navigation is important, the system is not 100% accurate. Therefore, application of the navigation system should be restricted to experienced surgeons who can continue the operation using a conventional approach. Finally, detailed knowledge of the principles of the tracking systems is necessary to prevent possible misinterpretation of information provided by the computer.

Bone Screws↗
PubMed2002

Chemokine activation within 24 hours after blunt accident trauma.

Chemokines mediate the migration of leukocytes to sites of inflammation. Changes in the plasma concentration of interleukin (IL)-8 and macrophage inflammatory protein (MIP)-1beta have not been investigated in the very early phase starting immediately after unintentional trauma. Enrolled in the study were 94 patients with multiple blunt injuries. Blood samples were collected at the scene of accident, then at regular intervals for 24 h. IL-8 and MIP-1beta plasma levels were determined by commercial test kits. Patients were grouped according to trauma severity, pattern of injury, as well as survivors vs. nonsurvivors. Serious casualties [Injury Severity Score (ISS) > or = 32] revealed a significant increase in IL-8 compared to only a slight elevation in individuals with an ISS < 32. Nonsurvivors showed a highly significant (P < 0.005) increase in IL-8 levels beginning immediately after admission. Trauma resulted in a modest activation of MIP-1beta production without differences regarding trauma severity, pattern of injury, or survival. A very strong trauma stimulus is necessary to activate IL-8 production. In contrast to MIP-1beta, IL-8 levels were significantly elevated in nonsurvivors compared to survivors. Therefore, IL-8 might be an early predictor of survival.

Accidents↗
PubMed2002

Pancreatic injury in severe trauma: early diagnosis and therapy improve the outcome.

BACKGROUND: Pancreatic injury is a dangerous complication in multiple injury, and experience with its diagnosis and treatment is usually limited. METHOD: Retrospective analysis of 3,840 patients admitted after multiple trauma from January 1, 1982, until May 31, 2000. RESULTS: A laparotomy was performed in 121 cases (3.15%) due to suspected intra-abdominal lesion. 32% of the patients (39/121) had a pancreatic lesion; 23% (9/39) had a rupture of the major pancreatic duct. Primary laparotomy was performed in 72% of the patients (28/39). Superficial lesions were treated by explorative laparotomy alone (n = 7), debridement and external drainage (n = 20), or necrosectomy and lavage (n = 3). Complex pancreatic lesions were treated by pancreatojejunostomies (n = 5), pancreatic left resections (n = 2), or exploration alone (n = 2). 8 of 39 patients died (20%), 4 intraoperatively. Of the surviving 35 patients, a pancreas-associated complication developed in 8 patients (23%): pancreatic abscesses (n = 4), traumatic pancreatitis (n = 3), pancreatic fistulas (n = 2), and pseudocysts (n = 2). CONCLUSIONS: Pancreatic injury is an infrequent but dangerous complication in severe trauma. Superficial lesions not affecting the major pancreatic duct can be managed by debridement and external drainage. If the major pancreatic duct is ruptured, organ-preserving, complex reconstructive procedures are necessary. When diagnosed timely and treated according to severity and overall situation, pancreatic injuries have an acceptable morbidity, but usually a high mortality.

Abdominal Injuries↗
PubMed2002

Ultrasound, a new tool for surface matching in computer-navigated surgery.

OBJECTIVE: The object of this study was to investigate the feasibility of generating a bone surface from data provided by an ultrasound examination and to match this surface with the previous computed tomography (CT) scan. METHODS: From a CT data set of a training model of the pelvis, a three-dimensional surface was extracted by global thresholding-based segmentation. The same model was placed in a water basin, and ultrasound images were taken with a guided ultrasound transducer. The three-dimensional surface was generated from the ultrasound data set, and the two surfaces were matched in a semiautomatic mode. RESULTS: With special segmentation methods, a surface could be extracted automatically from the CT and the ultrasound data set. From these segmented ultrasound slices, a volume data set of the model was generated. After approximate initial matching, the local matching process was completed automatically. CONCLUSION: One of the limitations in computer-assisted surgery is the complicated matching process. Using special algorithms, a surface was extracted from the data set of an ultrasound examination and matched in a semiautomatic mode with the surface of a CT data set, facilitating the matching process.

Algorithms↗