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Biomedical subjects

C Burger

Publications and source records attributed to C Burger.

At least 19 recordsLinked to original sources
PubMed2007

[Elastic titanium nails in minimally invasive osteosynthesis for mid-clavicular fractures].

BACKGROUND: In up to 31% of cases, conservative treatment of mid-clavicular fractures leads to unsatisfactory results. The aim of this study was to define the value of minimally invasive elastic stable intramedullary nailing (ESIN) of mid-clavicular fractures with titanium elastic nails. MATERIAL AND METHODS: Within 5 years, ESIN was performed in 45 patients. We studied the functional results and complications. RESULTS: Retrospectively we analysed the results of all patients at a mean follow-up of 24.7+/-2.4 months. Iatrogenic perforation of the lateral cortex occurred twice and medial migration in eight patients. Superficial skin infection developed in one. Nail breakage after fracture healing was observed twice. Twelve patients sustained clavicular shortening of > or =5 mm in relation to the intact contralateral side. After 6 months the mean constant score was 94.3+/-2 points, and the mean DASH score was 5.4+/-2.2 points. CONCLUSION: Intramedullary stabilisation of mid-clavicular fractures with titanium elastic nails is a minimally invasive technique with good functional results. Patients must be informed about the possibility of open reduction in about half of the cases as well as shoulder asymmetry, migration of the nail, and iatrogenic nerve and vessel injury.

Adult↗
PubMed2006

Retropatellar chondromalacia associated with medial osteoarthritis after meniscus injury. One year of observations in sheep.

BACKGROUND/AIMS: In an ovine meniscal repair model, the patellofemoral (PF) osteoarthritis due to a non-sutured tear or failed repair was investigated. METHODS: A radial meniscus tear was either sutured with polydioxanone (PDS), with a slow degrading polylactide long-term suture(LTS) or left without treatment. Knee joint cartilage in the PF and medial compartment was evaluated compared to normal knees (healthy controls). RESULTS: Retropatellar osteoarthritis in the non-sutured and sutured animals was intense in contrast to the control knees after 6 months in all groups (p < 0.001), and after 12 months in the PDS group (p < 0.001), LTS group and non-sutured animals (p < 0.05). CONCLUSION: Non-sutured meniscus tears and failed repair lead fast to intense PF osteoarthritis corresponding with tibial damage of the injured compartment.

Animals↗
PubMed2006

[Trauma mechanism and diagnosis of blunt diaphragmatic rupture].

BACKGROUND: Indirect diaphragmatic rupture (DR) is defined as acquired complete split of the diaphragm after blunt trauma and occurs in 1-5% of massively traumatized patients. The diagnosis is often difficult. However, particular trauma mechanisms and associated injuries may suggest the existence of DR. METHODS: A retrospective study was done of 21 consecutive patients from 1993 to 2004 at an university hospital. RESULTS: This study revealed a striking combination of DR with pelvic fractures (12/21, 57%). Of 19 polytraumatized patients, diagnosis was made initially in 13 (68%) and with a delay in six (32%). Right-sided injuries were common (8/21, 38%). Thus a 'protective' function of the liver does not exist. Diaphragmatic rupture can be missed in ventilated patients until extubation leads to herniation of abdominal organs into the thorax. CONCLUSIONS: Diaphragmatic rupture should be excluded in all severely abdominally traumatized patients, in particular those with concomitant pelvic fracture. Computed tomography with oral contrast medium is diagnostic in most cases. Access by laparotomy should be preferred after acute trauma, since additional intra-abdominal injuries are frequent.

Accidental Falls↗
PubMed2006

[Helical computed tomography in penetrating injury to the torso. Diagnostic value in emergent use].

BACKGROUND: Nontherapeutic laparotomy and thoracotomy rates in penetrating torso trauma remain high. The aim of this study was to define the value of helical computed tomography (CT) in this emergency situation. MATERIAL AND METHODS: Retrospectively, we studied 11 hemodynamically stable patients with penetrating injury to the torso admitted to our trauma center over a 3-year period who underwent intravenous contrasted helical CT immediately after admission. A positive CT scan was defined as showing any evidence of intrathoracal or intra-abdominal injury necessitating immediate operation. Patients with positive CT underwent laparotomy and/or thoracotomy. Patients with negative CT were observed. RESULTS: Eleven consecutive patients were studied: nine male, two female; mean age 39 years (range 19-62). Nine stab wounds and two shotgun wounds were seen. Seven patients had positive helical CT findings, and four patients were negative. All patients with positive CT findings were operated on; those with negative scans recovered uneventfully. This imaging method accurately predicted whether thoracotomy or laparotomy was needed in 10/11 cases. CONCLUSION: In penetrating torso trauma, helical CT can clarify the need for thoracotomy or laparotomy vs nonoperative treatment.

Abdominal Injuries↗
PubMed2006

[Acute colonic pseudoobstruction following fixation of a pertrochanteric fracture].

Acute colonic pseudoobstruction, following traumatic injuries, is a rare diagnosis. Nevertheless it is life threatening, if it is not recognized and treated promptly. We report one case of this so-called Ogilvie's syndrome, which followed fixation of a trochanteric fracture by intramedullary nailing within 2 days. Due to massive acute colonic distension, the patient suffered from respiratory failure. We excluded other intestinal diseases by CT scanning. After conservative colonic decompression, he recovered after 2 days in the intensive care unit. We describe a variable treatment depending on the severity of the colonic atony. Knowledge of Ogilvie's syndrome, or acute colonic pseudoobstruction, is a must for trauma surgeons, since it can occur within a few hours and can lead to dramatic situations.

Acute Disease↗
PubMed2006

[Bipolar dislocation injury of the forearm].

Bipolar dislocation injury of the forearm is rarely documented. It is a combined forearm injury with trauma on the elbow side and on the side of the wrist joint. We describe two different cases of this complex dislocation. The first patient suffered from a Monteggia-like dislocation fracture with transscaphoid dislocation of the wrist. The second person had an acute longitudinal radioulnar membrane dissociation after elbow dislocation with an additional scapholunate tendon rupture. The difficult management of these injuries is illustrated by these cases.

Elbow Joint↗
PubMed2004

Thermally induced phase transitions and morphological changes in organoclays.

Thermal transitions and morphological changes in Cloisite organoclays were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and in situ simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) over the temperature range of 30-260 degrees C. On the basis of DSC and FTIR results, the surfactant component in organoclays was found to undergo a melting-like order-disorder transition between 35 and 50 degrees C. The transition temperatures of the DSC peaks (Ttr) in the organoclays varied slightly with the surfactant content; however, they were significantly lower than the melting temperature of the free surfactant (dimethyldihydrotallowammonium chloride; Tm = 70 degrees C). FTIR results indicated that within the vicinity of Ttr, the gauche content increased significantly in the conformation of surfactant molecules, while WAXD results did not show any change in three-dimensional ordering. Multiple scattering peaks were observed in SAXS profiles. In the SAXS data acquired below Ttr, the second scattering peak was found to occur at an angle lower than twice that of the first peak position (i.e., nonequidistant scattering maxima). In the data acquired above Ttr, the second peak was found to shift toward the equidistant position (the most drastic shift was seen in the system with the highest surfactant content). Using a novel SAXS modeling technique, we suggest that the appearance of nonequidistant SAXS maxima could result from a bimodal layer thickness distribution of the organic layers in organoclays. The occurrence of the equidistant scattering profile above Ttr could be explained by the conversion of the bimodal distribution to the unimodal distribution, indicating a redistribution of the surfactant that is nonbounded to the clay surface. At temperatures above 190 degrees C, the scattering maxima gradually broadened and became nonequidistant again but having the second peak shifted toward a scattering angle higher than twice the first peak position. The changes in SAXS patterns above 190 degrees C could be attributed to the collapse of organic layers due to desorption and/or degradation of surfactant component, which was supported by the TGA data.

Journal Article↗
PubMed2004

[Spondylodiscitis after perioperative peridural catheter].

Peridural anaesthesia is used to avoid operative, postoperative and chronic pain, especially in surgery, gynecology and urology. Complications have rarely been described but can entail serious local and systemic sequelae. Three cases with spondylitis and spondylodiscitis after peridural anaesthesia are presented. The failure to recognize the peridural catheter as the cause of vertebral pain led to therapeutic delay in two cases. The result of antimicrobial therapy and in two cases radical surgical treatment was complete recovery. The occurrence of spondylodiscitis after the use of peridural catheters is often a late manifestation of disseminated pathogens. The insidious progression of infection and non-specificity of clinical symptoms may lead to diagnostic delay. Awareness of the possibility of even delayed complications after the use of peridural anaesthesia is important.

Adult↗
PubMed2004

[Benign desmoplastic fibroblastoma of the lower leg. A rare case].

Desmoplastic fibroblastoma ("collagenous fibroma") is a benign fibrous soft tissue tumor. We report a rare case of a "collagenous fibroma" located in the proximal lower leg in 56-year-old man. The clinical, radiological, and pathological-morphological findings are documented. The operative treatment was performed according to general principles of surgical management of benign soft tissue tumors.

Fibroma, Desmoplastic↗
PubMed2004

Synergistic value of fibrinolysis and hypothermic aerobic preservation with oxygen in the protection of livers from non-heart-beating donors: an experimental model.

The chronic organ shortage has led to the reconsideration of marginal donor pools such as non-heart-beating donors (NHBD). The use of these livers is limited due to their minimal tolerance for cold preservation. The aim of this study was to examine the combination of two different therapeutic strategies for the preservation of livers from NHBD. The livers of male Wistar rats were harvested after the induction of cardiac arrest via phrenotomy (30, 90 minutes). Livers were perfused with 10 mL of UW solution (UW), followed by hypothermic preservation with or without insufflation of gaseous oxygen (O2). In one group a fibrinolytic preflush (10 mL of Ringer's containing 7500 IU of streptokinase) was performed with subsequent preservation with O2 (O2+SK). After storage (24 h/4 degrees C/UW) livers were reperfused in vitro. Livers retrieved from heart beating donors served as controls. The results showed that even after only 30 minutes of warm ischemia livers displayed a serious disturbance in vascular perfusion (portal venous pressure, PVP = 7.4 +/- 0.2* versus control: 4.1 +/- 0.5 mmHg), associated with a more than 10-fold increase in enzyme release (ALT: 26819 +/- 513* versus control 683 +/- 152 mU/g/L), which was consistent with a significant depression in bile synthesis (1.21 +/- 0.35* versus 19.36 +/- 2.16 microL/g/45 min). However, these impairments could be prevented with O2. Even after 90 minutes of WI, the function was significant better using aerobic preservation (ALT: 3204 +/- 549 mU/g/L). With a supplementary fibrinolytic preflush, we effectively preserved livers up to 90 minutes of WI with results comparable to livers from heart beating donors with no WI (ALT: 1623 +/- 432 mU/g/L). The combination of these two techniques represents a new therapeutic approach for livers with extended or unclear WI periods in non-heart-beating donors (*P <.05 versus control).

Adenosine↗
PubMed2004

Optical imaging of the spatiotemporal dynamics of cerebral blood flow and oxidative metabolism in the rat barrel cortex.

Oxidative metabolism and cerebral blood flow (CBF) are two of the most important measures in neuroimaging. However, results from concurrent imaging of the two with high spatial and temporal resolution have never been published. We used flavoprotein autofluorescence (AF) and laser speckle imaging (LSI) in the anaesthetized rat to map oxidative metabolism and CBF in response to single vibrissa stimulation. Autofluorescence responses reflecting oxidative metabolism demonstrated a fast increase with a delay of 0.1 s. The sign-reversed speckle contrast reflecting CBF started to rise with a delay of 0.6 s and reached its maximum 1.4 s after the stimulation offset. The fractional signal changes were 2.0% in AF and 9.7% in LSI. Pixelwise modelling revealed that CBF maps spread over an area up to 2.5-times larger than metabolic maps. The results provide evidence that the increase in cerebral oxidative metabolism in response to sensory stimulation is considerably faster and more localized than the CBF response. This suggests that future developments in functional imaging concentrating on the metabolic response promise an increased spatial resolution.

Animals↗
PubMed2002

Process development of a recombinant antibody/interleukin-2 fusion protein expressed in protein-free medium by BHK cells.

The production, purification and stability of quality (in terms of integrity and glycosylation) of an antibody/interleukin-2 fusion protein with potential application in tumour-targeted therapy expressed in BHK21 cells are described. Consistency of the product throughout time was determined by analysis of glycosylation of the fusion protein using MALDI-TOF mass spectroscopy and HPAEC-PAD combined with product integrity studies by SDS-PAGE and Western blotting. These investigations showed consistent expression in terms of integrity and of three major oligosaccharide structures of the fusion protein after 62 generations. The data obtained at this stage indicated the suitability of the cell line for production purposes. Different approaches for the production of this protein were subsequently carried out. The relative productivity of the recombinant fusion protein and general performance of the cells in two different protein-free medium (PFM) culture systems, continuous chemostat and continuous perfusion using a Centritech centrifuge as a cell retention device, were studied. The results indicate that the chemostat culture resulted in more stable and controllable nutrient environment, which could indicate better product consistency, in accordance with what has been observed under serum-containing conditions, in relation to the perfusion culture. Finally, product obtained from the chemostat culture was analysed and purified. The purification process was optimised with an increase in the overall yield from 38 to 70% being obtained, a significant improvement with important consequences for the implementation of an industrial-scale culture system. In conclusion, it was possible to produce and purify the recombinant antibody/interleukin-2 fusion protein assuring the quality and stability of the product in terms of integrity and glycosylation. Therefore, a candidate production process was established.

Animals↗
PubMed2002

PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients.

The CT data acquired in combined PET/CT studies provide a fast and essentially noiseless source for the correction of photon attenuation in PET emission data. To this end, the CT values relating to attenuation of photons in the range of 40-140 keV must be transformed into linear attenuation coefficients at the PET energy of 511 keV. As attenuation depends on photon energy and the absorbing material, an accurate theoretical relation cannot be devised. The transformation implemented in the Discovery LS PET/CT scanner (GE Medical Systems, Milwaukee, Wis.) uses a bilinear function based on the attenuation of water and cortical bone at the CT and PET energies. The purpose of this study was to compare this transformation with experimental CT values and corresponding PET attenuation coefficients. In 14 patients, quantitative PET attenuation maps were calculated from germanium-68 transmission scans, and resolution-matched CT images were generated. A total of 114 volumes of interest were defined and the average PET attenuation coefficients and CT values measured. From the CT values the predicted PET attenuation coefficients were calculated using the bilinear transformation. When the transformation was based on the narrow-beam attenuation coefficient of water at 511 keV (0.096 cm(-1)), the predicted attenuation coefficients were higher in soft tissue than the measured values. This bias was reduced by replacing 0.096 cm(-1) in the transformation by the linear attenuation coefficient of 0.093 cm(-1) obtained from germanium-68 transmission scans. An analysis of the corrected emission activities shows that the resulting transformation is essentially equivalent to the transmission-based attenuation correction for human tissue. For non-human material, however, it may assign inaccurate attenuation coefficients which will also affect the correction in neighbouring tissue.

Calibration↗
PubMed2002

White matter glucose metabolism during intracortical electrostimulation: a quantitative [(18)F]Fluorodeoxyglucose autoradiography study in the rat.

[(18)F]Fluorodeoxyglucose (FDG) autoradiography was used to analyze the effects of intracortical electrostimulation on local cerebral metabolic rate for glucose (LCMRglu). The hindleg area in rat brains was electrically stimulated with different frequencies (0, 0.1, 0.25, 0.5, 0.75, 1 stimulus trains per second, two animals per condition). The major result was a strong positive correlation between stimulation frequency and LCMRglu in the callosal fibers originating in the stimulated cortical area. At the highest stimulation frequency callosal LCMRglu was 50.01 micromol/min/100 g compared to 27.87 micromol/min/100 g at baseline. LCMRglu in gray and white matter control areas was stable across conditions. Direct injection of FDG in the stimulated cortex failed to produce increased callosal uptake, excluding the possibility that FDG uptake in the corpus callosum is related to axonal diffusion. Although several previous autoradiographic studies have demonstrated alterations in LCMRglu in white matter, correlations between neural activity and LCMRglu have never been explicitly addressed. Changes in white matter metabolism most likely reflect changes of electrical fiber activity and thus the presented results bear important implications for brain imaging studies.

Animals↗
PubMed2002

PET studies of 18F-memantine in healthy volunteers.

Previous studies in mice and PET investigations in a Rhesus monkey showed that the regional uptake of 18F-memantine could be blocked by pharmacological doses of memantine and (+)-MK-801. In the present study, the binding characteristics of 18F-memantine was examined in five healthy volunteers. In humans, 18F-memantine was homogeneously distributed in gray matter i.e. cortex and basal ganglia regions, as well as the cerebellum. No radioactive metabolites were detected in plasma during the time-frame of the PET studies. The uptake of 18F-memantine in receptor-rich regions such as striatum and frontal cortex could be well described by a 1-tissue compartment model. The DV" values of all gray matter regions were similar and ranged from 15 to 20 ml/ml. The white matter showed lower DV" values of 15 +/- 1.4 ml/ml. These results suggest that 18F-memantine distribution in human brain does not reflect the regional NMDA receptor concentration, and therefore, this radioligand is not suitable for the PET imaging of the NMDA receptors.

Adult↗