Thomas Vogl

The Ca2+-binding proteins S100A8 and S100A9 are encoded by novel injury-regulated genes

To gain insight into the molecular mechanisms underlying cutaneous wound repair, we performed a large scale screen to identify novel injury-regulated genes. Here we show a strong up-regulation of the RNA and protein levels of the two Ca2+-binding proteins S100A8 and S100A9 in the hyperthickened epidermis of acute murine and human wounds and of human ulcers. Furthermore, both genes were expressed by inflammatory cells in the wound. The increased expression of S100A8 and S100A9 in wound keratinocytes is most likely related to the activated state of the keratinocytes and not secondary to the inflammation of the skin, since we also found up-regulation of S100A8 and S100A9 in the epidermis of activin-overexpressing mice, which develop a hyperproliferative and abnormally differentiated epidermis in the absence of inflammation. Furthermore, S100A8 and S100A9 expression was found to be associated with partially differentiated keratinocytes in vitro. Using confocal microscopy, both proteins were shown to be at least partially associated with the keratin cytoskeleton. In addition, cultured keratinocytes efficiently secreted the S100A8/A9 dimer. These results together with previously published data suggest that S100A8 and S100A9 are novel players in wound repair, where they might be involved in the reorganization of the keratin cytoskeleton in the wounded epidermis, in the chemoattraction of inflammatory cells, and/or in the defense against microorganisms.

MR imaging of the oropharynx and tongue: comparison of plain and Gd-DTPA studies.

The effect of intravenously administered gadolinium-diethylene-triamine pentaacetic acid (Gd-DTPA) on signal intensity in comparison to plain noncontrast imaging was analyzed. Sixty-one patients with diseases of the oropharynx and tongue base were examined using multiplanar magnetic resonance (MR) imaging. The contrast medium Gd-DTPA was administered in 26 cases. Thirty-eight patients also underwent CT. Forty-one patients had surgery and pathological verification. Plain MR imaging was equal or superior to CT in all except one patient. Marked contrast enhancement produced by Gd-DTPA was observed in carcinomas, sarcomas, inflamed salivary glands, and in normal pharyngeal mucosa. The usefulness of Gd-DTPA may be increased by measuring the enhancement in signal intensity versus time to allow a better differentiation of histological features.

Pulmonary sling: Morphological findings. Pre- and postoperative course

Pulmonary sling (PS) is a congenital condition in which the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA), forming a sling around the trachea causing tracheal compression. The incidence is not so rare as initially thought. Symptoms of severe airway obstruction often begin in the newborn or young infant. Echo-colour-Doppler may reveal the PS but emphysema can mask the typical findings. Deviation of fluid-filled lungs may be detected prenatally. Chest radiographs show unusual air distribution, deviation of heart and mediastinum and altered tracheobronchial angles. Bronchography and bronchoscopy demonstrate the high incidence of associated tracheal anomalies such as cartilagenous rings and long tracheal stenosis. Anterior oesophageal indentation is not always seen in the oesophogram. Magnetic resonance imaging (MRI) and computed tomography (CT) reveal the PS, but cautious interpretation is necessary because of different levels of the anomalous LPA. PS and associated cardiovascular malformations can be clearly detected by angiography. Associated extrathoracic anomalies are common. Early diagnosis and therapy of PS is mandatory and consists of reimplantation of the LPA into the pulmonary trunk and division of the ligamentum arteriosum. The postoperative course may be cumbersome necessitating bronchological interventions. Tracheal resection may be necessary but restenosis is frequent. A one-stage repair has been proposed in such cases and was successfully done in a few reported cases. Relief of respiratory obstruction is often complete when there are no associated tracheobronchial anomalies. Late postoperative course is favourable but respiratory obstructive attacks may occur with decreasing incidence over time and tracheal growth.

Three-dimensional magnetic resonance imaging in skull base lesions.

Three-dimensional (3D) magnetic resonance (MR) imaging is a new digital technique developed 2 years ago by a multidisciplinary group of head and neck surgeons, clinical radiologists, and mathematicians at the University of Munich. In this study, the clinical value of this method, which has been improved significantly during the last 9 months, is evaluated in lesions of the skull base. Our results indicate that 3D reconstruction based on two-dimensional (2D) MR images reveals topographic details of interesting structures. In addition, this method offers new possibilities for the preoperative planning of tumor resection, particularly in lesions close to the skull base. However, this imaging technique will have to be improved before it achieves widespread clinical use.

MR imaging in pediatric airway obstruction

Magnetic resonance (MR) imaging of the trachea was performed in 27 children with congenital tracheal narrowing. The diagnoses included aortic arch anomalies (n = 7), innominate artery compression (n = 13), pulmonary artery compression (n = 5), and tracheomalacia (n = 2). Demonstration of the trachea and the surrounding tissue and vessels on MR images allowed the evaluation of the cause of tracheal compression and the degree and location of collapse. Patients were examined with MR imaging if the cause of airway obstruction was still unclear after bronchoscopy. It is concluded that MR imaging is a well suited modality for characterizing tracheal narrowing without using ionizing radiation or intravenous contrast medium.

MRI with Gd-DTPA in tumours of larynx and hypopharynx

Twenty-eight patients with tumours of the larynx, divided into supraglottic, glottic, and subglottic lesions, and of the hypopharynx were examined by different MRI techniques using the paramagnetic contrast medium Gd-DTPA. The results of preoperative MRI were compared with clinical laryngoscopy and the pathological tumour classification. The examinations were carried out using plain T1-wand T2-weighted and Gd-DTPA enhanced T1-weighted sequences. Most studies included three slice orientations for optimal assessment of different tumour locations. The most accurate diagnostic information was given by Gd-DTPA-enhanced sequences. The combination of plain images, contrast-enhanced images and subtraction enabled precise assessment of deep infiltration. T2-weighted and proton density sequences conveyed more information about cartilage invasion and liquid-filled structures, but gave more artefacts than T1-weighted images. Laryngoscopy had advantages in T1-classified tumors, as the extent of the tumor could be seen, and offered histological information via biopsy. Diagnostic findings of MRI correlated in 85.7% with the pathologists report, and laryngoscopy provided exact classification in only 64.3% of patients. Gd-DTPA-enhanced MRI is an important adjunct to non-contrast MR studies, and forms an ideal diagnostic supplement to laryngoscopy.

Endovascular treatment of traumatic arterio-venous fistulas of the vertebral artery.

Cervical vertebral artery fistulas are rare arteriovenous malformations between the vertebral artery and veins of the neighbourhood. The etiology of the fistulas may be traumatic or spontaneous. Management and the results in two patients with large arterio-venous fistulas of the cervical vertebral artery with severe deterioration of spinal function by using the detachable balloon technique are discussed. Complete angiographic and clinical cure was achieved in both patients and no complications related to the embolization procedure occured. The detachable balloon technique is an effective method for selective occlusion of the fistula. Good radiographic monitoring facilities are required to make endovascular procedures effective and safe.

3D MR imaging with Gd-DTPA in head and neck lesions

Three-dimensional MR imaging technique is not a new concept, however, there is very little experience concerning clinical trials. Especially in head and neck lesions, the accuracu of this new imaging method has not yet been tested. A pilot study was performed to evaluate the diagnostic value of demonstrating the head and neck lesions and topographical structures implemented in a three-dimensional reconstruction of the entire head. The 3D reconstruction mode is based on the ray-tracting model. The application of the contrast medium Gd-DTPA proved to be helpful. Three-dimensional reconstruction revealed clear topographic details of the lesions, including the spread of infiltration and destruction of soft tissue. Additionally, the simultaneous view of multiple slices in different orientations is an ideal method for evalauting the spread of the lesion and to visualize the relation between lesion and surrounding tissue.