Cone-Beam Computed Tomography (CBCT) dacryocystography for imaging of the nasolacrimal duct system.

PURPOSE: To evaluate the usefulness and safety of cone-beam computed tomography (CBCT) dacryocystography in detecting lesions, identifying coexisting soft-tissue changes and determining treatment options in patients with epiphora. PATIENTS AND METHODS: Unilateral digital subtraction dacryocystography and CBCT dacryocystography were carried out on 45 patients. Stenoses and occlusions were identified and coexisting changes such as septal deviation and dacryoliths were noted. The diameter of the bony lacrimal duct of affected and unaffected side was measured and related to the clinically evident epiphora. An attempt was made to base the subsequent therapeutic planning on the CBCT dacryocystographic findings. Additionally, the radiation dose levels for CBCT dacryocystography in comparison to those of multislice computed tomography (MSCT) were evaluated in a standardized head-neck Rando-Alderson phantom. RESULTS: Nasolacrimal duct obstructions were present in 37/45 patients, 18 with a stenosis and 19 with an occlusion in parts of the lacrimal outflow system. The minimal bony diameter of the side with epiphora was significantly decreased compared to the unaffected side. Coexisting soft-tissue changes did not correlate significantly with the clinical sign of epiphora. Eight patients showed no underlying reason for the epiphora and were treated conservatively. A total of eleven patients received interventional therapy for their stenosis and 23 patients had to be treated surgically. A further three patients received medical treatment for infection, before surgery and interventional therapy, respectively, were carried out. Dose levels for CBCT imaging remained far below those of MSCT. CONCLUSION: CBCT dacryocystography is a safe and time-efficient modality for assessing the nasolacrimal duct system in patients with epiphora. CBCT dacryocystography provides detailed images of the nasolacrimal drainage system, surrounding soft tissue, and bony structures in one diagnostic tour. It allows clear measurement of the bony nasolacrimal duct and displays information beyond that of the drainage lumen, improving the planning of therapeutic interventional and surgical procedures.

Evaluation of hypoxia-mediated growth factors in a novel bladder cancer animal model.

BACKGROUND AND AIM: The outcome of advanced transitional cell carcinoma (TCC) is poor. Changes taking place in the tumor microenvironment are receiving increased scrutiny. Hypoxia is the key to increased expression of HIF-1alpha (hypoxia-inducible factor 1alpha) resulting in increased expression of growth factors (e.g. vascular endothelial growth factor (VEGF), epidermal growth factor (EGF)). The aim of our study was to establish an animal model with modulatable tumor hypoxia. Resulting tumor growth and growth factors were assessed. MATERIALS AND METHODS: Low Hb levels were induced in rats by total body irradiation (5 Gy). Twenty animals received EPO erythropoietin (EPO), 1000 IE/kg/week subcutaneously). After subcutaneous injection of NBT-II cells a weekly determination of Hb concentration, leukocyte counts and tumor volume were performed. Serum VEGF levels were quantified and oxygen Hb saturation in healthy tissue and tumors were measured by percutaneous laser spectroscopy. HIF-1alpha and VEGF were examined immunohistochemically. RESULTS: Reduced O2 supply promoted expression of HIF-1alpha and VEGF. Low oxygen availability was essential for tumor growth. EPO improved the O2 supply and decreased expression of growth factors but did not reduce tumor volumes. CONCLUSION: Based on these studies, treatment of low Hb levels appears reasonable in TCC. O2 supply is improved and expression of tumor growth factors is decreased. Tumor volumes did not differ between the groups, causatively adverse effects of EPO overtreatment might negatively affect microcirculation. Restoring low Hb levels and improvement in the O2 supply resulted in tumor shrinkage.

The vast majority of bone-marrow-derived cells integrated into mdx muscle fibers are silent despite long-term engraftment.

Bone-marrow-derived cells can contribute nuclei to skeletal muscle fibers. However, serial sectioning of muscle in mdx mice implanted with GFP-labeled bone marrow reveals that only 20% of the donor nuclei chronically incorporated in muscle fibers show dystrophin (or GFP) expression, which is still higher than the expected frequency of "revertant" fibers, but there is no overall increase above controls over time. Obviously, the vast majority of incorporated nuclei either never or only temporarily turn on myogenic genes; also, incorporated nuclei eventually loose the activation of the beta-actin::GFP transgene. Consequently, we attempted to enhance the expression of dystrophin. In vivo application of the chromatin-modifying agents 5-azadeoxycytidine and phenylbutyrate as well as local damage by cardiotoxin injections caused a small increase in dystrophin-positive fibers without abolishing the appearance of "silent" nuclei. The results thus confirm that endogenous repair processes and epigenetic modifications on a small-scale lead to dystrophin expression from donor nuclei. Both effects, however, remain below functionally significant levels.