Intradermal tacrolimus prevent scar hypertrophy in a rabbit ear model: a clinical, histological and spectroscopical analysis.

BACKGROUND: Keloids and hypertrophic scars (HSc) affect 4.5-16% of the population. Thus far, the different approaches of keloid treatment are not very efficient, with a 50% relapse rate and many ongoing researches are looking for simple, safe and more efficient therapeutic methods. Tacrolimus is an immunomodulator that could be useful in treating keloid. OBJECTIVES: The objective of this study is to evaluate the effectiveness of Tacrolimus in inhibiting HSc formation on rabbits' ears model and to check optical skin spectroscopy in tissue characterization. METHODS: Our study was carried out on 20 New-Zealand female white rabbits. HSc were obtained by wounding rabbits' ear. These wounds were treated with intradermal injections of tacrolimus (0.2-0.5 mg/cm(2)) or a vehicule. The assessment of treatment efficacy was performed by clinical examinations, histological assay and skin spectrometry. RESULTS: Tacrolimus did not induce general or local side-effects. The scar elevation index in treated subjects was half less than that of the untreated ones. Furthermore, dermal thickness and inflammatory cellular density were both significantly smaller for treated scars than for the control ones. In vivo optical skin spectroscopy can characterize hypertrophic and normal skin with high sensibility and specificity. CONCLUSION: Intradermal injection of tacrolimus at 0.5 mg/cm(2) is an efficient way to prevent HSc in our experiment model and its tolerance is correct. Optical spectroscopy could be a good non-invasive tool to evaluate HSc treatment. These promising results might be proposed for patients suffering from keloid.

Fast construction of panoramic images for cystoscopic exploration.

Cystoscopy is used as a reference clinical examination in the detection and visualization of pathological bladder lesions. Evolution observation and analysis of these lesions is easier when panoramic images from internal bladder walls are used instead of video sequences. This work describes a fast and automatic mosaicing algorithm applied to cystoscopic video sequences, where perspective geometric transformations link successive image pairs. This mosaicing algorithm begins with a fast initialization of translation parameters computed by a cross-correlation of images, followed by an iterative optimization of transformation parameters. Finally, registered images are projected onto a global common coordinate system. A quantifying test protocol applied over a phantom yielded a mosaicing mean error lower than 4 pixels for a 1947 x 1187 pixels panoramic image. Qualitative evaluation of 10 panoramic images resulting from videos of clinical cystoscopies was performed. An analysis performed over translation values from these clinical sequences (in vivo) is used to modify the mosaicing algorithm to be able to do a dynamic selection of image pairs. Construction time of panoramic images takes some minutes. At last, algorithm limits are discussed.