Recently developed versatile biodegradable polymeric biomaterial offer new therapeutic options in numerous medical fields. Biocompatibility is a crucial requirement for the biomedical application of biomaterials, including the sterilization of these materials with the use of accepted protocols. Ethylene-oxide (EO) and low-temperature plasma (LTP) sterilization are frequently used low-temperature sterilization technologies for heat-sensitive materials. The agarose diffusion assay is a recommended cell-screening test to assess the cytotoxicity of biomaterials in vitro. The sensitivity of the agarose assay can be increased by using a modified computer-based image-analysis system. The influence of EO and LTP sterilization on the cytotoxicity of a versatile polymer system of shape-memory polymer networks based on oligo (epsilon-caprolactone) dimethacrylate and n-butyl acrylate was investigated. Statistically significant differences in the rate of cell lysis after EO and LTP sterilization of the polymer samples were detected by using this modified quantification system. The influence of the different sterilization techniques on the cytotoxicity of the polymeric material, as well as the clinical relevance of the described differences, are discussed.
Biomaterial research and tissue engineering are rapidly growing scientific fields that need an interdisciplinary approach where clinicians should be included from the onset. Biocompatibility testing in vitro and in vivo comprise the agarose-overlay test, the MTT test, direct cell seeding tests and the chorioallantoic membrane test for angiogenic effects, among others. Molecular biology techniques such as real-time polymerase chain reaction and microarray technology facilitate the investigation of tissue integration into biomaterials on a cellular and molecular level. The physicochemical characterization of biomaterials is conducted using such methods as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Excellent biocompatibility and biofunctionality were demonstrated for a series of recently developed multifunctional biodegradable, polymeric biomaterials both in vitro and in vivo. Novel, multifunctional polymeric biomaterials offer a highly specific adjustment to the physiological, anatomical and surgical requirements and can thereby facilitate new therapeutic options in head and neck surgery.
The vascularity of cervical lymph nodes can be documented by means of color-coded duplex sonography and malignant and benign lymph nodes distinguished on the basis of typical patterns of vascularity. However, not all intranodal vessels can be visualized by color-coded duplex sonography, and minute vessels are detectable only after the administration of a signal enhancer. This also makes it possible to assess the morphology of cervical lymph nodes that are inaccessible on plain sonography. In the present study we examined acute and chronic inflammatory and metastatic lymph nodes as well as malignant lymphomas to determine the extent to which a specific pattern of vascularity can be detected with color-coded duplex sonography after the injection of Levovist as a signal enhancer. In addition, digital image processing was used to quantify the vascularity detected in relation to the cross-sectional area of the lymph nodes as seen at sonography and to determine whether there are any differences in lymph node types as regards an increase in the detection of vascularity. After injection of the marker a typical pattern of vascularity could be assigned to all lymph nodes examined and differences shown in quantifying vascularity: This increase was greatest in the acutely inflamed lymph nodes (36.0 +/- 5.0%) and smallest in lymph nodes with chronic inflammation (2.3 +/- 1.3%). These findings show that cervical lymph nodes of varying origin differ by virtue of their pattern of vascularity, with increased vascularity detectable after administration of a signal enhancer.
In contrast to CT and MRI, conventional B-scan echography is quick and easy to perform, cheap, and without side effects. The disadvantage is the limited field of view. This may result in a loss of information between the dynamic examination and the documentation. With SieScape a new technology was developed to address these problems. It allows one to obtain any imaging slices from the head and the neck. This technique is the first to allow a topographical orientation based on B-scan images. This study presents the application of SieScape, and demonstrates normal and abnormal findings. Initial experience with the new technology indicates that SieScape is an alternative to other methods such as CT and MRI.
Sl'MMARY: Shape-memory polymers have a high potcntial lor applications in several surgical fielcls. The tiK'oiporatton of a biomaterial in vivo is assumed to regulär vvound healing mechanisms and ailequ.ile angiogenesis. In this study we were interested in the inlluenee of our novel polymer on the angiogenesis and the wound healing after subcutaneous Implantation of polymer samples in rats. The angiogenesis was investigated by using the chorionallantois membrane (CAM) assay. MMP-and TIMP-expression was analyzed äs key parameters of wound healing. The angiogenesis of the CAM was not influenced by the polymer samples. The kinetic of appearance and activity levels of MMPs and TIMPs did not show statistieally signitlcant differences between the polymer and the control group. HNI.HTUNG r-ormgecläehtnispolymere sind Stimuli-sensitive Materialien, die ein hohes Anwendungspotential im Bereich der minimalinvasiven Chirurgie haben. Die (JeWebeintegration eines Biomaterials in vivo erfordert eine adäquate Angiogenese sowie eine reguläre Wundheilung. Diese Prozesse setzen eine kontrollierte Degradation der Extrazellulärmatrix voraus, die wesentlich durch die Balance zwischen Matrix Metalloproteinasen (MMPs) und ihren endogenen Inhibitoren (Tissue Inhibitor of Metalloproteinases, TIMPs) reguliert wird. MATERIAL UND METHODEN Auf der Basis von Oligo(e-caprolacton)dimethacrylaten, die das teilkristalline Schaltsegment bilden, und n-Butylacrylat als Comonomer wurde ein Polymersystem mit einer AB-Netzwerkstruktur entwickelt 1 . Die Proben wurden mittels Ethylenoxidsterilisation sterilisiert. Befruchtete Hühnereier wurden in einem Inkubator bei 37 °C und einer Luftfeuchtigkeit von 65-70% inkubiert. Nach dreitägiger Inkubation wurden die Eierschale unter sterilen Bedingungen eröffnet, die Hühnerembryos in eine Petrischale überfuhrt und in einem Zellkulturinkubator bei 37 °C inkubiert. Auf die vaskularisierte Chorioallantoismembran (CAM) wurde eine sterilisierte Polymerprobe plaziert und für 48 h inkubiert. Anschließend wurde die Vaskularisation der CAM, die durch das Polymer gut sichtbar war, makroskopisch und mikroskopisch beurteilt. Die Tierversuche erfolgten mit Genehmigung des Animal Care and Use Committee of the Department of Surgery, Children's Hospital, Boston, USA. Die sterilen Polymerproben wurden subkutan am Rücken von Sprague-Dawley Ratten (Gewicht zwischen 176-220 gr.) implantiert. Kontralateral wurde die identische Wundinzision ohne Polymerimplantation durchgeführt. Nach 2-, 5-und 14-tägiger Implantationsdauer wurden das Wundgewebe entnommen und die MMP-1-, MMP-2-und TIMP-Expression analysiert. Die Durchführung der SDS-Substrat-Gelelektrophorese (Zymographie) zum Nachweis der MMP-2-Expression erfolgte wie in der Literatur beschrieben [2]. Die MMP-1-und TIMPExpression wurde mit Hilfe eines radiometrischen Enzymassays bestimmt [3]. ERGEBNISSE In keinem der durchgeführten CAM Experimente kam es zu einem Absterben des Hühnerembryos. Die Quantifizierung der Gefäße der CAM ergab keine statistischen Differenzen zwischen der Po...
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