Dieter Schumann

Nanocelluloses as Innovative Polymers in Research and Application

Cellulose is a fascinating and almost inexhaustible and sustainable natural polymeric raw material characterized by exciting properties such as hydrophilicity, chirality, biodegradability, broad chemical-modifying capacity, and the formation of different semicrystalline fiber morphologies. If cellulosics such as bacterial cellulose or strongly disintegrated wood cellulose are composed of nanosized fibers and the nanofiber structuring determines the product properties, these polymers are described as nanocelluloses. Because of the extraordinary supramolecular structure and exceptional product characteristics as high-molecular and high-crystalline cellulosics with a water content up to 99%, nanocelluloses require increasing attention. This review assembles the current knowledge in research, development, and application in the field of nanocelluloses through examples. The topics combine selected results on nanocelluloses from bacteria and wood as well as their use as technical membranes and composites with the first long-time study of cellulosics in the animal body for the development of medical devices such as artificial blood vessels, and the application of bacterial nanocellulose as animal wound dressings and cosmetic tissues.

Cytokeratin pattern of clinically intact and pathologically changed oral mucosa

The various cytokeratin polypeptides in oral epithelia are expressed in dependence on site and formation of a stratum corneum. Certain cytokeratins occur permanently and others occasionally. In fibrous hyperplasia and Lichen ruber planus, patterns of cytokeratins did not deviate significantly from normal. In some but not all cases of squamous cell carcinoma and leukoplakia studied, marked aberrations of pattern were characterized by (i) appearance of cytokeratin No. 19, (ii) somewhat more frequent occurrence of cytokeratins Nos. 8 and 18, (iii) proteolytic modifications of cytokeratins, and (iv) partial loss of a few site-specific cytokeratins. The aberrations may be taken as additional diagnostic criteria for differentiation between non-aggressive and potentially aggressive leukoplakic lesion, even if they are not correlated with the conventional histological grading of dysplasia.

Bacterial nanocellulose as a new patch material for closure of ventricular septal defects in a pig model.

OBJECTIVES Current materials for closure of cardiac defects such as ventricular septal defects (VSDs) are associated with compliance mismatch and a chronic inflammatory response. Bacterial nanocellulose (BNC) is a non-degradable biomaterial with promising properties such as high mechanical strength, favourable elasticity and a negligible inflammatory reaction. The aim of this study was the evaluation of a BNC patch for VSD closure and the investigation of its in vivo biocompatibility in a chronic pig model. METHODS Youngs modulus and tensile strength of BNC patches were determined before and after blood exposure. Muscular VSDs were created and closed with a BNC patch on the beating heart in an in vivo pig model. Hearts were explanted after 7, 30 or 90 days. Macropathology, histology and immunohistochemistry were performed. RESULTS Youngs modulus and tensile strength of the BNC patch decreased after blood contact from 6.3 ± 1.9 to 3.86 ± 2.2 MPa (P < 0.01) and 0.33 ± 0.06 to 0.26 ± 0.06 MPa (P < 0.01), respectively, indicating the development of higher elasticity. Muscular VSDs were closed with a BNC patch without residual shunting. After 90 days, a mild chronic inflammatory reaction was present. Moreover, there was reduced tissue overgrowth in comparison with polyester. Proceeding cellular organization characterized by fibromuscular cells, production of extracellular matrix, neoangiogenesis and complete neoendothelialization were found. There were no signs of thrombogenicity. CONCLUSIONS BNC patches can close VSDs with good mid-term results and its biocompatibility can be considered as satisfactory. Its elasticity increases in the presence of blood, which might be advantageous. Therefore, it has potential to be used as an alternative patch material in congenital heart disease.

Die diagnostische Wertigkeit der Nasometrie – eine repräsentative Studie für Patienten mit Lippen-Kiefer-Gaumensegel-Spalten und Gesunde

In the rehabilitation of cleft palate patients the quality of spoken language represents one of the most important aspects of successful social integration. It is therefore necessary to direct special attention to phoniatric care and speech therapy following operative reconstruction. One of the main problems is the comparison of subjective and objective measures of the degree and type of nasal disorder. In an interdisciplinary project at the University of Jena nasometry was assessed. Due to a lack of norm values for German a representative sample for the calibration of cleft palate patients and normal subjects was collected. Speech was elicited using standardized and phonetically validated reading materials. Nasalance measurements were compared with judgements made by a group of trained listeners who were asked to assess voice quality (RBH) and nasality. A database containing nasalance values and acoustic signals from 120 subjects was built up. The results generally exhibited highly significant correlations between instrumental measurements and auditory judgements. Profiles of norm values for a phonetically and statistically reliable standard for German were obtained, which in turn can be used as a comparative basis for further studies.

Der traumatische Ohrmuschelverlust

ZusammenfassungEs werden die Möglichkeiten der Ohrrekonstruktion nach partiellem Ohrverlust erörtert und an drei Fallbeispielen demonstriert. Wichtig erscheint, daß bei traumatischem Ohrverlust das Amputat geborgen wird und mit dem Patienten zur Sofortversorgung in eine spezialisierte Klinik (für Plastische Chirurgie, Mund-Kiefer-Gesischts-Chirurgie, HNO) verlegt werden sollte. Unter günstigen Bedingungen sollte die mikrochirurgische Replantation bzw. die avaskuläre Replantation erwogen werden.Sind die Gegebenheiten ungünstig, sollte die modifizierte Pocket-Methode oder die Methode nach Park (1995) Verwendung finden, um zumindest die Helix zu erhalten. Als Alternative wird beim partiellen Ohrverlust die Ohrrekonstruktion empfohlen.AbstractThe possibilities of ear reconstruction after a partial loss of the external ear are demonstrated and are discussed according to 3 clinical cases. After a traumatic amputation of the ear, it is of importance to salvage the amputate and to send it together with the patient to a specialized clinic (head and neck surgery or plastic surgery) for immediate reconstruction. Under appropriate conditions, a microsurgical or an avascular replantation should be taken into consideration. If this is not possible, the pocket-method or the method of Park (1995) should be applied to maintain the helix. Alternatively, the reconstruction of the ear is advised after a loss of the ear.