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Biomedical subjects

D Schumann

Publications and source records attributed to D Schumann.

At least 19 recordsLinked to original sources
PubMed2006

Vertical distraction of fibula transplant in a case of mandibular defect caused by shotgun injury.

This case demonstrates the successful aesthetic and functional reconstruction of a complex facial gun-shot injury with extended bone defects and soft tissue destructions using a 3-step procedure. Initially, a reconstruction plate was inserted, later a fibula transplant enabled the basic reconstruction and finally was distructed in a 3rd session. The rationale behind the sequencing of surgical sessions was the extended bony defect and soft-tissue destruction. The main problem in this type of wound is hypoxia or anoxia of the receptor bed for the transplant. A microvascular anastomosized bone transplant is necessary for sufficient oxygen tension in the recipient site. The anatomical dimensional disproportion of the transplanted free fibula graft and the shape of the mandible were corrected prior to the insertion of dental implants by means of vertical distraction.

Bone Plates↗
PubMed2006

[Bidirectional and unidirectional distraction of defects of the alveolar process comparative clinical study].

AIM: The purpose of the retrospective study was to compare bidirectional distraction osteogenesis with the currently used unidirectional method of alveolar ridge distraction with regard to bone height attained and complications. PATIENTS AND METHODS: Overall 21 patients were treated by distraction osteogenesis for localized defects of the alveolar ridge. Vertical augmentation of the mandible and maxilla was performed using 10 unidirectional (group A) and 12 bidirectional (group B) devices. The effect of therapy was evaluated by height of bone gain and observed complications. RESULTS: The average gain of vertical bone height was approximately 6 mm. No statistically significant differences occurred between the two treatment groups (p=0.09). For the entire study two complications were observed: beside breakage of a distractor device (unidirectional distraction) an infection during the retention time (bidirectional distraction) developed. CONCLUSIONS: It could be shown that osteodistraction is a potentially valuable therapy for the correction of alveolar defects. We observed complications in both groups. No statistical differences were noted in regard to gained bone height and complications between the two groups.

Adult↗
PubMed2006

[Evaluation of individual ceramic implants made of Bioverit with CAD/CAM technology to reconstruct multidimensional craniofacial defects of the human skull].

BACKGROUND: Restrictions in the bone structure of the craniomandibular region caused by malformation, traumata or malignant tumours are currently of interest in reconstructive oral and maxillofacial surgery. Methods of autologous bone transplantation are well established for reconstruction of those defects. The reconstruction and remodeling of contour-shaping defects is more difficult due to atrophy and resorption of free-transplantable tissues. Artificially induced harmful effects have been reported on harvesting in the donor area. Further available methods of alloplastic reconstruction are computer-assisted design and manufacturing systems (CAD/CAM). The advantages of individual design and fabrication are obvious in the manufacturing of defect-specific implants. MATERIAL AND METHODS: In the present study the application of individual CAD-based reconstructed bioceramic implants made of Bioverit II was evaluated in the region of the facial skull. Clinical results, patient acceptance and the analysis of the postoperative observation period of 30 months are reviewed. RESULTS: Altogether 25 individual Bioverit ceramics were implanted in the facial region. All patients were satisfied with the aesthetic results of the implantations after primary surgery. Three patients developed a need for further correction during the observation period; one implant fracture was observed. CONCLUSION: Finally, it can be stated that the preoperative expenditures in time, experts, technology and fabrication of individual CAD/CAM planned and manufactured implants are justified by the following advantages: fixed volume, reduced operating time, lack of donor morbidity, easy subsequent treatment of the material and the aesthetic results achieved.

Adult↗
PubMed2006

Mechanobiological conditioning of stem cells for cartilage tissue engineering.

Articular cartilage possesses little capacity for endogenous repair after having been damaged by disease or trauma. Various surgical procedures depending on ingrowth of mesenchymal stem cells into the defects showed repair with fibrocartilage which is of minor quality and less resistant against physical forces. New treatment options using Tissue Engineering strategies for cartilage repair showed intriguing results. Human mesenchymal stem cells (MSC) isolated from bone marrow are becoming increasingly recognized for their potential to generate different cell types and thereby function effectively in vitro or in vivo in tissue repair. Incorporation of MSCs in suitable tissue engineering scaffolds and culture in chondrogenic medium can produce cartilage-like tissue. MSCs can be harvested from bone marrow by a small puncture of the iliac crest of patients. In contrast to chondral based repair this small procedure creates no additional harvest defect in the knee joints of the patient. Numerous publications show the beneficial influence of mechanobiological conditioning (e.g. mechanical compression, hydrostatic pressure, osmotic, shear, ultrasound) on the chondrogenic differentiation of dedifferentiated chondrocytes. In contrast to chondrocytes and cartilage explants there are few studies that examine the influence of mechanobiological stress on mesenchymal progenitor cells undergoing chondrogenesis. Using an in vitro aggregate culture system enhanced chondrogenesis of mesenchymal progenitor cells, detected by an increased extracellular matrix deposition of collagen and aggrecan, could be shown under repeated cyclic hydrostatic pressure. Similar results, with an increase in chondrogenic differentiation of mesenchymal progenitor cells could be detected, when the cells were loaded in three-dimensional matrices and subjected to cyclic, compressive load or low-intensity pulsed ultrasound. This review will summarize the current state of knowledge in the field of mechanobiological conditioning of mesenchymal stem cells and its possible clinical application.

Animals↗
PubMed2003

[Video-assisted endoscopic sinus revision for treatment of chronic, unilateral odontogenic maxillary sinusitis].

BACKGROUND: The proportion of dental causes of maxillary sinusitis is estimated between 10% and 40%. The mechanisms are manifold and originate from the close relation of the side teeth and the maxillary sinus. In the past, the transantral approach was commonly used by maxillofacial surgeons as their first choice. PATIENTS AND METHODS: Between 01/1999 and 10/2001 38 patients underwent endoscopic surgery controlled via the fossa canina. Apart from the mandatory treatment of the dental focus and the mucosal pathologies, a fenestration to the middle meatus of the nose was performed in 7 cases. RESULTS AND CONCLUSION: The dental medical history, OPG, CT scans in coronary plane, endoscopic findings, and histology showed the commonly "silent" course of dental sinusitis. Typical findings in CT scans are unilateral basal maxillary opacities adjacent to the molar and premolar teeth. In 20% of the cases there was also a blockade of the infundibulum. All patients were reexamined 6-12 months postoperatively. The patients are free of symptoms, but sometimes suffer from headaches. An exact diagnosis and the clear separation of rhinogenic causes are vital points for the therapy of dental sinusitis. In cases of unilateral sinusitis, a comprehensive investigation by the maxillofacial surgeon should be recommended. Video-assisted endoscopic sinus revision is preferable to the transantral approach and is especially suitable for the treatment of mucosal retention cysts, the removal of foreign bodies, endoscopically controlled resections of apical roots, elevations of the sinus floor, and dental implants. If the ethmoidal infundibulum and maxillary ostium are open, no fenestration is needed. In cases of blockade, fenestration to the middle nose canal is indicated.

Bicuspid↗
PubMed2001

Carcinoembryonic antigen cell adhesion molecule 1 directly associates with cytoskeleton proteins actin and tropomyosin.

CEA cell adhesion molecule 1 (CEACAM1), a type 1 transmembrane and homotypic cell adhesion protein belonging to the carcinoembryonic antigen (CEA) gene family and expressed on epithelial cells, is alternatively spliced to produce four major isoforms with three or four Ig-like ectodomains and either long (CEACAM1-L) or short (CEACAM1-S) cytoplasmic domains. When murine MC38 (methylcholanthrene-induced adenocarcinoma 38) cells were transfected with human CEACAM1-L and stimulated with sodium pervanadate, actin was found to co-localize with CEACAM1-L at cell-cell boundaries but not in untreated cells. When CEACAM1-L was immunoprecipitated from pervanadate-treated MC38/CEACAM1-L cells and the associated proteins were analyzed by two-dimensional gel analysis and mass spectrometry, actin and tropomyosin, among other proteins, were identified. Whereas a glutathione S-transferase (GST) fusion protein containing the l-isoform (GST-Cyto-L) bound poorly to F-actin in a co-sedimentation assay, the S-isoform fusion protein (GST-Cyto-S) co-sedimented with F-actin, especially when incubated with G-actin during polymerization (K(D) = 7.0 microm). Both GST-Cyto-S and GST-Cyto-L fusion proteins bind G-actin and tropomyosin by surface plasmon resonance studies with binding constants of 0.7 x 10(-8) and 1.0 x 10(-7) m for GST-Cyto-L to G-actin and tropomyosin, respectively, and 3.1 x 10(-8) and 1.3 x 10(-7) m for GST-Cyto-S to G-actin and tropomyosin, respectively. Calmodulin or EDTA inhibited binding of the GST-Cyto-L fusion protein to G-actin, whereas calmodulin and G-actin, but not EDTA, stimulated binding to tropomyosin. A biotinylated 14-amino acid peptide derived from the juxtamembrane portion of the cytoplasmic domain of CEACAM1-L associated with both G-actin and tropomyosin with K(D) values of 1.3 x 10(-5) and 1.8 x 10(-5) m, respectively. These studies demonstrate the direct interaction of CEACAM1 isoforms with G-actin and tropomyosin and the direct interaction of CEACAM1-S with F-actin.

Actins↗
PubMed2001

[Long-term results of the reduction mammaplasty with Revers T-technique].

Functional and aesthetic aspects make the reduction mammaplasty a favoured surgical procedure. The vertical technique, as well as the technique with central pedicle have clearly gained in importance next to the traditional T-cut technique. We provided questionnaires to a random sample of 110 patients who had been treated according to the method of Strömbeck-Weiner. The results were evaluated and compared with the literature. Our results show that the functional complaints were largely eliminated by the surgery and that the patients experienced a significant improvement in their psychological well being. The applied method produces a satisfactory shape of the breast with programmed ptosis, and to large extent retains the nipple-areola sensitivity. One shortcoming of this procedure is the scar formation which 20 % of the patients found bothering. However, 94 % of the patients would choose the procedure again. We conclude that the reduction mammaplasty with reverse T-technique according to Strömbeck-Weiner continues to be of value for patients with a desired weight reduction of more than 500-600 g and patients over the age of fourty.

Adolescent↗
PubMed2000

[Burns].

The therapy for burn injuries has established a definable management: percentage of the body surface area burned and thickness are important for the method of treatment (ambulant, on ward, intensive burn center). Open and close wound care with different bandages, in combination with primary surgery, has increased the probability of survival. A special problem is the aesthetics and function of the head and neck area. Hypertrophy and keloid scars may be disturbing, especially in children who have had a scald accident (41.2% of cases were children up to 5 years of age). The possibilities of correction are multiple: conservative therapy (bandages, ointment treatment, physical therapy) or surgical intervention with free skin transplantation or difficult flaps (pedicle flap, free graft, expanded flap, and microvascular anastomosed flap). The aim of research is also to cover large defects with skin culture from small donor areas. It is necessary to establish maxillofacial and plastic surgery from the beginning of the treatment for aesthetic and functionally acceptable results.

Adolescent↗
PubMed1999

Synthesis and cytotoxic evaluation of cycloheximide derivatives as potential inhibitors of FKBP12 with neuroregenerative properties.

On the basis of the new finding that the protein synthesis inhibitor cycloheximide (1, 4-[2-(3, 5-dimethyl-2-oxocyclohexyl)-2-hydroxyethyl]-2,6-piperidinedione) is able to competitively inhibit hFKBP12 (K(i) = 3.4 microM) and homologous enzymes, a series of derivatives has been synthesized. The effect of the compounds on the activity of hFKBP12 and their cytotoxicity against eukaryotic cell lines (mouse L-929 fibroblasts, K-562 leukemic cells) were determined. As a result, several less toxic or nontoxic cycloheximide derivatives were identified by N-substitution of the glutarimide moiety and exhibit IC(50) values in the range of 22.0-4.4 microM for inhibition of hFKBP12. Among these compounds cycloheximide-N-(ethyl ethanoate) (10, K(i) = 4.1 microM), which exerted FKBP12 inhibition to an extent comparable to that of cycloheximide (1), was found to cause an approximately 1000-fold weaker inhibitory effect on eukaryotic protein synthesis (IC(50) = 115 microM). Cycloheximide-N-(ethyl ethanoate) (10) was able to significantly speed nerve regeneration in a rat sciatic nerve neurotomy model at dosages of 30 mg/kg.

Animals↗
PubMed1999

[Partial loss of the auricle: multiphase reconstruction and complete preservation of the helix].

The loss of the auricle is a dramatic event in terms of aesthetics of the face. Secondary reconstruction of the ear is difficult and complicated. Therefore, a replantation of the amputated part should be tried. Proper securing and transport of the amputate is essential, in addition to the patient being sent to a specialized clinic. An anatomically correct form of the auricle is necessary for successful reconstruction of the ear. The amputated auricular cartilage is denuded of the skin except for the helical portion and is inserted into a retroauricular pocket. The helix is treated as a composite graft. After 1 to 2 months, the replanted auricular cartilage is elevated, adapted to the remaining ear stump and covered with a skin graft retroauricularly. By means of a representative case, a replantation method is demonstrated which allows complete reconstruction of the helix. In consequence, the replanted ear does not show any deficits compared with the original state.

Child↗
PubMed1999

Expression and characterization of bispecific single-chain Fv fragments produced in transgenic plants.

We describe the expression of the bispecific antibody biscFv2429 in transgenic suspension culture cells and tobacco plants. biscFv2429 consists of two single-chain antibodies, scFv24 and scFv29, connected by the Trichoderma reesi cellobiohydrolase I linker. biscFv2429 binds two epitopes of tobacco mosaic virus (TMV): the scFv24 domain recognizes neotopes of intact virions, and the scFv29 domain recognizes a cryptotope of the TMV coat protein monomer. biscFv2429 was functionally expressed either in the cytosol (biscFv2429-cyt) or targeted to the apoplast using a murine leader peptide sequence (biscFv2429-apoplast). A third construct contained the C-terminal KDEL sequence for retention in the ER (biscFv2429-KDEL). Levels of cytoplasmic biscFv2429 expression levels were low. The highest levels of antibody expression were for apoplast-targeted biscFv2429-apoplast and ER-retained biscFv2429-KDEL that reached a maximum expression level of 1.65% total soluble protein in transgenic plants. Plant-expressed biscFv2429 retained both epitope specificities, and bispecificity and bivalency were confirmed by ELISA and surface plasmon resonance analysis. This study establishes plant cells as an expression system for bispecific single-chain antibodies for use in medical and biological applications.

Antibodies, Bispecific↗
PubMed1998

A microscale electrospray interface incorporating a monolithic, poly(styrene-divinylbenzene) support for on-line liquid chromatography/tandem mass spectrometry analysis of peptides and proteins.

A methodology is described for creating a monolithic chromatography support within a pulled fused-silica electrospray needle. The monolith was formed from a mixture of styrene, divinylbenzene, 1-dodecanol, and toluene using 2,2'-azobis(isobutyronitrile) as the catalyst. The mixture was loaded into 150-micron-i.d. fused-silica capillary tubing with a pulled 5-10-micron needle tip at one end. Polymerization at 65 degrees C followed by removal of the porogen material yielded a stable, porous, monolithic support which had excellent properties for the separation and on-line, electrospray, mass spectrometry analysis of peptides and proteins. The performance of the monolith-filled electrospray needles was compared with similar needles filled with commercial C18 silica and polymeric particulate supports. Separation efficiencies for both protein and peptide mixtures were generally equal to or better than the particulate supports at comparable pressures and flow rates. The ion chromatograms derived from the on-line MS analysis were remarkably free from chemical background signals that often complicate the LC/MS analysis of femtomole amounts of sample. Good sequence coverage was obtained by LC/MS/MS analysis of the peptide mixture obtained from a protein isolated by silver-stained gel electrophoresis. The capability of the monolith to do peak parking experiments was demonstrated by the characterization of an immunoreactive HPLC fraction. The simple fabrication method, chromatographic performance, and robust nature of these microscale integrated column electrospray sources make them ideally suited for high-sensitivity tandem LC/MS analyses.

Amino Acid Sequence↗
PubMed1997

[Basaloid squamous epithelial carcinoma (basaloid-squamous carcinoma) of the mouth floor. Differential diagnosis and response to neoadjuvant chemotherapy].

The basaloid squamous cell carcinoma (BSCC) is a variant of squamous cell carcinoma, having histologically distinctive features and appearing in the oral cavity, upper respiratory tract and esophagus. Histological hallmarks are the presence of a basaloid component in intimate association with squamous cell carcinoma. The basaloid component is characterized by tightly packed nests of cells with scant cytoplasm and hyperchromic nuclei without visible nucleoli and an increased mitosis rate. Basaloid squamous cell carcinoma is said to have a higher malignant potential than common oral squamous cell carcinoma with an increased incidence of regional lymph-node metastases and distant metastases. Our finding of a Ki-67 index of 30% and the immunohistochemical demonstration of p53 protein speaks well for enhanced aggressive biological behavior. The differential diagnosis includes the adenoid cystic, mucoepidermoid, neuroendocrine, adenosquamous and conventional oral squamous cell carcinoma. Because of early dissemination, radical surgical treatment and additional radiation therapy are considered necessary. Our findings indicate that partial clinical and histological tumor regression occurs after systemic neoadjuvant chemotherapy.

Biomarkers, Tumor↗
PubMed1997

[Soft tissue injuries, burns and scars].

The principles of diagnosis and therapy of soft tissue injuries, burns and scars that have been established in the course of many years' experience of facial and plastic surgery are expounded. The goal of early definitive management cannot always be achieved, particularly in the case of burns. Possible consequences are outlined. Recommendations are given, based on analysis of the authors' own case material and taking recent developments into account.

Adult↗
PubMed1996

Neurogenic lesions after posterolateral thoracotomy in young children.

In follow-up examinations of young patients we often noticed upward displacement of the left shoulder in cases where left-sided posterolateral thoracotomy had been carried out. Finding little discussion of this side-effect in the literature, we undertook the present study. The shoulder girdle of 69 patients who had undergone surgery for coarctation of the aorta between 1964 and 1984 was carefully examined to assess displacements and dysfunctions. In addition, in 24 of the patients electrodiagnostic examination was carried out of the associated muscles and nerves which were affected by the operation. We found disturbances of the muscular apparatus of the shoulder girdle in 80% of the cases: upward displacement of the shoulder (55%), downward displacement of the shoulder (8.7%), deviation of the scapula at rest (72.5%) and maximal elevated arms (40.6%), scapula alata (56.5%), and alterations of the posterior axillary line (39.1%). When considering only the cases of distinct upward or downward displacement of the shoulder, at least 25% of the operated children were affected. Children operated early (surgery during the first year of life) had more distinct alterations (47.6%) than those with later surgery (14.6%). Electromyographic examinations indicate that mainly disorders of the peripheral nerves caused by the operation led to these alterations of the shoulder girdle musculature. Although, except for one patient, no functional disorders were found, there were several cases in which the alteration caused quite severe cosmetic problems. One should pay more attention to positioning for surgery and do careful preparation to reduce these sequelae.

Age Factors↗
PubMed1996

Reducing post critical care infection.

Infection is a significant concern for seriously ill patients transferred to medical or surgical units following critical care. Understanding the factors that contribute to pulmonary, urinary, wound, and vascular access infections enables nurses to effectively intervene to lessen this risk. Key elements in reducing susceptibility are discussed.

Causality↗