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Biomedical subjects

A Naumann

Publications and source records attributed to A Naumann.

At least 19 recordsLinked to original sources
PubMed2006

Cognitive deficits in narcolepsy.

The aim of the investigations was to explore the nature and the severity of cognitive deficits in narcolepsy patients. In two studies, narcolepsy patients were compared with matched control subjects on a range of attention, memory and executive control tasks. Impairments were only observed on attention and executive function tasks which involved higher demands on inhibition or task management abilities whereas relatively routine memory and attention tasks yielded intact performance in narcolepsy patients. The overall pattern of results indicates an executive control deficit in narcolepsy which might be related to a reduction of available cognitive processing resources because of the need for continuous allocation of resources to monitoring and maintenance of vigilance.

Arousal↗
PubMed2005

[Plastic surgery to correct deformities of the ear].

For the plastic-surgical correction of mild deformities of the ears, well-proven incisional and suturing techniques are available. Only in exceptional cases is skin grafting or the use of cartilage ersatz material required. In the plastic surgical treatment of moderate to severe ear deformities, in contrast, not only incisional and suturing techniques, but also free skin grafts and ersatz materials are needed. At the ENT Department of the Ludwig-Maximilian University in Munich, plastic reconstruction of moderate to severe deformities of the external ear using porous polyethylene implants instead of rib cartilage grafts has been practiced with success for the past two years or so. Porous polyethylene implants provide good results and may help to avoid pre- and postoperative morbidity at donor site defects.

Cartilage↗
PubMed2005

[Niikawa-Kuroki syndrome. Which characteristics must the HNO doctor consider in its diagnosis].

Niikawa-Kuroki syndrome (Kabuki make-up syndrome) is a congenital disorder with characteristic facial features and possibly anomalies of the skeletal system and internal organs. There is an increasing number of reports of patients with combined hearing impairment, inner ear deformities or sensorineural hearing impairment. In addition, the patients often suffer from therapy-resistant chronic otitis media. In addition to multiple cardiac and renal deformities, our 3 year old patient has a hearing impairment due to chronic otitis media with chronic otorrhea, and requires a hearing aid. A high-definition CT scan of the petrosal bone revealed, for the first time in a patient with Niikawa-Kuroki syndrome, a large vestibular aqueduct syndrome and deformities of the vestibular system. We examine the problems involved with treating chronic otorrhea in chronic otitis media and providing patients with BTE hearing aids.

Abnormalities, Multiple↗
PubMed2004

[Synovial sarcoma of the hypopharynx - two case reports].

BACKGROUND: Synovial sarcoma is a rare soft tissue malignancy that most often occurs in the extremities of young adults. Approximately 3 % of these mesenchymal malignant tumors occur in the head and neck region. Up to now about 100 cases have been published. PATIENTS: We report on two cases of a synovial sarcoma of the hypopharynx. In the first case the patient died 3.5 years after beginning of therapy including all therapeutical efforts (surgery, chemotherapy, radiotherapy). The second patient with a synovial sarcoma of his left hypopharynx and a distant metastasis in his 8th thoracic vertebral body is actually treated by neoadjuvant chemotherapy and included into a clinical study to optimize therapy of advanced soft tissue sarcomas. Further surgical treatment depends on the success of this therapeutic approach. CONCLUSION: Despite multitherapeutic approaches over all 5-year survival rates for advanced synovial sarcomas of the head and neck have moderately improved in the recent decades and an ideal treatment has not yet surfaced. Modification of accepted treatment modalities is discussed and therapy options in controlled clinical studies are described.

Adult↗
PubMed2003

[Chronic recurrent otitis externa. Excessive ear hygienic care can have sequelae].

Numerous factors may be involved in the development of chronic recurrent otitis externa: altered pH of the cerumen, increased susceptibility to contact allergens (e.g. nickel ear-rings) in atopic patients, the use of instruments for cleaning out the auditory canal, the presence of a foreign body, congential narowing of the auditory canal, or systemic diseases (in particular diabetes mellitus). For diagnostic purposes, the use of the otoscope is mandatory, and swabs to determine the presence of bacteria or fungi are to be recommended. Treatment is dictated by the clinical picture presenting, and may comprise the local application of antibiotic cortisone containing or antimycotic preparations and temponade of the auditory canal (acute inflammatory phase) or pH-stabilizing lotions (chronic dry inflammatory phase) with the aim of ameliorating the frequently highly troublesome pruritus.

Cerumen↗
PubMed2003

Clinical aspects and strategy for biomaterial engineering of an auricle based on three-dimensional stereolithography.

At the present time, the partial and/or complete reconstruction of an auricle from autologous rib cartilage is one of most widely published techniques. In the field of tissue engineering, different techniques have been described to generate cartilage tissue using isolated chondrocytes. The basis of these tissue-engineering techniques is bioresorbable or non-bioresorbable biomaterials, which serve as a three-dimensional cell carrier. Tissue engineering of an auricle requires preformed bioresorbable biomaterials designed to fit the form of a patient's auricular defect. Three-dimensional imaging acquired from computed tomography scans or laser surface scanning has become an important tool in modern medicine. This study represents the preoperative procedures for the reconstruction of an auricle through tissue engineering in accordance with the clinical aspects. Hyaff 11, a hyaluronic acid derivative, was used as a three-dimensional cell carrier for isolated human nasoseptal chondrocytes. The chondrocytes were amplified in a conventional monolayer culture before the cells were seeded on a hyaluronic non-woven mesh and cultured in vitro for 4 weeks. The chondrogenic potential of human nasal chondrocytes in Hyaff 11 was investigated by confocal laser scanning microscopy, histology (toluidine blue) and immunohistochemistry (collagen type II). Computer-aided design (CAD) and manufacture of an auricle model with stereolithographical methods were used for the prefabrication of a bioresorbable three-dimensional cell carrier designed in the form of a patient's auricular defect. The cell carrier used was Hyaff 11, a fully benzyl-esterified hyaluronic acid derivative. Confocal laser scanning microscopy has shown good cell attachment, a homogenous distribution of amplified chondrocytes and a viability of more than 90%. After 4 weeks in vitro culture the human nasoseptal chondrocytes synthesized new cartilage with the expression of cartilage-specific collagen type II. In order to shape a patient's designed scaffold the auricle model was fitted exactly and symetrically to the contralateral side. Subsequently, the mirror image patient-specific model was used to prepare an identical scaffold model made of a fully benzyl-esterified hyaluronic acid derivative. The bioresorbable scaffold that was produced gave a satisfactory representation of auricle structure. Bioresorbable preformed biomaterials in the form of a patient's auricle defect represent an important prerequisite for the tissue engineering of autologous auricle grafts. Hyaff 11 seems to be a promising material for tissue engineering of cartilage transplants, and the application of this approach will improve conventional reconstructive surgery in the future.

Absorbable Implants↗
PubMed2003

[Quality of life of children and adolescents with psychiatric disorders. Results of the 1st multicenter study with an inventory to assess the quality of life in children and adolescents].

OBJECTIVE: A newly developed, disorder-nonspecific instrument to measure the quality of life in children and adolescents (ILK, Mattejat et al., 1998) was tested with regard to its ability to differentiate between psychiatric in- and outpatient samples. METHODS: 626 children and adolescents from regionally different in- and outpatient clinics completed the ILK questionnaire. The data obtained were first described and then analyzed by means of logistic regression analysis. RESULTS: Whereas the descriptive analysis revealed that inpatients evaluated all areas of life more unfavorably than outpatients did, the logistic regression analysis modified these results. It became evident that some of the findings obtained were due to the effects of age and/or gender. However, given age and gender as covariates, there still remained some important life domains in which inpatients were more impaired than outpatients. CONCLUSIONS: The ILK turned out to be an efficient and economic instrument to measure the quality of life in children and adolescents depending on the severity of their disorder. Moreover, it is sensitive to effects of age and gender. As the ILK is able to reliably identify areas with a reduced quality of life, it offers valuable starting points for indications, therapy planning and initial therapeutic interventions.

Activities of Daily Living↗
PubMed2002

Molecular characterization of breast cancer cell lines by expression profiling.

PURPOSE: Gene expression patterns provide detailed insights into cellular regulation that reflect minor differences of cellular capacity not accessible by standard descriptions of the cellular phenotype or origin. METHODS: To identify fundamental differences and similarities we analyzed the gene expression patterns of four breast cancer cell lines: MCF-7, SK-BR-3, T-47D, and BT-474. RESULTS: Although only a small subset of genes (597) is represented on the Atlas-cDNA-Array (Clontech) used, clear differences in the expression of a number of genes could be detected. For example, unique high levels of expressions were found for the HLH-protein ID-1 (MCF-7) and the receptor tyrosine kinase erbB2 (SK-BR-3 and T-47D). Most genes analyzed were expressed at comparable levels in all cell lines studied. CONCLUSIONS: For interpretation of the results sets of genes that show similar variation of expression among the cells were grouped together. Furthermore, our analysis allows the assignment of similarity values that lead to a relation profile of the cell lines. How these results correlate with known biological properties of the cell lines is discussed. Additionally, we demonstrate that results obtained by cDNA-Array hybridization for expression of the ErbB receptor family correlate well with competitive RT-PCR, thus confirming the reliability of the cDNA-Array analysis.

Breast Neoplasms↗
PubMed2002

[Mesenchymal stem cells--a new pathway for tissue engineering in reconstructive surgery].

INTRODUCTION: Mesenchymal stem cells (MSC) have the capacity to differentiate into chondrocytes with the synthesis of cartilage. This report presents the use of human adult bone marrow derived mesenchymal stem cells for tissue engineering of autologous cartilage grafts. METHODS: Human bone marrow aspirates were obtained from the iliac crest and fractionated on a Percoll gradient. The isolated hMSC were plated at 20 x 10 (6) cells per 100 mm (2) culture dish. After 21 days in culture at 37 degrees C with 5 % CO 2, the adherent multiplied MSC were trypsinized, counted, and tested for viability by trypan blue assay. The hMSCs were loaded into a sterile 15 ml polypropylene tube (0.5 Mio cells/ml) and centrifuged on the bottom of the tube at 500 g for 5 minutes. The MSC were cultivated for 3 weeks in vitro in a specific chondrogenetic medium composed of Dulbecco's Modified Eagles Medium-High Glucose supplemented with 10 ng/ml transforming growth factor-beta 1, 1 % ITS-Premix medium, 80 micro M ascorbic acid, and 100 nM dexamethasone. RESULTS: Histological and immunohistochemical studies performed after 3 weeks in three dimensional culture demonstrated the expression of cartilage specific collagen type II and X as well as proteoglycans. CONCLUSION: Human adult mesenchymal stem cells derived from bone marrow aspirates have the ability to differentiate into chondrocytes under specific culture conditions by growth factors. The use of adult mesenchymal stem cells may be a promising tool for tissue engineering of autologous cartilage grafts in reconstructive surgery in the future.

Adult↗
PubMed2001

Attentive and preattentive processing in narcolepsy as revealed by event-related potentials (ERPs).

Narcolepsy is a neurological disorder, characterised by excessive daytime sleepiness, sleep attacks, cataplexy and abnormal manifestations of rapid eye movement sleep. Recent studies suggest that neuropsychological impairments in narcolepsy may include memory and attention deficits due to a monoaminergic or cholinergic transmitter dysfunction. To explore the nature of cognitive problems, the P300 and mismatch negativity (MMN) event-related potentials were investigated in narcoleptic patients and matched controls. Narcoleptics showed significantly increased P300 amplitudes relative to controls, especially at frontal recording sites. While control subjects exhibited typically larger MMN over the right than the left hemisphere, in particular at frontal and central electrodes, narcoleptics did not show this asymmetry. These results are interpreted as possible alterations in cognitive preattentive and attentive processing associated with altered functioning of the prefrontal cortex in narcolepsy.

Acoustic Stimulation↗
PubMed2001

[Detection of humoral immune response to inner ear proteins in patients with sensorineural hearing loss].

BACKGROUND: The precise mechanism of inner ear disease is still unknown. An autoimmune reaction could be one of several possible pathogenic factors involved in progressive sensorineural hearing loss. Heat shock protein 70 is suggested to play an important role in the development of autoimmune diseases. The aim of this study is the investigation of humoral immune reactivity to inner ear components in patients with sensorineural hearing loss. METHODS: The presence of antibodies to inner ear components was determined by immuno-blotting extracted bovine or human inner ear proteins. Study groups consisted of patients with idiopathic progressive sensorineural hearing loss (group A), patients with Menière's disease (group B), patients with sudden hearing loss (group C), patients with otosclerosis (group D), patients with Cogan's disease (group E), and individuals without hearing problems (group F). RESULTS: 40% of the patients with progressive sensorineural hearing loss showed reactivity against a 68-kDa protein extracted from bovine inner ear. In contrast to this, only 5% of healthy individuals and 10% with Menière's disease showed reactivity against the 68-kDa protein from bovine inner ear or against bovine heat shock protein 70. Some of the patients who showed reactivity against bovine inner ear proteins were tested with human inner ear and human heat shock protein 70; all of these showed reactivity. Approximately 6% of the patients with sudden hearing loss (group C), otosclerosis (group D), and Cogan's disease (group E) showed reactivity to inner ear proteins. A non-specific humoral immune reaction against inner ear proteins with molecular weights of 30, 40, 50, 60, and 220 kDa was observed in all patients. DISCUSSION: These results indicate a humoral immune reactivity against heat shock protein 70, which might be responsible for the pathogenesis of progressive sensorineural hearing loss.

Adult↗
PubMed2001

Contamination of bronchoscopes with Mycobacterium tuberculosis and successful sterilization by low-temperature hydrogen peroxide plasma sterilization.

BACKGROUND: The transmission of mycobacteria by bronchoscopes has been reported several times in the last years. To explore methods to prevent transmission of tuberculosis in this way, we sterilized contaminated bronchoscopes with low-temperature hydrogen peroxide gas plasma sterilization. METHODS: Bronchoscopes were contaminated with Mycobacterium tuberculosis and decontaminated with a washer/disinfector ("normal washing"). Some were additionally disinfected with glutaraldehyde ("intensive washing"). Afterward the bronchoscopes were sterilized by low-temperature hydrogen peroxide plasma sterilization. RESULTS: After normal washing, 8/17 samples had positive results by culture, and 7/17 had positive results by nucleic acid amplification technique. After intensive washing, all samples had negative results by culture, and 10/25 had positive results by nucleic acid amplification technique; after sterilization with low-temperature hydrogen peroxide plasma sterilization, all samples had negative results by culture and nucleic acid amplification technique. CONCLUSION: Washing of bronchoscopes, as performed normally, is not sufficient for decontamination of bronchoscopes. Additional disinfection is recommended. If the nucleic acid amplification technique is used for diagnostic procedures, sterilization by low-temperature hydrogen peroxide plasma sterilization is recommended to avoid false-positive results.

Anti-Infective Agents, Local↗
PubMed2001

Long-term administration of the HMG-CoA reductase inhibitor lovastatin in two patients with cholesteryl ester storage disease.

OBJECTIVE: In order to suppress de novo cholesterol and VLDL biosynthesis, a long-term therapy trial with lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, was initiated in two patients with cholesteryl ester storage disease (CESD), and concentrations of plasma lipids were monitored over a period of 9 years. METHODS: We studied two male patients with enzymatically confirmed CESD in whom long-term lovastatin therapy (8 and 9 years) was begun at the age of 7 and 19 years. The diagnosis of CESD was confirmed by the measurement of human lysosomal acid lipase (hLAL) activity in cultured skin fibroblasts and leukocytes. Restriction fragment length polymorphism (RFLP) analysis revealed that both subjects are homozygotes for the common CESD splice site mutation. Levels of serum lipids and lipoproteins were measured yearly. RESULTS: During the first year, total serum cholesterol decreased from 317 to 201 mg/dl in Patient A and from 228 to 120 mg/dl in Patient B, due mainly to the reduction of low-density lipoprotein (LDL) cholesterol from 262 to 151 mg/dt in Patient A and from 166 to 66 mg/dl in Patient B. Accordingly, the LDL cholesterol : high density lipoprotein (HDL) cholesterol ratio was markedly reduced in both patients after one year of therapy. The treatment was continued and, after 9 years of further medication, low total cholesterol and LDL cholesterol levels were still maintained. CONCLUSIONS: The study demonstrates that HMG-CoA reductase inhibitors are well tolerated drugs during long-term treatment of CESD patients and may help to prevent the development of premature atherosclerosis.

Adult↗
PubMed2000

[Subcutaneous preservation of an amputated auricle. Morphological changes].

BACKGROUND: Microsurgical replantation of an avulsed auricle remains a challenge in reconstructive surgery. Secondary reconstruction of a traumatic lost auricle is usually performed using a costal cartilage framework according to well documented techniques or with a prosthesis. In order to minimize donor-site morbidity, various efforts can be undertaken to preserve the amputated auricle by implanting the de-epithelialized cartilage framework in a subcutaneous pocket on the surface of the mastoid. Where preservation is successful, this original cartilage could be used for reconstructive treatment. PATIENT AND RESULTS: This study describes the histologic and immunohistologic changes in a complete traumatic avulsion of the auricle with subsequent cartilage conservation for eight months within a skin pocket. Trauma, preparation and preservation were accompanied by morphologic changes that included generation of local ossification centers and infiltration of fibrous tissue. We compared the macroscopic and microscopic morphology of the amputated part to native elastic cartilage following maximal denutrition and temporary heterotopic implantation in conjunction with atypical tension and pressure properties of the retroauricular pocket. CONCLUSION: In this case, the limited success of cartilage conservation in the subcutaneous pocket required conventional auricle reconstruction with autologous costal cartilage.

Adult↗
PubMed1999

Regulation of UDP-N-acetylglucosamine:dolichyl-phosphate N-acetylglucosamine-1-phosphate transferase by retinoic acid in P19 cells.

UDP-N-acetylglucosamine:dolichyl-phosphate N-acetylglucosamine-1-phosphate transferase (GPT) is the first enzyme in the dolichol pathway of protein N-glycosylation, and is implicated in the developmental programmes of a variety of eukaryotes. In the present study we describe the effects of all-trans-retinoic acid (RA) on the levels of GPT protein and enzymic activity, and on the transcription rate of the GPT gene, in mouse P19 teratocarcinoma cells. RA caused a dose-dependent and protein-synthesis-dependent induction of enzyme activity. The maximum induction of GPT activity (about 3-fold) required 2 days of exposure to 1 microM RA. Induced GPT activity also resulted in an increase in the rate of incorporation of [3H]mannose into Glc3Man9GlcNAc2. Enzymic activities paralleled GPT gene expression. The GPT gene was induced (2-fold) after 7 h of RA treatment. An approx. 3-fold increase in a 48 kDa GPT protein and approx. 4-fold increases in the levels of three GPT transcripts (1.8, 2.0 and 2.2 kb) were observed after 2 days of RA treatment. The enhanced levels of GPT protein and mRNAs began to decline 3 days after the initiation of differentiation, and GPT expression was down-regulated during cellular differentiation. GPT activity decreased about 2. 8-fold to a constant level in differentiated P19 cells. The results indicate that the RA-induced enzyme activity was mainly determined by increased transcription of the GPT gene. RA-treated P19 cells were about 4-fold more resistant to tunicamycin, a fungal antibiotic which inhibits GPT, than were control cells. In addition, GPT activity in membranes from RA-treated P19 cells exhibited approx. 4-fold increased resistance to tunicamycin compared with activity in membranes from untreated control cells, demonstrating that resistance to tunicamycin is correlated with induced GPT activity. Furthermore, increased GPT activity had regulatory significance with regard to the rate of incorporation of [3H]mannose into Glc3Man9GlcNAc2-P-P-dolichol and into glycoproteins. Together, the data provide additional insights into the hormonal regulation of GPT and present evidence that the RA-mediated induction of GPT has a regulatory impact on the dolichol pathway.

Animals↗
PubMed1999

Evaluation of the middle and inner ear structures: comparison of hybrid rendering, virtual endoscopy and axial 2D source images.

Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment.

Adult↗
PubMed1998

Cartilage reconstruction in head and neck surgery: comparison of resorbable polymer scaffolds for tissue engineering of human septal cartilage.

New cell culture techniques raise the possibility of creating cartilage in vitro with the help of tissue engineering. In this study, we compared two resorbable nonwoven cell scaffolds, a polyglycolic acid/poly-L-lactic acid (PGA/PLLA) (90/10) copolymer (Ethisorb) and pure PLLA (V 7-2), with different degradation characteristics in their aptitude for cartilage reconstruction. Chondrocytes were isolated enzymatically from human septal cartilage. The single cells were resuspended in agarose and transferred into the polymer scaffolds to create mechanical stability and retain the chondrocyte-specific phenotype. The cell-polymer constructs were then kept in perfusion culture for 1 week prior to subcutaneous transplantation into thymusaplastic nude mice. After 6, 12, and 24 weeks, the specimens were explanted and analyzed histochemically on the presence of collagen (azan staining), proteoglycans (Alcian blue staining), and calcification areas (von Kossa staining). Furthermore, different collagen types (collagen type I, which is found in most tissues, but not in hyaline cartilage matrix; and collagen type II, which is cartilage specific) were differentiated immunohistochemically by the indirect immunoperoxidase technique. Vascular ingrowth was investigated by a factor VIII antibody, which is a endothelial marker. Quantification of several matrix components was performed using the software Photoshop. Significant differences were found between both nonwoven structures concerning matrix synthesis and matrix quality as well as vascular ingrowth. Ethisorb, with a degradation time of approximately 3 weeks in vitro, showed no significant differences from normal human septal cartilage in the amount of collagen types I and II 24 weeks after transplantation. Thin fibrous tissue layers containing blood vessels encapsulated the transplants. V 7-2 constructs, which did not show strong signs of degradation even 24 weeks after transplantation, contained remarkably smaller amounts of cartilage-specific matrix components. At the same time, there was vascular ingrowth even in central parts of the transplants. In conclusion, polymer scaffolds with a short degradation time are suitable materials for the development of cartilage matrix products, while longer stability seems to inhibit matrix synthesis. Thus, in vitro engineering of human cartilage can result in a cartilage-like tissue when appropriate nonwovens are used. Therefore, this method could be the ideal cartilage replacement method without the risk of infection and with the possibility of reconstructing large defects with different configurations.

Adult↗