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Biomedical subjects

E Kastenbauer

Publications and source records attributed to E Kastenbauer.

At least 37 records · Page 2Linked to original sources
PubMed1997

Enhanced epithelial proliferation due to elevated levels of interleukin-1 receptors in middle ear cholesteatomas.

Middle ear cholesteatoma epithelium is a rich source of interleukin-1-alpha (IL-1-alpha), being involved in both keratinocyte hyperproliferation and bone destruction. IL-1-alpha exerts its effects by binding to two distinct IL-1 receptors (IL-1-R). In this study, we have examined the expression of IL-1-R type II (IL-1-R-II) in cholesteatoma samples and have quantified these levels with computer-assisted image analysis. Normal aural skin was used as control. Immunostaining demonstrated the presence of IL-1-R-II in both epidermis and cholesteatoma keratinocytes. The receptors were 3 times higher than those in normal epidermis. The presence of IL-1-alpha in cholesteatoma epithelium coupled with the induced expression of IL-1-R-II indicates the existence of a highly regulated system of autocrine stimulation of cholesteatoma keratinocytes by IL-1.

Cell Division↗
PubMed1997

[Proliferative potential of nasal septum chondrocytes for in vitro culture of cartilage transplants].

BACKGROUND: Recent developments in the field of tissue engineering provide novel approaches in tissue repair and reconstructive surgery using the patients own cells. Isolated chondrocytes form new cartilage when seeded in appropriate scaffolds. Usually the number of cells from a cartilage biopsy is not sufficient. The present study investigates the potential of cell amplification of human nasal chondrocytes in monolayer culture. METHODS: Nasal cartilage cells from seven healthy patients with age between 16 and 60 years were enzymatically isolated with collagenase and hyaluronidase. Subsequently, cells were seeded in 75 cm2 culture flasks. After confluency, cultures were trypsinized, counted, and again seeded at a concentration of 5 x 10(4) cells/ml. Dulbecco's MEM supplemented with 10% FCS was used as culture medium. RESULTS: After enzymatic digest, an average of 5 x 10(5) cells per patient were isolated. At least 85% of the cells were vital. Within four to eight weeks, the cells number was increased 10(3) to 10(5) fold. No correlation between the proliferative activity and the age of the patient was observed in this study. DISCUSSION: The observed increase in cell number resembles about 10 to 20 cell doublings. Although the doubling time appears to be longer during the second month, no definite limit of proliferative activity was seen during the time of study. Proliferating chondrocytes in monolayer lose their tissue-specific phenotype. For the de novo formation of cartilage transplants, redifferentiation of the expanded cells has to be stimulated. CONCLUSION: This study shows that human nasal chondrocytes can be expanded sufficiently in monolayer for the engineering of autologous cartilage transplants.

Adolescent↗
PubMed1997

[Transplantation of in vitro cultured cartilage materials: characterization of matrix synthesis].

BACKGROUND: Recently a three-dimensional model for the formation of cartilage in vitro was developed. The aim of this study was to investigate the amount and quality of newly synthesized matrix after graftig in vitro engineered cartilage into athymic nude mice. MATERIAL AND METHODS: Group I received transplants consisting of human chondrocytes, agarose, and E 200 (a bioabsorbable polymer fleece that offers mechanical stability. Ethicon Inc). Group II received chondrocytes and agarose only. At intervals of six, 12, and 24 weeks after subcutaneous transplantation we used azan blue staining and antibodies against collagen type I, collagen type II, and chondroitin-4sulfate to characterize the matrix synthesis. A quantitative analysis was performed using the computer image analyzing software photoshop (Adobe Inc). RESULTS: In group I, the amounts of newly synthesized cartilage specific collagen type II and chondroitin-4 sulfate increased progressively. Twenty-four weeks after transplantation, these amounts were comparable to the original human cartilage from which the chondrocytes were derived. Collagen type I was detected only in small quantities in the periphery of the transplants. Gross examination revealed sufficient mechanical stability and unremarkable changes in size and form. In contrast to this, group II transplants showed markedly smaller amounts of cartilage specific matrix components as collagen type II and chondroitin-4 sulfate and at the same time greater amounts of collagen type I. It was found both in the periphery and in central parts of the transplants. There was a remarkable loss of volume in all transplants and mechanical stability was poor. CONCLUSIONS: The absorbable cell carrier E 200 not only offers mechanical stability to in vitro engineered cartilage but also had a positive effect on the development of cartilage in our experiments. In conclusion, in vitro engineered cartilage is a promising pathway for the replacement of cartilage defects.

Adolescent↗
PubMed1996

Resorbable polyesters in cartilage engineering: affinity and biocompatibility of polymer fiber structures to chondrocytes.

The resorbable polymers polyglycolic acid (PGA) and polylactic acid (PLA) are gaining increasing importance in tissue engineering and cell transplantation. The present investigation was focused on the biocompatibility and cell retaining behavior of PGA/poly-L-lactide (PLLA) (90/10) and PLLA nonwoven structures for the in vitro development of chondrocyte-polymer constructs. The effect of the relevant monomers to chondrocytes was analyzed. Type II collagen and poly-L-lysine were compared to improve loading of PGA/PLLA and PLLA polymer nonwovens with chondrocytes. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zoliumbrom ide (MTT) test was applied for quantification. At concentrations above 2 mg/mL, glycolic acid was more cytotoxic than lactic acid. As shown by pH equilibration, the cytotoxic effect is not due merely to the acidity of the alpha-hydroxy acids. Regarding the degradation products, glycolic acid, and L(+) lactic acid, nonwovens of PLLA are more biocompatible with chondrocytes than nonwovens of polyglycolide. Collagen type II and poly-L-lysine generally improved cell seeding on resorbable polymers in tissue engineering; however, their efficiency varies depending on the type of fiber structure.

Adult↗
PubMed1996

Interleukin 1 (IL-1) and IL-1-receptor antagonist (IL-1-RA) in middle ear cholesteatoma: an analysis of protein production and biological activity.

Cytokine networks are now presumed to play an essential role in the pathogenesis of middle ear cholesteatoma. Of the factors identified in cholesteatoma, interleukin-I (IL-1)-alpha appears to be especially important because of its stimulation of keratinocyte proliferation as well induction of bone resorption. To further characterize the possible role of IL-1 in the pathogenesis of cholesteatoma, we quantified the levels of IL-1 and IL-1-receptor antagonist (IL-1-RA) present using the bicinchonic acid protein assay and enzyme-linked immunosorbent assay (ELISA) on tissue extracts from 20 cholesteatoma specimens. The presence of biologically active IL-1 was also analyzed, using the cell line LBRM-33 and an ELISA for the detection of interleukin-2 (IL-2). Human skin obtained from the external ear canal was used as control. The amounts of IL-1-alpha in cholesteatoma (34.9 +/- 19.5) were higher than in human skin (6.7 +/- 2.8). The observed differences were statistically significant by Student's t-test (P < 0.01). Skin samples showed elevated concentrations of IL-1-RA (248.3 +/- 30.2) in comparison to that in the cholesteatoma (80.8 +/- 13.5). This was also statistically significant (P < 0.01). Whereas IL-1 activity was not detected in skin samples, all cholesteatoma specimens studied showed a stimulation effect on the production of IL-2 when incubated with the cell line LBRM-33. The results point to an over-expression of IL-1 concurrent with a decreased secretion of IL-1-RA in middle ear cholesteatoma. Furthermore IL-1-RA production is deficient relative to total IL-1 production, resulting in the presence of active IL-1.

Biological Assay↗
PubMed1996

Immunohistochemical detection of proliferating cell nuclear antigen in middle ear cholesteatoma.

Cholesteatoma epithelium is characterized by a keratinocyte dysregulation accompanied by destruction of the ossicles and temporal bone. Immunohistochemical methods using antibodies to cell-cycle-related antigens can be used as a means for assessing various aspects of proliferation in cholesteatoma tissue. They also have the important advantage of preserving the spatial orientation of proliferating cells in histological sections. Proliferating cell nuclear antigen (PCNA) is a 36 kDa DNA-delta-polymerase-associated protein that is directly involved in the mechanisms of DNA synthesis. In the present study the expression of PCNA was investigated in formalin-fixed, paraffin-embedded biopsy specimens of cholesteatomas and normal skin. Normal skin revealed nuclear staining in a small number of keratinocytes (PCNA grade, 1.5) located in the basal cell layer. In contrast, an increased number of PCNA-labeled basal and suprabasal epidermal cells (PCNA grade, 9.3) were found in cholesteatoma samples. Our findings indicate that PCNA represents a reliable marker for epithelial proliferation, showing that cholesteatoma epithelium proliferates at a higher rate than normal epidermis. These findings also support the concept of keratinocyte dysregulation in middle ear cholesteatoma.

Cell Division↗
PubMed1996

Effect of growth factors on matrix synthesis by human nasal chondrocytes cultured in monolayer and in agar.

Reconstructive surgery of multiple areas of the body may require replacement bone or cartilage transplants to repair defects or lesions of skeletal tissue. Advances in cell and tissue culture techniques now permit synthesis of autologous human cartilage in vitro. Several growth factors regulate the metabolism and activation of cartilage cells. To enhance culture conditions and effectiveness for in vitro cartilage engineering, the aim of our investigations was to characterize the influence of transforming growth factor (TGF)-beta and basic fibroblast growth factor (bFGF) on human nasal septal chondrocytes. The isolated cells were cultured as monolayers on plastic and in soft agar. The biological effects of the growth factors were assessed by determining synthesis of total protein and proteoglycan. TGF-beta caused a dose-dependent stimulation of total protein as well as glycosaminoglycan synthesis by all chondrocytes cultured. This stimulatory effect of TGF-beta was greater for chondrocytes cultured in soft agar than for chondrocytes cultured on plastic. No stimulatory effects of matrix synthesis was observed for bFGF in either culture condition. Our results show that TGF-beta can be employed to enhance in vitro production of cartilage grafts for reconstructive surgery.

Cartilage↗
PubMed1996

Role of interleukin 6 in epithelial hyperproliferation and bone resorption in middle ear cholesteatomas.

Locally produced pro-inflammatory cytokines are considered to play an important role in the initiation and/or maintenance of inflammatory diseases. In cholesteatomatous lesions there are increased levels of some cytokines and inflammatory mediators like interleukin 1, tumor necrosis factor and colony-stimulating factor, etc. Interleukin 6 (IL-6) can be produced by different cells present in cholesteatoma (e.g. keratinocytes, lymphocytes, fibroblasts and macrophages). Until now, no data have been available on the role of IL-6 in cholesteatoma. In this study we used immunohistochemistry to investigate the presence and distribution of IL-6 in tissue samples from cholesteatoma patients. Levels of the cytokine were quantified in tissue extracts using an enzyme-linked immunosorbent assay. Finally, the presence of biologically active IL-6 was analyzed in the murine cell line 7TD1. Human skin samples obtained from the external ear canal were used as controls. Using the anti-IL-6 antibody in an alkaline phosphatase anti alkaline phosphatase technique, a moderate diffuse staining of the whole epidermis was observed in sections of normal skin. In cryostat sections of cholesteatoma samples, a stronger staining of the whole epithelium was observed. Many of the cells infiltrating the cholesteatoma stroma also showed positive immunostainings. The concentration of IL-6 in relation to the total protein concentration in cholesteatoma (119.33 +/- 30) were higher than in human skin (9.16 +/- 13). While IL-6 activity was not detected in skin samples, two of the ten cholesteatoma samples studied showed a stimulatory effect when incubated with the cell line 7TD1. The overexpression of IL-6 in middle ear cholesteatoma suggests a participation of this cytokine in some of the clinical features seen: epithelial hyperproliferation and bone resorption. The absence of biological activity in the majority of the cholesteatoma samples points to the presence of natural inhibitors for IL-6.

Bone Resorption↗
PubMed1996

Monoclonal antibodies against human chondrocytes.

Cell-specific antigens are mainly found in cells or membrane surfaces rather than in the surrounding matrix. However, until now it was not possible to produce antibodies specific for cellular structures of chondrocytes. In 1989, Lance (Immunol. Lett. 21:63-73; 1989) first established specific monoclonal antibodies for human articular chondrocytes tested only by immunofluorescence. Studies describing the specificity of these five antibodies (HUMC 1-5) and their relevance for immunohistological analysis of cartilage tissue were not available until now. Therefore, the aim of the following study was to investigate the distribution of HUMC 1, 2, 3, 4, and 5 in mesenchymal cells in vivo and in vitro immunohistochemically. Further investigations concentrate on the localization of chondrocyte specific antigens using immunoelectron microscopy. Immunohistological studies showed positive immunostainings with all five antibodies in human chondrocytes in vivo and in vitro. A cross-reaction with human fibroblasts and osteoblasts for the antibodies HUMC 2 and HUMC 5 was observed. Furthermore, a parallel loss of immunoreactivity for HUMC 1, HUMC 3, and HUMC 4 was observed in cultured chondrocytes indicating that the specific antigens vanish during differentiation observed in vitro. Subsequent immunoblot analysis employing collagens as antigens did not show any reactivity. Using immunoelectron microscopy, gold particle labeling was observed in intracytoplasmatic vesicles of isolated chondrocytes. Our results indicate that HUMC 1, HUMC 3, and HUMC 4 are specific for cartilage cells and might be suitable for immunohistological analysis of different cartilage tissues and pathologically altered chondrocytes.

Antibodies, Monoclonal↗
PubMed1996

[Functional MRI of the pharynx in obstructive sleep apnea using rapid 2D FLASH sequences].

Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager ("Vision", Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of 6 images/s and an in-plane resolution of 2.67 x 1.8 mm were achieved. The mobility of the tongue, soft palate and pharyngeal surface could be clearly delineated. The MRI findings correlated well with the clinical examinations. We propose ultrafast MRI as a reliable and non-invasive method of evaluating pharyngeal obstruction and their levels.

Adult↗
PubMed1996

[High concentrate A-mulsin, a new therapy concept in laryngeal leukoplakia].

BACKGROUND: Leukoplakia, a white patch in the oral cavity or in the larynx that cannot be scraped off is a premalignant precursor of squamous cell carcinoma. It is tobacco-related and easily monitored. The rate of transformation of leukoplakia into invasive cancer is directly related to the degree of histologic abnormality. In the largest and longest study in the United States (mean follow-up, 7.2 years), the long-term transformation rate for dysplastic lesions was 36%. Surgical removal is considered the best therapy. However many patients operated on for oral leukoplakia later develop local relapses, new leukoplakias, or squamous cell carcinoma. Although leukoplakia lesions can show spontaneous regression, the response rate observed under treatment of retinoids is much greater. METHODS: In our study, high-dose retinyl palmitate was used for the first time on leukoplakias of the larynx. The study was conducted in two phases. In the first phase, all patients underwent induction therapy with a high dose of Retinyl Palmitate (A-Mulsin Hochkonzentrat, Mucos Pharma, Geretsried, Germany) 300.000 IU daily for the first week up to 1,500,000 IU daily in the fifth week. Patients whose lesions progressed during this period were withdrawn from the study. In the second phase, patients whose lesions responded to treatment or remained stable were then assigned to a maintenance therapy. The median duration of treatment was 104 days (range 15-272). RESULTS: We observed a complete remission rate of 65% (20 out of 31 patients), a partial remission in 8 patients (26%) and a relaps in three patients (9%) during the next 15 months follow-up. Relapses were mainly seen in patients with a history of a carcinoma in situ or squamous cell carcinoma. CONCLUSIONS: One of the main reasons for using retinyl palmitate in patients with larynx leukoplakia was to avoid general anesthesia in elderly patients who were considered as high risk patients for undergoing surgery. These results indicate that retinyl palmitate has substantial activity in larynx premalignancy. Because of its minor toxicity, it is an excellent candidate for a preventive agent for larynx cancer.

Aged↗
PubMed1996

[Intra-arterial cisplatin and sequential radiotherapy. Long-term follow-up].

BACKGROUND: The objective of this study was to improve the results of irradiation by prior application of intraarterial (i.a.) chemotherapy with cisplatin. METHODS: Sixty-three patients suffering from advanced head and neck cancer without previous treatment were prepared for intraarterial chemotherapy by neck dissection without resection of the primary tumor and by modification of the carotid artery by creating a more inferiorly positioned bifurcation to facilitate intermittent i.a. infusion. The patients received approximately 400 mg cisplatin over a period of four to five weeks followed by irradiation with 60Co (64 Gy HD). RESULTS: The survival rate at five years in all patients with adequate i.a. chemotherapy was 19 of 49 (39%), except those with adenoid-cystic carcinoma, who had a five-year-survival rate of 100%. CONCLUSION: The results indicate that inductive i.a. chemotherapy with cisplatin has a positive influence on the outcome of irradiation even in inoperable head and neck cancer, which is defined by a longer period of remission with the possibility of curing the disease.

Antineoplastic Agents↗
PubMed1996

[Somatic gene therapy in squamous epithelial carcinomas of the head-neck area].

Gene therapy is an important new approach to the treatment and prevention of human diseases. Somatic gene therapy involves the introduction of novel genetic material into somatic cells to express therapeutic gene products. Two main strategies in somatic gene therapy of cancer are applied: the genetic correction of the defect, or the elimination of cancer cells by cytotoxic drugs or the immuno system. Gene transfer can be accomplished by physical and chemical methods or nonreplicating viruses. The different transfer systems vary strongly in their efficiency of transfection, plasmid maintenance, and protein expression. The clinical application could be performed in two ways: Firstly, by in vivo application of genome modifying substances injected directly into the tumour; secondly, by ex vivo application of genetically modified tumour cells as a tumour vaccine. The following review will discuss some of the gene therapy strategies that could be effective in managing head and neck cancer.

Carcinoma, Squamous Cell↗
PubMed1996

MRI-guided laser interstitial thermal therapy (LITT) of head and neck tumors: progress with a new method.

A less invasive method for treatment of tumors is being tested based on interstitial photothermal ablation via infrared Nd:YAG laser fiber optics. The technique can be applied safely and effectively for therapy of common tumors in humans. In the current study five patients were treated by interstitial laser palliation with the Nd:YAG laser using special fiberoptic applicator tips, which distribute laser energy efficiently throughout the tumor volume. Magnetic resonance imaging (MRI) scanning was employed to locate the tumor, position the fibers correctly, and monitor the development of thermal necrosis in the tumors. Two patients were diagnosed with adenoid cystic carcinoma of the paranasal sinuses, one with a recurrent carcinoma of the tongue and oropharynx, one with a recurrent carcinoma limited to the oropharynx, and one patient with a carcinoma of the epi- and oropharynx. The maximum follow-up without recurrence was 2 years in a patient with an adenoid cystic carcinoma tumor of the paranasal sinuses. There were no immediate or delayed complications. Anatomical structures including eyes, brain, and important vessels were recognized by MRI during laser therapy. MRI-guided interstitial laser photothermal ablation appears to be a safe and effective method for treatment of selected tumors of the head and neck region with particular applications in palliation of inoperable tumor recurrences.

Aged↗
PubMed1996

Quantitative analysis of interleukin-1-alpha gene expression in middle ear cholesteatoma.

Regardless of its origin, cholesteatoma is characterized by the presence of a keratinizing epithelium with an hyperproliferative behavior leading to a very important bone resorption. Previous studies have demonstrated overexpression of interleukin-1 (IL-1 protein in middle ear cholesteatoma by immunohistochemistry and enzyme-linked immunosorbent assay, suggesting a significant role for IL-1-alpha. In this study, the presence of IL-1-alpha messenger ribonucleic acid (mRNA) was quantified by in situ hybridization on frozen sections (n = 10) and by computer-assisted image analysis. Human skin obtained from the external ear canal (n = 10) was used as the control. A higher percentage of cells hybridized for the antisense probes IL-1-alpha mRNA was found in cholesteatoma epithelium. Furthermore, keratinocytes of the suprabasal cell layers were also found to contain specific hybridizations. Some cells in cholesteatoma stroma also contained IL-1-alpha mRNA transcripts. The results of this study confirm the central role of IL-1-alpha in the epithelium hyperproliferation and bone resorption observed in middle ear cholesteatoma.

Cholesteatoma, Middle Ear↗
PubMed1996

Basic innervation pattern and distribution of classic autonomic neurotransmitters in human nasal mucosal vasculature.

The neural control of human nasal vasculature is still not completely understood. This study was performed to demonstrate the innervation pattern of the different vessel types and to distinguish between nor-adrenergic and cholinergic structures. General innervation was demonstrated using antibodies to neuron-specific enolase and S-100 protein. Autonomic structures were shown by using antibodies to tyrosine hydroxylase and choline acetyltransferase (ChAT). In addition, choline acetyltransferase (AChe) histochemistry was performed. Nasal vasculature is controlled by a dense innervation that increases with the thickness of the tunica media. While all larger vessels show a mixed autonomic innervation, sympathetic structures seem to predominate in veins. These findings demonstrate that classic neurotransmitters play a major role in the regulation of nasal vasculature. The stronger innervation of arteries and cushion veins underlines their central position in the control of nasal air flow.

Adrenergic Fibers↗
PubMed1996

Influence of chemical allograft preservation procedures on the human immunodeficiency virus.

Since chemically preserved allogenic transplants have an established place in reconstructive procedures, the possibility of transferring the human immunodeficiency virus (HIV) with these transplants has been intensively discussed. In this study the authors obtained brain and spleen samples from six HIV-infected cadavers and preserved them with Merthiolate, Cialit, and formaldehyde. After preservation, the tissues were examined for proviral HIV-1 DNA (gag, pol, env) using the polymerase chain reaction. Proviral sequences were clearly demonstrated after the preservation procedure. The results of this study indicate that HIV remains in tissues that have been treated with Merthiolate, formaldehyde, or Cialit. Further investigations are necessary to determine if the virus is in an inactivated or activated form. It can be concluded that, because of the possible transmission of HIV by chemically preserved homografts, serologic screening of donors should be mandatory.

Base Sequence↗