Biomedical subjects

R Staudenmaier

Publications and source records attributed to R Staudenmaier.

At least 19 recordsLinked to original sources

PubMed2006

[Does nicotine add to the carcinogenic strain of tobacco smoke?].

BACKGROUND: It is accepted that nicotine in tobacco smoke causes addiction via nicotinic acetylcholine receptors in the central nervous system. For a long time, the tumorigenic potential of smoking was attributed to compounds other than nicotine. However, more recently data have accumulated which suggest that nicotine may add to the cancer risk by stimulating cellular growth via non-neuronal acetylcholine receptors, by suppressing apoptosis, and by inducing angiogenesis not only in atheromatous plaques but also in tumors. In the present study the possible direct genotoxic effects of nicotine on DNA were investigated in human target cells of carcinogenesis in the upper aerodigestive tract. PATIENTS AND METHODS: Human nasal mucosa, lymphatic tissue of the palatine tonsils, supraglottic epithelium of the larynx, and peripheral lymphocytes were exposed to rising concentrations of nicotine. DNA damage was investigated by alkaline single-cell microgel electrophoresis (Comet) assay. Cytotoxicity was assessed by trypan blue exclusion. RESULTS: Nicotine induced dose-dependent DNA damage in all cell types at low cytotoxic concentrations that allowed viabilities well above 80%. The lowest nicotine concentrations eliciting a significant increase in DNA migration were 1 mM for tonsillar cells and 0.25 mM for all other cell types. CONCLUSION: Nicotine induces genotoxic effects in human target cells of carcinogenesis in the upper aerodigestive tract at relevant concentrations. Thus, nicotine may contribute directly to tumor initiation resulting from smoking.

Administration, Cutaneous↗

PubMed2006

[Central giant cell granuloma of the mandible. Definition and differential diagnosis].

The synopsis of radiographic examination (uni- or multilocular radiolucency), histologic findings (giant cells throughout a benign fibroblastic matrix), blood chemistry analysis (normal serum parathyroid hormone) and clinical features provides the definitive diagnosis of giant cell granuloma, allowing the clearly defined surgical management of this lesion. The case history of a 48-year-old female patient who presented with a giant cell granuloma in the right mandible is used to illustrate this controversially discussed intra-osseous lesion. The potential therapeutic change from radical operative treatment, including functional maintenance, to conservative procedures is emphasized.

Diagnosis, Differential↗

PubMed2006

[Optimized auricular reconstruction with autologous cartilage. Experience from 120 cases].

INTRODUCTION: Auricular reconstruction with autologous cartilage has become well established in the last decade. By optimizing the technique, both the results and reliability have improved. OPERATION AND RESULTS: Based on our experience with 120 cases, we developed a concept that allows total ear reconstruction in two surgical steps. In the first operation, autologous rib cartilage is harvested and a natural framework created following the template of the opposite ear. The ear remnant is transposed and the framework placed in a subcutaneous pocket on the mastoid plane. After a healing period of around 6 weeks, the second operation reconstructs the auricular projection and the postauricular fold. The surgical procedure has to be adapted to difficult soft tissue situations. Most important is the specific analysis of local tissue and its resulting limitations. Deep scaring and skin grafting from previous operations need coverage of the framework with a subgaleal fascia flap. CONCLUSION: This optimized and adapted surgical procedure allows auricular reconstruction with autologous rib cartilage from the age of around 8 years into old age with good, reproducible results.

Adolescent↗

PubMed2006

[Effects of nicotine with special consideration given to tumorigenesis in the head and neck region].

BACKGROUND: Tumorigenesis is based on initiation, promotion, and progression, whereas tobacco smoke is a decisive predisposing factor for squamous cell carcinomas of the upper aerodigestive tract. A variety of tobacco smoke compounds is known to potentially initiate tumors, but the alkaloid nicotine is generally considered to induce addiction only. However, there is growing evidence that nicotine may also contribute to early stages of tumorigenesis. In the present study, a possible direct genotoxic potential of nicotine is investigated. MATERIAL AND METHODS: Lymphatic tissue of the tonsilla palatina of eight donors was harvested during surgery and incubated with nicotine. DNA damage was measured with the comet assay. RESULTS: Genotoxic effects of nicotine could be demonstrated. DISCUSSION: The results suggest a direct contribution of nicotine to tumor initiation and carcinogenesis.

Carcinoma, Squamous Cell↗

PubMed2006

[Correction of ear malformations with autologous rib cartilage].

INTRODUCTION: Ear malformations are mainly isolated deformations but exist also in combination with various syndromes. A visible malformation in cases of microtia is a problem for the entire family. Auricular reconstruction with autologous cartilage has been well established in the last decade. Optimization of the technique has led to improved and reliable results. OPERATION AND RESULTS: Based on the experience of 120 cases we developed a concept that allows total ear reconstruction in two operative steps. In the first operation autologous rib cartilage is harvested and a natural framework is created following the template from the opposite ear. The ear remnant is transposed and the framework placed in a subcutaneous pocket on the mastoid plane. After a healing period of around 6 weeks the second operation reconstructs the auricular projection and the retroauricular fold. CONCLUSION: Based on an individualized surgical treatment, auricular reconstruction with autologous rib cartilage are possible from the age of around 8 to the advanced period of life with reproducibly good results.

Adolescent↗

PubMed2005

[Dental injuries due to miniplate osteosynthesis. Classification, treatment management, complications, and prognosis].

BACKGROUND: In spite of a monocortical design, miniplate osteosynthesis can injure dental roots directly as well as damage dental substance indirectly by interrupting the apical blood stream. PURPOSE: The present retrospective study classifies different types of dental root trauma caused by monocortical screws, suggests therapeutic options based on diagnosis, and documents survival probability and prognosis after tooth trauma. PATIENTS AND METHODS: During a period of 11 years, 380 patients with permanent dentition underwent miniplate osteosynthesis for the treatment of mandibular fractures, 29 of whom sustained dental root trauma caused by drilling failure. These patients were clinically and radiographically examined for a follow-up time of not less than 38 months. RESULTS: The 29 patients could be classified into four different types of dental root trauma: 13 pulp injuries above the apical third of the root (type Ia), 6 pulp injuries in the apical third of the root or extradental lesions interrupting the apical blood stream (type Ib), 4 lesions to the central radicular dentin without pulp injury (type II), and 6 lesions to the peripheral radicular dentin and root cementum (type III). Of 13 type Ia injuries, 5 developed apical periodontitis and dilatation of the periodontal space. Therefore one root canal treatment and three apicoectomies were performed. One tooth had to be extracted. Three further type Ia injuries and two type Ib injuries showed root resorptions inducing two root canal treatments. One of six type Ib injuries required root canal treatment because of apical periodontitis. One of four type II injuries caused root resorption not requiring therapy. No relevant, pathological finding could be identified after type III injury. CONCLUSIONS: The type of dental root trauma caused by miniplate osteosynthesis determines therapy, complication rate, and survival of the injured tooth.

Adolescent↗

PubMed2005

Prefabrication of large fasciocutaneous flaps using an isolated arterialised vein as implanted vascular pedicle.

Flap prefabrication represents a new trend in microsurgical tissue transfer. Based on the concept of neovascularisation, in Chinchilla Bastard rabbits (n=40), an isolated venous pedicle dissected from the femoral and saphena magna vein was arterialised by end-to-end anastomosis to the femoral artery at the inguinal ligament. This arterialised venous loop was implanted beneath a random-pattern vascularised abdominal fasciocutaneous flap as large as 8 x 15 cm(2) to investigate the development of neovascularisation at various evaluating times of 4, 8, 12, 16 and 20 days. To prevent neoangiogenesis from occurring between the underlying vascular bed and abdominal flap, a silicone sheet with the corresponding dimension of 8 cm x 15 cm x 0.25 mm was placed and fixed on the abdominal wall. The flap viability and the neovascularisation process in the prefabricated abdominal skin flaps were evaluated by macroscopic observation, blood analysis, selective microangiography and histology. The experimental results showed that newly formed vessels originating from the implanted isolated venous pedicle were evident on the angiograms 4 days after pedicle implantation. In the 8- and 12-day groups, newly formed vessels became larger and some were connected to the originally available vasculature in the abdominal fasciocutaneous flaps. In the 20-day group, entire flaps were perfused by the blood flow supplied from the newly implanted venous pedicles through newly formed vessels and their vascular connections. This study indicated that large flap prefabrication can be created by implantation of an isolated arterialised venous pedicle into a random-pattern vascularised fasciocutaneous flap. Twenty days appears to be the minimal length of time required after arterialised venous pedicle implantation for the maturation of neovascularisation in the prefabricated flap.

Animals↗

PubMed2005

Navigation-assisted construction of an external ear canal using an autogenous foreskin graft.

Classic microtia is combined with external ear canal atresia and middle ear malformation. In order to evaluate whether an operation to improve hearing ability and the use of computer-assisted surgery are indicated, preoperative high-resolution navigation CT is mandatory. We combined atresia surgery and tympanoplasty with auricular reconstruction in the case of an 8-year-old boy with bilateral microtia, aural atresia and malformation of the middle ear. After creating an auricle framework with rib cartilage and transplanting it under the skin of the mastoid plane, we shifted it forward in the second step, and the new auditory canal was drilled under computer-assisted navigation and facial nerve monitoring. In the same operation, tympanoplasty was accomplished, and a silastic cylinder, wrapped into pieces of rib cartilage, was inserted into the constructed canal and removed 2 months later. For lining the new auditory canal, we used the patient's prepuce, harvested by elective circumcision.

Child↗

PubMed2004

[Tissue-engineered cartilage in a prefabricated microvascularized flap].

INTRODUCTION: In reconstructive surgery, the integration of tissue-engineered cartilage in a prefabricated free flap may make it possible to generate flaps combining a variety of tissue components to meet the special requirements of a particular defect. The aim of the present study was to establish the technique of prefabricating a microvascular free flap by implanting a vessel loop under a skin flap in a rabbit model. The second aim was to gather experience with prelaminating the flap with autologous tissue-engineered cartilage in terms of matrix development, inflammatory reaction and host-tissue interaction. METHODS: The microvascular flap was created by implanting a vessel loop under a random pattern abdominal skin flap. The tissue-engineered cartilage constructs were made by isolating chondrocytes from auricular biopsies. Following a period of amplification, the cells were seeded onto a non-woven scaffold made of a hyaluronic acid derivative and cultivated for 2-3 weeks. One cell-biomaterial construct was placed beneath the prefabricated flap, and the others were placed subcutaneously under the abdominal skin and intermuscularly at the lower extremity. In addition, a biomaterial sample without cells was placed subcutaneously as a control. All implanted specimens were left in position for 6 or 12 weeks. After explantation, the specimens were examined by histological and immunohistological methods. The prefabricated flap was analyzed by angiography. RESULTS: The prefabricated flaps showed a well-developed network of blood vessels formed by neovascularization between the implanted vessel loop and the original random-pattern blood supply. The tissue-engineered constructs remained stable in size and showed signs of tissue similar to hyaline cartilage, as evidenced by the expression of cartilage-specific collagen type II and proteoglycans. No hints of inflammatory reactions were observed. CONCLUSION: These results show the potential of prefabricated flaps as custom-made flaps for reconstructive surgery in difficult circumstances, more or less independent of anatomical prerequisites. Cartilage tissue engineering provides a 3-dimensional structure with minimal donor-site morbidity.

Animals↗

PubMed2004

[Experimental investigation of neovascularisation in large prefabricated flaps after arteriovenous pedicle implantation].

The principle of prefabricated flaps is based on the transformation of a formerly random-pattern vascularized flap, through implantation of a vascular pedicle, into a newly neovascularized axial flap, which can be transferred after a period of neovascularisation from the prepared donor site to the recipient site by using microvascular techniques. In 30 Chinchilla Bastard rabbits weighing from 3700 to 4200 g, a skeletonized arteriovenous pedicle with distal ligation harvested from the femoral and saphena magna artery and vein was implanted beneath an 8 x 15 cm abdominal skin flap to investigate the neovascularisation process in the flap over the course of time. In order to prevent neovascularisation occurring from the underlying vascular bed into the flap, a silicon sheet measuring 8 x 15 cm x 0.25 mm was placed and fixed on the abdominal wall. Flap vitality and neovascularisation process in prefabricated flaps were evaluated by macroscopic observation, blood analysis, selective microangiography, histology and scintigraphy at the various time intervals of 4, 8, 12, 16 and 20 days. The study results showed that newly formed vessels sprouting from the implanted pedicle were seen four days after pedicle implantation. With the retention time of pedicle in the flaps, they continued to grow, became meander and more dense. Respective connections between newly formed vessels and the originally available vasculature of the abdominal flap were markedly observed in the 12- and 16-day groups. Twenty days after prefabrication, the abdominal flap was completely perfused by the blood flow supplied from the newly implanted arteriovenous pedicle through newly formed vessels arising from the implanted pedicle and their rich vascular communications. The neovascularisation in the prefabricated flap consisted of the implanted pedicle, newly formed vessels, the originally available vasculature and their vascular connections. In comparison to the control group (the quantification was determined of 100 %), the vessel quantity in the prefabricated flap of the 20-day group had increased to 98.7 %. As a pre-clinical test, prefabricated flaps through arteriovenous pedicle implantation with special advantages can be a new useful method in plastic and reconstructive surgery.

Angiography↗

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

[Malformations of the auricle and their correction].

Owing to the stigma attached to auricular malformations, many patients request surgical correction. According to Weerda, such malformations can be classified into three grades of severity. Since the higher-grade malformations are often associated with malformation of the auditory canal and middle ear, and thus with hardness of hearing, early ENT evaluation of hearing problems is mandatory. Surgical correction of the auricle should not be attempted before the age of 5 years, and partial or total reconstruction in the case of anotia, is not considered before the age of 8. In such cases, autologous rib cartilage is needed to ensure construction of a natural-looking auricle. Standardized surgical procedures are available to correct the whole range of auricular malformations with good cosmetic results and a high level of patient satisfaction.

Age Factors↗

PubMed2002

[Dilated pneumosinus of the frontal sinus].

Pneumosinus dilatans is a rare disorder of the frontal sinus most commonly found in 20- to 40-year-old males. The deformity is caused by an abnormal enlargement of the frontal sinus by hyperpneumatization. A valve mechanism raising the pressure inside the sinus is regarded to be responsible for this condition. The diagnostic and surgical approach is presented in a 25-year-old male. A preoperative computed tomography (CT) scan in three planes illustrates the anatomical conditions and possible etiologic mechanisms. The surgical procedure is supposed to correct the esthetic deformity and the cause of the disorder. A bicoronal incision allows the best exposition of the frontal sinus. The osteoplastic correction is stabilized by titanium micro-osteosynthesis plates, which do not have to be removed. Functional endoscopic sinus surgery should be performed concomitantly in order to remove the cause of pneumosinus dilatans.

Adult↗

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

[Microtia: technique for external ear reconstruction with autologous rib cartilage].

Various methods for treatment of classic microtia are known. Beside a prosthesis, the most common way of auricle reconstruction is the use of autogenous rib cartilage; a process that requires two to three operations. In the first operation, rib cartilage is harvested from the 6th to the 9th rib. The base of the framework is the 6th and 7th rib cartilage which is taken under preservation of the synchondrosis. To mimic a 3-dimensional structure, the triangular fossa and scapha are carved into the groundplate and the 8th rib is fixed as a helical rim. After optimising the framework, it is placed in a subcutaneous pocket on the mastoid plane. In a second operation, approximately three months later, the auriculocephalic angle is reconstructed with a cartilage wedge, which is covered by a temporalis fascia flap and split skin-graft from the hairbearing skull. Commonly, a third operation is needed for minor refinements. Currently, autogenous rib cartilage is the ideal material available for ear reconstruction resulting in an excellent cosmetical outcome, although harvesting of the cartilage causes a specific donor-site morbidity. Operations improving the hearing ability by building up the external hearing channel and middle ear are mainly done in cases of bilateral microtia. Ear reconstruction with autogenous rib cartilage produces a replicable aesthetic result. The patients should be at least eight years old.

Adolescent↗

PubMed2001

[Local reconstruction of partial auricular defects].

INTRODUCTION: Partial auricular defects are often caused by resection of skin tumors. These patients are mainly older and often in reduced general condition. Therefore very expenditure surgical approaches seem to be dangerous. SURGICAL APPROACH: In most cases the resection of the tumor is possible in local anaesthesia. The reconstruction should be started after maintenance of the final histology. Next to the defect, the localisation leads to the right way of surgical treatment. Localized defects of the helical rim or auricular dorsum, concha and lobulus can be corrected with easy-to-perform local tissue transfers and flaps. Complex auricular defects with additional surgical steps like a neck dissection need general anaesthesia. As result of the preselected patients surgical single step reconstruction-procedure are preferable. In these patients, because of the size of the defect, previous operations or radiation larger local flaps from the neck region or the scalp are necessary. RESULTS AND CONCLUSION: With limited surgical expenditure most patients can obtain an aesthetically satisfying result. This avoids stigmatisation in an area that is hard to hide, which is important to elderly patients as well.

Age Factors↗

PubMed2000

[Highly malignant T-cell non-Hodgkin lymphoma (nasal type) of the hard palate].

The monomorphic clinical aspect of destructive mid-face lesions is characterised by inflammation, induration and granulomatous transformation. This feature can be caused by various infections, toxical noxa, Wegener's Granulomatosis and different neoplasms. The case of a 19 year old patient with EBV associated nasal type T-cell lymphoma located at the hard palate is presented. The diagnostic approach and difficulties in diagnosing this entity assessing by using multiple biopsies, serological and molecularbiological detection of EBV association and immunohistochemistry for atypic T-cells are elucidated. In the presented case the treatment with chemotherapy and irradiation following a well-defined therapy concept leaded to a three year recurrence-free survival so far. The comparison of the key-histological findings and the major differential diagnoses is mandatory to establish the final diagnosis of lymphoma. This is the basement for treating this disease with combined chemotherapy and irradiation for optimizing survival.

Adult↗

PubMed2000

[Color comparison of donor sites of free flaps and the face].

Microsurgical reconstructions of the face using free flaps from the body and the extremities often lead to imperfect aesthetic results. In order to find the optimal free-flap donor site with respect to its colour we compared the colour of the face and of typical free-flap donor sites. In a study of 19 healthy, untanned subjects with skin type II-III (Fitzpatrick 1988), we measured the colour of four facial areas and of ten common free-flap donor sites and compared them statistically. Measurements were carried out with a Minolta CR-300 chromameter and the CIELAB colour system. We found that the face itself can be divided into two statistically significant different colour regions. The forehead-, cheek- and mandible areas have a distinctly different colour than the nose. The donor sites showing the best colour match with the forehead-, cheek- and mandible area were pectoralis, lateral upper arm, radialis, fibula, and latissimus. The nose area is clearly darker and less colourful. For this reason the colour match of all the free-flap donor sites in our investigation is poorer. Here the best suited donor site area is still the dorsalis pedis area.

Face↗