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Biomedical subjects

I Baumann

Publications and source records attributed to I Baumann.

At least 37 records · Page 2Linked to original sources
PubMed2001

Total implantation of the active hearing implant TICA for middle ear disease: a temporal bone study.

A subpopulation of hearing-impaired patients has conductive hearing loss that cannot be improved by classic tympanoplasty. Other patients have a mixed hearing loss and cannot be helped by present forms of ear surgery or by hearing aids. Possible help for some patients may come from current implantable hearing devices if these are modified for the patient's specific anatomic situation. The TICA LZ 3001 is a hearing implant for total implantation used to treat moderate to severe sensorineural hearing loss. Most patients who use it have a normal ossicular chain that allows coupling of the implant to the incus. The present temporal bone study demonstrates that the TICA can also be used in patients with an interrupted ossicular chain. If the incus long process shows a defect, the TICA may be coupled to the incus body, and connection between the stapes and the long process of the incus can be achieved with a commercially available titanium-angle prosthesis or liquid ionomeric cement. In cases of an absent incus, the coupling axis of the transducer may be coupled to the stapes head via a modified coupling element. With an absent stapes, the coupling axis may be coupled directly to the perilymph by a coupling element similar to a gold stapes prosthesis.

Ear, Middle↗
PubMed2001

Spindle cell lipoma of the parapharyngeal space: first report of a case.

Spindle cell lipomas are usually located in the subcutaneous tissue of the back, shoulders, and neck. To our knowledge, the presence of such a tumor in the parapharyngeal space has not yet been described. We evaluated a 45-year-old man with a tender swelling of the right parotid area that had reached the submandibular area. Clinical examination and magnetic resonance imaging revealed the presence of a tumor that coated the parotid area laterally and extended into the center of the parapharyngeal space, thus causing a dislocation of the pharyngeal muscles and mucosa. We performed a total parotidectomy and submandibulectomy on the right side and extirpated the parapharyngeal tumor. We were able to spare the facial nerve, and no facial paralysis occurred. Histologic examination revealed an atypical lipomatous tumor with a remarkably large portion of spindles.

Biopsy, Needle↗
PubMed2000

Hodgkin's disease and peripheral T-cell lymphoma: composite lymphoma with evidence of Epstein-Barr virus infection.

This paper reports the case of a patient with a composite lymphoma consisting of nodular sclerosing Hodgkin's disease and peripheral T-cell lymphoma. The Hodgkin and Reed-Sternberg (HRS) cells harboured the Epstein-Barr virus (EBV) and displayed a type II EBV latency (LMP1(+)/EBNA2(-)), whereas the neoplastic T-cells were EBV-negative. Four years later, the patient presented with a relapse of the peripheral T-cell lymphoma. In situ hybridization revealed numerous EBV-carrying lymphocytes, which were shown to be polyclonal B-cells with a latency III pattern of EBV gene expression (LMP1(+)/EBNA2(+)). This observation suggests that impairment of EBV-specific immunity in the micro-environment of T-cell lymphomas may facilitate the outgrowth of EBV-carrying B-lymphocytes and emphasizes the importance of determining the phenotype of EBV-infected cells, particularly when studying T-cell lymphomas. The results further suggest that the HRS cells and neoplastic T-cells were of different clonal origins. The detection of EBV-carrying cell populations admixed with the neoplastic T-cells at primary presentation and at relapse raises the possibility that the growth of the T-cell lymphoma was dependent on the presence of such cells.

Aged↗
PubMed2000

Characterisation of NF-kappa B complexes in Theileria parva-transformedT cells.

Transformation of T cells by the intracellular parasite Theileria parva is accompanied by constitutive I-kappa B degradation and NF-kappa B activation, a process which is essential to prevent the spontaneous apoptosis of these parasite-transformed cells. NF-kappa B-mediated responses are regulated by selective combinations of NF-kappa B proteins as homo- or heterodimers and by distinct kappa B motifs. We characterised the NF-kappa B complexes induced by T. parva infection in TpM(803) T cells. By western blot, we demonstrated that all members of the NF-kappa B/Rel family of proteins translocate to the nucleus of infected cells. Using two different kappa B oligonucleotides (kappa B-1 and kappa B-2), both containing the decameric consensus kappa B motif (GGGACTTTCC), clearly distinct patterns of DNA binding activities could be demonstrated in electrophoretic mobility shift assays. Supershift analysis and UV cross-linking assays showed that complexes binding to kappa B-1 consisted of p50, p65 and RelB homo and/or heterodimers. We could also detect an association of ATF-2 and c-Fos with one of the complexes. The HIV-derived kappa B-2 oligo only bound p50 and p65. Additionally, several agents known to inhibit a wide range of NF-kappa B activation pathways had no inhibitory effect on the activation of NF-kappa B DNA binding in TpM(803) T cells.

Activating Transcription Factor 2↗
PubMed2000

[Radiation exposure during spiral-CT of the paranasal sinuses].

PURPOSE: Determination of the radiation doses in spiral CT of the paranasal sinuses using a variety of mAs values and scan protocols. MATERIAL AND METHODS: CT examinations of the paranasal sinuses were performed using an Alderson-Rando phantom. Radiation dose was determined by LiF-TLD at the level of high risk organs in the head and neck region for combinations of different scan parameters (2/3, 3/3, 3/4 mm) and decreasing charges (200, 150, 100, 50, 25 mAs) on a spiral CT. Additional measurements were performed on three other CT scanners using the 2/3 mm protocol at 50 mAs, and a single slice technique (5/5 mm) on one scanner. RESULTS: The lowest dose values found were 1.88 mGy for the eye lenses, 1.35 mGy for the parotid gland, 0.03 mGy for the thyroid gland and 0.1 mGy for the medulla oblongata using 2 mm collimation and 3 mm table feed at 25 mAs. Maximal dose values resulted using the 3/3 mm protocol at 200 mAs (31.00 mGy for the eye lense, 0.65 mGy for the thyroid gland). There were no significant differences found between the different CT scanners. CONCLUSIONS: Using up-to-date CT scanners, radiation exposure may be reduced by a factor of 15-20 compared to that of conventional CT technique. Thus, the exposure of the eye lens comes to only a thousandth of the value supposedly inducing a cataract, as published by the ICRP.

Humans↗
PubMed2000

[Locally recurring extramedullary plasmacytoma of the upper aerodigestive tract].

BACKGROUND: Extramedullary plasmacytomas (EMP) are plasma cell tumors in which by definition the primary tumor is extramedullary. Most of them are found in the upper aerodigestive tract. PATIENTS: In this study we describe 3 patients with EMP. The first case is a locally recurrent EMP with recurrent involvement of cervical lymph nodes. The first manifestation of EMP was 31 years ago. Hence, this is one of the longest clinical courses of recurrent EMP ever described in the literature. Case 2 is a locally aggressive recurrent EMP. Case 3 is a localized solitary EMP that could be successfully treated by surgery alone. RESULTS AND CONCLUSIONS: Different classifications of EMP described in the literature are discussed. If these classifications are applied to our cases neither the tumor stage nor the histological picture allow definite conclusions about the prognoses to be drawn. Metastases in regional lymph nodes do not necessarily mean a worse prognosis. Overall, compared to MM with a ten year survival rate of 18% the prognosis is more favorable in EMP with a ten year survival rate of 50%. After a generalized plasma cell neoplasia has been excluded EMP in the head and neck should be treated like a locally aggressive and potentially metastatic tumor. From our experiences we recommend a primary surgical therapy followed by radiation therapy if necessary.

Aged↗
PubMed1998

Congenital myasthenic syndromes in two kinships with end-plate acetylcholine receptor and utrophin deficiency.

We studied two families with five affected members suffering from ptosis and slowly progressive limb-girdle muscle weakness. All patients had abnormal decremental response on low-frequency nerve stimulation, but there were no repetitive responses to single stimuli. The patients improved on anti-acetylcholinesterase drugs. Intercostal muscle was obtained for special studies from one patient of each family. In vitro microelectrode studies were done in Patient 1. Miniature end-plate potentials were of low amplitude, and the quantal content of the evoked end-plate potentials was normal. Light microscopy revealed a marked type 1 fiber predominance. Acetylcholinesterase reactivity was dispersed over increased length of individual fibers in Patient 2. On morphometry of the end-plate ultrastructure, the number of secondary synaptic clefts per neuromuscular junction and the expansion of the postsynaptic area were markedly reduced. In Patient 1, but not in Patient 2, the envelopment of the nerve terminal by Schwann cell was increased. Acetylcholine-receptor (AChR) density was reduced as judged by the reduced immunoreactivity to antibodies against different receptor subunits. Immunohistochemical analysis of proteins known to be involved in orchestrating the end-plate structure showed deficiency of the AChR-associated protein utrophin. These patients appear to have a defect in the development or maintenance of the postsynaptic clefts; whether this defect results from or causes a reduced expression of utrophin or AChR is unclear.

Adult↗
PubMed1997

[Autologous tissue in initial type I and type III tympanoplasty operations in chronic suppurative otitis media].

We reviewed 192 patients who had been treated for chronic otitis media. All operations were carried out at the Department of Otolaryngology, University of Tübingen. No patient had a previous ear operation and revision operations were excluded. The observation period varied from a minimum of 1 year to a maximum of 4 1/2 years. The ossicular chain was partially destroyed in 43 ears (22.4%). Ossiculoplasty was performed using autologous ossicles. An inens was used in 31 ears and a malleus in 12 cases. The overall failure rate was 20.8%. Most recurrent perforations were found in middle-aged patients. Children had only a 14% incidence of recurrent perforations. Fascia was the material associated with the highest failure rate (28.6%). After using perichondrium 6.8% of the cases had recurrent perforations, whereas the perichondrium-cartilage transplant was not successful in 4.8%. Overall, 62.7% of the patients were found to have an air-bone gap of 10 dB or less at 1.5 kHz 3-6 months after surgery. An air-bone gap of 20 dB or less was found in 91.2% of the patients. The main problem seen in the patients with chronic otitis media was not reconstruction of the ossicular chain but a lasting closure of the tympanic membrane. The perichondrium-cartilage transplant permitted the best results and is now recommended especially for patients with unfavorable middle ear conditions. A long-lasting closure of the tympanic membrane was also found in children (< or = 15 years of age). For this reason we also recommend an early operation in order to allow children to lead a normal life.

Adolescent↗
PubMed1997

[Inverted papilloma of the nose and paranasal sinuses--diagnosis, surgical procedure and studies of cytokeratin profile].

BACKGROUND: Inverted papilloma is a benign sinunasal tumor, characterized by aggressive nature and tendency to recur. This tumor also has a significant malignant potential (10%). In spite of extensive research in the past the origin of inverted papilloma is not known. METHODS: A retrospective analysis of the clinical data of 28 patients suffering from inverted papilloma of the nose and paranasal sinuses with regard to symptoms, clinical examination, computed tomography findings, and operative management was performed. Furthermore, immunohistochemical examinations of the cytokeratin profile of 12 specimens were carried out. RESULTS: The most presenting symptoms were unilateral nasal obstruction (17.61%) and rhinorrhea (7.25%). Polyposis was seen endoscopically in 19 cases (68%), so that in many patients in inverted papilloma became suspicious in the CT scan. The surgical therapy was dictated by the extent of the tumor, so that the tumor was treated by lateral rhinotomy (n = 17), midfacial degloving (n = 5), endonasal endoscopic surgery (n = 5), and craniofacial resection due to an infiltration of the frontal skull base (n = 1). An immunohistochemical analysis of the cytokeratin profile revealed for the first time that the inverted papilloma, when compared to the normal surface epithelium of the nasal cavity and the paranasal sinuses, exhibits increased expression of cytokeratin 5, typical for basal cells, and cytokeratin 13, typical for squamous epithelial cells. CONCLUSIONS: Based on our results we recommend that the endonasal approach is reliable for processes restricted to the middle nasal meatus and the anterior and middle ethmoid cells. Inverted papilloma of the frontal sinus, retrobulbar and supraorbital ethmoid cells, and laterocaudal parts of the maxillary sinus should be resected via lateral rhinotomy or midfacial degloving. The findings of immunohistochemical examinations suggest that inverted papilloma is derived from a cytokeratin 5-immunoreactive cell of the basal layer of the mucosa.

Adult↗
PubMed1997

[Tactile sensor for tissue differentiation in minimally invasive ENT surgery].

BACKGROUND: In endoscopic surgery, stereoscopic vision and tactile information about tissue consistency are no longer available to the surgeon. METHODS: To compensate for these sensory deficits, various tissues can be characterized with an electromechanical sensor that records their resonance frequencies. In the future, the sensor will be integrated into surgical instruments, providing the surgeon with information about tactile properties of the tissue. We determined the impedance of tissues removed interoperatively (nasal polyps, lymph nodes, cartilage, bone) and different bony structures in a skull specimen. The examinations were carried out with an experimental setup and subsequently with a prototype of the tactile sensor. RESULTS: Resonance frequency increased with tissue hardness. Measurements with the experimental setup showed resonance frequencies for soft tissues between 15 and 30 Hz. We found that the bony septa of the ethmoid have a resonance frequency of 240-320 Hz and the thicker bony structures at the frontal skull base have a frequency of 780-930 Hz. Measurements of tumors in the upper aerodigestive tract showed that it is possible to differentiate between healthy mucosa, carcinomateous infiltrated mucosa, and carcinomateous undermined mucosa. In case of undermining tumor, the resonance frequency was one third higher than healthy mucosa. These results obtained with the experimental setup were reproduced with the tactile sensor prototype. CONCLUSIONS: The use of tactile information in endoscopic otolaryngological surgery may improve intraoperative tissue differentiation in the future. The safety of minimal invasive operations in head and neck surgery can be increased.

Endoscopes↗
PubMed1997

Therapy of myasthenic crisis.

OBJECTIVES: To investigate the frequency, causes, and characteristic features of the course of isolated myasthenic crisis (defined as acute respiratory failure with the need for mechanical ventilation). To compare the effectiveness of three different therapeutic regimens (i.e., continuous intravenous infusion of pyridostigmine, pyridostigmine plus prednisolone, and plasma exchange) in terms of duration of ventilation and outcome of patients with myasthenic crisis. DESIGN: Population-based retrospective study covering the period 1970 to 1995. SETTING: University hospital, center for myasthenia gravis in Saxony, Germany. PATIENTS: Of 235 patients with myasthenia gravis treated at our institution, 44 patients developed a total of 63 myasthenic crises (average annual incidence 2.5%). INTERVENTIONS: Myasthenic crises were treated with pyridostigmine (n = 24), pyridostigmine plus prednisolone (n = 18), and plasma exchange (n = 21). MEASUREMENTS AND MAIN RESULTS: There were no significant differences between the three treatment groups with respect to clinical characteristics, duration of mechanical ventilation, complications, and outcome on release from intensive care and after 3 months. Eleven (17%) patients had severe cardiac arrhythmia, which ended fatally for six patients. CONCLUSIONS: None of the therapeutic regimens applied demonstrated any advantage over the others. All three regimens used were found to be effective and should be applied depending on the circumstances prevailing. Patients with myasthenic crisis must undergo careful cardiac monitoring, and temporary pace-making should be provided where clinically indicated.

Humans↗
PubMed1997

Minimal invasive ear, nose and throat surgery--advances through modern technologies.

Three fundamentals have to be fulfilled to optimize minimally invasive surgery: three-dimensional imaging, free maneuverability of the instruments, sensorial feedback. Projection of two pictures from a stereoendoscope and subsequent separation with a LCD shutter allows three-dimensional videoendoscopy to be performed. A high frequency shutter technique (100/120 Hz) presents pictures from the two video cameras to the right and left eye, respectively, so that the surgeon has spatial vision of the operative field. Steerable instruments have four components: a control unit, rigid shaft, steerable multijoint, distal effector. The steerable multijoints give two additional degrees of freedom compared to conventional rigid instruments in endoscopic surgery. For intuitive movements, however, an electronic control system is necessary that is comparable to the "master slave" priniciple in remote technology. A remote manipulator system with six degrees of freedom is now available. Additionally, a multifunctional distal tip permits different surgical steps to be performed without changing the instrument. For better control of the instrument and the operative procedure tactile feedback can be achieved with appropriate microsensor system. Recent projects suggest that an artificial sensor system can be established within the foreseeable future.

Ear↗
PubMed1996

[Free transplanted, microvascular reanastomosed forearm flap for reconstruction of the mouth cavity and oropharynx. Clinical and morphologic findings with special reference to reinnervation].

It remains a controversial question whether or not the anastomosis of sensory nerves is necessary in free transplants of microvascularly reanastomosed radial forearm flaps in the oral cavity and oropharynx. Some authors perform this routinely because they expect fewer complications in a skin with a sensory nerve supply. We carried out clinical and morphological examinations in 20 patients in order to determine the sensory innervation of the transplanted tissue. All patients received free transplants of microvasculary reanastomosed radial forearm flaps during a tumor operation in the oral cavity or oropharynx. Postoperative wound healing proceeded without complications in all but three cases, but these disturbances were insufficient to explain any deficit in sensation in the operated areas. Following surgery, sensation was determined clinically by two-point discrimination. Morphological studies of 20 flap biopsies using conventional colored light microscopy demonstrated nerve fibers in 14 of the biopsies. Immunohistochemical investigations also showed the presence of small nerve fibers by proving S-100 positive Schwann cells. We could not find a correlation between the demonstration of nerve fibers and the use of radiation (or an increased radiation dosage) following surgery. These findings suggest that nerve regeneration was completed just before the 6th postoperative month, which was the earliest time recorded in this study. Perivascular (vegetative) nerves showed a delayed regeneration and could be demonstrated only 36 months after operation. Histological investigations of the transplanted tissue showed a decrease in keratin with a partial increase in parakeratosis, a loss of skin structures and nearly always chronic inflammation. Our findings verify that a sensory innervation is possible in free transplanted radial forearm flaps by the regeneration of nerves coming from the transplantation bed and/or adjacent (oral) mucosa. This leads to a sensation comparable to that of healthy mucosa. These findings also indicate that there is no need for the anastomosis of sensory nerves during transplant surgery.

Adult↗
PubMed1996

Image analysis detects lineage-specific morphologic markers in leukemic blast cells.

This report outlines the morphologic classification of acute myeloid (AML: French-American-British FAB classification: M1) and lymphoid (ALL) leukemia by automatic image analysis and the correlation to immunologic and cytochemical classification. The investigation was carried out on Romanowsky-Giemsa stained bone marrow (n = 15) and blood smears (n = 10) from 25 patients with primary acute leukemia. The cases had been classified as of myeloid or lymphoid origin by three hematologic centers using immunochemistry or cytochemistry, but the specimens were submitted to the authors' laboratory without the diagnosis. The nuclear and cytoplasmic pattern of the blast cells were analyzed by a high resolution image analysis system and the measured and calculated cell features were sorted by means of a classifier program (CART). The image analysis classification was then compared with the immunophenotypical and cytochemical classification. Blood blast cells showed nuclear features that were significantly correlated to a myeloid or lymphoid immunophenotype. In contrast, bone marrow blast cells displayed overlapping and therefore nondiscriminating nuclear features. However, by generating a learning data set using the immunophenotypes the classifier program found specific cytoplasmic features that eventually permitted a differentiation into myeloid or lymphoid subtypes. In summary, the authors suggest that high resolution image analysis of leukemic blast cells detect nuclear and cytoplasmic features that are associated with the immunophenotype and therefore with the lineage determination of the cell. With this new objective and reproducible approach of morphologic cell analysis, it might not only be possible to classify blast cells with minimal cellular differentiation, but furthermore to discover prognostic features because the remarkable difference in classification quality between blood and bone marrow blast cells reported in this study, might be of biologic relevance and requires further investigation.

Adolescent↗