Biomedical subjects

H G Kempf

Publications and source records attributed to H G Kempf.

At least 37 records · Page 2Linked to original sources

PubMed1996

Preservation of the non-rectangular cuticular plate/cell axis angle of outer hair cells.

Motile properties of outer hair cells (OHCs) may contribute to sharp tuning and amplification in the mammalian cochlea. Shape changes of isolated OHCs in response to various physical and chemical influences have been investigated intensively. However, determinations of shape may have been influenced by unanticipated effects of preparation and preservation of the OHCs investigated. Thus, in a first step, lengths of freshly isolated OHCs from the guinea pig cochlea were determined using a video-enhancing magnification system. The cuticular plate/cell axis angle (CP/CA angle) was then measured in native cells and under the influence of potassium chloride and potassium gluconate incubation. To show the influence of glutaraldehyde (GA) fixation on the isolated OHCs, fixative-dependent changes on cell length and CP/CA angle were recorded in native and preincubated OHCs. In these experiments, the cell length of vital isolated OHCs was between 41.5 micrometers, in the basal turn, and 103.7 micrometers, in the apical turn. The average CP/CA angle was 106 degrees +/- 4.2 degrees (n = 324 cells, turns 1-4) with no statistically significant differences for the four turns. Under the influence of potassium chloride, cell length was reduced by 8.1%. Potassium gluconate incubation led to a shortening of cell length, followed by a 5.3% increase after 5 min. The CP/CA angle under potassium chloride was decreased (97.0 degrees) and was then increased under the influence of potassium gluconate (110.7 degrees) as a result of cuticular plate tilting. Cell shrinkage after fixation depended on the fixative's osmolarity and on the GA concentration. Increased GA levels amplified cell shrinkage from 34% for hypo-osmolar solutions to 15% in iso-osmolar and 29% in hyperosmolar solutions. The CP/CA angle of native and incubated OHCs was not different from those fixed with GA. The present data provide a rational basis for isolated OHC shape parameters. Moreover, functionally induced changes can be better interpreted when OHCs are influenced by fixatives, as shown in the GA experiments.

Animals↗

PubMed1996

[Ionomer cement in cochlear implant surgery--applications and long-term outcome].

Over the last ten years about 850 cochlear implant operations were performed at the ENT department of Hannover Medizinische Hochschule. In most cases, intracochlear nucleus implants were used. For about two years the intracochlear Clarion device has also been used in 150 adults and children. For several years we have used ionomeric cement (lonocap, supplied by lonos, Seefeld/Germany) to fix the electrode array in the region of the posterior wall and the facial recess. Previously, the implant package was fixed by ionomeric cement. To evaluate the outcome of cement application, we conducted a prospective study of our implant patients during the period from 1991 to 1993. During regular reexamination over a period of two years postoperatively in 244 patients (122 male and 122 female patients, average age 17.6 years), we did not observe any complication related to the cement. Nearly all revision cases (n = 8) showed a stable contact between electrode array, bone, and cement. With increasing experience, we reduced the cement application and fixed the package with vicryl sutures in a precisely drilled bony bed. Contact of the cement with neural and cerebral structures should be avoided. In our experience ionomeric cement is a helpful tool in cochlear implant surgery with long-term stability and no rejection reactions.

Adolescent↗

PubMed1996

[Reconstructive surgery in the head-neck area with regional and free tissue transfer].

BACKGROUND: Operative treatment of head and neck cancer requires radical resection of the tumor with not only severe impairment of important functions like swallowing speech, and respiration but also aesthetic mutilation because of the exposed character of the head and neck region. Therefore the rehabilitation from a functional and cosmetic standpoint is an essential goal of treatment in addition to control of the malignant disease. Fortunately regional plastic surgery offers a variety of options for reconstruction of the defects to receive a solution tailored to each individual patient. PATIENTS: Between the years 1986 and 1996, 107 patients with advanced head and neck cancer were treated surgically by radical resection of the tumor and plastic reconstruction. In this study we made a retrospective analysis of the functional and aesthetic outcome of the techniques of reconstructive surgery we used for rehabilitation. The sex ratio was 79 males to 28 females. Average age was 59.4 years (ranging from 39 to 78 years). Most of the patients suffered from squamous cell carcinoma of the upper digestive tract (97 cases). The others included an adenocarcinoma of the paranasal sinuses (three cases), adenoid cystic cancer of the palate (two cases), squamous cell carcinoma of the temporal bone (two cases), two deep infiltrating basaliomas in the area of the nose and forehead and one chondrosarcoma of the neck. Our oncological concept includes a radical resection of the tumor and a onestep reconstruction of the defect, if the patient's general condition enables this approach. The surgical techniques we used include the approved pedicled myocutaneous flaps like the pectoralis major flap, latissimus dorsi flap (which can be also applied as a free microvascular tissue graft), temporalis muscle flap, and the free radial forearm flap. RESULTS: In previous years, the pedicled myocutaneous pectoralis-major- and latissimus-dorsi-flaps were used for reconstruction (n = 67), but the arc of rotation and the huge bulk of the graft are limiting factors for the indication of these techniques. The free forearm flap has increasingly been used to provide an excellent closure of large pharyngeal defects (n = 16), whereas the temporalis flap is useful for restoration after limited resection of the palate (n = 18). Beside these rather invasive procedures, aesthetic rehabilitation may be achieved with bone-anchored epithesis especially after exenteration of the orbit and ablation of the external ear in case of elderly patients with multiple morbidities (n = 5). In most cases, sufficient rehabilitation from the anatomical and functional point of view was possible even after large tumor resections. A main problem can be longstanding aspiration after resection of large areas of the pharyngeal mucosa (n = 8). Complications included eight cases of necrosis of the flaps and seven patients who developed significant seromas at the donor site. CONCLUSIONS: The potential of modern regional reconstructive surgery enables the surgeon to achieve anatomically and functionally rehabilitation in a one-step procedure in most cases, even after extended resection for head and neck cancer. One should be aware of the fact that these techniques do not offer a significant improvement of prognosis. As such, the aggressiveness of surgical therapy should remain in reasonable relation to the prognosis of the malignant disease.

Adenocarcinoma↗

PubMed1996

[Indications for middle ear obliteration within the scope of cochlear implant management].

BACKGROUND: Cochlear implants have gained worldwide acceptance as a reliable method of rehabilitation of profoundly hearing-impaired patients. Due to thorough patient selection major postoperative complications rarely occur and are flap related in most cases. Deafness can develop during chronic suppurative otitis media, either coincidentally or secondary to the medical treatment; normally this condition is regarded as a contraindication for cochlear implantation. In cases with a mastoid cavity after surgical treatment for cholesteatoma, the electrode covered only by the epithelial lining will likely become exposed or extruded. Therefore we suggest the obliteration of the middle ear cleft with abdominal fat and the blindsac closure of the external ear canal before cochlear implantation in these conditions. PATIENTS: The average age of our 12 patients was 48 years, whereas the youngest was 2 1/2 years of age. Due to chronic inflammatory ear disease. 11 patients had a mastoid cavity on both ears. Eight patients had a cholesteatoma, the chronic bone destroying process in the temporal bone of two female patients was considered as a fibroinflammatory pseudotumor. The child had a congenital deafness in both ears with a Mondini dysplasia in CT scan. She had already developed two episodes of pneumococcal meningitis which was caused by a defect in the stapes footplate through which a liquor-filled cystic sac herniated in the middle ear. Because of a massive liquorrhoea after opening of the sac, we decided to obliterate the middle ear cleft after successful insertion of the electrode array. RESULTS: All active electrodes of 10 Nucleus implants (Cochlear) and two Clarion devices (Advanced Bionics Corp.) were successfully inserted in the cochlea of the 12 patients. After an average follow-up of 15 months, a temporary facial palsy in one patient and an insufficient closure of a retroauricular fistula over the mastoid cavity in two cases were observed as postoperative complications. One patient with a fibroinflammatory pseudotumor developed a massive inflammatory reaction in the implanted ear two months after cochlear implantation, which could not be controlled by conservative treatment. The implant had to be removed and local conditions settled after administration of immunosuppressive treatment with cyclophosphamide. The patient received a new implant seven months ago. CONCLUSIONS: Implantation of a foreign body in a potentially infected space which communicates intracranially means a surgical challenge which can be managed by obliteration of the middle ear after subtotal petrosectomy with abdominal wall fat combined with a reliable closure of the external ear canal. In case of massive inflammation we would prefer a two-stage procedure.

Adipose Tissue↗

PubMed1996

Expression of matrix-metalloproteinases and their inhibitors in human cholesteatomas.

The proteolytic erosion of the temporal bone is the key event in the pathognomonic course of cholesteatoma progression. The molecular mechanisms of bone resorption, endangering the ossicles, the inner ear, the facial nerve, large vessels or the brain, are not understood. Recently, a new family of proteolytic enzymes, the matrix-metalloproteinases (MMP's) has been described and identified, which seems to play a pivotal role in matrix- and bone homeostasis and inflammatory osteolytic diseases, e.g. osteoarthritis and periodontitis. These enzymes are sophisticatedly controlled by specific inhibitors and activation cascades. We investigated whether human cholesteatoma tissue expresses MMP's and MMP-inhibitors. By immunocytochemistry of cholesteatoma-cryosections, the expression of MMP-2 (72 kD collagenase), MMP-9 (92 kD collagenase), and MMP-3 (stromelysin-1) could be seen to be strictly confined to the basal and suprabasal cell layer of the cholesteatoma epithelium. The neutrophil collagenase (MMP-8) showed a more disseminated expression in the epithelium and the granulation tissue as well. The tissue inhibitor of metalloproteases, TIMP-1, could be detected only in very limited areas of the granulation tissue in a quite randomized manner. Therefore, a derailment in favor of proteolysis of the normally tightly controlled MMP-system might be postulated. The results indicate that members of the MMP-family could play an active role in the molecular mechanisms of cholesteatoma invasion into the temporal bone. This offers new insights into the pathophysiology of the disease and of potential therapeutic approaches.

Adolescent↗

PubMed1995

[Liposarcoma in the head-neck area].

Between 1977 and 1992 four patients with liposarcomas of the head and neck region were treated and regularly reexamined at the ENT department of the University of Tubingen. Our patients were aged 19, 64, 66, and 73 years at primary diagnosis. Three patients were female and one was male. The tumors were located in cheek/parotid gland, the neck, the tracheoesophageal region and larynx/hypopharynx. In three patients complete primary resection was planned. In three cases further surgery was necessary due to recurrences. Two patients are free of tumor for seven and nine years, respectively. One patient was irradiated with 70 Gy four years after primary surgery since she had developed an unresectable recurrence. She died eleven years later aged 79 without residual liposarcoma (autopsy). One patient aged 76 rejected a radical resection and underwent a functional tumor reduction and is alive in fairly good condition. Histologically we found one myxoid and three well-differentiated liposarcomas. Metastatic spread was not observed. Wide tumor excision is the therapy of choice. Unresectable tumors can be irradiated successfully (up to 70 Gy are necessary). Representative studies on the value of chemotherapy have not yet been presented. The main factor in clinical behavior and prognosis of this rare tumor is the histological subtype. While well-differentiated and myxoid liposarcomas show almost no metastasis and good prognosis, the pleomorphic and round cell type do metastasis, recur more often, and have a significantly worse prognosis.

Adult↗

PubMed1995

[Carcinoma of the temporal bone--current diagnostic and therapeutic aspects].

BACKGROUND: Carcinoma of the external ear canal and the middle ear is a rather rare event and is especially seen in patients with chronic inflammatory ear disease. PATIENTS: Between 1993 and 1994, we treated seven patients with such a tumor, of which six proved to be a squamous cell carcinoma and one presumably adenocarcinoma. In three patients, the malignoma developed in a radical cavity of the ear and caused a facial palsy. Only two patients were without any discharge of the ear. Beside facial palsy, hemorrhagic otorrhea and otalgia were the leading symptoms. One patient presented with a bilateral painless swelling of the neck due to lymph node metastasis. Diagnosis was made by means of biopsy in only three patients and on the basis of a resected specimen after mastoidectomy in four patients. Angiography and computed tomography and magnetic resonance imaging studies were performed prior to treatment to determine the extent of the tumor. RESULTS: The tumor was resected by petrosectomy, parotidectomy, and neck dissection in 5 patients. Three times the margins of the histological specimen were free of tumor. Lymph node metastasis in the neck were seen in 5 cases, while distant metastasis did not occur. Two patients underwent primary irradiation, but a postoperative radiation therapy was performed five times. To date, three patients died after one year follow-up. CONCLUSIONS: Carcinoma of the temporal bone is a rare tumor, which can be treated only in case of early diagnosis.

Adenocarcinoma↗

PubMed1995

[Langerhans cell histiocytosis of the temporal bone].

BACKGROUND: The localized form of the Langerhans cell histiocytosis was referred to earlier as eosinophilic granuloma, which has the best prognosis of all histiocytosis syndromes concerning survival. The non-malignant proliferative disorder of the histiocytic system is still of unknown etiology. Characteristic radiographic signs are osteolytic lesions. PATIENT: We report on an otologic manifestation of a 20-year-old man's temporal bone, which developed three years after a successful treatment of an eosinophilic granuloma of the mandible. RESULTS: Surgery and low-dose irradiation led to a complete remission of the disease. Other manifestations of the disease were not detected until now. CONCLUSIONS: In the presence of chronic aural discharge, Langerhans cell histiocytosis must bei considered in differential diagnosis and a histopathological examination should be performed.

Adult↗

PubMed1995

[Detection of GABA(A) receptor mRNA in cochlear tissue. An in situ hybridization study].

Gamma-aminobutyric acid (GABA) and the GABAergic system play an important role in the efferent modulation of cochlear function. We examined surface preparations of guinea pig and mouse cochleae by in situ hybridization using radioactive labelled oligonucleotides for several subunits of the GABAA receptor. Frozen sections of rat and guinea pig brain (cortex, hippocampus, cerebellum) served as controls. In the mouse cochlea the mRNA of the alpha-1 and alpha-5, beta-1 and gamma-1 subunit were detected, while in guinea pig cochlea mRNA of the alpha-1, alpha-4, alpha-5, and gamma-1 subunit of the GABAA receptor were found. Positive signals were located in the regions of the outer hair cells and had a weaker intensity in the inner hair cells. In the brain sections the several subunits were detected in a variable distribution in the cerebellum, hippocampus and cortical regions. Rat specimens exhibited stronger signals than guinea pig brain sections. These investigations have extended previous results of immunocytochemical experiments from our laboratory demonstrating mRNA sequences of GABAA receptor subunits in the mammalian inner ear. Detection of these nucleotide sequences using surface preparations of the cochlea on a molecular level by in situ hybridization supports the importance of GABA as a cochlear neurotransmitter. Furthermore, it can be concluded that the mammalian cochlea is able to express a GABA-dependent neurotransmission system.

Animals↗

PubMed1994

Multiple metachronous skin squamous cell carcinomas and epidermodysplasia verruciformis in the head region: a human papilloma virus-associated disease.

Data from a young adult man with epidermodysplasia verruciformis (EV) and multiple metachronous spinaliomas in the head and neck region are presented. Diagnosis of this rare, human papilloma virus (HPV)-associated disease was based on: (1) Typical skin lesions, including viral warts, verruca plana-type lesions and pityriasis versicilor; (2) typical histological features, including "foamy giant keratinocytes"; (3) evidence of HPV 5, 8 and 20 in pityriasis versicilor-like lesions; (4) a cellular immunodeficiency due to a relative T-helper-cell deficit. No specific treatment of EV is known, so that therapy concentrates on early removal of spinaliomas and treatment of intercurrent infections. Since EV patients have numerous benign skin lesions and frequently develop metastatic and non-metastatic carcinomas, molecular changes of HPV during carcinogenesis can be studied.

Adult↗

PubMed1994

Gamma-aminobutyric acidA-receptor messenger ribonucleic acid (alpha-1 subunit) detection by in situ hybridization.

The inhibitory neurotransmitter gamma-aminobutyric acid (GABA) is most likely involved in the efferent cochlear neurotransmission. In situ hybridization (ISH) results in specific annealing of a labelled nucleic acid probe to complementary sequences in fixed tissue and allows subsequent visualization of the location of the probe. We used the ISH technique to localize messenger ribonucleic acid (mRNA) sequences of the alpha-1 subunit of the GABAA receptor with an S-35 labeled oligonucleotide probe. Experiments were performed in rat and guinea pig brain sections and surface tissue preparations of the guinea pig cochlea. Positive signals were obtained for the alpha-1 probe in cortical and hippocampal regions of the rat brain and had weaker expression in the guinea pig brain. Alpha-1 subunit mRNA was localized in Purkinje cells and in stellate and basket cells of the stratum moleculare in the rat and guinea pig cerebellum. In surface tissue preparations of the guinea pig cochlea mRNA sequences of the alpha-1 subunit were detectable with high signal expression. Positive signals were seen on both sides of the tunnel of Corti, predominantly in the region of the outer hair cells. The results indicate expression of GABAA-receptor mRNA in cochlear tissue, supporting the importance of GABAA receptors in cochlear neurotransmission.

Animals↗

PubMed1994

[Primary clinical manifestation of tuberculosis as an incidental finding in the head and neck area].

Between 1988 and 1992 12 patients were seen who had findings leading subsequently to the diagnosis of tuberculosis. The average age was 50 with a range from 22 to 88 years. Women outnumbered the male by 10 to 2 cases. The number of German patients equalled that of foreign patients. Tuberculosis was mainly localised in the cervical lymph nodes in 6 cases. One patient was seen with manifestation in each case at the palate, larynx, nasopharynx, cheek, parotis and middle ear. Diagnosis was made by histology alone six times, by evidence of acid-fast rods once and by both means in 5 cases. Preoperatively a malignant neoplasm was suspected in most patients, and neither CT nor ultrasound revealed a hint to tuberculosis. Tine-test was positive in all patients. Only in 3 patients was there an evidence of acid-fast rods in sputum and gastric juice. None of them suffered from AIDS. They were treated by combination of rifampicin, ethambutol, isoniazid and partially with pyrazinamide. No relapse was observed to date.

Adult↗

PubMed1994

[A clinically relevant variation of the superior thyroid artery].

Usually the superior thyroid artery is a branch of the external carotid artery. During a functional neck dissection in order to remove a metastasis of a tongue cancer we observed a variation of the origin of the vessel that was interesting from the surgeon's point of view. The artery rose from the A. carotis communis 3.5 cm below the bifurcation of the common carotid artery. Normally in this region no vessels leave the common carotid artery and therefore the knowledge of such variations is important for the exact identification of the neck vessels during surgery to avoid a fatal mix-up with the internal carotid artery.

Arteries↗

PubMed1994

[Diagnosis and therapy of olfactory neuroblastoma].

Esthesioneuroblastomas (EN) exhibit problems in early diagnosis and therapy due to their localization at the frontal skull base. Analysis of six cases with EN (four male, two female; average age, 34.8 years) showed atypical initial symptoms, beginning as nasal bleeding, hyposmia and frontal headache. CT scans demonstrated hypo- to isodense tumors at the anterior skull base with extension to the sinuses and orbits. Five patients were operated on by an extranasal approach; one patient required orbital exenteration with later reconstructive surgery of the orbit by a microvascularly adapted forearm flap. One patient underwent a neurosurgical procedure first that was followed by chemotherapy and stereotactically guided radiation. One patient died 1 year after onset of therapy due to intracranial tumor. One patient developed lung metastasis 5 years after treatment. Four patients remain in clinical remission and receive regular follow-ups. Our analysis shows the guarded prognosis of EN despite multimodality therapy. This includes the problems of advanced disease with complications of surgery and radiation. All therapeutic procedures should be planned in collaboration with otolaryngologists, neurosurgeons and radiotherapists. New computer-aided and stereotactically guided radiation procedures can be helpful, especially in patients with extensive disease.

Adolescent↗

PubMed1993

[Ectopic teeth in the area of the paranasal sinuses].

In contrast to dentogenious affections of the sinus maxillaris ectopic or supernumerary teeth in the paranasal sinuses are seldom. Ectopic teeth located at the ostium of the sinus maxillaris are rare, intranasal teeth are very rare and ectopic/supernumerary teeth in the sinus etmoidalis are a curiosity. We report about two patients with such ectopic teeth. A 55 year old woman had a rootless tooth in her right sinus ethmoidalis which had caused a "pseudopolyposis" with consecutive nasal airway obstruction and severe headache. A 59 year old man had ectopic teeth in both sinus maxillaris which obstructed the left ostium, causing dumbness of the left cheek and severe headache. Both patients have been cured by operation. However the presented patients demonstrate that even elaborated radiological efforts could not prove diagnosis. The etiology, diagnostical steps and treatment of these teeth are discussed. The surrounding soft tissue should be examined histologically after resection of such a tooth to prevent the development of a residual cyst and to notice the extremely rare development of malignancies deriving from the highly potential tissue of the dental follicle.

Diagnosis, Differential↗

PubMed1993

[Correlation between inner ear disorders and temporomandibular joint diseases].

Acute and chronic inner ear diseases involve many etiological factors, some as yet unknown. ENT-specific, orthopedic, hemorrheological, immunological and neurological disorders can affect the cochleovestibular system and induce hearing loss, vertigo and/ortinnitus. We performed a prospective study to analyze factors of the dentognathological system and of the temporomandibular joint that can influence acute and chronic inner ear dysfunctions. A total of 138 patients (49.3% female, 50.9% male) receiving clinical treatment for inner ear dysfunctions (12.3% chronic sensorineural hearing loss, 15.2% Ménière's disease, 52.2% sudden hearing loss, 13.8% isolated tinnitus, 6.5% recurrent hearing loss) underwent a prospective dental and gnathological examination. In particular, the patient's dental status and a functional investigation of the masticatory muscles and the temporomandibular joint were analyzed. In 20.3% patients the examination showed no pathology of the dentognathological system. In contrast, there were pathological findings in 110 patients (79.7%): in 43.5% a temporomandibular joint syndrome was diagnosed, in 29% parafunction of the occlusion, and in 35% a myopathy of the masticatory muscles. Additionally 32.6% patients showed dental disorders that required treatment; 11.65% had problems with dentures and 20.3% malpositioned wisdom teeth. In 16 patients the recommended dental treatment was followed up and improvement of otological symptoms was found in 56.6%. The present investigation shows that many patients with inner ear dysfunction suffer from dentognathological disorders. For a subgroup of patients there exists the possibility of improving otological symptoms by dental treatment. Therefore we recommend a dentognathological examination in patients with inner ear dysfunctions of unknown etiology.

Adult↗

PubMed1993

[Perspectives of molecular genetics of hearing disorders].

In the last few years research efforts have succeeded in detectury the genetic background of several hereditary hearing disorders by molecular biological methods. The genetic code was been decoded for Neurofibromatosis types 1 and 2, as well as for such X-linked diseases as Alport's syndrome or Norrie's disease. Besides the classic genetic tools as chromosomal analysis, molecular biological techniques and methods have become important clinically for the ENT-specialist. In the present review we show the principles and applications of DNA-and RNA-analysis with hybridization techniques in Southern- and Northern-blot techniques, as well as in-situ hybridization and polymerase chain reaction (PCR). These molecular biological techniques will help improve the detection and analysis of hereditary inner ear disorders, but also be able to study in greater detail tumor carcinogenesis and mutagenesis. The various techniques are explained and the applications are demonstrated.

Chromosome Aberrations↗

PubMed1992

[Wegener's granulomatosis: otologic and clinico-immunologic aspects].

Clinical, audiometric and immunological data of 26 patients with histological proven Wegener's granulomatosis are presented. In 21 patients the middle ear was involved with serous otitis media, adhesive process or subacute otitis media. 28 of 36 audiometric examinations showed a mild to moderate sensorineural hearing loss. One ear did not recover from a sudden deafness in the early stage of the disease despite of immunosuppressive therapy. Beside clinical and morphological findings in Wegener's granulomatosis the detection of anticytoplasmic antibodies against neutrophil granulocytes (ANCA) is a reliable method in diagnosing the disease. In the present study, the serum of 19 out of 26 patients with histologically proven Wegener's granulomatosis was examined for ANCA by immunofluorescence test. In high activity stage of Wegener's granulomatosis all sera showed a positive ANCA-test. 39 patients with systemic vasculitis served as controls. Only two sera from patients with leucocytoclastic vasculitis and two with panarteriitis nodosa were ANCA positive. The follow-up (35 serum probes) of 8 patients showed no ANCA after immunosuppressive induced remission. In four histologically detected cases of recurrence ANCAs were positive again. ANCAs are very useful in primary diagnosis of Wegener's granulomatosis as well as in the follow-up. In addition, the analysis reveals, that immunosuppressive therapy with cyclophosphamide and prednisone facilitates complete remission and a long survival rate of patients with Wegener's granulomatosis.

Adult↗