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Biomedical subjects

W Mann

Publications and source records attributed to W Mann.

At least 55 records · Page 3Linked to original sources
PubMed1998

Indications for computer-assisted surgery in otorhinolaryngology.

Indications for the use of computer-assisted surgery (CAS) in otorhinolaryngology can be grouped into several domains including the following: difficult cases involving the anterior, middle, and posterior skull base, especially the rhinobasis or laterobasis, and diseases of the petrous bone, the infratemporal fossa, the retromaxillar space, and the orbit; extended paranasal sinus surgery and revision cases with surgically altered anatomic landmarks; and use for educational purposes where CAS can provide better instruction in surgical anatomy by relating the surgical field to radiological sectional images. A new field for CAS is surgery of the inferior neck soft tissues or pathologic processes reaching into the upper mediastinum.

Humans↗
PubMed1998

[Postoperative vestibular compensation and facial nerve function after acoustic neuroma operation. Relation to origin of the tumors].

Within the battery of functional tests used in patients considered to have an acoustic neuroma, the use of vestibular examination has been reduced by the widespread use of magnetic resonance imaging. Especially small tumors often show normal or atypical results in electronystagmographic examinations (ENG). The purpose of the present study was to determine the diagnostic value of preoperative vestibular diagnosis in predicting the origin of an acoustic neuroma, as well as the duration of postoperative vestibular compensation and facial nerve function. Sixty-seven patients with intraoperatively confirmed tumor origins were examined preoperatively by ENG and electroneurography in addition to careful clinical examination. Group 1 (n = 45) consisted of patients with tumor originating from the inferior vestibular nerve and group 2 (n = 22) had tumor involving the superior vestibular nerve. Postoperatively, facial nerve function was determined by using the House grading system and vestibular function was defined by ENG 3, 6 and 12 months after surgery. Forty-seven percent of the patients in group 1 showed a pathologic caloric response compared to 64% in group 2. When patients had only a small tumor (< 1 cm), 27% of the patients in group 1 and 71% in group 2 had abnormal caloric results. Vestibular recovery was prolonged in group 1, but a statistically significant difference in postoperative facial nerve function could not be found. These findings confirm that especially small tumors arising from the inferior vestibular nerve can remain undetected by using ENG for diagnosis.

Electronystagmography↗
PubMed1998

[Paranasal sinus carcinomas with orbital involvement].

Fifteen patients at the University of Mainz were diagnosed as having T3 or T4 carcinomas of the paranasal sinuses that invaded the orbit. Treatment involved surgical resections of tumor with adjacent periorbita but without enucleation in an attempt to preserve vision and/or cosmesis. Survival rates and especially the rate, time and locations of recurrences were investigated. Analysis of the data revealed that preservation of the eye in these cases with advanced sinus carcinomas with orbital tumor involvement did not seem to worsen prognosis. The individual gain in terms of quality of life through the preservation of vision and cosmesis seems to justify the surgical approach used.

Female↗
PubMed1998

[Function of the eustachian tube in epitympanic retraction pockets].

There are different hypotheses for the development of epitympanic retraction pockets. These can occur as the result of an inflammatory process and negative pressure in the middle ear spaces. Anatomic bottlenecks in the middle ear favor diminished inflation of the epitympanic space. The eustachian tube provides pressure equilibration in the middle ear. Its dysfunction involving tubal opening or closing is thought to be the main reason for a permanent negative pressure in the middle ear. A patulous eustachian tube is now claimed for prolonged negative pressure in the middle ear and is caused by a so-called "sniffing" habit. The purpose of this study was to elucidate objectively the frequency of patulous eustachian tubes in ears with epitympanic retraction pockets. We examined passive tubal function in 41 patients with 50 epitympanic retraction pockets by using dual impedance in a pressure chamber. We identified three stages of epitympanic retraction pockets. Stage 1 involved a mobile and controllable retraction pocket; stage 2 corresponded with a fixed but controllable pocket, whereas stage 3 described a fixed pocket that was developing into a cholesteatoma. Results were compared with the function tests of 100 healthy ears in 50 normal individuals. We found 27 patulous eustachian tubes in patients with epitympanic retraction pockets, 22 of which occurred in affected ears while only 2 patulous tubes were found in the group of the healthy ears. Tubal opening pressure (P < 0.001) and tubal closing pressure (P < 0.01) were significantly lower in ears with epitympanic retraction pockets than in healthy ears.

Adult↗
PubMed1998

Use of electron spectroscopic imaging to determine element composition of the melanin granules in the stria vascularis of the guinea pig.

Electron spectroscopic imaging (ESI) was used to analyze the element content of melanin granules in the stria vascularis seen in ultrathin sections of Spurr-embedded cochleae of the guinea pig. To determine element composition, ESI images were taken at different ionization edges, and non-specific background signals were subtracted digitally by an image processing system. The presence of calcium and nitrogen in the melanin granules could be demonstrated clearly. The calcium identified in the melanin granules was then compared with the spatial distributions of calcium binding sites after the application of an antimonate precipitation method, which was used to localize loosely bound calcium. Despite a high calcium concentration within the granules, only very small single scattered calcium precipitates could be detected between these structures as compared with the amount of calcium precipitates attached to the plasma membrane or located within the cell nuclei. The nearly complete absence of precipitates within the melanin granules after the application of antimonate suggests differences in calcium binding and mobility involved in various physiological processes of ion balance regulation within the stria vascularis.

Animals↗
PubMed1998

Immunoelectron microscopic localization of nitric oxide synthase III in the guinea pig organ of Corti.

Nitric oxide synthase III (NOS III) was identified in the guinea pig cochlea on an ultrastructural level using a post-embedding immunolabeling procedure. Ultrathin sections of London Resin (LR) White-embedded specimens were incubated with various concentrations of a commercially available antibody to NOS III and the immunoreactivity visualized by a gold-labeled secondary antibody. Analysis of ultrathin sections of the organ of Corti in the second turn of the cochlea showed that NOS III could be localized in the endothelial cells of the blood vessels under the basilar membrane, which was comparable to its location in similar cells types in various biological systems. Besides this, NOS III was also found in the cytoplasm and in the nuclei of inner and outer hair cells. Immunoreactivity was not distributed homogeneously within receptor cells. Numerous gold particles could be identified at the border of the cuticular plates, in the middle parts of the stereocilia and in the cytoplasm. Gold-labeled anti-NOS III antibodies in these sites were seen mostly on the cytoplasmic side of the submembranous cisterns in the vicinity of mitochondria and in the central parts of the hair cells, whereas the cisterns were nearly free from any immunoreactivity. NOS III was also detected in the efferent and afferent nerve endings that were located at the basal and basolateral side of the outer hair cells. Some immunoreactivity was visible in different nerve fibers of the inner and outer spiral tunnels. Besides this, gold-labeled antibodies were also present in the cuticular plate of inner and outer pillar cells, in the cytoskeletal elements located in the apical parts of Deiters cells, forming the lamina reticularis, and in the cytoskeletal-containing region of the cytoplasm of those Deiters cells located at the basal side of the outer hair cells. The role of the NOS III immunoreactivity identified in the organ of Corti was consistent with respect to hair cell and tissue modulation.

Animals↗
PubMed1998

Possible Ca2+-dependent mechanism of apical outer hair cell modulation within the cochlea of the guinea pig.

Calcium ions were precipitated with potassium antimonate after injection of the inorganic calcium channel blocker MnCl2 or the inorganic potassium channel blockers BaCl2 or CsCl into the perilymph of the scala vestibuli of the guinea pig. The spatial distribution of the formed histochemical reaction products within the organ of Corti was studied by energy-filtering transmission-electron microscopy. Compared with untreated control ears, the number of the formed precipitates drastically increased at the extracellular side of the lamina reticularis after application of the various inorganic channel blockers. The apical side of the outer hair cells and the intervening Deiter cells were covered by a thick layer of calcium precipitates, whereas the number of histochemical reaction products was clearly reduced in the nearby acellular tectorial membrane. The high calcium content within the formed reaction products at the lamina reticularis could be demonstrated by elemental mapping and by electron energy-loss spectroscopy. To ascertain the alterations in the amounts of the calcium precipitates within the tectorial membrane after application of the various inorganic channel blockers, the precipitate densities were determined semiquantitatively by an image processing system and the values obtained compared with those of untreated control specimens. The observed histochemical results are in good agreement with published electrophysiological findings concerning the spatial distribution of ion channels located at the apical outer hair cell membrane. The detected alterations in the spatial distribution of calcium precipitates might correspond to calcium-dependent processes involved in outer hair cell modulation.

Animals↗
PubMed1998

The supracondylar approach to the jugular tubercle and hypoglossal canal.

BACKGROUND: Circumscribed lesions of the hypoglossal canal and of the jugular tubercle still remain a surgical challenge. So far, transpetrosal, transcondylar suboccipital, and extreme lateral approaches have been used to access this region. These surgical procedures bear a high risk for neurological deficits. Therefore, we introduce a new minimally invasive extradural approach to the hypoglossal canal that also allows access to the lateral aspects of the jugular tubercle. METHODS: After a paramedian retromastoid skin incision, a basal suboccipital craniectomy lateral to the foramen magnum toward the jugular tubercle is performed. With this approach the occipital condyle and the lateral osseous circumference of the foramen magnum are preserved. Drilling extradurally, the dorsal parts of the jugular tubercle are removed. The exposure is extended downward to the posterior margins of the hypoglossal canal and laterally to the jugular bulb, enabling a minimally invasive exposure of the hypoglossal canal, the lateral aspects of the jugular tubercle, and medial aspects of the jugular bulb. RESULTS: Using this supracondylar approach, surgical interventions were performed in three patients suffering from a hypoglossal neurinoma, a cholesterol granuloma extending into the jugular tubercle, and a cyst of the hypoglossal canal, respectively. No additional postoperative neurological deficits were seen. CONCLUSIONS: The supracondylar approach seems to be useful to gain access to benign lesions of the hypoglossal canal and of the jugular tubercle to decompress tumors or cysts. In contrast to previously reported techniques this approach has a low risk of morbidity. The surgical field, however, is restricted laterally by the jugular bulb, medially and basally by the residual occipital condyle and dorsally by the dura. Therefore, this approach is useful to remove small lesions or to perform extended biopsies. Radical removal of large tumors seems to be problematic using this approach.

Adult↗
PubMed1998

Microsurgical treatment of midfacial tumours involving the skull base.

Various approaches to the base of the skull for the treatment of cranial base tumours are described in detail. Advantages and disadvantages of the particular approaches are discussed. This clinical experience is based on 303 neoplasms involving the base of the skull, operated on by the authors. Retrospective survival studies are presented and a review of the literature on the subject is discussed. Utilizing microsurgical techniques the 2-, 3- and 5-year survival rates were significantly improved. The functional and aesthetic outcomes were also dramatically superior compared with standard ablative procedures. Reconstructive postoperative strategies are suggested.

Carcinoma, Adenoid Cystic↗
PubMed1998

[Arachnoid cyst of the sphenoid sinus].

BACKGROUND: Arachnoid cysts of the paranasal sinus are rare. They have not been described yet in the sphenoid sinus. PATIENT AND METHOD: Microscopic-endoscopic endonasal surgery of the sphenoid sinus was performed on a 34-year-old female with a history of chronic headaches and a suspected mucocele of the sphenoid sinus in computed tomography (CT) and magnetic resonance imaging (MRI) studies. An extended arachnoid cyst was found in the enlarged sphenoid sinus, which was obliterated with collagen, fibrin glue, and abdominal fat. RESULTS: There were no complications after the operation, and 12 months later the patient is still free of symptoms. CONCLUSION: Arachnoidal cysts present in CT and MRI as fluid dense lesions that can imitate a mucocele.

Adult↗
PubMed1998

[Biology and growth velocity of tumors of the globus jugulotympanicum and glomus caroticum].

BACKGROUND: Paragangliomas (glomus tumors) of the head and neck are rare tumors, arising from the paragangliomatous tissue either of the carotid region or the jugular or the tympanic region. This study was conducted to investigate the possible differences in the tumor biology of these lesions depending on their site of origin. METHODS: Nineteen specimens (10 jugulotympanic and 9 carotid glomus tumors) were investigated by quantitative DNA measurements and immunohistochemical assessment of proliferation markers (PCNA, Ki67), oncogenes (p53, nm23), different cell surface antigenes (CD44 4/5 and 6, CD54, CD106), and bcl 2 as a marker for apoptosis. RESULTS: Depending on the location of the tumors these measurements revealed significant differences in tumor biology with higher proliferation scores and a higher number of aneuploid tumors in those of the carotid region, suggesting a more aggressive behavior compared to those of the jugulotympanic region. CONCLUSIONS: The results also indicate a difference between the two groups in the risk of developing metastases or recurrent disease. They generally help to enhance our understanding of the biology of paragangliomas of the head and neck.

Adolescent↗
PubMed1998

Comparison of olfactory function in patients with seasonal and perennial allergic rhinitis.

Hyposmia is a common symptom in allergic rhinitis. However, little is known about differences in the olfactory function of patients with seasonal or perennial allergy. A prospective controlled study was performed on 28 patients with allergic rhinitis to grass pollen and on 47 patients with allergic rhinitis to mites. Sixty-six healthy volunteers served as a control. Olfactory function was evaluated by a modified Connecticut Chemosensory Clinical Research Center testing procedure for threshold, identification, and discrimination. The grass pollen-allergic patients were tested preseasonally and after 3 weeks of intraseasonal grass pollen exposure; the mite-allergic patients and the volunteers were tested once. In the mite allergics, olfactory threshold, identification, and discrimination tests were significantly worse than in the volunteers (all P < 0.0001). In the grass pollen allergics, the results in olfactory identification and discrimination tests were not different from the controls if tested out of the season (both P > 0.05). However, in threshold testing (P = 0.0139), the results were worse. Intraseasonally, the grass pollen allergics showed a significant decrease in threshold, identification (both P < 0.0001), and discrimination testing (P = 0.0029). If the intraseasonal pollen allergics were compared to the mite allergics, they showed better results in identification (P = 0.0087) and threshold (P < 0.0001) tests, but worse results in discrimination testing (P = 0.0002). Therefore, the different kind of allergen exposure seems to result in a different pattern of allergic olfactory dysfunction.

Adolescent↗
PubMed1998

Tree-pollen allergy is efficiently treated by short-term immunotherapy (STI) with seven preseasonal injections of molecular standardized allergens.

The efficacy and tolerance of short-term immunotherapy (STI) by seven preseasonal injections of tree-pollen allergens (ALK7 Frühblühermischung) was investigated in a double-blind, placebo-controlled, multicenter study with 111 rhinoconjunctivitis patients. Nasal and bronchial symptoms simultaneously analyzed, and nasal symptoms as a single end point, but not the overall score of nasal, bronchial, and conjunctival symptoms, showed a significantly lower increase with STI during birch-pollen exposure (both P=0.033, n=105, Mann-Whitney U-test). However, a selective analysis with patients from centers with high recruitment figures (n> or =10 patients, n=29 STI, n=32 placebo) showed a significantly lower increase of nasal, bronchial, and overall symptom score (STI 11.0 vs placebo 18.0, P=0.001, U-test). STI had equidirected effects on conjunctival, nasal, and bronchial symptoms analyzed as multiple end points, although conjunctival symptoms were not significantly different as a single end point. The seasonal increase in drug use was reduced by 62% in the STI group compared with placebo (P=0.032, t-test). Specific IgG4 increased only after STI (P<0.001); IgE was not significantly different. Eosinophil cationic protein remained unchanged with STI, but significantly increased with placebo in the pollen season (P=0.003). STI was well tolerated. In conclusion, STI was shown to be efficacious and safe for the treatment of patients with tree-pollen rhinoconjunctivitis.

Adolescent↗
PubMed1997

Characterization of nitric oxide synthase isoforms expressed in different structures of the guinea pig cochlea.

Nitric oxide synthase (NOS) activity and NADPH diaphorase staining has previously been reported in mammalian cochlea. Here we demonstrate immunoreactivity for neuronal-type NOS I and endothelial-type NOS III in the cochlea of the guinea pig. NOS I immunoreactivity was seen in inner and outer hair cells, and spiral ganglion cells. Staining for NOS I was also shown in basal and intermediate cells of the stria vascularis, spiral ligament cells, and the media of vessels near the modiolus. An antibody to NOS III stained primarily vascular endothelial cells. Some NOS III immunoreactivity was also detected in spiral ganglion cells. An antibody to the inducible-type NOS II did not stain any structure of the guinea pig cochlea, suggesting that this isoform is not expressed under physiological conditions. Nitric oxide produced by NOS I and/or NOS III may act as a neuromodulator in the organ of Corti and could also play a role as a regulator of cochlear blood flow.

Animals↗
PubMed1997

Alteration of loosely bound calcium in the guinea pig organ of Corti after treatment with diltiazem as calcium channel blocker.

After oral administration of the organic calcium channel blocker diltiazem to guinea pigs for 7 days, calcium ions were precipitated with potassium antimonate in the cochleae. The spatial distribution of the precipitates was studied by energy-filtering transmission electron microscopy and the amount of the ultrastructural reaction products formed was determined semiquantitatively by an image processing system. Compared with untreated control ears, the number of the formed precipitates was reduced drastically in the inner hair cells after diltiazem treatment. In addition, electron microscopic analysis revealed that the number of calcium precipitates attached at the basolateral membrane of the outer hair cells was clearly reduced when compared with untreated control specimens. A large number of histochemical reaction products could be identified in the basilar membrane and were also observed in the untreated control specimens. The spatial distribution of the calcium precipitates in the lamina reticularis was not affected by diltiazem treatment and calcium precipitates could be identified within different cell membranes. The techniques used was considered to be helpful for identifying calcium channels ultrastructurally in intact undissected tissues and to support light microscopic analyses and patch-clamp electrophysiological measurements.

Administration, Oral↗
PubMed1997

Electron microscopic localization of nitric oxide I synthase in the organ of Corti of the guinea pig.

Nitric oxide synthase (NOS) activity has been detected previously in the mammalian cochlea at a light microscopic level. Here we present results of electron microscopic analysis for post-embedding immunoreactivity of neural-type NOS I in the cochlea of the guinea pig. Strong enzyme immunoreactivity was identified in the cytoplasm of inner and outer hair cells. Gold-labeled NOS I antibodies were mainly located in electron-dense areas of the cytoplasm, whereas electron-lucent regions of the receptor cells were nearly free from any immunoreactivity. In both types of hair cells anti-NOS I antibodies were also visible in the cuticular plates, hair bundles and nuclei. Further ultrastructural analysis revealed that the submembranous cisternae of the outer hair cells were nearly free from any reaction product, demonstrating that the whole cytoplasm of this hair cell was not immunoreactive. Other NOS I immunoreactivity was identified in the cuticular plates of the inner and outer pillar cells and in the cytoskeletal elements located in the apical parts of Deiter cells, forming the lamina reticularis or in cytoskeletal-containing regions in basal Deiter cells. Anti-NOS antibodies were visible in the nuclei of various cell types. Our findings suggest that nitric oxide produced by NO I synthase in the organ of Corti may act as a modulator of hair cell physiology during the processes of signal transduction with frequency selectivity.

Animals↗
PubMed1997

[Endoscope-microscope combination (ENDO-OPMI) for endonasal paranasal sinus surgery].

The development of modern endonasal sinus surgery is fundamentally based on the introduction of optical instrumentation. Endoscopes and microscopes are commonly used in such surgery. We tested a new combination of a stereoscopic single-channel endoscope with an operating microscope (ENDO-OPMI) for endonasal sinus surgery. This combination of the endoscope and microscope are connected in a way that results in a self-carried stereo-endoscope. To date, the ENDO-OPMI has been evaluated in cadaver studies and 7 cases of endonasal sinus surgery for chronic sinusitis. The trial was used to evaluate the clinical use of the current system and its possibilities for future developments. The ENDO-OPMI was demonstrated to be principally well-suited for endonasal sinus surgery. However, the current technical shortcomings make further developments necessary. Once these are implemented, the system should be superior to the use of an endoscope or microscope alone in endonasal surgery.

Chronic Disease↗