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Biomedical subjects

W Mann

Publications and source records attributed to W Mann.

At least 19 recordsLinked to original sources
PubMed1992

Immunoassay of type IV collagenase/gelatinase (MMP-2) in human plasma.

We have developed a sensitive and specific sandwich type enzyme-linked immunosorbent assay (ELISA) to detect type IV collagenase (MMP-2) in human plasma which employs the combination of affinity purified rabbit polyclonal antibodies and mouse monoclonal antibodies to human MMP-2. The MMP-2 ELISA detects latent and activated MMP-2, MMP-2 complexed with TIMP and MMP-2 complexed with alpha 2 macroglobulin (65% efficiency). To determine whether physiologic conditions associated with increased connective tissue turnover are accompanied by increased MMP-2 levels in plasma, we compared enzyme levels in pregnant and nonpregnant women. Plasma MMP-2 (mean +/- standard deviation) was significantly increased (p less than 0.05) in the second half of pregnancy (650 +/- 312) as compared to early pregnancy (356 +/- 139) or the nonpregnant state (387 +/- 193). As a result of the linkage between type IV collagenase production by cancer cells and the metastatic phenotype, the assay of MMP-2 in plasma is of potential clinical value in cancer.

Antibodies, Monoclonal↗
PubMed1992

Histochemical localization of calcium ATPase in the cochlea of the guinea pig.

The activity of Ca(2+)-ATPase in the inner ear of the guinea pig was studied ultracytochemically by the lead citrate reaction. The electron-dense reaction products as an expression of Ca(2+)-ATPase activity were localized in endolymphatic cells of Reissner's membrane, in outer and inner hair cells and in some supporting cells. The main finding was the difference in the localization of Ca(2+)-ATPase in outer and inner hair cells. In the latter cells the activity sites were mainly intracellular and in apical membrane specializations, whereas in the outer hair cells the enzyme was localized in the apical membrane specializations and the basolateral plasma membrane.

Animals↗
PubMed1992

Human papillomavirus types and cervical squamous intraepithelial lesions that recur after cold-knife conization.

The purpose of this study was to analyze the HPV types and histological margins of cervical squamous intraepithelial lesions (SILs) treated by cold-knife conization and to correlate this with recurrent disease. Of 203 cone biopsies done for SILs primarily because the entire lesion could not be visualized at colposcopy, follow-up information was available for 85 cases. Of these 85 cases, biopsy-proven recurrences were documented for 10 (12%) women. In the SILs which recurred after conization, the lesion was noted on the surgical margin in 7/10 (70%) cases. In contrast, SILs that did not recur after cold-knife conization were detected on the surgical margin in only 12% of cases. In 7 of the recurrences, the HPV type detected in the pretreatment SIL was the same as that detected in the SIL that occurred after conization. In the other 3 recurrences, one of either the primary or recurrent SILs was HPV positive and the other corresponding lesion HPV negative. It is concluded that detection of a SIL on the surgical margin is a marker for recurrent disease and that recurrences are often associated with the same HPV type as that noted in the pretreatment SIL.

Biopsy↗
PubMed1992

[Changes in otoacoustic emissions with simultaneous acoustic stimulation of the contralateral ear in normal probands and patients with unilateral acoustic neurinoma].

Contralateral white noise alters the amplitude of transitory evoked otoacoustic emissions (TEOAE). 27 students between 20 and 28 years of age with no history of ear disease or dizziness were tested for normal hearing by pure tone audiogram. OAE evoked by nonlinear stimuli were measured with and without contralateral stimulation by 40, 50 and 60 dB white noise. The contralateral stimulation resulted in a statistically significant diminution of the amplitude of the TEOAE under contralateral acoustic stimulation. This diminution is probably caused by the effect of the crossed bundle of the efferent innervation on the outer hair cells resulting in altered vibratory properties of the basilar membrane. In patients with unilateral acoustic neuroma and measurable TEOAE a diminution of the amplitude of the TEOAE under contralateral sound stimulation was not found. The testing can easily be performed with the routine measurement of TEOAE. It could be useful in the diagnostic of lesions of the cerebello pontine angle and the brain stem.

Acoustic Stimulation↗
PubMed1992

Localization of Ca(2+)-stores and tissue compartments with a Ca(2+)-binding capacity in the organ of Corti of the guinea-pig by electron energy-loss spectroscopy.

The addition of 10 mM CaCl2 to glutaraldehyde fixative leads to the formation of small electron-dense deposits in the organ of Corti of the guinea-pig. These precipitates are mainly attached to cell membranes in contact with different extracellular lymphatic fluids. A higher number of precipitates is localized in the acellular parts of tectorial and basilar membrane. Electron energy-loss spectroscopy (EELS) was used to determine the elemental composition of the deposits formed. The spectra showed a prominent signal at the Ca2+ L2,3 ionization edge. Oxygen could also be detected in all the precipitates analysed. EELS analysis of mitochondria of the inner and outer hair cells after conventional fixation (glutaraldehyde followed by post-fixation in OsO4) revealed a small but significant calcium signal.

Animals↗
PubMed1992

Quantitative DNA measurements in malignant and benign lesions of the upper aerodigestive tract.

Thirty-six patients underwent biopsy of clinically suspicious lesions of the mucosa of the upper aerodigestive tract. The biopsy material was evaluated histologically and cytologic smears out of the same lesion underwent quantitative DNA analysis using a numerical index derived from the single cell DNA content. In 30 patients, histologically diagnosed squamous cell cancer was confirmed by DNA analysis with the malignancy grade correlating with the morphologic differentiation of the tumor. Six lesions were histologically benign: i.e. dysplasia (n = 3), hyperplasia (n = 2) and chronic inflammation (n = 1). DNA analysis confirmed the benign nature in 4 cases, but in 2 cases of dysplasia, a diagnosis of malignancy was made. From these results, there appears to be an excellent correlation between DNA analysis and the histologic diagnosis of malignancy. It remains to be proven if this technique of DNA analysis will prove to be a more accurate determinant of malignant potential in premalignant conditions and a method to determine aggressiveness of behavior. An added advantage is that this technique can be performed on cytologic smears, without the need for incisional biopsy.

Adult↗
PubMed1992

[Changes in transitory evoked otoacoustic emissions in chemotherapy with cisplatin and 5FU].

The aim of this study was to detect changes of transient evoked otoacoustic emissions (TEOAE) during chemotherapy with cisplatin and fluorouracil (5FU). A review of the literature reveals that the incidence of cisplatin ototoxicity varies from 9% to 50%; this variation is due to differences in doses, duration of administration, to the criteria for ototoxicity and on audiological methods. Three cycles of chemotherapy (1000 mg/m2 5FU from day 1 to 5 and 100 mg/m2 cisplatin on day 1) were given to 12 patients; the OAE were measured before chemotherapy and after each administration. In 86% of the ears measured we found changes in the TEOAE; the mean values for the amplitude of the TEOAE decreased about 13% after the end of the chemotherapy. Pure tone thresholds were reduced in almost 50% of the measured ears. The decrease of amplitude of TEOAE is an early sign of an ototoxic secondary effect, probably due to damage to the outer hair cells. TEOAE is a sensitive method for detecting ototoxicity in cisplatin-treated patients and more reliable than pure-tone audiometry or evoked acoustic potentials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Calcium-binding sites in the inner ear after pure-tone stimulation.

Five guinea pigs were exposed to an interrupted 90 dB SPL pure tone of 3.2 kHz for a total application time of 5 min. Following sound application all animals were decapitated and the cochleae were removed. After that, calcium-binding sites were located by the potassium pyroantimonate precipitation method. Another three animals served as control animals and did not receive the sound treatment. Findings confirmed previous studies showing the spatial arrangements of precipitate rich regions in the inner ear's two acellular structures (the basilar membrane and tectorial membrane) and the two cellular structures (the inner hair cells and Huschke's teeth). By using semiquantitative evaluation we found a relative diminution of precipitable calcium in inner hair cells and in Huschke's teeth of sound-exposed animals when compared to untreated animals.

Acoustic Stimulation↗
PubMed1991

[Radical versus modified neck dissection. Cancer-related and functional viewpoints].

In a retrospective study 256 cases with curative or prophylactic neck dissection were evaluated with regard to neck recurrence and survival. In 173 cases the spinal accessory nerve had been preserved, in the remaining 86 cases it had been sacrificed. The results demonstrate that preservation of the accessory nerve has no influence on the regional recurrence rate and on survival if preservation of the nerve is possible without compromising the radicality of the neck dissection and if the patient is subjected to post-operative radiation.

Carcinoma, Squamous Cell↗
PubMed1991

[Functional deficits of caudal cranial nerves after surgery of tumors in the foramen jugulare. A long-term follow-up study].

Jugular foramen tumors involve a critical area of the skull base. Usually they are characterized by palsy of the ninth, tenth, and eleventh cranial nerves. Depending on the extent of the tumor there are various approaches to the skull base and various surgical strategies to preserve the cranial nerves. The study is based on 31 patients who were operated on between 1982 and 1989 at the University ENT and Neurosurgery Departments in Freiburg and Mainz. The neurological findings were analyzed on admission, on discharge, and in the follow-up. While there was partial or complete dysfunction of the lower cranial nerves on discharge, long-term compensation was excellent. All patients were able to breath normally and maintain their weight by oral diet. Rerouting of the facial nerve endangers its postoperative function. Nevertheless, the long-term follow-up demonstrated excellent recovery and good functional and cosmetic results.

Adolescent↗
PubMed1991

Progress in electron microscopic diagnostics: semi-quantitative determination of precipitable calcium in different cell types of the organ of Corti in the guinea-pig.

Potassium antimonate was used to precipitate calcium in the cochlea of the guinea-pig. The distribution of the calcium antimonate precipitates was analysed by electron microscopy. The precipitate density was determined in different cell types in the organ of Corti by counting the number of calcium binding sites in a 10-micron 2 area. The size of the precipitates varied considerably, and thus the relative amount of the precipitable calcium was estimated only semi-quantitatively. As the prominent carbon signal is superimposed over the nearby small Ca(2+)-edge signals, the combined signal of the antimony M4,5-edge and the oxygen K-edge of the calcium antimonate salt formed was chosen for the semi-quantitative estimation. Images of the inelastically scattered electrons of the precipitates at delta E = 570 eV were recorded by electron spectroscopic imaging. The area covered by the calcium precipitates within a given cell type was determined in different ultrathin sections of the same organ of Corti by an image processing system.

Animals↗
PubMed1991

[Microsurgical endonasal decompression of the optic nerve].

A new endonasal microsurgical technique for decompression after traumatic optic neuropathy is presented. Compared to the external transethmoidal, the transfrontal or the pterional approach, the main benefit of this method is the superb stereoscopic vision of the medial aspect of the optic canal. The nerve is approached from a 60 degree to 90 degree angle and continuous suction irrigation allows for safe removal of the bony shell. This surgery is done via the endonasal route and therefore has fewer serious complications compared to intracranial, extradural or intradural approaches. Additional trauma due to retraction of the brain is avoided. The anterior ethmoidal cells and the nasofrontal duct remain untouched, avoiding late mucocele formation.

Endoscopy↗
PubMed1991

Nasal surgery in German speaking countries around the turn of the century.

The historical review of submucous septal surgery includes the German pioneers Hartmann (1882) and Petersen (1883), Krieg (1886) and Killian (1899) who finally refined this operation. Besides his technical notes and the development of new instruments Killian defined indications and contraindications for this type of surgery which are considered valid even today.

Austria↗
PubMed1990

Ultrastructural localization of Ca2(+)-binding sites in the middle ear mucosa of the rat.

Cations were precipitated with potassium-pyroantimonate in the middle ear mucosa of the rat and the distribution of the formed precipitates was studied by electron microscopy. The precipitate density in various cells of the different epithelia of the middle ear mucosa was determined on electron micrographs by counting the number of precipitates per unit area. Electron spectroscopic imaging was also performed to obtain information about the spatial distribution of the precipitates and their elemental composition.

Animals↗