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Biomedical subjects

W Mann

Publications and source records attributed to W Mann.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Effect of contralateral stimulation on otoacoustic evoked emissions in acute deafness].

23 patients with unilateral hearing loss and presence of TEOAE on both ears were examined with regard to the association between contralateral acoustic stimulation and evoked otoacoustic emissions. Contralateral white noise of 40 dB HL, 50 dB HL and 60 dB HL decreases the amplitude of TEOAE both at the ear with and without hearing loss. In comparison with a group of subjects with normal hearing, the decrease in the amplitude of TEOAE was less in the group of patients with hearing loss. Two paradoxical cases were found with an increase in the TEOAE amplitude in the ear with hearing loss during contralateral stimulation. It is assumed that impairment of the efferent synapses on the outer hair cells or of the decussated efferent nerve fibres at the floor of the fourth ventricle contributes to the pathogenesis of hearing loss. Impairment of the efferent system at brainstem level can explain the lower decrease in the amplitude both in the diseased ear and the normal ear. The behaviour of the normal ear during stimulation of the diseased ear can also be caused by disturbance of the afferent system.

Acoustic Stimulation↗
PubMed1994

[Rare differential diagnosis in "vertigo" symptoms].

The diagnosis of vestibulocochlear nerve and statoacoustic organ lesions is based on the symptoms vertigo, hearing loss and tinnitus. The most common diseases are vestibular neuronitis, Ménière's disease, benign positional vertigo and sudden hearing loss. 6 patients are presented, complaining of at least one of the symptoms vertigo, hearing loss or tinnitus. They were suspected of suffering from a peripheral audiovestibular disease when admitted to the clinic, but all of them revealed other pathologies. A careful history and step-wise otoneurologic diagnostics including clinical examination, otoneurologic testing, audiologic tests, electronystagmography, acoustic evoked potentials and imaging techniques finally resulted in the correct diagnosis.

Adult↗
PubMed1994

[Intraoperative monitoring of motor cranial nerves in operations of the neck and cranial base].

Intraoperative monitoring of cranial nerves is performed to minimize postoperative cranial nerve dysfunction. We performed electrophysiological monitoring of motor cranial nerves with a NIM 2 unit from Xomed Treace and a patient multiplexer developed in our clinic. This multiplexer allows simultaneous monitoring of 4 cranial nerves and is additionally equipped with a bipolar stimulation mode. This intraoperative monitoring was employed during 102 skull base operations. Of these 102 operations, 44 were acoustic neuroma removals by translabyrinthine approach and 36 by a middle fossa approach. Various operations including removal of tumours of the jugular foramen and the infratemporal fossa were performed in the remaining 22 patients. The facial nerve, being the most frequently monitored nerve, was evaluated both pre- and intraoperatively. Electrophysiologic data were evaluated with respect to their predictive value for postoperative facial nerve function. The relative per cent decrease in amplitude of the EMG after resection compared to that observed before resection seems to be of some predictive value for postoperative facial nerve function. A 50-60% decrease or more is associated with an increase in the House classification. Intraoperative monitoring is a useful tool in skull base surgery allowing for safer and faster identification of motor nerves in pathologic anatomic conditions. It allows the surgeon a degree of comfort by providing immediate information regarding the status of the nerve. It may also improve post-operative nerve function and shorten operating time. Additionally, neuromonitoring provides some information about expected postoperative facial nerve function.

Cranial Nerves↗
PubMed1994

The state of the art of ultrasonography in the head and neck.

When considering patient comfort, length of testing, availability, the increased diagnostic capabilities and relative cost, we believe that ultrasonography is an important addition to the diagnostic tests currently used in otolaryngology. It is a noninvasive method with high sensitivity. When one includes the techniques of ultrasound-guided fine-needle aspiration, cutting biopsy and colour-coded duplex sonography, the specificity is further augmented and is superbly suited for demonstrating, detecting and excluding pathologies in the head and neck region. It will increase the accuracy of preoperative staging of patients with head and neck squamous cell cancer. It is even possible that it may change the indications for therapeutic and elective neck treatment. In addition it is valuable during the follow-up of patients treated with radiation or/and chemotherapy. In many situations, ultrasonography is superior to CT or MRI because it is a dynamic imaging technique with the possibility of simultaneous palpation of the lesion. It does not force the surgeon to reconstruct anatomy from computer generated slices which leave gaps that may miss disease and it can detect major vessel invasion by tumour.

Biopsy, Needle↗
PubMed1993

Papanicolaou smear screening augmented by a magnified chemiluminescent exam.

OBJECTIVES: Since the adequacy of screening for cervical cancer and pre-cancer with Papanicolaou smear alone has been questioned, a number of adjunctive tests have been evaluated. This study evaluated whether a magnified chemiluminescent visual screening exam can improve cervical screening when performed coincident with cytologic sampling. METHODS: Patients were evaluated using the Papanicolaou smear, magnified chemiluminescent visual exam (MCE) and colposcopy at 10 study centers. Screening with either Papanicolaou smear alone or in combination with MCE (Pap and MCE), was evaluated using colposcopy directed biopsy as the highest diagnostic standard. RESULTS: The Papanicolaou smear alone detected 9/29 (31%) of women with significant pathology (cervical neoplasia) on biopsy, whereas the combination of the Pap and MCE detected 24/29 (83%) of the women (P < 0.001). Patients in whom both tests results were negative (negative Pap and MCE) were extremely unlikely to harbor significant pathology (1% of those screened). Pap and MCE was especially helpful in the detection of low grade cervical lesions when compared with the Papanicolaou smear alone. CONCLUSIONS: These data indicate that MCE enhances the sensitivity of cervical screening. MCE appears to be particularly useful as a triage instrument in women with otherwise negative Papanicolaou smears. Further studies of cost effectiveness of this combined screening protocol using non-colposcopists is warranted.

Adolescent↗
PubMed1993

[Soft laser therapy in combination with tebonin i.v. in tinnitus].

28 patients were treated with soft-laser therapy. Two-thirds of them had suffered from tinnitus for more than six months and had undergone different therapies before. Each patient was treated twelve times, treatment lasting ten minutes. Before therapy six ml of Tebonin were given i.v. Four minutes later, the laser was positioned at a distance of one centimetre from the patients' mastoid. The laser beam was directed two fingers above the mastoid tip aiming at the lateral wall of the contralateral orbit. Before and three weeks after treatment each patient underwent pure tone audiometry and determination of the tinnitus intensity. Patients were asked to score symptoms before and three weeks after therapy. Hearing levels before and after soft-laser therapy did not show any statistic difference. Three weeks after the last treatment, twenty patients denied any change in tinnitus. Two patients felt an improvement of tinnitus and one patient had recovered completely. Five patients remained undecided about the outcome of therapy. To sum up, according to our results, the trial so far failed to show clear benefits of soft-laser therapy for patients suffering from chronic tinnitus.

Adult↗
PubMed1993

[Sigmoid sinus thrombosis, a therapeutic problem].

Thrombosis of the sigmoid sinus is a relatively uncommon illness. It may present in a septic or bland form, and the latter is more or less asymptomatic. Angiography, computerised tomography and magnetic resonance imaging are all at our disposal for diagnosis of both types of thrombosis, and proper diagnosis of the specific form of sinus thrombosis will determine the required therapy. Between 1985 and 1990 six patients with sigmoid sinus thrombosis were treated at the Departments of ENT, Johannes Gutenberg University, Mainz and Albert Ludwig University, Freiburg, Germany, on an in-patient basis. By means of these cases we present our experience with this uncommon condition.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Color duplex ultrasound measurement of lymph node perfusion: a contribution to diagnosis of cervical metastasis].

The objective of this study was to find additional sonomorphological criteria for determining the status of enlarged lymph nodes. By using colour-coded duplex sonography the perfusion of 63 lymph nodes in the neck was analysed. The status was confirmed either histologically or clinically (29 metastases from squamous cell carcinomas and 34 acute or chronic inflammatory nodal diseases). A quantitative evaluation of the pulsatility measured in 51 lymph nodes by computing the Pourcelot-Ratio and the Mean Pulsatility Index yielded significant differences between the two groups. By definition of a limiting value of the Pourcelot-Ratio (0.75) for the prediction of benignity, the specificity and the accuracy in screening for metastases were improved as compared to clinical examination and B-mode sonography. Additional criteria of dignity were found by qualitative evaluation of nodal perfusion patterns (presence and distribution of perfusion, partial loss of perfusion). The use of colour-coded duplex sonography in nodal disease of the neck provides an improvement of early and noninvasive diagnosis of regional metastatic involvement.

Blood Flow Velocity↗
PubMed1993

[Unusual course of otobasal fractures with liquorrhea].

In the literature the persistence of cerebrospinal Liquorrhea after temporal bone fractures is a rare event. Between 1989 and 1992 four cases of temporal bone fractures with dural involvement were operated at the University ENT Department Mainz. These temporal bone fractures showed delayed or persistent symptoms of dural lacerations between three and sixty months after head injury. During operation we found larger bone-dura defects (1-1.5 cm in diameter) and brain herniations in all cases. Strohm stated that only in rare cases a temporal bone fracture produced a larger gap in the tegmen tympani or antri. Therefore, we assumed that in our cases such larger bone-dura defects were caused by a gradual widening of the bony gap by a local elevation of intracranial pressure. Ferguson described this phenomenon in cases with spontaneous cerebrospinal Liquorrhea. Our cases showed that the cessation of cerebrospinal Liquorrhea is not a reliable sign of a healed dura defect. Therefore we propose that temporal bone fractures should be controlled closely in the first twelve months after trauma even if the dura defect seems to close spontaneously.

Adolescent↗
PubMed1993

Morphologic damage and changes of intracellular calcium-binding sites after acute noise trauma in the organ of Corti of the guinea pig.

In guinea pigs, an acute acoustic trauma was created by 6 consecutive gunshots. The sound pressure at the ear drum was 156 +/- 4 dB, the frequency maximum was between 4 and 6 kHz. Sixty hours after the noise trauma, the animals were decapitated, and the cochleae were prepared for microscopic analysis of the resulting trauma to the organ of Corti. During the process of fixation, the potassium-pyroantimonate precipitation reaction was performed to localize calcium-binding sites. The pattern of cell morphology and the distribution of calcium-binding sites was compared to that of normal control animals. Morphologic changes of the cells in the organ of Corti correlated with changes of the cellular calcium distribution, indicating the crucial role of calcium in cell damage and necrosis after acute noise trauma.

Animals↗
PubMed1993

[Use of a Ca(++) antagonist in noise-induced hearing loss in animal experiment].

Hearing thresholds at 1-2-4-6 and 8 kHz were determined by brainstem evoked response audiometry (BERA) in 24 guinea pigs. The animals were then divided into 6 groups. Group 1 (controls) received no drugs and were not exposed to noise. Group 2 were given 15 mg/24 h/kg diltiazem s.c. for 13 days. Group 4 was exposed to the same noise as group 3 but was also treated with diltiazem 15 mg/kg/24 h from three days before noise exposure until the end of the experiment. Group 5 was exposed to a 110 dB SPL broad-band noise for 3 h daily for 10 days. Group 6 was exposed to the same noise as group 5 and was treated with diltiazem 15 mg/kg/24 h from three days before noise exposure until the end of the experiment. After the last noise exposure hearing thresholds were determined again by BERA and were found to be unchanged in those animals treated with the drug alone and the controls. In those groups with drug administration and noise exposure hearing loss was less than in the animals exposed to noise alone. This difference was more pronounced in the 90 dB groups than in the 110 dB groups.

Acoustic Stimulation↗
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↗