摘要:

The behaviour of evoked otoacoustic emission (EOAE) has been studied in normally hearing adults under the conventional forward masking paradigm. The clicks and tone pips served as signals, and the noise bursts were used as maskers. At noise burst levels, defined as psychoacoustic masking thresholds of signals (postmasking threshold), attenuation of EOAEs was just noticeable but did not occur in all records. The EOAEs were not completely eliminated even at noise levels exceeding the post-masking threshold by 30 dB. Central or neural and peripheral or receptor mechanisms are suggested to be the constituents of the masking phenomenon. The receptor mechanism effectively joins the neural one at masker levels, well exceeding the thresholds of psychoacoustic masking. The increase in masker duration and decrease in interval between masker and signal seem to accentuate the neural mechanism. As a result, the difference between masker levels, leading to psychoacoustic masking of the signal and having marked attenuating effects upon the EOAEs, respectively, is increased.

ISSN:0301-1569    

DOI:10.1159/000276304

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The endolymphatic sac of chick embryos (from embryonic day 7 to 1-day-old chicks) was studied light- and electron-microscopically. At stage 30-31 (embryonic day 7-7.5), the epithelial cells of the endolymphatic sac were cuboidal to columnar in shape. Microvilli were relatively well developed. The intercellular space was wide. In the endolymphatic space of the endolymphatic sac, varying shapes and sizes of otoconia-like bodies were often observed. Intracytoplasmic phagosomes containing these bodies were rarely found. After stage 37 (embryonic day 11), otoconia-like bodies in the endolymphatic sac decreased in number and size. They were almost the same as the otoconia in the macular organs, ultrastructurally. These findings indicate that the endolymphatic sac of the chick embryos may possess the function of otoconial degradation and removal of calcium from otoconia.

ISSN:0301-1569    

DOI:10.1159/000276305

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The epithelial cells of the endolymphatic sac (ES) were studied in order to characterize their glycocalyx composition. Colloidal thorium and cationized ferritin were used as electron-dense markers to visualize the glycocalyx as well as the basement membrane. In addition, enzymatic digestions were performed to identify the reactive components of the glycocalyx responsible for colloidal thorium labeling. The results indicate that the glycocalyx of the ES epithelial lining is very rich in sialic acid. Furthermore, a marked polarity in glycocalyx reactivity is present between the apical and basolateral membranes, whereas difference in glycocalyx reactivity between the light and the dark cells are not obvious. We speculate that the specific composition and the apparent polarity of the ES epithelial cell glycocalyx are of importance to the equilibrium of electrolytes in the ES lumen.

ISSN:0301-1569    

DOI:10.1159/000276306

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The relation between iron deficiency (ID) and sudden sensorineural hearing loss (SSHL) was evaluated in the growing rats of three different experimental groups. Fourteen rats of 132 (10.61%) that were raised on a basic ID diet showed SSHL in varied extent, from moderate to profound. By contrast, none of 128 standard control and 126 anemic control rats that were fed with the final iron-supplemented diet showed any degree of SSHL. The main cochlear correlates of SSHL in ID rats were synchronous abnormalities of the iron-containing enzymatic activity in the whole cochlea, a significant reduction of spiral ganglion cells and a rapid involvement of stereocilia of the outer and inner hair cells. The results suggest that ID can play a major role in the pathogenesis of SSHL.

ISSN:0301-1569    

DOI:10.1159/000276307

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

This study was conducted to assess the usefulness and limitations of high-resolution CT for diagnosing the ossicular chain in the middle ear. The CT images in this study were obtained in as much detail as possible and 2 direction images. Preoperative CT findings of the ossicular chain were compared with operative findings in 26 patients with ossicular defects. Preoperative detection of the complete defect of the malleus head and the body and long process of the incus by high-resolution CT was possible in all cases, while detection of the defect of the manubrium of the malleus and superstructure of the stapes could be made in 33.3 and 60%, respectively. The defect of the incudostapedial joint (1 case) and partial defect of the stapes cms (2 cases) could not be diagnosed correctly by preoperative estimation.

ISSN:0301-1569    

DOI:10.1159/000276308

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

In 27 patients with Parkinson’s disease (PD), stapedial reflexes were measured using impedance audiometry and compared with those of 11 age-matched control subjects. The reflex threshold of PD patients was lower than that of control subjects. A prolongation of contraction time (C50) and relaxation time (D50) was revealed. Between patients with and without L-dopa, there was no significant difference for any reflex parameter. But, the D50 of patients without anticholinergic drugs was longer than that of patients with anticholinergic drugs. The authors could not find any relationship between the severity of PD and the reflex parameters. The authors assume that the prolongation of reflex parameters might be attributed to the hyperactivity of the indirect pathways of the stapedial refle

ISSN:0301-1569    

DOI:10.1159/000276309

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The in vivo tissue ablation characteristics of a pulsed holmium: YAG laser (λ = 1,980 nm) were studied. The laser energy was coupled onto nylon fibers 400 and 600 µm in core diameter. Laser incisions were made on white rats at different sites of the tongue and of the mucous membranes of the oral cavity. Power settings of 500 and 1,000 mJ/2.5-ms pulse at 5 pulses/s were used and the tissue responses examined by light microscopy. Wound healing was studied over a 6-week period. The results of this study are promising for future application of the holmium: YAG laser in otorhinolaryngolog

ISSN:0301-1569    

DOI:10.1159/000276310

出版商:S. Karger AG    

年代:1992

数据来源: Karger

ISSN:0301-1569    

DOI:10.1159/000276311

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

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.

ISSN:0301-1569    

DOI:10.1159/000276312

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The effects of oxymetazoline nose drops on the vascular permeability of the nasal mucosa in a provoked inflammatory reaction was studied in anesthetized rabbits. Vascular permeability (125I-albumin) was 53% higher in the leukotriene B4-provoked nostril (LTB4) compared with the vehicle-treated con-tralateral nostril (p < 0.05). The amount of secretions was, however, not different from the vehicle-treated side. The LTB4-induced increase in permeability was decreased by 22 % when oxymetazoline was introduced (p < 0.05), and the amount of secretions was reduced by 22% (p < 0.01). The effect of oxymetazoline on the vascular permeability of the nasal mucosa can be attributed to a vascular constriction (decrease in blood flow) and/or a change in the permeability characteristics. The LTB4-induced increase in vascular permeability was not attenuated by the monoclonal antibody IB4 directed against the neutrophil adhesion complex CD 11/CD18. The latter suggests that LTB4-induced vascular permeability does not require CD18-mediated neutrophil adherence in the nasal mucosa.

ISSN:0301-1569    

DOI:10.1159/000276313

出版商:S. Karger AG    

年代:1992

数据来源: Karger