摘要:

In a geometric model of passive elastic elements in the hair bundles of vertebrate acousticolateralis hair cells, Geisler provides evidence against a role of horizontal links in sensory transduction. One premise of this model, the tenet that horizontal links are stretched in the same way as tip links, may be invalid. We propose that the horizontal links may be rigid, implying that the attachment points of the horizontal links in the stereociliary membrane must move when the hair bundle is deflected. Since the movement is linear with the angle of deflection, a connection of transduction channels and horizontal links is conceivable.

ISSN:0301-1569    

DOI:10.1159/000276785

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Endothelin (ET) has been revealed to be a local hormonal regulator of pressure, fluid, ions and neurotransmitters. In order to investigate the mechanism of homeostasis within the microenvironment of the inner ear, the present study has examined the distribution of ET in the vestibule of normal guinea pigs, by immunohistochemistry using mouse antihuman ET IgGl monoclonal antibody. ET-like activity was identified in the sensory epithelial cells, supporting cells, dark cells, transitional cells, vestibular membrane, semicircular wall cells and vestibular ganglion cells. These findings suggest that ET may play an important role in maintaining homeostasis of the vestibule.

ISSN:0301-1569    

DOI:10.1159/000276786

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Untreated specimens (i.e. not fixed, dehydrated or embedded) of the otolithic membrane from the sacculus of guinea pigs were observed at the ultrastructural level by low-vacuum scanning electron microscopy (LVSEM). This technique revealed the presence of a 15- to 20-µm-thick layer of an amorphous substance (the supraotolithic cupula zone) on the surface of the otoliths, which was not detectable by conventional methods. Elemental analysis of this substance revealed relatively high concentrations of oxygen, sodium, phosphorus, chlorine, potassium and calcium. This amorphous substance was thought to have a role in fixing the otoliths onto the sensory epithelium. In addition, the tips of the triangular portions of the otoliths were not sharp as shown by conventional SEM and were seen to be more rounded by LVSEM

ISSN:0301-1569    

DOI:10.1159/000276787

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

This report defines the conditions for changes in the phosphorylation state of neurofilaments (NF) after facial nerve lesions. In adult control rats, few phosphorylated neurofilament (pNF) epitopes were stained (using SMI 31 antibodies) in a small subpopulation of facial motoneurons. After various types of mechanical lesion (nerve transection with and without attaching a metal clip to the proximal nerve trunk, nerve crush, combined trigeminal and facial nerve lesions) of the right facial nerve, pNF immunoreactivity transiently increased in most cell bodies of facial motoneurons on the operated side. This pNF ‘reaction’ started within 2 days after the operation and persisted up to 2 weeks but remained longer in those animals in which axonal regeneration had been prevented or delayed by attaching a metal clip to the proximal nerve stump. After botulinum toxin application into facial muscles (i.e. inhibition of synaptic transmission at motoric endplates) there was no increase in the amount of pNF after 4 and 10 days, but it appeared in facial nuclei 4 weeks after injection on both, the treated and the untreated side, i.e. during functional restitution. Selectively transecting the ‘vibrissal part’ of the trigeminal nerve induced no obvious changes in the pNF immunoreactivity in facial motoneurons, but a combined trigeminal-facial lesion did. Labeling nonphosphorylated epitopes (using SMI 32 antibodies) showed a slight decrease in immunoreactivity in the neuropil of the facial nucleus 15 days after nerve transection and fixing a metal clip on the proximal nerv

ISSN:0301-1569    

DOI:10.1159/000276788

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Cholesteatoma epithelium is characterized by a keratinocyte dysregulation with aggressive growth subsequently destroying the middle ear mucosa. The monoclonal antibody Ki-67 recognizes a nuclear antigen expressed by cells in the G1, S, and G2/M phases being used to determine the growing cell fraction in tissue samples. Cryostat sections of skin and cholesteatoma biopsies were examined immunohistochemically for reactivity with Ki-67 using the alkaline phosphatase-anti-alkaline phosphatase method. Nuclear staining was seen in a small number of keratinocytes located in the basal cell layer of normal auditory meatal skin. In contrast, numerous cells of the basal and suprabasal layers in cholesteatoma were found to react with Ki-67. A cytoplasmic staining was also observed in both skin and cholesteatoma. In cholesteatoma, the cytoplasmic staining was stronger. These results clearly show that cholesteatoma epithelium proliferates at a higher rate than normal epidermis, confirming the hyperproliferative behavior of cholesteatoma.

ISSN:0301-1569    

DOI:10.1159/000276789

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Investigators have attempted to simplify and improve myringoplasty. However, techniques have not been applied to large, chronic human tympanic membrane perforations. Fibrin glue has been shown to improve wound strength but has not been significantly utilized in myringoplasty. To evaluate the effectiveness of paper patch myringoplasty reinforced with fibrin glue, 15 guinea pigs underwent repeated myringectomy to form persistent ( > 50%) perforations. The right ears were repaired with a paper patch and fibrin glue (treatment group), and the left ears with a paper patch alone (control group). Of 16 surviving ears (9 right and 7 left), only 1 a left ear, failed to heal. In the control group, histology revealed a larger fibrous layer approaching greater total eardrum thickness than in the treatment group. Neither group was significantly different from a normal, nonoperated tympanic membrane in terms of overall thickness. Fibrin glue failed to demonstrate histologic evidence of increased cellular proliferation and possibly hindered growth. High spontaneous healing rates in guinea pigs undermine myringoplasty modeling.

ISSN:0301-1569    

DOI:10.1159/000276790

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Facial movement following hypoglossal-facial nerve anastomosis was investigated in 29 acoustic neuroma patients. The amount of facial movement was assessed using both the grading system of House and Brackmann and the revised grading scale of Yanagihara. The data were analyzed to determine the influence of the time elapsed between tumor resection and anastomosis upon recovery of facial movement. A slightly larger number of patients with delayed anastomosis (7–23 months) showed minimally poorer results than those with early anastomosis (within 3 months). However, these differences were not statistically significant. Moreover, there was no apparent relationship between the duration of facial nerve paralysis and the recovery of facial movement within either of these two groups. These results showed that hypoglossal-facial nerve anastomosis can be delayed up to 2 years following tumor resection with only minimal effect on the recovery of facial movemen

ISSN:0301-1569    

DOI:10.1159/000276791

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

A report on the surgical findings and long-term results of 68 revision tympano-plasties performed at King Abdul Aziz University Hospital over a period of 7 years is presented. Temporalis fascia was used in all operations, with an overall success rate of 85% of graft take up, with significant improvement of hearing in the majority of cases. The causes of immediate failure were found to be due to faulty surgical techniques, however most of the late reperforations were due to infections and in some to atrophy of the graft. It is concluded that better surgical technique and improvement of medical facilities in most rural areas are of utmost importance in Saudi Arabia.

ISSN:0301-1569    

DOI:10.1159/000276792

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

This is a retrospective study of a limited group of 30 patients, children and adults, diagnosed as having cholesteatomas. Analysis includes audiological data and surgical results. Two techniques were used in surgery. In half of the cases, an obliteration technique was used, and in the remainder an open radical cavity was created. The method used was determined by the surgeon and in some measure by the extent of the disease. Our conclusions are that the obliteration technique offers better hearing results than the open-cavity technique. The number of residuals over a 4- to 5-year period was acceptable and cavity problems were avoided.

ISSN:0301-1569    

DOI:10.1159/000276793

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

We investigated the incidence of spontaneous nystagmus in 30 normal volunteers using electronystagmography (ENG). In all subjects, ENG was performed with the eyes open in the primary position, with the eyes closed, and with the eyes open in total darkness. Spontaneous nystagmus was detected in 5 (16.7%) of 30 subjects. In 15 subjects who underwent 2 ENG examinations, 4 subjects (26.7%) exhibited spontaneous nystagmus. Caloric testing was performed in 26 of 30 subjects. Spontaneous nystagmus was detected in 3 subjects who had a right-left difference in caloric response of over 40%, and in 2 of 23 subjects who had a difference of less than 40%. Our results showed that spontaneous nystagmus was detected in more subjects when the ENG examinations were repeated. Thus, a single ENG examination cannot exclude the possibility of spontaneous nystagmus.

ISSN:0301-1569    

DOI:10.1159/000276794

出版商:S. Karger AG    

年代:1996

数据来源: Karger