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Biomedical subjects

J Elidan

Publications and source records attributed to J Elidan.

84 records · Page 5Linked to original sources
PubMedDate not supplied

Short and middle latency vestibular evoked responses to acceleration in man.

We have succeeded in recording short and middle latency vestibular evoked responses in human subjects. The head was held rigidly in a special, patented head holder, constructed individually for each subject, which gripped the teeth of the upper jaw. The stimulus consisted of 2/sec steps of angular acceleration impulses produced by a special motor with intensities of about 10,000 degrees/sec 2 and with a rise time of 1-2 msec. The electrical activity was recorded as the potential difference between special forehead and mastoid electrodes having a large, secure contact area with the skin. The activity was digitally filtered and averaged in 2 separate channels by means of a Microshev 2000 evoked response system. The short latency responses, with peaks at about 3.5 msec (forehead positive), 6.0 msec (forehead negative) and 8.4 msec (forehead positive; bandpass: 200-2000 Hz; average of 1024 trials), had amplitudes of about 0.5 microV. The middle latency responses had peaks at about 8.8 msec (forehead positive), 18.8 msec (forehead negative) and 26.8 msec (forehead positive; 30-300 Hz; N = 128 trials), with larger amplitudes (about 15 microV). These responses were consistently recorded in the same subject at different times and were similar in different normal subjects. Strenuous control experiments were conducted in order to ensure that these responses are not artefacts due to the movement of conducting media (head, electrodes and leads) in the electromagnetic field of the motor and are elicited by activation of normal labyrinths.(ABSTRACT TRUNCATED AT 250 WORDS)

Acceleration↗
PubMedDate not supplied

The contribution of the lateral semicircular canal to the short latency vestibular evoked potentials in cat.

Short latency vestibular evoked potentials (VsEPs) to angular acceleration impulses (maximal intensity 20,000 degrees/sec2, rise time 1.5-3 msec) were recorded by skin electrodes in cats before and after various surgical procedures. Under general anesthesia, the animals underwent unilateral labyrinthectomy and the VsEPs in response to stimulation of the remaining inner ear in the plane of the lateral semicicular canal (SCC) with the head flexed 20 degrees-25 degrees were recorded as a baseline. The lateral SCC was then selectively obliterated near its ampulla. This induced major changes in the VsEPs recorded in response to stimulation of the remaining inner ear in this plane: the first 2 VsEP waves were absent, and only longer latency, smaller amplitude waves were present in response to both clockwise and counterclockwise stimulation. On the other hand, obliteration of the anterior and posterior SCCs and, in addition, destruction of both maculae were without major effects on the first 2 VsEP waves in response to excitatory stimulation. The results confirm that when the head is flexed 20 degrees-25 degrees and stimulated with angular acceleration impulses in the horizontal plane, the major site of initiation of the VsEPs in cats and probably in man is the crista ampullaris of the lateral SCC.

Acoustic Stimulation↗
PubMedDate not supplied

Nasopharyngeal carcinoma among the population in Jerusalem.

PURPOSE: Because the incidence of nasopharyngeal carcinoma differs in various ethnic groups, the heterogeneous population of Jerusalem was selected for an epidemiologic study. MATERIALS AND METHODS: Data from 63 consecutive patients diagnosed with nasopharyngeal carcinoma were collected in a retrospective manner. Information regarding sex, age, ethnic origin, tobacco and alcohol consumption, chronic sinusitis, and immunoglobulin (Ig)G to Epstein-Barr virus capsid antigen was tabulated and was statistically analyzed by the z test. RESULTS: The results showed an increased incidence of disease in the Sephardi Jews, especially of Moroccan origin. The histologic type was 100% poorly differentiated squamous carcinoma, and was associated with a better prognosis than is usually seen in the literature. CONCLUSION: This study identified an ethnic-related pattern of nasopharyngeal carcinoma in Jerusalem, and found a 100% incidence of poorly differentiated squamous carcinoma, and a better survival rate than the literature suggests, which may be attributable to the histologic type.

Adolescent↗
PubMedDate not supplied

Direction-changing positional nystagmus: incidence and meaning.

Direction-changing positional nystagmus (DCPN) is a nystagmus that changes its direction with different body and head positions. Many authors consider that it indicates the presence of a central nervous system lesion. Of 1,196 patients whose abnormal electronystagmographic (ENG) traces were reviewed, 46 (3.8 per cent) showed DCPN. Of these, ten (22 per cent) had central neurologic diseases, 14 (30 per cent) had peripheral vestibular diseases, and for 22 (48 per cent) there was no definite clinical diagnosis. Nineteen patients (41 per cent) with DCPN had ENG findings suggesting a peripheral vestibular lesion, while only five (11 per cent) had ENG findings suggesting a central vestibular lesion. Four of 44 control subjects exhibited DCPN. Thus, the presence of DCPN does not necessarily indicate disease of the vestibular system and definitely does not localize the site of a lesion in the vestibular pathways, but more often indicates a peripheral vestibular site. As with spontaneous nystagmus, lack of suppression with fixation suggests a central lesion.

Adult↗
PubMedDate not supplied

Chondrosarcoma at the skull base.

A rare case of chondrosarcoma at the skull base is presented. Computerized tomography scan was very helpful in delineating the exact extent of the tumor. Chondrosarcoma is a slow growing malignant tumor which metastasizes very late. Usually it is radioresistant, but when surgery is not feasible, irradiation treatment is worth a trial.

Chondrosarcoma↗
PubMedDate not supplied

Irrigation of the maxillary sinus by canine fossa puncture. Experience with 202 patients.

Maxillary sinus lavage through the canine fossa was performed on 202 patients. This procedure is relatively safe, easily learned and quickly performed, has minimal side effects and a very low percentage of failures, and is more acceptable to most patients. It should be used by otolaryngologists, at least as a useful alternative to the classical method.

Adult↗
PubMedDate not supplied

Short latency vestibular evoked response to acceleration stimuli recorded by skin electrodes.

Short latency vestibular evoked response to repetitive acceleration stimuli were recorded by skin electrodes in cats, using electronic filtering and averaging techniques. The evoked response is composed of six to eight waves during the first 10 ms after the stimulus. These are followed by longer latency responses which are myogenic in nature. All of these waves disappear with the animal's death and after excision of both eighth nerves. In recordings from the animal after excision of the eighth nerve on one side, the response patterns of excitation versus inhibition are demonstrated using excitatory and inhibitory acceleration stimuli. The possible generators of the evoked response are discussed in the light of the physiology of the vestibular pathways.

Animals↗
PubMedDate not supplied

Dysphonia caused by Forestier's disease.

A case of diffuse idiopathic skeletal hyperostosis (Forestier's disease) causing dysphonia as the presenting and only symptom is reported. The dysphonia is attributed to the mass effect in the hypopharynx and the mild pressure on the larynx. The bony mass anterior to the vertebral body is demonstrated by CT scan for the first time in the literature on Forestier's disease.

Humans↗
PubMedDate not supplied

Transient evoked otoacoustic emissions in newborns in the first 48 hours after birth.

Newborns are often discharged from hospital at the age of about 48 hours. At this age, transient evoked otoacoustic emissions (TEOAEs) are not necessarily recordable in all healthy newborns. In order to determine the factors which would enable the successful recording of TEOAEs before discharge to facilitate screening for hearing, 65 fullterm newborns under 48 hours of age were tested, the youngest being 10 hours old. The ears of those neonates in whom TEOAEs could not be obtained (N = 7 neonates bilaterally, 6 unilaterally) were examined otoscopically, cleaned of vernix and retested for TEOAEs. We were thus able to record in at least one ear in all neonates tested, if the ears were clean, if they were asleep and if the testing room was quiet.

Acoustic Stimulation↗
PubMedDate not supplied

Indications for gadolinium-DTPA in magnetic resonance evaluation of extracranial head and neck mass lesions: review of experience with 27 patients examined with a 2 tesla imager.

The authors review their experience with 27 patients who underwent gadolinium-enhanced magnetic resonance imaging (MRI) at 2 tesla. The contribution of the contrast agent was evaluated with respect to three properties--lesion conspicuity, margins and characterization. Gadolinium enhancement contributed most to the characterization of the lesion and helped to better define lesion margins in relationship to nonfatty tissues. It is concluded that gadolinium-enhanced MR images frequently give significant additional information in the evaluation of head and neck mass lesions.

Contrast Media↗