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Biomedical subjects

J Elidan

Publications and source records attributed to J Elidan.

At least 73 records · Page 4Linked to original sources
PubMed1987

Recording of short-latency vestibular evoked potentials induced by acceleration impulses in experimental animals: current status of the method and its applications.

The short-latency vestibular evoked potential (VsEP) induced by angular acceleration impulses (maximal amplitude 30,000 deg/sec2, rise time 2-3 msec) was recorded by skin electrodes in intact cats after various surgical and pharmacological procedures. The normal VsEP consists of 5-8 waves, several microvolts in amplitude, during the first 10 msec. The latency of the first wave (P1) is about 2 msec with respect to the start of head acceleration. The first and the second waves (P1 and P2) were shown to originate from the vestibular nerve and nucleus, respectively. The VsEP disappears permanently after bilateral labyrinthectomy, excision of the 8th nerves, or administration of large doses of gentamicin. Temporary disappearance is caused by anoxia induced for a brief period of time or injection of lidocaine (4%) into the vestibular nerve or into the inner ear after contralateral labyrinthectomy. The VsEPs in the intact cat are similar whether clockwise or counterclockwise stimuli are used and are not affected by changing the position of the head. Unilaterally labyrinthectomized animals, however, show asymmetric response whereby excitatory stimulation of any of the intact semicircular canals evokes prominent P1 and P2 waves which are absent with inhibitory stimulation. The rate and input-output intensity functions of the VsEP are described. The threshold of the VsEP was found to be 1000-1500 deg/sec2. In addition to the neurogenic waves, 2 other potentials appear occasionally in the response: large-amplitude and longer-duration waves with latencies of 8-20 msec, which are of myogenic origin, and smaller waves with shorter latency which probably represent vestibular microphonics and generator potentials. Extracellular recordings of the responses of single second-order neurons in the vestibular nuclei to the same acceleration impulses confirmed that the kinetic vestibular neurons can respond to these stimuli with a latency as short as 3.5 msec. This method for inducing and recording VsEPs has proved to be a powerful tool for the evaluation of vestibular function in experimental animal models.

Acceleration↗
PubMed1987

Vestibular ototoxicity of gentamicin assessed by the recording of a short-latency vestibular-evoked response in cats.

The short-latency vestibular-evoked response (VsER) and the auditory brain stem response (ABR) were recorded with scalp electrodes in four cats before, during, and after systemic administration of gentamicin. The VsER was altered and later disappeared in three cats, and in one cat it became asymmetric, typical of a unilateral vestibular lesion. In all cats the ABR was unaffected and remained normal through the end of the experiment 4 months later. Histopathological examination of the temporal bones of three cats showed severe damage to the vestibular end-organ, particularly in the summit of the cristae, but in lesser amounts in the hair cells on the slopes of the cristae and in the maculae. In one cat, the pathological condition was greater in one ear, corresponding to the asymmetry in the VsER records. This new method of inducing and recording the VsER has been demonstrated by the present study to be an effective tool for experimentally assessing vestibular end-organ and nerve function in animal models. Furthermore, these results indicate that the VsER is generated in the vestibular labyrinth, most probably by the cristae of the semicircular canals.

Animals↗
PubMed1986

The effect of loop diuretics on the vestibular system. Assessment by recording the vestibular evoked response.

Whether or to what extent loop diuretics, e.g., ethacrynic acid and furosemide, affect the vestibular system is controversial. We studied this problem by recording in cats the short-latency vestibular evoked response (VsER) to acceleration stimuli by skin electrodes before and after local or systemic administration of loop diuretics. The effect on the VsER was minimal in contrast to the major changes that appeared in the auditory evoked response, in which, among the waves known to originate from the brain stem, the most affected was N1. These findings suggest that the vestibular end-organ function is minimally affected by loop diuretics and that the changes in the vestibulo-ocular reflex reported by several authors might be due to the effect of the drugs on the central nervous system. Thus, recording of the VsER in experimental animal models might serve as a useful tool for direct evaluation of the effect of certain drugs and conditions on the vestibular system.

Animals↗
PubMed1985

Ear involvement in human brucellosis.

A case report of mixed-type hearing loss following brucella infection is presented. Damage to the ear in brucellosis is well documented in the Polish literature whereas, surprisingly, it is not mentioned in the otolaryngologic and microbiologic English literature. Otolaryngologists should be aware of possible ear damage in brucellosis, in order to be helpful in the diagnostic process, with the aim of starting antibiotic treatment as soon as possible, in order to prevent irreversible ear damage.

Acute Disease↗
PubMed1985

On the vertical caloric nystagmus.

Eye movements in response to caloric stimuli are recorded traditionally in the horizontal plane only. Twin channel electronystagmographic traces of 124 patients undergoing evaluation of vertigo were reviewed. Thirty traces (24%) were found to include a "true" vertical component to the evoked nystagmus. There was no correlation between the existence and the nature of any vestibular pathology and the presence of the vertical nystagmus. Thus, a vertical component to the caloric nystagmus (the so-called "perverted" caloric nystagmus) is not necessarily a pathological sign, and can be a normal variant, caused by excitation of the vertical semicircular canal - most probably the posterior one. The mechanisms of heat transfer in the temporal bone and the source of this vertical caloric nystagmus are discussed in the context of the published literature.

Caloric Tests↗
PubMed1984

Square wave jerks--incidence, characteristic, and significance.

Square wave jerks (SWJ) are saccadic eye movements which, when recorded with open eyes are considered to be a pathological sign, caused by fixation instability, and pointing to a central neurological lesion. In reviewing 429 electronystagmographic traces, 85 (20%) were found to include the pattern of SWJ. Among them, in 38 traces, SWJ have been recorded with open eyes during fixation. Many of these cases were found to suffer from definite peripheral vestibular pathology, and some of them did not reveal any sign of neurological pathology in the clinical evaluation and by electronystagmography. Thus, SWJ are non-specific rapid eye movements, which do not necessarily point to neurological pathology. The literature is reviewed and the possible neural mechanism for the production of SWJ is discussed.

Adult↗
PubMed1982

Recording of short latency vestibular evoked potentials to acceleration in rats by means of skin electrodes.

Short latency (less than 15 msec) vestibular potentials evoked by short and intense acceleration stimuli were recorded in rats by surface electrodes, using electronic filtering and with averaging techniques. The evoked potential is strongly dependent on the direction of rotation and on the angle of the head, and it disappears after labyrinthectomy or sectioning the 8th nerve. All these facts point to its vestibular origin. Although these results were obtained in rats, the importance and the significance of recording a vestibular evoked potential in man is obvious. It would lead to the possibility of objective verification of a vestibular disorder and localization of the lesion.

Animals↗
PubMed1982

Contribution of changes in click rate and intensity on diagnosis of multiple sclerosis by brainstem auditory evoked potentials.

Brainstem auditory evoked potentials (BAEPs) were recorded in 51 patients with different degrees of certainty with respect to multiple sclerosis (MS): Definite, probable and possible (McAlpine et al. 1972). Click stimuli were presented at various intensities and rates which were thought to stress the auditory pathways. The main types of abnormal BAEP traces were the absence of some of the brainstem waves (in the presence of a normal audiogram), prolonged brainstem transmission time (BTT) and abnormal amplitude ratio. In the definite MS group, average BTT was prolonged and average amplitude ratio was more than two standard deviations greater than the corresponding parameter in the normal group. The stressful manoeuvres of increasing click repetition rate and lowering click intensity increased the degree of abnormality of BAEP traces. There was no case in which the response to standard click stimuli (75 dB HL, 10 or 20 per sec) showed a normal trace while increasing the stimulus repetition rate and/or decreasing intensity showed a pathological response. The pathophysiology of BAEP traces in MS is discussed.

Adolescent↗
PubMed1980

Pneumoperitoneum induced by pneumatosis cystoides intestinalis associated with volvulus of the stomach.

A rare association of pneumoperitoneum induced by pneumatosis cystoides intestinalis with chronic mesenteroaxial volvulus of an irreducible stomach in a paraesophageal hiatus hernia is described. The importance of accurate radiologic work-up is emphasized. The possible significance of this association to explain the pathogenesis of pneumatosis cystoides intestinalis is discussed.

Aged↗
PubMed1975

Leukocyte alkaline phosphatase in newborn infants after delivery and in the puerperium.

Leukocyte alkaline phosphatase (LAP) activity increases progressively during pregnancy, returning to non-pregnant levels 6 weeks post-partum. This enzymatic activity is under the influence of placental steroid hormones, thus reflecting placental function. LAP activity is thus a reflection of the dynamic relations between estrogenic, progestational and corticoid activity during pregnancy. LAP activity was studied in 60 women and in their 61 newborn infants at delivery and during the first five days of the puerperium. The Kaplow cytochemical technique was employed. The average maternal LAP score as well as the average newborn infant LAP score was considerably higher than the LAP score of the normal adult. The level of the enzyme in the maternal granulocytes was significantly higher than that of the newborn (Tab. I). During the first five days after labor, there was progressive decrease in the LAP score in the maternal and the newborn blood; on the fifth day the LAP scores of both were only slightly above the normal adult score (Figs. 1, 2). An inverse relation between the LAP score and the birth weight of the infant was found (Tab. III). These results confirm the view that LAP activity in the fetus in utero, are dependent on placental steroid function. The lower LAP values in the newborn, as compared to those of the mother are probably dependent on the lower newborn hormone levels. The significance of the relation between LAP scores and the infants birth weight is not clear.

Alkaline Phosphatase↗
PubMedDate not supplied

Skull base chondroma of extracranial origin.

METHODS: Two cases of chondroma at the skull base, most probably of extracranial origin, are presented: one at the apex of the petrous pyramid and the other in the infratemporal fossa. RESULTS: In the second case, the surgical findings suggested that the tumor originated in the cartilagineous part of the eustachian tube. The world literature was reviewed and only three cases of extracranial chondromas at the skull base, and ten cases of chondromas of the nasopharynx have been described so far. CONCLUSIONS: The potential origins of chondromas at the skull base are discussed: Cartilagineous remnants at the basisphenoid and basiocciput or the cartilagineous part of the eustachian tube seem to be the most probable origin.

Chondroma↗