Biomedical subjects

J Aviv

Publications and source records attributed to J Aviv.

6 recordsLinked to original sources

PubMed1997

Headaches and disease of the nose and paranasal sinuses.

Headaches resulting from disease of the nose or paranasal sinuses are usually associated with symptoms (congestion, fullness, discharge, obstruction) that point to the site of origin. Occasionally, however, nasal or sinus disease can be manifested solely as headache. In that circumstance, office nasal endoscopy in combination with a computed tomography (CT) scan of the sinuses may demonstrate an abnormality or disease of the nose or paranasal sinus. Recent studies have demonstrated that a neuropeptide (substance P) is likely to be a mediator of pain arising in the nose or paranasal sinuses.

Chronic Disease↗

PubMed1995

Instrumentation for automated determination of protein stability.

A new instrument system has been developed that automatically carries out solvent and thermal denaturations of proteins using fluorescence as a probe of structure. This instrument also automatically performs pH titrations and can make kinetic measurements on the time scale of seconds. The design philosophy and implementation are described. The prototype instrument was subjected to extensive testing. The instrument can very reproducibly and accurately collect data that allow the calculation of the thermodynamics of protein denaturation. This data collection can proceed without human intervention after acquisition start until the data are saved.

Guanidine↗

PubMed1995

Oxygen diving-induced middle ear under-aeration.

Middle ear negative pressure and effusions have been described after oxygen diving. The prevalence, dynamics and pathophysiology of this phenomenon are not clear, and were hence investigated in the present study. Thirty-four oxygen divers with normal otoscopic and tympanometric evaluation participated in the study. The subjects' symptoms were documented, and pneumatic otoscopy and tympanometry were repeated immediately after the completion of a 3 h, 15 feet oxygen dive, and 7 h later on awakening from the night's sleep. Most divers had positive otoscopic findings the morning after the dive, all of which cleared within 4 h of rising. A significant decrease was observed in average middle ear compliance (p = 0.0463, one way ANOVA), and an increase was found in the number of ears with tympanic compliance less than 0.3 ml (p = 0.0001, Kruskal-Wallis non-parametric ANOVA). In addition, 14.7% of the ears had type C, and 27.9% type B tympanograms the morning after the dive (p = 0.0001 chi2). The generalized nature of oxygen-induced middle ear under-aeration, combined with the dynamics of the symptoms and signs observed, make middle ear barotrauma, tympanic cavity oxygen absorption, and middle ear epithelial oxygen toxicity all unlikely explanations. The observed phenomenon and its dynamics might stem from a reversible derangement in a middle ear chemoreceptor reflex arch, which has recently been suggested as regulating middle ear aeration.

Acoustic Impedance Tests↗

PubMed1994

Botulinum toxin A for hyperkinetic facial lines: results of a double-blind, placebo-controlled study.

Previous work on patients with muscular dystonia has shown that small intramuscular doses of botulinum toxin A eliminated hyperkinetic facial lines for approximately 6 months. The purpose of this study was to determine the efficacy of botulinum toxin A injections in eliminating facial wrinkles in aesthetic surgery patients who do not have muscular dystonia. Eleven healthy subjects were studied in a double-blind fashion. On both sides of the face, 0.2 cc of either normal saline or botulinum toxin A was injected into the forehead or into the periorbital wrinkles (crow's feet). Documentation of results was made by photographs taken of the patients during repose and during facial animation before and after injection. Assessment of facial wrinkles was done from a grading system in which the patient and the facial plastic surgeon were asked to judge the severity of the wrinkles on a scale from 0 to 3, with 0 reflecting no facial wrinkles and 3 reflecting severe facial wrinkling. Nine of 11 subjects injected with botulinum toxin A noted a significant improvement in the severity of their facial wrinkles in comparison with the side of the face injected with saline, with a rating improvement of 2 points. Two of 11 subjects noted a moderate improvement, with a rating improvement of 1 point. No patient injected with saline reported an improvement in the severity of the facial wrinkles on the control side. There were no serious complications. Botulinum toxin A is an efficacious method of nonsurgically eliminating facial wrinkles and may play a role in the cosmetic enhancement of the aging face.

Adult↗

PubMed1986

Transcutaneous electrical stimulation of the recurrent laryngeal nerve: a method of controlling vocal cord position.

This study was designed to examine the feasibility of transcutaneous stimulation of the recurrent laryngeal nerve. Electrical activation of the recurrent laryngeal nerve was achieved by applying a blunt electrode to the intact neck skin at specific points along the tracheoesophageal groove in anesthetized adult dogs. The stimulus consisted of 10 mA cathodal pulses, each of 1 msec duration, delivered at a frequency of 10 Hz and increased by 10 Hz increments up to 100 Hz. Vocal cord excursion was directly related to the frequency of applied current. In all six dogs studies, stimulation at 30 Hz resulted in maximal ipsilateral vocal cord abduction, while stimulation at frequencies greater than 40 Hz resulted in ipsilateral vocal cord adduction up to or across the midline. Vocal cord movement was immediate and persisted for the duration of the stimulus train. Surrounding neck muscles were not visibly activated. We propose that the observed frequency-dependent movement of the vocal cords occurred because of the difference between the contraction times of the intrinsic abductor and adductor muscles of the larynx. Transcutaneous recurrent laryngeal nerve stimulation appears promising, both as a diagnostic aid in laryngoscopy and as a therapeutic tool in controlling the glottic aperture.

Animals↗

PubMedDate not supplied

Transcutaneous electrical stimulation of the recurrent laryngeal nerve in monkeys.

The recurrent laryngeal nerve (RLN) of four anesthetized adult Macaca fascicularis monkeys was stimulated by applying current with blunt electrodes placed unilaterally and bilaterally on the intact neck skin along the tracheoesophageal groove. The stimulus consisted of 2.5- to 4.0-mA cathodal pulses, each of 1-ms duration, beginning at a frequency of 10 Hz and increasing by 10-Hz increments to 100 Hz. Unilateral stimulation from 10 to 30 Hz resulted in a graded vocal cord abduction, with the maximal glottic aperture occurring at 30 Hz. Stimulation above 30 Hz produced a graded cord adduction, with nearly complete glottic closure at 100 Hz; bilateral stimulation yielded similar results, with total glottic closure at 100 Hz. Confirmation of the RLN as mediator of this frequency-dependent cord motion was achieved by surgically isolating it and attaining identical results with direct stimulation. No cardiopulmonary alterations were observed in any trial. Transcutaneous electrical stimulation of the RLN seems to be a relatively safe, reliable, and noninvasive method of controlling vocal cord position and thereby the glottic airway in monkeys.

Animals↗