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Biomedical subjects

R W Babin

Publications and source records attributed to R W Babin.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Second-order neural responses after contralateral vestibular nerve sectioning.

The characteristics of the response to an 8 degrees/sec2 acceleration of 41 neurons in the medial vestibular nucleus of the cat following vestibular nerve sectioning were compared with those of 73 control neurons at the same site. In 14 of the vestibular nerve-sectioned animals the same neuron was recorded before and after sectioning. No difference was found between the resting discharge rates, maximal response rates, and rates of adaptation of the two groups. Following contralateral vestibular nerve sectioning Type II neurons were still plentiful, suggesting many receive ipsilateral labyrinthine innervation.

Action Potentials↗
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Effects of ketamine on the adaptive responses of second-order vestibular neurons of the cat.

The adaptive characteristics of 80 neurons in the vestibular nuclei of ketamine-anesthetized cats were investigated. All types I and II neurons responded to stimulation of the horizontal semicircular canals by an 8 degree/sec2 stepwise angular acceleration of 40 sec. For the purpose of this study, vestibular adaptation was defined as a decline in response at a rate of greater than -0.01 spikes/sec/sec. According to this criterion, 71 neurons (89 per cent) behaved as adapting neurons, and nine (11 per cent) showed either no adaptation or reverse adaptation. The rate of adaptation varied from neuron to neuron; the average rate was -0.312 spikes/sec/sec. The average resting discharge rate, the maximum response level, and the average adaptation rate were compared with similar neural responses in barbiturate-anesthetized cats. Although the average resting discharge rates of the two groups showed no significant difference, the average adaptation rate and the maximum response level of the ketamine-anesthetized group were significantly higher than those of the barbiturate-anesthetized group. These data suggest that the gain of the second-order neurons is higher and more actively modulated in more alert (ketamine-anesthetized) cats than in barbiturate-anesthetized cats.

Animals↗
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Pigmented lesion of the middle ear: report of a case.

Melanotic lesions of the mucosal membranes of the head and neck have been reported infrequently. Malignant melanomas are reported with much more frequency than benign nevi in this region. The first reported case of a nevus of the middle ear mucosa is presented. The distinctions between this lesion, nevus of Ota, meningioma, Schwannoma, and hematoma are discussed. The malignant potential for this lesion is not known, but it appears low enough to obviate interval tympanotomy.

Adult↗
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Asymmetry of the internal auditory canals without acoustic neuroma.

During the past five years, nine patients with "significant" unilateral enlargement of one internal auditory canal by polytomography were subsequently found to have freely filling canals on contrast posterior fossa myelography. The radiographic appearance of the enlarged canals varied greatly and included all the various configurations usually suggestive of acoustic neuroma. Likewise, the clinical presentation varied greatly from asymptomatic to highly suggesting of cerebellopontine angle tumor. This series underscores the essential nature of posterior fossa studies in the evaluation of potential acoustic neuromas and the variability of the normal architecture of the internal auditory meatus.

Adolescent↗
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Second-order vestibular adaptation and cupular dynamics.

The magnitude of initial response and slope of continued response of 45 neurons in the vestibular nuclei of cats to constant and interrupted accelerations were investigated. Eighty-eight percent exhibited adaptation, the magnitude of which was proportional to the stimulus. Comparison of slope and intercept of the response to continuous acceleration before and after a superimposed inhibitory velocity change suggests that the adaptation phenomenon is unrelated to cupular position.

Acceleration↗
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Management of benign fistulae between Zenker's diverticulum and the trachea.

Cases of acquired benign fistula of the respiratory tree and esophagus have been reported in relation to Mycobacterium tuberculosis and trauma. Fistula formation between the trachea and a Zenker's diverticulum is a similar type of condition in which nutritional and immunological deficiencies can rapidly result in further complications which may mimic a malignancy. Spontaneous fistula formation and vocal cord paralysis may result. Surgical management of this condition includes interposing viable muscle between the esophagus and trachea at the repair site.

Aged↗
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Transdermal scopolamine in the treatment of acute vertigo.

A double-blind, parallel investigation was undertaken to evaluate the efficacy of transdermally delivered scopolamine hydrobromide in acute vertigo as compared to meclizine hydrochloride and placebo. Statistical analysis of subjective patient responses and clinical observations suggested that both scopolamine and meclizine are more effective than placebo. Both have significant, but different, side effects.

Acute Disease↗
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Histopathology of neurosensory deafness in sarcoidosis.

Sarcoidosis is an idiopathic systemic granulomatous disease which occasionally causes fluctuating auditory and vestibular dysfunction. The temporal bones from a 32-year-old man deaf for 5 years from CNS sarcoidosis were examined histologically and compared with other nervous system tissues. It was found that the acoustic, vestibular, and facial nerves were involved in a striking perivascular lymphocytic infiltration resulting in myelin and axonal degeneration. The cochlear and labyrinthine neuroepithelium and stria vascularis had degenerated. It is hypothesized that neurosensory deafness and vestibular dysfunction in sarcoidosis starts as a reversible neuropathy. In some patients, an ischemia secondary to the vasculitis results in irreversible damage to the inner ear neuroepithelium.

Adult↗
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Endoscopic surgical management for laryngomalacia. Case report and review of the literature.

Laryngomalacia is the most common of the many causes of respiratory stridor in the newborn. It may be identified by fiberoptic nasopharyngoscopy in the nursery or office. Several anatomic mechanisms of supraglottic collapse have been reported in the literature. The most common is a narrowing of the supraglottic airway with blockage of the glottic opening by the redundant tissue of the aryepiglottic folds. Although surgery rarely is indicated, severe airway obstruction, necessitating surgical intervention, can occur. Resection of supraglottic tissue should be performed only as an alternative to tracheotomy. Surgical procedures ranging from tracheotomy to epiglottidectomy have been advocated. Direct visualization of the obstructing tissue by nasopharyngoscopy allows the planning of an appropriate surgical procedure. In a patient with lateral supraglottic collapse, deep resection of the epiglottis would be expected to weaken the support of the aryepiglottic folds and aggravate the airway condition. Similarly, resection of tissue along the aryepiglottic folds will be useful only if preoperative evaluation demonstrates the obstruction to be at this location.

Airway Obstruction↗
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Ectopic striated muscle in the fallopian canal: a histopathologic report.

Two temporal bones are discussed that contain ectopic striated muscle in the horizontal fallopian canal. In one instance, this muscle was clearly innervated by a branch from the geniculate ganglion. This is an unusual histologic finding and the innervation to such a muscle has been rarely identified. The facial nerve surgeon should be aware that a mass encountered during decompression may be developmental rather than neoplastic.

Bone Neoplasms↗
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The freeze-injection method of hypertrophic scar and keloid reduction.

Hypertrophic scars and keloids continue to plague the head and neck surgeon as an unpredictable consequence of trauma or incision. The myriad suggested methods of revising such lesions indicate that no one method is foolproof. The application of conventional cryotherapy to the lesion, followed by the dilute intralesional triamcinalone injection, offers several advantages over other methods.

Cicatrix↗
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The effect of blood pressure on compression-induced facial nerve neuropraxia in the cat.

The facial nerves of 21 adult anesthetized cats were exposed from the parotid gland to the orbicularis oculi muscle. The summated action potential (SAP) of the orbicularis oculi muscle was recorded. A calibrated pressure block was applied to the intact facial nerve between the stimulating electrode and the muscle. Pressures of between 150 and 200 mm Hg caused a rapid stable neuropraxia. In ten animals the blood pressure was elevated by a constant levarterenol infusion. In 11 animals the blood pressure was elevated by coarcting the abdominal aorta and volume overloading the rostral vascular system. In both groups, in all animals, when the systolic blood pressure exceeded the pressure applied to the nerve, a substantial increase in SAP amplitude was noted. If the systolic pressure was allowed to fall below the pressure on the nerve, the neuropraxia rapidly returned. This data suggest that within a physiologic pressure range of 150 to 200 mm Hg there is a reversible ischemic phase of compression neuropraxia and it is in complete accord with the earlier work of Devriese.

Animals↗
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Cis-diamminedichloroplatinum (II) ototoxicity in the guinea pig.

Cochleas from 12 guinea pigs were evaluated using light, scanning, and transmission electron microscopy after systemic administration of cis-diamminedichloroplatinum (cis-DDP). Administration of cis-DDP resulted in loss of the Preyer reflex and degeneration of outer hair cells (OHC) with increased dose. The OHC degeneration was most pronounced in the basal turns of the cochlea with greatest severity in the inner row. Ultrastructural evidence of OHC degeneration included dilatation of the parietal membranes, softening of the cuticular plate, increased vacuolization and increased numbers of lysosome-like bodies in the apical portion of the cell. Supporting cells appeared more sensitive than OHC. Alteration of supporting cell ultrastructure preceded detectable change in OHC. Injury to the supporting cells was noted with intracellular vesiculation and increased autophagocytosis.

Animals↗