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At least 19 recordsLinked to original sources
PubMed1990

[Reflex control on laryngeal functions--vibration effect of the laryngeal mucosa on recurrent laryngeal nerve reflexes].

Electromyographic (EMG) responses of the intrinsic laryngeal muscle have been investigated to clarify reflexogenic laryngeal controls from a viewpoint of its functional significance during phonation. Twenty-five adult cats were anesthetized with intraperitoneal injection of 4ml/kg of a mixture of 10% urethane and 1% alpha-chloralose. Either the internal branch of the superior laryngeal nerve (ISLN) or the recurrent laryngeal nerve (RLN) was carefully dissected and central end of the dissected nerve was electrically stimulated. EMG of the contra-lateral Thyro-Arytenoid muscle (TA muscle) to the stimulation was recorded using a hooked-wire electrode inserted through the laryngeal mucosa. EMG of the TA muscle evoked by the stimulation of the ISLN were analyzed with respect to its latency and discharge pattern inter-collicular brainstem transsected. Together with the stimulation of the RLN, vibratory stimuli were given mainly to the subglottic mucosa as conditioning stimuli. The vibratory frequency was changed from 50Hz to 400Hz step-wisely. Following results were obtained. 1. EMG response of the contra-lateral TA muscle to the stimulation of the ISLN showed two different kinds of latency, approximately 8-10msec, and 40-60msec. 2. After inter-collicular brainstem transsection, evoked response of the latter disappeared. This result indicates that the ISLN-RLN reflex loop consisted of more than two routes, different in the number of synaptic junctions. 3. The vibratory stimuli given to the laryngeal mucosa had facilitatory effect on the reflexive EMG response evoked by the stimulation of the RLN. 4. This facilitatory effect of the vibratory stimuli disappeared after topical anesthesia of the laryngeal mucosa. 5. The facilitatory effect on the reflex responses was partially increased depending on the vibratory frequencies applied. In conclusion, vibratory stimuli to the laryngeal mucosa reflexively modulate the activity of the intrinsic laryngeal muscles.

Animals↗
PubMed1992

[Reflex control of laryngeal functions in the cat: the effect of vibratory stimuli of the laryngeal mucosa on the laryngeal reflex].

To investigate the effect of vibratory stimuli of the subglottic mucosa on the laryngeal reflex, experiments were performed on cats anesthetized with intraperitoneal injection of a mixture of urethane and chloralose. The external branch of the superior laryngeal nerve was cut, while the internal branch of the superior laryngeal nerve (ISLN) was mounted on stimulating electrodes. Electromyograms (EMG) were recorded from the contralateral thyreoarytenoid (TA), posterior cricoarytenoid (PCA), lateral cricoarytenoid (LCA), and cricothyreoid (CT) muscles. When the ISLN was electrically stimulated, the laryngeal reflex was induced. Short latency (early) and long latency (late) responses were observed in TA, PCA, LCA, and CT. Then, vibratory stimuli were applied to the surface of the subglottic mucosa. Vibratory frequencies used in this study were varied stepwise from 100 Hz to 400 Hz, with the amplitude adjusted at 20 microns. Vibratory stimuli had no effect on early responses but did, however, exert a facilitatory effect on late responses of TA and LCA in the transitional phase from inspiration to expiration and on late responses of PCA in the inspiratory phase. After denervation of ISLN, the vibratory effect on late responses disappeared completely. No significant vibratory effect was observed on CT in any respiratory phase. These results suggest that vibratory stimuli applied to the surface of the subglottic mucosa reflexively facilitate the laryngeal reflex and that ISLN afferents and respiratory drive modulate the laryngeal reflex.

Animals↗
PubMed1989

[DNA content in laryngeal keratosis, laryngeal cancer and normal laryngeal epithelium].

The DNA content in laryngeal precancerous lesion, laryngeal keratosis, laryngeal carcinoma and normal laryngeal epithelium had been measured in order to study the relationship between histopathologic picture and DNA content. The results showed that the DNA content in keratotic tissue increased to varying degrees as compared with the normal tissue. The DNA content in laryngeal cancer increased distinctly, being much higher than that in normal and keratotic tissues.

DNA↗
PubMed1991

An experimental study on the laryngeal electromyography and visual observations in varying types of surgical injuries to the unilateral recurrent laryngeal nerve in the neck.

A series of varying types of surgical injuries to the recurrent laryngeal nerve, including half section, double crush, suture ligation, and complete section of the nerve, was investigated in dogs by correlating clinical and electromyographic findings. The state of recovery from palsy was evaluated by recording the electromyography from the affected laryngeal muscles as well as by observing the movements of the vocal cords. Six electromyography patterns were recorded from the affected muscles following injuries to the recurrent laryngeal nerve. There is a close relationship between the electromyography patterns and the types of nerve injuries. Within 3 months after injuries of the recurrent laryngeal nerve, the electromyography motor unit potentials in the involved intrinsic laryngeal muscles and vocal cord movements on the side of the nerve injury were back to normal in the groups of dogs in which the recurrent laryngeal nerves were partially sectioned and doubly crushed; the electromyography potentials and vocal cord motion on the affected side did not return to normal in the group of dogs in which the recurrent laryngeal nerves were permanently ligated with suture. In the group of dogs which had had a complete section of the recurrent laryngeal nerve, no recovery of both electromyography and vocal cord function on the affected side was observed 6 months after injury of the recurrent laryngeal nerve. This study showed that the frequency of the regenerated potentials recorded from the affected muscles is related to the types and degrees of injuries to the recurrent laryngeal nerve. Recovery from recurrent laryngeal nerve palsy is complete within 3 months after nerve impairment if over half of the nerve fibers of the impaired nerve are maintained intact without degeneration. Moreover, the period from onset to complete recovery from palsy was remarkably short, less than 2 months. The most appropriate time for the electromyography examination to evaluate the degrees of the nerve injury and to anticipate the prognosis of recurrent laryngeal nerve palsy was proposed.

Animals↗
PubMed1991

Afferent activity in the external branch of the superior laryngeal and recurrent laryngeal nerves.

We investigated the presence of respiratory-modulated receptors in the recurrent laryngeal nerve (RLN) and the external branch of the superior laryngeal nerve (ExtSLN) in anesthetized, spontaneously breathing dogs. Of 39 receptors recorded from the ExtSLN, the vast majority responded with a slowly adapting discharge to compression of the cricothyroid muscle, and only 1 responded to probing of the laryngeal mucosa. Ten receptors showed a respiratory modulation. All 30 receptors recorded from the RLN responded to probing of the laryngeal lumen, most of them (60%) with a rapidly adapting response. Seven of the slowly adapting receptors exhibited a respiratory modulation; 38% of the receptors tested were stimulated by water, and only 15% by smoke. No receptors stimulated by laryngeal cooling were identified in either nerve. Our study indicates that in the RLN and the ExtSLN there are relatively few afferents responding to changes in transmural pressure and mechanical irritation, as compared to the internal branch of the SLN. The relative scarcity of receptors responding to transmural pressure and irritant stimuli is consistent with previous observations in dogs that indicate a preponderant role for afferents in the internal branch of the SLN in the reflex responses to laryngeal stimulation.

Afferent Pathways↗
PubMed1992

[Laryngeal carcinoma with laryngeal abscess].

We had encountered 5 cases of laryngeal carcinoma associated with abscess. Four of them were advanced laryngeal cancer with abscess induced by mechanical injury, and one with post-radiation laryngeal perichondritis & abscess formation. Management included total laryngectomy in 3 patients, partial laryngectomy in 1 patient, and resection of post-radiation abscess in one. Laryngeal abscesses are seen rarely today. Endeavour should be made to decrease such complication. The authors had presented their experience in the management of laryngeal carcinoma associated with laryngeal abscess, together with a review of the history and some of the current ideas about this problem.

Abscess↗
PubMedDate not supplied

Observations on laryngeal disease, laryngeal behavior and voice.

This discussion accepted the hypothesis that every laryngeal sound is produced by its unique type of vocal cord vibration. The production of vocal sound is not capricious, it follows certain laws many of which are not known. Research into the behavior of the larynx has produced some interesting and perhaps, useful findings. It was the intention of this paper to describe some of the features of laryngeal behavior as they relate to both phonation and laryngeal disorders in the belief that such knowledge lends itself to the more efficient management of certain vocal and laryngeal problems. The central theme has been that it is laryngeal behavior and not laryngeal disease itself that determines vocal deviation.

Female↗
PubMed1992

[Selective laryngeal re-innervations in the dog by nervous microsutures of branches of the recurrent laryngeal nerve].

INTRODUCTION: This work has been carried out to investigate in an animal model, the possibility of surgical selective reinnervation of the larynx following destruction of the laryngeal branch of the vagus nerve. MATERIAL AND METHODS: In ten dogs, on the right side of the neck only, the recurrent laryngeal nerve was identified, cut and section of the nerve removed. Following this the hemi-larynx on the operated side was reinnervated in the following manner. Using a microsurgical suture (described in the text) the motor nerves from extra-laryngeal muscles were anastomosed onto the nerves supplying the intrinsic abductors and adductors of the larynx. The nerve to sterno-thyroid was anastomosed onto the nerve supplying the posterior crico-arytenoid muscle (vocal cord abductor). Similarly the nerve supplying thyrohyoid was anastomosed onto the cut distal end of the adductor division of the recurrent laryngeal nerve. Clinical, electromyographical and histological evaluations have been used to prove the reinnervation. RESULTS: In the nine surviving animals successful re-innervations, as defined by the return of normal function, has been achieved for posterior crico-arytenoid and 7 adductor muscles. CONCLUSION: This study has demonstrated the feasibility of laryngeal reinnervation after surgical section of the recurrent laryngeal nerve, and give some cause for optimism for its ultimate application in man.

Anastomosis, Surgical↗
PubMed1992

Laryngeal paralyses: theoretical considerations and effects on laryngeal vibration.

The neurological causes of vocal fold paralyses have been well documented. However, the effect of these disorders on laryngeal vibration is not well understood. A theoretical four-mass model of the larynx, based on the work of Ishizaka and Isshiki (1976) and Koizumi, Taniguchi, and Hiromitsu (1987), was developed and adapted to simulate laryngeal biomechanical behavior. The model was used to evaluate various states of asymmetric laryngeal vibration. Input parameters that relate observed laryngeal function and model simulation were developed. Laryngeal paralyses were simulated by their predicted effect on these parameters. Simulations were compared with available data on glottal vibration in laryngeal paralyses. Complex modes of vibration were seen with certain combinations of asymmetrical lower mass stiffness and initial glottal gap.

Computer Simulation↗
PubMed1990

Electronic control of laryngeal spasm. I. Blockage of orthodromically induced action potentials in intact canine recurrent laryngeal nerves.

Spastic dysphonia is a central nervous system phenomenon of unknown etiology characterized by uncoordinated voice tremor with erratic patterns of laryngeal contraction. Standard treatments have not been entirely satisfactory. The authors propose to apply a concept of selective nerve activity blockage, which leaves normal contractions undisturbed, as the basis for suppression of laryngeal spasticity. Single pulses of constant duration and increasing amplitude were injected into specially designed blocking electrodes placed around six recurrent laryngeal nerves (three dogs). Vocal cord adduction was reduced or arrested within given "windows" of stimulation levels of the blocking electrodes, while it increased with higher amplitudes when the current was injected via standard bipolar electrodes (controls). Although this study demonstrates the feasibility of blocking action potentials passing along recurrent laryngeal nerves, it might eventually allow control of laryngeal spasm from information taken directly from the affected musculature.

Action Potentials↗
PubMed1979

Changes in laryngeal motoneurone activity and in laryngeal calibre during the expiration reflex.

In anaesthetized and paralysed cats, the response of the laryngeal motoneurones during the expiration reflex is characterized by pronounced activation of the expiratory laryngeal motoneurones in the compressive phase and the subsequent constriction phase. In the expulsive phase the frequency of these discharges is significantly reduced. The inspiratory laryngeal motoneurones are inhibited during the reflex. The expiration reflex, in anaesthetized cats, is accompanied in the compressive phase and the subsequent constriction phase by a two-phase increase in laryngeal resistance. In the expulsive phase there is a significant drop in resistance.

Action Potentials↗
PubMed1989

[Reaction of the laryngeal mucosa and skin of the neck to the combined use of irradiation, hyperthermia and chemotherapy in laryngeal cancer].

Reactions of the laryngeal and neck skin mucosa were studied in 93 laryngeal cancer patients on combined therapy including hyperthermia. Patients in the control groups received no local hyperthermia. Reactions on the laryngeal mucosa (hyperemia, insular and confluent epitheliitis) were observed in all the patients; in patients receiving chemotherapy they were more noticeable. In patients receiving local hyperthermia these reactions appeared somewhat later and were less noticeable and not repeated. Skin reactions correlated only with a radiation dose and did not depend on chemotherapy and hyperthermia. Local electromagnetic hyperthermia in laryngeal cancer patients neither influenced the appearance of radiation reactions nor enhanced them.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

The responses of superior laryngeal nerve afferent fibres to laryngeal airway CO2 concentration in the anaesthetized cat.

In anaesthetized cats, the isolated, in situ, larynx was subjected to a simulated respiratory cycle and the responses of fifty-six superior laryngeal nerve (SLN) afferent fibres to respiration-related stimuli were examined during changes in the fractional CO2 concentration of the laryngeal airway (Faw, CO2). Sensory SLN fibres which displayed low rates of discharge when the larynx was unventilated (quiescent fibres) and which responded to negative laryngeal airway pressure were excited by elevations in Faw, CO2 whereas quiescent fibres responsive to positive laryngeal pressure were inhibited by the same procedure. We propose that changes in airway CO2 levels may play a role in maintaining upper airway patency, especially during sleep.

Anesthesia↗
PubMed1990

[Measurement of nuclear DNA content of laryngeal carcinoma and determination of estrogen receptor (ER) level in laryngeal cancer cells].

In 39 patients with laryngeal carcinoma, nuclear DNA content was measured, and the ER in cancer cells of 23 cases determined. The following results were obtained: 1. For all laryngeal carcinomas, there were two patterns-diploid and non-diploid carcinomas. The majority (27/39) belonged to the non-diploid pattern. 2. The laryngeal carcinomas of non-diploid pattern or with higher level of DNA content were easily metastasized to cervical nodes. This kind of cancers were more often seen in clinically advanced cases. Patients with these carcinomas, judged by the results of one-year's follow-up, had poor prognosis. 3. Carcinomas with diploid pattern or with lower level of DNA content had the tendency to become ER positive. The cervical node metastases was more easily taking place in ER negative carcinomas. Some indirect relationship between DNA content and ER in laryngeal cancers may exist.

Aneuploidy↗
PubMed1979

Local invasion by laryngeal carcinoma--the importance of focal (metaplastic) ossification within laryngeal cartilage.

Patterns of cartilage invasion by squamous carcinoma were examined in 34 consecutive laryngectomy specimens with particular reference to selective involvement of ossified cartilage. Direct infiltration of the laryngeal framework was demonstrated in 17 cases--16 (out of 17) transglottic carcinomas and in a simgle example of a combined glottic and infraglottic tumour. The susceptibility of ossified laryngeal cartilage to tumour invasion was confirmed, and morphological studies ahve clarified the underlying mechanisms. Invasion is a largely indirect process dominated by local bone destruction by osteoclasts, operating in front of the advancing tumour. One established, carcinoma cells infiltrate and erode bone alone, and the osteoclasts disappear. Reasons for the particular susceptibility of ossified laryngeal cartilage to tumour invasion are discussed and attention is drawn to the role of the tumour-associated osteoclast activating factors such as postaglandins. Therapeutic implications of cartilage invasion are noted.

Adult↗
PubMed1979

Asbestos fibers in laryngeal tissues. Findings in two patients with asbestosis associated with laryngeal tumors.

Significant concentrations of asbestos fibers have been found in samples of laryngeal tissue from two patients with past exposure to asbestos and associated asbestosis. In one case, there was a polyp on a vocal cord and in the other one a laryngeal carcinoma. These findings could provide an indication of a local carcinogenic effect of asbestos fibers in laryngeal tissue.

Adolescent↗
PubMedDate not supplied

AgNOR distribution in normal and dysplastic laryngeal mucosa and in laryngeal epidermoid carcinomas.

Samples of normal and dysplastic laryngeal mucosa and of laryngeal epidermoid carcinomas were submitted to the AgNOR silver staining technique. AgNORs were subdivided in large (LN) and small (SN) and counted separately along their sum (TN). Overlap of values is great between normal and mildly dysplastic mucosa and between moderate and severe dysplasia. Grouping together normal with mildly dysplastic mucosa, and moderate with severe dysplasia, their mean values show minimal overlap and the differences between them are highly significant. Plotting the mean values of these two groups and of carcinomas, the linear interpolations show a clearcut increase of values.

Carcinoma, Squamous Cell↗