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Biomedical subjects

T V McCaffrey

Publications and source records attributed to T V McCaffrey.

At least 19 recordsLinked to original sources
PubMed1992

Study of vibratory pattern of the vocal folds in the excised canine larynx.

The effect of simulated thyroarytenoid and cricothyroid muscle contraction on the vibratory pattern of the vocal folds was studied in the excised canine larynx. To simulate the action of the thyroarytenoid muscle, small balloons were inflated in the paraglottic space at the level of the vocal folds. To simulate the action of the cricothyroid muscle, longitudinal tension was applied to the anterior commissure of the vocal folds. The photoglottographic and electroglottographic signals, sound intensity, and airflow rate were measured. This study showed that balloon inflation simulating thyroarytenoid muscle contraction produced an elevation of frequency of vibration with a decrease in open quotient, and that an increase in longitudinal tension simulating cricothyroid muscle contraction produced an elevation of frequency with an increase in open quotient. Vocal resistance decreased with increasing open quotient, amplitude of the photoglottographic waveform, and the frequency of vibration. Vocal efficiency increased with increasing photoglottographic amplitude and decreased with increasing frequency. The vocal efficiency peaked when the open quotient was approximately 0.5. This study suggests that glottographic parameters may be useful in assessing the effect of intrinsic laryngeal muscle activity on vocal efficiency and glottic resistance.

Animals↗
PubMed1992

The effect of tissue expansion on previously irradiated skin.

Opinion remains divided over the advisability of tissue expansion in previously irradiated skin. We examined the properties of, and complications associated with, tissue expansion in previously irradiated rabbit scalps. Irradiation injury was produced using fractionated roentgen rays, with a total dose of 5000 cGy over a 5-week interval. Following a 20-week convalescence interval, expansion was incrementally conducted over 4 weeks. Monitored parameters included cutaneous perfusion as indicated by fiberoptic dermofluorometry, intraluminal pressure, linear surface gain, and area of surface necrosis. The incidence and severity of complications, including surface necrosis, were significantly higher among irradiated animals. Furthermore, the overlying skin of irradiated animals demonstrated a significantly decreased compliance and measurable area gain. Given the inferior expansibility and higher tendency toward complications with contemporary expansion techniques in previously irradiated skin, alternate reconstructive options are preferable in this setting.

Animals↗
PubMed1992

Head and neck cancer surgery.

This review presents several areas of current interest in head and neck oncology including endoscopic and conservation management of early laryngeal cancer, intraoperative radiotherapy, and microvascular reconstruction techniques. Endoscopic treatment of early laryngeal cancer using the CO2 laser has been shown to be effective in several recent studies, and improved laryngeal reconstruction techniques following conservation laryngeal surgery have resulted in improved functional results. Intraoperative radiotherapy for head and neck carcinoma has received more attention recently, with encouraging results for the treatment of advanced and recurrent skull base and head and neck tumors. New techniques of free flap reconstruction following surgery for head and neck cancer continue to result in improved rehabilitation.

Clinical Trials as Topic↗
PubMed1992

Noninvasive technique for estimating subglottic pressure and laryngeal efficiency.

The clinical assessment of aerodynamic parameters is important in the physiology and pathophysiology of laryngeal function. Vocal efficiency is among these objective measurements and can be calculated from simultaneous recordings of subglottic pressure, airflow, and sound intensity. Modern techniques allow us to accurately determine sound intensity and airflow. However, methods to determine subglottic pressure are either invasive or laborious. We have evaluated a noninvasive, indirect method to determine subglottic pressure by using a technique based on the interruption of transglottic airflow during phonation. The correlation between the indirectly acquired subglottic pressure measured in the oral cavity by using this technique and the subglottic pressure obtained directly by translaryngeal puncture in human volunteers was highly significant in 35 trials (r = .92, p less than .01). This study describes a reliable technique for the noninvasive measurement of subglottic pressure, sound intensity, and airflow.

Glottis↗
PubMed1992

Early mucosal changes in experimental sinusitis.

Normal mucociliary flow is a significant defense mechanism in the prevention of acute sinusitis. We have undertaken a study to examine the early sinus mucosal and mucociliary changes that occur in response to acute infection. Twenty rabbits were evaluated for 5 days after an obstructed maxillary sinus was inoculated with either Streptococcus pneumoniae, Hemophilus influenzae, Pseudomonas aeruginosa, or a sterile saline solution. Data collected included measurements of sinus mucosal ciliary beat frequency, quantitation of ciliated cell losses, and electron microscopic observations. Results demonstrate statistically significant (p < 0.05) changes in mucosal ciliary beat frequency that were either excitatory or inhibitory, depending both on the length of the infection and the specific organism. No changes in ciliary beat frequency were observed in the control animals (p > 0.55). Control animals likewise demonstrated no loss of ciliated cells from mucosal epithelium; however, dramatic losses of ciliated cells from the sinus mucosa of the experimental groups were observed. These losses occurred at different rates, depending on the infecting organism, but all infected groups demonstrated a > 86% decrease in the number of viable ciliated cells from the sinus mucosa after sinusitis of 5 days duration. We conclude that a significant loss of ciliated cells from sinus mucosa and a corresponding disruption of normal mucociliary flow occurs early after exposure to pathogenic organisms and is a significant predisposing factor in the development of acute sinusitis.

Animals↗
PubMed1992

Effect of substance P on ciliary beat frequency in human adenoid explants.

This study investigated the direct effects of substance P (SP) on ciliary beat frequency of human upper airway mucosa. Human adenoid explant tissue was maintained in serum free culture media, MCDB153. Ciliated epithelial cells were observed with phase-contrast microscopy and ciliary activity was measured using a photometric technique. Oscillations in transmitted light caused by ciliary beating were recorded and modal ciliary beat frequency was determined by fast Fourier transformation. Specimens were treated with SP at concentrations of 10(-4), 10(-5), 10(-6), and 10(-7) mol/L and with equal molar solutions of SP and (D-Pro2,D-Trp7,9)-SP, a SP antagonist. Substance P was found to increase ciliary beat frequency in a dose-dependent manner with a maximum increase of 12.1%. This effect was not seen with solutions containing (D-Pro2,D-Trp7,9)-SP. This suggests that SP exerts a direct stimulatory effect on ciliated cells of the upper airway. Because SP is known to be released in the upper airway in response to chemical irritation, it is presumed that the stimulatory effect of SP on mucosal cells provides a protective mechanism against inhaled irritants.

Adenoids↗
PubMed1992

Classification of laryngotracheal stenosis.

Seventy-two cases of laryngotracheal stenosis treated from 1981 through 1991 were reviewed to develop a system of classification which would be useful in predicting the outcome of treatment. Decannulation and absence of dyspnea after exertion were the criteria of successful management. The probability of decannulation over time was computed using the Kaplan-Meier technique. Cox multiple regression analysis was used to determine the effects of independent variables (age, sex, etiology, site of stenosis, length of stenosis, diameter of stenosis, and surgical technique) on treatment success. The only factors with a significant effect on the outcome were site of stenosis and diameter of stenosis. A classification into four clinical stages of stenosis based on site of lesion was shown to effectively predict the likelihood of successful decannulation.

Adolescent↗
PubMed1992

The effect of arachidonic acid metabolites on the ciliary beat frequency of human nasal mucosa in vitro.

Using computerized microphotometry, we studied the effects of prostaglandin E2 (PGE2), the prostacyclin analog Iloprost, and the thromboxane A2 analog U46619 on the ciliary beat frequency (CBF) of human nasal mucosa. Thirty-two normal subjects underwent nasal cytologic brushing of the inferior meatus to obtain ciliary samples, and a total of 5,640 ciliated cell clusters were analyzed. Each subject served as their own control. PGE2, 10(-10) to 10(-6) M, produced a significant dose dependent increase in CBF of up to 12% versus control. This increase was not significantly inhibited by the addition of the cyclooxygenase inhibitor indomethacin (10(-6) M). Iloprost, 10(-12) to 10(-6) M, also significantly increased CBF by 12.7% at 10(-8) M. This ciliostimulatory effect, however, was abolished by indomethacin. The thromboxane A2 analog, 10(-10) to 10(-6) M, did not significantly effect CBF. The present study demonstrates that a thromboxane A2 analog has no effect on ciliary motility, PGE2 has a direct ciliostimulatory effect, and a prostacyclin analog has a ciliostimulatory effect likely mediated by stimulation of the cyclooxygenase pathway within human cells.

Cell Movement↗
PubMed1991

Primary parotid malignancies. A clinical and pathologic review.

One hundred ninety-four patients with primary malignant tumors of the parotid gland who underwent surgery at the Mayo Clinic (1970 through 1987) are reviewed. Survival patterns were analyzed using the Kaplan-Meier product-limit method that separated histologic results into three significantly different groups. Survival rate was highest for patients with acinic cell, adenoid cystic, and low-grade mucoepidermoid carcinomas; intermediate for patients with high-grade mucoepidermoid carcinomas; and lowest for the remaining six histologic types encountered. Cox multiple linear regression was used to identify patient and tumor characteristics with greatest prognostic significance. In order of decreasing strength, regional metastatic involvement, pain, male gender, grade, stage, and advancing age all demonstrated independent prognostic significance. Fifty-three percent of patients requiring facial nerve sacrifice were asymptomatic at presentation. A high positive correlation was observed between advancing grade and stage.

Adolescent↗
PubMed1991

Surgical treatment in head and neck cancer.

Three topics currently important in head and neck surgery are voice-conserving surgical treatment of laryngeal cancer, the role of modified radical neck dissection in the treatment of cervical metastases, and reconstruction and rehabilitation of the head and neck cancer patient. The laser has become an accepted modality for the treatment of early vocal cord cancer and has local control rates comparable to other treatment methods. Partial laryngectomy can conserve voice and yield excellent local control rates. The modified radical neck dissection has been shown to yield rates of local recurrence no greater than radical neck dissection for N0 and N1 neck disease associated with laryngeal cancer. Vocal rehabilitation following total laryngectomy has been revolutionized by the tracheoesophageal puncture procedure. Most patients can be expected to acquire voice using tracheoesophageal puncture following total laryngectomy. Free flaps have improved the functional results of many major head and neck surgical procedures and offer the possibility of better results in the future. However, more conventional reconstructive techniques, including local flaps, continue to have a role in head and neck surgery.

Head and Neck Neoplasms↗
PubMed1991

Management of subglottic stenosis in the adult.

Twenty-one adult patients were surgically treated for severe subglottic stenosis refractory to endoscopic treatment. Patients were treated by anterior or anterior and posterior cricoid division with costal cartilage grafting. Seventy-six percent of the patients were successfully decannulated. Success of treatment was not dependent on cause of the stenosis or age or sex of the patient. There was a significantly better outcome (p less than .05) in patients with isolated subglottic stenosis versus those with combined glottic and subglottic stenosis.

Adolescent↗
PubMed1991

Regulation of phonatory efficiency by vocal fold tension and glottic width in the excised canine larynx.

An excised canine larynx was used to assess the effects of glottic width and vocal fold tension on acoustic power, aerodynamic power, and vocal efficiency. Multiple regression analysis of the data obtained from 10 larynges revealed that with increased vocal fold tension there is a logarithmic decline in radiated acoustic power, while aerodynamic power remains constant (p less than .05). Vocal efficiency has a similar logarithmic decrease with increased tension (p less than .05). With narrowing of the glottis, the acoustic power increases more than the aerodynamic power delivered to the larynx, and the efficiency increases. The inverse relationships glottic width has with acoustic power and vocal efficiency are best described by a reciprocal model (p less than .01). There is a negative linear relationship between glottic width and aerodynamic power. These results suggest that within the larynx the energy conversion is regulated by glottic aperture and longitudinal vocal fold tension. The optimal width for efficiency appears to be the narrowest width that produces phonation within the modal register, whereas increased tension decreases the efficiency of the glottis.

Animals↗
PubMed1991

Study of phonation in the excised canine larynx.

Previous studies have demonstrated that the laryngeal muscles responsible for pitch variation and vocal efficiency are the cricothyroid muscles, affecting longitudinal tension of the vocal folds, and the thyroarytenoid muscles, controlling the lateral stiffness of the vocal folds. Longitudinal tension in the vocal fold is easily simulated in the excised canine larynx. The effect of the thyroarytenoid muscle, however, has not been adequately analyzed. To simulate the effect of the thyroarytenoid muscle, small balloons were placed in the paraglottic space at the level of the vocal folds in 10 excised canine larynges. These balloons (Fogarty catheters) could be inflated in increments to simulate the effect of the thyroarytenoid muscle contraction in altering the lateral stiffness of the vocal fold. During phonation subglottic pressure, vocal fold longitudinal tension and balloon size were systematically varied. The photoglottographic and electroglottographic signals, sound intensity, and airflow rate were measured. Multiple regression analysis showed that sound intensity was directly related to subglottic pressure (p less than 0.001) and inversely related to balloon size (p less than 0.001). Vocal efficiency was directly related to subglottic pressure (p less than 0.001). Frequency of vibration was directly related to balloon size (p less than 0.05), vocal fold tension (p less than 0.001), and subglottic pressure (p less than 0.001). Open quotient was directly related to vocal fold tension (p less than 0.01) and inversely related to balloon size (p less than 0.001). Clinical implications of these results will be discussed.

Animals↗
PubMed1991

Effect of superior laryngeal nerve on vocal fold function: an in vivo canine model.

Assessment of laryngeal framework surgery requires an awareness of the effect of vocal fold mass, stiffness, and position on voice production. The vibratory pattern of vocal folds during phonation depends on the subglottic pressure as well as the mass and stiffness of the folds. To assess the effect of variations in vocal fold tension with contraction of the cricothyroid muscle on phonation, eight mongrel dog larynges were studied in vivo. Photoglottography, electroglottography, and subglottic pressure were simultaneously recorded as airflow rate and superior laryngeal nerve (SLN) stimulation were varied. Stimulation of the SLN was modified by varying the frequency and voltage of the stimulating electrical signal. Multiple regression analysis of the data revealed a direct relationship between the voltage of SLN stimulation and frequency of vibration (p less than 0.001) at constant subglottic pressure. Increases in the stimulating voltage to the SLN also led to an increase in open quotient (p less than 0.001), but no statistically significant change in speed quotient, subglottic pressure, or sound intensity. Changing the frequency of SLN stimulation had only a modest effect on the frequency of vibration. These results are consistent with the reported findings of an increase in frequency and open quotient with increased tension in an in vitro canine model. The glottographic measurement open quotient appears to be an estimator of cricothyroid contraction and longitudinal vocal fold tension, and may be clinically applicable to the assessment of superior laryngeal nerve injuries and laryngeal framework procedures.

Animals↗
PubMed1990

Glottographic analysis of phonation in the excised canine larynx.

An excised canine larynx model of phonation was developed to assess the effect of vocal fold length and tension on glottographic waveforms. The canine larynx in an experimentally produced phonatory model vibrated in a two-mass system comparable to human voice production. The recorded glottographic waveforms for the excised canine larynx were similar to signals recorded in humans in the chest register. Vocal fold length, longitudinal vocal fold tension, glottic width, and airflow rate were varied while simultaneous measurements were made of the subglottic pressure, electroglottographic signal, photoglottographic signal, and acoustic signal. The model used is illustrated and discussed, with emphasis on the method of simulating the actions of all of the intrinsic laryngeal muscles, including the thyroarytenoid muscles. The open quotient and speed quotient, calculated from the glottographic signals, were dependent on vocal fold length and tension and glottic width. These results suggest that glottographic analysis, particularly speed quotient and open quotient, provide valuable information on vocal fold vibration during phonation, and may be important in assessing laryngoplasty procedures.

Animals↗
PubMed1990

Effect of Klebsiella ozaenae on ciliary activity in vitro: implications in the pathogenesis of atrophic rhinitis.

Klebsiella ozaenae is a gram-negative rod that has been isolated with relative frequency from patients with atrophic rhinitis. The relationship of this bacterium to the pathogenesis of atrophic rhinitis is not understood, and whether this bacterium is simply an opportunistic colonizer of the injured nose or the etiologic agent of the disease is unclear. This study was designed to investigate a potential role for bacterially produced cilioinhibition as a mechanism for the pathogenesis of atrophic rhinitis.

Cilia↗