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PubMed1991

Metalloproteinase digestion of cartilage proteoglycan. Pattern of cleavage by stromelysin and susceptibility to collagenase.

The action of purified rabbit bone stromelysin was investigated on proteoglycan aggregates from pig laryngeal cartilage. The enzyme caused a rapid fall in viscosity of proteoglycan aggregate solution (6 mg/ml), and the products of a partial digest (60% loss of relative viscosity) and a complete digest (95% loss of relative viscosity) were characterized. Analysis by gel chromatography on Sepharose 2B under associative conditions showed that 95% of the glycosaminoglycans in the complete digest were in small-sized fragments, whereas most of the hyaluronan-binding G1 domain and link protein remained intact and bound to hyaluronan. In contrast, there was extensive digestion of the G2 domain which resulted in 76% loss in its detection by immunoassay. Analysis of the partial digest also showed considerable loss (40%) of detection of the G2 domain, but the glycosaminoglycan-rich fragments were much larger than in the complete digest. There was also much less cleavage to create small fragments containing the G1 domain. This was evident on SDS/PAGE analysis where a 58 kDa G1 domain fragment was abundant in the complete digest, but was only present in small amounts in the partial digest. There was also only very limited conversion of link protein from a 44 kDa form to a 40 kDa form. The digestion of proteoglycan aggregate (6 mg/ml) by stromelysin was unaffected by the addition of a high concentration of extra chondroitin sulphate chains (14 mg/ml), and the digestion of proteoglycan monomer showed that the G1 domain was resistant to stromelysin digestion even when not bound to hyaluronan and link protein. The results show that stromelysin degrades the proteoglycan protein core with major cleavages close to, but not within, the G1 domain, and extensive cleavage in other regions. Experiments with purified collagenase, a metalloproteinase structurally related to stromelysin, showed that it too cleaved proteoglycan at several sites within the glycosaminoglycan-rich region of the core protein. Metalloproteinase attack on proteoglycan thus not only occurs with stromelysin but also with collagenase.

Animals↗
PubMed1979

Submucosal cordectomy for laryngeal stenosis.

Submucosal cordectomy, an old procedure first described for the treatment of bilateral abductor vocal cord paralysis, was used to relieve glottic or minimal subglottic stenosis in four patients. Three attained adequate airways with no further procedures; one required subsequent dilations for granulation tissue after which decannulation was successfully effected. Although airway restoration has been successful, the resultant voice has been poor, poorer than that usually achieved with arytenoidectomy. When cricoarytenoid scarring precludes arytenoidectomy and lateral vocal cord fixation, an adequate laryngeal lumen can be restored with submucosal cordectomy if sufficient laryngeal cartilage support remains.

Adolescent↗
PubMed1976

Cartilage proteoglycans. Structure and heterogeneity of the protein core and the effects of specific protein modifications on the binding to hyaluronate.

Purified proteoglycans extracted from pig laryngeal cartilage in 0.15 M-NaCl and 4 M-guanidinium chloride were analysed and their amino acid compositions determined. Selective modification of amino acid residues on the protein core confirmed that binding to hyaluronate was a function of the protein core, and was dependent on disulphide bridges, intact arginine and tryptophan residues, and epsilon-amino groups of lysine. Fluorescence measurement suggested that tryptophan was not involved in direct subsite interactions with the hyaluronate. The polydispersity in size and heterogeneity in composition of the aggregating proteoglycan was compatible with a structure based on a protein core containing a globular hyaluronate-binding region and an extended region of variable length also containing a variable degree of substitution with chondroitin sulphate chains. The non-aggregated proteoglycan extracted preferentially in 0.15 M-NaCl, which was unable to bind to hyaluronate, contained less cysteine and tryptophan than did other aggregating proteoglycans and may be deficient in the hyaluronate-binding region. Its small average size and low protein and keratan sulphate contents suggest that it may be a fragment of the chondroitin sulphate-bearing region of aggregating proteoglycan produced by proteolytic cleavage of newly synthesized molecules before their secretion from the cell.

Amino Acids↗
PubMed2005

Medialization thyroplasty window creation using an ultrasonic surgical aspirator.

OBJECTIVES/HYPOTHESIS: The aim of the study was to investigate the use of an ultrasonic surgical aspirator for creation of the laryngeal cartilage window during medialization thyroplasty. STUDY DESIGN: Basic science. METHODS: Forty thyroplasty windows were constructed in fresh, unpreserved cadaver larynges. A 6 x 13-mm rectangular window and a 4 x 4-mm round window were created on each side of the larynges in a symmetrical fashion. A standard surgical drill with a 3-mm cutting burr was used on one side; the ultrasonic surgical aspirator was used on the contralateral side. The time required for window construction was recorded, as was the status of the inner perichondrium at window completion. RESULTS: For creation of the 6 x 13-mm window, a mean time of 128 seconds was required using a standard surgical drill. The mean time using the ultrasonic aspirator device was 91 seconds for the window of the same size (P < .008). For the 4-mm round window, drilling completed the task in a mean time of 63 seconds, compared with 40 seconds (P < .016) for the ultrasonic aspirator. On creation of the 6 x 13-mm window, there were 4 of 10 perichondrial violations in the drilled specimens, and there were no violations in creation of the window of the same size with the ultrasonic aspirator (P = .12). The 4-mm round window had no perichondrium violations in the standard drill group and only 1 of 10 violations in the ultrasonic aspirator group (P = .99). CONCLUSION: The study suggested that the ultrasonic surgical aspirator device may be an effective, efficient alternative to the standard drill for medialization thyroplasty window creation. Prospective clinical trials are warranted to better characterize its applicability.

Female↗
PubMedDate not supplied

Computerized axial tomography in the assessment of thyroid cartilage invasion by laryngeal carcinoma: a prospective study.

The purpose of this study was to assess the value of computerized axial tomography (CAT) in canine larynges that exhibit controlled surgical defects, and in 18 patients with biopsy-proved epidermoid carcinoma of the larynx who were studied prospectively. Five canine larynges with sequential surgical defects of 0 mm, 5 mm, 10 mm, and 15 mm were studied by CAT in order to evaluate our ability to identify defects in the thyroid cartilage. A 5-mm collimator with overlapping sections at 3-mm intervals and a 13-mm collimator with 5-mm overlapping sections were both used for each stage of the experiment. Results show significantly improved resolution with the 5-mm collimator compared with the 13-mm unit. In the human study group, results demonstrated excellent (100%) soft-tissue tumor site correlation. It appears from this study that we still lack a highly reliable radiographic technique for evaluating preoperatively with accuracy the integrity of the thyroid cartilage in the patient with carcinoma of the larynx.

Animals↗
PubMed1993

Three-dimensional analysis of murine laryngeal development.

This study defines the critical stages in the prenatal development of the mouse larynx. Three-dimensional computer-generated solid model reconstructions display the changing anatomic relationships during laryngeal development from the earliest respiratory primordium to the mature laryngeal vestibule. These reconstructions demonstrate that the laryngeal vestibule forms as a result of a cephalocaudal separation of the epithelial lamina, thereby establishing communication between the laryngeal cecum and the pharyngoglottic duct. These results support the hypothesis that the cause of congenital supraglottic and glottic malformations is an incomplete separation of this epithelial lamina. The infraglottic lumen remains patent during laryngeal development. Continued lengthening of the foregut between the infraglottis and the carina forms the trachea. This is contrary to the 19th-century concept of an ascending tracheoesophageal septum. Formation of the laryngeal cartilages, muscles, and innervation is portrayed by the reconstructions; with minor variations, they correlate closely with earlier wax reconstructions of human laryngeal development. Future research with this animal model can provide additional insights into the complex mechanisms involved in congenital malformations of the larynx.

Animals↗
PubMed1978

Evaluation of laryngeal cancer by computed tomography.

Six cases of laryngeal cancer have been examined by computed tomography. The findings were correlated with those obtained by laryngoscopy and in five cases by pathological examination of the surgical specimens. Computed tomography accurately delineated the extent of tumor involvement of the laryngeal and paralaryngeal soft tissues. The diagnosis of involvement of the laryngeal cartilages presents some problems, which are discussed.

Aged↗
PubMed2006

Placement of a long term tracheal cannula in a Thoroughbred racehorse with bilateral laryngeal dysfunction.

A Thoroughbred horse with bilateral laryngeal dysfunction was treated by placement of a long term tracheal cannula in order to restore full athletic function. The horse initially presented with right-sided arytenoid dysfunction that was considered to be due to a congenital malformation of the laryngeal cartilage. This was corrected by a right-sided laryngoplasty and ventriculectomy. The horse re-presented 1 year later with idiopathic left laryngeal hemiplegia. The decision was made to place a long-term tracheal cannula due to the low success rate and high complication rate associated with other surgeries used to correct bilateral arytenoid dysfunction. A three-piece tracheotomy cannula and stopper were positioned under general anaesthesia. The horse rapidly adjusted to the tracheal cannula and no post-surgical complications were encountered. The horse resumed training 4 weeks postoperatively. Due to the rules governing racing in Australia the horse was exported to New Zealand where he continued his racing career. It was concluded that tracheotomy is a straightforward technique associated with minimal complications and can provide an excellent prognosis for return of full airway function in racing horses. It is recognised that many issues need to be considered prior to more general acceptance of this technique, including assessment of animal welfare issues and public perception. In appropriate cases consideration should be given to using long term placement of a tracheotomy cannula as a treatment option to restore maximal airflow in horses with upper airway obstruction.

Animals↗
PubMed1989

Osteosarcoma of the larynx.

A case of laryngeal osteosarcoma in a 75-year-old man is described. The osteosarcoma probably arose by dedifferentiation of a chondrosarcoma of the cricoid cartilage. Laryngeal osteosarcoma is rare: the literature is reviewed and management discussed.

Aged↗
PubMed1998

[Stroboscopy and imaging in interdisciplinary diagnosis of early stages of laryngeal carcinoma].

The laryngostroboscopy is regarded to be the most important functional investigation in laryngologic and phoniatric diagnostics. She allows an analysis of vocal fold vibrations during phonation. Stroboscopic evaluations permit to early detect infiltrative processes of the vocal folds. Superficial alterations of the mucous membrane that invade into the muscle cause a phonatory "standstill" of the vocal fold in the stroboscopy, i.e. a complete lack of vibratory motion. If such a phonatory standstill persists for more than 2 or 3 weeks, a biopsy via microlaryngoscopy is indicated for diagnostic purposes. In comparison to stroboscopy, imaging techniques are not of such great significance in early laryngeal cancer. But in case of suspected infiltration of the tumor a further diagnostic evaluation with CT or MRI is necessary to detect possible neoplastic invasion of the laryngeal cartilage or of extralaryngeal structures. In this paper, we present the principle of laryngostroboscopy, the examination procedure and the stroboscopic parameters. Case reports of early laryngeal cancer illustrate the interdisciplinary diagnostic procedure with CT, MRI and stroboscopy.

Adult↗
PubMed1990

[Chondroma of the larynx--case report and differential diagnosis in CT].

The characteristic features of chondroma and chondrosarcoma of the larynx (less than 1% of laryngeal tumors) are discussed in a case report. Laryngoscopy (rounded, smooth tumor, covered by normal mucous membrane) and HR-CT of the larynx (swelling of the cartilages, calcifications in 80% of cases) give a characteristic view of the tumor, so that, by synopsis of both, a definite diagnostic statement concerning the kind of tumor is possible. However, carcinoma of the larynx with invasion of the cartilage, laryngeal manifestation of multiple chondromatosis and calcification after severe trauma have to be differentiated from cartilaginous tumors of the larynx. The adequate therapy of chondroma and low-grade chondrosarcoma consists of partial laryngectomy and reconstruction of the air passages. High-grade chondrosarcoma should be treated with radical laryngectomy.

Chondroma↗
PubMed1990

MR findings of cartilage invasion by laryngeal cancer: value in predicting outcome of radiation therapy.

Thirty-nine patients who underwent radiation therapy with curative intent for laryngeal cancer were examined before treatment with magnetic resonance (MR) imaging, between November 1985 and January 1987. MR findings of cartilage invasion were correlated with the effectiveness of radiation treatment. Adequate interpretation of the MR examinations was not possible in four cases (10%). Cartilage invasion was found in 16 of the 35 remaining patients and was found even in small glottic lesions, clinically staged as T1b and T2. Laryngeal cancer recurred in 10 of the 16 patients with cartilage invasion shown by MR imaging. The presence of even small foci of invasion of the thyroid cartilage by laryngeal cancer appeared to increase the subsequent risk of tumor recurrence. Cartilage invasion seen at MR imaging might therefore shift the preference to partial laryngectomy as the initial treatment for small glottic tumors. Alternatively, radiation therapy alone would appear to require stringent follow-up to detect possible recurrence.

Adult↗
PubMedDate not supplied

Computed tomography in determining laryngeal involvement of hypopharyngeal carcinoma.

In 22 patients with hypopharyngeal carcinoma, the extent of laryngeal involvement was estimated preoperatively by means of computed tomography and visual inspection including mirror examination and fiberscopic and strobofiberscopic video recordings. All patients underwent laryngopharyngectomy, and the surgical specimens were subjected to a whole organ section study. The results of the preoperative evaluations were related to the histopathologic findings. Computed tomography was reliable for the estimation of paraglottic space involvements. It was also useful in detecting carcinomatous invasion into the preepiglottic space and aryepiglottic fold, but there were some false positives for these structures. It was not always reliable in assessing invasion of the laryngeal cartilages. It provided a very accurate estimation of involvement for the thyroarytenoid muscle and a considerably accurate assessment for the lateral cricoarytenoid and interarytenoid muscles and the recurrent laryngeal nerve. It was useful in detecting involvement of the posterior cricoarytenoid muscle, but there were a fair number of false positives. For the cricothyroid muscle, the estimation based on CT was not very reliable. Some erroneous judgments on CT were corrected in a comprehensive evaluation that included visual inspection.

False Negative Reactions↗
PubMed1984

Metastasis to the larynx from a prostatic carcinoma. A case report.

We present the fourth reported case of metastases of adenocarcinoma from the prostate to the larynx. The patient was a 64-year-old male who presented with stridor from a smooth subglottic mass six months after he had been diagnosed as having adenocarcinoma of the prostate with bone secondaries. We have reviewed the mechanisms by which such a tumour might metastasize to the larynx and we feel that ossification in the laryngeal cartilages may be important in the development of such metastases.

Adenocarcinoma↗
PubMed2005

Late laryngeal radionecrosis in severe arteriosclerosis.

Laryngeal necrosis is a serious complication that usually occurs within the first year following completion of radiotherapy, although it is reported that cases can develop after a long period of latency. Factors such as dosage and irradiation technique employed, tumour invasion into the laryngeal cartilage, infection, continued smoking, trauma and general vascular condition of the patient have been considered to increase the rate and degree of development of radionecrosis. We report an unusual case of laryngeal radionecrosis in a patient with hypertension, hyperlipidaemia, diabetes and a history of cigarette smoking, which developed 25 years after radiotherapy for laryngeal carcinoma. His systemic illnesses and continued smoking were speculated to have contributed to the progress of the radionecrosis, suggesting that cessation of smoking and control of arteriosclerotic diseases should be considered to decrease its incidence.

Aged↗
PubMed1991

[Spin-echo anatomy of the larynx with magnetic resonance at 1.5 T].

The larynges of 8 healthy and informed volunteers were studied with a superconductive MR unit at 1.5 T together with those of 10 patients with extralaryngeal pathologic conditions. The study was performed with round surface coils (5") and with dedicated sellar coils in the anterior neck. Slices were 5 mm thick, and acquired on the coronal, axial, and sagittal planes, with T1-weighting; axial scans were repeated in the same locations with double echoes, with proton-density and T2-weighting. Five patients underwent additional scans after Gd-DTPA. The larynx of a semi-frozen cadaver was examined with sellar surface coils, on similar scanning planes and with similar pulse sequences to those described above; the larynx was removed, investigated with mammographic technique, and subsequently analyzed with thin CT slices and a high-resolution reconstruction algorithm for the study of laryngeal cartilage. Axial anatomical sections were then compared with MR and CT scans, and the anatomical structures were recognized on the triplanar MR scans of a volunteer's larynx. Besides MR anatomy of supporting laryngeal structures, the authors describe in detail the muscles, plicae, spaces and cavities which can be identified on the various planes, together with the changes in signal after Gd-DTPA.

Contrast Media↗
PubMedDate not supplied

Role of vertical larynx movement and cervical lordosis in F0 control.

The role of vertical larynx movement in vocal frequency (F0) change has attracted the attention of many researchers. Recently, Hirai, Honda, Fujimoto, and Shimada (1994) proposed a mechanism of F0 control by vertical larynx movement based on the measurement of magnetic resonance images (MRI). In F0 changes, the larynx moves vertically along the cervical spine, which displays anterior convexity (lordosis) at the level of the larynx. Therefore, the vertical larynx movement results in the rotation of the cricoid cartilage and vocal fold tension changes. The present study reexamines the above mechanism based on a qualitative analysis of midsagittal MRI data using three male subjects with evident cervical lordosis. Tracings of the jaw, hyoid bone, laryngeal cartilage, and cervical spine were compared in high and low F0 ranges. In the high F0 range, the hyoid bone moved horizontally while the larynx height remained relatively constant. In the low F0 range, the entire larynx moved vertically, and the cricoid cartilage rotated along the cervical lordosis. These results indicate that the vertical movement of the larynx comprises an effective F0 lowering mechanism, and suggest that the human morphologies of low larynx position and spinal curvature contribute to voluntary use of the vocal function.

Cervical Vertebrae↗