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At least 217 records · Page 12Linked to original sources
PubMed1991

Neuromuscular effects of succinylcholine on the vocal cords and adductor pollicis muscles.

To quantify the effects of succinylcholine at the laryngeal adductor muscles and the adductor pollicis, 17 adult patients were studied during propofol-fentanyl anesthesia. Train-of-four stimulation was applied to the ulnar nerve at the wrist and the recurrent laryngeal nerve at the notch of the thyroid cartilage. Laryngeal response was measured as pressure changes in the cuff of the tracheal tube positioned between the vocal cords. The force of contraction of the laryngeal adductor muscles and of the adductor pollicis were compared after administration of 0.25 or 0.5 mg/kg of succinylcholine. With 0.25 mg/kg, maximum blockade of first twitch (T1) was 66% +/- 10% (mean +/- SEM) and 45% +/- 13% at the vocal cords and the adductor pollicis, respectively (P less than 0.01). After 0.5 mg/kg, maximum blockade at the vocal cords (93% +/- 2%) and the adductor pollicis (84% +/- 6%) did not differ significantly. For both doses, time to maximal blockade was shorter for the vocal cords (0.9 +/- 0.1 min) than for the adductor pollicis (1.7 +/- 0.2 min; P less than 0.01). Time to 90% recovery of T1 after a bolus of 0.5 mg/kg was similar at the vocal cords (4.3 +/- 0.5 min) and the adductor pollicis (5.2 +/- 0.8 min) (NS). The ED50 was less at the laryngeal adductors (0.170 mg/kg) than at the adductor pollicis (0.278 mg/kg). It is concluded that, in adults, succinylcholine-induced blockade is more rapid and more intense at the laryngeal muscles than at the adductor pollicis.

Adolescent↗
PubMed1982

Ossification of the laryngeal, tracheal and syringeal cartilages in the domestic fowl.

The process of ossification in the cartilages of the larynx, trachea and syrinx of the domestic fowl has been studied in growing and in adult Golden Comet birds. In the laryngeal cartilages, mineralisation occurred consistently in the body and wings of the cricoid cartilage, in the procricoid cartilage and in the bodies of the arytenoid cartilages. In 7 out of 12 adult birds there were small additional centres in the tips of the rostral processes of the arytenoid cartilages and in one adult bird there were small centres in the caudal processes also. When present, these additional centres were always found bilaterally. Mineralisation in the laryngeal cartilages developed from 105 days post-hatching onwards and was first seen in the bodies of the arytenoid cartilages. Some evidence of a segmental pattern was noted, both in the earliest centres and in the final stage in the caudal region of the body of the tcricoid cartilage. Mineralisation in the trachea developed from 98 days post-hatching onwards. It was first found in the caudal region and spread craniad. The rings at the caudal end of the trachea and the cranial end of the tympanum (but not the last two rings of he tympanum) were always fully involved. Rings in the cranial part of the trachea remained more lightly mineralised. In the syrinx, mineralisation regularly occurred only in the pessulus and in the base of the first bronchial syringeal cartilages. In some birds, it was also encountered more caudally in the cartilages of the primary bronchi. Histological examination showed that, in the early stages, the alizarin staining was due to the presence of mineralised cartilage. At 182 days post-hatching and in the adults, actual bony tissue was observed. The possible significance of the occurrence of ossification in these cartilages of birds in briefly considered.

Animals↗
PubMed1998

Implications of cartilage invasion in surgically treated laryngeal carcinoma.

BACKGROUND: Cartilage invasion adversely affects the outcome of laryngeal carcinoma treated with radiotherapy. The UICC and American Joint Committee on Cancer (AJCC) classify laryngeal carcinoma with cartilage invasion as T4 or stage IV. METHODS: This study examines the prognostic significance of cartilage involvement in T3,4 N0,1 glottic carcinoma treated with total laryngectomy. Patients with tumor extension to pharynx, tongue, and thyroid gland, extracapsular spread, positive resection margins, and less than 2 years' follow-up were excluded. RESULTS: Sixty-seven pT3 (cartilage free of tumor) and 37 pT4 (cartilage invaded by tumor) cases were studied. The difference between the pT3 and pT4 groups in terms of local or regional recurrence, distant metastasis, and determinate survival was not significant. CONCLUSIONS: The results of this study question the use of cartilage invasion as a staging parameter for surgically treated laryngeal carcinoma. However, further studies with larger sample sizes are required to fully elucidate the prognostic significance, if any, of cartilage invasion in surgically treated cancer of the larynx.

Aged↗
PubMed1977

Synthesis of proteoglycans by suspension and monolayer cultures of adult chondrocytes and de novo cartilage nodules-the effect of hyaluronic acid.

Chondrocytes were isolated from adult laryngeal cartilage by an enzymic procedure that included 6 h digestion with collagenase. The level of 35SO4(2-) incorporation into cetylpyridinium chloride-precipitable material by these cells depended upon the subsequent culturing conditions. Suspension cultures incorporated more 35SO4(2-)/cell than monolayer cultures. Hyaluronic acid in the medium inhibited 35SO4(2-) incorporation only when the cells were in primary suspension cultures. It had no effect on monolayer cultures, or monolayers organized into nodules, or suspension cultures derived from monolayers. Mild pretreatment with EDTA, however, rendered these susceptible to hyaluronic acid inhibition. In contrast EDTA abolished the inhibitory effect of hyaluronic acid on primary suspension cultures. Oligosaccharides, derived from hyaluronidase digestion of hyaluronic acid that were larger than decassaccharide, had some inhibitor effect on 35SO4(2-) incorporation by monolayer cultures. The total 35SO4(2-) incorporation was less in primary suspension cultures of chondrocytes isolated after 12 h than after 6 h digestion of cartilage and the inhibition by hyaluronic acid was also less. These differences persisted during 12 days of culture. It is suggested that the method of isolating chondrocytes and subsequent culture conditions may modify the cell surface and mask or abolish specific binding sites for hyaluronic acid.

Animals↗
PubMed1985

Structure and interactions of cartilage proteoglycan binding region and link protein.

Binding region and link protein were prepared from pig laryngeal cartilage proteoglycans after chondroitinase ABC and trypsin digestion. Experiments on gel chromatography showed the purified binding region to interact reversibly with hyaluronate (HA), and this binding was also shown to be stabilized by native link protein. The trypsin-prepared link protein showed properties of self-association in solution that were partially inhibited by oligosaccharides (HA10-16) and abolished by modification of free amino groups (lysine residues) with 2-methylmaleic anhydride. The Mr (sedimentation equilibrium) of the modified link protein was 41 700. Analysis of binding region showed it to contain 25% (w/w) carbohydrate, mainly in galactose, glucosamine, mannose and galactosamine. It contained some keratan sulphate, as digestion with endo-beta-D-galactosidase (keratanase) removed 28% galactose and 25% glucosamine and the Mr (sedimentation equilibrium) decreased from 66 500 to 60 800. After keratanase digestion the interaction with polyclonal antibodies specific for binding region was unaffected, but the response in a radioimmunoassay with a monoclonal antibody to keratan sulphate was decreased by 47%. Preparation of a complex between binding region, link protein and HA approximately 34 showed a single component (5.5S) of Mr (sedimentation equilibrium) 133 500. In this complex the antigenic determinants of link protein appeared masked, as previously found with proteoglycan aggregates. The isolated binding region and link protein were thus shown to retain properties comparable with those involved in the structure and organization of proteoglycan aggregates.

Animals↗
PubMed2006

[Study on the relationship among the projective positions of interior laryngeal structure on thyroid ala].

OBJECTIVE: To provide anatomic basis of locations of laryngeal interior structures for laryngeal operating through lateral laryngeal approaches in clinic. METHOD: Thirty cadavers laryngeal cartilage specimens (19 male and 11 female) was collected. Using pin pierced method under direct vision to locate the projections of muscle process of arytenoids cartilage and vocal fold on thyroid ala, then to observe their relationships. RESULT: The projection of vocal fold is the line that connecting a little bit superior of the middle point of anterior commissure of thyroid cartilage and the point on the crosspoint of superior 3/4 and inferior 1/4 of the posterior edge of thyroid cartilage ala. The angle of the line and anterior commissure of thyroid cartilage is sixty-five degrees. The projection of muscle process is locating on the projective line of vocal fold. The projection of pyriform fossa is locating at the posterior superior portion of thyroid cartilage ala. CONCLUSION: The interior structures of larynx have a intact relationship of projective position on thyroid cartilage ala,which providing anatomic references for clinical surgeries relating to vocal fold through laryngeal framework.

Arytenoid Cartilage↗
PubMed1986

Cartilage proteoglycans.

The structure of the protein core of the high molecular weight aggregating proteoglycan from pig laryngeal cartilage has been investigated. Mild trypsin digestion of proteoglycan aggregates released a large (Mr approximately equal to 150K) protein-rich fragment that contained the hyaluronate-binding region (Mr 66K). Rotary-shadowing electron microscopy of this preparation showed it to contain 'double globe' structures, similar to those seen with intact proteoglycans. Interaction studies and immunochemical evidence showed that one of the globular domains was the binding region. The second globular domain did not interact with hyaluronate or share any major antigenic determinants with the binding region and its function remains unknown. Further evidence from rotary shadowing also suggested that the protein core contained a third globular domain at the C-terminal end. The complete protein core sequence thus contains long folded globular protein regions, in addition to the extended regions bearing glycosaminoglycan chains. Studies of proteoglycan turnover in explants of pig articular cartilage showed that proteoglycan fragments were continuously released into the medium during culture. These included large non-aggregating proteoglycan fragments, free binding region and also link protein. Proteoglycans retained within the cartilage matrix remained intact and able to aggregate. Only in the presence of interleukin 1 was there evidence of more extensive proteolytic digestion. The results suggest normal turnover to be a conservative mechanism involving the selective cleavage of proteoglycan close to the hyaluronate-binding region. This releases the major glycosaminoglycan-bearing domain and enables it to diffuse out of the matrix. The site of the initial cleavage appears to be in the region of the N-terminal globular domains.

Animals↗
PubMed1998

Vowel-related differences in laryngeal articulatory and phonatory function.

The purpose of this investigation was to study the interaction between the supralaryngeal and laryngeal components of the speech mechanism by examining vowel-related effects for a variety of vocal fold articulatory and phonatory measures. Secondary issues were to determine if vowel-related differences were influenced by the nature of the speaking task or gender. Between-vowel differences in estimated subglottal air pressure, peak oral air flow, mean phonatory air flow, air flow near the termination of the vowel, electroglottograph cycle width (EGGW), fundamental frequency, and voice onset time were examined for men and women during syllable repetitions and sentence productions. Significant vowel-related differences were found for all of the measures except mean phonatory air flow, and generally were not influenced by speaking task or gender. Vowel-related effects for estimated subglottal air pressure, peak oral air flow, fundamental frequency, and VOT were consistent with some earlier studies. New findings included vowel-related differences in EGGW and air flow near the termination of the vowel. We propose a model that includes the contribution of mechanical forces, reflexive neural activity, and learned neural activity to explain vowel-related effects. When vowel height is varied, changes in laryngeal cartilage positioning and vocal fold and vocal tract tension appear to influence laryngeal articulatory and phonatory function.

Adult↗
PubMedDate not supplied

Bilateral dystrophic ossification of the thyroid cartilage appearing as symmetrical laryngeal masses.

Primary cartilaginous lesions of the larynx are relatively uncommon. We present a case of bilaterally pseudocystic lesion of the thyroid cartilage that demonstrated progressive calcification. Pathologic analysis showed features suggesting a dystrophic lesion with no evidence of malignancy. We hypothesize that repetitive microtrauma related to muscular overuse probably led to inflammatory changes at tendinous insertions on the laryngeal cartilage and resulted in dystrophic ossification of the laryngeal cartilage.

Adult↗
PubMed2004

Recombinant human bone morphogenetic protein-2 enhances experimental laryngotracheal reconstruction in rabbits.

OBJECTIVE: Bone morphogenetic protein-2 offers potential benefits for cartilage regeneration. We investigated the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the regeneration of laryngeal cartilage and respiratory epithelium in a rabbit model. MATERIAL AND METHODS: We used a cricoid defect rabbit model. Twenty-four rabbits were randomly divided into four equal groups. Two groups were treated with 5 microg of rhBMP-2 delivered on an absorbable collagen sponge and the other two groups were used as controls. One group of treated rabbits and one group of control rabbits were euthanized 1 week after surgery, while the others were euthanized 4 weeks after surgery. The healing pattern of the laryngeal wound was evaluated by means of histomorphometry. RESULTS: Regeneration of both the epithelial layer and cartilage was significantly better in rabbits treated with rhBMP-2. Four weeks after surgery, the cricoid cartilage defect was completely repaired by new cartilage and new bone in rabbits treated with rhBMP-2. Furthermore, the lining respiratory epithelium healed more rapidly in treated rabbits. CONCLUSION: rhBMP-2, delivered via an absorbable collagen sponge, induces complete regeneration and repair of rabbit cricoid cartilage defects. It also induces faster relining and regeneration of airway epithelium than in control rabbits.

Animals↗