Morphology of laryngeal cartilage of the nine-banded armadillo (Dasypus novemcinctus) Linnaeus, 1758.

Armadillos, Xenarthras representatives, known for adaptability to different ecosystems, own specific morphophysiological characteristics that are not known and deserve to be studied. The aim of this study was to describe the morphology of cartilage of the larynx of the nine-banded armadillo (Dasypus novemcinctus). Five dead armadillos were donated by the Chico Mendes Institute of Biodiversity (ICMBio-PI) to the Federal University of Piauí. The animals were fixed and dissected for removal of the larynx. The cartilages were identified and described, photodocumented, and schematized. Fragments with about 0.5 cm of each cartilage were collected and submitted to classical histology for Hematoxylin-Eosin coloring. The slides were assembled in enterlan and analyzed under a light microscope. The larynx of the armadillo (D. novemcinctus) is located in the mentonian region, ventral to the esophagus, and due to the total positioning of the tongue in the oral cavity, there is also a cranial cervical position in this species. The larynx has five cartilages, they are: a cricoid, a thyroid, an epiglottis, and two arytenoids. The corniculate process is present; however, the cuneiform process is absent. The epiglottis has a discrete bifurcation at its apex. In all cartilages epithelial variations are observed. The tissues are varied from squamoso stratified to cylindrical pseudostratified, with propria lamina rich in mucoserosas glands. With the exception of epiglottic cartilage, predominantly elastic, the rest are hyaline. The larynx of D. novemcinctus, although the same number of cartilages, differs morphologically and microscopically from the larynx of other species.

Observations on the structure and the biomechanics of the cricothyroid articulation.

We examined quantitatively the ventrodorsal gliding occurring along a sagittal plane in the cricothyroid articulation. For this purpose we used 10 fresh excised human larynges taken at autopsy. Furthermore we examined the morphology, the hydroxyproline content and collagen types of the ligaments and the articular capsule of the cricothyroid articulation. This articulation appeared to be a synovial joint, supported by two ligaments: the lateral and posterior ceratocricoid ligament and articular capsule. The ligaments and the capsule contained both type I and type III collagen fibres and they were rich in elastin fibres 1-2.5 microns in diameter. Ventrodorsal gliding was generally possible when the joint was not rotated to its extremes. The marked individual variation was not essentially affected by sex or age. The collagen content of the lateral ceratocricoid ligament showed a statistically significant negative correlation with the gliding. The articular facet of the cricoid cartilage, which was not usually well-shaped, limits the gliding. A force of +/- 1.0 N caused on the average a change of +/- 1.0 mm in the length of the vocal cord. Further research is needed to evaluate the physiological importance of these findings.

Laryngotracheal stenosis in spondyloepiphyseal dysplasia.

Laryngotracheal stenosis has not been reported previously as a manifestation of spondyloepiphyseal dysplasia. Two recent cases are reported detailing the upper airway pathology encountered. The clinical features of spondyloepiphyseal dysplasia are reviewed in an attempt to develop a treatment protocol for such patients with laryngotracheal stenosis. The ultrastructural abnormalities found in these patients' cartilages are emphasized. Caution is advised before attempting laryngotracheoplasty.

[The determination of the earliest signs of cell damage after translaryngeal intratracheal long-term intubation in rabbits. A light- and electron-microscopic study]. / Licht- und elektronenmikroskopische Untersuchungen zur Ermittlung des frühesten Schädigungszeitpunktes nach translaryngealer intratrachealer Langzeitintubation beim Kaninchen.

Eighteen New Zealand rabbits were artificially respired, orotracheally with a cuff pressure of approximately 35 mm Hg, for between 2 and 36 h. After 2 h artificial respiration cell degeneration was seen in the area of the cuff, above the cartilage rings, in the form of cytoplasmic degeneration. After a 4 h intubation period an epithelial loss was seen. The basal membrane was intact. A connective tissue oedema, which was limited to the region of the epithelial lesion, became more wide-spread over the 36 h of intubation. A well-developed ulcer could be identified under the light microscope after 36 h. Increased mucous production as well as an increase in bacteria could be observed after 4 h. At no time could a degeneration of the cartilage be seen in the electron micrographs. The intercartilaginous area also remained free from cell degeneration although signs of vascular congestion could be seen.

Immediate mucosal effects of short-term, soft-cuff, endotracheal intubation. A light and scanning electron microscopic study.

Little is known regarding the early pathogenesis of intubation-induced laryngotracheal damage or the effects of presently used soft-cuff endotracheal tubes. We have examined the pathological changes of short-term intubation (four hours) in six mongrel dogs. Interaction of the endotracheal tube with the mucosa produced a variety of lesions ranging from superficial abrasions to ulcerations with the most severe lesions in the respiratory epithelium. Changes are present at the free surfaces of ciliated cells that include flattening, fusion, and erosion of cilia of sufficient extent to compromise ciliary function. The ischemic and mechanical modes of injury are compared; the latter is considered causal with modern soft-cuff tubes. These studies reveal tube-induced mucosal damage of an extent and nature not previously appreciated.

Ultrastructure of human foetal and neonatal hyaline cartilage.

Ultrastructural studies showed that human foetal and neonatal hyaline cartilage contained at least two types of chondrocytes. The predominant chondrocytes of chief cells were characterised by scanty, flat endoplasmic reticulum, few mitochondria, a rudimentary Golgi zone, and by the presence of clear cytoplasmic vacuoles which contained electron-dense granules and beaded filaments. The second type of cells had dark or electron-dense cytoplasm which contained numerous dilated endoplasmic reticulum and prominent Golgi zones; these cells gave rise to slender cytoplasmic processes from which the matrix vesicles were probably derived. The lacunar matrices surrounding both cell types were morphologically different reflecting some functional differences between these cells. Both types of cells participated in the formation of costochondral growth zones. Condrocytes with morphology of the chief cells proliferated, columnised, underwent hypertrophy, and differentiated either into a compact hypertrophic cell or a swollen pale cell. The cells also became hypertrophic and gave rise to increasing numbers of dense vesicles. Calcification was first noted in the longitudinal septa inside or adjacent to matrix vesicles. The recognition of the heterogeneity of chondrocytes in human hyaline cartilage may be helpful in understanding the pathology of the chondrodysplasias.

Structure of the normal rat larynx.

Recent studies have shown the rat larynx to be an important organ in the evaluation of irritancy of inhaled materials. Serial sections and scanning electron microscope observations have clarified its basic structure. In particular the cartilage pattern and the distribution of the epithelia lining the lumen have been determined. There are 2 specialised epithelia--stratified squamous (found in areas subject to wear) and ciliated pseudostratified columnar (which produces and transports mucus). Aways intervening between these is an unspecialised epithelium, the non-ciliated columnar. The marked variation in type of epithelium over a short distance within the larynx emphasises the need to take sections in the same plane when comparing different specimens.