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Biomedical subjects

F C Adriaansen

Publications and source records attributed to F C Adriaansen.

11 recordsLinked to original sources

Growth dynamics of the cricoid cartilage and subglottic injury. An autoradiographic and histometric study in the rabbit.

Earlier studies in young growing rabbits have suggested that post-traumatic developmental deformities of the cricoid might play a role in failing treatment in children with similar injuries. Specific patterns of malformations in the animals occurred preferentially at the anterior side of the cricoid ring. In this study, the growth dynamics of the cricoid were studied by histometry and autoradiography. Results indicated that (1) the cell/matrix ratio remains unchanged from 4 to 24 weeks of age, with both tissue components thus contributing equally to growth of the cricoid; (2) mitoses occur in cartilage and perichondrium, indicating interstitial as well as appositional growth; (3) mitotic activity is mainly restricted to the first 4 weeks of life, while cell hypertrophy is thereafter the dominant feature; (4) the highest degree of mitotic activity and cell hypertrophy is found in the anterior half of the cricoid ring which therefore can be considered as a growth center. This center might play a role in the development of trauma-induced deformation in the anterior part of the cricoid ring.

Aging↗

Ectopic cartilage in subglottic stenosis: hamartoma or reaction to trauma?

In an experimental study in growing rabbits an endolaryngeal injury to the subglottis resulted in the development of a stenosis due to the formation of scar tissue containing ectopic cartilage. For comparison, biopsies taken from the subglottic stenosis in 8 children were studied histologically. In 6 cases ectopic cartilage was observed; all patients had a history of endotracheal intubation. In 3 children the diagnosis hamartoma was made. In the remaining 3 cases the formation of ectopic cartilage might have been a direct reaction to the endolaryngeal intubation. The observations suggest that the formation of ectopic cartilage in acquired subglottic stenosis is not always due to a developmental aberration such as a hamartoma.

Animals↗

The influence of ageing on wound healing of the cricoid.

In young and adult rabbits the effects of one anterior or two bilateral splits of the cricoid were studied. Interruption of the cricoid ring elicits wound healing of the cut edges and induces changes in form and size of the separated parts of the cricoid (indirect effect). It was demonstrated that with increasing age i) the wound healing capacities of the hyaline cartilage is highly diminished or lost and ii) the induced remodelling, involving the total ring in young animals, is in the adult stage confined to the posterior part. Moreover, the observations suggest that dividing the cricoid ring in an anterior and posterior part at a young age can result in a stimulation of growth of the anterior part, in comparison with unoperated control animals.

Aging↗

Differential effects of endolaryngeal trauma upon the growth of the subglottis.

In young rabbits (4-week-old) the growth of the subglottis was studied after an endolaryngeal soft tissue trauma. The injury induced the formation of a subglottic stenosis. In contrast to earlier observations on endolaryngeal trauma extending into the cricoid cartilage, the cricoid developed normally to the adult size and shape at 24 weeks. Similar to the earlier findings, the subepithelial layer showed considerable thickening as the result of formation of scar tissue, ectopic cartilage and fatty tissue with interruption of the elastic tunica (= conus elasticus). It was concluded that after endolaryngeal trauma in rabbits two types of subglottic stenosis can develop, determined by the depth of the injury.

Animals↗

Morphometric study of the growth of the subglottis after interruption of the circular structure of the cricoid.

In young rabbits the growth of the subglottis was studied over a period of 20 weeks after interruption of the circularity of the cricoid on the ventral side. In all cases the cricoid developed into a U-like structure which did not cause an airway narrowing. However, a cricoid lesion combined with an injury to the soft tissue lining led up to a subglottic stenosis. It was concluded that when the soft tissue layer is undamaged, an intact circular structure of the cricoid is not compulsory for the normal development of the subglottis.

Animals↗

Histologic study of the growth of the subglottis after interruption of the circular structure of the cricoid.

In a previous study in growing rabbits it was demonstrated that after resection of a ventral part of the cricoid the lumen of the subglottic airway developed normal size during further growth up to the adult stage. Histologic investigations of these cases suggest that a subepithelial network of elastic fibres, ventrally suspended to the thyroid and the tracheal rings, ensures the airway lumen and prevents the development of a subglottic stenosis. Resection of a ventral part of the cricoid including the adjacent soft tissue lining of the airway causes an irreversible loss of the supporting elastic layer and the formation of scar tissue resulting in a stenosis. It was concluded that the larynx and trachea can be considered as an inner, elastic tube (= conus elasticus) lined with epithelium, suspended to an outer, segmented cartilaginous tube. At the level of the subglottis an intact conus elasticus is of more importance for the normal development of the airway lumen in young rabbits than an intact ventral half of the cricoid ring.

Animals↗

A histologic study of the growth of the subglottis after endolaryngeal trauma.

In young rabbits the histologic features of the growth of the subglottis were studied after an endolaryngeal trauma. This lesion of the larynx leading to a subglottic stenosis, caused specific pathologic changes of the cricoid cartilage and the subepithelial tissues. Activation of chondrocytes resulted in proliferation and regeneration of destructed cartilage. The normal subepithelial structures were replaced by granulation tissue differentiating into a thick fibrous scar and into cartilage. This ectopic cartilage together with the repaired cricoid formed a composite thickened 'ring'-like cartilaginous structure in the adult stage.

Age Factors↗

A morphometric study of the growth of the subglottis after endolaryngeal trauma.

In young rabbits the growth of the subglottis was studied over a period of 20 weeks following an endolaryngeal trauma. This lesion of the larynx at the age of 4 weeks resulted in the development of a stenosis in the adult stage. The stenosis appeared to be caused by a specific change in the pattern of growth leading up to an anterior narrowing ('pear'-like) of the cricoid ring and a conspicuous thickening of the subepithelial layer.

Age Factors↗

Porous hydroxylapatite-perichondrium graft in cricoid reconstruction.

Composite grafts of hydroxylapatite-perichondrium were used for reconstructing defects in the cricoid of young rabbits. The alloplastic material showed no signs of resorption; it was firmly attached to the surrounding tissues by ingrowing connective tissue; only a moderate foreign body reaction was observed. The perichondrium formed new cartilage around the hydroxylapatite.

Animals↗