Ambiguus motoneurons innervating laryngeal and esophageal muscles are malpositioned in the Reelin-deficient mutant rat, Shaking Rat Kawasaki.

CONCLUSIONS: The present study confirmed that ambiguus motoneurons innervating intrinsic laryngeal and esophageal muscles are radially malpositioned in the brainstem of the Shaking Rat Kawasaki (SRK), a reelin-deficient mutant rat. OBJECTIVES: Ambiguus motoneurons innervating the striated muscles of the larynx and esophagus take a long migration from their original birth plate in the floor of the fourth ventricle to their final settlement in the ventral margin of the medulla oblongata. To examine whether the migration of ambiguus nucleus neurons is affected in SRK, we studied localization of ambiguus motoneurons of postnatal day 21 (P21) normal and SRK rats. MATERIALS AND METHODS: To label ambiguus motoneurons retrogradely, horseradish peroxidase (HRP) was injected into some laryngeal muscles including cricothyroid, thyroarytenoid and posterior cricoarytenoid muscles, and the cervical and abdominal esophageal muscles of the SRK and normal controls 2 days before sacrifice. RESULTS: In the P21 normal rat, HRP-positive laryngeal and esophageal motoneurons were found in the nucleus ambiguus, whereas in the P21 SRK, they were scattered from the base of the fourth ventricle to the ventro-lateral margin of the medulla, suggesting that radial migration of ambiguus motoneurons from their birthplace to their final settlement is guided by Reelin protein.

A newborn case of congenital laryngeal cyst complicated with pneumothorax and pneumomediastinum.

Benign congenital laryngeal cysts are rare entities. They often cause chronic hoarseness and severe stridor. Case reports of congenital laryngeal cyst complicated with pneumothorax and pneumomediastinum are very rare. A 3,112 g full-term male newborn developed stridor which got worse during crying for 12 h after birth. Chest retractions were present with inspiration. Chest X-rays showed the presence of right pneumothorax and pneumomediastinum. Transnasal flexible laryngoscopic examination revealed a large cystic mass, which occupied almost the entire supraglottic airway. The operation was performed with the techniques of laryngomicrosurgery under general anesthesia. The cystic wall was punctured and serous liquid contents were aspirated. Excision of the entire cystic lesion was performed. The next day, extubation was performed without any troubles. The stridor had disappeared and the pneumothorax and pneumomediastinum were improved without further medical intervention. The histopathological examination revealed that the cystic wall consisted of normal squamous epithelial cells. It is reasonable to think that the high airway pressure due to congenital laryngeal cyst was responsible for pneumothorax and pneumomediastinum.