No abstract

To elucidate the influence of radiation therapy on the larynx in patients who receive radiotherapy to the neck, we observed the changes in the distribution of the laryngeal glands. Human adult larynges from patients with either laryngeal or hypopharyngeal cancer were histopathologically examined, and the changes in the glandular distribution as well as in the ratio of serous or mucous type cells were surveyed using an image analysis system. The mean ratio of the area occupied by glandular acini in the subglottic larynx was 0.182 in the non-radiation group and 0.098 in the radiation group (p < 0.001). Although no statistical difference was observed, the average density of the glands decreased and the average ratio of serous-type/mucous-type glandular cells decreased in the irradiated larynx. The glandular acini are often replaced with fibrous connective tissue and the ratio of serous-type glandular cells decreases. These results indicate that not only the voice function but also the local defence function of the larynx might be impaired after radiotherapy.

This study examined the local immune status and tumour marker expression in secretions and related tissue specimens from the laryngeal ventricle, comparing individuals with and without head and neck cancer. Laryngeal secretion and mucosal tissue specimens were collected during laryngeal microsurgery or surgical laryngectomy. The laryngeal secretions were found to contain immunological factors such as immunoglobulins G and A and secretory immunoglobulin A. A high level of the tumour marker Cyfra 21-1 was also detected in laryngeal secretions and mucosal tissue. Lows levels of secretory immunoglobulin A and Cyfra 21-1 were seen in the laryngeal mucosal tissue of controls and patients who had previously undergone radiation therapy. The level of secretory immunoglobulin A in laryngeal secretions closely correlated to the level of this immunoglobulin in mucosal tissue. These results indicate that local immunity is present in the human larynx; furthermore, it is strongly affected both by the presence of malignancy and by laryngeal cancer treatments such as irradiation.

No abstract

Electromyographic investigations of the intrinsic laryngeal muscles were carried out in 29 human cases with recurrent laryngeal nerve paralysis and in 14 canine cases, in which unilateral recurrent laryngeal nerve paralysis was experimentally caused by various methods of crushing, section and suture after section of the nerve. The observations in dogs were repeated before the operation and several minutes, several days, a i onth and every months up to death after causing paralysis. The laryngoscopic view of the position of the vocal cords was compared with the electromyogram in every case.