MEDIASTINAL TUMORS OF THYMIC ORIGIN

Twenty-one cases of mediastinal tumors of thymic origin are presented. Five of these were benign and 16 malignant.Surgical excision is proposed as the treatment of choice for the encapsulated benign tumors or for malignant tumors of limited extent. When surgical excision is not feasible, adequate roentgen therapy amounting to 5,000 to 6,000 r calculated tumor dose may eradicate or control the tumor.No correlation between the histological pattern of the tumor and the survival rate or radiation response could be demonstrated in this small series.     

THE TREATMENT OF MEDIASTINAL TUMORS

Because there can be no certainty of diagnosis without it, thoracotomy is indicated in cases in which there is roentgenographic evidence of mediastinal tumor. “Watchful waiting” is considered unwise because the tumor may be malignant when first observed or may later undergo malignant change. Even if the lesion is and remains benign, an increase in the size of the mass may cause obstructive pressures necessitating operation ultimately. Moreover, infection and inflammation may develop at the site during prolonged observation, making operation more difficult.The hazards of thoracotomy, which have been greatly reduced in the last few years, are less than the hazards of waiting.     

SUBSTERNAL GOITER AND PULMONARY EMPHYSEMA

Pulmonary emphysema is not an infrequent complication of tracheal compression due to goiter.In many cases the goiter is in the mediastinum and therefore overlooked.Among 13 patients with this combination of disease, chronic cough, dyspnea and wheezing were the chief respiratory symptoms. Ten of the 13 patients also had hyperthyroidism; in eight of the ten the disease was of the “masked” variety and both the thyrotoxicosis and the mediastinal mass were overlooked.Early recognition and surgical removal of substernal goiter may prevent or retard otherwise irreversible and progressive tracheobronchopulmonary disease.Medical management of such cases with thiouracil preparations may lessen the toxic symptoms but probably will not affect the mechanical compression of the trachea.     

ANTERIOR MEDIASTINAL TERATOMAS IN INFANTS AND CHILDREN

This report reviews the management of five pediatric patients with anterior mediastinal teratomas, and presents a discussion of symptoms, signs, and operative management of these lesions. Surgical resection was accomplished in all cases, with three of the five patients surviving. The two who died had malignant teratomas that were treated with adjunctive chemotherapy and X-ray therapy. Age at onset appears to be a significant factor in the prognosis of the disease.     

蚱蝉的发声器结构:中纵隔膜

在雄蚱蝉(Cryptotympana atrata Fabricius)的体内,作者发现了白色略透明,并富有弹性的蝉体内最大的薄膜.厚约3.5μm,面积50.7mm²左右.该膜被称为中纵隔膜.中纵隔膜位于大气管气囊的矢状面,把大气囊分为相等的左右二气室,每个气室的容积约为700mm³.以中纵隔膜为界,雄蚱蝉有左右两个发声器,这两个发声器的结构相同,对称并相对独立.文中讨论了中纵隔膜在蝉鸣的发声和共振中的作用.蚱蝉自鸣声是在神经系统的控制下,由左右两个发声器协调工作发出的.在腹部共振中,中纵隔膜的振动为其中之一,比腹节的振动开始得早.