Schwannoma of the trachea.

We recently encountered a tracheal schwannoma presenting as a polypoid mass. Computed tomography (CT) was very effective in evaluation of the size, shape and site of this rare tumour. Furthermore, CT images in the prone position made it easy to exclude tumour extension into the mediastinum.

The development of scholarship in the Igakkan. (1) The founding of the Igakkan.

The Igakkan was an institute for medical education in Tokugawa Japan, which was founded by Taki Motoaka (1693-1766) in 1765 and became a bakufu institution in 1791. This paper looks at the latter process (for the purpose of this abstract, I will refer to this as bureaucratization) in the context of Tokugawa educational policy, particularly in comparison with Shoheiko, a school for training bureaucrats. Also, this paper examines sources written during the Kansei period (1789-1801), many of which have been neglected in the field. I show that the Kansei reforms significantly shaped medical thought in the late Tokugawa period. The paper is divided into three parts, and will be published in this and the two forthcoming issues. The titles of the three parts are as follows: Part 1. The Founding of the Igakkan Part 2. Government doctors during the Kansei Reform Period, As Seen in Yoshino zoshi Part 3. The Place of Evidential Scholarship in the late Tokugawa Period. In Part 1, I show that while the Shoheiko confirmed Shushigaku (sometimes referred to as Neo-Confucianism) as an orthodoxy, supporting the existing political structure, the scholars in the Igakkan were never confined by Sushigaku.

The development of scholarhip in the Igakkan (2): government doctors during the Kansei reform period, as seen in Yoshino zoshi.

Yoshino zoshi has never been used in previous studies of Japanese medical history. It gives detailed information on government doctors during the time when the Igakkan was bureaucratized. It is a collection of reports of rumors written by his advisors for Matsudaira Sadanobu, the instigator of the Kansei reforms. Thus Yoshino zoshi was directly related to the formation of the reform policies. Furthermore, it reveals background stories behind official promotions and demotions, and the feelings of the individuals concerned, which are not visible in official documents. The following topics are discussed: rumors during the early Kansei Reform period; the clinical achievement reports as they related to promotions and demotions during 1788; the reputations of doctors in the service of daimyos and those serving townspeople; orders given to government doctors in 1789; the gambling scandal of Seijukan; the fall of the Nakarai family; the expanding power of Taki Rankei; the founding of the Igakkan; and the Ninomaru Seiyakujo.

Fractal analysis of interstitial lung abnormalities in chest radiography.

A computerized method for analyzing interstitial lung abnormalities seen on chest radiographs was investigated. The method includes two main steps: (a) extraction of linear opacities on chest radiographs and (b) calculation of the fractal dimension. Extraction of linear opacities uses the processes of four-directional Laplacian-Gaussian filtering, binarization, and linear opacity judgment. The fractal dimensions in the processed images are then calculated by using the box-counting algorithm. The accuracy of the computerized method in differentiating between normal and abnormal lung tissue was tested on digitized chest radiographs (0.175 mm pixel, 10-bit) of 100 randomly selected patients. One hundred regions of interest (ROIs) from radiographs of 50 patients with interstitial lung abnormalities and 100 ROIs from radiographs of 50 patients with normal lungs were analyzed. The fractal dimensions obtained from the ROIs in lungs with interstitial abnormalities were significantly higher compared with those from ROIs in normal lungs (mean, 1.67 +/- 0.10 vs 1.44 +/- 0.12, respectively; P < .001). This result indicates that fractal analysis is useful in distinguishing interstitial lung abnormalities from normal lung tissue on chest radiographs.