Assessment of usefulness of endobronchial ultrasonography in determination of depth of tracheobronchial tumor invasion.

STUDY OBJECTIVE: We assessed the usefulness of endobronchial ultrasonography in the determination of the depth of tumor invasion of the tracheobronchial wall. METHODS: We performed a needle-puncture experiment on normal tissue of 45 specimens to determine the laminar structure of the tracheobronchial wall. In addition, we compared the ultrasonographic determinations of tumor invasion from 24 lung cancer cases with the histopathologic findings. RESULTS: The cartilaginous portions of the extrapulmonary bronchi and the intrapulmonary bronchi exhibited a five-layer structure. Starting on the luminal side, the first layer (hyperechoic) was a marginal echo, the second layer (hypoechoic) was the submucosal tissue, the third layer (hyperechoic) was the marginal echo on the inner side of the bronchial cartilage, the fourth layer (hypoechoic) was bronchial cartilage, and the fifth layer (hyperechoic) was the marginal echo on the outer side of the cartilage. In the membranous portions, the first layer (hyperechoic) was a marginal echo, the second layer (hypoechoic) was smooth muscle, and the third layer (hyperechoic) corresponded to the adventitia. Comparisons between the ultrasonograms and the histopathologic findings in 24 lung cancer cases revealed that depth diagnosis was the same in 23 lesions (95.8%) and was different in 1 lesion (4.2%). In the single case in which the findings were different, lymphocytic infiltration that protruded between the cartilage rings was mistakenly interpreted as tumor infiltration. CONCLUSIONS: This method allows visualization of the laminar structure of the tracheobronchial wall, which is impossible with other diagnostic imaging methods.

[Anomalous origin of the left coronary artery from the pulmonary trunk with myocardial infarction and severe left ventricular dysfunction in infancy--assessment of myocardial damage using SPECT studies with 201TlCl and 123I-BMIPP].

A 4-month-old male infant with Bland-White-Garland (BWG) syndrome complicated myocardial infarction was reported. Signs included tachypnea, coughing, and failure to thrive. However, there was no sign of myocardial infarction. A chest radiograph revealed cardiomegaly (CTR = 65%) and electrocardiogram showed abnormal Q waves in I, aVL, V6 leads. Cardiac catheterization and angiography revealed marked dilatation of left ventricle (end-diastolic volume = 384 ml/m2) and extremely depressed ejection fraction (16%), confirming the diagnosis of BWG syndrome. A 201TlCl-myocardial SPECT demonstrated apical defect and hypoperfusion in the anterolateral, inferoposterior walls, whereas 123I-beta-methyl-p-iodophenylpentadecanoic-acid (123I-BMIPP) SPECT showed a wider defect area. SPECT studies with 201TlCl and 123I-BMIPP, are useful to assess myocardial viability more accurately in BWG syndrome.

Quantitative risk assessment of carcinogenicity of urethane (ethyl carbamate) on the basis of long-term oral administration to B6C3F1 mice.

A carcinogenicity study of urethane was performed for quantitative assessment of its risk in humans. Three hundred 6-week-old male B6C3F1 mice were divided into 6 groups, each consisting of 50 mice, and urethane was given ad libitum in drinking water at levels of 0 (control), 0.6, 3, 6, 60 and 600 ppm for 70 weeks. The tumors with a clear dose-response relationship were lung tumor (alveolar/bronchiolar adenoma or carcinoma) and liver tumor (hemangioma or angiosarcoma). The incidences of these two types of tumor were applied to estimation of the virtually safe dose (VSD) at the level of 10(-6) by using four mathematical models (Logit, Probit, Weibull and Multistage models). The VSD based on the incidences of lung tumor by using the Logit model was estimated to be 1.8 x 10(-4) mg/kg body weight/day. On the other hand the VSD based on those of liver tumor by using the Weibull model was 7.2 x 10(-5) mg/kg body weight/day. Thus, the VSDs based on the incidences of the two different types of tumor using the most compatible mathematical model in each case, as judged from the P-values, were similar.