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ACC3, a human adenoid cystic carcinoma cell system of salivary gland origin, is able to synthesize and secrete a large amount of basement membrane molecules in vitro. To define the ultrastructural secreting pathway of these molecules, we immunolocalized heparan sulphate proteoglycan (HSPG) in ACC3 for 7 days of culture. In the early stage of culture, the main compartments immunolabelled were rough endoplasmic reticulum (rER) and small secretory vesicles. From days 3 to 4 after plating, it was noticed that HSPG was localized in partially dilated spaces of the perinuclear, rER and Golgi cisternae and in lysosomes or those fused with multivesicular bodies and endosomes. On and after day 5, almost every Golgi apparatus showed marked dilatation of the cisternae and HSPG was immunolocalized in these dilated spaces. In the later stage of culture, autophagic vacuoles or secondary lysosomes, which were simultaneously labelled for HSPG and cathepsin D, were accumulated in the cytoplasm. HSPG deposition in the intercellular space was clearly demonstrated from day 1 and increased during the culture. The results indicate that ACC3 cells have an enhanced turnover cycle for HSPG: not only its biosynthesis but also degradation of both endogenous or exogenous HSPG. Such intracellular events may be reflected in the characteristic histology and biological behaviour of adenoid cystic carcinomas.

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In order to assess the usefulness of repeated sonography in detecting cervical lymph node metastases at the earliest stage during a follow-up period in patients with stage I / II carcinoma, 20 consecutive patients with stage I / II squamous cell carcinoma of the tongue were studied. Each patient was examined repeatedly with sonography during the follow-up period. Nine metastatic nodes in 9 of the 20 patients (45%) met our criteria, and were detected by repeated sonography.Histopathological examination revealed that 14 nodes had metastatic foci. Although the sensitivity, per node, of sonography was originally only 64%, follow-up sonography detected all of the subclinical subsequent lymph node metastases among the patients in this study. In conclusion, repeated sonography was useful in the detection of lymph node metastases during follow-up care of patients with stage I t II tongue carcinoma, provided that the follow-up examination was performed at maximum interval of one month, if possible, sonography should be performed in such cases at two-week intervals for at least one and a half year.

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