The frequency of sister chromatid exchanges increased in freshly isolated human lymphocytes as well as in a continuously growing lymphoblast line by exposure to diagnostic levels of ultrasound for 30 minutes. The results confirm previous findings indicating that ultrasound of diagnostic intensities can affect the DNA of animal cells.

Flow cytometric analysis of DNA content was performed on single or multiple samples from 34 thyroidectomy specimens. There were 29 thyroids with diploid DNA content, comprising 15 nonneoplastic lesions, 5 follicular adenomas, 1 medullary carcinoma, and 8 papillary carcinomas. Aneuploid DNA pattern was observed in five cases, including one metastatic mammary carcinoma. The initial histologic diagnoses in the remaining four aneuploid thyroid lesions were follicular carcinoma in one and follicular adenoma in three. The abnormal DNA pattern in the three follicular "adenomas" prompted a review of their aspiration cytologic and histologic features. The fine-needle aspiration biopsy was performed in two of the three cases and showed evidence of a follicular neoplasm with significant nuclear atypia in both. Histologic review of the three lesions led to a modified diagnosis of noninvasive low grade follicular carcinoma in all three. Flow cytometric analysis of DNA content may prove to be a highly useful adjunct in the evaluation of follicular thyroid tumors. Long-term clinical follow-up is warranted to document the clinical significance of these observations.

The effects of diagnostic levels of ultrasound on DNA of HeLa cells included: increased immunoreactivity to antinucleoside antibodies in G1 cells, strongly suggestive of unwinding of the helix or single-strand break induction, and low levels of non-semiconservative synthesis in logarithmically growing cells treated with hydroxyurea, indicating repair synthesis. In the C3H mouse cell line 10T-1/2, Cl 8, loss of contact inhibition with a criss-crossed growth pattern was seen. In one experiment, tumors developed in syngeneic mice at the site of injection of ultrasonically treated cells. Ultrasound in the diagnostic range appears to cause detectable effects on DNA and growth patterns of animal cells.

Fifty-eight effusions (42 pleural and 16 ascitic fluids) from patients with and without cancer were analyzed by conventional cytology and the results compared with DNA patterns generated by flow cytometry of 10(4) nuclei and several modes of Feulgen cytophotometry. In 31 patients (24 without evidence of cancer and seven with history of cancer and cytologically negative fluids), the fluids were diploid by flow cytometry. One fluid with atypical cells from a lymphoma suspect was also diploid. Flow cytometry of 26 cytologically cancerous fluids disclosed aneuploid DNA patterns in 16 and diploid patterns in ten. Feulgen cytophotometry of 11 of these fluids (three aneuploid, eight diploid) was performed on nuclear preparations identical to those used in flow cytometry and on restrained smears used for visual analysis. The analysis was performed in two modes: as a study of 500 sequential nuclei in an automated system, mimicking flow cytometry, and visually selected large, presumably malignant nuclei. In nine of the 11 cases, the DNA content of visually selected cancer cells was aneuploid, even though this DNA pattern was not evident in the analysis of 500 sequential cells. In two cases, both diploid by flow cytometry, the Feulgen analysis confirmed the presence of cancer cells in the diploid range. In samples of 10(4) nuclei representing a mixed population of cells occurring in effusions, the presence of aneuploid cancer cells may not be disclosed by conventional flow cytometry. A larger sample of cells, a detailed analysis of DNA histograms, and perhaps sorting of select cells in the hypertetraploid range, may prove essential before flow cytometry can be accepted as a diagnostic tool in the laboratory in the assessment of effusions.