Comparison of 5-bromo-2-deoxyuridine and [3H]thymidine for studies of hepatocellular proliferation in rodents.

Hepatocyte replication traditionally has been studied by [3H]thymidine (TdR) incorporation into DNA, and more recently using incorporation of 5-bromo-2-deoxyuridine (BUdR), a synthetic analog of thymidine which is measured by immunohistochemistry. In studies to compare TdR and BUdR, mice were given the peroxisome proliferator [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (WY-14643) in the diet (0.1%) for 5 days and either TdR (1 microCi/g) or BUdR (100 mg/kg) on days 2-5. The labeling index (LI) for hepatocytes of WY-14643-treated mice was 4.7% with BUdR and 5.2% with TdR. The LI for control mice was 0.3-0.4% with either label. Partially hepatectomized rats given TdR had a mean LI of 30.0 versus 32.0% in rats labeled with BUdR. Sham-operated controls given TdR had a mean LI of 0.2% and BUdR controls had a mean LI of 0.1%. Hepatectomized rats given TdR and BUdR simultaneously had an LI of 20.1% for TdR and 22.4% for BUdR. In these rats, 94.1% of the labeled cells contained both markers, whereas 1.9% had only TdR and 4.0% had only BUdR. Comparable labeling indices using either TdR or BUdR indicate that the analogs may be used interchangeably in short-term in vivo studies of liver cell proliferation.

Monoclonal antibody L/1C2 reactive with a human carcinoma associated antigen.

A murine IgG3 monoclonal antibody which defines a human carcinoma associated antigen is described. The antibody, designated L/1C2, was made against a human lung squamous cell carcinoma line designated USCLS-1. It reacts with the surface of 15 of 16 viable human carcinoma cell lines and was detected in 70 of 78 frozen sections of human carcinomas. Melanoma cell lines and frozen sections of melanomas and a lymphoma were unreactive. Normal tissue reactivity included vessels, plus some ducts, glandular structures, and epithelial surfaces. Similar normal tissue reactivity patterns were seen with Rhesus monkey tissue samples. Immunoprecipitation studies indicate that L/1C2 reacts with a glycoprotein doublet which migrates in the range of 110,000 to 140,000 Mr under reducing conditions. Fluorescence analysis suggests this antigen is internalized following reaction with the L/1C2 antibody. Using in vitro human tumor cell growth inhibition assays, it was possible to achieve significant growth inhibition with L/1C2, while another target cell-reactive antibody in the same assay had no inhibitory effect.

Parathyroid cytopathology.

Cytologic criteria for diagnosing parathyroid adenomas and hyperplasia have not been elucidated. This report will present the cytomorphology of parathyroid tissue in the spectrum of normal, hyperplastic, and neoplastic states. We examined clinical needle aspirates from three patients with parathyroid lesions as well as 15 needle aspirations or touch preparations from surgical specimens. The series included three with hyperparathyroidism secondary to chronic renal failure, four with primary chief cell hyperplasia, nine with typical adenomas, and two with atypical adenomas. Normal parathyroid glands were also studied. Most parathyroid lesions could be distinguished from thyroid lesions by frequent thick fragments of cohesive cells with frayed edges and typical nuclear features. In general, the nuclei were small (6-8 mu) and round with regular coarse granular chromatin. Occasional larger nuclei (10-30 mu) with similar chromatin were observed in some cases. Oxyphil cells with abundant granular cytoplasm were present in some cases; one case with mostly oxyphil cells was difficult to differentiate from a thyroid neoplasm. Pseudocolloid was found in seven cases. Criteria for the differentiation between parathyroid hyperplasia and adenomas were not discovered. In addition, the cytology and differential diagnosis of atypical parathyroid adenomas are described and illustrated.

Intranuclear cytoplasmic inclusions in aspirates of follicular neoplasms of the thyroid. A report of two cases.

Two cases are reviewed in which the presence of intranuclear cytoplasmic inclusions in fine needle aspiration biopsy specimens of the thyroid suggested a diagnosis of papillary carcinoma. Subsequent surgical specimens were consistent with diagnoses of microfollicular adenoma and follicular carcinoma. These cases suggest that the presence of intranuclear inclusions in epithelial thyroid cells is not limited to papillary and medullary carcinoma, as some authors have suggested.