Megumi Sawada

Determination of plasma tissue factor antigen and its clinical significance

SUMMARY. To investigate the clinical significance of determination of plasma tissue factor (TF) antigen, we have developed a highly sensitive enzyme‐linked immunosorbent assay (ELISA) for plasma TF, using two different monoclonal antibodies against TF apoprotein, 6B4 (catching antibody) and 5G9 (detecting antibody), and tetramethyl benzidine/H2O2 as substrates. Titration curves of recombinant human TF in buffer containing Triton X‐100 were linear within the range from 50 to 2000pg/ml. The total assay time was 3h. Ultracentrifugation and immunoblot analysis indicated that human plasma and urine contained 50 000g sedimentable and non‐sedimentable forms of TF, both of which were detected by our ELISA method.

Chromosome 9p deletion in squamous metaplasia in cystic lesion of the lung

A 70‐year‐old man presented with squamous cell carcinoma of the lung. Examination of the resected specimen showed a tumour and a thickly walled cyst not immediately adjacent to the main tumour. The surface of the cyst was lined by squamous metaplastic epithelium. Microsatellite analysis of microdissected specimens was performed with seven markers from four chromosomal regions. In the squamous cell carcinoma, a non‐informative homozygosity at two markers on 3p, loss of heterozygosity (LOH) at D5S346 on 5q, and LOH at D9S146, D9S150, and D9S1748 on 9p were detected. In the metaplastic epithelium of the cyst, LOH was detected at D9S1748 on 9p21. This appears to be the first report providing possible evidence of genetic changes by demonstrating allelic loss on 9p21 in the metaplastic epithelium of a cyst. This allelic loss might be related to an early step in carcinogenesis in lung cysts.