Interaction of topoisomerase I inhibitors with radiation in cis-diamminedichloroplatinum(II)-sensitive and -resistant cells in vitro and in the FSAIIC fibrosarcoma in vivo.

The cytotoxicity of the topoisomerase-I inhibitors, camptothecin and topotecan, toward the SCC-25 human head-and-neck squamous-carcinoma cells and the SCC-25/CDDP sub-line made resistant to cis-diamminedichloroplatinum(II) was assessed alone and in combination with radiation. Topotecan was less cytotoxic than camptothecin in cell culture and the SCC-25/CDDP cell line was more sensitive to either topoisomerase-I inhibitor than was the parental SCC-25 cell line. Both camptothecin and topotecan were effective radiation sensitizers of hypoxic SCC-25 and SCC-25/CDDP cells under normal pH or acidic pH conditions.

Persistent stapedial artery supplying a glomus tympanicum tumor.

Vascular anomalies of the middle ear are extremely rare. The most common anomaly is a persistent stapedial artery. This artery is important clinically because of the risk of profuse bleeding during middle ear surgery.

Evaluation of therapeutic potential of interleukin 2-expanded tumor-infiltrating lymphocytes in squamous cell carcinoma of the head and neck.

Tumor-infiltrating lymphocytes (TILs) were isolated from surgically excised squamous cell carcinoma of the head and neck. Immunohistology showed that the tumor was infiltrated by T-lymphocytes, many of which were activated as judged by the expression of the following surface antigens: HLA-DR, transferrin receptor, and receptors for interleukin 2 (IL2). Fresh TILs were unable to lyse natural killer cell (NK)-resistant and NK-sensitive tumor cell targets in chromium-release cytotoxicity assays.

Investigations of the mechanism of selective inhibition of type B mitochondrial monoamine oxidase by phosphatidylserine.

Liposomes of phosphatidylserine (PS) were found to inhibit strongly the B-form of membrane bound monoamine oxidase (MAO) isolated from rat and bovine liver, while having no effect on the rat liver A-form. Use of 14C-liposomes demonstrated high levels of PS association with the membrane, which could not be removed by extensive washing with high ionic strength buffers. The inhibition of MAO-B was not reversed on further perturbation of the membrane by chaotropic agents, sonication, or treatment with additional liposome preparations of phosphatidylcholine or phosphatidylinositol.