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Biomedical subjects

L L Doane

Publications and source records attributed to L L Doane.

3 recordsLinked to original sources

Effective chemotherapy for melanoma after treatment with interleukin-2.

Twenty patients with biopsy-proven metastatic malignant melanoma, previously treated with interleukin-2 (IL-2), received combination chemotherapy for progressive disease. Treatment included carmustine, cisplatin, dacarbazine, and tamoxifen (BCDT). Nausea was the most common toxicity (100%) and usually was mild. Persistent thrombocytopenia was the most frequent toxicity limiting further treatment. Eleven patients (55%) had an objective partial response, three patients (15%) had a minor response, and six patients (30%) had no change or progressive disease in response to this treatment. These results were comparable to the high response rates (21 of 40, 53%) achieved with BCDT in previously untreated patients with melanoma. It was concluded that prior therapy using IL-2 does not significantly alter the response rate of metastatic melanoma to BCDT, thus suggesting that immunomodulators (e.g., IL-2) and chemotherapeutic agents are not cross-resistant treatments.

Adult↗

Hairy cell leukemia. Current management.

The long-term outlook for patients with HCL has brightened over the last 5 years with the development of two highly effective systemic therapies, pentostatin and alpha-interferon. Pentostatin can induce complete responses in over 75 per cent of patients and may offer cure in this disease. Splenectomy continues to have a role as first-line therapy in selected patients in whom it may offer a median remission duration of over 5 years. Alpha-interferon is the treatment of choice for patients requiring initial systemic therapy and can be used intermittently to re-induce remission in patients with disease progression off therapy. Outside of clinical trials pentostatin should be utilized only in appropriately selected patients refractory to interferon therapy.

Bone Marrow↗

DNA-stimulated ATPase activity on the lon (CapR) protein.

The gene product of the pleiotropic lon (also called capR) locus in Escherichia coli, the CapR protein, is an ATP hydrolysis-dependent protease and a nonspecific nucleic acid-binding protein. We demonstrated that it is also a DNA-stimulated adenosine triphosphatase (ATPase). This new activity is distinct from the protease-associated ATPase activity and occurs in the absence of proteolytic substrate. The reaction requires the presence of a divalent cation and has a pH optimum of 8.0. The products of the reaction are ADP and inorganic phosphate. No adenylation or phosphorylation of the DNA or proteins was detected. The maximum rate of ATP hydrolysis occurs in the presence of supercoiled (form I) DNA. Relaxed circles (form II), double-stranded DNA, and single-stranded DNA are less effective in promoting ATPase activity, whereas RNA is inactive. The DNA-stimulated ATPase activity is inhibited by a mutationally altered form of the CapR protein called the CapR9 protein. The interaction of the CapR and CapR9 subunits suggests that this enzymatic activity of the CapR protein is oligomeric in the presence of DNA. Our in vitro experiments indicate a possible role for nucleic acids in the regulation of all lon (capR) activity.

ATP-Dependent Proteases↗