Ghost protein damage by peroxynitrite and its protection by melatonin.

We have studied the effect of peroxynitrite (ONOO-) on the membrane cytoskeleton of red blood cells and its protection by melatonin. Analysis of the protein fraction of the preparation by SDS-PAGE revealed a dose-dependent (0-600 microM ONOO-) disappearance at pH 7. 4 of the main proteins: spectrin, band 3, and actin, with the concomitant formation of high-molecular weight aggregates resistant to reduction by ss-mercaptoethanol (2%) at room temperature for 20 min.

Nitric oxide is released in regenerating liver after partial hepatectomy.

The induction of hepatic nitric oxide synthase (NOS) and the biosynthesis of nitric oxide (NO) were studied in liver after partial hepatectomy (PH). NOS activity in the liver remnant was observed 4 to 6 hours after PH, and no differences were evidenced between the proximal and distal surgical areas. The form of NOS expressed in liver was independent of calcium and calmodulin, and the messenger RNA levels were first detected 2 hours after hepatectomy using a probe corresponding to the cytokine-induced macrophage NOS.

Serum alkaline deoxyribonuclease activity, a sensitive marker for the therapeutic monitoring of cancer patients: methodological aspects.

Alkaline deoxyribonuclease (DNase) is present in human circulating serum but its physiological role and signification of its variations are still largely unknown. The present report demonstrates that between 37 degrees C and 50 degrees C, as measured in the presence of 0.25 mmol/l Ca2+ and 5 mmol/l Mg2+, serum alkaline DNase activity increases, in most sera, reaching a level far higher than expected from thermal activation.

[Possible value of variations in the serum alkaline DNAse activity in the prognosis of cancers of the upper respiratory-digestive tract treated by chemotherapy].

Variations in serum alkaline DNase activity before and repeatedly after standardized chemotherapy were examined in patients with head and neck carcinomas. The enzyme activity was measured by way of a modified spectrophotometric method. No variations of such activity observed in patients without therapeutic response or with minor response could be considered as a marker of primary or acquired resistance to chemotherapy.