Tumor necrosis factor stimulates ornithine decarboxylase activity in human fibroblasts and tumor target cells

The activity of the polyamine biosynthetic enzyme, ornithine decarboxylase (ODC), has been shown to be rapidly modulated by a variety of growth regulatory molecules. In this report the effect of the growth modulatory peptide, tumor necrosis factor, on ODC activity was examined on two cell lines which express equivalent TNF binding properties, but differ in their growth response when exposed to this factor. TNF treatment of WI-38 fibroblasts stimulated both their growth and induced ODC activity 5-10-fold when measured 6-24 h after TNF incubation. TNF induced cytotoxicity in ME-180 cervical carcinoma cells and, interestingly, stimulated both ODC activity (3-6-fold) and putrescine accumulation when measured prior to the onset of cytotoxicity. Induction of ODC was TNF concentration-dependent and paralleled the concentration-dependency for cytotoxicity. Based upon studies with cycloheximide, de novo protein biosynthesis was required for TNF-mediated ODC induction in ME-180 cells. The effects of other growth inhibitory peptides and growth factors were analyzed for their combined effect on ODC activity in TNF-treated or untreated ME-180 cells. Interferon gamma treatment had no significant effect on basal ODC activity but inhibited TNF-mediated ODC induction by approximately 50%. EGF treatment resulted in a potent stimulation of ODC activity which was not affected by TNF pre-treatment or coadministration on ME-180 cells. These results suggest that TNF has properties which are similar to those of a growth factor and distinct from those of other growth inhibitory peptides. The early growth factor-like actions of TNF occur on both normal fibroblasts and some tumor cells and evidence suggests that these effects are antagonistic to the antiproliferative effects of TNF.     

The reaction of nitro-blue tetrazolium with d,l-L-tetrahydrofolate: The effect of pH,oxygen, formaldehyde and palladium(II)

d,l-L-Tetrahydrofolate (d,l-L-FH₄) transfers two electrons to nitro-blue tetrazolium (NBT) in oxygen-free buffers to form the highly coloured nitro-blue formazan and oxidized folate. Both the rate and extent of this reaction are affected by the pH, the nature of the buffer and the oxygen concentration. Inhibition of both the rate and extent of this reaction in air-saturated solutions by superoxide dismutase (SOD) indicates that the superoxide anion is an intermediate in the reaction so that formazan can be produced by both superoxide independent and superoxide dependent routes in air-saturated solutions.In oxygen-free solutions several lines of evidence can be interpreted to mean that the reduced pteridine ring of tetrahydrofolate is the electron donor in the reaction with NBT. Ionization of the amide hydrogen of the pteridine ring and subsequent increase in electron density of that ring might explain the large increases observed in the rate and extent of the reaction of tetrahydrofolate with NBT as the pH increases. Formaldehyde reacts non-enzymatically with tetrahydrofolate to form a methylene bridge between nitrogens 5 and 10 of methylenetetrahydrofolate. This molecule is much less reactive with nitro-blue tetrazolium than tetrahydrofolate. Complexes formed between tetrahydrofolate and palladium(II) ions are also less reactive with NBT than the tetrahydrofolate alone. This result provides added evidence that palladium(II) ions interact with tetrahydrofolate at the nitrogen 5, nitrogen 10 site of the molecule.     

The ratio of calcium carbonate/organic matrix in the valves of Mytilus galloprovincialis as an indication of marine pollution

The CaCO3/organic matrix ratio, in the valves of Mytilus galloprovincialis, decreases when increases the degree of marine biological pollution. Its periodic measurement in the shells of Mollusca grown in the same area is, therefore, very useful for the analytical control of the sea environment. The method here proposed is very simple as CaCO3 amount is measured by weighting the valves ashes at 600 degrees C while organic matrix amount is calculated by difference between the weight of dry sample and that of its ashes.     

New ribosomal RNA gene locations in Gossypium hirsutum mapped by meiotic FISH

In this study we have mapped newly identified rDNA loci in Gossypium hirsutum. Four new minor 18S-26S rDNA loci, in addition to the sites previously identified, were mapped using fluorescence in situ hybridization (FISH) to heterozygous translocation (NT) quadrivalents (IVs). The newly detected 18S-26S rDNA loci were mapped to the right arms of chromosomes 8, 9, 15, 17, 19, 20, and 23 and the left arms of chromosomes 5, 11, 12, and 14. Using the rDNA loci as common reference points, we detected several erroneous arm assignments in the previously published map of NT breakpoints. The data are summarized in the form of an integrated map for all 17 known rDNA loci, relative to centromeres, telomeres, and NT breakpoints. This information will facilitate future locus-specific research on rRNA gene evolution and function. Received: 26 January 1998; in revised form: 28 May 1998 / Accepted: 12 February 1999     

Chlorpromazine inhibits the calcium-mediated effects of S-100 protein(s) on assembled brain microtubule proteins, but not those on microtubule protein assembly

We have examined the S-100-chlorpromazine interplay at the level of brain microtubule proteins in vitro. The results indicate that in the presence of 0.12 M KCl and 10 microM free Ca2+ the inhibitory effect of S-100 on microtubule assembly is additive to that of chlorpromazine, but S-100 fails to potentiate the disassembling effect of 0.1 mM Ca2+ if added to assembled microtubule proteins after chlorpromazine and Ca2+, probably because of inhibition of S-100 by the phenothiazine. Chlorpromazine does not compete with S-100 for binding to purified tubulin.     

Angiotensin-converting-enzyme gene polymorphism and heart failure: a case-control study.

Heart failure (HF) is the final outcome of virtually all cardiovascular diseases and is a major and increasingly serious public health problem. The renin-angiotensin system plays an important role in the pathogenesis of cardiovascular disease. Insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) has attracted significant attention; it has been extensively investigated in a spectrum of cardiovascular phenotypes because of its correlation with serum ACE activity. There is controversy regarding the association of ACE I/D polymorphism with cardiovascular disease. The aim of this study was to investigate whether ACE genotype is associated with HF by comparing cases and controls. The study sample consisted of 229 cases with HF due to coronary heart disease or idiopathic dilated cardiomyopathy and 230 controls recruited from the general population. The ACE I/D genotype was identified using a polymerase chain reaction assay. No evidence was found to support an association between ACE genotype and HF.     

CTLA-4 blockade and the renaissance of cancer immunotherapy

Cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) plays a key role in restraining the adaptive immune response of T-cells towards a variety of antigens including tumor associated antigens (TAAs). The blockade of this immune checkpoint elicits an effective anticancer immune response in a range of preclinical models, suggesting that naturally occurring (or therapeutically induced) TAA specific lymphocytes need to be “unleashed” in order to properly fight against malignant cells. Therefore, investigators have tested this therapeutic hypothesis also in humans: the favorable results obtained with this strategy in patients with advanced cutaneous melanoma are revolutionizing the management of this highly aggressive disease and are fueling new enthusiasm on cancer immunotherapy in general.