Influence of 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) on cell cycle progression and proliferation of cultured arterial smooth muscle cells.

8-(N,N-Diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), a putative inhibitor of intracellular calcium mobilization, causes a dose-dependent inhibition of serum-induced proliferation of arterial smooth muscle cells in culture. Neither early rise in cytosolic calcium concentration nor induction of early induced cell cycle dependent genes (c-fos, ornithine decarboxylase) are inhibited after serum stimulation in presence of 100 microM TMB-8. In contrast, expression of thymidine kinase, a gene normally induced in late-G1 phase, is entirely inhibited by TMB-8.

Deoxyribosyl exchange reactions leading to the in vivo generation and regeneration of the antiviral agents (E)-5-(2-bromovinyl)-2'-deoxyuridine, 5-ethyl-2'-deoxyuridine and 5-(2-chloroethyl)-2'-deoxyuridine.

In the rat, the highly potent anti-herpes drug (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdUrd) is rapidly converted to its base (E)-5-(2-bromovinyl)uracil (BVUra) through the action of pyrimidine nucleoside phosphorylases. However, BVdUrd can be regenerated or even generated de novo from BVUra by a pentosyl transfer reaction upon the administration of 2'-deoxythymidine (dThd), 2'-deoxyuridine (dUrd) or 5-ethyl-2'-deoxyuridine (EtdUrd). The antiherpetic drugs EtdUrd and 5-(2-chloroethyl)-2'-deoxyuridine (ClEtdUrd) can also be regenerated or generated de novo from their respective bases 5-ethyluracil (EtUra) and 5-(2-chloroethyl)uracil (ClEtUra), by a pentosyl transfer mediated by the administration of dThd or dUrd as deoxyribosyl donor.

Effect of (E)-5-(2-bromovinyl)uracil on the catabolism and antitumor activity of 5-fluorouracil in rats and leukemic mice.

In contrast to thymine and 5-fluorouracil (FUra) which were cleared from the bloodstream within 2-4 h after their i.p. administration (200 mumol/kg) to rat, (E)-5-(2-bromovinyl)uracil (BVUra) maintained a concentration of 50-70 microM for at least 6 h and was still present in the plasma 24 h after its administration.

Regeneration of the antiviral drug (E)-5-(2-bromovinyl)-2'-deoxyuridine in vivo.

The highly potent and selective antiherpes drug BVdUrd [(E)-5-(2-bromovinyl)-2'-deoxyuridine] is cleared within 2-3 hours from the bloodstream upon intraperitoneal administration to rats. It is degraded to BVUra [(E)-5-(2-bromovinyl)uracil] and this inactive metabolite is cleared very slowly from the bloodstream so that 24 hours after the administration of BVdUrd, BVUra is still detectable in the plasma. This contrasts with several other 5-substituted uracils, i.

Phosphorolysis of (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) and other 5-substituted-2'-deoxyuridines by purified human thymidine phosphorylase and intact blood platelets.

Various 5-substituted-2'-deoxyuridines (dUrd), including 5-ethyl,5-propyl-, 5-trifluoromethyl-, 5-hydroxymethyl-, 5-formyl-, 5-vinyl-, (E)-5-(2-chlorovinyl)-, (E)-5-(2-bromovinyl)-, 5-fluoro-, 5-chloro-, 5-bromo-, 5-iodo-, 5-cyano-, 5-thiocyano-, 5-nitro- and 5-amino-dUrd, were shown to be effective substrates for the thymidine (dThd) phosphorylase isolated from human blood platelets. Some of dUrd analogs, i.e.

Formation of monohydroxyeicosatetraenoic acids from arachidonic acid by cultured rabbit aortic smooth muscle cells.

In addition to the well established cyclooxygenase pathway, cultured aortic smooth muscle cells convert arachidonic acid to several polar metabolites identified by high performance liquid chromatography and gaz chromatography-mass spectrometry. 15-Hydroxyeicosatetraenoic acid, 12-Hydroxyeicosatetraenoic acid and 5-Hydroxyeicosatetraenoic acid are the major products formed. These observations indicate that the rabbit aortic smooth muscle cells are a potential source of lipoxygenase products and raise the possibility that this pathway of arachidonic acid metabolism can influence the biological functions of arterial myocytes under normal and pathological conditions.

Influence of cell density on collagen biosynthesis in fibroblast cultures.

Characteristic features of collagen metabolism in human skin fibroblasts were studied in relation to cell density. Measuring peptide-bound hydroxyproline we found that collagen synthesis per cell decreased when cultures approached confluency. On the other hand, the relative rate of collagen synthesis (collagen/total protein) was higher in quiescent than in proliferating cultures.

The human blood platelet: a cellular model to study the degradation of thymidine and its inhibition.

Intact platelets catabolize extracellular thymidine into thymine. Studies of the concentration dependent degradation of thymidine by intact platelets indicate a Michaelis mechanism with an apparent Km of about 0.12 mM and a Vmax of 2.

Catabolism of thymidine in human blood platelets: purification and properties of thymidine phosphorylase.

A pyrimidine nucleoside phosphorylase was partially purified from human blood platelets. The purified enzyme, as well as crude enzyme preparations, catalyses the phosphorolysis of thymidine and deoxyuridine, but not of uridine, and is able to catalyse direct pentosyl transfer from these deoxyribonucleosides to uracil or thymine; this enzyme has the properties of a thymidine phosphorylase. It has a molecular weight of about 110,000 and is composed of two identical subunits; it is phosphate dependent, has a maximal activity at a pH value of 5.

[Partial purification and characterization of thymidine phosphorylase in human platelets].

An enzyme which catalyzes the phosphorolytic cleavage of thymidine, and whose behaviour is characteristic of thymidine phosphorylase, was purified 130 times from human blood platelets. The results obtained by chromatography and electrophoresis, enable us to consider the existence of a dimeric form of this enzyme.

[Biosynthesis in vitro of extracellular matrix in arteriosclerotic areas of rabbit aortas. Autoradiographic study of tritiated proline incorporation kinetics].

The elaboration of the extracellular matrix was investigated by radio-autoradiography after incubation of aortic strips, isolated from thoracic aortas of healthy and atherosclerotic rabbits, with tritium labeled proline. Time course experiments indicated that there was a delay of about one hour before significant amounts (25%) of tritiated macromolecules were released from the intact smooth muscle cells. On the contrary, both, the level of incorporation and the rate of excretion of macromolecular components by modified smooth muscle cells of the atherosclerotic area from injured strips were increased.

[Study of the extracellular macromolecular meshwork elaborated by rat aortic cells in secondary culture].

Rat aortic smooth muscle cells isolated by digestion of the vessels by elastase and trypsin and grown in subculture, are examinated by phase, optic and electron microscopy for their ability to synthesize connective tissue components. Large amounts of extracellular material accumulates within the spaces between the cell; it consists of amorphous substance identified histochemically as elastin, of 110 A microfibrils and of periodic fibrils (430-490 A); the chemical nature of these two last components is discussed.

[Influence of a lathyric agent and of hypercholesterolemic serum on cell cultures of fetal rabbit aorta].

Cell cultures of foetal rabbit aorta are cultivated with a lathyric agent (beta-amino-propio-nitrile) or with an hypercholesterolemic serum; if morphological features, in these two cases, correspond with modifications observed, in vivo, when adult rabbits are respectively submitted to the same treatment, enzymatic activities of collagen metabolism vary in opposite way. Therefore, the influence of different parameters to be studied on vascular cell functions become easier.

[Enzyme alterations of the arterial wall following the combination of a lathyrogenic treatment and of moderate hypercholesterolemia in the young rabbit].

To determinate the part of humoural and parietal factors in atherosclerotic injury genesis, metabolism alteration study is realised on aortic cell wall of rabbits which are submitted to a chronical lathyritic intoxication alone, or simultaneously or alternatively associated with a cholesterolemic diet. Catabolic activity increase of beta-glucuronidase occurs in hypercholesterolemic rabbits. Beta-aminoproprionitrile, lathyrogenic drug used, stimulates biosynthetic pathways: increase of soluble proteins, energetic enzyme activities (lacticodeshydrogenase, malicodeshydrogenase), conjonctival protein metabolism (procollagen lysyl hydroxylase); in the same time, cell wall disturbances and lipidic deposits are facilitate when rabbits are submitted to cholesterolemic diet.