Biomedical research in developing countries. I--The Algerian case (1993-1998).

Biomedical articles emerging from Algeria between 1993 an 1998 were analysed in order to evaluate the scientific output. By developing a search strategy based on complementary bibliographic databases, 221 articles were retrieved, which geographic location, research topic, language, journal name and impact factor were analysed. International collaborations resulted in a profound change of the publication profile in terms of language, journal impact factor, and above all a change in research interests.

De novo synthesis of arginine and ornithine from citrulline in human colon carcinoma cells: metabolic fate of L-ornithine.

In human colon carcinoma cells (HT-29 cells), L-arginine is the common precursor of L-ornithine which generates polyamines strictly necessary for cellular growth, and nitric oxide which has a strong antiproliferative activity. We show here that proliferative HT-29 cells possess the capacity for de novo synthesis of L-arginine from L-citrulline, but not from L-ornithine. L-Ornithine is apparently not an L-arginine precursor due to the absence of any detectable ornithine carbamoyltransferase activity.

Alpha-difluoromethylornithine (DFMO) as a potent arginase activity inhibitor in human colon carcinoma cells.

Alpha-difluoromethylornithine (DFMO) is commonly used as a specific ornithine decarboxylase (ODC, EC4.1.1.

Differential inhibitory effects of three nitric oxide donors on ornithine decarboxylase activity in human colon carcinoma cells.

Ornithine decarboxylase (ODC, EC 4.1.1.

Effects of L-valine on growth and polyamine metabolism in human colon carcinoma cells.

HT-29 cells, originating from a human colon carcinoma, can proliferate in standard culture conditions with an absolute requirement for polyamines. The major precursor provided in the culture medium for polyamine biosynthesis is L-arginine. L-Arginine conversion to L-ornithine by arginase is followed by stepwise conversion of this latter amino acid to putrescine, spermidine and spermine.