Effects of barbiturates on facilitative glucose transporters are pharmacologically specific and isoform selective.

Barbiturates inhibit GLUT-1-mediated glucose transport across the blood-brain barrier, in cultured mammalian cells, and in human erythrocytes. Barbiturates also interact directly with GLUT-1. The hypotheses that this inhibition of glucose transport is (i) selective, preferring barbiturates over halogenated hydrocarbon inhalation anesthetics, and (ii) specific, favoring some GLUT-# isoforms over others were tested. Several oxy- and thio-barbiturates inhibited [3H]-2-deoxyglucose uptake by GLUT-1 expressing murine fibroblasts with IC50s of 0.2-2.9 mm. Inhibition of GLUT-1 by barbiturates correlates with their overall lipid solubility and pharmacology, and requires hydrophobic side chains on the core barbiturate structure. In contrast, several halogenated hydrocarbons and ethanol (all 10 mm). Thus, barbiturates selectively inhibit glucose transport by some, but not all, facilitative glucose transporter isoforms.

[Meaning of pleocytosis in spinal fluid in children with neoplasias]. / Significado de la pleocitósis del LCR en niños con neoplasias.

Thirty-five spinal fluids with leucocytosis belonging to 26 children presenting neoplasia without metastases or CNS infection, were studied. We found that 69% of the cases were receiving some kind of CNS therapy, although leucocytosis could be found at any moment of the evolution and independently of treatment. It is stressed that the criteria for meningeal infiltration in children with neoplasia must be established only if tumoral cells are found in the spinal fluid. Pleocytosis and absence of symptomatology must not be used as the main criteria.