Fig. 4.

Formaldehyde levels in C57BL/6 J mice after administration ofd-ribose. Mice (n = 14 in each group) were injected (i.p.) with d-ribose series (rib, 3.2 g/kg•d), d-glucose (glc, 3.82 g/kg•d), and saline (0.9% NaCl in double-distilled water) as a control (ctrl) daily for 10 days, followed by the measurement of formaldehyde in the brain (a), serum (b), with 1.0 g/l 2,4-dinitrophenylhydrazine (DNPH) by HPLC, as described in the text. All of the values are expressed as the mean ± S.E.M. *p < 0.05, n = 8.