 from the bilateral plane. When regions within 30 degrees of the dorsal midline are excluded from recombinants, ventralized embryos develop lacking the entire anterior-posterior sequence of dorsal structures, suggesting that the organizer is only 60 degrees wide (centered on the dorsal midline) at the late blastula stage. As more and more dorsal MZ (organizer) is included in the recombinant, progressively more anterior dorsal structures are formed. In all cases, when any dorsal structures are missing they are deleted serially from the anterior end. Thus, we suggest that the amount (lateral width) of the organizer in the MZ determines the anterior extent of dorsal development.

Frontal auditory-evoked potential augmenting-reducing and urinary homovanillic acid.
Relationships between augmenting-reducing (Aug/Red) in auditory modality and dopaminergic metabolism were investigated in young adults with respect to sex. The slope values of evoked potential amplitude changes with increasing intensities were used to evaluate Aug/Red both at Cz and Fz for each of the five components: P1, N1, P2, P1N1, N1P2. The greatest slopes (Aug) were found in females. Individual differences in dopaminergic metabolism were estimated by assaying free and conjugated forms of homovanillic acid (HVA) in urines. HVA excretion rates were significantly more variable in males than in females. Relationships between Aug/Red and HVA levels were only found in males. The lower the Aug/Red slopes recorded at Fz site for the N1 component (weak augmenter or reducer responses), the higher the urinary HVA level and particularly the conjugated forms of HVA. These results are of interest for further applications in psychopathology.

The liver in GM1 gangliosidosis types 1 and 2. A light and electron microscopical study.
The livers from two cases of GM1 gangliosidosis types 1 and 2 were examined by histochemistry, light and electron microscopy. Type 1 GM1 gangliosidosis is characterized by large amounts of a water soluble substance in the hepatocytes, presu