FREE AMINO ACIDS OF BLOOD AND URINE 259 
acids are also excreted in combined form in scurvy. When the deficiency becomes 
more pronounced the picture extends to a generalized aminoaciduria. As in the case 
of vitamin D deficiency, adequate specific therapy easily corrects the situation. 
5) Aminoaciduria in some types of intoxication. Heavy metal (Pb, Hg, U, Cd) 
intoxication may lead to a hyperaminoaciduria but its effects on plasma levels 
still have not been investigated. If the pathogenic process involves the proximal 
convoluted tubule, the picture is that found in the “De Toni-Debré-Fanconi syn- 
drome”. When the process is an endogenous one and when copper is concerned, the 
picture is that of Wilson’s disease, but in this case the process is congenital in nature. 
An experimental “De Toni-Debré-Fanconi syndrome” may be induced in rats 
by intoxication with malic acid and presumably its cause might be a lowering of 
the supply of energy needed for reabsorption, as a result of impaired Krebs cycle 
function in the tubular cells. Other toxic substances, such as lysol, oxalic acid and 
p-aminosalicylic acid have been charged with inducing hyperaminoaciduria. 
A TECHNICAL IMPROVEMENT FOR THE CONTINUOUS COUNTING 
OF LABELED AMINO ACIDS COUPLED WITH ION-EXCHANGE CHROMATOGRAPHY 
The opportunity is taken here to present a new and important technical develop- 
ment brought about by ScHRAM AND LoMBAERT in our department’®. It consists of 


/ / 
to waste or from chromatographic 
analyzer | column or sample tube 




Fi 










50 mm 
Fig. 12. Anthracene cell for the scintillation counting of aqueous solutions. 
a constant volume cell (approx. 1 ml) filled with calibrated anthracene particles’® 
which may be inserted in the line of an ion-exchange chromatography automatic 
machine, by means of special connectors!®, without producing even the least distor- 
tion of the eluted peaks thanks to absence of mixing. It is used for scintillation 
counting of aqueous solution. The counting cell itself is made of transparent 
polyethylene tubing, of approx. 60 cm length filled with anthracene powder and bent 
into a spiral inserted into a flat lucite vial filled with silicone oil, as shown in Fig. 12. 
As the size of anthracene crystals influences both flow resistance and efficiency, 
the mesh size choosen has to be a compromise: 300 yz mesh size were selected for #C 
and 105 w particles for tritium. This counting cell may be used in three different 
References p. 261/262 
