378 G. ROUSER et al. 
Erythrocyte free amino acids 
A number of examples of the free amino acid pools of erythrocytes in chronic granu- 
locytic leukemia are presented in parts I, V and VI of this series. Figs. gI-93 show 
three erythrocyte samples drawn from the same normal individual on the same day. 
The cells shown in Fig. 92 were obtained from a blood sample drawn 30 min after the 
cells shown in Fig. 91, while cells shown in Fig. 93 were obtained from blood drawn 
th after the blood sample shown in Fig. 92. The aliquot size is equivalent to 0.5 ml 
of packed red cells and shows quite clearly the free amino acid pool constituents of 
normal erythrocytes listed in the first paper of this series. Erythrocytes contain more 
free glutamate and aspartate than plasma. Note that Figs. g1-93 show the presence 
of a-amino n-butyric acid, proline, histidine, arginine, and ethanolamine-O-phosphate 
in normal erythrocytes. The marked similarity of the free amino acid pool of erythro- 
cytes obtained from blood samples drawn on the same day demonstrates the repro- 
ducibility of the methods employed. It was observed that the same individual, whether 
normal or leukemic, showed some fluctuations of the erythrocyte free amino acid pool 
constituents from one day to the next, and that differences were more marked when 
samples were spaced at weekly or monthly intervals. Taurine is a highly variable con- 
stituent of both plasma and erythrocytes, and many erythrocyte samples do not show 
the presence of the small amount of ethanolamine-O-phosphate seen in other samples. 
No consistent differences could be observed between erythrocyte free amino acid 
pools of normal individuals and patients with granulocytic leukemia. The variability 
of the free amino acid pools of both groups makes such comparisons difficult. It 
appeared that the erythrocyte free amino acid pools tended to be greater when the 
plasma levels of free amino acids were elevated in granulocytic leukemia. This was 
not, however, an invariable finding. Erythrocytes do not always respond to amino 
acid pool changes of plasma. The failure of erythrocytes to reflect plasma changes 
was observed after drug therapy and amino acid ingestion and will be discussed later. 
Atypical findings 
We have generally observed deviations from the more or less typical findings with 
plasma and cells of untreated patients after administration of cytotoxic drugs. 
Figs. 94-96 illustrate the findings in plasma, erythrocytes, and leukocytes of a blood 
sample from a patient (R.San.) with chronic granulocytic leukemia diagnosed 
5 years prior to the time of sampling. The patient had received extensive myleran 
and X-ray therapy and 3 days before the blood sample was drawn had received 
400 ml of fresh whole blood. The plasma sample (Fig. 94) from this patient had an 
extremely low glutamic acid level. A reduction in plasma glutamate occurs regularly 
after drug therapy and is considered in detail in the discussion of the effects of 
myleran and dimethylmyleran (part V). The erythrocyte free amino acid pool 
(Fig. 95) is of considerable interest in that glutathione is far above the levels seen in 
untreated patients. Fig. g6 shows leukocyte free amino acids that are distinctly 
different from the usual cell population of this type (the patient had a leukocyte 
count of 142 000/mm? with 42°, polymorphonuclear leukocytes, 28% myelocytes 
and metamyelocytes, 7°/, promyelocytes, 3°{ myeloblasts, 5°% eosinophils, and 
15% basophils). The leukocyte ethanolamine-O-phosphate level is very high while 
the taurine level is lower than the level usually encountered. Erythrocytes may 
contain taurine when it is not observed in the blood plasma (Figs. 94 and 95). This 
References p. 447/448 
