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mg BAIB
mg CREATININE
Figure 47. Urinary BAIB excretion (mg-8-amino-iso-butyric acid per mg
creatinine) versus body load of Cs'*’ (uC), Rongelap inhabitants, 1959.
~
0.06; unexposed, 2.10+0.04). A scatter plot of
Cs'** levels and BAIB levels shows nocorrelation
(Figure 47), and neither does a similar plot between Zn®° levels and BAIB levels. The mean
BAIB excretion level for 18 Micronesians, who
were on Utirik at the time of the atomic explosion
andtherefore not exposed to significant radiation,
was 2.21 +0.13, which is extremely close to the
mean value for the Rongelapese. Amongthe Utirtk people 83% were high excretors, whichis not
significantly different from the Rongelap group
percentage. A numberof complete families are included in the Rongelap sample (i.e., father,
BAIB in man *** and excreted in urine, since no
excretor by high-excretor matings are the only
ones providing significant genetic information.
There were 11 such matings with a total of 31 offspring (29 high excretors and 2 low excretors). One
small dose of radiation, and who have much lower
mother and atleast one child); of these the high-
of the low excretor offspring was illegitimate, as
determined by blood group data, but the otherremains as an unexplained exception to genetic
hypothesis.
Rubini et al.** have recently demonstrated that
BAIB excretors found in Rongelapis due to radiation. The identical average BAIB valuesin the exposed and unexposed groups preclude the possibility that the elevation is due to the fallout exposure in 1954, and it appears that radiation exposure (at the levels received at Rongelap) has no
long-term effect on BAIB excretion. The lack of
correlation with the Cs'*? and Zn® body burdens
rules against the elevation being due to the present
retained internal radiation. The nearly identical
values in the Utirik group whoreceived a very
body burdensof radionuclides, is also consistent
with the thesis that a high incidence of the gene
underlying B-amino-7so-butyric aciduria is responsible for the observed BAIB excretion rate.
The expression of the normal genetic difference 1s
probably dueto differential metabolism of BAIB
by high and low excretors.**
The level of BAIB excretion among the Mar-
radiation exposure. The mechanism involved is
probably the sameas that underlying theeffect of
shallese is the highest yet reported for any population. Blood group*’ and other anthropological
data on these people suggest a Southeast Asiatic
agents markedly increase DNA breakdown; the
thymine thusreleased is effectively converted to
Studies of some Asiatic populations have given
_BAIB excretion can be a sensitive indicator of
nitrogen mustard on BAIB excretion.*? Such
4
appreciable tubular reabsorption of BAIB occurs.** It is unlikely that the high incidence of high
origin; if this is true, a high BAIB level can be
predicted for the populations of that region.
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