TABLE 5–1 Comparison of Biomarker Attributes (Straume and Lucas 1995)

Biomarker

Human in vivo

in vitro

Animal Model

Inter-Person Variation

Persistence Post-Exposure

Translocationsa

Yes

Yes

Yes

Low

0-lifetime

Dicentrics

Yes

Yes

Yes

Low

0–6 mos.

Micronuclei

Yes

Yes

Yes

High

0–6 mos.

HPRTb

Yes

Yes

Yes

Medium

1 mo.−1 yr.

GPAc

50%

No

No

High

6 mo.-lifetime

TCRd

Yes

No

No

High

1 mo.−2yrs.

HLAe

50%

Yes

No

?

1 mo.−1 yr.

SCEsf

Yes

Yes

Yes

?

0–6 mos.

DNA Adducts

Yes

Yes

Yes

?

0–6 mos.

Protein Adducts

Yes

Yes

Yes

?

0–6 mos.

aReciprocal chromosome translocations.

bHypoxanthine phosphoribosyltransferase assay.

cGlycophorin-A somatic mutation assay.

dT-cell antigen receptor mutation assay.

eHuman leukocyte antigen mutation assay.

fSister chromatid exchanges.

at RERF and for various reasons, some obvious, many have not been suitable for the type of dose determination required.

Despite the promise of FISH and other new assays to produce the assay speed that would allow biodose determination for large numbers of survivors in the RERF study cohort, fewer than 4000 of the over 86,000 in the LSS population currently have biologically-determined doses. Most of these individual doses are derived from the very labor-intensive work with G-banding or from ESR. In addition to the biomarkers compared in Table 5–1, individual exposures to x or gamma radiation can be determined by using electron spin resonance to detect the physical signature left in tooth enamel by irradiation. The ESR signal is proportional to dose between 0.1 and 10 Gy and is independent of photon energy above 200 KeV. As such, ESR signals obtained from the teeth of survivors are good indicators of the doses from the high gamma ray energies released by the A-bombs. This technique has been used successfully to reconstruct dose in some radiation accidents (Pass and others 1997) and at RERF for a limited number of survivors (about 60). The comparison in Figure 5–1 of the dose derived from ESR and chromosome translocations for the same Japanese survivors shows excellent agreement within the uncertainties of these types of assay.

Given the small numbers of biodoses available and the labor currently involved in producing such individual doses, biological dosimetry is not currently a viable alternative to an overall dosimetry system that produces a dose estimate for all of the members of the LSS. Although only a small number of biologically-derived doses for people in the LSS cohort have been determined, these estimates



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