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exposure of NDT workers. LAR was estimated based on the BEIR VII model with the baseline cancer
incidence rates and the life table in 2011 for South Korean male. Estimated LARs (per 100) for doses
(mSv/yr) of 10, 20 and 30 were 3.2, 6.3 and 9.5 for all solid cancers combined. Compared with lifetime
baseline risk, lifetime fractional risk (LFR) was estimated at 6.3-18.9% for the dose range of 10-30
mSv/year for all solid cancers combined. The exposure limit of radiation workers in South Korea is 100
mSv per 5 yr (not exceed 50 mSv per 1 yr). If those who were exposed to 30 mSv/yr for the first three
years of their employment are managed with the exposure limit of 100 mSv per 5 yr (e.g., 10 mSv for the
next two years and 20 mSv/yr thereafter until age 55), their LAR for all solid cancers would decrease by
33% compared with continuous exposure of 30 mSv/yr for the entire employment without any
appropriate measures. Since the risk of relatively high dose exposure is observed to be greater in NDT
workers in South Korea, they need more careful and continuous monitoring.
(PS7-3) Activation of de novo glutathione synthesis pathway on mouse spleen after low-dose gamma-
ray irradiation. Tae Gen Son, Dongnam Institute of Rdiological and Medical Science, Busan, Korea,
Republic of
Glutathione (GSH) is an important cellular antioxidant and has a critical role in maintaining the
balance of cellular redox. In this study, we investigated the GSH biosynthesis genes involved in the
elevation of endogenous GSH levels using an irradiation system with an irradiation dose rate of 1.78
mGy/h, which was about 40,000 times less than the dose rates used in other studies. The results showed
that GSH levels were signifi cantly increased in the low-dose (0.02 and 0.2 Gy) irradiated group compared
to those in the non-irradiated group, but enzymatic antioxidants such as superoxide dismutase and
catalase were not induced at any doses tested. The elevation in GSH was accompanied by elevated
expression of glutamate - cysteine ligase modifi er subunit, but no changes were observed in the
expression of glutamate – cysteine ligase catalytic subunit and thioredoxin in de novo GSH synthesis. In
the case of genes involved in the GSH regeneration cycle, the expression of glutathione reductase was not
changed after irradiation, whereas glutathione peroxidase was only increased in the 0.2 Gy irradiated
group. Collectively, our results suggest that the de novo pathway, rather than the regeneration cycle, may
be mainly switched on in response to stimulation with long-term low-dose radiation in the spleen.
1
(PS7-4) A natural history exploratory study of GI-ARS in the Gottingen minipig. Maria Moroni ; Deutz
1
2
1
1
3
1
Nicolaas ; Jatinder Gulani ; Amory koch ; Cara Olsen ; Christine Christensen ; Mark Chappell ; Mark
1
1
1
Whitnall ; and Thomas Elliott , Armed Forces Radiobiology Research Institute, Bethesda, MD ; Texas A&M
2
University, College Station, TX ; and USUHS, Bethesda, MD
3
In the absence of supportive care, lethality from the hematopoietic syndrome in the Gottingen
minipig is achieved at doses below 2 Gy. Additionally, in the dose range between 2 and 5 Gy, an
accelerated hematopoietic syndrome occurs, characterized by villus blunting and fusion, the beginning of
sepsis, and a mild, transient reduction in plasma citrulline concentration. In levels up to 5 Gy, though, the
classic signs of gastrointestinal (GI) damage, characterized by vomiting, diarrhea, loss of crypts, bacterial
translocation, and a drop in plasma citrulline levels, are absent. Reasonable concern over the feasibility
of inducing classic gastrointestinal acute radiation syndrome (GI-ARS) in the minipig, prior to lethality
related to cardio-vascular and respiratory complications, prompted us to test doses of 5 Gy and above.
353 | P a g e
incidence rates and the life table in 2011 for South Korean male. Estimated LARs (per 100) for doses
(mSv/yr) of 10, 20 and 30 were 3.2, 6.3 and 9.5 for all solid cancers combined. Compared with lifetime
baseline risk, lifetime fractional risk (LFR) was estimated at 6.3-18.9% for the dose range of 10-30
mSv/year for all solid cancers combined. The exposure limit of radiation workers in South Korea is 100
mSv per 5 yr (not exceed 50 mSv per 1 yr). If those who were exposed to 30 mSv/yr for the first three
years of their employment are managed with the exposure limit of 100 mSv per 5 yr (e.g., 10 mSv for the
next two years and 20 mSv/yr thereafter until age 55), their LAR for all solid cancers would decrease by
33% compared with continuous exposure of 30 mSv/yr for the entire employment without any
appropriate measures. Since the risk of relatively high dose exposure is observed to be greater in NDT
workers in South Korea, they need more careful and continuous monitoring.
(PS7-3) Activation of de novo glutathione synthesis pathway on mouse spleen after low-dose gamma-
ray irradiation. Tae Gen Son, Dongnam Institute of Rdiological and Medical Science, Busan, Korea,
Republic of
Glutathione (GSH) is an important cellular antioxidant and has a critical role in maintaining the
balance of cellular redox. In this study, we investigated the GSH biosynthesis genes involved in the
elevation of endogenous GSH levels using an irradiation system with an irradiation dose rate of 1.78
mGy/h, which was about 40,000 times less than the dose rates used in other studies. The results showed
that GSH levels were signifi cantly increased in the low-dose (0.02 and 0.2 Gy) irradiated group compared
to those in the non-irradiated group, but enzymatic antioxidants such as superoxide dismutase and
catalase were not induced at any doses tested. The elevation in GSH was accompanied by elevated
expression of glutamate - cysteine ligase modifi er subunit, but no changes were observed in the
expression of glutamate – cysteine ligase catalytic subunit and thioredoxin in de novo GSH synthesis. In
the case of genes involved in the GSH regeneration cycle, the expression of glutathione reductase was not
changed after irradiation, whereas glutathione peroxidase was only increased in the 0.2 Gy irradiated
group. Collectively, our results suggest that the de novo pathway, rather than the regeneration cycle, may
be mainly switched on in response to stimulation with long-term low-dose radiation in the spleen.
1
(PS7-4) A natural history exploratory study of GI-ARS in the Gottingen minipig. Maria Moroni ; Deutz
1
2
1
1
3
1
Nicolaas ; Jatinder Gulani ; Amory koch ; Cara Olsen ; Christine Christensen ; Mark Chappell ; Mark
1
1
1
Whitnall ; and Thomas Elliott , Armed Forces Radiobiology Research Institute, Bethesda, MD ; Texas A&M
2
University, College Station, TX ; and USUHS, Bethesda, MD
3
In the absence of supportive care, lethality from the hematopoietic syndrome in the Gottingen
minipig is achieved at doses below 2 Gy. Additionally, in the dose range between 2 and 5 Gy, an
accelerated hematopoietic syndrome occurs, characterized by villus blunting and fusion, the beginning of
sepsis, and a mild, transient reduction in plasma citrulline concentration. In levels up to 5 Gy, though, the
classic signs of gastrointestinal (GI) damage, characterized by vomiting, diarrhea, loss of crypts, bacterial
translocation, and a drop in plasma citrulline levels, are absent. Reasonable concern over the feasibility
of inducing classic gastrointestinal acute radiation syndrome (GI-ARS) in the minipig, prior to lethality
related to cardio-vascular and respiratory complications, prompted us to test doses of 5 Gy and above.
353 | P a g e
