Am J Clin Nutr. 2005
Mar;81(3):656-63. Changes in iodine excretion in 50-69-y-old
denizens of an Arctic society in transition and iodine excretion
as a biomarker of the frequency of consumption of traditional Inuit
foods.
Andersen S, Hvingel B, Kleinschmidt K, Jorgensen T, Laurberg P.
Department of Endocrinology and Medicine, Aalborg Hospital, Aarhus
University Hospital, Denmark and Surgery, Queen Ingrids Hospital,
Nuuk, Greenland.
BACKGROUND: Iodine intake in Greenland has been hypothesized to
exceed 10 times the recommended amount. The transition from a traditional
Arctic society may change the iodine intake, but no field studies
have been performed. OBJECTIVE: We aimed to ascertain iodine intakes,
factors affecting iodine intake in circumpolar populations, and
the usefulness of urinary iodine excretion as a biomarker for validation
of Inuit food-frequency questionnaires. DESIGN: Data were collected
in a cohort study of 4 Greenland population groups: Inuit living
in the capital city, the major town, and settlements in East Greenland
and non-Inuit. Supplement use and lifestyle factors were evaluated
with questionnaires, and dietary habits were ascertained with a
food-frequency questionnaire. Iodine was measured in spot urine
samples. RESULTS: One percent of the population of Greenland was
invited, and the participation rate was 95%. Less than 5% of Inuit
but 55% of non-Inuit had urinary iodine excretion < 50 mug/24
h. Median urinary iodine excretion declined with the degree of decrease
in the traditional lifestyle: it was 198, 195, 147, and 58 mug/24
h among Inuit in settlements, town, and city and in non-Inuit, respectively
(P < 0.001). Participants were divided into diet groups calculated
from Inuit food frequency. Iodine excretion decreased with increasing
intake of imported foods (P < 0.001). In regression models, type
of diet and the subject's lifestyle, sex, weight, ethnicity, and
intake of iodine-containing supplements affected urinary iodine
excretion. CONCLUSIONS: Circumpolar non-Inuit are at risk of iodine
deficiency. Departure from the traditional Inuit diet lowers iodine
intake, which should be monitored in Arctic societies. Urinary iodine
excretion may be a useful biomarker of traditional Inuit food frequency.
Toxicology. 2003 Jul 15;189(1-2):1-20. Protection against ionizing radiation
by antioxidant nutrients and phytochemicals.
Weiss JF, Landauer MR.
Office of Health Studies, US Department of Energy, EH-6/270 Corporate
Square, 1000 Independence Avenue, SW, Washington, DC 20585-0270,
USA.
The potential of antioxidants to reduce the cellular damage induced
by ionizing radiation has been studied in animal models for more
than 50 years. The application of antioxidant radioprotectors to
various human exposure situations has not been extensive although
it is generally accepted that endogenous antioxidants, such as cellular
non-protein thiols and antioxidant enzymes, provide some degree
of protection. This review focuses on the radioprotective efficacy
of naturally occurring antioxidants, specifically antioxidant nutrients
and phytochemicals, and how they might influence various endpoints
of radiation damage. Results from animal experiments indicate that
antioxidant nutrients, such as vitamin E and selenium compounds,
are protective against lethality and other radiation effects but
to a lesser degree than most synthetic protectors. Some antioxidant
nutrients and phytochemicals have the advantage of low toxicity
although they are generally protective when administered at pharmacological
doses. Naturally occurring antioxidants also may provide an extended
window of protection against low-dose, low-dose-rate irradiation,
including therapeutic potential when administered after irradiation.
A number of phytochemicals, including caffeine, genistein, and melatonin,
have multiple physiological effects, as well as antioxidant activity,
which result in radioprotection in vivo. Many antioxidant nutrients
and phytochemicals have antimutagenic properties, and their modulation
of long-term radiation effects, such as cancer, needs further examination.
In addition, further studies are required to determine the potential
value of specific antioxidant nutrients and phytochemicals during
radiotherapy for cancer.
Acta Oncol. 1994;33(2):139-57. On radiation damage to normal tissues
and its treatment. II. Anti-inflammatory drugs.
Michalowski AS.
MRC Cyclotron Unit, Hammersmith Hospital, London, UK.
In addition to transiently inhibiting cell cycle
progression and sterilizing those cells capable of proliferation,
irradiation disturbs the homeostasis effected by endogenous mediators
of intercellular communication (humoral component of tissue response
to radiation). Changes in the mediator levels may modulate radiation
effects either by assisting a return to normality (e.g., through
a rise in H-type cell lineage-specific growth factors) or by aggravating
the damage. The latter mode is illustrated with reports on changes
in eicosanoid levels after irradiation and on results of empirical
treatment of radiation injuries with anti-inflammatory drugs.
Prodromal, acute and chronic effects of radiation are accompanied
by excessive production of eicosanoids (prostaglandins, prostacyclin,
thromboxanes and leukotrienes). These endogenous mediators of
inflammatory reactions may be responsible for the vasodilatation,
vasoconstriction, increased microvascular permeability, thrombosis
and chemotaxis observed after radiation exposure. Glucocorticoids
inhibit eicosanoid synthesis primarily by interfering with phospholipase
A2 whilst non-steroidal anti-inflammatory drugs prevent prostaglandin/thromboxane
synthesis by inhibiting cyclooxygenase. When administered after
irradiation on empirical grounds, drugs belonging to both groups
tend to attenuate a range of prodromal, acute and chronic effects
of radiation in man and animals. Taken together, these two sets
of observations are highly suggestive of a contribution of humoral
factors to the adverse responses of normal tissues and organs
to radiation. A full account of radiation damage should therefore
consist of complementary descriptions of cellular and humoral
events. Further studies on anti-inflammatory drug treatment of
radiation damage to normal organs are justified and desirable.
Med Pediatr Oncol. 2002 Jan;38(1):41-6. Thyroidal uptake and radiation dose
after repetitive I-131-MIBG treatments: influence of potassium iodide
for thyroid blocking.
Brans B, Monsieurs M, Laureys G, Kaufman JM, Thierens H, Dierckx
RA.
Division of Nuclear Medicine, Ghent University Hospital, Belgium.
BACKGROUND: In I-131-MIBG therapy, I-131-iodide can be released
from the I-131-MIBG molecule. Hypothyroidism might result from the
undesirable irradiation of the thyroid gland. To prevent this, stable
iodide such as potassium iodide (KI) is given to oversaturate the
thyroid before I-131-MIBG is administered. PROCEDURE: In the present
study, the incidence of hypothyroidism (elevated TSH) was correlated
with the thyroidal uptake of I-131 and dose (MIRD dosimetry) after
35 individual treatments in ten patients. Iodine-131-MIBG therapy
was performed using a modified dosage of 1.9-11.1 GBq (50-300 mCi)
IV. Premedication with KI was done as recommended with a dose of
100 mg KI orally from 2 days before until 4 weeks after I-131-MIBG.
RESULTS: The absorbed thyroidal dose amounted to a very variable
range of 0.2 (patient # 1) up to 30.0 (patient 3) Gy with 7.1 +/-
7.9 Gy per treatment and 24.1+/- 19.2 Gy per patient (mean+/- SD),
despite the same and compliantly taken KI premedication protocol.
Up to now, 4/10 or 40% of patients have developed hypothyroidism
after a mean follow-up period of 11 months and a mean total administered
dose of 18.7 GBq (505 mCi). A trend towards higher thyroidal doses
was seen in the hypothyroid patients. CONCLUSIONS: This study observes
a general high inter- and intra-individual variability in radio-iodide
uptake in the thyroid after I-131-MIBG therapy despite KI premedication,
as well as possible occurrence of hypothyroidism. A dose-response
relationship needs confirmation on a larger cohort of patients to
reach statistical value. An alternative thyroid cytoprotection strategy
for possible long-term survivors may be considered.
