The level of aberrant lymphocytes in the blood of rats and duration of survival after radionuclide incorporation

There is a positive correlation between the number of aberrant lymphocytes in the experimental rat blood, 24 h following the administration of 45Ca, 131I, 131I together with 90Sr, and 45Ca together with 137Cs, and the life span of exposed animals. It is suggested that the cytogenetic index should be used in the prognosis of the radionuclide-induced life span shortening.     

On the problem of prophylaxis of late effects induced by internal irradiation using immunomodulators

Using the experimental modeling of late effects induced by intake of radionuclides (131I, 238,239Pu, 90Sr) the attempt to investigate the possibility of protection using immune modulators was made. Co-polymer of 2-methil-5-vinilprilidin and N-vinilpirrholidon (sovidon), G immunoglobulin and interferon, Fc fragment of immunoglobulin and S. parathyphi B. Breslau vaccine were used as immune modulators. The positive prophyletie influence of immune modulators was found for average life span, radiation action, immune status, of rates of occurrence and developments of breast tumors induced by 131I, 239Pu and 90Sr. At the same time the increase in osteosarcoma cumulative rate induced by immune modulators in case of body intake of 238Pu and 90Sr was registered.     

Biochemical changes of the liver in rats with a combined lesion from 89Sr and 131I

The results of the biochemical changes induced by 89Sr and 131I in a rat liver after their separate and combined administration within a wide range of doses are presented. Administered in a combination the radionuclides produced the additive effect when estimated by some indices, and more than additive, according to other tests.     

Bone mineral density in residents of radioactive territories of Chelyabinsk Region

Operation of the Mayak plutonium production association resulted in radioactive contamination of a part of Chelyabinsk Region in the 1950–1960s. Significant gas-aerosol emission of ¹³¹I occurred since 1948; in 1957, a radiation accident resulted in ⁹⁰Sr contamination of large territories. This paper presents comparison of the bone mineral density of persons who lived on territories with different levels of ⁹⁰Sr-soil contamination with that of a control group. It was found that in 1970–1975, the bone mineral density, estimated from the mineral content in bone samples, in residents of contaminated areas born in 1936–1952 was significantly lower compared to the control group. For persons born in 1880–1935, such differences were not found. It was shown that the decrease in the bone mineral density was not related to ⁹⁰Sr exposure of osteogenic cells in the dose range from 0.1 to 1300 mGy: the coefficient of correlation between individual ⁹⁰Sr doses and bone mineral contents is not significant. The decrease in bone mineral density of persons born in 1936–1952 may be associated with exposure of the thyroid and parathyroid glands (systemic regulators of calcium metabolism) to ¹³¹I from gas-aerosol emissions from Mayak. The highest levels of gas-aerosol emissions occurred in 1948–1954 and coincided with the growth and development of the thyroid gland, characterized by intensive accumulation of ¹³¹I, and with the growth and maturation of the skeleton of persons born in the given calendar years.     

Bone mineral density in residents living on radioactive territories of Cheliabinsk Region

Operation of "Mayak" plutonium production complex resulted in radioactive contamination of the part of Chelyabinsk Region in 1950-60s. Significant gas-aerosol emissions of 1311 occurred since 1948; in 1957, a radiation accident resulted in 90Sr contamination of large territories. This paper presents comparison of bone mineral density of persons lived on territories with different levels of soil 90Sr-contamination with a control group. It was found that in 1970-1975 the bone mineral density, estimated from mineral content in bone samples, in residents of contaminated areas born in 1936-1952 was significantly lower compared with the control group. For persons born in 1880-1935 such differences were not found. It was shown that the decrease in bone mineral density was not related to 90Sr exposure of osteogenic cells in the dose range from 0.1 to 1300 mGy: the coefficient of correlation between individual 90Sr-doses and bone mineral contents was not significant. The decrease in bone mineral density of persons born in 1936-1952 could be associated with exposure of thyroid and parathyroid glands (systemic regulators of calcium turnover) by 131I from gas-aerosol emissions from "Mayak". Maximum gas-aerosol emissions occurred in 1948-1954 and coincided with growth and development of thyroid gland, characterizing by intensive accumulation of 131I, and with growth and maturation of the skeleton of persons born in these calendar years.     

Bioluminescent monitoring of NIS-mediated (131)I ablative effects in MCF-7 xenografts

Optical imaging has made it possible to monitor response to anticancer therapies in tumor xenografts. The concept of treating breast cancers with (131)I is predicated on the expression of the Na(+)/I- symporter (NIS) in many tumors and uptake of I- in some. The pattern of (131)I radioablative effects were investigated in an MCF-7 xenograft model dually transfected with firefly luciferase and NIS genes. On Day 16 after tumor cell implantation, 3 mCi of (131)I was injected. Bioluminescent imaging using d-luciferin and a cooled charge-coupled device camera was carried out on Days 1, 2, 3, 7, 10, 16, 22, 29, and 35. Tumor bioluminescence decreased in (131)I-treated tumors after Day 3 and reached a nadir on Day 22. Conversely, bioluminescence steadily increased in controls and was 3.85-fold higher than in treated tumors on Day 22. Bioluminescence in (131)I-treated tumors increased after Day 22, corresponding to tumor regrowth. By Day 35, treated tumors were smaller and accumulated 33% less (99m)TcO(4)(-) than untreated tumors. NIS immunoreactivity was present in <50% of (131)I-treated cells compared to 85-90% of controls. In summary, a pattern of tumor regression occurring over the first three weeks after (131)I administration was observed in NIS-expressing breast cancer xenografts.     

The Incorporation of Orally Administered Radioiodine Into Hens’ Eggs and Follicles

Incorporation of radioiodine into eggs and follicles was studied by oral administration of I131 to hens. With the single dose administration of I131 the shell, including the shell membranes, reached a maximal concentration of 0.017 % of the given amount per g of shell in eggs laid within one day after administration. The white reached a maximal concentration of 0.01 % per g in eggs laid about one day after administration. The subsequent reduction in concentration both in the shell and white from later laid eggs showed a rapid course. In the yolk, radioiodine began to appear in eggs laid about one day after administration. A maximal concentration of 2.78 % of the given amount per yolk was reached in eggs laid about five days after administration. The subsequent reduction in concentration could be followed in the yolk from eggs laid up to and including the ninth day after administration; then the concentration was about 1/50 of the maximal concentration. With continuous administration of I131 once daily for 16 days, the concentration in the shell and white was in the same amount as corresponding maximal concentration in single dose administration as long as the daily supply continued. Following cessation of administration, the concentration decreased in the shell and white with a course simliar to that obtained in the single dose administration. In the yolk, the concentration increased in eggs laid up to and including the ninth day after commencement of the continuous dosing; thereafter, the equilibrium remained as long as the administration continued. About 13 % of the daily given dose of I131 was recovered per yolk. After discontinuation of administration, an obvious concentration reduction was first obtained in the yolks from eggs laid five days later. A calculation of the results for the yolks from the single dose administration to be valid for the daily continuous dosing showed good agreement with the results obtained in the present multiple dose experiments. The follicular uptake of I131 in single dose administration was rapid, with the greatest uptake by the follicle which was in the most rapid phase of growth at the time of administration. During autoradiography of the follicles and eggs following single dose administration of I131, most of the radioiodine was recovered in the growth zone which corresponded to the follicle’s development during the first day after administration.     

Intrathyroidal iodine metabolism in the rat. The influence of diet and the administration of thyroid-stimulating hormone

1. Ratios of mono[¹³¹I]iodotyrosine and di[¹³¹I]iodotyrosine (R values) and the incorporation of ¹³¹I into iodothyronines have been estimated in rat thyroid glands from 30min. to 38hr. after the administration of [¹³¹I]iodide. 2. In rats receiving a powdered low-iodine diet the R values were close to unity and did not change with time after the administration of [¹³¹I]iodide. In rats receiving a commercial pellet diet the R values fell from a mean of 0·8 at 30min. after [¹³¹I]iodide administration to 0·49 at 38hr. 3. Administration of 0·5–2·0i.u. of thyroid-stimulating hormone before giving the injection of [¹³¹I]iodide caused a small diminution in the R value when the time between injecting [¹³¹I]iodide and killing the animal was 16hr. or more. 4. Iodothyronines represented a greater percentage of the total thyroid-gland radioactivity in the iodine-deficient animals than in animals fed on the pellet diet. Thyroid-stimulating hormone had little effect, if any, on the iodothyronine contents.     

Inhibition of thyroid function and thyrotrophic activity following the administration of methallibure (ICI-33 828).

1. Goitrogenic action of methallibure (ICI-33828) has been studied in mice gerbil and hedgehog using thyroid weight and histological structure as an index. Liquefaction and vacuolation of thyroid follicles were most prevelant after methallibure administration. 2. The I131 content of the thyroid gland was significantly higher in the methallibure treated groups than in the controls. This denotes a decrease in the rate of discharge of thyroid hormone. 3. Protein bound radioiodine (Pb I131) was low after methallibure administration. 4. Methallibure administration brings about hypertrophy of pituitary thyrotrophs which is also reflected in the increased basophilic cell percentage in gerbil (control: 15.5 percent; methallibure: 22.8 percent). 5. It is concluded that methallibure acts on thyroid function both by a direct effect on the gland as well as by influencing pituitary thyrotrophic activity in enhancing I131 uptake.     

Secretion of Radioiodine in Milk Following a Single Oral Administration in the Cow

The secretion of radioiodine in the milk following the administration of a single oral dose was studied using I131. All of the values are corrected for the physical decay of the isotope. I131 began to appear in the milk 30 minutes after administration with a maximal concentration of, on the average, 1.7 per cent of the given dose per 1 of milk at about six hours following administration. The subsequent reduction in the concentration showed a two exponential course with biological half-lives of 0.6 days and 10 days, respectively. The total secretion in the milk was between 10 and 27 per cent of the given dose of I131 in six days. The total secretion of radioiodine in the milk was seen to be dependent upon the cow’s milk production.     

Combined lesion in rats from 89Sr and 131I in their repeated uptake into the body

The results are submitted concerning the biological effect of 89Sr and 131I delivered separately and in a combination within a wide dose range. 89Sr has proved to be the major contributor to the effect observed. The effect produced by the radionuclides delivered in a combination was lesser than additive.     

Thyroid cancer after diagnostic administration of iodine-131 in childhood.

Hahn, K., Schnell-Inderst, P., Grosche, B. and Holm, L-E. Thyroid Cancer after Diagnostic Administration of Iodine-131 in Childhood. Radiat. Res. 156, 61-70 (2001).To determine the carcinogenic effects of diagnostic amounts of (131)I on the juvenile thyroid gland, a multicenter retrospective cohort study was conducted on 4,973 subjects who either had been referred for diagnostic tests using uptake of (131)I (n = 2,262) or had had a diagnostic procedure on the thyroid without (131)I (n = 2,711) before the age of 18 years. Follow-up examinations were conducted after a mean period of 20 years after the first examination in 35% of the exposed subjects (n = 789) and in 41% of the nonexposed subjects (n = 1,118). Iodine-131 dosimetry of the thyroid was carried out according to ICRP Report No 53, and the median thyroid dose was 1.0 Gy. In the exposed group, two thyroid cancers were found during 16,500 person-years, compared to three cancers in the nonexposed group during 21,000 person-years. The relative risk for the exposed group was 0.86 (95% CI: 0.14-5.13). The study did not demonstrate an increased risk for thyroid cancer after administration of (131)I in childhood.     

131I uptake in human thyroid after antidote treatment for mixed fission products contamination

The efficacy of a mixed antidote treatment in blocking 131I uptake in humans was investigated in two volunteers. Simultaneous oral administration of 10 g of calcium alginate, 3 g of ferrihexacyanoferrate (II) and 130 mg of potassium iodide 30 min before 131I administration caused an almost complete block of the 131I thyroid uptake in both subjects. This indicated that calcium alginate and ferrihexacyanoferrate (II) had no influence on the blocking effect of potassium iodide on 131I thyroid uptake. This finding is important because mixed antidote treatment is the recommended treatment in cases of accidental exposure to mixed fission products.     

Formation of micronuclei and of clastogenic factor(s) in patients receiving therapeutic doses of iodine-131

The micronucleus (MN) assay in peripheral blood lymphocytes was applied to assess the genotoxic potential of a single dose of iodine-131 (131I) given to six patients for ablation of thyroid remnants after total thyroidectomy. Lymphocytes were taken at various times after 131I therapy (from 2 to 180 days), and evaluated for the presence of MN in the binucleated cells identified after blocking cytokynesis with cytochalasin B. The presence of ultrafiltered, low-molecular weight, clastogenic factor(s) (CFs) in the plasma of 11 patient undergoing 131I therapy was also sequentially assessed.A significantly increased MN frequency was observed in lymphocytes of patients as soon as the first sampling time (2 days after 131I therapy), multifactor analysis of variance (MANOVA): P<0.0001, peaking at day 7 at almost four-fold the spontaneous frequency observed in the pre-therapy samples. MN frequency slowly declined thereafter, reaching the baseline levels at the 180-day time point. When tested against peripheral blood lymphocytes from a healthy donor, the ultrafiltered CFs obtained from 11 patient's plasma induced a significant increase of the MN frequency peaking at day 15. Thereafter, a slow MN frequency decline was observed and the baseline frequency was reached after 180 days. A significant relationship was found between the MN frequency observed in lymphocytes of patients after 131I therapy and the genotoxic CFs activity present in their plasma (P=0.019).These findings suggest that 131I induces a significant increase in the MN frequency of peripheral blood lymphocytes, as well as the formation of transferable CFs which persist for at least 60 days after administration of the radionuclide. The presence of these CFs might be responsible of chromosome aberrations often observed in cultured lymphocytes following X-ray exposure. The possibility of reducing the genotoxic activity of radionuclide therapy by chemoprevention of CFs with antioxidant drugs remains to be explored.     

Human biokinetics of strontium. Part I: Intestinal absorption rate and its impact on the dose coefficient of 90Sr after ingestion

Intestinal absorption of strontium (Sr) in thirteen healthy adult German volunteers has been investigated by simultaneous oral and intravenous administration of two stable tracer isotopes, i.e. (84)Sr and (86)Sr. The measured Sr tracer concentration in plasma was analyzed using the convolution integral technique to obtain the intestinal absorption rate. The results showed that the Sr labeled in different foodstuffs was absorbed into the body fluids in a large range of difference. The maximum Sr absorption rates were observed within 60-120 min after administration. The rate of absorption is used to evaluate the intestinal absorption fraction, i.e. the f (1) value for various foodstuffs. The equivalent and effective dose coefficients for ingestion of (90)Sr were calculated using these f (1) values, and they were compared with those recommended by the International Commission on Radiological Protection (ICRP). The geometric and arithmetic means of the f (1) values are 0.38 and 0.45 associated with a geometric standard deviation and a standard deviation of 1.88 and 0.22, respectively. The 90% confidence interval of the f (1) values obtained in the present study ranges from 0.13 to 0.98. Expressed as the ratio of the 95 and 50% percentiles of the estimated probability, the uncertainty for the f (1) value corresponds to a factor of 2.58. The effective dose coefficients of (90)Sr after ingestion are 6.1 x 10(-9) Sv Bq(-1) for an f(1) value of 0.05, 1.0 x 10(-8) Sv Bq(-1) for 0.1, 1.9 x 10(-8) Sv Bq(-1) for 0.2, 2.8 x 10(-8) Sv Bq(-1) for 0.3, 3.6 x 10(-8) Sv Bq(-1) for 0.4, 5.3 x 10(-8) Sv Bq(-1) for 0.6, 7.1 x 10(-8) Sv Bq(-1) for 0.8, and 7.9 x 10(-8) Sv Bq(-1) for 0.9, respectively. Taking the effective dose coefficient of 2.8 x 10(-8) Sv Bq(-1) for an f (1) value of 0.3, which is recommended by the ICRP, as a reference, the effective dose coefficient of (90)Sr after ingestion varies by a factor of 2.8 when the f (1) value changes by a factor of 3, i.e. it decreases from 0.3 to 0.1 or increases from 0.3 to 0.9, respectively.     

Thyroxine in Early Strobilation in Aurelia aurita

Radiochromatographic studies of ¹³¹I-treated Aurelia polypsrevealed synthesis of three compounds tentatively identifiedas monoiodotyrosine (MIT), diiodotyrosine (DIT), and thyroxine(T₄). One compound, MIT, is found within 8 hr after ¹³¹I administration,before the detection of DIT or T₄ which appear within 24 hr.T₄ is not usually detected after 48 hr although MIT and DITwere found up to the segmentation period. None of the compoundswere detected in ephyrae treated with ¹³¹I for 24 hr. Administration of low dosages of the goitrogens, thiourea,,propylthiouracil, and potassium thiocyanate, in conjunctionwith iodide, prevented strobilation induction. Radiochromatographyof jellyfish given the goitrogens and ¹³¹I revealed a reduceduptake of iodide and an impairment of the synthesis of the iodinatedcompounds. Jellyfish use thyroxine directly for strobilatioa inductionas demonstrated by ¹³¹I - labeled T₄ administration. The T₄was detected in the polyps up to the 48-hr period of strobilationduring which time some of the T₄ was excreted into the medium,as was some ¹³¹I. The fact that T₄, synthesis has thus far been found only instrobilating forms of Aurelia suggests that T₄ is involved primarilywith the differentiation of new structures which occurs duringstrobilation.     

Genetic effects of 131I in reproductive cells of male mice

A study was made of the frequencies of dominant lethal mutations (DLM) in pre- and post-meiotic germ cells, reciprocal translocations (RT) in spermatogonia and abnormal sperm heads (ASH) induced by a single intraperitoneal administration of Na131I with an activity of 1.48-740 kBq/g to male mice. The frequency of DLM was shown to increase only when postmeiotic cells were exposed to the radionuclide. The RT frequency increased insignificantly with increases in the dose of 131I. The ASH frequency increased only when maximal doses of 131I were administered. The relative biological efficiency (RBE) of 131I with reference to the indices under study is less than 1.     

Evaluation of Chlorella as a Decorporation Agent to Enhance the Elimination of Radioactive Strontium from Body

Background

Release of radionuclides, such as ¹³⁷Cs and ⁹⁰Sr, into the atmosphere and the ocean presents an important problem because internal exposure to ¹³⁷Cs and ⁹⁰Sr could be very harmful to humans. Chlorella has been reported to be effective in enhancing the excretion of heavy metals; thus, we hypothesized that Chlorella could also enhance the elimination of ¹³⁷Cs or ⁹⁰Sr from the body. We evaluated the potential of Chlorella as a decorporation agent in vitro and in vivo, using ⁸⁵Sr instead of ⁹⁰Sr.

Methods

In vitro experiments of adsorption of ¹³⁷Cs and ⁸⁵Sr to Chlorella were performed under wide pH conditions. The maximum sorption capacity of Chlorella to strontium was estimated using the Langmuir model. A ⁸⁵Sr solution was orally administrated to mice pretreated with Chlorella. At 48 h after ⁸⁵Sr administration, the biodistribution of radioactivity was determined.

Results

In the in vitro experiments, although ⁸⁵Sr barely adsorbed to Chlorella at low pH, the ⁸⁵Sr adsorption ratio to Chlorella increased with increasing pH. The maximum sorption capacity of Chlorella to strontium was 9.06 mg / g. ¹³⁷Cs barely adsorbed to Chlorella under any pH conditions. In the biodistribution experiments, bone accumulation of radioactivity after ⁸⁵Sr administration was significantly decreased in the Chlorella pretreatment group compared with the non-treatment control group.

Conclusions

In conclusion, these results indicated that Chlorella could inhibit the absorption of ⁹⁰Sr into the blood and enhance the elimination of ⁹⁰Sr from the body through adsorption in intestine. Further studies are required to elucidate the mechanism and the components of Chlorella needed for adsorption to strontium and could promote the development of more effective decorporation agents.     

The dependence of accumulation of 137Cs and 90Sr radionuclides in the forages cultivation degree of sod-podzolic soils

For prognosis of accumulation of 137Cs and 90Sr in forages harvested in radionuclide contaminated sod-podzolic soils, it is suggested to use transfer factors (TF9a) (Bq/kg)/(kBq/m2)) established not only by the content of mobile potassium (137Cs, r = -0.53) and the value of exchange acidity (90Sr, r = -0.73), but also by the index of agrochemical soil cultivation I(cd) (137Cs, r = -0.69; 90Sr, r = -0.64). The possibility of obtaining forages conforming to the state standards on the haymaking and pasture areas with high density of radioactive contamination of soils was shown by the example of "Sudkovo" collective farm. The approach is based on achievement of a high degree of cultivation (l(cd) - 0.81-1.0) due to a complex of protective measures, which resulted in a 10-fold decrease in the specific activity of 137Cs and a 4-fold decrease in the activity of 90Sr, compared to the soils with a low degree of cultivation (I(cd) - 0.41-0.60).     

A Case of Esophageal Stricture After Iodine 131 Ablation

ObjectiveTo report the first case of esophageal stricture as a complication of radioiodine (¹³¹I) ablation therapy.MethodsWe review the medical and surgical history of this patient and discuss various potential causes of the esophageal stricture.ResultsA 79-year-old woman presented with increasing dysphagia and weight loss of about 4.5 kg after recent ¹³¹I therapy for thyroid cancer remnant ablation. Her pertinent history included gastroesophageal reflux disease, an anterior midcervical esophageal web, and a distal esophageal stricture. She also had a history of radiation therapy to her chest for breast cancer about 28 years previously. On the day of ¹³¹I therapy, the 5.5-GBq ¹³¹I capsule lodged accidentally in her midcervical area for approximately 2.5 hours. The resulting radiation dose to the proximal esophagus was estimated to be 7.86 Gy from gamma radiation and possibly as high as several thousand grays from beta radiation. During this time, the esophagus had possible direct exposure to the sodium phosphate dibasic that was used as filler in the sodium iodide capsule. Because of the worsening dysphagia, an esophagogastroduodenoscopy was performed 4 weeks after the ¹³¹I therapy, which showed a new proximal esophageal stricture.ConclusionWe believe that the additional localized radiation and sodium phosphate exposure from the lodging of the ¹³¹I capsule may have contributed to the development of a proximal esophageal stricture. To our knowledge, such an occurrence has not previously been described in the medical literature. For prevention of such an occurrence, we recommend a careful swallowing evaluation of patients with any history of esophageal radiation exposure, dysphagia, or esophageal strictures before administration of ¹³¹I in capsule form. Alternative methods of ¹³¹I delivery, if available, should be considered. (Endocr Pract. 2012;18: e61-e64)