Radioactive Iodine 131I Research Articles

Implantation of homologous and heterologous aortic valves in prosthetic vascular tubes.

<h3>OBJECTIVE:</h3> This study was performed to evaluate the efficacy of radioactive iodine 131I therapy of Graves9 hyperthyroidism at Sultan Qaboos University Hospital, Oman and to determine the optimal dose of 131I needed to achieve the euthyroid or hypothyroid status. <h3>METHODS:</h3> The medical records of 366 patients with Graves hyperthyroidism who received a single dose of 131I at Sultan Qaboos University Hospital, Oman between 1991 and 1999 were reviewed. The diagnosis was based on clinical, biochemical grounds and 99mTc thyroid scintigraphy. The patients were followed up for a minimum period of 12 months. For the analysis, the patients were divided into 6 groups according to the 131I dose administered: Dose one (350-399), dose 2 (400-449), dose 3 (450-499), dose 4 (500-549), dose 5 (550-599) and dose 6 (&gt;=600) MBq. <h3>RESULTS:</h3> Fifty-eight percent of all the patients were hypothyroid after 3 months. Three hundred and twenty two patients (88%) were treated by a single dose of 131I in 12 months (85.5% hypothyroid and 2.5% euthyroid). Forty-one patients (11.2%) required a 2nd 131I dose and only 3 patients required 3 doses of 131I. The best cure rate (93%) was observed in group dose 5 (574.0 ± 16.4 MBq) which however, was not significantly different from other dosage levels. The female to male ratio was 2:1 and the cure rates were not gender or age related. <h3>CONCLUSION:</h3> Treatment of Graves9 hyperthyroidism from a single 131I dose is our aim, rather than avoidance of hypothyroidism. Our results indicate that cure rates are higher with larger doses of 131I except in group dose 6 (special category of patients). In the future, fixed doses would be adopted in our radioactive iodine treatment practice guidelines. As the majority of our patients were hypothyroid at 3 months regular monthly follow-up is essential. Whenever appropriate, physicians are encouraged to consider early referral of Graves9 hyperthyroidism patients for radioactive iodine treatment as it is cheap, effective, easy to administer and free from serious side effects.

Measurement of Early Uptake of Radioactive Iodine I131 by Thyroid Gland: Method Requiring Reduced Irradiation

Measurement of Early Uptake of Radioactive Iodine I131 by Thyroid Gland: Method Requiring Reduced Irradiation

Paper electrophoresis of aqueous humour proteins labelled with radioactive iodine 131I

A simple method for the iodination of proteins of the aqueous humour with radioactive iodine 131I is described. After iodination of the proteins with radioactive iodine the aqueous humour is analysed by electrophoresis on paper strips saturated with calf-serum in veronal buffer of pH 8.5 with ionic strength of 0.07 μ at a potential drop of 3 V cm−1. The time of electrophoresis is 18 hr. The electrophoreograms are dried and washed three times with a solution of acetic acid in dilute ethylalcohol, dried again and evaluated by direct measurement of the radioactivity of the 131I ohemically bound to proteins of the aqueous humour or by photometric measurement of the autoradiograms obtained by contact exposure of the eleotrophoreograms on X-ray film. The method is very sensitive; it is therefore sufficient to use 10 to 20 μl of aqueous humour for the iodination. Ten to 20 μ of the iodinated aqueous humour, i.e. 4 to 8 μl of the original aqueous humour with a protein content of 2 to 5 μg are applied to the paper. The results of the eleotrophoretic analysis of human, rabbit and bovine aqueous humour are in good agreement with the results of analogous analyses carried out by other methods.

A slide rule cursor for radioactive isotope calculations.

In the investigation of thyroid gland function the uptake of radioactive iodine 131I in the gland is frequently measured at fixed times during the first 48 hours after the administration of a tracer dose.

Thyrocardiac disease and its management with radioactive iodine I-131.

Hyperthyroidism was treated with I131 in 1,603 cases. These included cases of diffuse toxic goiter and nodular goiter with hyperthyroidism. There were 187 patients with congestive heart failure, 30 with angina pectoris, and 32 with combined angina pectoris and congestive failure. In addition, there were 107 patients with atrial fibrillation but without congestive failure or angina. Radioiodine was the only treatment used for the hyperthyroid state. The cardiac status was strikingly improved in all groups studied. The number of treatments and incidence of myxedema was almost the same for the cardiac and noncardiac patients. The total administered dose averaged 7.0 millicuries for the entire series and 11.5 for the cardiac patients. The recurrence rate was less than 1%. The authors believe that I¹³¹is the treatment choice for thyrocardiac disease.

CHANGES OF THYROID FUNCTION IN RESPONSE TO SEVERE NERVOUS STIMULATION

ABSTRACT The effect of prolonged exposure to severe nervous traumatization on the activity of the thyroid gland has been studied. Good agreement between the results was obtained by using radioactive iodine 131I, measuring the activity over the thyroid gland and the radioautographs, as well as doing the histological examinations and determinations of the height of the epithelial cells lining the acini. According to these results intense nervous stimulations have a characteristic effect on the thyroid function. The initial phase of hyperfunction, lasting under our experimental conditions for 10 days, is followed by a state characterized by hypofunction. The effect is reversible. This effect of severe nervous traumatization on the thyroid function is markedly inhibited by chlorpromazine.

Studies on Offsprings of Rats (F&lt;SUB&gt;1&lt;/SUB&gt;-F&lt;SUB&gt;4&lt;/SUB&gt;) Born from Ancestors Radio-thyroidectomized on Successive Generations

Choosing albino rats of the Wistar strain for study, the author destructed the thyroid glands of the rats of both sexes using radioactive iodine I131, crossed them above 1 month later and made them sire litters (F1). The destruction of thyroids of the young, both male and female, was achieved 3 months after birth in a similar manner that their parents were treated, mated above 1 month post-administration and made to give birth to the F2 offsprings. The same procedure was conducted on four generations till the fourth descendants were obtained thereby, scheming to explore the influence of radiothyroidectomized state upon the descendants of successive four generations. On the offspring rats F1 (26 cases), F2 (26 cases), F3 (29 cases) and F4 (40 cases), each generation was subjected to the study of growth rate by determining body weights, to the comparative study of the weights of splanchnic organs at a definite time post partum, to the histological and histometrical investigations of thyroids and other splanchnic organs and was rendered to the measurements of their serum PBI, of serum total cholesterol and of the rate of thyroid uptake of I131 and to the comparison with those of the control animals (25 cases), yielding the following results : (1) From the results of the measurement of body weights, it was revealed that the gain in body weights as compared to those of controls was reduced by degrees as the generation went down.(2) The ratio of thyroid-to body weights tended to increase as the generation descended.(3) In the picture of thyroid glands, follicles grew larger on and on, follicular cavities were filled with colloids, became to take up much eosin and PAS dye and the formation of peripheral vacuolation were depressed as the descent of generation went on.Follicle cells went on flattening, PAS granules seen in follicle cells were decreased in number parallel to the descent of generation, and the majority of follicle cells were found to present a similar appearance to that of endothelial cells.(4) From the histometrical examination of thyroids, the following results were obtained a) Follicle areas measured 5012±524μ2 in controls, 5645±539μ2 in F1, 6539±846μ2 in F2, 7048±863μ2 in F3 and 7513±1048μ2 in F4, tending to grow larger as the generation descended.b) Areas of follicle cavity were of the dimension of 2468±498 in controls, 3527±654μ2 in F1, 4457±526μ2 in F2, 5403±322μ2 in F3 and 6086±676μ2 in F4 which shows that the value of controls was about one half that of F4.c) Areas of follicle cells ranged to 129.3±16.7μ2 in controls, 108.6±25.6μ2 in F1, 96.1±21.2μ2 in F2, 75.9±12.4μ2 in F3 and 66.0±11.7μ2 in F4, which means the fall on successive generations.d) Follicle cells were of the height of 7.7±0.585μ in controls, 6.8±0.937μ in F1, 6.1±0.789μ in F2, 5.3±0.603μ in F3 and 4.4±0.44μ in F4, showing a tendency to an apparent decrease on consecutive descent of generations.e) Cell counts per follicle cell amounted 19.9±2.53 in controls, 20.3±2.41 in F1, 20.3±3.96 in F2, 21.6±2.26 in F3 and 20.7±2.53 in F4, minor changes being observed in cell counts.

Experimental Studies on essential cause for the sexual difference of the thyroid function

It has been clincically known that thyroid diseases are seen more frequently in the female than in the male. However, the sexual differences are not as yet fully explained. For this purpose, effects of castration on the thyroid function and effects of gonadal steroid hormones on the thyroid function of the castrate mature rats of both sexes were investigated. For determination of the thyroid function, radioactive iodine I131 was used and remarkable findings were obtained.The results are summarized as follows : 1) Effects of castration on the thyroid function were manifested by hypofunction, usually, 14 days in the female and 42 days in the male, after castration, and greater changes were found in females than in males, and the effects were persisted even 2 months after the castration. It may be concluded that those greater changes in females without distinction to post-operative period had apparently indicated the fact that there are substantial differences of the thyroid function between male and females.2) It is the matter of course that sexual differences should be looked for in the gonads. But, for the explanation of this mechanism, 3 kinds of steroid hormones ; estradiol benzoate, progesterone, and testosterone propionate were administered to the castrated mature rats and these effects on the thyroid function were examined. Marked differences have been found to exist between two sexes.(1) Estrogen has an accelerating effects on the thyroid uptake of I131 for the female, and on the release of thyroid hormone in the blood of male rats. This diverse response against estrogen is considered to be attributable to the difference in the affinity of the thyroid to estrogen.(2) When progesterone is injected to the castrated female rats, no changes were found, and in the male, decreased thyroid uptake of I131 was found 14 days, and no obvious changes occurred 2 months after castration.(3) Androgen has no constant effects on the thyroid of the castrated both sexes.(4) By the fact that estrogen has coherent effects on the thyroid while androgen causes no change, it can be assumed that the sexual differences are chiefly attributable to estrogen.(5) The results of steroid hormones injection indicated that in the female thyroid is closely related with the gonad, while the thyroid in the male is not under this control.(6) Estrogen has an accelerating effects on the female thyroid uptake of I132 irrespective of post-operative periods, suggests the reason for the more frequent occurrence of thyroid diseases in the female.3) In order to explain the mechanism in which estrogen is the primary fractor on the sexual differences of the thyroid, estrogen was administered to the hypophysectomized female rats and its effect was investigated. Thyroid uptake of I131 showed remarkable increase in comparison with the control groups. By this fact, it can be noted that the estrogen has a direct effects on the thyroid.

Diagnostic and therapeutic uses of Iodine 131.

The authors list and explain the five properties of radioactive iodine—I131—which make this isotope most useful in the diagnosis and treatment of thyroid disease. The various types of diagnostic use of I131 are described along with the value and limitations of these methods. Indications for the therapeutic use of radioiodine are discussed.