Radioiodine is used to treat thyroid cancer and hyperthyroidism. In order to reduce radiation hazard to the patient and to people in contact with the patient it would be desirable to obtain the same therapeutic effect with lower activities of the radioisotope. This could be achieved by the simultaneous administration of a compound that increases tissue radiosensitivity. In this study we analyzed the use of nicotinamide (NA) as a radiosensitizer to radioiodine, to increase 131I efficacy. NA administered during 30 days to Wistar rats failed to alter thyroid weight. The influence of NA on radiothyroidectomy induced by increasing doses of 131I was examined in otherwise nontreated rats. NA produced a significant increase in the ablation caused by radioiodine. Goiter was then induced by the administration of methylmercaptoimidazol (MMI) to rats, followed by the treatment with radioiodine with and without simultaneous administration of NA. Thyroid weight per 100 g of body weight ratio was not changed by NA alone; 131I administration caused a 25% decrease in goiter size, while 131I plus NA produced a reduction of the ratio of 46% (p < 0.01 vs. NA). No changes were observed in adenosine diphosphate (ADP)-ribosilation of thyroid nuclear protein in NA-treated rats. Thyroid blood flow (determined by 86Rb uptake) was increased by 84% by NA. In conclusion, nicotinamide has a significant radiosensitizing effect to 131I both in normal and goitrous rats. This action is because of an increase in thyroid blood flow, which probably enhances tissue oxgenation.

Download full-text PDF

Source
http://dx.doi.org/10.1089/105072501753271671DOI Listing

Publication Analysis

Top Keywords

normal goitrous
8
simultaneous administration
8
thyroid weight
8
thyroid blood
8
blood flow
8
thyroid
7
131i
5
rats
5
influence nicotinamide
4
nicotinamide radiosensitivity
4

Similar Publications

Background: Ectopic thyroid tissue is a developmental disorder and is extraordinarily rare to occur in the central airway. To our knowledge, nearly few reports of primary ectopic thyroid carcinoma in the central airway with a normal eutopic thyroid gland have been published to date. This is the second case about malignant central airway obstruction caused by primary ectopic thyroid carcinoma.

View Article and Find Full Text PDF

Objective: Guidelines on congenital hypothyroidism (CH) recommend that genetic testing should aim to improve diagnosis, treatment or prognosis, but it is unclear which patients would benefit most from the genetic investigation. We aimed to investigate the genetic etiology of transient CH (TCH) and permanent CH (PCH) in a well-characterized cohort, and thereby evaluate the impact of genetic testing on the management and prognosis of children with CH.

Methods: A total of 48 CH patients with normal, goitrous (n 5) or hypoplastic thyroid (n 5) were studied by high-throughput sequencing using a custom-designed 23-gene panel.

View Article and Find Full Text PDF
Article Synopsis
  • A study was conducted on 103 adult patients with congenital hypothyroidism (CH) diagnosed through newborn screening to evaluate their thyroid morphology and function, focusing on those born after 1979.
  • The patients were categorized into Goiter, Normal gland, and Dysgenesis groups; results indicated a significantly low serum free triiodothyronine/free thyroxine ratio in the Dysgenesis group and a higher incidence of thyroid nodules in female CH patients compared to non-CH women.
  • Genetic defects linked to goitrous congenital hypothyroidism were found in 89% of the Goiter group, suggesting that patients with dyshormonogenesis should have regular thyroid ultrasounds due to their increased risk for thyroid nodules
View Article and Find Full Text PDF

Background: The presence of ectopic thyroid tissue is a developmental disorder that affects about one per 100,000-300,000 people. It is extraordinarily rare for ectopic thyroid to be out of the lines of its descent. This case is the first to report a cancerous ectopic thyroid in the mandibular bone with a goitrous orthotopic thyroid gland.

View Article and Find Full Text PDF

SLC26A4 is a known iodide transporter, and is localized at the apical membrane of thyrocytes. Previously, we reported that SLC26A7 is also involved in iodide transport and that Slc26a7 is a novel causative gene for congenital hypothyroidism. However, its detailed role in vivo remains to be elucidated.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!