Journal of Thyroid Research最新文献

[This corrects the article DOI: 10.4061/2011/678357.].

Context. Population studies of the distribution of T4/TSH set points suggest a more complex inverse relationship between T4 and TSH than that suggested by physiological studies. The reasons for the similarities and differences between the curves describing these relationships are unresolved. Methods. We subjected the curve, derived from empiric data, describing the TSH suppression response to T4, and the more mathematically derived curve describing the T4 response to TSH, to the different possible models of population variation. The implied consequences of these in terms of generating a population distribution of T4/TSH equilibrium points (a "population curve") were generated and compared to the empiric population curve. The physiological responses to primary hypothyroidism and hyperthyroidism were incorporated into the analysis. Conclusions. Though the population curve shows a similarly inverse relationship, it is describing a different relationship than the curve describing the suppression of TSH by T4. The population curve is consistent with the physiological studies of the TSH response to T4 and implies a greater interindividual variation in the positive thyroid T4 response to TSH than in the central inhibitory TSH response to T4. The population curve in the dysthyroid states is consistent with known physiological responses to these states.

Exosomes are 30-100 nm, membrane-bound vesicles containing specific cellular proteins, mRNAs, and microRNAs that take part in intercellular communication between cells. A possible role for exosomes in thyroid function has not been fully explored. In the present study, FRTL-5 rat thyroid cells were grown to confluence and received medium containing either thyroid stimulating hormone (TSH), exogenous bovine thyroglobulin (bTg), or neither additive for 24 or 48 hours followed by collection of spent medium and ultracentrifugation to isolate small vesicles. Transmission electron microscopy and Western blotting for CD9 indicated the presence of exosomes. Western blotting of exosome extract using a monoclonal anti-Tg antibody revealed a Tg-positive band at ~330 kDa (the expected size of monomeric Tg) with a higher density in TSH-treated cells compared to that in untreated cells. These results are the first to show that normal thyroid cells in culture produce exosomes containing undegraded Tg.

Background. Regional lymph node recurrence (RLNR) is common in patients with thyroid cancer but clinicopathological predictors are unclear. We aimed to clarify these predictors and identify patients who would benefit from prophylactic lymph node dissection the most. Method. 343 patients with different types of thyroid cancer were analyzed retrospectively. All patients underwent total thyroidectomy between 2007 and 2013. Results. The median ± interquartile range of patients' age was 40 ± 25 years. 245 (71.4%) patients were female. Regarding the risk of regional lymph node recurrence, we found that male gender, age ≥45 years, non-PTC (i.e., medullary, follicular, and anaplastic types) histopathology, T3 (i.e., tumor size >4 cm in the greatest dimension limited to the thyroid or any tumor with minimal extrathyroid extension), stage IVa, and isolated cervical lymphadenopathy as initial manifestation (ICL) are significant risk factors. T3 (p < 0.001; odds ratio = 156.41, 95% CI [55.72-439.1]) and ICL (p < 0.001; odds ratio = 77.79, 95% CI [31.55-191.81]) were the strongest predictors of regional lymph node recurrence. Conclusion. We found easily achievable risk factors for RLNR in thyroid cancers patients. We suggested that patients with specific clinicopathological features like male gender, age ≥45 years, larger tumor size, and extrathyroidal extension be considered as prophylactic lymphadenectomy candidates.

According to the epidemiological studies, about 4.4% of American general elderly population has a pronounced hypothyroidism and relies on thyroid hormone supplements daily. The prevalence of hypothyroidism in our patients with pancreatic cancer was much higher, 14.1%. A retrospective analysis was performed on patients who underwent pancreaticoduodenectomy (Whipple procedure) or distal pancreatectomy and splenectomy (DPS) at Thomas Jefferson University Hospital, Philadelphia, from 2005 to 2012. The diagnosis of hypothyroidism was correlated with clinicopathologic parameters including tumor stage, grade, and survival. To further understand how thyroid hormone affects pancreatic cancer behavior, functional studies including wound-induced cell migration, proliferation, and invasion were performed on pancreatic cancer cell lines, MiaPaCa-2 and AsPC-1. We found that hypothyroid patients taking exogenous thyroid hormone were more than three times likely to have perineural invasion, and about twice as likely to have higher T stage, nodal spread, and overall poorer prognostic stage (P < 0.05). Pancreatic cancer cell line studies demonstrated that exogenous thyroid hormone treatment increased cell proliferation, migration, and invasion (P < 0.05). We conclude that exogenous thyroid hormone may contribute to the progression of pancreatic cancer.