Daily urine iodine excretion while consuming a low-iodine diet in preparation for radioactive iodine therapy in a high iodine intake area.

OBJECTIVE: Recommended durations of low-iodine diet (LID) in preparation for radioactive iodine therapy (RAIT) vary among major guidelines and are important for patients in areas where iodine intake is high. The aim of this study was to investigate daily changes in urine iodine excretion after starting a LID. DESIGN: The daily iodine/creatinine (I/Cr) ratios and simple iodine concentration (simple I) of morning spot urine from 19 patients with differentiated thyroid carcinoma were measured for 2 weeks from the start of LID for RAIT preparation. We set the cut-off of I/Cr and simple I for poor LID preparation at >66·2 µg/gCr and >150 µg/l, respectively. The day when daily I/Cr or simple I became equal to or below the cut-off both by 95% CI and 90th percentile was defined as the end-point for the appropriate duration of LID for RAIT. RESULTS: On day 6 of LID, the I/Cr ratio decreased below the cut-off (≤66·2 µg/gCr) both by 95% CI (0-60·8) and by 90th percentile (51·9). Simple I reached the cut-off (≤150 µg/l) on day 3 by both parameters (95%CI: 2·3-90·5; 90th percentile: 126·5). The morning spot-urine I/Cr and simple I on day 7 and day 14 were significantly lower than on day 0 (P < 0·05). CONCLUSIONS: One week of a strict LID is enough to decrease the level of urine iodine excretion in preparation for RAIT even in high iodine intake areas. These results provide essential data for future outcome studies regarding LID preparation for RAIT.

A case of resistance to thyroid hormone with thyroid cancer.

Resistance to thyroid hormone (RTH) is an autosomal dominant hereditary disorder that is difficult to diagnose because of its rarity and variable clinical features. The magnitude of RTH is caused by mutations in the thyroid hormone receptor beta (TR beta) gene. We recently treated a 38-yr-old woman with RTH who had incidental papillary thyroid carcinoma. She presented with goiter and displayed elevated thyroid hormone levels with an unsuppressed TSH. She was determined to harbor a missense mutation of M310T in exon 9 of the TR beta gene, and diagnosed with generalized RTH. This mutation has not yet been reported in Korea. RTH is very rare and easily overlooked, but should be considered in patients who present with goiter and elevated thyroid hormone levels with an unsuppressed TSH. The association between thyroid cancer and RTH needs further study.

Trophic molecules derived from human mesenchymal stem cells enhance survival, function, and angiogenesis of isolated islets after transplantation.

BACKGROUND: Mesenchymal stem cells (MSCs), also known as multipotent progenitor cells, release several factors that support cell survival and enhance wound healing. We hypothesized that MSC-secreted molecules would induce a trophic effect in pancreatic islet culture conditions. METHODS: Pancreatic islets were co-cultured with MSCs, and ADP/ATP ratios, glucose stimulated insulin secretion (GSIS), and DNA fragmentation were evaluated to measure islet quality and viability in vitro. The induction of signal molecules related to the control of survival, function, and angiogenesis was also analyzed. Cell quality assays, DNA fragmentation assays, and islet transplantation into streptozotocin-induced diabetic mice were performed using MSC-conditioned medium (CM)-cultured islets. Furthermore, we identified soluble molecules within MSC-CM. RESULTS: Islets co-cultured with MSCs demonstrated lower ADP/ATP ratios, and higher GSIS indexes and viability. Furthermore, co-cultured islets revealed higher levels of anti-apoptotic signal molecules (X-linked inhibitor of apoptosis protein, Bcl-xL, Bcl-2, and heat shock protein-32) and demonstrated increased vascular endothelial growth factor receptor 2 and Tie-2 mRNA expression and increased levels of phosphorylated Tie-2 and focal adhesion kinase protein. Islets cultured in MSC-CM demonstrated lower ADP/ATP ratios, less apoptosis, and a higher GSIS indexes. Diabetic mice that received islet transplants (200 islet equivalent) cultured in MSC-CM for 48 hr demonstrated significantly lower blood glucose levels and enhanced blood vessel formation. In addition, interleukin-6, interleukin-8, vascular endothelial growth factor-A, hepatocyte growth factor, and transforming growth factor-beta were detected at significant levels in MSC-CM. CONCLUSIONS: These results suggest that the trophic factors secreted by human MSCs enhance islet survival and function after transplantation.

Overtly manifested diabetes mellitus after resection of insulinoma.

Insulinoma is the most common cause of endogenous hyperinsulinemic hypoglycemia in adults. However, the coincidence of insulinoma and diabetes is extremely uncommon. We describe a rare, but very interesting case of diabetes mellitus which was masked by insulinoma and was overtly manifest after the removal of the insulinoma.