Composition, Release, and Transformation of Earthworm Tissue-Bound Residues of Tetrabromobisphenol A in Soil

Earthworms accumulate organic pollutants to form earthworm tissue-bound residues (EBRs); however, the composition and fate of EBRs in soil remain largely unknown. Here, we investigated the fate of tetrabromobisphenol A (TBBPA)-derived EBRs in soil for 250 days using a 14C-radioactive isotope tracer and the geophagous earthworm Metaphire guillelmi. The EBRs of TBBPA in soil were rapidly transformed into nonextractable residues (NERs), mainly in the form of sequestered and ester-linked residues. After 250 days of incubation, 4.9% of the initially applied EBRs were mineralized and 69.3% were released to extractable residues containing TBBPA and its transformation products (TPs, generated mainly via debromination, O-methylation, and skeletal cleavage). Soil microbial activity and autolytic enzymes of earthworms jointly contributed to the release process. In their full-life period, the earthworms overall retained 24.1% TBBPA and its TPs in soil and thus prolonged the persistence of these pollutants. Our study explored, for the first time, the composition and fate of organic pollutant-derived EBRs in soil and indicated that the decomposition of earthworms may release pollutants and cause potential environmental risks of concern, which should be included in both environmental risk assessment and soil remediation using earthworms.

Transient Leukopenia After Radioactive Iodine Treatment in Patients With Graves' Disease: A Retrospective Cohort Study

CONTEXT

Radioactive 131I (RAI) for the treatment of differentiated thyroid cancer is known to induce bone marrow suppression, which occurs approximately 1 month after treatment. However, it is unknown whether RAI therapy for Graves' disease causes bone marrow suppression.

OBJECTIVE

This study aimed to evaluate the short- and long-term effects of RAI therapy on bone marrow function in patients with Graves' disease.

METHODS

In this retrospective cohort study, we included patients with Graves' disease who received RAI therapy only once between 2003 and 2019 at Tokyo Women's Medical University. Blood cell counts at baseline were compared with counts at 1, 2, 4, 12, 24, 48, 144, and 240 weeks after RAI therapy. Moreover, changes in white blood cell (WBC) count and leukopenia at 1 week after RAI treatment were compared by baseline patient characteristics.

RESULTS

We enrolled 48 patients. Leukopenia was observed in 6 patients at 1 week after RAI treatment, and the overall WBC count significantly decreased (P < 0.001) 1 week after the therapy; however, the values were not significantly lower after 2 weeks. Neither red blood cell nor platelet count were significantly altered. Moreover, independent of other factors, the neutrophil count at the baseline was significantly negatively associated with changes in WBC count or the occurrence of leukopenia 1 week after the RAI treatment.

CONCLUSION

These data showed that RAI treatment induced transient reduction in the WBC count 1 week after treatment, although WBC levels were subsequently restored.

Nutritional impact of elevated calcium transport activity in carrots

Nutrition recommendations worldwide emphasize ingestion of plant-based diets rather than diets that rely primarily on animal products. However, this plant-based diet could limit the intake of essential nutrients such as calcium. Osteoporosis is one of the world's most prevalent nutritional disorders, and inadequate dietary calcium is a known contributor to the pathophysiology of this condition. Previously, we have modified carrots to express increased levels of a plant calcium transporter (sCAX1), and these plants contain approximately 2-fold-higher calcium content in the edible portions of the carrots. However, it was unproven whether this change would increase the total amount of bioavailable calcium. In randomized trials, we labeled these modified carrots with isotopic calcium and fed them to mice and humans to assess calcium bioavailability. In mice feeding regimes (n = 120), we measured (45)Ca incorporation into bones and determined that mice required twice the serving size of control carrots to obtain the calcium found in sCAX1 carrots. We used a dual-stable isotope method with (42)Ca-labeled carrots and i.v. (46)Ca to determine the absorption of calcium from these carrots in humans. In a cross-over study of 15 male and 15 female adults, we found that when people were fed sCAX1 and control carrots, total calcium absorption per 100 g of carrots was 41% +/- 2% higher in sCAX1 carrots. Both the mice and human feeding studies demonstrate increased calcium absorption from sCAX1-expressing carrots compared with controls. These results demonstrate an alternative means of fortifying vegetables with bioavailable calcium.