Acute exposure to space flight results in evidence of reduced lymph Transport, tissue fluid Shifts, and immune alterations in the rat gastrointestinal system.

Space flight causes a number of alterations in physiological systems, changes in the immunological status of subjects, and altered interactions of the host to environmental stimuli. We studied the effect of space flight on the lymphatic system of the gastrointestinal tract which is responsible for lipid transport and immune surveillance which includes the host interaction with the gut microbiome. We found that there were signs of tissue damage present in the space flown animals that was lacking in ground controls (epithelial damage, crypt morphological changes, etc.). Additionally, morphology of the lymphatic vessels in the tissue suggested a collapsed state at time of harvest and there was a profound change in the retention of lipid in the villi of the ileum. Contrary to our assumptions there was a reduction in tissue fluid volume likely associated with other fluid shifts described. The reduction of tissue fluid volume in the colon and ileum is a likely contributing factor to the state of the lymphatic vessels and lipid transport issues observed. There were also associated changes in the number of MHC-II+ immune cells in the colon tissue, which along with reduced lymphatic competence would favor immune dysfunction in the tissue. These findings help expand our understanding of the effects of space flight on various organ systems. It also points out potential issues that have not been closely examined and have to potential for the need of countermeasure development.

Visualization of nasolacrimal drainage system after radioiodine therapy in patients with thyroid cancer.

The objective of this study was to report three cases with an accumulation of (131)I in the nasolacrimal duct after radioiodine therapy for papillary thyroid cancer. A whole-body scan was taken 3 days after the administration of 3.7 GBq of (131)I. Single-photon emission computed tomography (SPECT)/CT images were added when the location of a focal tracer uptake was undetermined on whole-body scans. In case 1, a 62-year-old woman complained of epiphora of the left eye after nine radioiodine therapies with a cumulative dose of 31.08 GBq. The left nasolacrimal duct was visualized at her tenth treatment with (131)I. In case 2, a series of three radioiodine therapies had been given to a 73-year-old woman with a cumulative dose of 11.1 GBq. The accumulation of (131)I was noted in the left nasolacrimal duct at her fourth treatment. She complained of epiphora of the left eye. In case 3, bilateral nasolacrimal ducts were visualized at the second radioiodine therapy in a 75-year-old woman. The patient had received 3.7 GBq of (131)I at the first therapy. She did not complain of epiphora. It is possible that radiation from (131)I that is secreted in tears and/or actively accumulated in the nasolacrimal duct may induce nasolacrimal duct obstruction. (131)I in tears would be responsible for the visualization of nasolacrimal duct in the first two cases. (131)I actively accumulated in the nasolacrimal duct might have been visualized in the third case. In summary, (131)I is excreted in tears and is actively accumulated in the nasolacrimal duct. Obstruction of the lacrimal drainage system could occur after high-dose radioiodine therapy.