Iodine-125 electrons from the radioisotope have been found in one study to do little cellular damage, unless the radionuclide is incorporated chemically directly into cellular DNA, which is not the case for present radiopharmaceuticals which use I-125 as the radioactive label nuclide. As with other radioisotopes of iodine, iodine-125 uptake in the body (mostly to the thyroid) can be blocked with prompt administration of stable iodine-127 in the form of an iodide or iodate salt. Potassium iodide (KI) is typically used for this purpose. Iodine-125 Iodine-125 (I) is a radioisotope of iodine which has uses in biological assays, nuclear medicine imaging
Pineal gland retina of the lateral eyes of vertebrates. In most vertebrates, exposure to light sets off a chain reaction of enzymatic events within the pineal gland that regulates circadian rhythms. In humans and other mammals, the light signals necessary to set circadian rhythms are sent from the eye through the retinohypothalamic system to the suprachiasmatic nuclei (SCN) and the pineal gland. The fossilized skulls of many extinct vertebrates have a pineal foramen (opening), which in some cases is larger than that of any living vertebrate. Although fossils seldom preserve deep-brain soft anatomy, the brain of the Russian fossil bird "Cerebavis cenomanica"