RESUMO
Subcritical calvarial defects heal spontaneously and optical methods can study the healing without mechanically perturbing the bone. In this study, 1mm defects were created on the skulls (in vivo) of Sprague-Dawley rats (n = 14). After 7 (n = 7) and 14 days (n = 7) of healing, the subjects were sacrificed and additional defects were similarly created (control). Raman spectroscopy (785nm) was performed at the two time points and defect types. Spectra were quantified by the mineral/matrix ratio, carbonate/phosphate ratio and crystallinity. Mineral/matrix of in vivo defects is lower than that of controls by ~34% after 7 days and ~21% after 14 days. Carbonate/phosphate is 8% and 5% higher while crystallinity is 7% and 3% lower, respectively. Optical profiling shows that the surface roughness increases 1.2% from controls to in vivo after 7 days, then decreases 13% after 14 days. Overall, the results show maturation of mineral crystals during healing and agree with microscopic assessment.
RESUMO
Lithium-based medications are used successfully to treat many mental disorders, including bipolar disorder and Alzheimer's disease. However, the therapeutic mechanisms are not well characterized due to limitations in detecting lithium in organs and cells. This limits the ability to improve lithium-based treatments. To address this need, laser-induced breakdown spectroscopy (LIBS) is developed for the rapid and in situ detection of lithium in biological tissues. Pronounced lithium emissions are observed at 670.7nm from the rat thyroid, salivary, and mammary glands when lithium is administered orally. Calcium, carbon, magnesium, sodium, potassium, and iodine emissions are also observed. The lithium emission intensity is positively correlated with tissue lithium concentration, which is ~1ppm. The limit of detection for lithium is determined to be ~0.1ppm. Thyroid lithium intensity increases while iodine intensity decreases. The reduced intrathyroidal iodine following treatment likely impairs hormone production. Further, the presence of lithium in the salivary and mammary glands makes these glands the likely conduits for lithium to enter the saliva and breast milk, respectively. LIBS is well suited for characterizing the distribution of lithium, and other elements, across the body. This optical method can potentially be adapted for use in vivo and in humans.
RESUMO
The thyroid is an important hormone regulation organ. Laser induced breakdown spectroscopy (LIBS) is developed to assess iodine and other essential elements in the thyroid (of rats). Subjects are administered 0.05% iodine water for 0, 6, and 12 days before the thyroid is extracted. Pronounced iodine, sodium, calcium, and potassium emissions are observed at approximately 746, 589, 395/422, and 766/770 nm, respectively. Iodine emission is surprisingly highest in 0 day subjects, lowest after 6 days, and recovers by 12 days. This follows the Wolff-Chaikoff effect as ingestion of excess iodine reduces thyroid iodine and iodine is essential for hormone production. LIBS is a promising method for trace elemental analysis of the thyroid.
RESUMO
We report a novel Raman spectroscopy method for in situ cellular level analysis of the thyroid. Thyroids are harvested from control and lithium treated mice. Lithium is used to treat bipolar disorder, but affects thyroid function. Raman spectra are acquired with a confocal setup (514 nm laser, 20 µm spot) focused on a follicular lumen. Raman peaks are observed at 1440, 1656, and 1746 cm-1, corresponding to tyrosine, an important amino acid for protein synthesis. Peaks are also observed at 563, 1087, 1265 and 1301 cm-1. With lithium, the tyrosine peaks increase, indicating tyrosine buildup. Raman spectroscopy can study the impact of many exogenous treatments on thyroid biochemistry.
