Retinol Levels in Hashimoto's Thyroiditis

Hashimoto’s thyroiditis (HT) is one of the most common autoimmune diseases in the United States. Previous studies have proven that HT patients often have low vitamin D levels and benefit from vitamin D supplementation to help manage their autoimmune disease. Research is currently underway to investigate vitamin A’s benefits in the management of autoimmune diseases. Both of these vitamins have immune-modulating properties, and both affect thyroid function. This dissertation aims to establish whether HT patients had lower retinol (vitamin A) levels than participants that did not have HT. Data regarding retinol levels and thyroid function markers were gathered from a database of results from a small study conducted at Health Matters Clinic, in Northeast Arkansas. The study participants were sorted into two groups: HT and non-HT, and then 26 participants were randomly selected for each group. The HT group had participants that were positive for either or both thyroperoxidase and thyroglobulin antibodies, and that were not on thyroid medications such as levothyroxine. The non-HT group had participants that did not have thyroid autoantibodies, and did not have any other known autoimmune disease and had normal Thyroid Stimulating Hormone (TSH) levels. An independent sample t-test for differences in retinol levels was performed, as well as Pearson’s correlation for retinol and TSH and retinol and the anti-thyroid antibodies. The results revealed no statistical differences in retinol levels between the groups and no correlation between retinol and the level of thyroid antibodies. Retinol’s tight homeostatic control, which maintains steady serum levels regardless of liver reserve status, can explain the lack of statistical difference in retinol levels between the groups. A positive correlation was found between retinol and TSH levels (high TSH with high retinol), which may indicate some novel mechanism of retinol’s effect on the thyroid or retinol’s involvement in the etiology of HT, therefore, needs to be validated with more data. In conclusion, serum retinol levels do not appear to correlate with HT; in particular, serum retinol levels appear not to be decreased in patients with HT. At the same time, our data seem to indicate some involvement of retinol, or its signaling pathway, in thyroid disorders

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Detection of ultra-weak magnetic fields in Am stars: beta UMa and theta Leo

An extremely weak circularly polarized signature was recently discovered in spectral lines of the chemically peculiar Am star Sirius A. A weak surface magnetic field was proposed to account for the observed polarized signal, but the shape of the phase-averaged signature, dominated by a prominent positive lobe, is not expected in the standard theory of the Zeeman effect. We aim at verifying the presence of weak circularly polarized signatures in two other bright Am stars, beta UMa and theta Leo, and investigating the physical origin of Sirius-like polarized signals further. We present here a set of deep spectropolarimetric observations of beta UMa and theta Leo, observed with the NARVAL spectropolarimeter. We analyzed all spectra with the Least Squares Deconvolution multiline procedure. To improve the signal-to-noise ratio and detect extremely weak signatures in Stokes V profiles, we co-added all available spectra of each star (around 150 observations each time). Finally, we ran several tests to evaluate whether the detected signatures are consistent with the behavior expected from the Zeeman effect. The line profiles of the two stars display circularly polarized signatures similar in shape and amplitude to the observations previously gathered for Sirius A. Our series of tests brings further evidence of a magnetic origin of the recorded signal. These new detections suggest that very weak magnetic fields may well be present in the photospheres of a significant fraction of intermediate-mass stars. The strongly asymmetric Zeeman signatures measured so far in Am stars (featuring a dominant single-sign lobe) are not expected in the standard theory of the Zeeman effect and may be linked to sharp vertical gradients in photospheric velocities and magnetic field strengths