Gender-specific regulation of response to thyroid hormone in aging

<p>Abstract</p> <p>Background</p> <p>Similar to other systems, the endocrine system is affected by aging. Thyroid hormone, the action of which is affected by many factors, has been shown to be associated with longevity. The most useful marker for the assessment of thyroid hormone action is TSH level. Although age and gender are believed to modify the pituitary set point or response to free thyroid hormone concentration, the precise age- and gender-dependent responses to thyroid hormone have yet to be reported.</p> <p>Methods</p> <p>We analyzed the results of 3564 thyroid function tests obtained from patients who received medication at both out- and inpatient clinics of Shinshu University Hospital. Subjects were from among those with thyroid function test results in the normal or mildly abnormal range. Based on a log-linear relationship between the concentrations of FHs and TSH, we established the putative resistance index to assess the relation between serum FH and TSH levels.</p> <p>Results</p> <p>Free thyroid hormone and TSH concentration showed an inverse log-linear relation. In males, there was a negative relationship between the free T3 resistance index and age. In females, although there were no relationships between age and FHs, the indices were positively related to age.</p> <p>Conclusions</p> <p>These findings indicated that there is a gender-specific response to thyroid hormone with aging. Although the TSH level is a useful marker for the assessment of peripheral thyroid hormone action, the values should be interpreted carefully, especially with regard to age- and gender-related differences.</p

Three Dimensional Motion Control System of Ferromagnetic Particles for Magnetically Targeted Drug Delivery Systems

The development of a 3-dimensional (3-D) navigation system of ferromagnetic particles in a flow system was performed. In order to improve the practice of using externally-applied magnetic fields for targeting the magnetic particles to a circumscribed body region, we tested the feasibility of a novel 3-D navigation system, made by applying a strong external (magnetic) field through a GdBaCuO bulk superconductor. A 3-D theoretical model is proposed and used in order to evaluate the efficiency of the navigation/retention of magnetic particles in the flow system. Furthermore, an experimental model system was made and the efficiency of a prototype system was examined. Comparisons of experimental and the corresponding calculation results were made to examine the theoretical model system