[Evaluation of thyroid function in a group of over-eighty year-old people]. / Valutazione della funzionalità tiroidea in un gruppo di ultraottantenni.

AIM: A number of studies has shown that during aging thyroid presents some structural changes, whilst no data agree about secretory activity. The aim of the present study was to evaluate thyroid function in a group of healthy over-80 years old people vs a group of young subjects. METHODS: This study was performed on 48 old people, 33 women (68.75%) and 15 men (31.25%), mean age 86.38+/-5.20 years old and 43 young subjects, mean age 33.35+/-3.75 years old; all of them were euthyroid and were not affected with any acute or chronic diseases and did not take any drugs which could interfere with thyroid function. A blood sample was taken from each patient, for dosing TT3, TT4, FT3, FT4, TSH, TgAb, TPOAb. RESULTS: The results of the present study show low serum levels of TT3 in healthy over-80 year old people compared to young people, even if serum levels of TT4, FT3, FT4, TSH have no significant changes. CONCLUSIONS: Functional reduction in thyroid activity during aging has not to be considered responsible for senile involution; it is more appropriate to define it as the expression of a metabolic slow down in the elderly.

Cycle anatomy and variability in the storm-dominated type cincinnatian (Upper Ordovician): coming to grips with cycle delineation and genesis.

Although parasequence and sequence are scale-independent terms, they are frequently applied only to specific scales of cycles. For example, meter-scale cycles are commonly assumed to be parasequences or PACs. In the Upper Ordovician Kope and Fairview Formations of northern Kentucky, we examined a succession of 50 meter-scale cycles that have been variously interpreted as deepening-upward, shallowing-upward, or showing no relationship with water depth. Our analysis shows that these cycles, characterized by shifts in storm-bed proximality, are highly variable in their thickness and internal construction. Most cycles are best considered high-frequency sequences, because deepening-upward intervals are common, and many cycles contain evidence of abrupt basinward shifts in facies as expected at sequence boundaries. A minority fit the parasequence model of shallowing-upward cycles bounded by flooding surfaces. Larger, 20 m scale cycles are defined by systematic thickening and thinning trends of meter-scale cycles. However, meter-scale cycles do not display any systematic trends in cycle anatomy as a function of position within the 20 m cycles or position within the Kope and Fairview Formations. The high cycle variability and the lack of systematic stratigraphic organization with respect to longer-term cyclicity reflect either the irregularity of relative sea-level changes, the poor recording of sea-level changes in this deep-water setting, or the generation of these cycles by climate-induced cyclicity in storm intensity. These three mechanisms would generate similar patterns at the outcrop scale, so it is not possible at the present to distinguish between them.