Age-Related-Changes-of-Trace-Element-Contents-in-Intact-Thyroid-of-Females-Investigated-by-Neutron-Activation-Analysis

Abstract

IntroductionThe endocrine organs, including the thyroid gland, undergo important functional changes during aging and a prevalence of thyroid dysfunction is higher in the elderly as compared to the younger population [1,2]. Advancing age is known to influence the formation of adenomatous goiter and thyroid cancer [3]. The prevalence of thyroid nodules is increased in the elderly, reaching a frequency of nearly 50% by the age of 65 [4]. Both prevalence and aggressiveness of thyroid cancer increase with age [2]. Women are affected by thyroid nodule and cancer two to five times more often than men [2][3][4][5].Aging is a complex process involving biochemical and morphologic changes in single cells, in organs and in the whole organism. One of the most generally accepted explanations of how aging occurs at the molecular level is the oxidative stress hypothesis [6]. Reactive Oxygen Species (ROS) are widely considered to be a causal factor not only in aging but in a number of pathological conditions, including carcinogenesis. Aging, considered as an impairment of body functions over time, caused by the accumulation of molecular damage in DNA, proteins and lipids, is also characterized by an increase in intracellular oxidative stress due to the progressive decrease of the intracellular ROS scavenging [7]. Oxidative damage to cellular macromolecules which induce cancer can also arise through overproduction of ROS and faulty antioxidant and/or DNA repair mechanisms [8]. Overproduction of ROS is associated with inflammation, radiation and some other factors, including overload of some trace elements, in both blood and certain tissues, or deficiency of other trace elements with antioxidant properties [9][10][11][12][13][14][15]. Studies have shown that the imbalance in the composition of trace elements may cause different types of pathology. The importance of appropriate levels of many trace elements is indisputable, due to their beneficial roles when in specific concentration ranges, while on the other hand they can cause toxic effects with excessively high or low concentrations [12].In our previous studies [16][17][18][19][20][21][22][23][24] the high mass fraction of Iodine (I) and some other trace element were observed in intact human thyroid gland when compared with their levels in non-thyroid soft tissues of the human body. However, some questions about the age-dependence of trace element mass fraction in thyroid of adult, and particularly, elderly females still remain unanswered. One valuable way to elucidate the situation is to compare the mass fractions of trace elements in young adult (the control group) with those in older adult and geriatric thyroid. The findings of the excess or deficiency of trace element contents in thyroid and the perturbations of their relative proportions in glands of adult and elderly females, may give an indication of their role in a higher prevalence of thyroid dysfunction in the elderly. The reliable data on trace element mass fractions in normal geriatric thyroid is apparently extremel...

Possible Role of Inadequate Quantities of Intra-Thyroidal Bromine, Calcium and Magnesium in the Etiology of Female Subclinical Hypothyroidism

“…The ratios of means and the difference between mean values of Br, Ca, Cl, I, K, Mg, Mn, and Na mass fractions in normal thyroid of females and males are presented in Table 4. Because, in our previous studies age-dependents of many ChE in thyroid gland was found [51][52][53][54], the comparison between ChE contents in thyroid of females and males separately in age group 1 and in age group 2 was also performed (Tables 5 & 6). The data of inter-correlation calculations (values of r -coefficient of correlation) including all ChE identified by us in thyroid of females and males separately are presented in Table 7.…”

Determination of twenty chemical element contents in normal and goitrous thyroid using X-ray fluorescent and neutron activation analysis

“…In our previous studies, we found a significant age-related increase of Br content in human thyroid [25][26][27][28]31,32]. Therefore, a goitrogenic and, probably, carcinogenic effect of excessive Br levels in the thyroid of old females was assumed.…”

“…The content of Br, Ca, Cl, I, K, Mg, Mn, and Na were determined by INAA-SLR using a horizontal channel equipped with the pneumatic rabbit system of the WWR-c research nuclear reactor (Branch of Karpov Institute, Obninsk). Details of used neutron flux, nuclear reactions, radionuclides, gamma-energies, and spectrometric unit were presented in our earlier publications concerning the INAA-SLR of ChE contents in human thyroid, scalp hair, and prostate [27,28,[51][52][53] In a few days after INAA-SLR all thyroid samples were repacked separately in a high-purity aluminum foil washed with rectified alcohol beforehand and placed in a nitric acid-washed quartz ampoule and used for INAA-LLR. A vertical channel of the WWR-c research nuclear reactor (Branch of Karpov Institute, Obninsk).was applied to determine the content of Ag, Co, Cr, Fe, Hg, Rb, Sb, Sc, Se, and Zn by INAA-LLR.…”

“…A vertical channel of the WWR-c research nuclear reactor (Branch of Karpov Institute, Obninsk).was applied to determine the content of Ag, Co, Cr, Fe, Hg, Rb, Sb, Sc, Se, and Zn by INAA-LLR. Details of used neutron flux, nuclear reactions, radionuclides, gamma-energies, and spectrometric unit were presented in our earlier publications concerning the INAA-LLR of ChE contents in human thyroid, scalp hair, and prostate [29,30,51,54].…”

“…Level of I in the normal thyroid was investigated in relation to age, gender and some non-thyroidal diseases [23,24]. After that, variations of ChE content with age in the thyroid of males and females were studied and age-and gender-dependence of some ChE was observed [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Furthermore, a significant difference between some ChE contents in normal and cancerous thyroid was demonstrated [42][43][44][45][46][47].…”