Minor and potentially toxic trace elements in milk and blood serum of dairy donkeys

The aim of this trial was to study the concentration of Ti, V, As, Rb, Sr, Mo, Cd, Cs, and Pb in donkey milk and blood serum. One hundred twelve individual milk and blood serum samples were collected from 16 lactating donkeys (Martina-Franca-derived population; 6 to 12 yr old; 3 to 7 parities; average live weight 205.4kg; 32 to 58 d after foaling at the beginning of the trial) during a 3-mo-long experiment. The samples were analyzed for the aforementioned elements by inductively coupled plasma-mass spectrometry. Feedstuff and drinking water were also analyzed for the investigated elements. Data were processed by ANOVA for repeated measures. Average milk concentrations (±SD) of Ti, Rb, Sr, Mo, Cs, and Pb were 77.3 (±7.7), 339.1 (±82.1), 881.7 (±270.4), 4.5 (±1.6), 0.49 (±0.09), and 3.2 (±2.7) μg/L, respectively. More than 80% of samples were below the limit of detection for V, As, and Cd in milk and for Cd, and Pb in blood serum. The lower bound calculated for milk V, As, and Cd was 0.03μg/L for the 3 elements, the upper bound was calculated at 0.23, 0.10, and 0.31μg/L and the maximum value was observed at 0.54, 0.15, and 0.51μg/L, respectively. The average milk concentrations of Ti, Rb, Sr, Mo, and Cs were 600, 458, 346, 16, and 294%, respectively, than those of blood serum. Yet, Cs concentrations were in the same order of magnitude in milk and serum. Moderate to strong positive and significant correlation coefficients were observed between milk and blood serum concentrations for Ti, Rb, Sr, and Cs. The effect of the stage of lactation was significant for all the investigated elements in milk and blood serum, but most of the elements showed only small changes or inconsistent trends, and only the concentrations of Rb and Sr showed decreasing trends both in milk and blood serum. The relationship between milk and blood serum element concentrations indicates that the mammary gland plays a role in determining the milk concentrations of Mo, Ti, Rb, Sr, Mo, and Cs. In the current experimental conditions, in agreement with the low levels in drinking water and feedstuff, donkey milk concentration of potentially toxic elements was very low and did not raise health concerns for human consumption

Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

The effects of reproduction and maternal investment (i.e., milk transfer) on trace element levels remain poorly understood in marine mammals. We examined the blood dynamics of mercury (Hg) and selenium (Se) during lactation in the northern elephant seal (Mirounga angustirostris), a top predator from the North Pacific Ocean. Total Hg and Se levels were measured in whole blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. Both Hg and Se were transferred to offspring through the milk. Results suggested that the maternal transfer of Se was prominent during lactation, whereas the Hg transfer was larger during gestation. The lactation period affected Hg and Se levels in the blood of elephant seal mothers and pups. Physiological processes and their relationship to body condition should be considered carefully when interpreting trace element levels in the framework of biomonitoring.Peer reviewe

Ontogenesis and migration of metallothionein I/II-containing glial cells in the human telencephalon during the second trimester

Metallothioneins (MT) belong to a widespread family of proteins characterized by a high metal content (mainly Cu(2+) and Zn(2+)) and by the presence of cysteine residues. The expression of metallothionein I-II (MT I/II), glial fibrillary acid protein (GFAP), and vimentin was examined in a series of 16 developing human brains of the second trimester. The brains of a stillborn/newborn individual and two postnatal individuals were studied for comparison. MT I/II-containing cells became consistently and clearly visible only from gestational week 21 onwards. On the other hand, several densely packed GFAP- and vimentin-containing elements were evident in the neuroepithelium at several periventricular locations and in the subventricular zone of all fetuses of the series. GFAP- and vimentin-containing elements also entered the intermediate plate, but only a few elements were evident in the outer layers of the maturing cortex. The relatively late onset of MT I/II expression and their distribution are discussed in relation to the uptake of trace elements during the last trimester of pregnancy, and the role of astrocytes in neuronal guidance and maturation of cortical circuits

Expression of aromatase P450(AROM) in the human fetal and earlypostnatal cerebral cortex

Aromatase (P450AROM), the enzyme responsible for the conversion of testosterone (T) into 17-β estradiol (E2), plays a crucial role in the sexual differentiation of specific hypothalamic nuclei. Moreover, recent findings indicate that local E2 synthesis has an impact on other brain areas including hippocampus, temporal cortex and cerebellum, and may thus influence also cognitive functions. Numerous studies have described the expression and the distribution of P450AROM throughout ontogenesis and postnatal development of the central nervous system in several mammals, but data referring to humans are scarce. In the adult human brain, P450 AROM has been detected in the hypothalamus, limbic areas, and in the basal forebrain, and described in glial cells of the cerebral cortex and hippocampus. In this study we report the expression, distribution and cellular localization of P450AROM in the human fetal and early postnatal cerebral cortex. In our series of fetal brains of the second trimester, P450AROM expression appeared at gestational week (GW) 17 and resulted limited to groups of cells localized close to the growing neuroepithelium in the ventricular and subventricular zones. At GWs 20-24, scattered P450 AROM immunoreactive (-ir) neural cells were identified in the intermediate plate and subplate, and in the parietal cortical plate. In perinatal and early postnatal individuals the quantity of P450AROM-ir elements increased, and revealed the morphology typical of glial cells. Double labeling immunostaining with anti-GFAP and anti-P450AROM antisera, and subsequent confocal analysis, confirmed this observation. Our data show that the expression of P450AROM in the fetal cortex starts approx at the end of the fourth gestational month, but increases steadily only in the last trimester or in the early postnatal period. This temporal trend may suggest that P450AROM could act as a differentiation-promoting factor, based on timing of the steroid actions. © 2012 Elsevier B.V. All rights reserved