Authors:P. Vermaercke, F. Farina, L. Sneyers, M. Bruggeman, and J. Bouças
Several recent intercomparisons and certification exercises have shown that the determination of tin in e.g. food samples
and plastics is not straightforward. k0-Instrumental Neutron Activation Analysis (k0-INAA) offers some intrinsic quality control opportunities for the determination of the tin content in samples since several
monitoring radioisotopes are formed. In this work we will discuss the validation of the determination of tin by k0-INAA using different reference materials. The results show that only few of these radioisotopes are reliable in terms of
accuracy and that from a survey of the tin content in a range of canned foods detection limits as low as 2 mg/kg can be achieved.
Authors:L. Sneyers, L. Verheyen, P. Vermaercke, and M. Bruggeman
A recent study on trace elements in beauty products and cosmetics sold on the Asian market has shown the presence of high
levels of U, Th and rare earth elements in so called “Hormesis cosmetics.” For the purpose of comparison, some more information
about trace elements in European cosmetics would be useful. In this paper the results obtained using k0-standardised Instrumental Neutron Activation Analysis (k0-INAA) for more than 20 trace elements in 20 different beauty products collected from the European market are presented. We
found traces of Ba, As and Sb which is in breach with European legislation. For some of the other elements like Cr and Co
further speciation is needed in order to evaluate their presence in beauty products.
Authors:P. Vermaercke, L. Sneyers, M. Bruggeman, A. De Wispelaere, and F. De Corte
Several methods are in use for the determination of the thermal to epithermal neutron fluence rate ratio (f) and the deviation of the epithermal neutron spectrum from the 1/E shape parameter (α). In our former work, it was proven that the recently developed and characterized Synthetic Multi-ELement Standard (SMELS)
can be used for the fast verification of the stability of the irradiation parameters using the Au-Zr bare monitor method.
However, this latter method using SMELS had a too low precision for an accurate determination of f and α. Therefore, the Cd-ratio for multi-monitor method using SMELS was investigated for two irradiation channels. As shown the
material can also be used as a monitor for the calibration of an irradiation facility.
Authors:P. Van As, C. Careghi, V. Bruggeman, O. M. Onagbesan, S. Van der Geyten, V. M. Darras, and E. Decuypere
Pit-1 is a pituitary-specific POU-domain DNA binding factor, which binds to and trans-activates promoters of growth hormone- (GH), prolactin- (PRL) and thyroid stimulating hormone beta- (TSHβ) encoding genes. Pit-1 has been identified in several mammalian and avian species. Thyrotropin-releasing hormone (TRH) is located in the hypothalamus and it stimulates TSH, GH and PRL release from the pituitary gland. In the present study, we successfully developed a competitive RT-PCR for the detection of Pit-1 expression in the chicken pituitary, that was sensitive enough to detect picogram levels of Pit-1 mRNA. Applying this method, the effect of TRH injections on Pit-1 mRNA expression was determined in the pituitary of chick embryos and growing chicks. In both 18-day-old embryos and 10-day-old male chicks the Pit-1 mRNA expression was significantly increased following TRH injection, thereby indicating that the stimulatory effects of TRH on several pituitary hormones is mediated via its effect on Pit-1 expression. Therefore, a semi-quantitative RT-PCR method was used to detect possible changes in GH levels. TRH affected the GH mRNA levels at both developmental stages. These results, combined with the data on Pit-1 mRNA expression, indicate that Pit-1 has a role in mediating the stimulatory effects of TRH on pituitary hormones like GH.
Authors:P. Van As, K. Janssens, K. Pals, B. De Groef, O. M. Onagbesan, V. Bruggeman, V. M. Darras, C. Denef, and E. Decuypere
Pit-1 is a pituitary-specific POU-domain DNA binding factor, which binds to and trans-activates promoters of growth hormone- (GH), prolactin- (PRL) and thyroid stimulating hormone-beta- (TSHβ) encoding genes. Thyrotropin-releasing hormone (TRH) is located in the hypothalamus and stimulates TSH, GH and PRL release from the pituitary gland. In the present study, we successfully used the cell aggregate culture system for chicken pituitary cells to study the effect of TRH administration on the ggPit-1* (chicken Pit-1), GH and TSHβ mRNA expression in vitro. In pituitary cell aggregates of 11-day-old male broiler chicks the ggPit-1* mRNA expression was significantly increased following TRH administration, indicating that the stimulatory effects of TRH on several pituitary hormones are mediated via its effect on the ggPit-1* gene expression. Therefore, a semi-quantitative RT-PCR method was used to detect possible changes in GH and TSHβ mRNA levels. TRH affected both the GH and TSHβ mRNA levels. The results of this in vitro study reveal that ggPit-1* has a role in mediating the stimulatory effects of TRH on pituitary hormones like GH and TSHβ in the chicken pituitary.