Biomedical subjects

Andrea Didier

Publications and source records attributed to Andrea Didier.

4 recordsLinked to original sources

PubMed2006

Cellular prion protein in the bovine mammary gland is selectively expressed in active lactocytes.

The cellular prion protein (PrP(c)) is a highly conserved glycoprotein with a still enigmatic physiological function. It is mainly expressed in the central nervous system but accumulating data suggest that PrP(c) is also found in a broad spectrum of non-neuronal tissue. Here we investigated the cell-type-related PrP(c) expression in the bovine mammary gland by using immunohistochemistry (IHC), ELISA, Western blot, and real-time RT-PCR. Specific immunostaining of serial sections revealed that PrP(c) is selectively localized in mammary gland epithelial cells. Particularly strong expression was found at the basolateral surface of those cells showing active secretion. Results obtained by RT-PCR and ELISA complemented IHC findings. No correlation was found between the level of PrP(c) expression and other parameters such as age of the animals under study or stage of lactation.

Animals↗

PubMed2004

Elevated caspase-3 and Fas mRNA expression in jejunum of adult rats during subclinical zinc deficiency.

The programmed cell death-so-called apoptosis-is a physiological process occurring in all multicellular organisms to control cell-number homeostasis. Nevertheless, increase of apoptotic cell death in different organs can lead to pathological alterations. As zinc is a potent inhibitor of apoptosis, we investigated the influence of zinc deficiency on mRNA expression levels of caspase-3 and Fas in adult rats. For this purpose, 24 adult rats fed a Zn-deficient diet for up to 29 days were compared to seven animals in the control group. After 1, 2, 4, 7, 11, 16, 22 and 29 days of treatment three animals were sacrificed (n = 24). Total RNA extraction from thymus, liver, jejunum and colon was carried out. Samples were reverse transcribed and subjected to real-time PCR. Relative quantification of caspase-3 and Fas mRNA expression was achieved on the basis of normalisation by glycerolaldehyd-3-phosphate-dehydrogenase mRNA expression levels in all samples. In jejunum, up to day 11 the relative mRNA expression of the respective genes decreased. A significant increase in caspase-3 and Fas expression was found from day 11 of zinc deficiency onward. In contrast, mRNA expression in liver and colon remained unaffected, whereas thymus showed a slight but not significant increase in the expression of these genes. This study provides the first evidence that even moderate zinc deficiency in an adult, non-growing rat model is able to elevate mRNA expression levels of factors involved in early stages of apoptosis.

Animals↗

PubMed2004

Inhibition of real-time RT-PCR quantification due to tissue-specific contaminants.

Real-time reverse transcription-polymerase chain reaction (RT-PCR) is currently considered the most sensitive method to study low abundance gene expression. Since comparison of gene expression levels in various tissues is often the purpose of an experiment, we studied a tissue-linked effect on nucleic acid amplification. Based on the raw data generated by a LightCycler instrument, we propose a descriptive mathematical model of PCR amplification. This model allowed us to study amplification kinetics of four common housekeeping genes in total RNA samples derived from various bovine tissues. We observed that unknown tissue-specific factors can influence amplification kinetics but this affect can be ameliorated, in part, by appropriate primer selection.

Animals↗

PubMed2003

Tissue-specific expression pattern of bovine prion gene: quantification using real-time RT-PCR.

In recent studies PrP mRNA was determined mostly by in situ hybridisation or Northern Blot analysis--methods not suitable for absolute quantification of mRNA copy numbers. Herein we report on bovine prion mRNA quantification using calibrated highly sensitive externally standardized real-time RT-PCR with LightCycler instrument. Total RNA was isolated from nine different regions of the CNS and seven peripheral organs. PrP(c) mRNA copy numbers could be determined in all tissues under study. In approval with prior studies high mRNA level was found in Neocortex and Cerebellum. Lymphatic organs showed at least as high expression levels of prion mRNA as overall brain. Lowest expression was detected in kidney. Results of our study provide insight into the involvement of different organs in pathogenesis with respect to prion mRNA expression. LightCycler technology is currently considered the most precise method for nucleic acid quantification and showed to be powerful tool for further studies on prion diseases pathogenesis.

Animals↗