Quantitative studies are commonly realised in the biomedical research to compare RNA expression in different experimental or clinical conditions. These quantifications are performed through their comparison to the expression of the housekeeping gene transcripts like glyceraldehyde-3-phosphate dehydrogenase (G3PDH), albumin, actins, tubulins, cyclophilin, hypoxantine phosphoribosyltransferase (HRPT), L32. 28S and 18S rRNAs are also used as internal standards. In this paper, it is recalled that the commonly used internal standards can quantitatively vary in response to various factors. Possible variations are illustrated using three experimental examples. Preferred types of internal standards are then proposed for each of these samples and thereafter the general procedure concerning the choice of an internal standard and the way to manage its used are discussed. © 1999 Elsevier Science B.V. All rights reserved.Keywords: Internal standards; Housekeeping genes; RNase protection; RT-PCR www.elsevier.com/locate/jbiotec Quantitative assays widely use housekeeping gene transcripts as b-actin, glyceraldehyde-3-phosphate dehydrogenase (G3PDH) or L32 whose presumed stable expression allows quantification of other expressions, for example those of cytokines, by comparison to this internal standard. In this paper, a series of in vivo and in vitro models are presented using housekeeping genes showing in certain cases the limits at the use of such internal standards. Different possible methods enabling the management of this problem will be discussed.The study of biological regulations is very often correlated to quantification assays, which can be related to proteins or RNA. This paper will discuss the problem of mRNA quantification.Abbre6iations: G3PDH, glyceraldehyde-3-phosphate dehydrogenase; HPRT, hypoxantine phosphoribosyltransferase; PMA, phorbol 10-myristate 13-acetate.

No abstract

Serum level of placental growth hormone is raised in pregnancy rhinitis and may be involved in its pathogeny. Pregnancy rhinitis does not significantly raise weight gain or serum levels of estradiol, progesterone, or insulinlike growth factor I.

A critical step in establishment of human pregnancy is the invasion of the uterus wall by the extravillous cytotrophoblast (EVCT), a process regulated by multiple autocrine and paracrine factors. Hormones belonging to the GH/prolactin family are expressed at the maternofetal interface. Because they are involved in cell motility in various models, we examined the possible regulatory role of human placental GH (hPGH) in EVCT invasiveness. By using an in vitro invasion model, we found that EVCT isolated from first-trimester chorionic villi and cultured on Matrigel secreted hPGH and expressed human GH receptor (hGHR). These data were confirmed by in situ immunohistochemistry. EVCT expressed the full-length and truncated forms of hGHR, and the Janus kinase-2/signal transducer and activator of transcription factor-5 signaling pathway was activated in EVCT by hPGH treatment. Strong hPGH and hGHR expression was observed when EVCT invaded Matrigel and moved through the pores of the filter on which they were cultured. hPGH stimulated EVCT invasiveness, and this effect was inhibited by a Janus kinase-2 inhibitor. Interestingly, hPGH was more efficient than pituitary GH in stimulating EVCT invasiveness. These results offer the first evidence for a placental role of hPGH and suggest an autocrine/paracrine role of hPGH in the regulation of trophoblast invasion.

No abstract