Some histochemical reactions of mast cells of gerbils,hogs, armadillos and cats

Summary Mast cells of the Mongolian gerbil Meriones unguiculatus, the hog Sus scrofa, the cat Felis catus and the armadillo Pasypus novemcinctus were studied histochemically in relation to various fixation procedures, using azure A at pH 1 and 3, alcian blue at pH 1 and 2.5, diazosafranin at pH 3 and 7.8–8, and the PAS reaction. Fixations were performed in buffered 10% formol and 5% glutaraldehyde, in Kose's fluid, buffered sublimate (B4), lead nitrate and lead acetate formol.With azure A and alcian blue many mast cells were found in the gerbil with the aldehyde fixatives, fewer with the heavy metals. The diazosafranin reaction was present only in the aldehyde material, the PAS reaction was negative.In the hog, mast cells were more numerous after heavy metal fixation, fewer with aldehydes. Azure A stained metachromatically at pH 1 and 3, alcian blue reacted only at pH 1, the PAS reaction was negative, the pH 3 and 8 diazosafranin reactions were positive with all 4 fixations.In the cat, mast cells were moderately numerous with lead acetate formol, rare with formol and absent with glutaraldehyde. They stained with azure A at pH 1 and 3, with alcian blue at pH 1 and 2.5, with diazosafranin at pH 3 and 8 and by the PAS reaction.Armadillo mast cells were more numerous after heavy metal fixations, stained with azure A and alcian blue at pH 1 and 2.5 to 3, and with acid and alkaline diazosafranin.The mast cells of the 4 species vary in their requirements for aldehyde and heavy metal fixation, in their PAS reactivity and in their pH 2.5 alcian blue staining. All are sufficiently sulfated to react to cationic dyes at pH 1, but vary in PAS reactivity, indicating partial or complete sulfation. The presence of 5-hydroxytryptamine is indicated in all four species.Assisted by grant from National Cancer Institute C-04816.     

Neurogenic-committed human pre-adipocytes express CYP1A isoforms

Stem cell models offer an opportunity both for therapeutic use and for the assessment of alternative in vitro models. Human lipoaspirate is a source of adult stem cells (pre-adipocytes), which are able to differentiate into various phenotypes, such as neurogenic lineage. Here, we analyse the suitability of these in vitro models in screening exogenous compounds, such as environmental pollutants, that may affect adipose cells and neurogenic development. To evaluate neurogenic differentiation, we analysed expression of cholinergic system and acetylcholinesterase immunoreactivity. Heterocyclic derivatives of polycyclic aromatic hydrocarbons (PAHs) are often significant components of environmental contaminants. As they contain inducers of cytochrome P450 1A1 (CYP1A1), we explored the activity of CYP1A1-related enzymes, i.e. 7-ethoxycoumarin- and 7-ethoxyresorufin-O-deethylase (ECOD and EROD) in both cell systems in basal conditions and after exposure to non-cytotoxic doses of β-naphthoflavone (BNF), a well-known PAH-type inducer. Both cell models showed basal and inducible levels of ECOD. Analysis of CYP1A1 protein expression and EROD-related enzyme activity confirmed the inducibility of the CYP1A1 isoform by BNF. These results demonstrate that mesenchymal adult stem cells can constitute innovative models. We therefore propose the use of pre-adipocytes and their neurogenic derivates to evaluate the cytotoxic/biological effects of unintended exposure to contaminants.