Biomedical subjects

P Sisi

Publications and source records attributed to P Sisi.

3 recordsLinked to original sources

PubMed1998

Patterned acquisition of skin barrier function during development.

Skin barrier function is conferred by the outer layer of epidermis, the stratum corneum, and is essential for terrestrial life. Quantitative trans-epidermal water loss assays show that barrier forms late in embryogenesis, permitting the foetus to survive a terrestrial environment at birth. Using qualitative in situ assays for skin permeability, we show that barrier forms in a patterned manner late in mouse gestation. Barrier forms at specific epidermal sites, then spreads around the embryo as a moving front. The moving front of permeability change is accompanied by multiple changes in the outer, stratum corneum-precursor cells. We use the permeability assays to show that final stages of cornified envelope assembly are coordinated with initial stages of barrier formation. Hence the whole-mount permeability assays record developmental acquisition of a known, essential component of the adult barrier. We demonstrate the authenticity of the whole-mount assays after maternal glucocorticoid therapy (known to accelerate barrier formation) and in additional species including the rat where barrier formation is well characterized by TEWL assay (Aszterbaum, M., Menon, G. K., Feingold, K. R. and Williams, M. L. Pediatr. Res. 31, 308-317). The demonstration of patterned barrier formation in other species suggests patterned change as the universal mode of embryonic barrier acquisition. These results highlight the importance of patterning as a mode of epidermal maturation during development.

Animals↗

PubMed1996

Localization of bradykinin type II receptor mRNA in human endometrium.

Bradykinin is a nonapeptide inflammatory agent that in the endometrium stimulates stromal cell proliferation, prostaglandin synthesis and electrogenic ion transport. The expression of bradykinin type II (B2) receptor mRNA was examined by in-situ hybridization using 35S-labelled riboprobe in human endometrium to determine its temporal and spatial pattern of distribution throughout the menstrual cycle. The B2 receptor mRNA was expressed in proliferative and secretory endometrium. In the early proliferative endometrium there were low levels of B2 receptor mRNA over both the glands and stromal cells. The signal increased in intensity and was localized over the glands with low levels of hybridization in the stroma in the late proliferative endometrium. In the early secretory endometrium B2 receptor mRNA was highly expressed in the endometrial glands. The strong hybridization signal persisted and in late secretory endometrium both glandular and stromal cells expressed B2 receptor mRNA. The apparent increase in B2 receptor mRNA in the secretory endometrium suggests that bradykinin acting via B2 receptor may play a role in the increased vascular permeability and vasodilatation associated with implantation.

Adult↗

PubMed1996

Localisation of placenta growth factor (PIGF) in human term placenta.

Placenta growth factor (PlGF) is a growth factor which belongs to the vascular endothelial growth factor (VEGF) family and is known to bind to the fms-like tyrosine kinase receptor (flt-1). Using Western blot analysis a 50 kDa band was identified in placental protein extract which corresponded to PlGF homodimer. Immunoreactive PlGF was localised to the vasculosyncytial membrane and in the media of large blood vessels of the placental villi, while staining within the mesenchyme was weak and diffuse. There was moderate staining for PlGF in discrete cells in the chorion and no staining in the epithelial layer of the amnion. The maternal decidual cells showed strong staining for PlGF immunoreactive protein. PlGF mRNA was predominantly expressed by the vasculosyncytial membrane of villous trophoblast, whilst there was no apparent expression of PlGF mRNA within the villous mesenchyme. These results suggest that PlGF may be an important paracrine factor for vascular endothelial cells in placental angiogenesis and an autocrine mediator of trophoblast function.

Blotting, Western↗