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An essential feature of mammary gland differentiation during pregnancy is the formation of alveoli composed of polarized epithelial cells, which, under the influence of lactogenic hormones, secrete vectorially and sequester milk proteins. Previous culture studies have described either organization of cells polarized towards lumina containing little or no(More)
When primary mouse mammary epithelial cells are cultured on plastic, they rapidly lose their ability to synthesize and secrete most milk proteins even in the presence of lactogenic hormones, whereas cells cultured on released type I collagen gels show greatly enhanced mRNA levels and secretion rates of beta-casein and of some other milk proteins. We show(More)
The initial events during phagocytosis of latex beads by mouse peritoneal macrophages were visualized by high-resolution electron microscopy of platinum replicas of freeze-dried cells and by conventional thin-section electron microscopy of macrophages postfixed with 1% tannic acid. On the external surface of phagocytosing macrophages, all stages of particle(More)
The structure, distribution and composition of the extracellular matrix present around the human oocyte and in the cumulus was examined following fixation in the presence of ruthenium red. An extracellular matrix comprising granules and filaments is present in the cumulus layer, in the corona radiata, in the outer pores of the zona pellucida and in the(More)
During implantation the embryo attaches to the endometrial surface and trophoblast traverses the uterine epithelium, anchoring in the uterine connective tissue. To determine whether trophoblast can facilitate invasion of the uterus by degrading components of normal uterine extracellular matrix, mouse blastocysts were cultured on a radio-labeled(More)
Cytochrome b5 is an amphipathic microsomal protein that is anchored to the endoplasmic reticulum by a single hydrophobic transmembrane alpha-helix located near the carboxyl terminus of the protein. In yeast, cytochrome b5 provides electrons for fatty acid desaturation and ergosterol biosynthesis. High level expression of cytochrome b5 in Saccharomyces(More)
  • J Aggeler
  • 1990
Modulation of the synthesis and secretion of extracellular matrix proteins and matrix-degrading metalloproteases by rabbit synovial fibroblasts is an important model system for studying the control of tissue-specific gene expression. Induction of collagenase expression is correlated with changes in cell shape and actin filament distribution, but the role of(More)
We obtained high-resolution topographical information about the distribution of clathrin and cytoskeletal filaments on cytoplasmic membrane surfaces of macrophages spreading onto glass coverslips by both critical-point drying of broken-open cells and preparation of rotary platinum replicas. Irregular patches of the adherent ventral surface of the plasma(More)
Induction of the neutral proteinase, collagenase, is a marker for a specific switch in gene expression observed in rabbit synovial fibroblasts. A variety of agents, including 12-O-tetradecanoylphorbol-13-acetate, cytochalasins B and D, trypsin, chymotrypsin, poly(2-hydroxyethylmethacrylate), and trifluoperazine induced this change in gene expression.(More)
In the present study we provide evidence that the cytodifferentiation of primary mouse mammary epithelial cells within the alveolar-like structures formed after culture on a reconstituted basement membrane resembles development in vivo during late pregnancy and early lactation. During the first two days in culture on a basement membrane gel in the presence(More)