Lectin and proteoglycan histochemistry of feline pacinian corpuscles.

We studied carbohydrate residues of glycoproteins and proteoglycans (PGs) in peritoneal Pacinian corpuscles of five adult cats. Terminal monosaccharides of glycoproteins and related polysaccharides were identified by lectin histochemistry and the PGs and glycosaminoglycans (GAGs) by specific antibodies. The most intensive lectin staining reactions indicated an abundance of glycoconjugates with terminal mannose (Man) or sialic acid residues, but no complex-type oligosaccharides were detected within the corpuscles. Terminal fucose (Fuc) and galactose (Gal) residues typical for O-linked mucin-type glycoproteins generally associated with high water binding capacity were also absent. Antibodies against unsulfated chondroitin (C-0-S), chondroitin-4-sulfate (C-4-S), and decorin showed positive reactions in the interfibrillar spaces between the lamellae, around collagen fibers, and around the lamellae of the perineural capsule, especially in the outer parts known to contain Type II collagen. Biglycan showed a preference for the innermost part of the perineural capsule (intermediate layer), known to contain Type V collagen. Collagen V and biglycan are both linked to growth processes. Hyaluronic acid (HA), chondroitin-6-sulfate (C-6-S) chains, and a chondroitin sulfate proteoglycan (CSPG) were co-localized in the terminal glia. The study of carbohydrates with high water binding capacity may contribute to our understanding of the high viscoelasticity of Pacinian corpuscles.

Quantitative assessment of spontaneous lung metastases of human HT29 colon cancer cells transplanted into SCID mice.

The number of spontaneous lung metastases of the human colon cancer cell line HT29 transplanted into SCID mice was quantified. The lungs were sliced, randomly distributed in agar blocks and the number of lung metastases was counted for each of 39 animals. A nearly exponential increase of metastases with weight of the tumor at the implantation site was observed. This suggests that a critical tumor weight for the initiation of metastatic spread exists. Calculating the data, a simplified quantitative assessment of the metastatic load by counting ten histological sections only for the estimation of the total number of lung metastases is proposed.

Epidermal growth factor, vascular endothelial growth factor and progesterone promote placental development in rat whole-embryo culture.

The development and survival of rat embryos in whole-embryo culture is limited by the lack of any maternal blood circulation in a purely fetal placenta. If the resulting placental insufficiency could be overcome for some time by an increase of the placental exchange area, a prolonged culture period would result and facilitate the development of embryos. In the present study, several attempts to stimulate proliferation and growth of the fetal placenta were made by the addition of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and progesterone to the culture medium. Rat embryos were routinely explanted with their embryonic membranes at 10.5 days of gestation. Decidua, parietal yolk sac, Reichert's membrane and the layer of superficial trophoblastic giant cells were removed. The explants were cultured and gassed continuously for 24 h in rotating plastic tubes containing rat serum, diluted to 50% with modified COON's F12 medium. Either of the two growth factors or progesterone were added to each culture tube and a control group was cultured without any factor. After the addition of each of these factors the stimulatory effect on placental growth was assessed by morphometric evaluation of several placental parameters from semithin cross-sections: On adding each of the factors the whole cross-sectional area of the placenta significantly increased, as did the area of the fetal placental mesenchyme. VEGF also increased the area of the trophoblast, and the area of the blood vessels enclosed within the trophoblast, by an average of 9.4% and 23.6%, respectively. Thus, VEGF treatment resulted in a measurable extension of the exchange area of the fetal placenta.

Epithelial glycoprotein-2 expression is subject to regulatory processes in epithelial-mesenchymal transitions during metastases: an investigation of human cancers transplanted into severe combined immunodeficient mice.

The human cell-surface antigen epithelial glycoprotein-2 recognized by the monoclonal antibody MOC-31 is an epithelial tumour-associated glycoprotein expressed in non-squamous carcinomas. MOC-31 immunoreactivity was investigated in human breast, colon, ovarian and lung cancer cell lines, grown either in vitro or in severe combined immunodeficient (SCID) mice as solid tumours and/or metastases. Three of four small-cell lung cancer cell lines (NCI-H69, OH3 and SW2) and three of four ovarian cancer cell lines (SoTu 1, 3 and 4) expressed epithelial glycoprotein-2. In contrast, all three breast (MCF-7, BT20, T47D) and all three colon (HT29, CACO2, SW480) cancer cell lines strongly reacted with monoclonal antibody MOC-31. A notable difference in MOC-31 immunoreactivity was observed in spontaneously formed lung metastases of HT29 colon cancer cells. Whereas larger metastases (> 30 cells) reacted with a similar staining pattern to the primary tumour, smaller metastases did not. These findings indicate that differentiation processes during the epithelial-mesenchymal transition occur in metastases, which lead to a transient loss of epithelial glycoprotein-2 expression during the migratory and early post-migratory period. This loss of antigen expression indicates that the process of metastases formation is a regulatory event, and this transient loss of antigen expression might represent a potential obstacle to antibody-based therapy in the setting of minimal residual disease.