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Biomedical subjects

G C Manara

Publications and source records attributed to G C Manara.

61 records · Page 4Linked to original sources
PubMed1981

Darier's keratosis follicularis: an ultrastructural study during and after topical treatment with retinoic acid alone or in combination with 5-fluorouracil.

An ointment containing 0.05% retinoic acid (RA) was applied to the anterior surface of the chest in a patient suffering from Darier's keratosis follicularis. A mixture of two ointments containing equal amounts of 5% 5-fluorouracil (5-FU) and 0.05% RA was used on the dorsum of the same patient. Biopsies were taken 30 days and 70 days after treatment started. Retinoic acid gave rise to an initial disorganisation of desmosomes; the "corps ronds" and "grains" disappeared, the lacunae gradually decreased in size, and the epidermis was practically normal when the clinical manifestations of the skin had disappeared. The damage induced with the RA + 5-FU mixture was more serious, but when the skin lesions relapsed they did so later and in a less severe way than the recurrences observed after treatment with RA alone.

Darier Disease↗
PubMed1981

Fine structure of granular cell tumor of Abrikosov.

The case report illustrates the microscopical and ultrastructural findings obtained in a case of Abrikossoff's tumor. On the basis of the light and ultrastructural data a neural histogenesis is suggested.

Adult↗
PubMedDate not supplied

Adhesion molecules on the plasma membrane of epidermal cells. IV. Immunolocalization of the intercellular adhesion molecule-1 (ICAM-1, CD54) on the cell surface of a small subpopulation of keratinocytes freshly isolated from normal human epidermis.

The intercellular adhesion molecule-1 (ICAM-1) is a cell membrane glycoprotein displaying a pivvtal role in cell-cell interactions in the immune system, and is a ligand for LFA-1, which is expressed on leukocytes. ICAM-1 is expressed in different cell types, including epithelial cells in a number of organs; the universal feature on all these cells is ICAM-1 induction from very low ICAM-1 constitutive levels on unstimulated resting cells to very high ICAM-1 levels triggered by mediators released at sites of inflammation. Therefore, since a strong expression of ICAM-1 on keratinocyte (KC) surface was recently demonstrated in various inflammatory skin lesions, in this investigation we asked whether very low ICAM-1 levels might be present on the plasma membrane of unstimulated KC in normal skin. Crude epidermal cell suspensions, freshly isolated from normal human skin, were immunolabeled by anti-ICAM-1 monoclonal antibody and stained by two highly sensitive ultrastructural detection systems, namely, the immunogold (5-nm-sized particles) method and the immunogold-silver-enhancement method. The quantitative analysis of 1000 KC scrutinized under the electron microscope revealed that 17.2% KC were ICAM-1-positive, although a density per KC section (midplane) of merely 18.92 +/- 13.02 5 nm-sized particles was scored (n = 100), indicating that the amounts of ICAM-1 moieties on this KC subset are presumably low. The ICAM-1 expression on a subset of KC in normal skin might account for the trafficking to and from normal epidermis of LFA-1-positive cells, including migrating Langerhans cells and occasional leukocytes.

Cell Adhesion Molecules↗
PubMedDate not supplied

A diffusion immunogold procedure for accurate ultrastructural investigation of renal cell membrane epitopes.

A role for renal antigenic targets has been supposed and sometimes convincingly demonstrated in the development of various types of experimental glomerulonephritides. In this report we describe a reliable protocol for accurate ultrastructural investigation of antigens on the renal cell surface by means of a pre-embedding technique associated with colloidal gold staining. Sprague-Dawley rats were injected with a monoclonal antibody specific for a 90-kD cell membrane glycoprotein and killed 12 or 48 h later; after prefixation, renal fragments were cryoprotected and snap-frozen. Cryostat sections were incubated with a 5-nm colloidal gold-goat antimouse antibody, postfixed in osmium tetroxide reduced with potassium ferrocyanide and embedded in Durcupan ACM. At the glomerular level, gold granules were localized on the endothelial cell surface. In the proximal tubules uniform labelling was noticed on the brush border microvilli, followed by later marking of the basolateral membranes. By this pre-embedding immunogold method we obtained suitable histological preservation and fine resolution of the cell membrane immunoreactive sites. This procedure represents a useful tool for ultrastructural studies on the interaction of circulating antibodies with renal cell surface antigens.

Animals↗