Biomedical subjects

J Mühlhauser

Publications and source records attributed to J Mühlhauser.

21 records · Page 2Linked to original sources

PubMed1990

Cell surface alteration in Epstein-Barr virus-transformed cells from patients with extreme insulin resistance.

An abnormality was detected in the morphology of the cell surface of Epstein-Barr virus-transformed lymphocytes of patients with genetic forms of insulin resistance. In cells from two patients with leprechaunism and two patients with type A extreme insulin resistance, scanning electron microscopy demonstrated a decrease in the percentage of the cell surface occupied by microvilli in cells from the patients with leprechaunism and type A insulin resistance compared with control cells. When cells from a healthy control subject and one of the patients with leprechaunism (Lep/Ark-1) were incubated with 125I-labeled insulin, there was a decrease in the percentage of 125I-insulin associated with microvilli on the cell surface. Thus, the decreased localization of insulin receptors with the microvillous region of the cell surface was in proportion to the decrease in microvilli.

Autoradiography↗

PubMed1986

Regional heterogeneity of glycoconjugate distribution in the glomerulus revealed by lectin-gold cytochemistry and SDS-PAGE.

The authors have used SDS-PAGE and lectin overlay analysis in parallel with lectin-gold cytochemistry to identify Helix pomatia lectin (HPL) binding glycoconjugates in rat kidney glomeruli. Previous work revealed HPL binding sites only beneath podocyte foot process bases, where they contact the glomerular basement membrane. It is shown here that after neuraminidase digestion of thin sections of glomeruli before incubation with HPL-gold complexes, the number of HPL binding sites is markedly increased. These new sites are mainly associated with the podocyte free surface (adjacent to the urinary space) and with capillary endothelial cells. By lectin overlays, this neuraminidase-dependent HPL binding was shown to be due to reaction of the lectin with desialylated podocalyxin. In contrast, HPL binding sites detected prior to neuraminidase digestion are associated with a novel glycoconjugate having a lower electrophoretic mobility than podocalyxin. Although any role for this glycoconjugate is at present speculative, it is strategically positioned at the site of interaction between foot process bases and the glomerular basement membrane. Its presence correlates with normal podocyte architecture, as shown by our previous studies on developmental and aminonucleoside nephrosis-associated changes in HPL binding to podocytes.

Animals↗

PubMed1986

Resorption of the unmineralized proximal part of Meckel's cartilage in the rat. A light and electron microscopic study.

The resorption of the unmineralized proximal part of Meckel's cartilage in the rat has been investigated by light microscopy and transmission electron microscopy. In the new-born animal an independent resorption area differentiates at the level of the open end of the incisor root and resorption progresses towards the proximal end of Meckel's cartilage. The process of remodelling differs from the usual process of endochondral ossification taking place in the distal part of the cartilage rod. First the perichondrium is affected, where macrophage- and fibroblast-like cells appear to degrade the unmineralized cartilage matrix. The chondrocytes in the center of the cartilage are undergoing degeneration. Finally, giant cells resembling macrophages attack the degenerating chondrocytes. Such giant cells seem to contribute to the digestion of cellular components of the cartilage rod. Thus, Meckel's cartilage provides a suitable model for studying cartilage breakdown under non-ossifying conditions.

Animals↗