1. Human skin fibroblasts internalize homologous sulphated proteoglycans by adsorptive endocytosis. Endocytosis rate is half maximal when the concentration of the proteoglycans is 0.1 nM. At saturation, a single fibroblast may endocytose up to 8 X 10(6) proteoglycan molecules/h. 2. The kinetics of prote;glycan binding to the cell surface suggest the presence of 6 X 10(5) high-affinity binding s...

The predominant proteoglycan present in cartilage is the large chondroitin sulfate proteoglycan 'aggrecan'. Following its secretion, aggrecan self-assembles into a supramolecular structure with as many as 50 monomers bound to a filament of hyaluronan. Aggrecan serves a direct, primary role providing the osmotic resistance necessary for cartilage to resist compressive loads. Other proteoglycans ...

Newly synthesized rat glomerular [35S]proteoglycans were labelled in vivo after injecting Na2[35S]SO4 intraperitoneally. At the end of the labelling period (7 h) the kidneys were perfused in situ with 0.01% (w/v) cetylpyridinium chloride. This fixed proteoglycans in the tissue and increased their recovery 2-3-fold during subsequent isolation of glomeruli from the renal cortex. The glomeruli wer...

Proteoglycans in mineralized (0.5 M-EDTA/4 M-guanidinium chloride-extractable) and non-mineralized (4 M-guanidinium chloride-extractable) matrices synthesized by a mouse osteoblastic-cell line MC3T3-E1 were characterized at different phases of mineralization in vitro. Cell cultures were labelled with [35S]sulphate and either [3H]glucosamine or 3H-labelled amino acids. At the mineralization phas...

Heparan sulfate proteoglycans are key molecules found associated with the cell surface and extracellular matrix (ECM). These macromolecules seem to be essential to achieve terminal skeletal muscle differentiation. In this review, we present data about the types of beparan suifate proteoglycans present in skeletal muscle cells, how their expression changes during differentiation and we propose s...

OBJECTIVE To investigate if the increased proteoglycans in patellar tendinopathy involves a qualitative change in the types of proteoglycans. DESIGN This is an observational study based on the biochemical analysis of proteoglycans. SETTING : University Teaching Hospital. PATIENTS Patellar tendon samples from 12 patients with patellar tendinopathy and 12 healthy controls were collected and...

The effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), an active form of vitamin D3, on the metabolism of proteoglycans by an osteoblastic cell line MC3T3-E1 were studied. Cells metabolically labeled with [35S]sulfate and/or [3H]glucosamine synthesized large and small dermatan sulfate proteoglycans and heparan sulfate proteoglycan. The incorporation of [35S]sulfate into proteoglycans for 1 h w...

Rats were implanted with mini osmotic pumps delivering sodium [35S]sulphate and their newly synthesized proteoglycans were labelled over a 146 h period (steady-state labelling). Proteoglycan turnover was measured in vivo using a chase protocol. Glomerular proteoglycans were recovered quantitatively and the perlecan present was isolated by immunoprecipitation. The procedure allows newly synthesi...

Objective(s) Articular cartilage tissue defects cannot be repaired by the proliferation of resident chondrocytes. Autologous chondrocyte transplantation (ACT) is a relatively new therapeutic approach to cover full thickness articular cartilage defects by in vitro grown chondrocytes from the joint of a patient. Therefore, we investigated the redifferentiation capability of human chondrocytes ma...

Single-gene disorders occur when mutation in a gene causing alteration of gene function while in multifactorial disorders, mutations occur in multiple genes, and these are usually coupled with environmental causes. In addition, in a multifactorial disorder such as diabetes, the complication is under the influence of different genes. For example, in diabetic retinopathy many genes are involved i...