Engineering a biological joint.
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Biomedical subjects
D Zaleske
Publications and source records attributed to D Zaleske.
Effects of hyaluronan on engineered articular cartilage extracellular matrix gene expression in 3-dimensional collagen scaffolds.
Hyaluronan (HA) is a component of cartilage matrix with known effects on chondrocytes. We tested the effects of adding HA to 3-dimensional (3-D) collagen. sponges on chondrocyte function in vitro. Bovine articular chondrocytes isolated by collagenase digestion were injected into either collagen or HA/collagen scaffolds comprising different amounts of HA (2, 5, 10, and 14% w/w). Expression of aggrecan and type II collagen genes was measured by gene-specific quantitative competitive reverse transcriptase-polymerase chain reactions, and the extracellular matrix was estimated by histomorphometrical analyses. After 7-day culture, the chondrocytes in 2% (w/w) HA sponges expressed fourfold more mRNA transcripts for type II collagen (p = 0.002) and twofold more mRNA transcripts for aggrecan (p = 0.022) than in control collagen sponges. Furthermore, there was 45% more extracellular matrix in 2% (w/w) HA sponges and 43% less matrix in the 10% (w/w) HA sponges compared with plain collagen sponges (p > 0.05). In sum, a small amount of HA in 3-D collagen scaffolds enhanced chondrogenesis, but a greater amount was inhibitory. This 3-D system represents a novel tool to identify mechanisms by which extracellular matrix molecules influence chondrocyte function. Further, these results show the potential for modifying scaffolds to improve production of engineered cartilage for in vivo applications.
Aggrecans↗
A complex bilateral polysyndactyly disease locus maps to chromosome 7q36.
We demonstrated that the gene responsible for a congenital limb deformity (polysyndactyly) maps to chromosome 7q36 in a large family. Pre- and postaxial anomalies of the extremities are inherited in this family as an autosomal dominant trait. The disease locus is closely linked to D7S550 (maximum lod score = 6.85, theta = 0). This region is homologous to a segment of mouse chromosome 5, where the mutations hammer toe (HM) and hemimelic extra toes (HX) have been mapped. These data suggest that human chromosome 7q36 and the homologous region of mouse chromosome 5 contain genes involved in limb pattern formation.
Base Sequence↗
Magnetic resonance imaging of the epiphysis: an experimental study.
The purpose of this study was to determine if metabolically altered cartilage could be distinguished from normal cartilage in the epiphysis by magnetic resonance imaging. Epiphysis from ten New Zealand White rabbits and five newborn lambs were imaged before and after heat-killing. The physiological change produced was documented with tritiated thymidine and radioactive sulfate autoradiography. Magnetic resonance imaging could detect differences in the tissues produced by heat-killing. The changes were most pronounced in the marrow, less pronounced in the epiphyseal cartilage and least pronounced but still detectable in the growth plate.
Animals↗