ABSTRACT
A new type of in vivo tissue engineering system for tendon repair in situ after cut or crush of a flexor tendon is described. The system is based on the topographical reaction, alignment, migration and perhaps proliferation of tendon cells on micrometrically grooved substrates made in a biodegradable polymer. Macrophage trapping in the structure may also help to prevent inflammation. Tendon damage including crush and section injury is a fairly frequent occurrence. The conventional treatment is surgical repair, however frequently this leads, especially in hand wounds, to attachment of the tendon surface to the surrounding synovium, which is very undesirable. We present an approach based on using a biodegradable device to ensure that the healing of severed or crushed flexor tendons is aided, synovial adhesion prevented and the final result anatomically correct. The biodegradable sheath carries microgrooves fabricated into the polymer by embossing that orient and guide the cells towards each other from either side of the region of damage. After six weeks an apparently normal functional tendon is reformed.
Subject(s)
Tendons/pathology , Tissue Engineering/methods , Wound Healing , Animals , Collagen/metabolism , Macrophages/pathology , Polydioxanone , Prostheses and Implants , Rats , Synovial Fluid , Tendons/physiologyABSTRACT
The basis of the selectivity of fluorochromes routinely used to visualize the endoplasmic reticulum (ER) in live cells remains obscure. To clarify this, interactions of living cells with fluorochromes of varied physicochemical properties were analyzed experimentally and numerically using a quantitative structure activity relationship analysis (QSAR). Routine selective ER probes were found to be amphipathic, lipophilic cations with moderate-sized conjugated systems. The moderately lipophilic character permits probe uptake by passive diffusion without nonspecific accumulation in biomembranes. The moderately amphipathic character favors uptake into the ER, perhaps owing to its high concentration of zwitterionic lipid head-groups. The QSAR model rationalizes the impractical character of some ER probes mentioned in the literature, and could permit design of novel ER probes with different emission colors. The possibility of using the QSAR model as a tool to predict the accumulation of xenobiotics in the ER of living cells is illustrated by the localization of certain antipsychotic drugs in cultured cells.
Subject(s)
Endoplasmic Reticulum , Fluorescent Dyes/standards , Quantitative Structure-Activity Relationship , Animals , Antipsychotic Agents/analysis , Antipsychotic Agents/pharmacokinetics , Cations , Cells, Cultured , Fluorescent Dyes/chemistry , Hydrophobic and Hydrophilic Interactions , Microscopy, Fluorescence , Xenobiotics/analysis , Xenobiotics/pharmacokineticsABSTRACT
In this study the osteoconductive properties of strontium based ionomeric cements (ICs) named, LG125 and LG119, as well as zinc-based ICs, designated by LG130 and LG132, were compared. Wet ICs were surgically implanted into the femora of weaned Wistar rats for 4 weeks. To assess the percentage osseointegration the perimeter of the implant and the perimeter of bone in contact with the implant were measured using a pointer (the length of bone/implant interfacial contact). Osteoconduction was determined by taking six points at random around the perimeter of each ionomeric rod measuring the thickness of newly formed bone. The degree of osteoconduction was taken as the average thickness of new bone produced on the implant surface. It was found that osteoconduction was greatest in the strontium based IC implant LG125. From these studies it can be concluded that the composition LG125 might provide a useful purpose as a bone cement.
