OBJECTIVE:In the present study, we sought to develop/characterize the pain profile of a rat model of surgically induced osteoarthritis (OA). METHODS:OA was surgically induced in male Lewis rats (200-225 g) by transection of the medial collateral ligament and medial meniscus of the femoro-tibial joint. In order to characterize the pain profile, animals were assessed for a change in hind paw weight distribution (HPWD), development of mechanical allodynia, and the presence of thermal and mechanical hyperalgesia. Rofecoxib and gabapentin were examined for their ability to decrease change in weight distribution and tactile allodynia. RESULTS:Transection of the medial collateral ligament and medial meniscus of male Lewis rats resulted in rapid (<3 days) changes in hind paw weight bearing and the development of tactile allodynia (secondary hyperalgesia). There was, however, no appreciable effect on thermal hyperalgesia or mechanical hyperalgesia. Treatment with a single dose of rofecoxib (10 mg/kg, PO, day 21 post surgery) or gabapentin (100mg/kg, PO, day 21 post surgery) significantly attenuated the change in HPWD, however, only gabapentin significantly decreased tactile allodynia. CONCLUSION:The rat medial meniscal tear (MMT) model mimics both nociceptive and neuropathic OA pain and is responsive to both a selective cylooxygenase-2 (COX-2) inhibitor commonly utilized for OA pain (rofecoxib) and a widely prescribed drug for neuropathic pain (gabapentin). The rat MMT model may therefore represent a predictive tool for the development of pharmacologic interventions for the treatment of the symptoms associated with OA.

ABSTRACT: The aim of this work is to develop a mathematical model to predict the lysozyme release kinetics from crosslinked polyvinylalcohol (PVOH) into an aqueous solution. The model was developed by taking into account both the diffusion of water molecules into the polymeric film and the counter‐diffusion of the incorporated antimicrobial agent from the film into the aqueous solution. In particular, it was considered that the lysozyme release from a swelling polymer could be regarded as “anomalous diffusion” with moving boundary conditions. The water sorption kinetics of 4 films, differing for the degree of crosslink, were determined at ambient temperature (25 °C). The results obtained by fitting the model to the experimental data are satisfactory.

A two-dimensional mathematical model able to predict the time course of hydroperoxides and oxygen concentration profile inside bottled virgin olive oil during storage is presented. By simulating the behavior of the bottled virgin olive oil it was possible to assess the influence of the bottle's shape and size on the quality decay kinetics of virgin olive oil bottled in glass and plastic containers. In particular, five geometrically different containers were used to predict the storage behavior of bottled virgin olive oil. The obtained results show that the quality decay kinetics of bottled virgin olive oil greatly depends on container geometry. However, the extent to which the container's geometrical factors affect the quality decay kinetics depends on the material used to make the bottle, and on the initial value of the oxygen partial pressure in the bottle headspace.