Accuracy of ultrasound-guided intra-articular injections in guinea pig knees.

OBJECTIVE: Dunkin Hartley guinea pigs, a commonly used animal model of osteoarthritis, were used to determine if high frequency ultrasound can ensure intra-articular injections are accurately positioned in the knee joint. METHODS: A high-resolution small animal ultrasound system with a 40 MHz transducer was used for image-guided injections. A total of 36 guinea pigs were anaesthetised with isoflurane and placed on a heated stage. Sterile needles were inserted directly into the knee joint medially, while the transducer was placed on the lateral surface, allowing the femur, tibia and fat pad to be visualised in the images. B-mode cine loops were acquired during 100 µl. We assessed our ability to visualise 1) important anatomical landmarks, 2) the needle and 3) anatomical changes due to the injection. RESULTS: From the ultrasound images, we were able to visualise clearly the movement of anatomical landmarks in 75% of the injections. The majority of these showed separation of the fat pad (67.1%), suggesting the injections were correctly delivered in the joint space. We also observed dorsal joint expansion (23%) and patellar tendon movement (10%) in a smaller subset of injections. CONCLUSION: The results demonstrate that this image-guided technique can be used to visualise the location of an intra-articular injection in the joints of guinea pigs. Future studies using an ultrasound-guided approach could help improve the injection accuracy in a variety of anatomical locations and animal models, in the hope of developing anti-arthritic therapies. Cite this article: Bone Joint Res 2015;4:1-5.

The Davis dilemma: how to prevent battles over frozen preembryos.

Cryopreservation of preembryos, or the freezing of fertilized human eggs, is a procedure increasingly used by infertile couples to improve the odds of success of advanced reproductive technologies. As a consequence, divorcing couples are finding themselves in dispute over the disposition of frozen preembryos that have not been implanted. Courts have been called on to decide to whom the frozen preembryos should be awarded, but the law is unclear whether frozen preembryos should be treated as marital property, as children, or as something else. The author analyzes various arguments concerning the appropriate legal status of frozen preembryos, and suggests a new rule to settle such disputes.

Immigrating to Quebec: the demographic challenges of a province experiencing low fertility.

"This article focuses on the shifting population of Quebec, the cultural, social and political issues regarding the province's low fertility rate, and how these affect immigration policy."

Effects of temperature and pressure on the aggregation properties of an engineered elastin model polypeptide in aqueous solution.

The pressure and temperature dependence of the cloud point transition of an aqueous solution of an elastin-like polypeptide (MGLDGSMG(VPGIG)40VPLE), prepared by bacterial expression of the corresponding artificial gene, was measured. A temperature-pressure diagram was constructed over a wide range of conditions. The (VPGIG)40 solution exhibited a well-defined pressure-induced cloudpoint (Pc), as well as a temperature-induced transition (Tc). From near atmospheric pressure up to 100 MPa, Tc increased with increasing pressure, but decreased with further increases in pressure above 200 MPa. The maximum Tc was reached at 100-200 MPa. Between 10 and 25 degrees C, the Pc decreased with increasing temperature, and a broad maximum in Pc was observed in the range -10 to 0 degree C. These results are compared with our previous results on synthetic thermoresponsive vinyl polymers.