Hepatic oval cells (HOC) are thought to be a type of facultative stem cell that arises as a result of certain forms of hepatic injury. A new and more efficient model has been established to activate the oval cell compartment in mice by incorporating 3,5-diethoxycarbonyl-1,4-dihydro-collidine (DDC) in a standard chow at a concentration of 0.1%. At the present time, very few markers exist for the mouse oval cells. One accepted marker is A6, an uncharacterized epitope recognized by mouse hepatic oval cells and it is accepted to be an oval cell marker. Sca-1 is a cell surface marker used to identify hematopoietic stem cells in conjunction with Thy-1؉, CD34؉, and lineage-specific markers. Both the CD34 and Sca-1 antigens are not normally expressed in adult liver, but are expressed in fetal liver, presumably on the hematopoietic cells. We report herein that mouse oval cells express high levels of Sca-1 and CD34, as well as CD45 surface proteins. Immunohistochemistry revealed that the cells expressing Sca-1/CD34/CD45 were indeed oval cells because they co-expressed the oval cell-specific marker A6 (94.57% ؎ 0.033%), as well as alpha-fetoprotein (AFP) (75.92% ؎ 0.071%). By using Sca-1 antibody in conjunction with magnetic activated cell sorting (MACS), followed with a flow cytometric cell sorting (FACS) method for CD34 and CD45, we have developed a rapid oval cell isolation protocol with high yields of greater than 90%. In conclusion, we have an efficient murine model for the production and isolation of large numbers of highly purified oval cells. Our system works with most strains of mouse, which will facilitate both in vivo and in vitro studies of mouse hepatic oval cells. ( T he majority of the information on hepatic oval cells (HOCs) is derived from a series of highly reproducible rat models developed over the years. Until recently, murine models for oval cell activation and proliferation have been complicated and arduous, producing low numbers of oval cells with varying results. This has greatly limited the usefulness of mice as a genetic system to study the mechanisms of oval cell activation and differentiation. To take advantage of the immense power of mouse genetics we sought to define a reproducible, strain-independent, high-yield model for murine oval cell proliferation and purification. Recently, a method was described that is reproducible and generates large numbers of murine oval cells based on morphology. The model used to activate the oval cell compartment in mice is a diet of 3,5-diethoxycarbonyl-1,4-dihydro-collidine (DDC) at a concentration of 0.1% in a standard rodent chow for 4 to 6 weeks. Morphologically, the mouse oval cells share many similarities to rat oval cells; they are small in size (approximately 10 m), with a large nucleus to cytoplasm ratio. They radiate from the periportal region forming primitive ductular structures with poorly defined lumen, like that observed in the various rat models. [1][2][3] We used this diet, combined with antibody-based oval cell isolation techniques, to produce...

MII was 90% successful differentiating between normal dogs and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Abnormal intervertebral disc space localization using ROI mean temperature analysis was not successful. MII patterns 10 weeks after surgery do not normalize.

BackgroundDiscectomies are a common surgical treatment for disc herniations in the canine spine. However, the effect of these procedures on intervertebral disc tissue is not fully understood. The objective of this study was to assess degenerative changes of cervical spinal segments undergoing discectomy procedures, in vivo.ResultsDiscectomies led to a 60% drop in disc height and 24% drop in foraminal height. Segments did not fuse but showed osteophyte formation as well as endplate sclerosis. MR imaging revealed terminal degenerative changes with collapse of the disc space and loss of T2 signal intensity. The endplates showed degenerative type II Modic changes. Quantitative MR imaging revealed that over 95% of Nucleus Pulposus tissue was extracted and that the nuclear as well as overall disc hydration significantly decreased. Histology confirmed terminal degenerative changes with loss of NP tissue, loss of Annulus Fibrosus organization and loss of cartilage endplate tissue. The bony endplate displayed sclerotic changes.ConclusionDiscectomies lead to terminal degenerative changes. Therefore, these procedures should be indicated with caution specifically when performed for prophylactic purposes.