Objective-To compare the chondrogenic potential of adult equine mesenchymal stem cells derived from bone marrow (MSCs) or adipose tissue (ASCs).Study Design-In vitro experimental study. Animals-Adult Thoroughbred horses (n = 11).Methods-BM (5 horses; mean [± SD] age, 4 ± 1.4 years) or adipose tissue (6 horses; mean age, 3.5 ± 1.1 years) samples were obtained. Cryopreserved MSCs and ASCs were used for pellet cultures in stromal medium (C) or induced into chondrogenesis ± transforming growth factor-3 (TGFβ 3 ) and bone morphogenic factor-6 (BMP-6). Pellets harvested after 3, 7, 14, and 21 days were examined for cross-sectional size and tissue composition (hematoxylin and eosin), glycosaminoglycan (GAG) staining (Alcian blue), collagen type II immunohistochemistry, and by transmission electron microscopy. Pellet GAG and total DNA content were measured using dimethylmethylene blue and Hoechst DNA assays.Results-Collagen type II synthesis was predominantly observed in MSC pellets from Day 7 onward. Unlike ASC cultures, MSC pellets had hyaline-like matrix by Day 14. GAG deposition occurred earlier in MSC cultures compared with ASC cultures and growth factors enhanced both MSC GAG concentrations (P<.0001) and MSC pellet size (P<.004) after 2 weeks in culture. Conclusion-EquineMSCs have superior chondrogenic potential compared with ASCs and the equine ASC growth factor response suggests possible differences compared with other species.Clinical Relevance-Elucidation of equine ASC and MSC receptor profiles will enhance the use of these cells in regenerative cartilage repair.

This study demonstrates that NF-kappaB blockade with PDTC mitigates oxidative stress and improves mitochondrial structural integrity directly, through down-regulation of increased oxygen-free radicals, thereby increasing ATP synthesis and thus restoring cardiac function in type II diabetes.

The pyrenoid is a proteinaceous structure found in the chloroplast of most unicellular algae. Various studies indicate that ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is present in the pyrenoid, although the fraction of Rubisco localized there remains controversial. Estimates of the amount of Rubisco in the pyrenoid of Chlamydomonas reinhardtii range from 5% to nearly 100%. Using immunolocalization, the amount of Rubisco localized to the pyrenoid or to the chloroplast stroma was estimated for C. reinhardtii cells grown under different conditions. It was observed that the amount of Rubisco in the pyrenoid varied with growth condition; about 40% was in the pyrenoid when the cells were grown under elevated CO 2 and about 90% with ambient CO 2 . In addition, it is likely that pyrenoidal Rubisco is active in CO 2 fixation because in vitro activity measurements showed that most of the Rubisco must be active to account for CO 2 -fixation rates observed in whole cells. These results are consistent with the idea that the pyrenoid is the site of CO 2 fixation in C. reinhardtii and other unicellular algae containing CO 2 -concentrating mechanisms.Pyrenoids are electron-dense structures that are found in the plastids of most algae. When pyrenoids are isolated, the most abundant protein present is Rubisco (Kuchitsu et al., 1991; McKay and Gibbs, 1991; Okada, 1992). However, the amount of Rubisco present in the pyrenoid is controversial. Estimates of the amount of Rubisco in the pyrenoid versus the amount in the entire chloroplast range from 60% or higher (Vladimirova et al., 1982; Lacoste-Royal and Gibbs, 1987; Morita et al., 1997) to as low as 5% (Sü ss et al., 1995).The function of Rubisco in the pyrenoid is also unclear. Lacoste- Royal and Gibbs (1987) found that a higher percentage of Rubisco was localized to the pyrenoid in stationary cells rather than in actively growing cells of Chlamydomonas reinhardtii, an observation that is consistent with the hypothesis that the pyrenoid is a storage body. Sü ss et al. (1995) interpreted their localization data to indicate that there were two forms of Rubisco in C. reinhardtii: form I, which bound to the thylakoid membranes in the stroma, and form II, which was found in the pyrenoid. They further speculated that the pyrenoid-localized form II might function as part of the CO 2 -concentrating mechanism.In photosynthetic organisms that possess a CO 2 -concentrating mechanism, Rubisco has a very specific localization. In higher plants with C4-type photosynthesis, Rubisco is specifically localized to chloroplasts of bundlesheath cells (Hatch, 1992). In unicellular cyanobacteria with CO 2 -concentrating mechanisms, Rubisco is specifically localized to structures known as carboxysomes (Allen, 1984; Codd and Marsden, 1984). Recent studies of the cyanobacteria's CO 2 -concentrating mechanism indicate that HCO 3 Ϫ accumulated by the cell is dehydrated specifically in the carboxysome, where the resulting CO 2 can be fixed before leaking out of the cell (Badger and Pric...