Three metabolic models for the production of ethanol, glycerol, and carbohydrates in yeast are optimized with respect to different production rates. While originally nonlinear, all three optimization problems are reduced in such a way that methods of linear programming can be used. The optimizations
Optimal methods for the preservation of cartilage samples in MRI and correlative biochemical studies
✍ Scribed by Kenneth W. Fishbein; Holly C. Canuto; Preeti Bajaj; Nancy Pleshko Camacho; Richard G. Spencer
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 867 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0740-3194
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
MRI studies of cartilage require the prevention of sample degradation before and during scanning and during shipment for correlative studies. Methods to achieve this include immersion in protease inhibitors (PIs), refrigeration, and freezing. In this study, bovine nasal cartilage (BNC) samples were stored in Dulbecco's phosphate‐buffered saline (DPBS), DPBS with standard PIs, or PI solution with GM6001, a potent metalloproteinase inhibitor. For each buffer, three samples were scanned at +4°C and stored at +4°C or at −20°C with thawing prior to imaging. T~2~ and magnetization transfer (MT) rate, k~m~, were measured weekly over 4 months, after which time water and glycosaminoglycan (GAG) contents were compared with those of matching tissue excised pre‐storage. Samples in DPBS exhibited increased T~2~ (+33.6% after 1 month at +4°C, P = 0.040) and decreased k~m~ (−20.6%, P = 0.004), while refrigeration in DPBS with PI and GM6001 yielded good stability (T~2~: +2.7%, P = 0.874; k~m~: −4.2%, P = 0.654 after 108 days at +4°C). Water content increased while GAG content markedly decreased in all samples. Thus, stability in cartilage MRI parameters can be optimized with appropriate storage conditions, but storage time should nonetheless be minimized. Magn Reson Med 57:866–873, 2007. Published 2007 Wiley‐Liss, Inc.
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