High resolution MRI evaluation of meniscal volume and anthropometric correlations.

The purpose of this study was to digitally determine meniscal volumes, and compare them with linear and surface area anthropometric measurements to evaluate these measurements for meniscal allograft sizing. Eighteen subjects (10 male and 8 female; mean age 37.5 years) underwent 3.0 T knee magnetic resonance imaging (MRI) of the dominant leg. The following morphometric measurements were evaluated: medial meniscal volume (MMV), lateral meniscal volume (LMV), tibial plateau width (TPW), width of the femoral condyles (WFC), and tibial plateau surface area (TPSA). MMV and LMV were compared to TPW, WFC, and TPSA. Meniscal volume and TPW were correlated to height and body-mass index (BMI) and stratified by gender. Statistical analysis included coefficient of determination (r(2)) between MRI-based MMV, LMV, TPW, TPSA, WFC, height, BMI, and gender. Significance was set at the P = 0.05 level. The mean MMV was 2275 mm(3) and the mean LMV was 2102 mm(3). TPW correlated well with meniscal volumes (r(2) > 0.62). WFC and TPSA correlated with meniscal volumes in the range of 0.40 < r(2) < 0.61. Height, BMI, and gender correlated poorly with total meniscal volume and TPW with values of r(2) < 0.44. Medial and lateral menisci have statistically similar volumes. TPW had the greatest utility for volumetric meniscal sizing. MRI-based TPW can be considered as a statistically accurate measurement for determining meniscal volumes and meniscal size.

Effect of aging, caloric restriction, and uncoupling protein 3 (UCP3) on mitochondrial proton leak in mice.

Mitochondrial proton leak may modulate reactive oxygen species (ROS) production and play a role in aging. The purpose of this study was to determine proton leak across the life span in skeletal mitochondria from calorie-restricted and UCP2/3 overexpressing mice. Proton leak in isolated mitochondria and markers of oxidative stress in whole tissue were measured in female C57BL/6J mice fed ad-libitum (WT-Control) or a 30% calorie-restricted (WT-CR) diet, and in mice overexpressing UCP2 and UCP3 (Positive-TG), their non-overexpressing littermates (Negative-TG) and UCP3 knockout mice (UCP3KO). Proton leak in WT-CR mice was lower than that of control mice at 8 and 26 months of age. The Positive-TG mice had greater proton leak than the Negative-TG and UCP3KO mice at 8 months of age, but this difference disappeared by 19 and 26 months. Lipid peroxidation was generally lower in WT-CR vs. WT-Control mice and UCP3KO mice had greater concentrations of T-BARS (thiobarbituric acid reactive substances, a measure of lipid peroxidation) than did Positive-TG and Negative-TG. The results of this study indicate that sustained increases in muscle mitochondrial proton leak are not responsible for alterations in life span with calorie restriction or UCP3 overexpression in mice. However, UCP3 may contribute to the actions of CR through mechanisms distinct from increasing basal proton leak.

Cats are able to adapt protein oxidation to protein intake provided their requirement for dietary protein is met.

Cats require more dietary protein than noncarnivorous species. Earlier work showed that cats lack the ability to regulate hepatic urea cycle enzymes in response to dietary protein concentration. We thus hypothesized that cats are unable to fully adapt protein oxidation to protein intake, particularly at low-protein concentrations. We used indirect respiration calorimetry to assess cats' ability to adapt substrate oxidation to diets containing different concentrations of protein, including 1 below their protein requirement. Nine cats (5 males and 4 females; 2.7 +/- 0.5 y; 4.49 +/- 0.19 kg) consumed each of 4 semipurified diets containing 7.5% [low protein (LP(3))], 14.2% [adequate protein (AP)], 27.1% [moderate protein (MP)], and 49.6% [high protein (HP)] of metabolizable energy from protein in a modified crossover design, beginning with the MP diet and then consuming the remaining diets in random order. After adaptation to each diet, cats completed a 5-d nitrogen balance trial and at least 2 12-h indirect calorimetry measurements. There was a significant effect of diet on protein oxidation (P < 0.0001), which measured 10.4 +/- 0.5, 14.1 +/- 1.0, 25.0 +/- 1.7, and 53.2 +/- 1.7% of total energy expenditure for the LP, AP, M,P and HP diets, respectively. The ratio of protein oxidation:protein intake was higher with the LP diet (1.39 +/- 0.07) than the other 3 diets (AP, 1.00 +/- 0.07; MP, 0.93 +/- 0.06; HP, 1.07 +/- 0.03; P < 0.0001), indicating a net loss of protein with the LP diet. Thus, cats are able to adapt protein oxidation to a wide range of dietary protein concentrations, provided their minimum protein requirement is met.

Energy restriction results in a mass-adjusted decrease in energy expenditure in cats that is maintained after weight regain.

Dietary energy restriction (ER) is used to treat obesity in cats but it is often unsuccessful. The purpose of this study was to determine whether ER results in a sustained decrease in mass-adjusted energy expenditure (EE) that may oppose weight loss and promote weight regain. EE and body composition were measured in 10 adult neutered cats at 3 time points: baseline (obese cats), during weight loss (40% ER), and following weight regain. The cats started with a body weight (BW) of 6.1 +/- 0.30 kg, body condition score (BCS) of 7.6 +/- 0.14 (on a 9-point scale), and fat body mass (FM) of 38 +/- 1.0% of BW. After weight loss, BW was 5.0 +/- 0.19 kg, BCS was 5.5 +/- 0.07 kg, and FM was 31 +/- 1.6% (P < 0.01). After weight regain, BW was 6.2 +/- 0.30 kg, BCS was 7.7 +/- 0.16, and FM was 42 +/- 1.8% (P < 0.01). Total EE decreased from 1258 +/- 33.7 kJ/d to 1025 +/- 39.6 kJ/d during weight loss (P < 0.001). After weight regain, EE was still lower than baseline (1103 +/- 41.5 kJ/d, P < 0.001). Energy intake (EI) at baseline (1337 +/- 50.6 kJ/d) was higher than EI after weight loss and regain (1217 +/- 61.2 kJ/d), resulting in no differences in energy balance (78 +/- 30.4 and 104 +/- 35.4 kJ/d, respectively, P = 0.581). These results support the hypothesis that ER results in a mass-adjusted decrease in EE in cats that is maintained after weight regain.

Comparison of the total phenolic and ascorbic acid content of freeze-dried and air-dried marionberry, strawberry, and corn grown using conventional, organic, and sustainable agricultural practices.

Secondary phenolic metabolites play an important role in plant defense mechanisms, and increasing evidence indicates that many are important in human health. To date, few studies have investigated the impact of various agricultural practices on levels of secondary plant metabolites. To address this issue, the total phenolic (TP) content of marionberries, strawberries, and corn grown by sustainable, organic, or conventional cultural practices were measured. Additionally, the effects of three common postharvest processing treatments (freezing, freeze-drying, and air-drying) on the TP content of these agricultural products were also investigated. Statistically higher levels of TPs were consistently found in organically and sustainably grown foods as compared to those produced by conventional agricultural practices. In all samples, freeze-drying preserved higher levels of TPs in comparison with air-drying.