Chemical form of dietary l‐Carnitine affects plasma but not tissue Carnitine concentrations in male Sprague–Dawley rats

In Experiment 1, rats (n = 54) were randomly assigned to control or one of the four sources of l ‐Carnitine supplemented at either 100 or 200 μmol/kg/day and were allowed to acclimate for 14 days. Following a 12‐h fast, plasma samples were obtained at 0, 5, 10, 15, 30, 60, 120, 240, 480 and 720 min after l ‐Carnitine feeding and assayed for free l ‐Carnitine concentration. Plasma‐free l ‐Carnitine levels were affected by time after treatment intake (p < 0.0001) and l ‐Carnitine source (p < 0.0001). The time × source interaction was not statistically significant (p = 0.99). In Experiment 2, rats (n = 54) were randomly assigned to control or one of the four sources of l ‐Carnitine at either 100 or 200 μmol/kg/day and were acclimated as in experiment 1. Rats were sacrificed 120 min after feeding. Samples of liver and skeletal muscle were obtained and assayed for free l ‐Carnitine concentration. Neither skeletal muscle (p = 0.44) or liver (p = 0.59) tissue concentrations of l ‐Carnitine were affected by any l ‐Carnitine source as compared with the control. We conclude that some differences exist in plasma concentrations of free l ‐Carnitine following ingestion of different chemical forms of l ‐Carnitine. It is unclear if these differences in the circulating concentration of free l ‐Carnitine translate into any physiological differences for the animal. In this study, chemical form of l ‐Carnitine had no effect on skeletal muscle or liver tissue concentrations of l ‐Carnitine in young male Wistar rats.     

Vertical patellar position in large-breed dogs with clinically normal stifles and large-breed dogs with medial patellar luxation

OBJECTIVE: To further define vertical patellar position, as measured by the ratio of patellar ligament length to patellar length (L:P), in large-breed dogs with clinically normal stifles and compare that to the L:P of large-breed dogs with medial patellar luxation (MPL). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Large-breed dogs (n = 50) with clinically normal stifle joints and 30 large-breed dogs with MPL. METHODS: Large-breed dogs with clinically normal stifle joints or MPL were identified and divided into groups (NORM and MPL, respectively). L:P values were determined for each dog by 4 observers from single lateral stifle radiographs. L:P was compared between NORM and MPL groups and 95% confidence intervals (CIs) were calculated. RESULTS: All 4 observers found a significantly higher L:P (more proximally positioned patella) for the MPL group compared with the NORM group. Overall mean (+/-SEM) L:P were: NORM, 1.71+/-0.020 and MPL, 1.87+/-0.025. The 95% CI was determined to be 1.45-1.97 for the NORM group and 1.57-2.17 for the MPL group. CONCLUSIONS: Large-breed dogs with MPL had a significantly more proximal vertical patellar position compared with large-breed dogs with clinically normal stifles. Large-breed dogs with L:P values >1.97 are considered to have patella alta. CLINICAL RELEVANCE: Proximal displacement of the patella within the femoral trochlear groove may play a role in MPL in large-breed dogs.     

Cellular model for induction of drip loss in meat

Drip loss from porcine muscle (M. longissimus dorsi) contained high concentrations of K(+) ( approximately 135 mM) and organic osmolytes, for example, taurine ( approximately 15 mM), as well as significant amounts of protein ( approximately 125 mg.mL(-1)). Thus, the drip reflects release of intramuscular components. To simulate events taking place at the time of slaughter and leading to release of osmolytes and subsequent formation of drip loss, C2C12 myotubes were exposed to anoxia and reduction in pH (from 7.4 to 6.0). Anoxia and acidification increased the cellular Ca(2+) concentration ([Ca(2+)](i)) at a rate of 22-32 nM.min(-)(1). The anoxia-induced increase in [Ca(2+)](i) was mainly due to influx via sarcolemmal Na(+) channels. As mammalian cells swell and release lysophospholipids during anoxia, C2C12 cells and primary porcine muscle cells were exposed to either hypotonic shock or lysophosphatidylcholine (LPC) and the release of taurine was followed. The swelling-induced taurine efflux was blocked in the presence of the anion channel blocker (DIDS), the 5-lipooxygenase inhibitors (ETH 615-139 and NDGA) but unaffected by the presence of vitamin E. In contrast, the LPC-induced taurine release was unaffected by DIDS but abolished by antioxidants (butylated hydroxytoluene and vitamin E). Thus, stress-induced taurine release from muscles may precede by two different mechanisms, one being 5-lipooxygenase dependent and the other involving generation of reactive oxygen species. A model for the cellular events, preceding formation of drip in meat, is presented.     

Development and validation of instruments measuring body image and body weight dissatisfaction in South African mothers and their daughters

OBJECTIVE: We sought to validate questionnaires concerning body image perception, body size dissatisfaction and weight-related beliefs in multi-ethnic South African mothers and their daughters. SETTINGS AND SUBJECTS: Girls attending primary school (ages 9-12 years, n = 333) and their mothers (n = 204) were interviewed regarding their demographics and body image. Weight, height and skinfold thicknesses were measured. Body image questions and body mass index (BMI) were compared with silhouettes adapted from the Pathways Study for girls and Stunkard's body image figures for mothers. A Feel-Ideal Difference (FID) index score was created by subtracting the score of the silhouette selected by the participants as 'Ideal' from the one selected as most closely representing their current appearance or 'Feel'. We hypothesised that a higher FID index score would be associated with greater body size dissatisfaction. RESULTS: BMI percentiles in girls (r = 0.46, P < 0.05) and BMI in mothers (r = 0.68, P < 0.05) were positively correlated with the selected silhouettes based on size. Participants who reported feelings of being 'fat' and those who perceived that their family and friends were more dissatisfied with their body size had significantly higher FID index scores. Scores were lower in black than white girls (all P<0.05). No differences were found in FID index scores between ethnic groups of mothers. Internal reliability of the 'thin' and 'fat' belief constructs for girls was demonstrated by standardised Cronbach's alpha values > or = 0.7. CONCLUSION: Silhouettes, FID index, 'fat' and 'thin' belief constructs (in girls) are age-appropriate, culturally sensitive and can be used in further intervention studies to understand body image.     

Growth and N nutrition, monitored by enzyme assays, in a hardwood plantation: effects of mulching materials and glyphosate application

The effects of mulching materials (black plastic and straw) and herbicide application (glyphosate) on growth and nitrogen nutrition of butternut (Juglans cinerea), white ash (Fraxinus americana) and bur oak (Quercus macrocarpa) were studied in a plantation established in an abandoned field in southern Québec (Canada) since 1987. To ascertain the efficiency of mulching materials on the performance of tree seedlings, a herbicide (glyphosate, 6 l ha⁻¹) was applied in half of the experimental plots in June 1990 and 1991. Soil parameters (temperature, moisture) and soil nitrate and ammonium concentrations were measured during the growing season in 1991. In summer 1991, nitrogen nutrition of the seedlings was monitored using enzyme assays (nitrate reductase activity (NRA), glutamine synthetase activity (GSA)) of the leaves of the three deciduous tree species. Mulching affected soil parameters, with black plastic producing the highest soil temperature (23.4°C) and straw the highest soil moisture (183.6 g kg⁻¹) in June. NRA varied in relation to tree species, herbicide application, mulching material and time. GSA was poorly correlated to silvicultural treatments. Butternut showed the highest NRA, especially in herbicide plots irrespective of mulching material. Bur oak NRA showed less variation between herbicide and non-herbicide plots and reacted more to the mulching treatments. White ash NRA only showed an herbicide effect in June. All species reacted positively to the addition of an herbicide around the mulching material, but not to the same degree. Height and diameter increment ratios (with/without glyphosate application) indicate that butternut growth was the most improved by herbicide applications, followed by white ash and bur oak. This indicates that the effectiveness of mulching alone decreases in the following order: bur oak > white ash > butternut. The utilization of mulching material in abandoned fields as an alternative to herbicide application is closely linked to the species chosen. Enzyme assays (NRA) were shown to be a valuable tool for monitoring physiological status of planted trees subjected to environmental changes brought on by silvicultural practices.     

Rhenium-osmium and samarium-neodymium isotopic systematics of the stillwater complex

Isotopic data for the Stillwater Complex, Montana, which formed about 2700 Ma (million years ago), were obtained to evaluate the role of magma mixing in the formation of strategic platinum-group element (PGE) ore deposits. Neodymium and osmium isotopic data indicate that the intrusion formed from at least two geochemically distinct magmas. Ultramafic affinity (U-type) magmas had initial epsilon(Nd) of -0.8 to -3.2 and a chondritic initial (187)Os/(186)Os ratio of approximately 0.88, whereas anorthositic affinity (A-type) magmas had epsilon(Nd) of -0.7 to +1.7 and an initial (187)Os/(186)Os ratio of approximately -1.13. These data suggest that U-type magmas were derived from a lithospheric mantle source containing recycled crustal materials whereas A-type magmas originated either by crustal contamination of basaltic magmas or by partial melting of basalt in the lower crust. The Nd and Os isotopic data also suggest that Os, and probably the other PGEs in ore horizons such as the J-M Reef, was derived from A-type magmas. The Nd and Os isotopic heterogeneity observed in rocks below the J-M Reef also suggests that A-type magmas were injected into the Stillwater U-type magma chamber at several stages during the development of the Ultramafic series.     

Inhibition of key digestive enzymes by cocoa extracts and procyanidins

This study determined the in vitro inhibitory effects of cocoa extracts and procyanidins against pancreatic α-amylase (PA), pancreatic lipase (PL), and secreted phospholipase A(2) (PLA(2)) and characterized the kinetics of such inhibition. Lavado, regular, and Dutch-processed cocoa extracts as well as cocoa procyanidins (degree of polymerization (DP) = 2-10) were examined. Cocoa extracts and procyanidins dose-dependently inhibited PA, PL, and PLA(2). Lavado cocoa extract was the most potent inhibitor (IC(50) = 8.5-47 μg/mL). An inverse correlation between log IC(50) and DP (R(2) > 0.93) was observed. Kinetic analysis suggested that regular cocoa extract, the pentamer, and decamer inhibited PL activity in a mixed mode. The pentamer and decamer noncompetitively inhibited PLA(2) activity, whereas regular cocoa extract inhibited PLA(2) competitively. This study demonstrates that cocoa polyphenols can inhibit digestive enzymes in vitro and may, in conjunction with a low-calorie diet, play a role in body weight management.     

Intranuclear localization of mercury in vivo

Purified nuclei isolated from mice challenged with nonlethal levels of mercury chloride (10-(3)M) in drinking water for 4 to 7 weeks (experimental) and from animals given deionized water (control) were fractionated and the subsequent fractions were analyzed for mercury by flameless atomic absorption. Control (active) euchromatin contained 1.75 +/- 0.53 micrograms of mercury per milligram of DNA. There was a 12- to 15-fold enrichment of mercury in the euchromatin fraction of challenged animals. Mercury was not detected in control (inactive) heterochromatin, and only trace levels (parts per billion) appeared in experimental heterochromatin. It seems likely that mercury can be incorporated into chromatin as a metal-protein complex, but the possibility of protein-mercury-DNA or mercury-DNA complexes within euchromatin cannot be excluded.