Investigation of the Confinement Odour Problem in Exported Lamb using NMR-based Metabolomics : A thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University, Manawatū, New Zealand.

Recent changes to the supply chain practices of meat exporters has increased the potential for consumers to be exposed to the phenomenon of confinement odour, the smell produced by vacuum or modified atmosphere packaged meat which has been chilled and stored for extended periods. This harmless odour, which does not indicate meat spoilage, can lead to the rejection of the product by consumers. This is a problem for NZ lamb meat producers as they form the largest group of exporters of lamb meat in the world, and their largest market is the UK and other EU countries. The processes behind confinement odour development are poorly understood. In this thesis, NMR spectra were acquired of meat, and drip extracts of meat from two different processing plants stored under different temperatures for 11-13 weeks to simulate conditions of exported meat during overseas shipment, transport to warehouse and retail display. The spectra were analysed by multivariate data analysis to find metabolic differences between meat which produces confinement odour and meat which produces either spoilage odour or no odour. Optimisation of extraction of metabolites from meat and drip samples was also carried out. The best sample preparation method for meat and drip included homogenisation by bead beating (meat samples only), protein precipitation using an acetonitrile, methanol and acetone solvent mixture, and removal of solvent by vacuum centrifugation. Multivariate data analysis demonstrated the ability to discriminate drip samples with confinement odour from spoiled samples and the former showed increased lactate concentration with low levels of leucine indicating the presence of Lactic Acid bacteria. The spoiled samples had increased butyrate levels which is indicative of the presence of Clostridium spp. Both bacterial populations were in a late stage of growth. This is consistent with confinement odour as an early indicator of spoilage. This result indicates the potential for drip to be utilised more widely for the analysis of meat metabolites. Additionally, samples could be discriminated by processing plant of origin using multivariate data analysis. Increased levels of pyruvate and decreased levels of glucose in samples from Plant 2 indicated their bacterial populations had progressed to a later stage of growth than the bacterial populations in samples from Plant 1

The two levels of natural law thinking

Central parts of the natural law theories of Grotius and Pufendorf assume that persons by nature have individual realms of their own (suum), violations of which constitute a wrong. This is the basis for their accounts of promises, ownership and reactions against wrongs. These accounts are significantly independent of any assumption that a superior being imposes obligations: rather, the individuals themselves create obligations by their own acts of will. The translator's introducton draws attention to the author's relation to Hägerström, and remarks briefly on related points in Ames, Köhler and Georges Dav

Extracellular degradation of lipoprotein lipase in rat adipose tissue

BACKGROUND: Recent studies in vivo indicate that short-term regulation of lipoprotein lipase (LPL) in rat adipose tissue is post-translational and occurs by a shift of the lipase protein towards an inactive form under the influence of another gene with short-lived message and product. It has not been possible to reproduce this process with isolated adipocytes suggesting that other cells are needed, and perhaps mediate the regulation. The objective of the present study was, therefore, to explore if explants of adipose tissue could be used for studies of the regulatory process. RESULTS: When explants of rat epididymal adipose tissue were incubated, LPL mass and activity decreased rapidly. Mass and activity within adipocytes remained constant for at least six hours, demonstrating that it was the extracellular portion of the enzyme that decreased. Adipocytes isolated from the explants after three or six hours of incubation retained their ability to secrete LPL to the medium. Addition of a cocktail of protease inhibitors to the incubation medium slowed down the decrease of LPL mass. Chloroquine was without effect, indicating that the degradation was not lysosomal. (125)I-labeled LPL added to the medium was degraded to acid soluble products, indicating that the degradation occurred extracellularly. Fragmentation of the labelled lipase occurred in conditioned medium and this process was virtually abolished by two MMP inhibitors. CONCLUSIONS: The decrease of LPL mass and activity that occurs when explants of rat adipose tissue are incubated is due to proteolysis of extracellular LPL. The adipocytes continue to produce and secrete the enzyme. The effect of inhibitors indicates, but does not prove, that the degradation is mediated by MMPs. It appears that this process is accelerated in the tissue fragments compared to intact tissue

Effects of heparin on the uptake of lipoprotein lipase in rat liver

BACKGROUND: Lipoprotein lipase (LPL) is anchored at the vascular endothelium through interaction with heparan sulfate. It is not known how this enzyme is turned over but it has been suggested that it is slowly released into blood and then taken up and degraded in the liver. Heparin releases the enzyme into the circulating blood. Several lines of evidence indicate that this leads to accelerated flux of LPL to the liver and a temporary depletion of the enzyme in peripheral tissues. RESULTS: Rat livers were found to contain substantial amounts of LPL, most of which was catalytically inactive. After injection of heparin, LPL mass in liver increased for at least an hour. LPL activity also increased, but not in proportion to mass, indicating that the lipase soon lost its activity after being bound/taken up in the liver. To further study the uptake, bovine LPL was labeled with (125)I and injected. Already two min after injection about 33 % of the injected lipase was in the liver where it initially located along sinusoids. With time the immunostaining shifted to the hepatocytes, became granular and then faded, indicating internalization and degradation. When heparin was injected before the lipase, the initial immunostaining along sinusoids was weaker, whereas staining over Kupffer cells was enhanced. When the lipase was converted to inactive before injection, the fraction taken up in the liver increased and the lipase located mainly to the Kupffer cells. CONCLUSIONS: This study shows that there are heparin-insensitive binding sites for LPL on both hepatocytes and Kupffer cells. The latter may be the same sites as those that mediate uptake of inactive LPL. The results support the hypothesis that turnover of endothelial LPL occurs in part by transport to and degradation in the liver, and that this transport is accelerated after injection of heparin

Perception as a Dynamic Activation of Relational Matrices

Here we present an experimental model to be applied to the storage and retrieval of information based on an associative information system’s sensory and motor state change data, aiming to represent the dynamics of a dynamic perceptual system. The model and database implementation use a universal information storage structure holding both data and metadata within the same structure. This model is characterized by the emphasis on associative information about the represented system derived from raw data, which are in their turn produced by the associative system’s interactions with the environment. Instead of defining objects using descriptive relations, this model stores relations between occurents where the represented system is not replicated in its various components, but defined by its relations when they occur. This model therefore represents the dynamics and interaction of systems such as human perception, rather than imposing artificial boundaries and qualities. In essence, the model is an alternative to perceptual knowledge accumulation, which, as we show, can be applied to a database design

Validation of a 3D CT method for measurement of linear wear of acetabular cups: A hip simulator study

Background We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups. Material and methods Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator. Before and after wear, they were (1) imaged with a CT scanner using a phantom model device, (2) measured using a coordinate measurement machine (CMM), and (3) weighed. CMM was used as the reference method for measurement of femoral head penetration into the cup and for comparison with CT, and gravimetric measurements were used as a reference for both CT and CMM. Femoral head penetration and wear vector angle were studied. The head diameters were also measured with both CMM and CT. The repeatability of the method proposed was evaluated with two repeated measurements using different positions of the phantom in the CT scanner. Results The accuracy of the 3D CT method for evaluation of linear wear was 0.51 mm and the repeatability was 0.39 mm. Repeatability for wear vector angle was 17?. Interpretation This study of metal-meshed hip-simulated acetabular cups shows that CT has the capacity for reliable measurement of linear wear of acetabular cups at a clinically relevant level of accuracy

Maternal obesity is associated with the formation of small dense LDL and hypoadiponectinemia in the third trimester

Context: Maternal obesity is associated with high plasma triglyceride, poor vascular function, and an increased risk for pregnancy complications. In normal-weight pregnant women, higher triglyceride is associated with increased small, dense low-density lipoprotein (LDL). Hypothesis: In obese pregnancy, increased plasma triglyceride concentrations result in triglyceride enrichment of very low-density lipoprotein-1 particles and formation of small dense LDL via lipoprotein lipase. Design: Women (n = 55) of body mass index of 18–46 kg/m2 were sampled longitudinally at 12, 26, and 35 weeks' gestation and 4 months postnatally. Setting: Women were recruited at hospital antenatal appointments, and study visits were in a clinical research suite. Outcome Measures: Plasma concentrations of lipids, triglyceride-rich lipoproteins, lipoprotein lipase mass, estradiol, steroid hormone binding globulin, insulin, glucose, leptin, and adiponectin were determined. Results: Obese women commenced pregnancy with higher plasma triglyceride, reached the same maximum, and then returned to higher postnatal levels than normal-weight women. Estradiol response to pregnancy (trimester 1–3 incremental area under the curve) was positively associated with plasma triglyceride response (r2 adjusted 25%, P < .001). In the third trimester, the proportion of small, dense LDL was 2-fold higher in obese women than normal-weight women [mean (SD) 40.7 (18.8) vs 21.9 (10.9)%, P = .014], and 35% of obese, 14% of overweight, and none of the normal-weight women displayed an atherogenic LDL subfraction phenotype. The small, dense LDL mass response to pregnancy was inversely associated with adiponectin response (17%, P = .013). Conclusions: Maternal obesity is associated with an atherogenic LDL subfraction phenotype and may provide a mechanistic link to poor vascular function and adverse pregnancy outcome