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Background and Purpose Nasal sensory nerves play an important role in symptoms associated with rhinitis triggered by environmental stimuli. Here, we propose that TRPV1 is pivotal in nasal sensory nerve activation and assess the potential of SB-705498 as an intranasal therapy for rhinitis. Experimental Approach The inhibitory effect of SB-705498 on capsaicin-induced currents in guinea pig trigeminal ganglion cells innervating nasal mucosa was investigated using patch clamp electrophysiology. A guinea pig model of rhinitis was developed using intranasal challenge of capsaicin and hypertonic saline to elicit nasal secretory parasympathetic reflex responses, quantified using MRI. The inhibitory effect of SB-705498, duration of action and potency comparing oral versus intranasal route of administration were examined. Key Results SB-705498 concentration-dependently inhibited capsaicin-induced currents in isolated trigeminal ganglion cells (pIC50 7.2). In vivo, capsaicin ipsilateral nasal challenge (0.03–1 mM) elicited concentration-dependent increases in contralateral intranasal fluid secretion. Ten per cent hypertonic saline initiated a similar response. Atropine inhibited responses to either challenge. SB-705498 inhibited capsaicin-induced responses by ∼50% at 10 mg·kg−1 (oral), non-micronized 10 mg·mL−1 or 1 mg·mL−1 micronized SB-705498 (intranasal) suspension. Ten milligram per millilitre intranasal SB-705498, dosed 24 h prior to capsaicin challenge produced a 52% reduction in secretory response. SB-705498 (10 mg·mL−1, intranasal) inhibited 10% hypertonic saline responses by 70%. Conclusions and Implications The paper reports the development of a guinea pig model of rhinitis. SB-705498 inhibits capsaicin-induced trigeminal currents and capsaicin-induced contralateral nasal secretions via oral and intranasal routes; efficacy was optimized using particle-reduced SB-705498. We propose that TRPV1 is pivotal in initiating symptoms of rhinitis. more...

Aim: This study aimed to chart the time course and durability of the effects of rosiglitazone, a potent thiazolidinedione-based peroxisome proliferator-activated receptor γ agonist, on hepatic steatosis and intramyocellular lipid in an animal model of obesity, the Zucker Fatty (ZF) rat. Methods and Results: Rosiglitazone (3 mg/kg/day p.o.) significantly reduced both liver fat content (by 59%; p more...

Aim: To characterize evolution and distribution of abdominal adipose fat between 6 and 18 weeks of age in an animal model of energy consumption based on mice overexpressing the mitochondrial uncoupler protein 3 (UCP-3). Methods: T2-weighted multislice MRI was performed six times during the 12 week study; visceral, subcutaneous and intermuscular fat depots were quantified. Results: The overexpressor (UCP-3tg) mice consistently have less subcutaneous, visceral, interskeletal muscle and total fat throughout the experiment. Mean (standard error) volumes (ml) of the three distinct depots change between week 6 and week 18 as follows: wild type: subcutaneous 1.93 (0.28) to 6.18 (0.47), visceral 2.15 (0.34) to 6.37 (0.64), intermuscular 0.23 (0.04) to 0.53 (0.03); UCP-3tg: subcutaneous 1.47 (0.17) to 4.07 (0.57), visceral 1.18 (0.04) to 3.69 (0.59), intermuscular 0.23 (0.01) to 0.32 (0.04). Although they eat more (4.3 g compared with 3.4 g per day) the UCP-3tg's always weigh less than controls. In wild-type control animals, increases of all fat pools between week 6 and week 18 is highly significant, as it is for subcutaneous, visceral and total pools in the UCP-3tg animals. The UCP-3tg mice, however, show no significant absolute or relative increase in intermuscular fat; UCP-3 is predominantly overexpressed in skeletal muscle. Conclusion: MRI provides an excellent approach to comparative studies of fat distribution in animal models of energy expenditure such as the UCP-3tg mouse. more...

A technique is described to perform magnetic resonance spectroscopy (MRS) studies at hypothermia on human donor livers in a prospective fashion in the time interval between organ flushing and subse... more...

Uncoupling protein-3 (UCP-3) is a recently identified member of the mitochondrial transporter superfamily that is expressed predominantly in skeletal muscle. However, its close relative UCP-1 is expressed exclusively in brown adipose tissue, a tissue whose main function is fat combustion and thermogenesis. Studies on the expression of UCP-3 in animals and humans in different physiological situations support a role for UCP-3 in energy balance and lipid metabolism. However, direct evidence for these roles is lacking. Here we describe the creation of transgenic mice that overexpress human UCP-3 in skeletal muscle. These mice are hyperphagic but weigh less than their wild-type littermates. Magnetic resonance imaging shows a striking reduction in adipose tissue mass. The mice also exhibit lower fasting plasma glucose and insulin levels and an increased glucose clearance rate. This provides evidence that skeletal muscle UCP-3 has the potential to influence metabolic rate and glucose homeostasis in the whole animal. more...

Background/Aims: In vivo magnetic resonance spectroscopy can be used to study cerebral metabolism non-invasively. We aimed to correlate 1H and 31P magnetic resonance spectral abnormalities in the brains of patients with subclinical hepatic encephalopathy. Methods: Eighteen patients were studied at 1.5T, with combined 1H and 31P magnetic resonance spectra obtained from multiple voxels in the cerebral cortex and basal ganglia. Peak area ratios of choline, glutamine/glutamate, relative to creatine in the 1H spectra and percentage phosphomonoesters, phosphodiesters and ?NTP signals relative to total 31P signals in the 31P spectra were measured. Results: Six patients did not complete the full examination –31P results are available from 12 patients only. Relative to creatine, there were reductions in choline and elevations in glutamine/glutamate, varying across the brain with choline significantly reduced in occipital cortex (p more...

A semi-automated, metabolite prior-knowledge-based, lineshape fitting analysis has been developed to assess the dynamic biochemical changes found in ex vivo31P NMR pig liver preservation studies. Due to the inherent experimental limitations of the ex vivo study and the complexity of the composite phosphorus resonances, metabolite information obtained in vitro was incorporated into the ex vivo analysis. This approach has allowed complete metabolite analysis (phosphomonoesters, inorganic phosphate, phosphodiesters and nucleotide triphosphates) in over 2000 spectra in a fraction of the time compared with more conventional analysis methods. The developed analysis will enable complete and rapid assessment of the biochemical changes in ongoing cold preservation studies of the pig liver which will result in thousands of ex vivo31P NMR spectra. It is also envisaged that comparative studies on human donor livers will be carried out, in which this type of analysis would be the method of choice. Moreover, this kind of analysis approach could be advantageous in many complex in vivo NMR spectroscopy applications. more...

We report the case of an insulin-dependent diabetic with persistent abdominal pain secondary to non-alcohol-related hepatic steatosis which was unrelieved with standard analgesia. The pain responded to regular intravenous infusion of polyunsaturated fatty acids (intralipid 10%). In vivo hepatic magnetic resonance spectroscopy (MRS) and in vitro proton MRS of plasma in the patient and also in three healthy volunteers demonstrated metabolic changes consistent with intralipid induced stimulation of hepatic fatty acid P-oxidation. Pharmacological stimulation of endogenous hepatic fatty acid oxidation as a therapeutic approach in hepatic steatosis is worthy of further investigation. 1998 Elsevier Science Ireland Ltd. All rights reserved. more...

In vivo 13C-NMR was employed to determine the hepatic fate of infused [1-13C]-d-glucose (200 mg/kg) following ad libitum or routine meal feeding (RMF) regimes imposed during pregnancy. Hepatic glycogen synthesis was measured immediately following the last meal in virgin, 10 and 20 day pregnant rats. No detectable incorporation of 13C-glucose into glycogen was observed in 20 day pregnant and control fed virgin rats. In 20 day pregnant RMF rats, glycogen synthesis from 13C-glucose occurred at a linear rate of 0.10/s (S.D. 0.018/s). By 50 min post-infusion, 13C-glycogen levels were 131% (p more...

Quantitative artificial neural network analysis for 1550 ex vivo 31P nuclear magnetic resonance spectra from hypothermically reperfused pig livers was assessed. These spectra show wide ranges of metabolite concentrations and have been analyzed using metabolite prior knowledge based lineshape fitting analysis which had proved robust in its biochemical interpretation. This finding provided a good opportunity to assess the performance of artificial neural network analysis in a biochemically complex situation. The results showed high correlations (0.865or = Ror = 0.992) between the lineshape fitting and artificial neural network analysis for the metabolite values, and the artificial neural network analysis was able to fully represent the trends in the metabolic fluctuations during the experiments. more...

Magnetic resonance spectroscopy (MRS) allows the noninvasive measurement of whole organ metabolism due to the presence of the MR-sensitive nucleus phosphorus 31 in adenosine triphosphate (ATP), its precursors, and break-down products. In small animal liver transplant studies it has been used to analyze the metabolic effects of cold and warm ischemia, hypothermic reperfusion, and the relative efficacy of different organ preservation solutions. In recent large animal studies MRS has been developed to provide continuous dynamic information on ATP metabolism during graft reperfusion and the bioenergetic consequences of altering preservation solutions. These basic experimental data need to be critically evaluated in human liver transplantation. Encouraging preliminary data on many possible clinical applications have already been obtained, such as the assessment of human donor liver viability and posttransplant graft function. At present, the cost and technically demanding nature of MRS may restrict its application to research units. more...

This study set out to validate the use of 31P-NMR spectroscopy together with alanine +/- glucagon infusions to assess hepatic gluconeogenic flux in vivo. Bolus infusions of alanine (2.8 or 5.6 mmol/kg) +/- glucagon (250 microg/kg) were used. Maximal changes in the phosphomonoesters (PME), inorganic phosphate (Pi) and beta-NTP occurred 40 mins post infusion. PME increased 13.1% (p0.02) and 20.8% (P0.01) at 2.8 mmol/kg + glucagon and 5.6 mmol/kg +/- glucagon, respectively. Pi was unaltered at 2.8 mmol/kg but increased by 28.8% (P0.01) at 5.6 mmol/kg alanine + glucagon. beta-NTP decreased by 14.4% (P0.02) and 16.1% (P0.02) at 5.6 mmol/kg -/+ glucagon, respectively. This latter infusion showed slower recovery rates of NTP which remained 12.3% (P0.05) lower 70 min post infusion compared with pre-infusion values. 31 P-NMR analysis of liver extracts revealed that PME increases were partly due to 3-phosphoglycerate and corroborated reductions in beta-NTP and gamma-NTP: beta-NDP ratio upon infusion of 5.6 mmol/kg alanine +/- glucagon. Hepatic glucose output from perfused liver experiments showed no difference between alanine concentrations indicating maximal glucose output at the lower concentration. This study has shown that in vivo 31P-NMR in combination with alanine infusion, can be used to determine metabolic changes associated with gluconeogenesis. more...

We have developed a quick, non-invasive method for measuring the ability of an isolated preserved liver to regenerate high energy phosphate nucleotides without the need for biopsy. Using 31P MRS we have monitored the hepatic energetics of intact cold preserved pig liver using standard clinical harvesting and storage techniques. Following cold storage for 2 h the livers were hypothermically reperfused with oxygenated modified University of Wisconsin preservation fluid. Prior to reperfusion MRS detectable adenosine diphosphate plus adenosine triphosphate was negligible; however, the spectrum showed intense resonances from phosphomonoesters and inorganic phosphate, as a consequence of adenosine triphosphate hydrolysis during cold preservation. Following a 10-min period of hypothermic reperfusion, regeneration of adenosine triphosphate occurred with a concurrent decline in inorganic phosphate and phosphomonoester, both of which are associated with adenosine triphosphate synthesis. The capacity of the liver to regenerate adenosine triphosphate following a 24-h period of cold storage was reduced by approximately 40% (p more...

Renal transplant programmes are seriously limited by the continuing shortage of donor organs. Kidneys from marginal and non-heart-beating donors are increasingly being used, but their viability may be compromised. There is currently no rapid yet accurate method for assessing donor organ viability which can be applied within the window of opportunity between harvesting and implantation. Magnetic resonance spectroscopy (MRS) is a non-invasive technique which is being increasingly applied to delineate biochemical changes in vivo. Studies in animal models and humans now suggest that phosphorus-31 MRS may be useful in the non-invasive assessment of isolated donor kidney viability. more...

Preclinical imaging with magnetic resonance imaging (MRI), computerised tomography (CT), ultrasound (US), positron emission tomography (PET) or single-photon emission computed tomography (SPECT) enable non-invasive measures of tissue structure, function or metabolism in vivo. The technologies can add value to preclinical studies by enabling dynamic pharmacological observations on the same animal and because of possibilities for relatively direct clinical translation. Potential benefits from the application of preclinical imaging should be considered routinely in drug development. more...

The present study investigated the role that imaging could have for assessing lung inflammation in a mouse model of HDM (house dust mite)-provoked allergic inflammation. Inflammation is usually assessed using terminal procedures such as BAL (bronchoalveolar lavage) and histopathology; however, MRI (magnetic resonance imaging) and CT (computed tomography) methods have the potential to allow longitudinal, repeated study of individual animals. Female BALB/c mice were administered daily either saline, or a solution of mixed HDM proteins sufficient to deliver a dose of 12 or 25 μg total HDM protein±budesonide (1 mg/kg of body weight, during weeks 5–7) for 7 weeks. AHR (airway hyper-responsiveness) and IgE measurements were taken on weeks 3, 5 and 7. Following imaging sessions at weeks 3, 5 and 7 lungs were prepared for histology. BAL samples were taken at week 7 and lungs prepared for histology. MRI showed a gradual weekly increase in LTI (lung tissue intensity) in animals treated with HDM compared with control. The 25 μg HDM group showed a continual significant increase in LTI between weeks 3 and 7, the 12 μg HDM-treated group showed a similar rate of increase, and plateaued by week 5. A corresponding increase in AHR, cell counts and IgE were observed. CT showed significant increases in lung tissue density from week 1 of HDM exposure and this was maintained throughout the 7 weeks. Budesonide treatment reversed the increase in tissue density. MRI and CT therefore provide non-invasive sensitive methods for longitudinally assessing lung inflammation. Lung tissue changes could be compared directly with the classical functional and inflammatory readouts, allowing more accurate assessments to be made within each animal and providing a clinically translatable approach. more...

The aim of this study was to assess the possibility of regenerating nucleotide triphosphates (NTP) in the pig liver following its harvest and subsequent storage on ice. This study has used a pig model that allowed human donor liver retrieval techniques and methods of storage to be utilized. In vitro phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy was used to evaluate the changes associated with phosphorus containing metabolites such as NTP, phosphomonoesters (PME), phosphodiesters (PDE), and inorganic phosphate (Po). During 4 hr storage NTP levels were reduced to undetectable levels but its regeneration was possible over a period of 2 hr of oxygenated hypothermic reperfusion. Resynthesized NTP reached values that were only 30% reduced from pre-harvest values. There was a corresponding reduction in Pi over the same period. Glycolytic intermediates, 3-phosphoglycerate and 2,3 diphosphoglycerate, both increased significantly during the period of storage and subsequently declined following hypothermic reperfusion. Cellular damage, indicated by the concentrations of glycerophosphorylcholine (GPC) and glycerophosphorylethanolamine (GPE) was minimal during cold storage. However upon hypothermic reperfusion, concentrations of GPC and GPE reduced, indicating a degree of cellular damage caused by reperfusion. This study has shown for the first time that is possible to regenerate high energy phosphate nucleotides following a period of hypothermic reperfusion in a large, clinically related animal model. This technique warrants investigation clinically to improve the outcome of orthotopic liver transplantation. It also provides a method to study the effects of different preservation fluids and methods of storage and organ reperfusion. more...

Glucose utilization indices (GUIs) were measured in heart and a range of skeletal muscles in conscious, unrestrained, virgin or pregnant rats in the absorptive and post-absorptive phases. A clear effect of pregnancy to diminish muscle GUIs was identified, the magnitude of which was greatest in late gestation in the absorptive phase. Differences in the time courses and magnitudes of the response to pregnancy were observed between individual muscles. The effects of pregnancy are discussed in relation to an increased availability of lipid fuels and to decreased insulin and glucose concentrations. more...

Recent innovations in drug therapies have made it highly desirable to obtain sensitive biomarkers of disease progression that can be used to quantify the performance of candidate disease modifying drugs. In order to measure potential image-based biomarkers of disease progression in an experimental model of rheumatoid arthritis (RA), we present two different methods to automatically quantify changes in a bone in in-vivo serial magnetic resonance (MR) images from the model. Both methods are based on rigid and nonrigid image registration to perform the analysis. The first method uses segmentation propagation to delineate a bone from the serial MR images giving a global measure of temporal changes in bone volume. The second method uses rigid body registration to determine intensity change within a bone, and then maps these into a reference coordinate system using nonrigid registration. This gives a local measure of temporal changes in bone lesion volume. We detected significant temporal changes in local bone lesion volume in five out of eight identified candidate bone lesion regions, and significant difference in local bone lesion volume between male and female subjects in three out of eight candidate bone lesion regions. But the global bone volume was found to be fluctuating over time. Finally, we compare our findings with histology of the subjects and the manual segmentation of bone lesions. more...

Thymus involution is a useful marker of transactivation-mediated side effects in preclinical therapeutic index testing of new anti-inflammatory glucocorticosteroids, and is usually measured post mortem . We have validated the use of MRI for non-invasive in vivo measurement of mouse thymus involution induced by dexamethasone (DEX). Tl-weighted spin echo 7 T images provided satisfactory contrast between thymus and surrounding connective tissue and fat. Increasing doses of DEX caused thymus involution, reflected in MRI volume (87 ± 14, 33 ± 10, 28 ± 6, 16 ± 7 μl in dosage groups of Cremophor vehicle, 1, 10 and 30 mg/kg subcutaneous respectively, n = 6/group, mean ± standard deviation) and post mortem wet weight (64 ± 12, 33 ± 6, 25 ± 9, 23 ± 8 mg). Correlation between MRI volumes and wet weights was very good ( r = 0.842). Measuring pre-dose MRI volumes and then assessing DEX effects as post-dose change from baseline produced no statistical advantage relative to considering post-dose MRI thymus volume alone, probably due to variability in pre-dose baseline values compounding post-dose variability. Smaller group sizes were sufficient to achieve a given statistical power using MRI post-dose volume than using wet weight, suggesting a role for MRI in differentiating the effects of compounds which produce similar effects, or in contexts where the use of large groups of animals is impractical or ethically unacceptable. more...

BACKGROUND AND AIMS—Alterations in gluconeogenesis in the diseased liver can be assessed non-invasively using magnetic resonance spectroscopy by measuring changes in phosphomonoester resonance which contains information regarding several metabolites, including the phosphorylated intermediates of the gluconeogenic pathway. METHODS—31P magnetic resonance spectroscopy was used to determine changes in phosphomonoesters following bolus infusions of 2.8 mmol/kg L-alanine in five patients with functionally compensated cirrhosis and in five patients with functionally decompensated cirrhosis. RESULTS—Compared with six healthy volunteers, baseline phosphomonoester values were elevated by 35% (p more...

During liver preservation, ATP supplies become depleted, leading to loss of cellular homeostatic controls and a cascade of ensuing harmful changes. Anaerobic glycolysis is unable to prolong ATP production for a significant period because of metabolic blockade. Our aim was to promote glycolysis during liver cold hypoxia by supplying fructose as an additional substrate, compared to supplementation with an equivalent concentration of glucose. Porcine livers (two groups; n = 5 in each) were retrieved by clinical harvesting techniques and subjected to two cycles of cold hypoxia and oxygenated hypothermic reperfusion. In the second cycle of reperfusion, the perfusate was supplemented with either 10 mmol/L glucose (Group 1) or 10 mmol/L fructose (Group 2). During reperfusion in both groups, similar levels of ATP were detected by phosphorus magnetic resonance spectroscopy ((31)P MRS). However, during subsequent hypoxia, ATP was detected for much longer periods in the fructose-perfused group. The rate of ATP loss was sevenfold slower during hypoxia in the presence of fructose than in the presence of glucose (ATP consumption of -7.2 x 10(-3)% total (31)P for Group 1 versus -1.0 x 10(-3)% total (31)P for Group 2; P0. 001). The changes in ATP were mirrored by differences in other MRS-detectable intermediates; e.g., inorganic phosphate was significantly higher during subsequent hypoxia in Group 1 (45.7 +/- 2.7% total (31)P) than in Group 2 (33.7 +/- 1.1% total (31)P; P0. 01). High-resolution MRS of liver tissue extracts demonstrated that fructose was metabolized mainly via fructose 1-phosphate. We conclude that fructose supplied by brief hypothermic perfusion may improve the bioenergetic status of cold hypoxic livers by sustaining anaerobic glycolysis via a point of entry into the pathway that is different from that for glucose. more...

Magnetic resonance imaging (MRI) has given inconsistent results when used as a non-invasive diagnostic tool for Creutzfeldt–Jakob disease (CJD). In order to understand this finding, we studied a hamster model of scrapie by in vivo MRI and histopathology. Vacuolation of neurones/neuropil and gliosis were found to correlate with hypo-intense and hyper-intense changes in the conventional T2-weighted MR images, respectively. These opposing effects were shown to give rise to normal images of a scrapie-affected brain undergoing severe neurodegeneration, and may underlie the variability of previous CJD MRI data. more...

The use of nuclei other than 1 H or 31 P for in vivo applications of NMR spectroscopy is surveyed. The principal nuclei studied are 13 C and 19 F, but applications involving 15 N, 23 Na, 7 Li, and other less widely employed nuclei are also included. more...

Background—In vivo hepatic phosphorus-31 magnetic resonance spectroscopy (MRS) provides non-invasive information about phospholipid metabolism.Aims—To delineate MRS abnormalities in patients with chronic ductopenic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy.Patients and methods—Sixteen liver transplant recipients (four with CDR; 12 with good graft function) and 29 controls (23 healthy volunteers; six patients with biliary duct strictures) were studied with in vivo 31P MRS. Peak area ratios of phosphomonoesters (PME) and phosphodiesters (PDE), relative to nucleotide triphosphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze clamped at retransplantation. Phosphoethanolamine (PE), phosphocholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured.Results—The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four patients with CDR showed significantly elevated PME:NTP (pConclusions—The increase in PME:NTP reflects altered phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipid. more...

In vivo 31P magnetic resonance spectroscopy (MRS) provides direct biochemical information on hepatic metabolic processes. To assess in vivo changes in hepatic 31P MRS in liver transplant candidates, we studied 31 patients with cirrhosis of varying aetiology; 14 with compensated cirrhosis (Pugh's scoreor = 7) and 17 with decompensated cirrhosis (Pugh's scoreor = 8). Underlying cellular abnormalities were characterised using in vitro 31P MRS and electron microscopy. In vitro spectra were obtained from liver extracts, freeze-clamped at recipient hepatectomy, from all subjects. Electron microscopy of liver tissue was also performed in 17 cases. Relative to nucleotide triphosphates, elevations in phosphomonoesters and reductions in phosphodiesters were observed in vivo with worsening liver function. In vitro spectra showed elevated phosphoethanolamine and phosphocholine, and reduced glycerophosphorylethanolamine and glycerophosphorylcholine, mirroring the in vivo changes, but no distinction was noted between compensated and decompensated cirrhosis. With electron microscopy, functional decompensation was associated with reduced endoplasmic reticulum in parenchymal liver disease, but elevated levels in biliary cirrhosis. We conclude that in vivo spectral abnormalities in cirrhosis are consistent with alterations in phospholipid metabolism and quantity of endoplasmic reticulum. However, in individual patients the biopsy results do not always mirror in vivo findings. more...

The present study investigated the role that imaging could have for assessing lung inflammation in a mouse model of a house dust mite (HDM) provoked allergic inflammation. Inflammation is usually assessed using terminal procedures such as bronchoalveolar lavage (BAL) and histopathology; however, magnetic resonance imaging (MRI) and computed tomography (CT) methods have the potential to allow longitudinal, repeated study of individual animals. Female BALB/c mice were administered daily either saline, or a solution of mixed HDM proteins sufficient to deliver a dose of 12µg or 25µg total HDM protein ± budesonide (1mg/kg, during weeks 5-7) for 7 weeks. Airway hyper- responsiveness (AHR) and IgE measurements were taken on weeks 3, 5 and 7. Following the last imaging session BALs were taken and lungs prepared for histology. MRI showed a gradual weekly increase in lung tissue intensity (LTI) in animals treated with HDM compared to control. The 25ug HDM group showed a continual significant increase in LTI between weeks 3-7, the 12ug HDM treated group showed similar rates of increase, and plateaued by week 5 (Figure ​(Figure1).1). A corresponding increase in AHR, cell counts and IgE were observed. CT showed significant increases in lung tissue density from week 1 of HDM and this was maintained throughout the 7 weeks. Budesonide treatment reversed the increase in tissue density (Figure ​(Figure2).2). MRI and CT therefore provide non-invasive sensitive methods for longitudinally assessing lung inflammation. Lung tissue changes could be compared directly with the classical functional and inflammatory readouts allowing more accurate assessments to be made within each animal and provide a clinically translatable approach. Figure 1 MRI data Figure 2 CT data more...

Short term starvation is associated with a depletion in hepatic glycogen stores which are quickly replenished within 6-7 hours [ 11 upon refeeding. Glucose levels during short term starvation are maintained primarily from glycogenolysis (75%) and to a lesser extent from gluconeogenesis (25%) [2] using lactate, alanine and glycerol as the major precursors for this process. When rats are meal-fed, carbohydrate and lipid metabolism undergo some profound changes contrary to normal short term starvation patterns. Pallardo and Williamson [3] showed that when rats are placed on a routine meal feeding regime for 10 days hepatic lipid synthesis rates were vastly increased. However, similar hepatic glycogen deposition rates to ad libitum fed rats prevailed. We have been investigating the use of I3C-NMR spectroscopy to study the disposal of l-13C glucose in the liver. 13C-NMR spectroscopy has been used to study glycogen synthesis in muscle and liver and also to gain information on gluconeogenic rates in rats and man [4]. Using proton-decoupled 13C-NMR spectroscopy it is possible to observe in vivo changes in l-13C glucose levels and 13C-l incorporation into the glycogen macromolecule. We have investigated the hepatic carbohydrate status of 4 week meal-fed rats prior and post feeding after a bolus infusion of glucose. Ten age-matched female Wistar rats (1 85-2000) were housed in a reverse light/dark room [light off 10:00fight on 22:00] and allowed access to a standard chow diet for 2 hours per day for 4 weeks [10:00 to 12:00]. The experiments were c d e d out over a period of 5 days where two rats per day were experimented on for pre (23 hour starved) and post meal (1 hour after the end of feeding) hepatic glucose/glycogen metabolism. The rats were anaesthetised with 60mglmVkg sodium pentobarbital and a blood sample removed from the jugular vein. The hepatic portal vein was cannulated and attached to a line containing D-glu~osel -~~C (99atom % I3C) [2oOmg/ml; 250mglkgl. A dual-tunedproton/carbon surface coil was positioned directly onto the liver and the animal placed in the bore of the magnet. Proton-decoupled carbon13 spectra were obtained at 50.309MHz using a 4.7 Tesla, 33cm horizontal bore system, an acquisition time of 0.205s, a relaxation time of O.ls, a pulse width of 70ps and a spectral width of 12kHz. Twenty-five array elements consisting of 512 averages over a period of 65 mins were collected (ie 1 spectra=2.6 mins. to acquire). Two base-line spectra were collected prior to the infusion of the 13C-glucose [75mg;20mg/min]. Subsequent to infusion of the "C-glucose,the spectra obtained were referenced to C-l,O glucose at 96.60ppm and C-1 glycogen appearance observed at 100.48ppm. Quantification of the glucose and glycogen involved the integration of the respective resonances in each spectrum and standardised to the -CH#CH, integrated region [5]. Figure I shows typical carbon spectra prior to glucose infusion and 30 mins. post infusion, with the evolution of glycogen clearly visible at 100.48ppm. It can also be seen that the hepatic 13Cglucose disposal in the two groups are very similar, however, the post meal decay is faster. Glycogen 13C incorporation rate in the pre-meal group is shown to rise linearly for 30 minutes post glucose infusion. The rate was considerably faster than that in rats either fed ad libitum or starved [5 and unpublished]. The post meal group shows little net incorporation of 13C-glucose into glycogen implying that either maximal glycogen levels had been reached or synthesis was occumng preferentially from the unlabelled pool of 3 and 4 carbon precursors generated during refeeding. With food FIG 1 more...

Pregnancy places many demands on the mother both physiologically and metabolically. The mother must sustain nument balance to both herself and the developing fetus(es). As a consequence, late pregnancy is associated with insulin resistance [ 13 and glucose intolerance together with increased lipid and ketone body circulation and utilization by a wide range of tissue types [2]. It is thought that these and other metabolic changes ensure channeling of the blood glucose to the uterine system, suggesting that glucose is a preferred fuel substrate for the conceptus, possibly due to the ease of mobilization and transport of glucose, or glucose oxidation processes being the better developed. The liver controls glucose homeostasis, therefore for increased knowledge of the pathogenesis of insulin resistant states, studies of the kinetics of hepatic glucose disposal are necessary. In this study proton-decoupled carbon13 magnetic resonance spectroscopy (MRS) has been employed as a tool for in vivo hepatic measurements to elucidate the liver's glucose utilizatioddisposal capacity during pregnancy. Two groups of age-matched female albino Wistar rats were time-mated. One group was allowed food ad libitum [Group I] whereas Group I1 (routinely meal fed-RMF [3]) were transferred to a reverse lighvdark mom [light off 10:00/light on 22:00] and allowed access to chow for 2hr/day from day 5 of pregnancy. Group ID were age-matched virgin controls fed ad libitum. Immediately after the last meal on day 20 of gestation (term=21), the rat was anaesthetized with sodium pentobarbital. The liver was exposed and the hepatic portal vein cannulated to a line containing D-glucose-l-'3C(99atom % I3C) [2OOmg/ml]. A dual-tuned protodcarbon coil was placed directly on top of the liver and the animal placed into the bore of the magnet. Using a 4.7 Tesla, 33cm horizontal bore imaging spectrometer, proton-decoupled carbon spectra were acquired at 50.309MHz with an acquisition time of 0.205s, relaxation time of O.ls, a pulse width of 70ps and spectral width of 12kHz. Spectra were accumulated every 2.5min over a 65min period. After accumulation of two base-line spectra, D-glucose1'3C[75mg;30mg.min-'] was infused. Spectra were referenced to C-1, I3 glucose at 96.60ppm. The C-1 glycogen resonance at 100.48ppm was evaluated. Glucose disposal and glycogen synthesis rates were assessed from the relative peak areas normalized to the -CH, integrated area which, from lipid extraction studies, remains constant in the fed groups. From Fig. I , very little incorporation of "C-glucose into glycogen was detected in Groups I and 111, whereas Group I1 had a much enhanced incorporation rate, in an approximately linear fashion. Glucose profiles of the three groups indicate relatively slow removal of glucose from the splanchnic region in Groups 11 and 111 in contrast to Group I. Late pregnancy is shown to diminish intracellular glucose utilization by the liver, reflected in the lack of glucose assimilation and utilization compared with the same fed virgin condition whereas by routine meal feeding, enhanced glucose uptake and incorporation into glycogen can be seen in gestationally the same condition. This study suggests an important change in glucose homeostasis by the liver during pregnancy and the importance of MRS for investigating in vivo glucose kinetics. C 1 C 2C 30 40 50 60 more...