Comparison of LC-ESI, DART, and ASAP for the analysis of oligomers migration from biopolymer food packaging materials in food (simulants).

Biopolymers based on polylactic acid (PLA) and starch have numerous advantages, such as coming from renewable sources or being compostable, though they can have deficiencies in mechanical properties, and for this reason, polyester resins are occasionally added to them in order to improve their properties. In this work, migration from a PLA sample and from another starch-based biopolymer to three different food simulants was studied. Attention was focused on the determination of oligomers. The analysis was first performed by ultraperformance liquid chromatography quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS), which allowed the identification of the oligomers present in migration. Then, the samples were analyzed by two ambient desorption/ionization techniques directly coupled to mass spectrometry (ADI), direct analysis in real-time coupled to standardized voltage and pressure (DART-MS) and atmospheric pressure solids analysis probe (ASAP-MS). These methodologies were able to detect simultaneously the main oligomers migrants and their adducts in a very rapid and effective way. Nineteen different polyester oligomers, fourteen linear and five cyclic, composed of different combinations of adipic acid [AA], propylene glycol [PG], dipropylene glycol [DPG], 2,2-dibutyl-1,3-propanediol [DBPG], or isobutanol [i-BuOH] were detected in migration samples from PLA. In migration samples from starch-based biopolymer, fourteen oligomers from poly(butylene adipate co-terephthalate) polyester (PBAT) were identified, twelve cyclic and two linear. The results from ADI techniques showed that they are a very promising alternative tool to assess the safety and legal compliance of food packaging materials.

Endovascular management of the deep venous thrombosis: A new challenging role for the endovascular specialist in 2020.

Over the last years, the endovascular approach to the management of the acute and chronic deep vein thrombosis (DVT) has gained more and more attention from the scientific community. DVT is the third most common cardiovascular disease after coronary heart disease and stroke, with classic treatment based on anticoagulation. Recent evidences have highlighted the risk of postthrombotic syndrome as high as 30%-50% in proximal ilio-femoral lesions, with irreversible clinical symptoms and impact on the quality of life of the population. Since 2000s, the new concept of thrombus removal in the acute phase has been supported by the introduction of different techniques based on the endovascular ablation of the clot by in-situ fibrinolysis and, more recently, fragmentation and aspiration. In the chronic phase, recanalization of the thrombosed segment is recommended by stent placement to remove the obstruction and eventually reduce the congestion. Immediate technical success of these procedures is widely satisfying, whereas the long-term clinical benefits are still debated. This paper presents an overview of the modern management of the DVT by endovascular approach with regard to the clinical contexts, interventional strategies and clinical outcomes. Endovascular specialist needs to be aware of this incoming challenge, as local expertise is demanded for the modern management of these patients in multidisciplinary theaters.

Ten-year experience with arterial embolization for peptic ulcer bleeding: N-butyl cyanoacrylate glue versus other embolic agents.

OBJECTIVES: To compare our experience with N-butyl cyanoacrylate glue as the primary embolic agent versus other embolic agents for transcatheter arterial embolization (TAE) in refractory peptic ulcer bleeding and to identify factors associated with early rebleeding and 30-day mortality. METHODS: Retrospective study of 148 consecutive patients comparing the clinical success rate in 78 patients managed with Glubran®2 N-butyl cyanoacrylate metacryloxysulfolane (NBCA-MS) alone or with other agents and 70 with other embolic agents only (coils, microspheres, ethylene-vinyl alcohol copolymer, or gelatin sponge) at a university center in 2008-2019. Univariate and multivariate logistic regression analyses were done to identify prognostic factors. RESULTS: The technical success rate was 95.3% and the primary clinical success was 64.5%. The early rebleeding and day-30 mortality rates were 35.4% and 21.3%, respectively. Rebleeding was significantly less common with than without Glubran®2 (OR, 0.47; 95% CI, 0.22-0.99; p = .047) and significantly more common with coils used alone (OR, 20.4; 95% CI, 10.13-50.14; p = .024). The only other factor independently associated with early rebleeding was having two or more comorbidities (OR, 20.14; 95% CI, 10.01-40.52; p = .047). Day-30 mortality was similar in the two treatment groups. A lower initial hemoglobin level was significantly associated with higher day-30 mortality (OR, 10.38; 95% CI, 10.10-10.74; p = .006). Fluoroscopy time was significantly shorter with Glubran®2 (20.8 ± 11.5 min vs. 35.5 ± 23.4 min, p = .002). Both groups (Glubran®2 vs. other agents) had similar rates of overall complications (10.7% vs. 9.1%, respectively, p = .786). CONCLUSIONS: Glubran®2 NBCA-MS as the primary agent allowed for faster and better clinical success compared to other embolic agents when used for TAE to safely stop refractory peptic ulcer bleeding. KEY POINTS: • Choice of embolic agent for arterial embolization of refractory peptic ulcer bleeding is still debated. We compared our experience with N-butyl cyanoacrylate (NBCA) glue vs. other embolic agents. • The use of Glubran®2 NBCA glue in the endovascular management of refractory peptic ulcer bleeding was significantly faster and more effective, and at least as safe compared to other embolic agents. • NBCA glue offers several advantages compared to other embolic agents and provides rapid hemostasis when used for arterial embolization to treat refractory peptic ulcer bleeding. It should be the first-line therapy.

Safety and Efficacy of Peripheral Embolization with EASYX Liquid Embolic Agent: A Multicenter Prospective Study.

PURPOSE: To evaluate the clinical safety and efficacy of EASYX, a new nonadhesive precipitating liquid embolic agent based on a polyvinyl alcohol ether polymer labeled with iodine molecules, for peripheral embolization. MATERIALS AND METHODS: This open-label prospective multicenter study was conducted on 50 consecutive patients treated with embolization using EASYX in 3 academic hospitals from April 2018 to July 2019. Indications for embolization were symptomatic varicocele (n = 15), type II endoleak (n = 8), acute hemorrhage (n = 16), portal vein embolization (PVE; n = 9), or angiomyolipoma (AML; n = 2). Patient characteristics, technical and clinical success rates, pain at injection, and satisfaction of the interventional radiologists were assessed. Follow-up imaging was performed using ultrasound for varicoceles (at 1 month) and computed tomography (CT) for the other indications (at 3 or 6 months). RESULTS: The immediate technical success rate was 98%. The clinical success rates were 100% for acute hemorrhage and type II endoleaks, 89% for PVE, 86% for varicoceles, and 50% for AMLs. Patients who underwent PVE showed significant hypertrophy of the future liver remnant at follow-up (P < .001), and 55.6% of patients proceeded to hepatectomy. The absence of artifacts on imaging allowed improved monitoring of the aneurysmal sac in patients with type II endoleaks. The satisfaction rate of the interventional radiologists was >90% for 5 of 7 items. CONCLUSIONS: EASYX as a novel copolymer liquid embolic agent was safe and efficient for peripheral embolization. The absence of tantalum allowed reduced CT artifacts on imaging follow-up, which was especially useful in patients with type II endoleaks.

Idarubicin-loaded Beads for Chemoembolization of Hepatocellular Carcinoma: The IDASPHERE II Single-Arm Phase II Trial.

Background A prior in vitro study showed that idarubicin was the most cytotoxic agent for hepatocellular carcinoma (HCC) cell lines. Idarubicin-loaded beads for transarterial chemoembolization (TACE) were previously evaluated for the appropriate dose in a phase I dose-escalation study. Purpose To evaluate objective response rate (ORR), safety, and survival after TACE by using idarubicin-loaded beads for unresectable HCC. Materials and Methods This prospective single-arm phase II study was conducted between January 2015 and January 2017. Participants with unresectable HCC were included in the trial and underwent TACE with idarubicin-eluting beads. The primary end point was 6-month ORR assessed with independent central review by using modified Response Evaluation Criteria in Solid Tumors. Secondary end points were best ORR during the first 6 months, overall survival, progression-free survival, time to progression, and safety. A two-stage Fleming statistical design was used. Results Forty-six study participants (mean age, 71.2 years ± 10.2; six women and 40 men) were included; 44 participants underwent at least one TACE session. The 6-month ORR was 52% (23 of 44). The best ORR achieved was 68% (30 of 44). Fourteen of 44 (32%) participants underwent a curative treatment after TACE. Median progression-free survival, time to progression, and overall survival were 6.6 months, 9.5 months, and 18.6 months, respectively. TACE was discontinued for toxicity in four of 44 (9%) participants. The most frequent grade 3-4 adverse events were elevated aspartate aminotransferase (14 of 44, 32%), elevated γ-glutamyl transpeptidase (eight of 44, 18%), hyperbilirubinemia (seven of 44, 16%), elevated alanine aminotransferase (seven of 44, 16%), and pain (seven of 44, 16%). Conclusion Idarubicin-eluting beads showed a good safety profile and promising objective response rate and time to progression when used as part of a transarterial chemoembolization regimen for unresectable hepatocellular carcinoma. © RSNA, 2019 See also the editorial by Padia in this issue.

Comparison of tri-exponential decay versus bi-exponential decay and full fitting versus segmented fitting for modeling liver intravoxel incoherent motion diffusion MRI.

OBJECTIVES: To determine whether bi- or tri-exponential models, and full or segmented fittings, better fit the intravoxel incoherent motion (IVIM) imaging signal of healthy livers. METHODS: Diffusion-weighted images were acquired with a 3 T scanner using a respiratory-triggered echo-planar sequence and 16 b-values (0-800 s/mm2 ). Eighteen healthy volunteers had their livers scanned twice in the same session, and then once in another session. Liver parenchyma region-of-interest-based measurements were processed with bi-exponential and tri-exponential models, with both full fitting and segmented fitting (threshold b-value = 200 s/mm2 ). RESULTS: With the signal of all scans averaged, bi-exponential model full fitting showed Dslow  = 1.14 × 10-3  mm2 /s, Dfast  = 193.6 × 10-3  mm2 /s, and perfusion fraction (PF) = 16.9%, and segmented fitting showed Dslow  = 0.98 × 10-3  mm2 /s, Dfast  = 42.2 × 10-3  mm2 /s, and PF = 23.3%. IVIM parameters derived from the tri-exponential model were similar for full fitting and segmented fitting, with slow (D'slow  = 0.98 × 10-3  mm2 /s; F'slow  = 76.4 or 76.6%), fast (D'fast  = 15.1 or 15.4 × 10-3  mm2 /s; F'fast  = 11.8 or 11.7%) and very fast (D'Vfast  = 445.0 or 448.8 × 10-3  mm2 /s; F'Vfast  = 11.8 or 11.7%) diffusion compartments. The tri-exponential model provided an overall better fit than the bi-exponential model. For the bi-exponential model, full fitting provided a better fit at very low and low b-values compared with segmented fitting, with the latter tending to underestimate Dfast ; however, the segmented method demonstrated lower error in signal prediction for high b-values. Compared with full fitting, tri-exponential segmented fitting offered better scan-rescan reproducibility. CONCLUSION: For healthy liver, tri-exponential modeling is preferred to bi-exponential modeling. For the bi-exponential model, segmented fitting underestimates Dfast , but offers a more accurate estimation of Dslow .

Global metabolite profiles of rice brown planthopper-resistant traits reveal potential secondary metabolites for both constitutive and inducible defenses.

INTRODUCTION: Brown planthopper (BPH) is a phloem feeding insect that causes annual disease outbreaks, called hopper burn in many countries throughout Asia, resulting in severe damage to rice production. Currently, mechanistic understanding of BPH resistance in rice plant is limited, which has caused slow progression on developing effective rice varieties as well as effective farming practices against BPH infestation. OBJECTIVE: To reveal rice metabolic responses during 8 days of BPH attack, this study examined polar metabolome extracts of BPH-susceptible (KD) and its BPH-resistant isogenic line (IL308) rice leaves. METHODS: Ultra high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) was combined with multi-block PCA to analyze potential metabolites in response to BPH attack. RESULTS: This multivariate statistical model revealed different metabolic response patterns between the BPH-susceptible and BPH-resistant varieties during BPH infestation. The metabolite responses of the resistant IL308 variety occurred on Day 1, which was significantly earlier than those of the susceptible KD variety which showed an induced response by Days 4 and 8. BPH infestation caused metabolic perturbations in purine, phenylpropanoid, flavonoid, and terpenoid pathways. While found in both susceptible and resistant rice varieties, schaftoside (1.8 fold), iso-schaftoside (1.7 fold), rhoifolin (3.4 fold) and apigenin 6-C-α-L-arabinoside-8-C-ß-L-arabinoside levels (1.6 fold) were significantly increased in the resistant variety by Day 1 post-infestation. 20-hydroxyecdysone acetate (2.5 fold) and dicaffeoylquinic acid (4.7 fold) levels were considerably higher in the resistant rice variety than those in the susceptible variety, both before and after infestation, suggesting that these secondary metabolites play important roles in inducible and constitutive defenses against the BPH infestation. CONCLUSIONS: These potential secondary metabolites will be useful as metabolite markers and/or bioactive compounds for effective and durable approaches to address the BPH problem.

Dependence of intravoxel incoherent motion diffusion MR threshold b-value selection for separating perfusion and diffusion compartments and liver fibrosis diagnostic performance.

BACKGROUND: Intravoxel incoherent motion (IVIM) tissue parameters depend on the threshold b-value. PURPOSE: To explore how threshold b-value impacts PF ( f), Dslow ( D), and Dfast ( D*) values and their performance for liver fibrosis detection. MATERIAL AND METHODS: Fifteen healthy volunteers and 33 hepatitis B patients were included. With a 1.5-T magnetic resonance (MR) scanner and respiration gating, IVIM data were acquired with ten b-values of 10, 20, 40, 60, 80, 100, 150, 200, 400, and 800 s/mm2. Signal measurement was performed on the right liver. Segmented-unconstrained analysis was used to compute IVIM parameters and six threshold b-values in the range of 40-200 s/mm2 were compared. PF, Dslow, and Dfast values were placed along the x-axis, y-axis, and z-axis, and a plane was defined to separate volunteers from patients. RESULTS: Higher threshold b-values were associated with higher PF measurement; while lower threshold b-values led to higher Dslow and Dfast measurements. The dependence of PF, Dslow, and Dfast on threshold b-value differed between healthy livers and fibrotic livers; with the healthy livers showing a higher dependence. Threshold b-value = 60 s/mm2 showed the largest mean distance between healthy liver datapoints vs. fibrotic liver datapoints, and a classification and regression tree showed that a combination of PF (PF < 9.5%), Dslow (Dslow < 1.239 × 10-3 mm2/s), and Dfast (Dfast < 20.85 × 10-3 mm2/s) differentiated healthy individuals and all individual fibrotic livers with an area under the curve of logistic regression (AUC) of 1. CONCLUSION: For segmented-unconstrained analysis, the selection of threshold b-value = 60 s/mm2 improves IVIM differentiation between healthy livers and fibrotic livers.

Müller glial dysfunction during diabetic retinopathy in rats is reduced by the acrolein-scavenging drug, 2-hydrazino-4,6-dimethylpyrimidine.

AIMS/HYPOTHESIS: Recent studies suggest that abnormal function in Müller glial cells plays an important role in the pathogenesis of diabetic retinopathy. This is associated with the selective accumulation of the acrolein-derived advanced lipoxidation end-product, Nε-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine), on Müller cell proteins. The aim of the current study was to identify more efficacious acrolein-scavenging drugs and determine the effects of the most potent on Müller cell FDP-lysine accumulation and neuroretinal dysfunction during diabetes. METHODS: An ELISA-based in vitro assay was optimised to compare the acrolein-scavenging abilities of a range of drugs. This identified 2-hydrazino-4,6-dimethylpyrimidine (2-HDP) as a new and potent acrolein scavenger. The ability of this agent to modify the development of diabetic retinopathy was tested in vivo. Male Sprague Dawley rats were divided into three groups: (1) non-diabetic; (2) streptozotocin-induced diabetic; and (3) diabetic treated with 2-HDP in their drinking water for the duration of diabetes. Liquid chromatography high-resolution mass spectrometry was used to detect 2-HDP reaction products in the retina. Immunohistochemistry, real-time quantitative (q)RT-PCR and electroretinography were used to assess retinal changes 3 months after diabetes induction. RESULTS: 2-HDP was the most potent of six acrolein-scavenging agents tested in vitro (p < 0.05). In vivo, administration of 2-HDP reduced Müller cell accumulation of FDP-lysine at 3 months in rats rendered diabetic with streptozotocin (p < 0.001). A 2-HDP adduct was identified in the retinas of diabetic animals treated with this compound. 2-HDP supplementation was associated with reduced Müller cell gliosis (p < 0.05), reduced expression of the oxidative stress marker haem oxygenase-1 (p < 0.001) and partial normalisation of inwardly rectifying K+ channel 4.1 (Kir4.1) expression (p < 0.001 for staining in perivascular regions and the innermost region of the ganglion cell layer). Diabetes-induced retinal expression of inflammatory markers, inflammatory signalling compounds and activation of retinal microglial cells were all reduced in 2-HDP-treated animals. Retinal neurophysiological defects in diabetic animals, as indicated by changes in the electroretinogram 7 weeks after induction of diabetes, were also reduced by 2-HDP (p < 0.05-0.01 for b-wave amplitudes at flash intensities from -10 to +10 dB; p < 0.01 for time to peak of summed oscillatory potentials at +10 dB). CONCLUSIONS/INTERPRETATION: These findings support the hypothesis that Müller cell accumulation of FDP-lysine plays an important role in the development of diabetic retinopathy. Our results also suggest that 2-HDP may have therapeutic potential for delaying or treating this sight-threatening complication.

CT analysis of the aorta in giant-cell arteritis: a case-control study.

OBJECTIVES: Giant cell arteritis (GCA) is a large-vessel vasculitis whose diagnosis is confirmed by temporal artery biopsy. However, involvement of large vessels, especially the aorta, can be shown by imaging, which plays an increasing role in GCA diagnosis. The threshold above which aortic wall thickening, as measured by computed tomography (CT), is considered pathological is controversial, with values ranging from 2 to 3 mm. This study assessed aortic morphology by CT scan and its diagnostic value in GCA. METHODS: Altogether, 174 patients were included (64 with GCA, 43 with polymyalgia rheumatica and 67 controls). All patients had a CT scan at diagnosis or at inclusion for controls. Aortic wall thickness, aortic diameter and scores for atheroma were measured. Assessor was blinded to each patient's group. RESULTS: Aortic diameters and atheroma scores were similar between groups. Aortic wall thickness was greater in the GCA group, even after the exclusion of GCA patients with aortic wall thickness ≥3 mm. The receiver operating characteristic (ROC) curve showed that a wall thickness of 2.2 mm was the optimal threshold to diagnose GCA (sensitivity, 67%; specificity, 98%). CONCLUSIONS: Measuring aortic wall thickness by CT scan is effective to diagnose GCA. The optimal threshold to regard aortic wall thickening as pathological was ≥2.2 mm. KEY POINTS: • Imaging, including CT scan, plays an increasing role in GCA diagnosis • CT measurement of aortic wall thickness is useful to diagnose GCA • A 2.2-mm threshold allows the diagnosis of thickened aortic wall in GCA.

Outcomes of Transcatheter Arterial Embolization with a Modified N-Butyl Cyanoacrylate Glue for Spontaneous Iliopsoas and Rectus Sheath Hematomas in Anticoagulated Patients.

PURPOSE: To assess the efficacy and safety of n-butyl cyanoacrylate methacryloxy sulfolane (NBCA-MS) transcatheter arterial embolization for anticoagulation-related soft-tissue bleeding and to evaluate predictive factors of clinical success and 30-day mortality. MATERIALS AND METHODS: A retrospective review of 50 anticoagulated patients (25 male; mean age, 71.7 y ± 14.2; range, 19-87 y) who underwent emergent Glubran 2 NBCA-MS embolization for iliopsoas hematomas (IPHs; n = 38), rectus sheath hematomas (n = 11), or both (n = 1) between 2011 and 2016 was performed. Inclusion criteria were active bleeding on computed tomography (CT) and anticoagulation. The mean number of red blood cell (RBC) units transfused was 4.8 ± 3.2 (range, 0-14), median hemoglobin level before embolization was 9.7 g/dL (range, 6.2-18 g/dL), and median "mean blood pressure" (MBP) was 62.5 mm Hg (range, 58.3-75 mm Hg). Mean International Normalized Ratio before intervention was 2.5 ± 1.5 (range, 1.0-6.9). Angiograms revealed extravasation in 44 of 50 patients (88%). Mean hematoma volume was 1,119.2 cm3 ± 863.5 (range, 134.0-3,589.0 cm3). RESULTS: Technical success was achieved in 100% of patients, and 30-day clinical success was achieved in 66% of patients. Recurrent bleeding and mortality rates within 30 days of embolization were 34% and 44%, respectively. No complications related to the embolization procedure occurred. Lower MBP (P = .003), greater number of RBC units transfused (P = .003), greater volume of hematoma (P = .04), and IPH location (P = .02) were associated with decreased clinical success. Clinical failure (P = .00002), lower MBP (P = .004), greater number of RBC units transfused (P = .002), and IPH location (P = .01) were significantly associated with higher 30-day mortality rates. CONCLUSIONS: Transcatheter arterial embolization with NBCA-MS is safe and effective in treating refractory soft-tissue bleeding in anticoagulated patients despite the high mortality rates associated with this patient population.

Removal of evidential motion-contaminated and poorly fitted image data improves IVIM diffusion MRI parameter scan-rescan reproducibility.

Background It has been reported that intravoxel incoherent motion (IVIM) diffusion magnetic resonance imaging (MRI) scan-rescan reproducibility is unsatisfactory. Purpose To study IVIM MRI parameter reproducibility for liver parenchyma after the removal of motion-contaminated and/or poorly fitted image data. Material and Methods Eighteen healthy volunteers had liver scans twice in the same session to assess scan-rescan repeatability, and again in another session after an average interval of 13 days to assess reproducibility. Diffusion-weighted images were acquired with a 3-T scanner using respiratory-triggered echo-planar sequence and 16 b-values (0-800 s/mm2). Measurement was performed on the right liver with segment-unconstrained least square fitting. Image series with evidential anatomical mismatch, apparent artifacts, and poorly fitted signal intensity vs. b-value curve were excluded. A minimum of three slices was deemed necessary for IVIM parameter estimation. Results With a total 54 examinations, six did not satisfy inclusion criteria, leading to a success rate of 89%, and 14 volunteers were finally included for the repeatability/reproducibility study. A total of 3-10 slices per examination (mean = 5.3 slices, median = 5 slices) were utilized for analysis. Using threshold b-value = 80 s/mm2, the coefficient of variation and within-subject coefficient of variation for repeatability were 2.86% and 3.36% for Dslow, 3.81% and 4.24% for perfusion fraction (PF), 18.16% and 24.88% for Dfast; and those for reproducibility were 2.48% and 3.24% for Dslow, 4.91% and 5.38% for PF, and 21.18% and 30.89% for Dfast. Conclusion Removal of motion-contaminated and/or poorly fitted image data improves IVIM parameter reproducibility.

Identification of systemic immune response markers through metabolomic profiling of plasma from calves given an intra-nasally delivered respiratory vaccine.

Vaccination procedures within the cattle industry are important disease control tools to minimize economic and welfare burdens associated with respiratory pathogens. However, new vaccine, antigen and carrier technologies are required to combat emerging viral strains and enhance the efficacy of respiratory vaccines, particularly at the point of pathogen entry. New technologies, specifically metabolomic profiling, could be applied to identify metabolite immune-correlates representative of immune protection following vaccination aiding in the design and screening of vaccine candidates. This study for the first time demonstrates the ability of untargeted UPLC-MS metabolomic profiling to identify metabolite immune correlates characteristic of immune responses following mucosal vaccination in calves. Male Holstein Friesian calves were vaccinated with Pfizer Rispoval® PI3 + RSV intranasal vaccine and metabolomic profiling of post-vaccination plasma revealed 12 metabolites whose peak intensities differed significantly from controls. Plasma levels of glycocholic acid, N-[(3α,5ß,12α)-3,12-Dihydroxy-7,24-dioxocholan-24-yl]glycine, uric acid and biliverdin were found to be significantly elevated in vaccinated animals following secondary vaccine administration, whereas hippuric acid significantly decreased. In contrast, significant upregulation of taurodeoxycholic acid and propionylcarnitine levels were confined to primary vaccine administration. Assessment of such metabolite markers may provide greater information on the immune pathways stimulated from vaccine formulations and benchmarking early metabolomic responses to highly immunogenic vaccine formulations could provide a means for rapidly assessing new vaccine formulations. Furthermore, the identification of metabolic systemic immune response markers which relate to specific cell signaling pathways of the immune system could allow for targeted vaccine design to stimulate key pathways which can be assessed at the metabolic level.