Using multi-event hydrologic and hydraulic signatures from water level sensors to diagnose locations of uncertainty in integrated urban drainage models used in living digital twins.

Digital twins of urban drainage systems require simulation models that can adequately replicate the physical system. All models have their limitations, and it is important to investigate when and where simulation results are acceptable and to communicate the level of performance transparently to end users. This paper first defines a classification of four possible 'locations of uncertainty' in integrated urban drainage models. It then develops a structured framework for identifying and diagnosing various types of errors. This framework compares model outputs with in-sewer water level observations based on hydrologic and hydraulic signatures. The approach is applied on a real case study in Odense, Denmark, with examples from three different system sites: a typical manhole, a small flushing chamber, and an internal overflow structure. This allows diagnosing different model errors ranging from issues in the underlying asset database and missing hydrologic processes to limitations in the model software implementation. Structured use of signatures is promising for continuous, iterative improvements of integrated urban drainage models. It also provides a transparent way to communicate the level of model adequacy to end users.

Coronary artery calcium and intima-media thickness are associated with level of cytomegalovirus immunoglobulin G in HIV-infected patients.

Coinfection with cytomegalovirus (CMV) may be involved in cardiovascular disease in HIV-infected patients. We found that higher level of CMV immunoglobulin G (IgG) was independently associated with an increased risk of coronary artery calcium and higher intima-media thickness in HIV-infected patients but not in healthy controls after adjustment for other cardiovascular risk factors and levels of herpes viridae IgG.

Association between smoking status assessed with plasma-cotinine and inflammatory and endothelial biomarkers in HIV-positive and HIV-negative individuals.

OBJECTIVES: Smoking is a major contributor to mortality and morbidity in HIV-positive individuals. Our primary objective was to evaluate the association between smoking status determined by plasma cotinine (P-cotinine) concentration and inflammatory and endothelial biomarkers in HIV-positive versus HIV-negative individuals. METHODS: We studied eight inflammatory/endothelial biomarkers [high-sensitivity C-reactive protein (hsCRP), E-selectin, soluble vascular cell adhesion molecule 1 (sVCAM-1), soluble intercellular adhesion molecule 1 (sICAM-1), matrix metallopeptidase 9 (MMP-9), myeloperoxidase (MPO), tissue type plasminogen activator inhibitor 1 (tPAI) and endothelin] in 105 HIV-positive individuals and 105 HIV-negative individuals matched on age, sex and self-reported smoking status. Smoking status was determined using P-cotinine (a concentration > 14 ng/mL was defined as demonstrating exposure to smoke). We used linear regression models to (1) examine the association between smoking status and inflammatory/endothelial biomarkers in HIV-positive compared with HIV-negative individuals, and (2) to determine whether there was evidence to suggest that the impact of smoking status on the biomarkers differed between HIV-positive and HIV-negative individuals. RESULTS: Of the eight biomarkers, smokers had increased hsCRP, sICAM-1 and MMP-9 concentrations irrespective of HIV status and increasing P-cotinine concentration was associated with increasing hsCRP concentration. We found no interaction between smoking and HIV status. HIV infection was associated with increased hsCRP, E-selectin, sVCAM-1, sICAM-1 and MMP-9 concentrations. Self-reported smoking status differed substantially from smoking status assessed with P-cotinine. CONCLUSIONS: Several biomarkers were associated with smoking status and HIV status. However, our data do not indicate that the effects of smoking on the biomarkers differ between HIV-positive and HIV-negative individuals.

The clinical utility of FDG PET/CT among solid organ transplant recipients suspected of malignancy or infection.

PURPOSE: Solid organ transplant (SOT) recipients are at high risk of developing infections and malignancies. 18F-FDG PET/CT may enable timely detection of these diseases and help to ensure early intervention. We aimed to describe the clinical utility of FDG PET/CT in consecutive, diagnostic unresolved SOT recipients transplanted from January 2004 to May 2015. METHODS: Recipients with a post-transplant FDG PET/CT performed as part of diagnostic work-up were included. Detailed chart reviews were done to extract relevant clinical information and determine the final diagnosis related to the FDG PET/CT. Based on á priori defined criteria and the final diagnosis, results from each scan were classified as true or false, and diagnostic values determined. RESULTS: Among the 1,814 recipients in the cohort, 145 had an FDG PET/CT performed; 122 under the indication of diagnostically unresolved symptoms with a suspicion of malignancy or infection. The remaining (N = 23) had an FDG PET/CT to follow-up on a known disease or to stage a known malignancy. The 122 recipients underwent a total of 133 FDG PET/CT scans performed for a suspected malignancy (66 %) or an infection (34 %). Sensitivity, specificity, and positive and negative predictive values of the FDG PET/CT in diagnosing these conditions were 97, 84, 87, and 96 %, respectively. CONCLUSION: FDG PET/CT is an accurate diagnostic tool for the work-up of diagnostic unresolved SOT recipients suspected of malignancy or infection. The high sensitivity and NPV underlines the potential usefulness of PET/CT for excluding malignancy or focal infections in this often complex clinical situation.

Soluble urokinase plasminogen activator receptor (suPAR) is a novel, independent predictive marker of myocardial infarction in HIV-1-infected patients: a nested case-control study.

OBJECTIVES: Patients infected with HIV are at increased risk of myocardial infarction (MI). Increased plasma levels of the inflammatory biomarker soluble urokinase plasminogen activator receptor (suPAR) have been associated with increased risk of cardiovascular diseases (CVD), including MI in the general population. We tested suPAR as a predictive biomarker of MI in HIV-1-infected individuals. METHODS: suPAR levels were investigated in a nested case-control study of 55 HIV-1-infected cases with verified first-time MI and 182 HIV-1-infected controls with no known CVD. Controls were matched for age, gender, duration of antiretroviral therapy (ART), smoking and no known CVD. suPAR was measured in the four plasma samples available for each patient at different time-points; 1, Before initiation of ART; 2, 3 months after initiation of ART; 3, 1 year before the case's MI; and 4, The last sample available before the case's MI. RESULTS: In unadjusted conditional regression analysis, higher levels of suPAR were associated with a significant increase in risk of MI at all time-points. Patients in the third and fourth suPAR quartiles had a three- to 10-fold higher risk of MI compared to patients in the lowest suPAR quartile at all time-points. suPAR remained a strong significant predictor of MI, when adjusting for HIV-1 RNA, total cholesterol, triglycerides and high-density lipoprotein. CONCLUSION: Elevated suPAR levels were associated with increased risk of MI in HIV-infected patients, suggesting that suPAR could be a useful biomarker for prediction of first-time MI in this patient group, even years before the event.

Exercise training favors increased insulin-stimulated glucose uptake in skeletal muscle in contrast to adipose tissue: a randomized study using FDG PET imaging.

Physical exercise increases peripheral insulin sensitivity, but regional differences are poorly elucidated in humans. We investigated the effect of aerobic exercise training on insulin-stimulated glucose uptake in five individual femoral muscle groups and four different adipose tissue regions, using dynamic (femoral region) and static (abdominal region) 2-deoxy-2-[¹8F]fluoro-d-glucose (FDG) PET/CT methodology during steady-state insulin infusion (40 mU·m⁻²·min⁻¹). Body composition was measured by dual X-ray absorptiometry and MRI. Sixty-one healthy, sedentary [V(O2max) 36(5) ml·kg⁻¹·min⁻¹; mean(SD)], moderately overweight [BMI 28.1(1.8) kg/m²], young [age: 30(6) yr] men were randomized to sedentary living (CON; n = 17 completers) or moderate (MOD; 300 kcal/day, n = 18) or high (HIGH; 600 kcal/day, n = 18) dose physical exercise for 11 wk. At baseline, insulin-stimulated glucose uptake was highest in femoral skeletal muscle followed by intraperitoneal visceral adipose tissue (VAT), retroperitoneal VAT, abdominal (anterior + posterior) subcutaneous adipose tissue (SAT), and femoral SAT (P < 0.0001 between tissues). Metabolic rate of glucose increased similarly (~30%) in the two exercise groups in femoral skeletal muscle (MOD 24[9, 39] µmol·kg⁻¹·min⁻¹, P = 0.004; HIGH 22[9, 35] µmol·kg⁻¹·min⁻¹, P = 0.003) (mean[95% CI]) and in five individual femoral muscle groups but not in femoral SAT. Standardized uptake value of FDG decreased ~24% in anterior abdominal SAT and ~20% in posterior abdominal SAT compared with CON but not in either intra- or retroperitoneal VAT. Total adipose tissue mass decreased in both exercise groups, and the decrease was distributed equally among subcutaneous and intra-abdominal depots. In conclusion, aerobic exercise training increases insulin-stimulated glucose uptake in skeletal muscle but not in adipose tissue, which demonstrates some interregional differences.

Preoperative PET/CT in early-stage breast cancer.

BACKGROUND: The aim of this study was to assess the diagnostic and therapeutic impact of preoperative positron emission tomography and computed tomography (PET/CT) in the initial staging of patients with early-stage breast cancer. PATIENTS AND METHODS: A total of 103 consecutive patients with newly diagnosed operable breast cancer with tumors ≥2 cm were independently examined preoperatively with conventional assessment (mammography, breast/axillary ultrasound, chest X-ray and blood samples) and PET/CT with no prior knowledge of the other. RESULTS: PET/CT identified a primary tumor in all but three patients (97%). PET/CT solely detected distant metastases (ovary, bones and lung) in 6 patients and new primary cancers (ovary, lung) in another two patients, as well as 12 cases of extra-axillary lymph node involvement. In 15 patients (15%), extra-axillary malignancy was detected by PET/CT only, leading to an upgrade of initial staging in 14% (14/103) and ultimately a modification of planned treatment in 8% (8/103) of patients. CONCLUSIONS: PET/CT is a valuable tool to provide information on extra-axillary lymph node involvement, distant metastases and other occult primary cancers. Preoperative (18)F-fluorodeoxyglucose-PET/CT has a substantial impact on initial staging and on clinical management in patients with early-stage breast cancer with tumors ≥2 cm.

PET in vivo generators 134Ce and 140Nd on an internalizing monoclonal antibody probe.

The in vivo-generator radionuclides 140Nd (t1/2 = 3.4 d) and 134Ce (t1/2 = 3.2 d) were used to trace a urokinase-type plasminogen activator (uPA)-targeting mouse monoclonal antibody, ATN-291, in U87 MG xenograft tumor-bearing mice. ATN-291 is known to internalize on the uPA/uPA-receptor pair, making it an appropriate targeting vector for investigating the fate of in vivo generator daughters on internalizing probes. Ante-mortem and post-mortem PET imaging at 120 h post-injection gave no indication of redistribution of the positron emitting daughter nuclides 134La and 140Pr from tumor tissue (p > 0.5). The lack of redistribution indicates that the parent radionuclides 134Ce and 140Nd could be considered as long-lived PET-diagnostic matches to therapeutic radionuclides like 177Lu, 161Tb and 225Ac when internalizing bioconjugates are employed.

Increased plasma aldosterone during atrial fibrillation declines following cardioversion.

OBJECTIVE: The renin-angiotensin-aldosterone system (RAAS) may be activated during atrial fibrillation (AF); our aim was to evaluate the level of aldosterone in patients with either permanent AF, persistent AF scheduled for cardioversion or patients in sinus rhythm (SR). We hypothesized that an increased level of aldosterone is found in patients with AF, decreasing in patients with restored SR. METHODS: The study included 60 patients with persistent AF scheduled for elective cardioversion, 19 patients with permanent AF, and a control group of 19 healthy individuals. All patients were examined and their aldosterone levels were measured. Measurement of aldosterone was repeated at follow-up 1, 30 and 180 days after successful cardioversion was achieved. Statistical analysis was conducted using the Kruskal-Wallis rank sum test and the paired t test. RESULTS: At follow-up, 1, 30, and 180 days after successful cardioversion of the patients with persistent AF, data showed that 49, 27, and 21 patients, respectively, were still in SR. At baseline, median values of plasma aldosterone in the healthy controls, the patients with persistent AF and those with permanent AF were 52, 68, and 80 pg/ml, respectively. The log aldosterone in patients with persistent AF was significantly increased when compared to the control group (p = 0.026). No effect of age and gender was observed. The level of aldosterone decreased over time in patients with AF undergoing cardioversion and maintaining SR, both at a follow-up of 30 days (p = 0.0032) and 180 days (p = 0.037). CONCLUSIONS: Patients with AF had a raised aldosterone level compared to the healthy control individuals. Restoration and maintenance of SR in patients with persistent AF significantly lowered the level of aldosterone up to 180 days after cardioversion, indicating activation of RAAS during AF.

Tumor repolarization by an advanced liposomal drug delivery system provides a potent new approach for chemo-immunotherapy.

Immunosuppressive cells in the tumor microenvironment allow cancer cells to escape immune recognition and support cancer progression and dissemination. To improve therapeutic efficacy, we designed a liposomal oxaliplatin formulation (PCL8-U75) that elicits cytotoxic effects toward both cancer and immunosuppressive cells via protease-mediated, intratumoral liposome activation. The PCL8-U75 liposomes displayed superior therapeutic efficacy across all syngeneic cancer models in comparison to free-drug and liposomal controls. The PCL8-U75 depleted myeloid-derived suppressor cells and tumor-associated macrophages in the tumor microenvironment. The combination of improved cancer cell cytotoxicity and depletion of immunosuppressive populations of immune cells is attractive for combination with immune-activating therapy. Combining the PCL8-U75 liposomes with a TLR7 agonist induced immunological rejection of established tumors. This combination therapy increased intratumoral numbers of cancer antigen-specific cytotoxic T cells and Foxp3- T helper cells. These results are encouraging toward advancing liposomal drug delivery systems with anticancer and immune-modulating properties into clinical cancer therapy.

Changes in biomarkers of cardiovascular risk after a switch to abacavir in HIV-1-infected individuals receiving combination antiretroviral therapy.

OBJECTIVES: To investigate, using a longitudinal design, whether biomarkers of cardiovascular risk change after a switch to an abacavir (ABC)-containing regimen in HIV-1-infected individuals already receiving combination antiretroviral therapy (ART). METHODS: Thirty-five HIV-1-infected individuals who switched ART to an ABC-containing regimen were identified. Twenty-two HIV-1-infected individuals who switched ART from and to a non-ABC-containing regimen served as controls. Plasma concentrations of soluble vascular cell adhesion molecule 1 (sVCAM-1), soluble intercellular adhesion molecule 1 (sICAM-1), matrix metallopeptidase 9 (MMP9), myeloperoxidase (MPO) and high sensitivity C-reactive protein (hs-CRP) were measured in blood samples before the switch in ART, and 3 months and 12 months afterwards. Log10-transformed data were compared with paired t-tests. RESULTS: Median MMP9 increased from 45.5 to 64.4 microg/mL after 3 months of ABC exposure (P = 0.011) and remained increased after 12 months (64.2 microg/mL; P = 0.013). MPO increased from median 8.8 to 10.4 microg/mL (P = 0.036) after 3 months of ABC exposure but was not increased after 12 months of exposure (9.1 microg/mL). hs-CRP increased from 3.3 to 4.2 microg/mL after 3 months (P = 0.031) but was not increased after 12 months of exposure (2.8 microg/mL). Neither sVCAM-1 nor sICAM-1 changed after the initiation of ABC. No changes were observed in the control group. CONCLUSIONS: MMP9, MPO and hs-CRP all increased after a switch in ART to an ABC-containing regimen. This indicates increased cardiovascular risk in viral load-suppressed HIV-1-infected individuals switching to ABC and proposes a proinflammatory potential as the underlying pathogenetic mechanism.

Reduction in circulating markers of endothelial dysfunction in HIV-infected patients during antiretroviral therapy.

OBJECTIVES: Antiretroviral therapy (ART) in HIV-infected patients is associated with increased cardiovascular risk. Circulating markers of endothelial dysfunction may be used to study early atherogenesis. The aim of our study was to investigate changes in such markers during initiation of ART. METHODS: In 115 HIV-positive treatment-naïve patients, plasma lipids, E-selectin, soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), tissue-type plasminogen activator inhibitor 1 (tPAI-1) and high-sensitivity C-reactive protein (hsCRP) were measured before and after 2 and 14 months of ART. A control group of 30 healthy subjects was included. Values are mean+/-standard error of the mean. RESULTS: Prior to treatment, HIV-infected patients had elevated levels of sICAM-1 (296+/-24 vs. 144+/-12 ng/mL), tPAI-1 (18 473+/-1399 vs. 5490+/-576 pg/mL) and hsCRP (28 060+/-5530 vs. 6665+/-2063 ng/mL) compared with controls (P<0.001). In contrast, sVCAM-1 and E-selectin did not differ between the groups. Initiation of ART resulted in significantly lower levels of E-selectin (15.1+/-0.8; P<0.01), sICAM-1 (248+/-12 ng/mL; P<0.05), sVCAM-1 (766+/-33 ng/mL; P<0.001) and hsCRP (14 708+/-2358 ng/mL; P<0.001) after 2 months, which remained reduced at 14 months. tPAI-1 was not influenced by initiation of ART. CONCLUSIONS: Markers of endothelial dysfunction were elevated in treatment-naïve HIV-infected patients and were related to HIV RNA viral load. Initiation of ART reduced the levels of the majority of these markers. The positive effect of ART initiation was dependent on the duration of HIV infection prior to treatment.

Molecular pathology in vulnerable carotid plaques: correlation with [18]-fluorodeoxyglucose positron emission tomography (FDG-PET).

OBJECTIVES: Atherosclerosis is recognised as an inflammatory disease, and new diagnostic tools are warranted to evaluate plaque inflammatory activity and risk of cardiovascular events. We investigated [18]-fluorodeoxyglucose (FDG) uptake in vulnerable carotid plaques visualised by positron emission tomography (PET). Uptake was correlated to quantitative gene expression of known markers of inflammation and plaque vulnerability. METHODS: Ten patients with recent transient ischaemic attack and carotid artery stenosis (>50%) underwent combined FDG-PET and computed tomography angiography (CTA) the day before carotid endarterectomy. Plaque mRNA expression of the inflammatory cytokine interleukin 18 (IL-18), the macrophage-specific marker CD68 and the two proteinases, Cathepsin K and matrix metalloproteinase 9 (MMP-9), were quantified using real-time quantitative polymerase chain reaction. RESULTS: Consistent up-regulation of CD68 (3.8-fold+/-0.9; mean+/-standard error), Cathepsin K (2.1-fold+/-0.5), MMP-9 (122-fold+/-65) and IL-18 (3.4-fold+/-0.7) were found in the plaques, compared to reference-artery specimens. The FDG uptake by plaques was strongly correlated with CD68 gene expression (r=0.71, P=0.02). Any correlations with Cathepsin K, MMP-9 or IL-18 gene expression were weaker. CONCLUSIONS: FDG-PET uptake in carotid plaques is correlated to gene expression of CD68 and other molecular markers of inflammation and vulnerability.

Characteristics of 252 patients with bronchopulmonary neuroendocrine tumours treated at the Copenhagen NET Centre of Excellence.

BACKGROUND: Bronchopulmonary neuroendocrine tumours are divided into typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC). AIM: To thoroughly describe a cohort of 252 patients with TC, AC and LCNEC (SCLC excluded). MATERIAL AND METHODS: Collection of data from 252 patients referred to and treated at Rigshospitalet 2008-2016. Data was collected from electronic patient files and our prospective NET database. Statistics were performed in SPSS. RESULTS: 162 (64%) had TC, 29 (12%) had AC and 61 (24%) had LCNEC. Median age at diagnosis was 69 years (range: 19-89) with no difference between genders. Thoraco-abdominal CT was performed in all patients at diagnosis. FDG-PET/CT was performed in 207 (82%) at diagnosis and was positive in 95% of the entire cohort, with no difference between tumour types. Synaptophysin was positive in 98%, chromogranin A in 92% and CD56 in 97%. Mean Ki67 index was 5% in TC, 16% in AC and 69% in LCNEC (p < 0.001). Metastatic disease was found in 4% of TC, 27% of AC and 58% of LCNEC at time of initial diagnosis (p < 0.001). In total 179 patients (71%) underwent surgical resection; TC: 87%, AC: 72% and LCNEC: 28% (p < 0.001). Of the resected patients, 11 (6%) had recurrence. Five-year survival rate was 88% for TC, 63% for AC and 20% for LCNEC. CONCLUSION: In this comprehensive study of a cohort of 252 patients, one of the largest until date, with TC, AC and LCNEC, the gender distribution showed female predominance with 68%. FDG-PET/CT was positive in 95% of the patients independent of tumour type, which confirms that FDG-PET/CT should be a part of the preoperative work-up for TC, AC and LCNEC. Tumour type was the single most potent independent prognostic factor.

Recent advances in nuclear cardiology.

Nuclear cardiology is an essential part of functional, non-invasive, cardiac imaging. Significant advances have been made in nuclear cardiology since planar (201)thallium ((201)TI) scintigraphy was introduced for the evaluation of left ventricular (LV) perfusion nearly 40 years ago. The use of nuclear cardiology has been steadily increasing over the last 20 years with important steps being the introduction of (99m)technetium- ((99m)Tc)-labelled perfusion radiotracers, the change from only planar to now much more single photon emission computed tomography (SPECT) and positron emission tomography (PET), electrocardiogram gating of nuclear perfusion imaging, and finally introducing nuclear hybrid imaging using either SPECT or PET together with either computed tomography or magnetic resonance imaging. The indications have extended from nearly only coronary artery diseases to several non-coronary cardiac diseases. The advances in nuclear cardiology are discussed under the four headlines of: 1) myocardial perfusion, 2) cardiac performance including LV and right ventricular (RV) function, 3) myocardial metabolism, and 4) experimental nuclear cardiology.

Liposome-encapsulated chemotherapy: Current evidence for its use in companion animals.

Cytotoxic drugs encapsulated into liposomes were originally designed to increase the anticancer response, while minimizing off-target adverse effects. The first liposomal chemotherapeutic drug was approved for use in humans more than 20 years ago, and the first publication regarding its use in a canine cancer patient was published shortly thereafter. Regardless, no general application for liposomal cytotoxic drugs has been established in veterinary oncology till now. Due to the popularity of canines as experimental models for pharmacokinetic analyses and toxicity studies, multiple publications exist describing various liposomal drugs in healthy dogs. Also, some evidence for its use in veterinary cancer patients exists, especially in canine lymphoma, canine splenic hemangiosarcoma and feline soft tissue sarcoma, however, the results have not been overwhelming. Reasons for this may be related to inherent issues with the enhanced permeability and retention effect, the tumour phenomenon which liposomal drugs exploit. This effect seems very heterogeneously distributed in the tumour. Also, it is potentially not as ubiquitously occurring as once thought, and it may prove important to select patients for liposomal therapy on an individual, non-histology-oriented, basis. Concurrently, new developments with active-release modified liposomes in experimental models and humans will likely be relevant for veterinary patients as well, and holds the potential to improve the therapeutic response. It, however, does not resolve the other challenges that liposomal chemotherapy faces, and more work still needs to be done to determine which veterinary patients may benefit the most from liposomal chemotherapy.

Selection of suitable reference genes for normalization of genes of interest in canine soft tissue sarcomas using quantitative real-time polymerase chain reaction.

Quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) is a sensitive technique for quantifying gene expression. Stably expressed reference genes are necessary for normalization of RT-qPCR data. Only a few articles have been published on reference genes in canine tumours. The objective of this study was to demonstrate how to identify suitable reference genes for normalization of genes of interest in canine soft tissue sarcomas using RT-qPCR. Primer pairs for 17 potential reference genes were designed and tested in archival tumour biopsies from six dogs. The geNorm algorithm was used to analyse the most suitable reference genes. Eight potential reference genes were excluded from this final analysis because of their dissociation curves. ß-Glucuronidase (GUSB) and proteasome subunit, beta type, 6 (PSMB6) were most stably expressed with an M value of 0.154 and a CV of 0.053 describing their average stability. We suggest that choice of reference genes should be based on specific testing in every new experimental set-up.

Reproducibility of (18)F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR.

OBJECTIVE: To investigate reproducibility of fluorine-18 fludeoxyglucose ((18)F-FDG) uptake on (18)F-FDG positron emission tomography (PET)/CT and (18)F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: 30 patients with HNSCC were included in this prospective study. The patients were scanned twice before radiotherapy treatment with both PET/CT and PET/MR. Patients were scanned on the same scanners, 3 days apart and according to the same protocol. Metabolic tumour activity was measured by the maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively), and total lesion glycolysis from the metabolic tumour volume defined from ≥50% SUVmax. Bland-Altman analysis with limits of agreement, coefficient of variation (CV) from the two modalities were performed in order to test the reproducibility. Furthermore, CVs from SUVmax and SUVpeak were compared. The area under the curve from cumulative SUV-volume histograms were measured and tested for reproducibility of the distribution of (18)F-FDG uptake. RESULTS: 24 patients had two pre-treatment PET/CT scans and 21 patients had two pre-treatment PET/MR scans available for further analyses. Mean difference for SUVmax, peak and mean was approximately 4% for PET/CT and 3% for PET/MR, with 95% limits of agreement less than ±20%. CV was small (5-7%) for both modalities. There was no significant difference in CVs between PET/CT and PET/MR (p = 0.31). SUVmax was not more reproducible than SUVpeak (p = 0.09). CONCLUSION: (18)F-FDG uptake in PET/CT and PET/MR is highly reproducible and we found no difference in reproducibility between PET/CT and PET/MR. ADVANCES IN KNOWLEDGE: This is the first report to test reproducibility of PET/CT and PET/MR.

Combined PET/MRI: Multi-modality Multi-parametric Imaging Is Here: Summary Report of the 4th International Workshop on PET/MR Imaging; February 23-27, 2015, Tübingen, Germany.

This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both technical versatility and acceptance by clinical and research-driven users from the status quo of last year. Still, with only minimal evidence of progress made in exploiting the true complementary nature of the PET and MRI-based information, PET/MRI is still yet to achieve its potential. In that regard, the conclusion of last year's meeting "the real work has just started" still holds true.

Histaminergic activation of the hypothalamic-pituitary-adrenal axis.

Centrally administered histamine (HA) stimulates the secretion of adenohypophysial POMC-derived peptides, which subsequently cause release of corticosterone. The effect of HA on POMC-derived peptide release is indirect, and it is possible that hypothalamic neurons containing corticotropin-releasing hormone (CRH), arginine vasopressin (AVP), or oxytocin (OT) are involved in the mediation of this response. We studied the effect of HA on: 1) expression of CRH, AVP, and OT messenger RNA (mRNA) at the hypothalamic level; 2) expression of c-fos and POMC mRNA at the pituitary level; and 3) peripheral plasma levels of AVP, OT, ACTH, beta-endorphin (beta-END), and corticosterone. HA (270 nmol) infused intracerebroventricularly increased the expression of CRH, AVP, and OT mRNA in the paraventricular nucleus as well as that of OT mRNA in the supraoptic nucleus of the hypothalamus. At the pituitary level the expression of mRNA for c-fos and POMC increased in the anterior but not in the intermediate lobe in response to HA. Plasma levels of AVP, OT, ACTH, beta-END, and corticosterone all increased in response to central HA administration. Circulating levels of AVP and OT peaked after 5 min, ACTH and beta-END after 15 min, whereas corticosterone levels were highest after 30 min. In concert with our earlier discoveries, the present data support the hypothesis that HA-induced secretion of ACTH and beta-END is mediated via central activation of hypothalamic neuroendocrine neurons containing CRH, AVP, and/or OT.