MR-guided joint reconstruction of activity and attenuation in brain PET-MR.

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MR-guided joint reconstruction of activity and attenuation in brain PET-MR.

Neuroimage. 2017 Sep 13;162:276-288

Authors: Mehranian A, Zaidi H, Reader AJ

Abstract
With the advent of time-of-flight (TOF) PET scanners, joint maximum-likelihood reconstruction of activity and attenuation (MLAA) maps has recently regained attention for the estimation of PET attenuation maps from emission data. However, the estimated attenuation and activity maps are scaled by unknown scaling factors. We recently demonstrated that in hybrid PET-MR, the scaling issue of this algorithm can be effectively addressed by imposing MR spatial constraints on the estimation of attenuation maps using a penalized MLAA (P-MLAA(+)) algorithm. With the advent of simultaneous PET-MR systems, MRI-guided PET image reconstruction has also gained attention for improving the quantitative accuracy of PET images, usually degraded by noise and partial volume effects. The aim of this study is therefore to increase the benefits of MRI information for improving the quantitative accuracy of PET images by exploiting MRI-based anatomical penalty functions to guide the reconstruction of both activity and attenuation maps during their joint estimation. We employed an anato-functional joint entropy penalty function for the reconstruction of activity and an anatomical quadratic penalty function for the reconstruction of attenuation. The resulting algorithm was referred to as P-MLAA(++) since it exploits both activity and attenuation penalty functions. The performance of the P-MLAA algorithms were compared with MLAA and the widely used activity reconstruction algorithms such as maximum likelihood expectation maximization (MLEM) and penalized MLEM (P-MLEM) both corrected for attenuation using a conventional MRI segmentation-based attenuation correction (MRAC) method. The studied methods were evaluated using simulations and clinical studies taking the PET image reconstructed using reference CT-based attenuation maps as a reference. The simulation results showed that the proposed method can notably improve the visual quality of the PET images by reducing noise while preserving structural boundaries and at the same time improving the quantitative accuracy of the PET images. Our clinical reconstruction results showed that the MLEM-MRAC, P-MLEM-MRAC, MLAA, P-MLAA(+) and P-MLAA(++) algorithms result in, on average, quantification errors of -13.5 ± 3.1%, -13.4 ± 3.1%, -2.0 ± 6.5%, -3.0 ± 3.5% and -4.2 ± 3.6%, respectively, in different regions of the brain. In conclusion, whilst the P-MLAA(+) algorithm showed the best overall quantification performance, the proposed P-MLAA(++) algorithm provided simultaneous partial volume and attenuation corrections with only a minor compromise of PET quantification.

PMID: 28918316 [PubMed – as supplied by publisher]

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Paradigm shift in head and neck oncology patient management

Paradigm shift in head and neck oncology patient management

van den Heuvell, C. V. L., van Zuuren, F., Wells, M., van der Laan, G. & Reintsema, H. 19-Sep-2017 In : Journal of otolaryngology-Head & neck surgery. 46, 6 p., 57

Research output: Scientific – peer-reviewComment/Letter to the editor

Original language English
Article number 57
Number of pages 6
Journal Journal of otolaryngology-Head & neck surgery
Volume 46
State Published – 19-Sep-2017
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Community participation in mosquito breeding site control: an interdisciplinary mixed methods study in Curaçao

Community participation in mosquito breeding site control: an interdisciplinary mixed methods study in Curaçao

Elsinga, J., van der Veen, H. T., Gerstenbluth, I., Burgerhof, J. G. M., Dijkstra, A., Grobusch, M. P., Tami, A. & Bailey, A. 19-Sep-2017 In : Parasites & Vectors. 10, 1, p. 434

Research output: Scientific – peer-reviewArticle

Original language English
Pages (from-to) 434
Journal Parasites & Vectors
Volume 10
Issue number 1
State Published – 19-Sep-2017
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Controlled, synchronized actuation of microdroplets by gravity in a superhydrophobic, 3D-printed device.

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Controlled, synchronized actuation of microdroplets by gravity in a superhydrophobic, 3D-printed device.

Anal Chim Acta. 2017 Oct 02;988:50-57

Authors: Oomen PE, Mulder JPSH, Verpoorte E, Oleschuk RD

Abstract
Droplet manipulation over open surfaces allows one to perform assays with a large degree of control and high throughput, making them appealing for applications in drug screening or (bio)analysis. However, the design, manufacturing and operation of these systems comes with high technical requirements. In this study we employ a commercial, low-friction, superhydrophobic coating, Ultra-Ever Dry(®), on a 3D-printed microfluidic device. The device features individual droplet compartments, which allow the manipulation of discrete droplets (10-50 μL) actuated by gravity alone. Simply by angling the device to normal in a 3D-printed holder and rocking in a “to and fro”-fashion, a sequence of droplets can be individually transferred to an electrochemical microelectrode detector and then to waste, while preserving the (chronological) order of samples. Multiple biological fluids (i.e. human saliva, urine and rat blood and serum) were successfully tested for compatibility with the device and actuation mechanism, demonstrating low slip angles and high contact angles. Biological matrix (protein) carryover was probed and effectively mitigated by incorporating aqueous rinse droplets as part of the analysis sequence. As a proof-of-concept, the enzyme-coupled, amperometric detection of glucose was carried out on individual rat serum droplets, enabling total analysis in ≈30 min, including calibration. The device is readily customizable, and the integration of droplet generation techniques and other sensor systems for different analytes of interest or applications can be realized in a plug and play fashion.

PMID: 28916103 [PubMed – in process]

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Coupled reactions by coupled enzymes: alcohol to lactone cascade with alcohol dehydrogenase-cyclohexanone monooxygenase fusions.

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Coupled reactions by coupled enzymes: alcohol to lactone cascade with alcohol dehydrogenase-cyclohexanone monooxygenase fusions.

Appl Microbiol Biotechnol. 2017 Sep 15;:

Authors: Aalbers FS, Fraaije MW

Abstract
The combination of redox enzymes for redox-neutral cascade reactions has received increasing appreciation. An example is the combination of an alcohol dehydrogenase (ADH) with a cyclohexanone monooxygenase (CHMO). The ADH can use NADP(+) to oxidize cyclohexanol to form cyclohexanone and NADPH. Both products are then used by CHMO to produce ε-caprolactone. In this study, these two redox-complementary enzymes were fused, to create a self-sufficient bifunctional enzyme that can convert alcohols to esters or lactones. Three different ADH genes were fused to a gene coding for a thermostable CHMO, in both orientations (ADH-CHMO and CHMO-ADH). All six fusion enzymes could be produced and purified. For two of the three ADHs, we found a clear difference between the two orientations: one that showed the expected ADH activity, and one that showed low to no activity. The ADH activity of each fusion enzyme correlated with its oligomerization state. All fusions retained CHMO activity, and stability was hardly affected. The TbADH-TmCHMO fusion was selected to perform a cascade reaction, producing ε-caprolactone from cyclohexanol. By circumventing substrate and product inhibition, a > 99% conversion of 200 mM cyclohexanol could be achieved in 24 h, with > 13,000 turnovers per fusion enzyme molecule.

PMID: 28916997 [PubMed – as supplied by publisher]

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Uric acid in major depressive and anxiety disorders.

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Uric acid in major depressive and anxiety disorders.

J Affect Disord. 2017 Sep 06;225:684-690

Authors: Black CN, Bot M, Scheffer PG, Snieder H, Penninx BWJH

Abstract
BACKGROUND: Uric acid has neuroprotective effects, owing to its antioxidant properties. Lowered antioxidant capacity, causing increased oxidative stress, may be involved in affective disorders and might be altered by antidepressants. This study investigated the association of plasma uric acid, the greatest contributor to blood antioxidant capacity, with major depressive disorder (MDD) and anxiety disorders.
METHODS: Data were from the Netherlands Study of Depression and Anxiety including patients with current (N = 1648), remitted (N = 609) MDD and/or anxiety disorders (of which N = 710 antidepressant users) and 618 controls. Diagnoses were established with the Composite International Diagnostic Interview. Symptom severity was assessed with the Inventory of Depressive Symptoms-Self Report, Beck Anxiety Inventory and Fear Questionnaire. Uric acid was measured in plasma. Analyses were adjusted for sociodemographic, health and lifestyle variables.
RESULTS: Plasma uric acid adjusted mean levels were lower in current MDD and/or anxiety disorder(s) (289μmol/l) compared to remitted disorders (298μmol/l, p < .001) and controls (299μmol/l, p < .001; Cohen’s d .10). This finding was independent of antidepressant use. Depressive (β-.05, p = .0012), anxiety (β-.04, p = .009) and phobic (β-.03, p = .036) symptom severity, and symptom duration (β-.04, p = .009) were negatively associated with uric acid.
LIMITATIONS: Limitations include the lack of data on dietary intake which could be a potential confounding factor. From these cross-sectional findings, the association between uric acid and psychopathology cannot be inferred to be causal.
CONCLUSION: This large scale study finds plasma uric acid levels are lower in current, but not remitted, MDD and/or anxiety disorders, according to a dose-response gradient. This suggests the involvement of decreased antioxidant status in affective disorders, and points to their potential as an avenue for treatment.

PMID: 28917195 [PubMed – as supplied by publisher]

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Curbing the lifestyle disease pandemic: making progress on an interdisciplinary research agenda for law and policy interventions

Original language English
Article number 25
Number of pages 5
Journal BMC International Health and Human Rights
Volume 17
State Published – 18-Sep-2017
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Relationship between drug burden and physical and cognitive functions in a sample of nursing home patients with dementia

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Changes in acid-base and ion balance during exercise in normoxia and normobaric hypoxia.

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Changes in acid-base and ion balance during exercise in normoxia and normobaric hypoxia.

Eur J Appl Physiol. 2017 Sep 15;:

Authors: Lühker O, Berger MM, Pohlmann A, Hotz L, Gruhlke T, Hochreiter M

Abstract
PURPOSE: Both exercise and hypoxia cause complex changes in acid-base homeostasis. The aim of the present study was to investigate whether during intense physical exercise in normoxia and hypoxia, the modified physicochemical approach offers a better understanding of the changes in acid-base homeostasis than the traditional Henderson-Hasselbalch approach.
METHODS: In this prospective, randomized, crossover trial, 19 healthy males completed an exercise test until voluntary fatigue on a bicycle ergometer on two different study days, once during normoxia and once during normobaric hypoxia (12% oxygen, equivalent to an altitude of 4500 m). Arterial blood gases were sampled during and after the exercise test and analysed according to the modified physicochemical and Henderson-Hasselbalch approach, respectively.
RESULTS: Peak power output decreased from 287 ± 9 Watts in normoxia to 213 ± 6 Watts in hypoxia (-26%, P < 0.001). Exercise decreased arterial pH to 7.21 ± 0.01 and 7.27 ± 0.02 (P < 0.001) during normoxia and hypoxia, respectively, and increased plasma lactate to 16.8 ± 0.8 and 17.5 ± 0.9 mmol/l (P < 0.001). While the Henderson-Hasselbalch approach identified lactate as main factor responsible for the non-respiratory acidosis, the modified physicochemical approach additionally identified strong ions (i.e. plasma electrolytes, organic acid ions) and non-volatile weak acids (i.e. albumin, phosphate ion species) as important contributors.
CONCLUSIONS: The Henderson-Hasselbalch approach might serve as basis for screening acid-base disturbances, but the modified physicochemical approach offers more detailed insights into the complex changes in acid-base status during exercise in normoxia and hypoxia, respectively.

PMID: 28914359 [PubMed – as supplied by publisher]

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Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

Original language English
Pages (from-to) 1211-1259
Number of pages 49
Journal The Lancet
Volume 390
Issue number 10100
State Published – 16-Sep-2017
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Global, regional, and national age-sex specific mortality for 264 causes of death, 1980-2016: a systematic analysis for the Global Burden of Disease Study 2016

Global, regional, and national age-sex specific mortality for 264 causes of death, 1980-2016: a systematic analysis for the Global Burden of Disease Study 2016

GBD 2016 Causes of Death Collaborators 16-Sep-2017 In : The Lancet. 390, 10100, p. 1151-1210 60 p.

Research output: Scientific – peer-reviewArticle

Original language English
Pages (from-to) 1151-1210
Number of pages 60
Journal The Lancet
Volume 390
Issue number 10100
State Published – 16-Sep-2017
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Global, regional, and national under-5 mortality, adult mortality, age-specific mortality, and life expectancy, 1970-2016: a systematic analysis for the Global Burden of Disease Study 2016

Global, regional, and national under-5 mortality, adult mortality, age-specific mortality, and life expectancy, 1970-2016: a systematic analysis for the Global Burden of Disease Study 2016

GBD 2016 Mortality Collaborators 16-Sep-2017 In : The Lancet. 390, 10100, p. 1084-1150 67 p.

Research output: Scientific – peer-reviewArticle

Original language English
Pages (from-to) 1084-1150
Number of pages 67
Journal The Lancet
Volume 390
Issue number 10100
State Published – 16-Sep-2017
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Lifestyle intervention to improve quality of life and prevent weight gain after renal transplantation: Design of the Active Care after Transplantation (ACT) randomized controlled trial

Original language English
Pages (from-to) 296
Journal Bmc nephrology
Volume 18
Issue number 1
State Published – 15-Sep-2017
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Identification of transforming growth factorbeta-lregulated microRNAs and the microRNAtargetomes in primary lung fibroblasts

Identification of transforming growth factorbeta-lregulated microRNAs and the microRNAtargetomes in primary lung fibroblasts

Ong, J., Timens, W., Rajendran, V., Algra, A., Spira, A., Lenburg, M. E., Campbell, J. D., van den Berge, M., Postma, D. S., van den Berg, A., Kluiver, J. & Brandsma, C-A. 14-Sep-2017 In : PLoS ONE. 12, 9, 24 p., e0183815

Research output: Scientific – peer-reviewArticle

Original language English
Article number e0183815
Number of pages 24
Journal PLoS ONE
Volume 12
Issue number 9
State Published – 14-Sep-2017
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Androgen and estrogen receptor imaging in metastatic breast cancer patients as a surrogate for tissue biopsies

Androgen and estrogen receptor imaging in metastatic breast cancer patients as a surrogate for tissue biopsies

Venema, C. M., Mammatas, L. H., Schröder, C. P., van Kruchten, M., Apollonio, G., Glaudemans, A. W. J. M., Bongaerts, A. H. H., Hoekstra, O. S., Verheul, H. M. W., Boven, E., van der Vegt, B., de Vries, E. F., de Vries, E. G. E., Boellaard, R., Menke-van der Houven van Oordt, C. W. & Hospers, G. A. 14-Sep-2017 In : Journal of Nuclear Medicine.

Research output: Scientific – peer-reviewArticle

Original language English
Journal Journal of Nuclear Medicine
State Accepted/In press – 14-Sep-2017
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Identification of transforming growth factor-beta-regulated microRNAs and the microRNA-targetomes in primary lung fibroblasts

Identification of transforming growth factor-beta-regulated microRNAs and the microRNA-targetomes in primary lung fibroblasts

Ong, J., Timens, W., Rajendran, V., Algra, A., Spira, A., Lenburg, M. E., Campbell, J. D., van den Berge, M., Postma, D. S., van den Berg, A., Kluiver, J. & Brandsma, C-A. 14-Sep-2017 In : PLoS ONE. 12, 9, 24 p., e0183815

Research output: Scientific – peer-reviewArticle

Original language English
Article number e0183815
Number of pages 24
Journal PLoS ONE
Volume 12
Issue number 9
State Published – 14-Sep-2017
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The human “secreted Klotho” alternative mRNA is a nonsense-mediated mRNA decay target and its splicing is dysregulated in renal disease

Original language English
Number of pages 63
Journal JCI Insight
State Accepted/In press – 14-Sep-2017
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Platelets as Modulators of Liver Diseases.

Related Articles

Platelets as Modulators of Liver Diseases.

Semin Thromb Hemost. 2017 Sep 12;:

Authors: Lisman T, Luyendyk JP

PMID: 28898899 [PubMed – as supplied by publisher]

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Distribution of Non-Persistent Endocrine Disruptors in Two Different Regions of the Human Brain

Distribution of Non-Persistent Endocrine Disruptors in Two Different Regions of the Human Brain

van der Meer, T. P., Artacho-Cordón, F., Swaab, D. F., Struik, D., Makris, K. C., Wolffenbuttel, B. H. R., Frederiksen, H. & van Vliet-Ostaptchouk, J. V. 13-Sep-2017 In : International Journal of Environmental Research and Public Health. 14, 9, 11 p.

Research output: Scientific – peer-reviewArticle

Original language English
Number of pages 11
Journal International Journal of Environmental Research and Public Health
Volume 14
Issue number 9
State Published – 13-Sep-2017
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Impact of common genetic determinants of Hemoglobin A1c on type 2 diabetes risk and diagnosis in ancestrally diverse populations: A transethnic genome-wide meta-analysis

Impact of common genetic determinants of Hemoglobin A1c on type 2 diabetes risk and diagnosis in ancestrally diverse populations: A transethnic genome-wide meta-analysis

Wheeler, E., Leong, A., Liu, C-T., Hivert, M-F., Strawbridge, R. J., Podmore, C., Li, M., Yao, J., Sim, X., Hong, J., Chu, A. Y., Zhang, W., Wang, X., Chen, P., Maruthur, N. M., Porneala, B. C., Sharp, S. J., Jia, Y., Kabagambe, E. K., Chang, L-C., Chen, W-M., Elks, C. E., Evans, D. S., Fan, Q., Giulianini, F., Go, M. J., Hottenga, J-J., Hu, Y., Jackson, A. U., Kanoni, S., Kim, Y. J., Kleber, M. E., Ladenvall, C., Lecoeur, C., Lim, S-H., Lu, Y., Mahajan, A., Marzi, C., Nalls, M. A., Navarro, P., Nolte, I. M., Rose, L. M., Rybin, D. V., Sanna, S., Shi, Y., Stram, D. O., Takeuchi, F., Tan, S. P., van der Most, P. J., Van Vliet-Ostaptchouk, J. V., Wong, A., Yengo, L., Zhao, W., Goel, A., Martinez Larrad, M. T., Radke, D., Salo, P., Tanaka, T., van Iperen, E. P. A., Abecasis, G., Afaq, S., Alizadeh, B. Z., Bertoni, A. G., Bonnefond, A., Böttcher, Y., Bottinger, E. P., Campbell, H., Carlson, O. D., Chen, C-H., Cho, Y. S., Garvey, W. T., Gieger, C., Goodarzi, M. O., Grallert, H., Hamsten, A., Hartman, C. A., Herder, C., Hsiung, C. A., Huang, J., Igase, M., Isono, M., Katsuya, T., Khor, C-C., Kiess, W., Kohara, K., Kovacs, P., Lee, J., Lee, W-J., Lehne, B., Li, H., Liu, J., Lobbens, S., Luan, J., Lyssenko, V., Meitinger, T., Miki, T., Miljkovic, I., Moon, S., Mulas, A., Müller, G., Müller-Nurasyid, M., Nagaraja, R., Nauck, M., Pankow, J. S., Polasek, O., Prokopenko, I., Ramos, P. S., Rasmussen-Torvik, L., Rathmann, W., Rich, S. S., Robertson, N. R., Roden, M., Roussel, R., Rudan, I., Scott, R. A., Scott, W. R., Sennblad, B., Siscovick, D. S., Strauch, K., Sun, L., Swertz, M., Tajuddin, S. M., Taylor, K. D., Teo, Y-Y., Tham, Y. C., Tönjes, A., Wareham, N. J., Willemsen, G., Wilsgaard, T., Hingorani, A. D., Egan, J., Ferrucci, L., Hovingh, G. K., Jula, A., Kivimaki, M., Kumari, M., Njølstad, I., Palmer, C. N. A., Serrano Ríos, M., Stumvoll, M., Watkins, H., Aung, T., Blüher, M., Boehnke, M., Boomsma, D. I., Bornstein, S. R., Chambers, J. C., Chasman, D. I., Chen, Y-D. I., Chen, Y-T., Cheng, C-Y., Cucca, F., de Geus, E. J. C., Deloukas, P., Evans, M. K., Fornage, M., Friedlander, Y., Froguel, P., Groop, L., Gross, M. D., Harris, T. B., Hayward, C., Heng, C-K., Ingelsson, E., Kato, N., Kim, B-J., Koh, W-P., Kooner, J. S., Körner, A., Kuh, D., Kuusisto, J., Laakso, M., Lin, X., Liu, Y., Loos, R. J. F., Magnusson, P. K. E., März, W., McCarthy, M. I., Oldehinkel, A. J., Ong, K. K., Pedersen, N. L., Pereira, M. A., Peters, A., Ridker, P. M., Sabanayagam, C., Sale, M., Saleheen, D., Saltevo, J., Schwarz, P. E., Sheu, W. H. H., Snieder, H., Spector, T. D., Tabara, Y., Tuomilehto, J., van Dam, R. M., Wilson, J. G., Wilson, J. F., Wolffenbuttel, B. H. R., Wong, T. Y., Wu, J-Y., Yuan, J-M., Zonderman, A. B., Soranzo, N., Guo, X., Roberts, D. J., Florez, J. C., Sladek, R., Dupuis, J., Morris, A. P., Tai, E-S., Selvin, E., Rotter, J. I., Langenberg, C., Barroso, I., Meigs, J. B. & EPIC-CVD Consortium 12-Sep-2017 In : PLOS MEDICINE. 14, 9, 30 p., e1002383

Research output: Scientific – peer-reviewArticle

Original language English
Article number e1002383
Number of pages 30
Journal PLOS MEDICINE
Volume 14
Issue number 9
State Published – 12-Sep-2017
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