43 results on '"Moosmann J"'
Search Results
2. Pore formation and melt pool analysis of laser welded Al-Cu joints using synchrotron radiation
- Author
-
Hollatz, S., Hummel, M., Olowinsky, A., Gillner, A., Beckmann, F., and Moosmann, J.
- Published
- 2022
- Full Text
- View/download PDF
3. Blue diode lasers – Understanding and influencing melt pool dynamics in copper
- Author
-
Heine, L., primary, Schlett, M., additional, Britten, S., additional, Arndt, A., additional, Spurk, C., additional, Hummel, M., additional, Beckmann, F., additional, and Moosmann, J., additional
- Published
- 2023
- Full Text
- View/download PDF
4. Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries
- Author
-
Škorić-Milosavljević, D, Tadros, R, Bosada, FM, Tessadori, F, van Weerd, JH, Woudstra, OI, Tjong, FVY, Lahrouchi, N, Bajolle, F, Cordell, HJ, Agopian, AJ, Blue, GM, Barge-Schaapveld, DQCM, Gewillig, M, Preuss, C, Lodder, EM, Barnett, P, Ilgun, A, Beekman, L, van Duijvenboden, K, Bokenkamp, R, Müller-Nurasyid, M, Vliegen, HW, Konings, TC, van Melle, JP, van Dijk, APJ, van Kimmenade, RRJ, Roos-Hesselink, JW, Sieswerda, GT, Meijboom, F, Abdul-Khaliq, H, Berger, F, Dittrich, S, Hitz, M-P, Moosmann, J, Riede, F-T, Schubert, S, Galan, P, Lathrop, M, Munter, HM, Al-Chalabi, A, Shaw, CE, Shaw, PJ, Morrison, KE, Veldink, JH, van den Berg, LH, Evans, S, Nobrega, MA, Aneas, I, Radivojkov-Blagojević, M, Meitinger, T, Oechslin, E, Mondal, T, Bergin, L, Smythe, JF, Altamirano-Diaz, L, Lougheed, J, Bouma, BJ, Chaix, M-A, Kline, J, Bassett, AS, Andelfinger, G, van der Palen, RLF, Bouvagnet, P, Clur, S-AB, Breckpot, J, Kerstjens-Frederikse, WS, Winlaw, DS, Bauer, UMM, Mital, S, Goldmuntz, E, Keavney, B, Bonnet, D, Mulder, BJ, Tanck, MWT, Bakkers, J, Christoffels, VM, Boogerd, CJ, Postma, AV, Bezzina, CR, Hubrecht Institute for Developmental Biology and Stem Cell Research, Cardiology, Cardiovascular Centre (CVC), Medical Biology, ACS - Heart failure & arrhythmias, ACS - Pulmonary hypertension & thrombosis, Human Genetics, Amsterdam Reproduction & Development (AR&D), Amsterdam Cardiovascular Sciences, General Paediatrics, Paediatric Cardiology, APH - Aging & Later Life, APH - Personalized Medicine, Epidemiology and Data Science, APH - Methodology, Pediatric surgery, and Physiology
- Subjects
Genome-wide association study ,Multifactorial Inheritance ,congenital, hereditary, and neonatal diseases and abnormalities ,Cardiac & Cardiovascular Systems ,Physiology ,Transposition of Great Vessels ,Vascular damage Radboud Institute for Health Sciences [Radboudumc 16] ,ZIC3 MUTATIONS ,DE-NOVO ,Polymorphism, Single Nucleotide ,Wnt-5a Protein ,Article ,Mice ,OF-FUNCTION MUTATIONS ,Congenital Heart Disease ,Genome-wide Association Study ,Single Nucleotide Polymorphism ,Transposition Of Great Vessels ,Animals ,Humans ,MALFORMATIONS ,Myocytes, Cardiac ,GENOME-WIDE ASSOCIATION ,Transposition of great vessels ,Cells, Cultured ,Zebrafish ,Congenital heart disease ,WNT5A MUTATIONS ,Science & Technology ,HERITABILITY ,Wnt-5a protein ,Hematology ,DEFECTS ,Single nucleotide polymorphism ,CONGENITAL HEART-DISEASE ,Peripheral Vascular Disease ,Cardiovascular System & Cardiology ,HYPOPLASTIC LEFT-HEART ,T-Box Domain Proteins ,Cardiology and Cardiovascular Medicine ,Life Sciences & Biomedicine - Abstract
Rationale: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored. Objective: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA. Methods and Results: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10 -10 , OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10 -5 ). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A , which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart. Conclusions: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A . Genomic and functional data support a causal role of WNT5A at the locus.
- Published
- 2022
5. Common Genetic Variants Contribute to Risk of Transposition of the Great Arteries
- Author
-
Škorić-Milosavljević, D., Tadros, R., Bosada, F.M., Tessadori, F., Weerd, J.H. van, Woudstra, O.I., Tjong, F.V.Y., Lahrouchi, N., Bajolle, F., Cordell, H.J., Agopian, A.J., Blue, G.M., Barge-Schaapveld, D., Gewillig, M., Preuss, C., Lodder, E.M., Barnett, P., Ilgun, A., Beekman, L., Duijvenboden, K. van, Bokenkamp, R., Müller-Nurasyid, M., Vliegen, H.W., Konings, T.C., Melle, J.P. van, Dijk, A.P.J. van, Kimmenade, R.R.J. van, Roos-Hesselink, J.W., Sieswerda, G.T., Meijboom, F., Abdul-Khaliq, H., Berger, F, Dittrich, S., Hitz, M.P., Moosmann, J., Riede, F.T., Schubert, S., Galan, P., Lathrop, M., Munter, H.M., Al-Chalabi, A., Shaw, C.E., Shaw, P.J., Morrison, K.E., Veldink, J.H., Berg, L.H. van den, Evans, S., Nobrega, M.A., Aneas, I., Radivojkov-Blagojević, M., Meitinger, T., Oechslin, E., Mondal, T., Bergin, L., Smythe, J.F., Altamirano-Diaz, L., Lougheed, J., Bouma, B.J., Chaix, M.A., Kline, J., Bassett, A.S., Andelfinger, G., Palen, R.L.F. van der, Bouvagnet, P., Clur, S.B., Breckpot, J., Kerstjens-Frederikse, W.S., Winlaw, D.S., Bauer, U.M.M., Mital, S., Goldmuntz, E., Keavney, B., Bonnet, D., Mulder, B. J. M., Tanck, M.W.T., Bakkers, J., Christoffels, V.M., Boogerd, C.J., Postma, A.V., Bezzina, C.R., Škorić-Milosavljević, D., Tadros, R., Bosada, F.M., Tessadori, F., Weerd, J.H. van, Woudstra, O.I., Tjong, F.V.Y., Lahrouchi, N., Bajolle, F., Cordell, H.J., Agopian, A.J., Blue, G.M., Barge-Schaapveld, D., Gewillig, M., Preuss, C., Lodder, E.M., Barnett, P., Ilgun, A., Beekman, L., Duijvenboden, K. van, Bokenkamp, R., Müller-Nurasyid, M., Vliegen, H.W., Konings, T.C., Melle, J.P. van, Dijk, A.P.J. van, Kimmenade, R.R.J. van, Roos-Hesselink, J.W., Sieswerda, G.T., Meijboom, F., Abdul-Khaliq, H., Berger, F, Dittrich, S., Hitz, M.P., Moosmann, J., Riede, F.T., Schubert, S., Galan, P., Lathrop, M., Munter, H.M., Al-Chalabi, A., Shaw, C.E., Shaw, P.J., Morrison, K.E., Veldink, J.H., Berg, L.H. van den, Evans, S., Nobrega, M.A., Aneas, I., Radivojkov-Blagojević, M., Meitinger, T., Oechslin, E., Mondal, T., Bergin, L., Smythe, J.F., Altamirano-Diaz, L., Lougheed, J., Bouma, B.J., Chaix, M.A., Kline, J., Bassett, A.S., Andelfinger, G., Palen, R.L.F. van der, Bouvagnet, P., Clur, S.B., Breckpot, J., Kerstjens-Frederikse, W.S., Winlaw, D.S., Bauer, U.M.M., Mital, S., Goldmuntz, E., Keavney, B., Bonnet, D., Mulder, B. J. M., Tanck, M.W.T., Bakkers, J., Christoffels, V.M., Boogerd, C.J., Postma, A.V., and Bezzina, C.R.
- Abstract
Item does not contain fulltext, RATIONALE: Dextro-transposition of the great arteries (D-TGA) is a severe congenital heart defect which affects approximately 1 in 4,000 live births. While there are several reports of D-TGA patients with rare variants in individual genes, the majority of D-TGA cases remain genetically elusive. Familial recurrence patterns and the observation that most cases with D-TGA are sporadic suggest a polygenic inheritance for the disorder, yet this remains unexplored. OBJECTIVE: We sought to study the role of common single nucleotide polymorphisms (SNPs) in risk for D-TGA. METHODS AND RESULTS: We conducted a genome-wide association study in an international set of 1,237 patients with D-TGA and identified a genome-wide significant susceptibility locus on chromosome 3p14.3, which was subsequently replicated in an independent case-control set (rs56219800, meta-analysis P=8.6x10(-10), OR=0.69 per C allele). SNP-based heritability analysis showed that 25% of variance in susceptibility to D-TGA may be explained by common variants. A genome-wide polygenic risk score derived from the discovery set was significantly associated to D-TGA in the replication set (P=4x10(-5)). The genome-wide significant locus (3p14.3) co-localizes with a putative regulatory element that interacts with the promoter of WNT5A, which encodes the Wnt Family Member 5A protein known for its role in cardiac development in mice. We show that this element drives reporter gene activity in the developing heart of mice and zebrafish and is bound by the developmental transcription factor TBX20. We further demonstrate that TBX20 attenuates Wnt5a expression levels in the developing mouse heart. CONCLUSIONS: This work provides support for a polygenic architecture in D-TGA and identifies a susceptibility locus on chromosome 3p14.3 near WNT5A. Genomic and functional data support a causal role of WNT5A at the locus.
- Published
- 2022
6. Capillarity and active cell movement at mesendoderm translocation in the Xenopus gastrula
- Author
-
Nagel, M., Barua, D., Damm, E., Kashef, J., Hofmann, R., Ershov, A., Cecilia, A., Moosmann, J., Baumbach, T., and Winklbauer, R.
- Abstract
During Xenopus gastrulation, leading edge mesendoderm (LEM) advances animally as a wedge-shaped cell mass over the vegetally moving blastocoel roof (BCR). We show that close contact across the BCR-LEM interface correlates with attenuated net advance of the LEM, which is pulled forward by tip cells while the remaining LEM frequently separates from the BCR. Nevertheless, lamellipodia persist on the detached LEM surface. They attach to adjacent LEM cells and depend on PDGF-A, cell-surface fibronectin and cadherin. We argue that active cell motility on the LEM surface prevents adverse capillary effects in the liquid LEM tissue as it moves by being pulled. It counters tissue surface-tension effects with oriented cell movement and bulges the LEM surface out to keep it close to the curved BCR without attaching to it. Proximity to the BCR is necessary, in turn, for the maintenance and orientation of lamellipodia that permit mass cell movement with minimal substratum contact. Together with a similar process in epithelial invagination, vertical telescoping, the cell movement at the LEM surface defines a novel type of cell rearrangement: vertical shearing.
- Published
- 2021
7. High-resolution quantitative phase-contrast x-ray imaging for biomedical samples at PETRA III
- Author
-
Riedel, M., Gustschin, A., Ushakov, L., Noichl, W., Taphorn, K., Busse, M., Beckmann, F., Hammel, J., Moosmann, J., and Herzen, J.
- Abstract
Phase-contrast imaging is one of the standard X-ray imaging methods at synchrotron beamlines and has already proven to be beneficial for soft-tissue visualization. However, most implementations use single-distance inline phase-contrast techniques, and are thus not able to provide quantitative information. To access these, grating-based imaging (GBI) setups or, rather recently, speckle-based imaging (SBI) methods can be used. We built a new grating-based setup at the beamline P05 operated by HZG at the storage ring PETRA III / DESY. This new setup overcomes the previously reported limitations in spatial resolution compared to inline phase-contrast imaging. Furthermore, it allows for accurate quantitative phase contrast micro computed tomography of biological soft tissue. We replaced the typically used sandpaper by a 2D phase-grating as a wavefront marker, which increased the visibility and allowed for using fewer phase steps. Combined with an existing SBI phase-retrieval algorithm, the so-called Unified Modulated Pattern Analysis (UMPA) and an optimized scan protocol, we reached a resolution below 4 microns in scan times less than two hours. We investigated stained and unstained tissue samples, to quantify the staining process of different tissue types and were able to observe an increase in electron density, dependent on the stain and tissue type. By this, we could show the successful operation of our setup to quantitatively investigate samples on a micro meter scale at the beamline P05.
- Published
- 2021
8. Assessing the interface ultrastructure of bone around biodegradable implants
- Author
-
Zeller-Plumhoff, B., Wieland, D.C.F., Malich, C., Krueger, D., Campbell, G., Moosmann, J., Galli, S., Wennerberg, A., and Willumeit-Roemer, R.
- Published
- 2019
9. High-resolution X-ray phase-contrast tomography from single-distance radiographs applied to developmental stages of Xenopus laevis
- Author
-
Moosmann, J, primary, Altapova, V, additional, Helfen, L, additional, Hänschke, D, additional, Hofmann, R, additional, and Baumbach, T, additional
- Published
- 2013
- Full Text
- View/download PDF
10. Multi-modal investigation of the bone micro- and ultrastructure, and elemental distribution in the presence of Mg-xGd screws at mid-term healing stages.
- Author
-
Iskhakova K, Cwieka H, Meers S, Helmholz H, Davydok A, Storm M, Baltruschat IM, Galli S, Pröfrock D, Will O, Gerle M, Damm T, Sefa S, He W, MacRenaris K, Soujon M, Beckmann F, Moosmann J, O'Hallaran T, Guillory RJ 2nd, Wieland DCF, Zeller-Plumhoff B, and Willumeit-Römer R
- Abstract
Magnesium (Mg) - based alloys are becoming attractive materials for medical applications as temporary bone implants for support of fracture healing, e.g. as a suture anchor. Due to their mechanical properties and biocompatibility, they may replace titanium or stainless-steel implants, commonly used in orthopedic field. Nevertheless, patient safety has to be assured by finding a long-term balance between metal degradation, osseointegration, bone ultrastructure adaptation and element distribution in organs. In order to determine the implant behavior and its influence on bone and tissues, we investigated two Mg alloys with gadolinium contents of 5 and 10 wt percent in comparison to permanent materials titanium and polyether ether ketone. The implants were present in rat tibia for 10, 20 and 32 weeks before sacrifice of the animal. Synchrotron radiation-based micro computed tomography enables the distinction of features like residual metal, degradation layer and bone structure. Additionally, X-ray diffraction and X-ray fluorescence yield information on parameters describing the bone ultrastructure and elemental composition at the bone-to-implant interface. Finally, with element specific mass spectrometry, the elements and their accumulation in the main organs and tissues are traced. The results show that Mg-xGd implants degrade in vivo under the formation of a stable degradation layer with bone remodeling similar to that of Ti after 10 weeks. No accumulation of Mg and Gd was observed in selected organs, except for the interfacial bone after 8 months of healing. Thus, we confirm that Mg-5Gd and Mg-10Gd are suitable material choices for bone implants., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)
- Published
- 2024
- Full Text
- View/download PDF
11. On the material dependency of peri-implant morphology and stability in healing bone.
- Author
-
Bruns S, Krüger D, Galli S, Wieland DCF, Hammel JU, Beckmann F, Wennerberg A, Willumeit-Römer R, Zeller-Plumhoff B, and Moosmann J
- Abstract
The microstructural architecture of remodeled bone in the peri-implant region of screw implants plays a vital role in the distribution of strain energy and implant stability. We present a study in which screw implants made from titanium, polyetheretherketone and biodegradable magnesium-gadolinium alloys were implanted into rat tibia and subjected to a push-out test four, eight and twelve weeks after implantation. Screws were 4 mm in length and with an M2 thread. The loading experiment was accompanied by simultaneous three-dimensional imaging using synchrotron-radiation microcomputed tomography at 5 μm resolution. Bone deformation and strains were tracked by applying optical flow-based digital volume correlation to the recorded image sequences. Implant stabilities measured for screws of biodegradable alloys were comparable to pins whereas non-degradable biomaterials experienced additional mechanical stabilization. Peri-implant bone morphology and strain transfer from the loaded implant site depended heavily on the biomaterial utilized. Titanium implants stimulated rapid callus formation displaying a consistent monomodal strain profile whereas the bone volume fraction in the vicinity of magnesium-gadolinium alloys exhibited a minimum close to the interface of the implant and less ordered strain transfer. Correlations in our data suggest that implant stability benefits from disparate bone morphological properties depending on the biomaterial utilized. This leaves the choice of biomaterial as situational depending on local tissue properties., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)
- Published
- 2023
- Full Text
- View/download PDF
12. Comparing x-ray phase-contrast imaging using a Talbot array illuminator to propagation-based imaging for non-homogeneous biomedical samples.
- Author
-
Riedel M, Taphorn K, Gustschin A, Busse M, Hammel JU, Moosmann J, Beckmann F, Fischer F, Thibault P, and Herzen J
- Subjects
- X-Rays, Microscopy, Phase-Contrast, Tomography, X-Ray Computed methods, Radiographic Image Interpretation, Computer-Assisted methods
- Abstract
Phase-contrast computed tomography can visualize soft tissue samples with high contrast. At coherent sources, propagation-based imaging (PBI) techniques are among the most common, as they are easy to implement and produce high-resolution images. Their downside is a low degree of quantitative data due to simplifying assumptions of the sample properties in the reconstruction. These assumptions can be avoided, by using quantitative phase-contrast techniques as an alternative. However, these often compromise spatial resolution and require complicated setups. In order to overcome this limitation, we designed and constructed a new imaging setup using a 2D Talbot array illuminator as a wavefront marker and speckle-based imaging phase-retrieval techniques. We developed a post-processing chain that can compensate for wavefront marker drifts and that improves the overall sensitivity. By comparing two measurements of biomedical samples, we demonstrate that the spatial resolution of our setup is comparable to the one of PBI scans while being able to successfully image a sample that breaks the typical homogeneity assumption used in PBI., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
13. Effects of Microbeam Irradiation on Rodent Esophageal Smooth Muscle Contraction.
- Author
-
Frerker B, Fiedler S, Kirschstein T, Lange F, Porath K, Sellmann T, Kutzner L, Wilde F, Moosmann J, Köhling R, Hildebrandt G, and Schültke E
- Subjects
- Animals, Muscle Contraction physiology, Muscle, Smooth, Rodentia, Esophagus
- Abstract
Background: High-dose-rate radiotherapy has shown promising results with respect to normal tissue preservation. We developed an ex vivo model to study the physiological effects of experimental radiotherapy in the rodent esophageal smooth muscle., Methods: We assessed the physiological parameters of the esophageal function in ex vivo preparations of the proximal, middle, and distal segments in the organ bath. High-dose-rate synchrotron irradiation was conducted using both the microbeam irradiation (MBI) technique with peak doses greater than 200 Gy and broadbeam irradiation (BBI) with doses ranging between 3.5-4 Gy., Results: Neither MBI nor BBI affected the function of the contractile apparatus. While peak latency and maximal force change were not affected in the BBI group, and no changes were seen in the proximal esophagus segments after MBI, a significant increase in peak latency and a decrease in maximal force change was observed in the middle and distal esophageal segments., Conclusion: No severe changes in physiological parameters of esophageal contraction were determined after high-dose-rate radiotherapy in our model, but our results indicate a delayed esophageal function. From the clinical perspective, the observed increase in peak latency and decreased maximal force change may indicate delayed esophageal transit.
- Published
- 2022
- Full Text
- View/download PDF
14. Degradation behavior and osseointegration of Mg-Zn-Ca screws in different bone regions of growing sheep: a pilot study.
- Author
-
Marek R, Ćwieka H, Donohue N, Holweg P, Moosmann J, Beckmann F, Brcic I, Schwarze UY, Iskhakova K, Chaabane M, Sefa S, Zeller-Plumhoff B, Weinberg AM, Willumeit-Römer R, and Sommer NG
- Abstract
Magnesium (Mg)-based implants are highly attractive for the orthopedic field and may replace titanium (Ti) as support for fracture healing. To determine the implant-bone interaction in different bony regions, we implanted Mg-based alloy ZX00 (Mg < 0.5 Zn < 0.5 Ca, in wt%) and Ti-screws into the distal epiphysis and distal metaphysis of sheep tibiae. The implant degradation and osseointegration were assessed in vivo and ex vivo after 4, 6 and 12 weeks, using a combination of clinical computed tomography, medium-resolution micro computed tomography (µCT) and high-resolution synchrotron radiation µCT (SRµCT). Implant volume loss, gas formation and bone growth were evaluated for both implantation sites and each bone region independently. Additionally, histological analysis of bone growth was performed on embedded hard-tissue samples. We demonstrate that in all cases, the degradation rate of ZX00-implants ranges between 0.23 and 0.75 mm/year. The highest degradation rates were found in the epiphysis. Bone-to-implant contact varied between the time points and bone types for both materials. Mostly, bone-volume-to-total-volume was higher around Ti-implants. However, we found an increased cortical thickness around the ZX00-screws when compared with the Ti-screws. Our results showed the suitability of ZX00-screws for implantation into the distal meta- and epiphysis., (© The Author(s) 2022. Published by Oxford University Press.)
- Published
- 2022
- Full Text
- View/download PDF
15. Fitter Fontans for future-Impact of physical exercise on cardiopulmonary function in Fontan patients.
- Author
-
Weigelt A, Fritsch R, Rottermann K, Wällisch W, Moosmann J, Dittrich S, Purbojo A, and Schöffl I
- Abstract
Background: In Fontans, exercise tolerance is poorer compared to their healthy peers. Higher V ˙ O 2 p e a k represents a strong predictor for mortality and morbidity in these patients. Cardiac rehabilitation programs have been shown to improve cardiopulmonary function in Fontans. More habitual physical activity should therefore lead to a better exercise tolerance., Methods: We performed cardiopulmonary exercise testing in 24 Fontan patients who had engaged in physical activity for a minimum of 3 h per week over their lifetime. As a control we performed cardiopulmonary exercise testing in 20 Fontan patients who had undertaken no physical activity or <3 h per week in the past., Results: A total of 44 Fontan patients was included (mean age 18.1 years). The mean parameters measured at peak exercise differed significantly between the active and inactive group (peak oxygen uptake [ V ˙ O 2 p e a k ] of 34.0 vs. 25.0 ml/min/kg, peak heart rate (HR) of 169.8/min vs. 139.8/min). Even though the O
2 pulse and the EF did not differ significantly between both groups, N-Terminal-Pro-B-Type Natriuretic Peptide (NT-pro BNP) was significantly higher in the inactive group. The two groups did not differ with respect to their cardiac function determined by magnetic resonance imaging (MRI). V ˙ O 2 p e a k was positively correlated with hours of sports performed by Fontans., Conclusions: V ˙ O 2 p e a k and maximum HR were significantly higher in Fontans who had been physically active compared to those who had been inactive. The values reported in this study were higher than in other studies and reached normal values for V ˙ O 2 p e a k for most Fontans in the physically active group. The positive correlation between V ˙ O 2 p e a k and physical activity is an indicator of the importance of incorporating physical exercise programs into the treatment of Fontan patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Weigelt, Fritsch, Rottermann, Wällisch, Moosmann, Dittrich, Purbojo and Schöffl.)- Published
- 2022
- Full Text
- View/download PDF
16. A classification of abdominal lymphatic perfusion patterns after Fontan surgery.
- Author
-
Schroeder C, Moosmann J, Cesnjevar R, Purbojo A, Rompel O, and Dittrich S
- Subjects
- Humans, Perfusion, Retrospective Studies, Fontan Procedure adverse effects, Lymphatic Abnormalities etiology, Lymphatic Vessels
- Abstract
Objectives: Complications after Fontan surgery have been associated with arise and classification of abnormal thoracic lymphatic perfusion pattern. This study compiles abnormal abdominal lymphatic perfusion patterns and investigates their impact on serum protein readings., Methods: We performed a retrospective analysis of patients who underwent magnetic resonance imaging with T2-weighted lymphatic imaging and serum protein measurements 6 months after having Fontan surgery. The abdominal lymphatic images were classified according to the anatomical lymphatic drainage patterns into 2 categories: (1) para-aortic (types 1-4); (2) portal-venous (types 1-3). Thoracic lymphatic images were classified (types 1-4) as described earlier., Results: A total of 71 patients were included in the study. Para-aortic lymphatic perfusion patterns were classified as type 1 in 4, type 2 in 13, type 3 in 37 and type 4 in16 out of 71 patients. Portal-venous lymphatic perfusion patterns were classified as type 1 in 20, type 2 in 10 and type 3 in 41 patients. Thoracic lymphatic perfusion patterns were classified as type 1 in 8, type 2 in 11, type 3 in 39 and type 4 in 13 patients. The serum protein level was 66 (interquartile range: 7.5) g/l (< standard value in 37%). Higher-grade para-aortic (p = 0.0062), portal-venous (p = 0.022) and thoracic (p = 0.011) lymphatic abnormalities were correlated with lower total serum protein levels. Higher ratings of para-aortic lymphatic abnormalities were significantly associated with higher ratings of portal-venous abnormalities (p < 0.0001). Ratings of para-aortic and portal-venous classifications were correlated with the thoracic classification (p < 0.001)., Conclusions: Abnormal abdominal lymphatic perfusion patterns can be classified according to anatomical structures with increasing severity. Higher grade abdominal and thoracic lymphatic perfusion patterns are associated with lower serum protein values., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
17. Synchrotron radiation-based phase-contrast microtomography of human dental calculus allows nondestructive analysis of inclusions: implications for archeological samples.
- Author
-
Power RC, Henry AG, Moosmann J, Beckmann F, Temming H, Roberts A, and Le Cabec A
- Abstract
Purpose : Dental calculus forms on teeth during the life of an individual and its investigation can yield information about diet, health status, and environmental pollution. Currently, the analytical techniques used to visualize the internal structure of human dental calculus and entrapped inclusions are limited and require destructive sampling, which cannot always be justified. Approach: We used propagation phase-contrast synchrotron radiation micro-computed tomography (PPC-SR- μ CT ) to non-destructively examine the internal organization of dental calculus, including its microstructure and entrapped inclusions, on both modern and archeological samples. Results: The virtual histological exploration of the samples shows that PPC-SR- μ CT is a powerful approach to visualize the internal organization of dental calculus. We identified several important features, including previously undetected negative imprints of enamel and dentine growth markers (perikymata and periradicular bands, respectively), the non-contiguous structure of calculus layers with multiple voids, and entrapped plant remains. Conclusions: PPC-SR- μ CT is an effective technique to explore dental calculus structural organization, and is especially powerful for enabling the identification of inclusions. The non-destructive nature of synchrotron tomography helps protect samples for future research. However, the irregular layers and frequent voids reveal a high heterogeneity and variability within calculus, with implications for research focusing on inclusions., (© 2022 The Authors.)
- Published
- 2022
- Full Text
- View/download PDF
18. Serial T2-Weighted Thoracic and Abdominal Lymphatic Imaging in Fontan Patients-New Insights into Dynamics of Lymphatic Abnormalities after Total Cavopulmonary Connection.
- Author
-
Moosmann J, Schroeder C, Rompel O, Purbojo A, and Dittrich S
- Abstract
Lymphatic congestion in single-ventricle patients has been associated with increased morbidity and poor outcomes. Little is known about the dynamics of lymphatic abnormalities over time, on their association with clinical presentation or response to catheter interventions. This retrospective, single-center study describes Fontan patients who underwent at least two magnetic resonance imaging (MRI) studies. T2-weighted lymphatic imaging was used to classify thoracic and abdominal (para-aortic and portal-venous) lymphatic abnormalities. The relationship between lymphatic congestion and hemodynamic changes after cardiac catheter interventions, clinical presentation and MRI data was analyzed. A total of 33 Fontan patients underwent at least two cardiac MRI studies. Twenty-two patients had two, eight had three and three had four lymphatic imaging studies (total of 80 MRIs studies). No significant changes in lymphatic classification between MRI 1 and 2 were observed for thoracic ( p = 0.400), para-aortic (0.670) and portal-venous ( p = 0.822) abnormalities. No significant correlation between lymphatic classification and hemodynamic changes after intervention or MRI parameters was found. This study illustrates thoracic and abdominal lymphatic abnormalities in serial T2-weighted imaging after Fontan. Fontan patients did not demonstrate significant changes in their lymphatic perfusion, despite clinical or hemodynamic changes. We assume that lymphatic congestion might develop after total cavopulmonary connection (TCPC) and remain relatively stable, despite further intervention targeting hemodynamic parameters.
- Published
- 2022
- Full Text
- View/download PDF
19. Prediction of High Bell Stages of Necrotizing Enterocolitis Using a Mathematic Formula for Risk Determination.
- Author
-
Diez S, Bell LE, Moosmann J, Weiss C, Müller H, and Besendörfer M
- Abstract
Necrotizing enterocolitis (NEC) continues to cause high morbidity and mortality. Identifying early predictors for severe NEC is essential to improve therapy and optimize timing for surgical intervention. We present a retrospective study of patients with NEC, treated between 2010 and 2020, trying to identify factors influencing the severity of NEC. Within the study period, 88 affected infants with NEC or NEC-like symptoms are analyzed. A multiple logistic regression analysis reveals the following three independent predictors for NEC in Bell stage III: red blood cell transfusion ( p = 0.027 with odds ratio (OR) = 3.298), sonographic findings ( p = 0.037; OR = 6.496 for patients with positive vs. patients without pathological findings) and cardiac anatomy ( p = 0.015; OR = 1.922 for patients with patent ductus arteriosus (PDA) vs. patients with congenital heart disease (CHD); OR = 5.478/OR = 2.850 for patients with CHD/PDA vs. patients without cardiac disease). Results are summarized in a clinical score for daily application in clinical routine. The score is easy to apply and combines clinically established parameters, helping to determine the timing of surgical intervention.
- Published
- 2022
- Full Text
- View/download PDF
20. COVID Vaccine-Associated Myocarditis in Adolescent Siblings: Does It Run in the Family?
- Author
-
Moosmann J, Gentles T, Occleshaw C, and Mitchelson B
- Abstract
The development of myocarditis after receiving messenger RNA vaccination against COVID-19 is well documented, particularly in adolescent and young adult males. We report a case of vaccine-associated myocarditis in adolescent brothers following their second dose of the BNT162b2 mRNA vaccine (Pfizer-BioNTech, Mainz, Germany). This report illustrates the need to better understand the mechanisms leading to myocarditis after mRNA vaccination.
- Published
- 2022
- Full Text
- View/download PDF
21. DMBT1 expression and neutrophil-to-lymphocyte ratio during necrotizing enterocolitis are influenced by impaired perfusion due to cardiac anomalies.
- Author
-
Diez S, Besendörfer M, Weyerer V, Hartmann A, Moosmann J, Weiss C, Renner M, and Müller H
- Abstract
Background: Deleted in malignant brain tumors 1 (DMBT1) is involved in innate immunity and epithelial differentiation. It has been proven to play a role in various states of inflammation or hypoxia of fetal gastrointestinal and pulmonary diseases. Discrimination of pathogenesis in necrotizing enterocolitis (NEC) based on cardiac status improves the understanding of NEC in different patient subgroups. We aimed at examining DMBT1 expressions regarding their association with cardiac status leading to impaired intestinal perfusion, intraoperative bacteria proof, and a fulminant course of NEC., Methods: Twenty-eight patients with NEC were treated surgically between 2010 and 2019 at our institution. DMBT1 expression was examined in intestinal sections using immunohistochemistry to detect DMBT1 protein. Associations of clinical parameters and DMBT1 expression were analyzed., Results: We examined DMBT1 levels in 10 patients without cardiac defects and 18 patients with persisting ductus arteriosus (PDA) and congenital heart defects (CHD). Compared to patients without cardiac malformations, DMBT1 levels tended to score higher in patients with PDA/CHD (p = 0.2113) and were negatively correlated with C-reactive protein in these infants (p = 0.0172; r = - 0.5533). The number of DMBT1-expressing macrophages was elevated in the PDA/CHD-subgroup (p = 0.0399). Ratios of neutrophils and monocytes to lymphocytes were significantly higher in infants with PDA/CHD (p = 0.0319 and 0.0493). DMBT1 expression was significantly associated with positive bacterial culture of intraoperative swabs (p = 0.0252) and DMBT1 expression of the serosa was associated with a fulminant course of NEC (p = 0.0239)., Conclusions: This study demonstrates that DMBT1 expression may be influenced by cardiac anomalies with an impaired intestinal perfusion in the neonatal intestine. NEC in PDA/CHD infants is associated with more DMBT1-positive macrophages and a significantly elevated neutrophil-to-lymphocyte ratio., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
22. Scaling the U-net: segmentation of biodegradable bone implants in high-resolution synchrotron radiation microtomograms.
- Author
-
Baltruschat IM, Ćwieka H, Krüger D, Zeller-Plumhoff B, Schlünzen F, Willumeit-Römer R, Moosmann J, and Heuser P
- Subjects
- Artifacts, Deep Learning, False Positive Reactions, Humans, Image Processing, Computer-Assisted, Materials Science, Neural Networks, Computer, Osseointegration, Prostheses and Implants, Reproducibility of Results, Biodegradation, Environmental, Synchrotrons, X-Ray Microtomography methods
- Abstract
Highly accurate segmentation of large 3D volumes is a demanding task. Challenging applications like the segmentation of synchrotron radiation microtomograms (SRμCT) at high-resolution, which suffer from low contrast, high spatial variability and measurement artifacts, readily exceed the capacities of conventional segmentation methods, including the manual segmentation by human experts. The quantitative characterization of the osseointegration and spatio-temporal biodegradation process of bone implants requires reliable, and very precise segmentation. We investigated the scaling of 2D U-net for high resolution grayscale volumes by three crucial model hyper-parameters (i.e., the model width, depth, and input size). To leverage the 3D information of high-resolution SRμCT, common three axes prediction fusing is extended, investigating the effect of adding more than three axes prediction. In a systematic evaluation we compare the performance of scaling the U-net by intersection over union (IoU) and quantitative measurements of osseointegration and degradation parameters. Overall, we observe that a compound scaling of the U-net and multi-axes prediction fusing with soft voting yields the highest IoU for the class "degradation layer". Finally, the quantitative analysis showed that the parameters calculated with model segmentation deviated less from the high quality results than those obtained by a semi-automatic segmentation method., (© 2021. The Author(s).)
- Published
- 2021
- Full Text
- View/download PDF
23. High-resolution and sensitivity bi-directional x-ray phase contrast imaging using 2D Talbot array illuminators.
- Author
-
Gustschin A, Riedel M, Taphorn K, Petrich C, Gottwald W, Noichl W, Busse M, Francis SE, Beckmann F, Hammel JU, Moosmann J, Thibault P, and Herzen J
- Abstract
Two-dimensional (2D) Talbot array illuminators (TAIs) were designed, fabricated, and evaluated for high-resolution high-contrast x-ray phase imaging of soft tissue at 10-20 keV. The TAIs create intensity modulations with a high compression ratio on the micrometer scale at short propagation distances. Their performance was compared with various other wavefront markers in terms of period, visibility, flux efficiency, and flexibility to be adapted for limited beam coherence and detector resolution. Differential x-ray phase contrast and dark-field imaging were demonstrated with a one-dimensional, linear phase stepping approach yielding 2D phase sensitivity using unified modulated pattern analysis (UMPA) for phase retrieval. The method was employed for x-ray phase computed tomography reaching a resolution of 3 µm on an unstained murine artery. It opens new possibilities for three-dimensional, non-destructive, and quantitative imaging of soft matter such as virtual histology. The phase modulators can also be used for various other x-ray applications such as dynamic phase imaging, super-resolution structured illumination microscopy, or wavefront sensing., Competing Interests: The authors declare no conflicts of interest., (Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.)
- Published
- 2021
- Full Text
- View/download PDF
24. Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratio in Univentricular Patients From Birth to Follow-Up After Fontan-Predicting Lymphatic Abnormalities.
- Author
-
Moosmann J, Schroeder C, Cesnjevar R, Rottermann K, Weigelt A, and Dittrich S
- Abstract
Background: Reliable laboratory parameters identifying complications after Fontan surgery including the lymphatic abnormalities and the development of protein-losing enteropathy (PLE) are rare. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocte ratio (PLR) are inflammatory markers and have been studied to predict outcome and prognosis in various diseases. The aim of this study was to investigate NLR and PLR from birth to follow-up after Fontan and evaluate their use as prognostic parameters for single ventricle patients regarding the development of lymphatic malformations during follow-up. Materials and Methods: Sixty-six univentricular patients who underwent Fontan surgery and had 6-month follow-up magnetic resonance imaging (MRI) with T2 weighted lymphatic imaging after total cavopulmonary connection (TCPC) surgery were included in the study. NLR and PLR were determined at specific time points, from neonatal age to follow-up after Fontan operation and correlated to data from the MRI 6 months after Fontan. Results: NLR and PLR increase significantly over time from the first surgery during infancy to the follow-up after Fontan (both p < 0.0001), with a significant increase after the Glenn surgery for both ratios (each p < 0.0001). Higher NLR ( p = 0.002) and higher PLR ( p = 0.004) correlated with higher-grade classification of lymphatic abnormalities in T2-weighted imaging 6 months after Fontan surgery and higher NLR correlated with higher transpulmonary gradient prior to Fontan surgery ( p = 0.035) Both ratios showed a significant correlation to total protein at follow-up (NLR p = 0.0038; PLR<0.0001). Conclusion: Increased NLR and PLR correlate with higher degree lymphatic malformations after TCPC and therefore might contribute as valuable additional biomarker during follow-up after TCPC. NLR and PLR are simple, inexpensive and easily available parameters to complement diagnostics after TCPC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Moosmann, Schroeder, Cesnjevar, Rottermann, Weigelt and Dittrich.)
- Published
- 2021
- Full Text
- View/download PDF
25. Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws.
- Author
-
Peruzzi N, Galli S, Helmholz H, Kardjilov N, Krüger D, Markötter H, Moosmann J, Orlov D, Prgomet Z, Willumeit-Römer R, Wennerberg A, and Bech M
- Subjects
- Absorbable Implants, Alloys, Bone Screws, Corrosion, Materials Testing, X-Ray Microtomography, Gadolinium, Magnesium pharmacology
- Abstract
Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is controversial. Investigating Gd behavior during implant corrosion is thus of utmost importance. In this study, we analyzed the degradation byproducts at the implant site of biodegradable Mg-5Gd and Mg-10Gd implants after 12 weeks healing time, using a combination of different imaging techniques: histology, energy-dispersive x-ray spectroscopy (EDX), x-ray microcomputed tomography (µCT) and neutron µCT. The main finding has been that, at the healing time in exam, the corrosion appears to have involved only the Mg component, which has been substituted by calcium and phosphorus, while the Gd remains localized at the implant site. This was observed in 2D by means of EDX maps and extended to 3D with a novel application of neutron tomography. X-ray fluorescence analysis of the main excretory organs also did not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy happened during degradation. STATEMENT OF SIGNIFICANCE: Gadolinium is among the most promising alloying elements for property control in biodegradable magnesium alloy implants, but its toxicity is controversial and its behavior during corrosion needs to be investigated. We combine 2D energy dispersive x-ray spectroscopy and 3D neutron and x-ray tomography to image the degradation of magnesium-gadolinium implants after 12 weeks of healing time. We find that, at the time in exam, the corrosion has involved only the magnesium component, while the gadolinium remains localized at the implant site. X-ray fluorescence analysis of the main excretory organs also does not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy has happened during degradation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
26. High-resolution ex vivo analysis of the degradation and osseointegration of Mg-xGd implant screws in 3D.
- Author
-
Krüger D, Galli S, Zeller-Plumhoff B, Wieland DCF, Peruzzi N, Wiese B, Heuser P, Moosmann J, Wennerberg A, and Willumeit-Römer R
- Abstract
Biodegradable magnesium (Mg) alloys can revolutionize osteosynthesis, because they have mechanical properties similar to those of the bone, and degrade over time, avoiding the need of removal surgery. However, they are not yet routinely applied because their degradation behavior is not fully understood. In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium (Gd) at high resolution. Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4, 8 and 12 weeks. Afterward, the degradation rate and degradation homogeneity, as well as bone-to-implant interface, were studied with synchrotron radiation micro computed tomography and histology. Titanium (Ti) and polyether ether ketone (PEEK) were used as controls material to evaluate osseointegration. Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd. Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue. The results were correlated to in vitro data obtained from the same material and shape. The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK. The results suggest that both Mg-xGd alloys are suitable as materials for bone implants., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)
- Published
- 2021
- Full Text
- View/download PDF
27. Evaporation kinetics in highly porous tetrapodal zinc oxide networks studied using in situ SRµCT.
- Author
-
Hindenlang B, Gapeeva A, Baum MJ, Kaps S, Saure LM, Rasch F, Hammel J, Moosmann J, Storm M, Adelung R, Schütt F, and Zeller-Plumhoff B
- Abstract
Tetrapodal zinc oxide (t-ZnO) is used to fabricate polymer composites for many different applications ranging from biomedicine to electronics. In recent times, macroscopic framework structures from t-ZnO have been used as a versatile sacrificial template for the synthesis of multi-scaled foam structures from different nanomaterials such as graphene, hexagonal boron nitride or gallium nitride. Many of these fabrication methods rely on wet-chemical coating processes using nanomaterial dispersions, leading to a strong interest in the actual coating mechanism and factors influencing it. Depending on the type of medium (e.g. solvent) used, different results regarding the homogeneity of the nanomaterial coating can be achieved. In order to understand how a medium influences the coating behavior, the evaporation process of water and ethanol is investigated in this work using in situ synchrotron radiation-based micro computed tomography (SRµCT). By employing propagation-based phase contrast imaging, both the t-ZnO network and the medium can be visualized. Thus, the evaporation process can be monitored non-destructively in three dimensions. This investigation showed that using a polar medium such as water leads to uniform evaporation and, by that, a homogeneous coating of the entire network., (© 2021. The Author(s).)
- Published
- 2021
- Full Text
- View/download PDF
28. Tolvaptan treatment in an adult Fontan patient with protein-losing enteropathy: a serial 23 Na-MRI investigation.
- Author
-
Moosmann J, Toka O, Linz P, Dahlmann A, Nagel AM, Schiffer M, Uder M, Cesnjevar R, Dittrich S, and Kopp C
- Abstract
Background: Protein-losing enteropathy (PLE) is a severe complication of the univentricular Fontan circulation and associated with disturbances in salt and water homeostasis. Fontan patients with PLE have a poor prognosis, with increased morbidity and mortality. Due to limited therapeutic strategies, patients are often treated only symptomatically., Methods: We report our first experience of Tolvaptan (TLV) treatment in a Fontan patient with PLE, severe volume retention and hyponatraemia, refractory to conventional diuretic therapy. In addition to clinical parameters, we monitored drug effects including tissue sodium and volume status via serial
23 Na-magnetic resonance imaging (23 Na-MRI) and bioimpedance spectroscopy compared with age-matched controls., Results:23 Na-MRI identified elevated tissue sodium, which decreased under TLV treatment, as well as volume status, while serum sodium increased and the patient's symptoms improved. During long-term treatment, we were able to differentiate between sodium and volume status in our patient, suggesting that TLV uncoupled body sodium from water., Conclusion: TLV in addition to loop diuretics improved clinical symptoms of PLE and lowered tissue sodium overload. Long-term effects should be further evaluated in Fontan patients., Competing Interests: Conflict of interest statement: The authors declare that there is no conflict of interest., (© The Author(s), 2021.)- Published
- 2021
- Full Text
- View/download PDF
29. Case Report: Trans-axillary Artery Access for Rescue Stent Implantation in an Infant With Retrograde Non-passable Aortic Coarctation.
- Author
-
Moosmann J, Purbojo A, Eder S, and Dittrich S
- Abstract
Primary surgical repair remains the traditional treatment for patients with critical duct-dependent coarctation of the aorta (CoA). Initial surgical repair might not be possible or associated with higher risks if additional comorbidities arise in small infants and neonates. Balloon angioplasty (BA) has been described as a rescue strategy for these children. We describe the feasibility of a palliative BA and rescue stent implantation via an alternative antegrade right-axillary artery approach in an initially inoperable infant with pneumonia and respiratory failure and severe CoA, where the stenosis was not passable by traditional retrograde femoral access. This case adds new aspects to the therapy of critical CoA: Stent implantation provides a bridge to surgery in critically ill infants and does not preclude successful surgical repair. Further, if the classic retrograde approach is not possible, the right axillary artery access should be considered as an alternative to pass the stenosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Moosmann, Purbojo, Eder and Dittrich.)
- Published
- 2021
- Full Text
- View/download PDF
30. Capillarity and active cell movement at mesendoderm translocation in the Xenopus gastrula.
- Author
-
Nagel M, Barua D, Damm EW, Kashef J, Hofmann R, Ershov A, Cecilia A, Moosmann J, Baumbach T, and Winklbauer R
- Subjects
- Animals, Cadherins metabolism, Capillary Action, Cell Adhesion physiology, Endoderm metabolism, Endoderm physiology, Fibronectins metabolism, Gastrula metabolism, Gastrula physiology, Mesoderm metabolism, Pseudopodia metabolism, Pseudopodia physiology, Xenopus laevis metabolism, Cell Movement physiology, Gastrulation physiology, Mesoderm physiology, Xenopus laevis physiology
- Abstract
During Xenopus gastrulation, leading edge mesendoderm (LEM) advances animally as a wedge-shaped cell mass over the vegetally moving blastocoel roof (BCR). We show that close contact across the BCR-LEM interface correlates with attenuated net advance of the LEM, which is pulled forward by tip cells while the remaining LEM frequently separates from the BCR. Nevertheless, lamellipodia persist on the detached LEM surface. They attach to adjacent LEM cells and depend on PDGF-A, cell-surface fibronectin and cadherin. We argue that active cell motility on the LEM surface prevents adverse capillary effects in the liquid LEM tissue as it moves by being pulled. It counters tissue surface-tension effects with oriented cell movement and bulges the LEM surface out to keep it close to the curved BCR without attaching to it. Proximity to the BCR is necessary, in turn, for the maintenance and orientation of lamellipodia that permit mass cell movement with minimal substratum contact. Together with a similar process in epithelial invagination, vertical telescoping, the cell movement at the LEM surface defines a novel type of cell rearrangement: vertical shearing., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)
- Published
- 2021
- Full Text
- View/download PDF
31. Dual Functional States of R406W-Desmin Assembly Complexes Cause Cardiomyopathy With Severe Intercalated Disc Derangement in Humans and in Knock-In Mice.
- Author
-
Herrmann H, Cabet E, Chevalier NR, Moosmann J, Schultheis D, Haas J, Schowalter M, Berwanger C, Weyerer V, Agaimy A, Meder B, Müller OJ, Katus HA, Schlötzer-Schrehardt U, Vicart P, Ferreiro A, Dittrich S, Clemen CS, Lilienbaum A, and Schröder R
- Subjects
- Adolescent, Animals, Cardiac Catheterization methods, Cardiomyopathies diagnostic imaging, Desmin metabolism, Gene Knock-In Techniques methods, Humans, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Myocardium ultrastructure, Pacemaker, Artificial, Cardiomyopathies genetics, Cardiomyopathies therapy, Desmin genetics, Myocardium pathology, Severity of Illness Index
- Abstract
Background: Mutations in the human desmin gene cause myopathies and cardiomyopathies. This study aimed to elucidate molecular mechanisms initiated by the heterozygous R406W-desmin mutation in the development of a severe and early-onset cardiac phenotype., Methods: We report an adolescent patient who underwent cardiac transplantation as a result of restrictive cardiomyopathy caused by a heterozygous R406W-desmin mutation. Sections of the explanted heart were analyzed with antibodies specific to 406W-desmin and to intercalated disc proteins. Effects of the R406W mutation on the molecular properties of desmin were addressed by cell transfection and in vitro assembly experiments. To prove the genuine deleterious effect of the mutation on heart tissue, we further generated and analyzed R405W-desmin knock-in mice harboring the orthologous form of the human R406W-desmin., Results: Microscopic analysis of the explanted heart revealed desmin aggregates and the absence of desmin filaments at intercalated discs. Structural changes within intercalated discs were revealed by the abnormal organization of desmoplakin, plectin, N-cadherin, and connexin-43. Next-generation sequencing confirmed the DES variant c.1216C>T (p.R406W) as the sole disease-causing mutation. Cell transfection studies disclosed a dual behavior of R406W-desmin with both its integration into the endogenous intermediate filament system and segregation into protein aggregates. In vitro, R406W-desmin formed unusually thick filaments that organized into complex filament aggregates and fibrillar sheets. In contrast, assembly of equimolar mixtures of mutant and wild-type desmin generated chimeric filaments of seemingly normal morphology but with occasional prominent irregularities. Heterozygous and homozygous R405W-desmin knock-in mice develop both a myopathy and a cardiomyopathy. In particular, the main histopathologic results from the patient are recapitulated in the hearts from R405W-desmin knock-in mice of both genotypes. Moreover, whereas heterozygous knock-in mice have a normal life span, homozygous animals die at 3 months of age because of a smooth muscle-related gastrointestinal phenotype., Conclusions: We demonstrate that R406W-desmin provokes its severe cardiotoxic potential by a novel pathomechanism, where the concurrent dual functional states of mutant desmin assembly complexes underlie the uncoupling of desmin filaments from intercalated discs and their structural disorganization.
- Published
- 2020
- Full Text
- View/download PDF
32. Multisite measurement of regional oxygen saturation in Fontan patients with and without protein-losing enteropathy at rest and during exercise.
- Author
-
Schröer S, Fahlbusch FB, Münch F, Alkassar M, Toka HR, Rauh M, Rüffer A, Cesnjevar R, Dittrich S, Toka O, and Moosmann J
- Subjects
- Adolescent, Brain metabolism, Child, Child, Preschool, Cohort Studies, Exercise physiology, Humans, Hypoxia etiology, Hypoxia metabolism, Infant, Kidney injuries, Kidney metabolism, Muscle, Skeletal metabolism, Oxygen blood, Postoperative Complications etiology, Postoperative Complications metabolism, Spectroscopy, Near-Infrared, Transposition of Great Vessels surgery, Univentricular Heart surgery, Young Adult, Fontan Procedure adverse effects, Oxygen metabolism, Protein-Losing Enteropathies etiology, Protein-Losing Enteropathies metabolism
- Abstract
Background: Protein-losing enteropathy (PLE) is a severe complication of Fontan circulation with increased risk of end-organ dysfunction. We evaluated tissue oxygenation via near-infrared spectroscopy (NIRS) at different exercise levels in Fontan patients., Methods: Assessment of multisite NIRS during cycle ergometer exercise and daily activities in three groups: Fontan patients with PLE; without PLE; patients with dextro-transposition of the great arteries (d-TGA); comparing univentricular with biventricular circulation and Fontan with/without PLE. Renal threshold analysis (<65%;<55%;<45%) of regional oxygen saturation (rSO2) was performed., Results: Fontan patients showed reduced rSO2 (p < 0.05) in their quadriceps femoris muscle compared with biventricular d-TGA patients at all time points. rSO2 in renal tissue was reduced at baseline (p = 0.002), exercise (p = 0.0062), and daily activities (p = 0.03) in Fontan patients with PLE. Renal threshold analysis identified critically low renal rSO2 (rSO2 < 65%) in Fontan patients with PLE during exercise (95% of monitoring time below threshold) and daily activities (83.7% time below threshold)., Conclusion: Fontan circulation is associated with decreased rSO2 values in skeletal muscle and hypoxemia of renal tissue solely in patients with PLE. Reduced rSO2 already during activities of daily life, might contribute to comorbidities in patients with Fontan circulation, including PLE and renal failure.
- Published
- 2019
- Full Text
- View/download PDF
33. First experience with Tolvaptan for the treatment of neonates and infants with capillary leak syndrome after cardiac surgery.
- Author
-
Kerling A, Toka O, Rüffer A, Müller H, Habash S, Weiss C, Dittrich S, and Moosmann J
- Subjects
- Airway Management, Blood Transfusion, Body Weight drug effects, Capillary Leak Syndrome etiology, Capillary Leak Syndrome therapy, Diuretics therapeutic use, Female, Fluid Therapy, Humans, Infant, Infant, Newborn, Liver metabolism, Male, Osmoregulation drug effects, Postoperative Complications drug therapy, Retrospective Studies, Sodium blood, Urination drug effects, Antidiuretic Hormone Receptor Antagonists therapeutic use, Capillary Leak Syndrome drug therapy, Cardiac Surgical Procedures adverse effects, Tolvaptan therapeutic use
- Abstract
Background: Postoperative fluid management in critically ill neonates and infants with capillary leak syndrome (CLS) and extensive volume overload after cardiac surgery on cardiopulmonary bypass is challenging. CLS is often resistant to conventional diuretic therapy, aggravating the course of weaning from invasive ventilation, increasing length of stay on ICU and morbidity and mortality., Methods: Tolvaptan (TLV, vasopressin type 2 receptor antagonist) was used as an additive diuretic in neonates and infants with CLS after cardiac surgery. Retrospective analysis of 25 patients with CLS including preoperative and postoperative parameters was performed. Multivariate regression analysis was performed to identify predictors for TLV response., Results: Multivariate analysis identified urinary output during 24 h after TLV administration and mean blood pressure (BP) on day 2 of TLV treatment as predictors for TLV response (AUC = 0.956). Responder showed greater weight reduction (p < 0.0001), earlier weaning from ventilator during TLV (p = 0.0421) and shorter time in the ICU after TLV treatment (p = 0.0155). Serum sodium and serum osmolality increased significantly over time in all patients treated with TLV., Conclusion: In neonates and infants with diuretic-refractory CLS after cardiac surgery, additional aquaretic therapy with TLV showed an increase in urinary output and reduction in bodyweight in patients classified as TLV responder. Increase in urinary output and mean BP on day 2 of treatment were strong predictors for TLV response.
- Published
- 2019
- Full Text
- View/download PDF
34. Influence of factor XIII activity on post-operative transfusion in congenital cardiac surgery-A retrospective analysis.
- Author
-
Fahlbusch FB, Heinlein T, Rauh M, Dittrich S, Cesnjevar R, Moosmann J, Nadal J, Schmid M, Muench F, Schroth M, Rascher W, and Topf HG
- Subjects
- Adolescent, Blood Coagulation, Blood Transfusion statistics & numerical data, Chest Tubes statistics & numerical data, Child, Child, Preschool, Cyanosis diagnosis, Cyanosis physiopathology, Drainage statistics & numerical data, Female, Heart Defects, Congenital surgery, Humans, Infant, Infant, Newborn, Intensive Care Units, Pediatric, Male, Postoperative Hemorrhage blood, Postoperative Hemorrhage prevention & control, Retrospective Studies, Risk Factors, Cardiopulmonary Bypass methods, Factor XIII metabolism, Heart Defects, Congenital blood, Postoperative Hemorrhage diagnosis
- Abstract
Objectives: Coagulation factor XIII (FXIII) plays a key role in fibrin clot stabilization-an essential process for wound healing following cardiothoracic surgery. However, FXIII deficiency as a risk for post-operative bleeding in pediatric cardiac surgery involving cardiopulmonary bypass (CPB) for congenital heart disease (CHD) is controversially discussed. Thus, as primary outcome measures, we analyzed the association of pre-operative FXIII activity and post-operative chest tube drainage (CTD) loss with transfusion requirements post-operatively. Secondary outcomes included the influence of cyanosis and sex on transfusion., Methods: Our retrospective analysis (2009-2010) encompassed a single center series of 76 cardio-surgical cases with CPB (0-17 years, mean age 5.61 years) that were post-operatively admitted to our pediatric intensive care unit (PICU). The observational period was 48 hours after cardiac surgery. Blood cell counts and coagulation status, including FXIII activity were routinely performed pre- and post-operatively. The administered amount of blood products and volume expanders was recorded electronically, along with the amount of CTD loss. Uni- and multivariate logistic regression analysis was performed to calculate the associations (odds ratios) of variables with post-operative transfusion needs., Results: FXIII activities remained stable following CPB surgery. There was no association of pre- and post-operative FXIII activities and transfusion of blood products or volume expanders in the first 48 hours after surgery. Similarly, FXIII showed no association with CTD loss. Cyanosis and female sex were associated with transfusion rates., Conclusions: Although essentially involved in wound healing and clotting after surgery, FXIII activity does not serve as a valid predictor of post-operative transfusion need., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2018
- Full Text
- View/download PDF
35. Gauging low-dose X-ray phase-contrast imaging at a single and large propagation distance.
- Author
-
Hofmann R, Schober A, Hahn S, Moosmann J, Kashef J, Hertel M, Weinhardt V, Hänschke D, Helfen L, Sánchez Salazar IA, Guigay JP, Xiao X, and Baumbach T
- Abstract
The interactions of a beam of hard and spatio-temporally coherent X-rays with a soft-matter sample primarily induce a transverse distribution of exit phase variations δϕ (retardations or advancements in pieces of the wave front exiting the object compared to the incoming wave front) whose free-space propagation over a distance z gives rise to intensity contrast gz. For single-distance image detection and |δϕ| ≪ 1 all-order-in-z phase-intensity contrast transfer is linear in δϕ. Here we show that ideal coherence implies a decay of the (shot-)noise-to-signal ratio in gz and of the associated phase noise as z(-1/2) and z(-1), respectively. Limits on X-ray dose thus favor large values of z. We discuss how a phase-scaling symmetry, exact in the limit δϕ → 0 and dynamically unbroken up to |δϕ| ∼ 1, suggests a filtering of gz in Fourier space, preserving non-iterative quasi-linear phase retrieval for phase variations up to order unity if induced by multi-scale objects inducing phase variations δϕ of a broad spatial frequency spectrum. Such an approach continues to be applicable under an assumed phase-attenuation duality. Using synchrotron radiation, ex and in vivo microtomography on frog embryos exemplifies improved resolution compared to a conventional single-distance phase-retrieval algorithm.
- Published
- 2016
- Full Text
- View/download PDF
36. Novel loci for non-syndromic coarctation of the aorta in sporadic and familial cases.
- Author
-
Moosmann J, Uebe S, Dittrich S, Rüffer A, Ekici AB, and Toka O
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Chromosomes, Human, X genetics, Female, Humans, Infant, Male, Middle Aged, Pedigree, Septins genetics, TRPM Cation Channels genetics, Aortic Coarctation genetics, DNA Copy Number Variations, Genetic Loci
- Abstract
Background: Coarctation of the aorta (CoA) accounts for 5-8% of all congenital heart defects. CoA can be detected in up to 20% of patients with Ullrich-Turner syndrome (UTS), in which a part or all of one of the X chromosomes is absent. The etiology of non-syndromic CoA is poorly understood. In the present work, we test the hypothesis that rare copy number variation (CNV) especially on the gonosomes, contribute to the etiology of non-syndromic CoA., Methods: We performed high-resolution genome-wide CNV analysis using the Affymetrix SNP 6.0 microarray platform for 70 individuals with sporadic CoA, 3 families with inherited CoA (n=13) and 605 controls. Our analysis comprised genome wide association, CNV burden and linkage. CNV was validated by multiplex ligation-dependent probe amplification., Results: We identified a significant abundance of large (>100 kb) CNVs on the X chromosome in males with CoA (p=0.005). 11 out of 51 (~ 22%) male cases had these large CNVs. Association analysis in the sporadic cohort revealed 14 novel loci for CoA. The locus on 21q22.3 in the sporadic CoA cohort overlapped with a gene locus identified in all familial cases of CoA (candidate gene TRPM2). We identified one CNV locus within a locus with high multipoint LOD score from a linkage analysis of the familial cases (SEPT9); another locus overlapped with a region implicated in Kabuki syndrome. In the familial cases, we identified a total of 7 CNV loci that were exclusively present in cases but not in unaffected family members., Conclusion: Of all candidate loci identified, the TRPM2 locus was the most frequently implicated autosomal locus in sporadic and familial cases. However, the abundance of large CNVs on the X chromosome of affected males suggests that gonosomal aberrations are not only responsible for syndromic CoA but also involved in the development of sporadic and non-syndromic CoA and their male dominance.
- Published
- 2015
- Full Text
- View/download PDF
37. TV-based conjugate gradient method and discrete L-curve for few-view CT reconstruction of X-ray in vivo data.
- Author
-
Yang X, Hofmann R, Dapp R, van de Kamp T, dos Santos Rolo T, Xiao X, Moosmann J, Kashef J, and Stotzka R
- Abstract
High-resolution, three-dimensional (3D) imaging of soft tissues requires the solution of two inverse problems: phase retrieval and the reconstruction of the 3D image from a tomographic stack of two-dimensional (2D) projections. The number of projections per stack should be small to accommodate fast tomography of rapid processes and to constrain X-ray radiation dose to optimal levels to either increase the duration of in vivo time-lapse series at a given goal for spatial resolution and/or the conservation of structure under X-ray irradiation. In pursuing the 3D reconstruction problem in the sense of compressive sampling theory, we propose to reduce the number of projections by applying an advanced algebraic technique subject to the minimisation of the total variation (TV) in the reconstructed slice. This problem is formulated in a Lagrangian multiplier fashion with the parameter value determined by appealing to a discrete L-curve in conjunction with a conjugate gradient method. The usefulness of this reconstruction modality is demonstrated for simulated and in vivo data, the latter acquired in parallel-beam imaging experiments using synchrotron radiation.
- Published
- 2015
- Full Text
- View/download PDF
38. A common genetic variant within SCN10A modulates cardiac SCN5A expression.
- Author
-
van den Boogaard M, Smemo S, Burnicka-Turek O, Arnolds DE, van de Werken HJ, Klous P, McKean D, Muehlschlegel JD, Moosmann J, Toka O, Yang XH, Koopmann TT, Adriaens ME, Bezzina CR, de Laat W, Seidman C, Seidman JG, Christoffels VM, Nobrega MA, Barnett P, and Moskowitz IP
- Subjects
- Adult, Animals, Arrhythmias, Cardiac etiology, Arrhythmias, Cardiac genetics, Arrhythmias, Cardiac physiopathology, Enhancer Elements, Genetic, Female, Gene Expression Regulation, Heart embryology, Humans, Male, Mice, Mice, Transgenic, NAV1.5 Voltage-Gated Sodium Channel physiology, NAV1.8 Voltage-Gated Sodium Channel physiology, Polymorphism, Single Nucleotide, Pregnancy, Promoter Regions, Genetic, RNA, Messenger genetics, RNA, Messenger metabolism, Genetic Variation, Myocardium metabolism, NAV1.5 Voltage-Gated Sodium Channel genetics, NAV1.8 Voltage-Gated Sodium Channel genetics
- Abstract
Variants in SCN10A, which encodes a voltage-gated sodium channel, are associated with alterations of cardiac conduction parameters and the cardiac rhythm disorder Brugada syndrome; however, it is unclear how SCN10A variants promote dysfunctional cardiac conduction. Here we showed by high-resolution 4C-seq analysis of the Scn10a-Scn5a locus in murine heart tissue that a cardiac enhancer located in Scn10a, encompassing SCN10A functional variant rs6801957, interacts with the promoter of Scn5a, a sodium channel-encoding gene that is critical for cardiac conduction. We observed that SCN5A transcript levels were several orders of magnitude higher than SCN10A transcript levels in both adult human and mouse heart tissue. Analysis of BAC transgenic mouse strains harboring an engineered deletion of the enhancer within Scn10a revealed that the enhancer was essential for Scn5a expression in cardiac tissue. Furthermore, the common SCN10A variant rs6801957 modulated Scn5a expression in the heart. In humans, the SCN10A variant rs6801957, which correlated with slowed conduction, was associated with reduced SCN5A expression. These observations establish a genomic mechanism for how a common genetic variation at SCN10A influences cardiac physiology and predisposes to arrhythmia.
- Published
- 2014
- Full Text
- View/download PDF
39. X-ray phase-contrast in vivo microtomography probes new aspects of Xenopus gastrulation.
- Author
-
Moosmann J, Ershov A, Altapova V, Baumbach T, Prasad MS, LaBonne C, Xiao X, Kashef J, and Hofmann R
- Subjects
- Animals, Biological Evolution, Cell Movement, Endoderm embryology, Head embryology, Imaging, Three-Dimensional instrumentation, Imaging, Three-Dimensional methods, Mesoderm embryology, Morphogenesis, Movement, Rotation, Time Factors, X-Ray Microtomography instrumentation, Xenopus laevis anatomy & histology, Gastrulation physiology, X-Ray Microtomography methods, Xenopus laevis embryology
- Abstract
An ambitious goal in biology is to understand the behaviour of cells during development by imaging-in vivo and with subcellular resolution-changes of the embryonic structure. Important morphogenetic movements occur throughout embryogenesis, but in particular during gastrulation when a series of dramatic, coordinated cell movements drives the reorganization of a simple ball or sheet of cells into a complex multi-layered organism. In Xenopus laevis, the South African clawed frog and also in zebrafish, cell and tissue movements have been studied in explants, in fixed embryos, in vivo using fluorescence microscopy or microscopic magnetic resonance imaging. None of these methods allows cell behaviours to be observed with micrometre-scale resolution throughout the optically opaque, living embryo over developmental time. Here we use non-invasive in vivo, time-lapse X-ray microtomography, based on single-distance phase contrast and combined with motion analysis, to examine the course of embryonic development. We demonstrate that this powerful four-dimensional imaging technique provides high-resolution views of gastrulation processes in wild-type X. laevis embryos, including vegetal endoderm rotation, archenteron formation, changes in the volumes of cavities within the porous interstitial tissue between archenteron and blastocoel, migration/confrontation of mesendoderm and closure of the blastopore. Differential flow analysis separates collective from relative cell motion to assign propulsion mechanisms. Moreover, digitally determined volume balances confirm that early archenteron inflation occurs through the uptake of external water. A transient ectodermal ridge, formed in association with the confrontation of ventral and head mesendoderm on the blastocoel roof, is identified. When combined with perturbation experiments to investigate molecular and biomechanical underpinnings of morphogenesis, our technique should help to advance our understanding of the fundamentals of development.
- Published
- 2013
- Full Text
- View/download PDF
40. Phase contrast laminography based on Talbot interferometry.
- Author
-
Altapova V, Helfen L, Myagotin A, Hänschke D, Moosmann J, Gunneweg J, and Baumbach T
- Subjects
- Computer Simulation, Computer-Aided Design, Equipment Design, Equipment Failure Analysis, Interferometry instrumentation, Models, Theoretical, Refractometry instrumentation, Synchrotrons instrumentation
- Abstract
Synchrotron laminography is combined with Talbot grating interferometry to address weakly absorbing specimens. Integrating both methods into one set-up provides a powerful x-ray diagnostical technique for multiple contrast screening of macroscopically large flat specimen and a subsequent non-destructive three-dimensional (3-D) inspection of regions of interest. The technique simultaneously yields the reconstruction of the 3-D absorption, phase, and the so-called dark-field contrast maps. We report on the theoretical and instrumental implementation of of this novel technique. Its broad application potential is exemplarily demonstrated for the field of cultural heritage, namely study of the historical Dead Sea parchment.
- Published
- 2012
- Full Text
- View/download PDF
41. Criticality in single-distance phase retrieval.
- Author
-
Hofmann R, Moosmann J, and Baumbach T
- Subjects
- Computer Simulation, Fourier Analysis, Light, Scattering, Radiation, Models, Theoretical, Radiographic Image Interpretation, Computer-Assisted methods, Refractometry methods
- Abstract
We investigate why in free-space propagation single-distance phase retrieval based on a modified contrast-transfer function of linearized Fresnel theory yields good results for moderately strong pure-phase objects. Upscaling phase-variations in the exit plane, the growth of maxima of the modulus of the Fourier transformed intensity contrast dominates the minima. Cutting out small regions around the latter thus keeps information loss due to nonlocal, nonlinear effects negligible. This quasiparticle approach breaks down at a critical upscaling where the positions of the minima start to move rapidly. We apply our results to X-ray data of an early-stage Xenopus (frog) embryo.
- Published
- 2011
- Full Text
- View/download PDF
42. Single-distance phase retrieval at large phase shifts.
- Author
-
Moosmann J, Hofmann R, and Baumbach T
- Subjects
- Animals, Fourier Analysis, Linear Models, Synchrotrons, Xenopus, Algorithms, Nonlinear Dynamics, Radiographic Image Interpretation, Computer-Assisted methods, Tomography, X-Ray methods
- Abstract
For coherent X-ray imaging of pure phase objects we study the reliability of linear relations in phase-retrieval algorithms based on a single intensity map after free-space propagation. For large phase changes and/or large propagation distances we propose two venues of working beyond linearity: Projection onto an effective, linear and local model in Fourier space and expansion of intensity contrast in powers of object-detector distance. We apply both algorithms successfully to simulated data.
- Published
- 2011
- Full Text
- View/download PDF
43. Nonlinear phase retrieval from single-distance radiograph.
- Author
-
Moosmann J, Hofmann R, Bronnikov A, and Baumbach T
- Subjects
- Nonlinear Dynamics, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Imaging, Three-Dimensional methods, Microscopy, Phase-Contrast methods, Radiographic Image Interpretation, Computer-Assisted methods
- Abstract
Phase contrast in the object plane of a phase object is retrieved from intensity contrast at a {\sl single} object-detector distance. Expanding intensity contrast and phase shift in the detector plane in powers of object-detector distance, phase retrieval is performed beyond the solution to the linearized transport-of-intensity equation. The expansion coefficients are determined by the entire paraxial wave equation. The Laplacian of the phase shift in the object plane thus is written as a local expression linear in the intensity contrast and nonlinear in the phase shift in the object plane. A perturbative approach to this expression is proposed and tested with simulated phantom data.
- Published
- 2010
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.